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Sensitivity of leaf size and shape to climate: Global patterns and paleoclimatic applications
Abstract
• Paleobotanists have long used models based on leaf size and shape to reconstruct paleoclimate. However, most models incorporate a single variable or use traits that are not physiologically or functionally linked to climate, limiting their predictive power. Further, they often underestimate paleotemperature relative to other proxies. • Here we quantify leaf-climate correlations from 92 globally distributed, climatically diverse sites, and explore potential confounding factors. Multiple linear regression models for mean annual temperature (MAT) and mean annual precipitation (MAP) are developed and applied to nine well-studied fossil floras. • We find that leaves in cold climates typically have larger, more numerous teeth, and are more highly dissected. Leaf habit (deciduous vs evergreen), local water availability, and phylogenetic history all affect these relationships. Leaves in wet climates are larger and have fewer, smaller teeth. Our multivariate MAT and MAP models offer moderate improvements in precision over univariate approaches (± 4.0 vs 4.8°C for MAT) and strong improvements in accuracy. For example, our provisional MAT estimates for most North American fossil floras are considerably warmer and in better agreement with independent paleoclimate evidence. • Our study demonstrates that the inclusion of additional leaf traits that are functionally linked to climate improves paleoclimate reconstructions. This work also illustrates the need for better understanding of the impact of phylogeny and leaf habit on leaf-climate relationships.
... Many studies have shown that we can quantify the response of leaves of extant plant species to climatic conditions and use this knowledge to infer how closely related species responded to climate change in the past, based on the anatomy of fossil leaves. Leaf measures that have been analysed in the past include leaf area and shape as a response to the mean annual temperature [1]; carbon isotope fractionation as a response to the mean annual precipitation [2]; stomatal size and density as responses to light availability and the temperature [3]; leaf size as an indicator of the growth temperature (although this has been criticised for over-use [4]); many novel physiognomic characters such as the tooth area and number of teeth on leaf margins as responses to the mean annual temperature [5]; and a combination of leaf characters to reconstruct how open the vegetation was [4]. ...
... Nothofagus cunninghamii leaves decreased in leaf area with an increase in summer rainfall, and this relationship is strong ( Table 2). The leaf area was found to increase with increasing mean annual precipitation in a meta-analysis of over 1900 species [1]. We chose to focus on summer precipitation as this variable is likely to be a greater limiting factor to leaf maturation than the mean annual precipitation for N. cunninghamii, which grows in a region where summer is the driest season [34]. ...
... We chose to focus on summer precipitation as this variable is likely to be a greater limiting factor to leaf maturation than the mean annual precipitation for N. cunninghamii, which grows in a region where summer is the driest season [34]. Thus, N. cunninghamii leaves may still follow the trend concluded by Peppe et al. [1] related to the mean annual rainfall. Future research could explicitly test this, but this hypothesis is not within the scope of this paper. ...
Fossil leaf anatomy has previously been used as a proxy for paleoclimate. However, the exposure of leaves to sun or shade during their growth can lead to morphotype differences that confound the interpretation of fossil leaf anatomy in relation to climate and prevent reliable paleoclimate reconstruction. This work aims to model the differences in leaf anatomy that are due to various climatic drivers and differences attributable to sun or shade positions, using Nothofagus cunninghamii as the model species. Leaves from the sun and shade parts of three trees have been sampled from each of 11 sites in Victoria and Tasmania, Australia. The gross morphological and cuticular features have been scored and modelled with climate data from the sites. Random forest models can accurately predict Nothofagus cunninghamii contemporary climatic conditions of the spring temperature and summer rainfall based on leaf anatomical measurements. Leaf area, stomatal density and epidermal cell density are the most accurate predictors of whether a leaf grew in the sun or shade. Leaf area is also the strongest predictor of the maximum and minimum spring temperatures and rainfall. The models have implications for the use of fossilised leaves in paleoclimate reconstruction. The models we have built can be used to effectively predict whether a fossil leaf was from a sun or shade position on the tree and thus enable more reliable inference of paleoclimate by removing the confounding issues of variable leaf anatomy due to sun exposure during growth. Finally, these models could conceivably be used to make predictions of past paleoclimatic conditions provided suitable training and validation data on climatic conditions are available.
... Because physiological traits are difficult to measure and are variable, they often exhibit significant covariance with morphological and chemical traits used for large-scale or multispecies ecological research [4,5]. Among leaf morphologic traits, leaf size and shape are the first considerations due to their importance for energy balance and hydraulic structure [15][16][17]. Normally, large or broad-round leaves are considered advantageous in cool, humid or shady habitats because their thick leaf margins induce large resistance to the transport of heat and substances [15,[18][19][20], whereas small or narrow leaves predominate in hot, dry and high-light environments due to their capacity to decrease leaf temperature, avoid leaf damage and maintain leaf water balance [16,21]. However, large or broad leaves are dominant under the conditions of high temperature or light because they can promote leaf carbon acquisition [20,22]. ...
... Among leaf morphologic traits, leaf size and shape are the first considerations due to their importance for energy balance and hydraulic structure [15][16][17]. Normally, large or broad-round leaves are considered advantageous in cool, humid or shady habitats because their thick leaf margins induce large resistance to the transport of heat and substances [15,[18][19][20], whereas small or narrow leaves predominate in hot, dry and high-light environments due to their capacity to decrease leaf temperature, avoid leaf damage and maintain leaf water balance [16,21]. However, large or broad leaves are dominant under the conditions of high temperature or light because they can promote leaf carbon acquisition [20,22]. ...
... Our finding that leaf area was the best leaf trait predicting (significantly positively related to) species dominance, height and cover in most sites and almost all climate zones and vegetation types (Figures 2, 3, S1 and S2) supports the widespread importance of the light acquisition capacity of species in their community performance [50,51]. The finding also implies that, in most woody communities, interspecific light competition is ubiquitous, and large leaves can help species form a dense canopy to intercept light effectively and accumulate carbon quickly [16,28,33,52]. These species, thus, tend to grow tall and occupy a wide space, which, in turn, enhances their light competition. ...
Leaf traits can reflect plant photosynthetic capacity, resource utilization strategy and adaptability to the environment. However, whether species’ leaf traits are tightly related to the functioning of their community and how that relationship varies with environmental gradients remain largely unexplored. We measured 6 leaf traits, including petiole fineness (PF), specific leaf area (SLA), leaf area (LA), leaf length–width ratio (LLWR), leaf nitrogen content (LN) and leaf phosphorus content (LP), of 733 populations (415 species) of 19 woody angiosperm communities in the eastern Qinghai–Tibetan Plateau across multiple climatic zones or vegetation types. Through meta-analysis and relative importance analysis, the relationship between leaf traits of species and their community dominance and its change with environments were analyzed. The results showed that species dominance was correlated positively with their LA and LP, suggesting that species with high light interception and resource utilization capacity can easily become dominant species in woody angiosperm communities. Along the altitudinal gradient, the effect of PF and SLA on species dominance increased and changed significantly in their pattern, from positive or nonsignificant in temperate forests to negative in alpine and subalpine shrubs, suggesting that increasing petiole mechanical support and lamina protection cost is a dominant leaf growth strategy in stressful high-altitude environments. Our findings demonstrate that the demand for efficient light acquisition and/or utilization and species adaptability or tolerance to specific environmental stress are key mechanisms by which leaf traits govern community composition and functioning.
... For this reason, their inclusion in a phylogenetic framework produces controversial results. Fossil leaves may help in deciphering the evolution and relationships within the Nothofagus (Hill 1994) as the variations in leaf shape and size of these plants could have been directly influenced by the surrounding climate and environmental conditions (Peppe et al. 2011;Vento et al. 2021;Wilf et al. 1998). The differences in leaf morphology are important characters in delimiting the species of Nothofagus and they also bring information about the past environmental and climate conditions as well as about the evolution and adaptation of species (Premoli 1996). ...
... The physiognomy of an individual leaf reflects the microclimate conditions and may reveal the adaptive strategies adopted by plants in different habitats or environments (Davis and Taylor 1980;McPherson et al. 2004). Leaf shape and size of both living and extinct angiosperms have been strongly related to temperature and rainfall conditions respectively (Peppe et al. 2011;Vento et al. 2022b;Wilf et al. 1998;Wright et al. 2017). Extinct and living species of Nothofagaceae are mainly characterized by the presence of compound teeth, a feature that distinguishes the Fagaceae from the Betulaceae (Fig. 1). ...
... Even though both these extinct taxa were recorded in Tasmania, changes in margin shape could reflect a transition toward a leaf adaptation (since Miocene) to warmer and humid climate conditions in New Caledonia and Papua New Guinea (Hill 1992). On the other hand, deciduous taxa are more likely to be toothed than evergreen taxa, and the leaf life-span (deciduous or evergreen) influences on size and number of teeth (Peppe et al. 2011;Royer et al. 2005). ...
The Nothofagus (southern beech) has a rich fossil record and a number of living species distributed exclusively in the Southern Hemisphere. Many attempts have been made to clarify the phylogenetic relationships in Nothofagus but only a few works have included fossil specimens in a phylogenetic framework for a more accurate resolution. Fossil leaves play an important role in deciphering of the evolutionary processes and are a necessary complement in phylogenetic studies. Fossils of Nothofagus have been found in sediments of Antarctica, Australia, New Zealand, New Caledonia, Papua New Guinea, and South America. Here, we performed a phylogenetic analysis including fossils from these areas and examined the character evolution, especially those referred to the morphology of the leaf. Fossil leaves from Antarctica were revised and included in the analysis for the first time. Our results support the monophyly of the four currently recognized subgenera, and novel relationships between extinct and living taxa are discussed. Morphological features of fossil leaves were expressed differently, especially in the teeth shape, size, and secondary venation pattern, when compared to the extant taxa probably related to past climate conditions. The most ancient leaves were recorded in the Upper Cretaceous of Antarctica and placed in subgenera Lophozonia and Fuscospora. Brassospora and Nothofagus are younger clades with distinctive plesiomorphic leaf morphological features. The morphological leaf characters proposed herein, and the inclusion of a considerable number of fossils in our analysis allowed us to provide a study of the evolutionary history of Nothofagus with more precise resolution.
... To carry out paleoclimatic reconstruction using eudicot leaves, fossils that include at least a tip or base and clear evidence of margin characters were assigned to a morphotype using criteria in Ellis et al. (2009), with or without family-, genus-, or species-level identifications. Eudicot morphotypes were recognized from leaf remains, with particular attention to the presence or absence of marginal teeth for leaf margin analysis (LMA; Wing and Greenwood 1993;Wilf 1997;Kowalski and Dilcher 2003;Peppe et al. 2011). A total of 22 leaves or fragments were morphotyped, but only nine leaf types were named. ...
... Twenty-two leaf morphotypes (apps. A1, A2) were used to obtain toothed leaf margin percentages of dicots for LMA (Wing and Greenwood 1993;Wilf 1997;Kowalski and Dilcher 2003;Peppe et al. 2011). Other morphological characteristics, such as leaf shape and size, were also recorded for paleoclimate reconstruction (apps. ...
... A3, A4) using the Climate Leaf Analysis Multivariate Program (CLAMP; Spicer et al. 2021). Leaf size was estimated for all examples of each morphotype using the template in Ellis et al. (2009) for leaf area analysis (LAA; Wilf et al. 1998;Peppe et al. 2011). The score sheet used for CLAMP is available in appendix A4. ...
Premise of research. The Eocene fossil flora of the area around Vancouver, British Columbia is poorly known despite work beginning in the 1890–1920s. The floristic character of the previously unstudied Burnaby Mountain flora from the Huntingdon Formation in British Columbia is reconstructed using plant megafossils and palynology. This site offers insight into the terrestrial vegetation and paleoclimate during the late middle to late Eocene of the Pacific Northwest of North America in a coastal setting during a global cooling trend.
Methodology. Megaflora and microflora were identified, and the combined flora compared to that of coeval floras from northwestern Washington. Paleoclimate was reconstructed from leaf morphology using the Climate Leaf Analysis Multivariate Program, leaf margin analysis, and leaf area analysis. A probabilistic nearest living relative approach was used to reconstruct paleoclimate independently of leaf morphology, using taxonomic identifications from both mega- and microfossils. These data were combined in an ensemble approach.
Pivotal results. The Burnaby Mountain fossil flora is late middle Eocene to late Eocene in age, and shares key plant taxa with the coeval Upper Ravenian flora of the Puget Group and the upper Chumstick Formation of northwestern Washington. The fossil flora contained a mix of subtropical and temperate forest elements, including rare palm and possible cycad leaf fragments, rare conifer pollen, and a diversity of broadleaf trees.
Conclusions. The reconstructed paleoclimate suggests humid warm-temperate to marginally subtropical conditions in coastal British Columbia during the late middle Eocene to late Eocene. An ensemble paleoclimate approach provided a most-parsimonious mean annual temperature estimate of 16.2 ± 3.1 °C for the Burnaby Mountain fossils, and mean annual precipitation of 134 ± 56 cm. A modern climatic analogue is present on the east coast of the United States in North Carolina, where palms are part of the native flora.
... A estrutura da planta mais utilizada como indicador climático é a folha, já que para ter um funcionamento mais eficiente (Spicer et al., 2021) responde rapidamente às condições ambientais a que está exposta (Royer, 2012). Por esta razão, durante quase um século as folhas, principalmente as das angiospermas, têm sido amplamente empregadas pelos paleobotânicos para reconstruir os climas de antigos ecossistemas terrestres, sobretudo os que se desenvolveram entre o Cretáceo e o Quaternário (Royer, 2012;Peppe et al., 2011Peppe et al., , 2018Spicer et al., 2021). Os métodos desenvolvidos para reconstruir os principais parâmetros climáticos, temperatura média anual (TMA) e precipitação média anual (PMA), com base na fisionomia foliar das angiospermas, se sustentam na relação que existe entre o tipo de margem e a TMA, e entre o tamanho da folha e a PMA (Royer, 2012;Peppe et al., 2011Peppe et al., , 2018. ...
... Por esta razão, durante quase um século as folhas, principalmente as das angiospermas, têm sido amplamente empregadas pelos paleobotânicos para reconstruir os climas de antigos ecossistemas terrestres, sobretudo os que se desenvolveram entre o Cretáceo e o Quaternário (Royer, 2012;Peppe et al., 2011Peppe et al., , 2018Spicer et al., 2021). Os métodos desenvolvidos para reconstruir os principais parâmetros climáticos, temperatura média anual (TMA) e precipitação média anual (PMA), com base na fisionomia foliar das angiospermas, se sustentam na relação que existe entre o tipo de margem e a TMA, e entre o tamanho da folha e a PMA (Royer, 2012;Peppe et al., 2011Peppe et al., , 2018. Para reconstruir a TMA e a PMA, os paleobotânicos têm adotado amplamente os métodos conhecidos como Análise da Margem Foliar e Análise da Área Foliar (Peppe et al., 2018). ...
... As reconstruções da TMA baseadas na Análise da Margem Foliar geralmente apresentam um erro de ± 5°C e, caso se utilize uma calibração regional apropriada, o erro é reduzido para aproximadamente ± 2°C (Royer, 2012). Em geral este método subestima a TMA (Peppe et al., 2011), uma vez que as floras fósseis associadas a depósitos fluviais ou lacustres apresentam uma grande proporção de espécies com margem com dentes (Burnham et al., 2001). ...
PALEOCLIMATIC INTERPRETATION BASED ON THE ANALYSIS OF THE LEAF PHYSIOGNOMY OF TWO PLEISTOCENE FLORAS, RIO CLARO FORMATION, SÃO PAULO, BRAZIL. The Jaguariúna and Jazigo Vargem Grande do Sul fossil floras are well-preserved records of an ancestor of one of the phytophysiognomies of the Atlantic Forest, the oldest belt of tropical forest in the world. These fossil floras are associated with the Rio Claro Formation, one of the most important sedimentary records of the Pleistocene from the São Paulo State Peripheral Depression, Brazil. The main physiognomic characteristics–type of margins and leaf area – of the angiosperm leaves from these floras allowed us to carry out the reconstruction of the mean annual temperature (MAT) and the mean annual precipitation (MAP) for the moment of their deposition. The different equations used to reconstruct the MAT and the MAP are based on univariate methods known as Leaf Margin Analysis and Leaf Area Analysis. These equations indicated that the warm and humid subtropical/tropical climate under which the Jaguariúna fossil flora developed was characterized by a MAT of 22.1–22.8°C and a MAP of 566–831 mm, and also that the warm and humid subtropical climate under which the Jazigo Vargem Grande do Sul fossil flora developed was characterized by a MAT of 24.6–25.1°C and a MAP of 747–961 mm. These values indicate that, at the moment of deposition of the fossil floras of Jaguariúna and Jazigo Vargem Grande do Sul, conditions were warmer and less humid than the current ones. Therefore, it is possible to infer that these floras developed in a smaller climatic cycle, the interglacial period, during which the Rio Claro Formation was deposited.
... The Cretaceous-Paleogene extinction event was important in demonstrating that angiosperms, which dominate almost every ecosystem on the planet today, can shift their leaf traits in response to climate change (Blonder et al. 2014). Other environmental factors that are known to interact with leaf traits include SO 2 (Bacon et al. 2013(Bacon et al. , 2021, temperature (Royer et al. 2005(Royer et al. , 2009bPeppe et al. 2011) and light (Evans and Poorter 2001;Aleric and Kirkmann, 2005;Kong et al. 2016). ...
... At the same time, the Irish flora is sufficiently limited to allow a full assessment of its extinction risk and leaf traits to be made, thereby ensuring that taxa from all functional groups within the Irish flora are assessed and that up to date extinction risk assessments are available. Several palaeobotanical (McElwain et al. 1999, 2007Blonder et al. 2014;Soh et al. 2017) and modern flora (Royer et al. 2005(Royer et al. , 2009bPeppe et al. 2011;Bacon et al. 2016) studies have shown that there is a link between leaf traits and the potential to survive environmental upheaval that is driven by climate change. The IUCN Red List (IUCN, 2022) categorises species based on their estimated extinction risk, but does not consider details such as leaf traits (IUCN, 2012a;IUCN, 2012b). ...
... At an individual leaf trait level, strong phylogenetic signals were observed (Table7). A phylogenetic signal at the leaf trait level has previously been shown for leaf traits such as the presence of leaf teeth (Peppe et al. 2011) and leaf vein pattern (Walls 2011). Numerous other studies show a strong relationship between leaf traits and drivers of extinction such as nutrient addition (La Pierre and Smith 2015; Dangremond et al. 2020), pollution (Shafiq et al. 2009;Appalasamy et al. 2017;Dadkhah-Aghdash et al. 2022) and climate (Royer et al. 2005(Royer et al. , 2009bNicotra et al. 2011;Peppe et al. 2011;Bacon et al. 2016); therefore, it appears that the variability observed in leaf traits is correlated with both drivers of extinction and phylogeny, and there is a trade-off between these two processes. ...
Globally, 39% of vascular plant species are estimated to be threatened with extinction. Many factors are responsible for this figure; however, in numerous regions the primary drivers of plant extinction remain unknown. In this study, leaf traits were examined to determine whether there is an association between any specific leaf trait and extinction risk for the Irish flora. Ireland has a relatively small flora that is influenced by a temperate, oceanic climate. Fourteen leaf traits were measured for 1,029 angiosperm taxa, primarily from online herbarium images. Extinction risk was based on national Red List assessments for the Irish flora. Multivariate analysis of the data showed no correlation between leaf traits and extinction risk for the Irish flora. One-way ANOVA and Pearson’s Chi-squared tests largely supported this result, with some indication that leaf teeth may be associated with extinction risk. The correlation of extinction risk and leaf traits with phylogenetic relatedness was also considered, with the presence of a phylogenetic signal detected for the distribution of extinction risk across the Irish flora and significant phylogenetic signal observed for individual leaf traits. It was concluded that the leaf traits analysed do not significantly correlate with the extinction risk of the Irish flora and that leaf traits are not a good predictor of extinction risk for this flora.
... Quantification of PAI from DHP may introduce additional sources of error; for example, its relatively lower resolution compared to TLS could lead to mixed pixels that have a greater chance of misclassification of sky as vegetation . This effect could be enhanced in a Mediterranean forest as trees in drier climates tend to have smaller leaves (Peppe et al., 2011), leading to more small canopy gaps that TLS may resolve where DHP cannot. Further, although we took steps to reduce the error introduced at DHP data acquisition and processing steps, including using automatic thresholding and collecting images with multiple expo-sures, DHP processing requires both model and user assumptions that can impact results. ...
... Wood may be harder to accurately classify than leaves in TLS data (Vicari et al., 2019), resulting in a higher occurrence of false positives in wood clouds, potentially leading to an overestimation in WAI, and therefore underestimation of α, especially in trees with small leaves which are prevalent in dry, Mediterranean environments (Peppe et al., 2011). The problem of misclassification will increase in taller trees due to TLS beam divergence, occlusion and larger beam footprint at further distances (Vicari et al., 2019), suggesting that WAI overestimation could be more pronounced in tall trees. ...
Accurate measurement of vegetation density metrics including plant, wood and leaf area indices (PAI, WAI and LAI) is key to monitoring and modelling carbon storage and uptake in forests. Traditional passive sensor approaches, such as digital hemispherical photography (DHP), cannot separate leaf and wood material, nor individual trees, and require many assumptions in processing. Terrestrial laser scanning (TLS) data offer new opportunities to improve understanding of tree and canopy structure. Multiple methods have been developed to derive PAI and LAI from TLS data, but there is little consensus on the best approach, nor are methods benchmarked as standard. Using TLS data collected in 33 plots containing 2472 trees of 5 species in Mediterranean forests, we compare three TLS methods (lidar pulse, 2D intensity image and voxel-based) to derive PAI and compare with co-located DHP. We then separate leaf and wood in individual tree point clouds to calculate the ratio of wood to total plant area (α), a metric to correct for non-photosynthetic material in LAI estimates. We use individual tree TLS point clouds to estimate how α varies with species, tree height and stand density. We find the lidar pulse method agrees most closely with DHP, but it is limited to single-scan data, so it cannot determine individual tree properties, including α. The voxel-based method shows promise for ecological studies as it can be applied to individual tree point clouds. Using the voxel-based method, we show that species explain some variation in α; however, height and plot density were better predictors. Our findings highlight the value of TLS data to improve fundamental understanding of tree form and function as well as the importance of rigorous testing of TLS data processing methods at a time when new approaches are being rapidly developed. New algorithms need to be compared against traditional methods and existing algorithms, using common reference data. Whilst promising, our results show that metrics derived from TLS data are not yet reliably calibrated and validated to the extent they are ready to replace traditional approaches for large-scale monitoring of PAI and LAI.
... This relationship allowed us to infer past MATs from fossil pEs. In this study, we used the pE obtained from the LMF flora [65% on 55 morphotaxa; Hinojosa et al. (2006) and the equations published by Peppe et al. (2011) and Hinojosa et al. (2011)]. Finally, we used the following categories of the bioclimatic thermal regime nomenclature proposed by Nix (1991): megathermal climate (MAT ≥ 22°C, mean annual precipitation (MAP > 549 mm); mesothermal climate (MAT range: > 14-22°C, MAP > 549 mm); microthermal climate (MAT ≤ 14°C, MAP range: 719-3000 mm). ...
... These results suggest that species from the different Nothofagus subgenera lived in mesothermal climates and this is further confirmed by our LMA results. Using the equation given in Peppe et al. (2011), we obtained MAT = 17.3°C (SE = AE 4.0°C) and using that of Hinojosa et al. (2011), MAT = 17.4°C (SE = AE 2.3°C). These two results indicate that the MAT was 11.3-11.4°C ...
... Additionally, there are reports of a growth-promoting endophytic strain that, under the influence of a hormonal imbalance of indole acetic acid and brassinosteroids, can transform into a biotrophic pathogen (Yousaf et al., 2021). to temperature gradients to understand their ecological and evolutionary importance (Peppe et al., 2011;Nicotra et al., 2011). Royer & Wilf (2006) hypothesized that toothed leaves increase sap flow, providing nutrients and other solutes to emerging and young leaves. ...
Background
The leaves of Serjania erecta Radlk (Sapindaceae) are renowned in ethnobotany for their medicinal properties and are significant as a medicinal resource for traditional Brazilian communities. As necrotic spots are common on these leaves, indicating interaction with phytopathogenic fungi, it was hypothesized that biotrophic fungal species colonize the leaf tissues of S. erecta .
Methods
To test this hypothesis, we employed standard techniques in plant anatomy, which enabled us to investigate the interaction of fungal structures with plant tissues and describe the morphoanatomical and histochemical characteristics of the epidermis and limbus of S. erecta .
Results
The anatomical analysis showed the existence of leaf teeth on the leaf tips. Additionally, hyphae, conidiospores, and spores of Bipolaris/Curvularia species were detected on the adaxial epidermis. Moreover, melanized microsclerotia were found in glandular areas of the leaf teeth and the phloem, providing evidence of biotrophic behavior. The hypothesis that biotrophic phytopathogenic fungi interact with S. erecta leaf tissues was confirmed, despite the presence of many bioactive compounds (such as flavonoids, alkaloids, and essential oils), as evidenced by histochemical analyses. The presence of tector, glandular, and scabiform trichomes on the leaf teeth and epidermis was also revealed. This study presents, for the first time, the synthesis of essential oils and alkaloids in the leaves of S. erecta . Additionally, it investigates previously unexplained aspects of the anatomy and histochemistry of the species, as well as its interaction with resident microorganisms. Therefore, it is recommended that future research focus on extracting and characterizing the oils and alkaloids of S. erecta , as well as exploring other aspects related to its microbiome and its relationship.
... The amount of carbon that leaves absorb during photosynthesis is directly related to the total biomass produced by grapevines. The physiological activity of leaves is influenced by several factors, such as size, age, climatic conditions, general characteristics of the terroir, and genetic differences (Peppe et al., 2011;Tozer et al., 2015). This activity, in turn, affects the total leaf area on grapevines, yield, and biochemical processes during the ripening period. ...
The aim of this study was to examine the impact of leaf water potential and defoliation treatments on the physical properties of grape berries. The research was conducted over two consecutive years (2019-2020) using ‘Merlot’/41B graft combination grapevines grown in the Chateau Kalpak vineyards located in Tekirdağ, Şarköy. The experiment involved four distinct water stress levels (S0, S1, S2, and S3), which were determined based on leaf water potential measurements. These stress levels were subjected to different irrigation levels. Additionally, defoliation treatments were applied, including Control (C), Full Window (FW), Right Window (RW), and Left Window (LW). The results showed that the effects of water stress and defoliation treatments on berry physical properties were statistically insignificant. However, in the second year of the study, the FW treatment was observed to have led to changes in the desired direction for grapevines. This was likely due to the cumulative decrease in water reserves caused by reduced precipitation over multiple years, making the effects of FW treatment more prominent. Moreover, the study found that both current and past vegetation period conditions influence vine production year, leaf water potentials (Ψleaf), and stress levels. Finally, the data revealed that berry weight and % dry weight increased with higher stress levels.
... Deeply lobed leaves are a strong adaptation to environmental stress, and they can affect the light capture ability of plants as well as their resistance to temperature stress, water stress and strong winds, regulate leaf surface temperature and increase ventilation permeability (Kidner and Umbreen 2010;Nicotra et al. 2011). Compared with entire-or serrated-leaf plants, deeply lobed-leaf plants seem to be better adapted to environmental stress and have higher photosynthetic efficiency and higher plant yield (Peppe et al. 2011). In practice, the shape of the leaves is easy to recognize in the early stages of seedlings. ...
Key messageBrLMI1is a positive regulatory factor of leaf lobe formation in non-heading Chinese cabbage, and cis-regulatory variations lead to the phenotype of lobed or entire leaf margins.
Abstract Leaves are the main consumed organ in leafy non-heading Chinese cabbage (Brassica rapa L. ssp. chinensis Makino), and the shape of the leaves is an important economic trait. However, the molecular regulatory mechanism underlying the lobed-leaf trait in non-heading Chinese cabbage remains unclear. Here, we identified a stable incompletely dominant major locus, qLLA10, for lobed leaf formation in non-heading Chinese cabbage. Based on map-based cloning strategies, BrLMI1, a LATE MERISTEM IDENTITY1 (LMI1)-like gene, was predicted as the candidate gene for qLLA10. Genotyping analysis showed that promoter variations of BrLMI1 in the two parents are responsible for elevating the expression in the lobed-leaf parent and ultimately causing the difference in leaf shape between the two parents, and the promoter activity of BrLMI1 was significantly affected by the promoter variations. BrLMI1 was exclusively localized in the nucleus and expressed mainly at the tip of each lobe. Leaf lobe development was perturbed in BrLMI1-silenced plants produced by virus-induced gene silencing assays, and ectopic overexpression of BrLMI1 in Arabidopsis led to deeply lobed leaves never seen in the wild type, which indicates that BrLMI1 is required for leaf lobe formation in non-heading Chinese cabbage. These findings suggested that BrLMI1 is a positive regulatory factor of leaf lobe formation in non-heading Chinese cabbage and that cis-regulatory variations lead to the phenotype of lobed or entire leaf margins, thus providing a theoretical basis for unraveling the molecular mechanism underlying the lobed leaf phenotype in Brassica crops.
... (Ghazanfar & Edmondson, 2013). Differences in habitat can be reflected in morphological features, so different environmental conditions cannot be ignored in population diversity studies (Thorpe, 1987;Peppe et al., 2011). Elevation is one of the important environmental factors that affect population differentiation and genetic diversity. ...
We conducted a comprehensive study on the diversity of Silene aucheriana Boiss. populations by analyzing both morphological data and nrDNA ITS sequences. Maximum parsimony and Bayesian methods on representative material from 15 populations throughout Iran demonstrated that they did not form a monophyletic group. Strong positive correlation occurred between epipetalous filaments length to claw (EFLC), basal leaf length (BLL), basal leaf width (BLW), and plant height (PLH) with elevation. While negative correlation achieved between anthophore length (AnL) with the average air temperature and rainfall. Canonical Correspondence Analysis (CCA) showed that most morphological traits were more correlated to elevation than to average rainfall and temperature. Multivariate analysis of morphological traits with ITS analysis displayed a slight divergence between two types of regions based on their elevation. Izvleček Izvedli smo celovito študijo o raznolikosti populacij vrste Silene aucheriana Boiss. z analizo morfoloških meritev in zaporedij ITS nrDNA. Največja parsimonija in statistične metode po Bayesu na reprezentativnem materialu iz 15 populacij po vsem Iranu so pokazale, da ne tvorijo monofiletične skupine. Ugotovili smo močno pozitivno korelacijo med dolžino epipetalnih filamentov in žebice (EFLC), dolžino spodnjih listov (BLL), širino spodnjih listov (BLW) in višino rastline (PLH) z nadmorsko višino. Negativno korelacijo smo ugotovili med dolžino antofore (AnL) in povprečno temperaturo zraka ter količino padavin. Kanonična korespondenčna analiza (CCA) je pokazala, da je večina morfoloških lastnosti bolj povezana z nadmorsko višino, kot pa s povprečno količino padavin in temperaturo. Multivariatna analiza morfoloških lastnosti z analizo ITS je pokazala rahlo odstopanje med dvema skupinama regij glede na njihovo nadmorsko višino.
... There are several studies that support our observations regarding the relationships between leaf size, aspect ratio, temperature, and rainfall. Most notably, the data observed follow similar trends seen in previously collected paleoclimatic evidence [23,24]. More modern evidence also follows these trends such as Wright et. ...
This study utilized the Fourier-based method to analyze the morphology of over 4000 leaves from more than 190 accessions selected from the Givaudan Citrus Variety Collection at the University of California Riverside, one of the world’s most diverse collections of citrus and closely related genera. Our analysis revealed significant variations in leaf morphology among the major citrus species groups, and hybrid varieties produced through breeding exhibited intermediate leaf morphology compared to their parental citrus species. We found a positive correlation between leaf area in native citrus species and temperature in lower tropical latitudes, while negative/positive associations between aspect ratio and temperature/rainfall were also observed, respectively. These results suggest that citrus leaves may have evolved into larger but thinner leaves to increase their photosynthetic capacity per unit area while maintaining water balance by reducing water loss through transpiration. Our analysis also indicates that the existing biodiversity observed in citrus species can be attributed to their migrations across the foothills of the Himalayas, southward to the islands of Indonesia, and northward to the islands of Japan. Our study supports the hypothesis that citrus species have adapted to warm areas lacking extreme daily and nightly temperatures, where a large number of species of origin are found. Overall, this study presents a promising approach to investigate the morphological variation in citrus leaves, which could potentially aid in the selection and breeding of citrus cultivars with superior physiological traits and deepen our understanding of citrus diversity.
... Methods based on leaf physiognomy utilize the correlation between the architecture of leaves and climatic variables. As leaf size and shape are highly sensitive to moisture availability (Givnish, 1984;Peppe et al., 2011;Spicer et al., 2021), fossil leaf architecture can be related to precipitation using univariate methods such as Leaf Area Analysis (LAA) (Wilf et al., 1998). The Climate Leaf Analysis Multivariate Program (CLAMP) (Wolfe, 1993(Wolfe, , 1995 combines multiple leaf traits, including leaf area, leaf shape, and margin state (i.e., toothed or untoothed), to provide estimates of annual and seasonal precipitation (Spicer et al., 2021). ...
Earth's hydrological cycle is expected to intensify in response to global warming, with a “wet‐gets‐wetter, dry‐gets‐drier” response anticipated over the ocean. Subtropical regions (∼15°–30°N/S) are predicted to become drier, yet proxy evidence from past warm climates suggests these regions may be characterized by wetter conditions. Here we use an integrated data‐modeling approach to reconstruct global and zonal‐mean rainfall patterns during the early Eocene (∼56–48 million years ago). The Deep‐Time Model Intercomparison Project (DeepMIP) model ensemble indicates that the mid‐ (30°–60°N/S) and high‐latitudes (>60°N/S) are characterized by a thermodynamically dominated hydrological response to warming and overall wetter conditions. The tropical band (0°–15°N/S) is also characterized by wetter conditions, with several DeepMIP models simulating narrowing of the Inter‐Tropical Convergence Zone. However, the latter is not evident from the proxy data. The subtropics are characterized by negative precipitation‐evaporation anomalies (i.e., drier conditions) in the DeepMIP models, but there is surprisingly large inter‐model variability in mean annual precipitation (MAP). Intriguingly, we find that models with weaker meridional temperature gradients (e.g., CESM, GFDL) are characterized by a reduction in subtropical moisture divergence, leading to an increase in MAP. These model simulations agree more closely with our new proxy‐derived precipitation reconstructions and other key climate metrics and imply that the early Eocene was characterized by reduced subtropical moisture divergence. If the meridional temperature gradient was even weaker than suggested by those DeepMIP models, circulation‐induced changes may have outcompeted thermodynamic changes, leading to wetter subtropics. This highlights the importance of accurately reconstructing zonal temperature gradients when reconstructing past rainfall patterns.
... (Zhang et al., 2017). Previous studies have indicated that traits can affect speciation and extinction because they determine how species interact with their environment and with other species (Boyce et al., 2009;Peppe et al., 2011;Sundue et al., 2015). Leaf architecture and morphology play crucial functional roles in plant ecophysiology, and innovations in leaf morphology among ferns have been proposed to be linked with major radiations (Janssen and Schneider, 2005;Kreier et al., 2008b;Wang et al., 2012;McHenry and Barrington, 2014;Sanchez-Baracaldo and Thomas, 2014). ...
Intercontinental disjunct distributions can arise either from vicariance, from long-distance dispersal, or through extinction of an ancestral population with a broader distribution. Tectariaceae s.l., a clade of ferns in Polypodiales with ca. 300 species mainly distributed in the tropics and subtropics, provide an excellent opportunity to investigate global distribution patterns. Here, we assembled a dataset of eight plastid markers and one nuclear marker of 636 (92% increase of the earlier largest sampling) accessions representing ca. 210 species of all eight genera in Tectariaceae s.l. (Arthropteridaceae, Pteridryaceae, and Tectariaceae s.s.) and 35 species of other families of eupolypods Ⅰ. A new phylogeny is reconstructed to study the biogeography and trait-associated diversification. Our major results include: (1) a distinct lineage of Tectaria sister to the rest of the American Tectaria is identified; (2) Tectariaceae s.l., and the three families: Arthropteridaceae (Arthropteris), Pteridryaceae (Draconopteris, Malaifilix, Polydictyum, Pteridrys), and Tectariaceae s.s. (Hypoderris, Tectaria, and Triplophyllum), might have all originated in late Cretaceous; (3) only five intercontinental dispersals occurred in Pteridryaceae and Tectariaceae s.s. giving rise to their current intercontinental disjunction; (4) we provide the second evidence in ferns that a long-distance dispersal between Malesia and Americas during the Paleocene to Eocene led to the establishment/origin of a new genus (Draconopteris); and (5) diversification rate of each state of leaf dissection is different, and the lowest is in the simple-leaved taxa.
... In the last decade, a growing body of studies suggested that intraspecific trait variations could not be ignored (Albert et al., 2010;Auger and Shipley, 2013;Niu et al., 2020). Climate, soil, altitude, aspect, illumination, and many other environmental factors all cause intraspecific trait variations (Hultine and Marshall, 2000;McDonald et al., 2003;Peppe et al., 2011). Plants of a certain species growing in diverse environments may present large intraspecific trait variations (Liu et al., 2023). ...
When measuring plant functional traits across geomorphologies, 5–10 healthy individuals of a plant species are commonly sampled. However, whether more individuals should be sampled in habitat-heterogeneous karst vegetation remains unknown. In this study, two dominant tree species (Clausena dunniana and Platycarya strobilacea) in karst evergreen and broadleaved mixed forests in Southwestern China were selected. On the basis of a large quantity of individuals of the two species grown in different peak clumps and slope positions, variations of 10 morphological traits in the two species were statistically analyzed. The suggested sampling number of individuals, which could mostly represent the common trait characteristics, was further explored. All traits showed significant differences between the two species (P < 0.05). The traits of P. strobilacea displayed larger intraspecific variations than those of C. dunniana, except for twig dry matter content. The bark thickness (BT), leaf area (LA), and specific leaf area (SLA) of C. dunniana and the BT, SLA, LA, leaf tissue density, and bark tissue density of P. strobilacea presented large intraspecific variations. Most traits exhibited significant differences between peak clumps and/or among slope positions (P < 0.05). Random sampling analysis indicated that the suggested sampling numbers of individuals for the 10 traits are 6–23 in C. dunniana and 9–29 in P. strobilacea. The common accepted sample size in normal geomorphologies is not sufficiently large in most cases. Larger sample sizes are recommended for traits, such as SLA, BT, and LA, with larger intraspecific variations. Therefore, under sufficient labor, material, and time, more individuals should be sampled when measuring plant functional traits in habitat-heterogeneous karst vegetation.
... Leaf shape variations mainly involve in the shape of the leaf margins, including entire, serrated or deeply lobed. Compared with entire-or serrated-leaf plants, deeply lobed-leaf plants seem to be better adapted to environmental stress due to the optimized canopy structure (Peppe et al. 2011). In practice, as an ideal indicator trait, leaf lobes can be used in crops breeding, especially in hybrid production and purity identi cation (Tu et al. 2013). ...
Leaves are the main consumed organ in leafy non-heading Chinese cabbage ( Brassica rapa L. ssp. chinensis Makino), and the shape of the leaves is an important economic trait. However, the molecular regulatory mechanism underlying lobed-leaf trait in non-heading Chinese cabbage remains unclear. Here, we identified a stable incompletely dominant major locus qLLA10 for lobed leaves formation in non-heading Chinese cabbage. Based on map-based cloning strategies, BrLMI1 , a LATE MERISTEM IDENTITY1 ( LMI1 )-like gene, was predicted as the candidate gene for qLLA10. Genotyping analysis showed that promoter variations of BrLMI1 in two parents are responsible for elevating the expression in the lobed-leaf parent and ultimately causing the alternation in leaf shape between the two parents, and the promoter activity of BrLMI1 was significantly affected by the promoter variations. BrLMI1 was exclusively localized in the nucleus and expressed mainly at the tips of each lobe. Leaf lobe development was perturbed in BrLMI1 -silenced plants produced by virus-induced gene silencing assays, and ectopic overexpression of BrLMI1 in Arabidopsis led to deeply lobed leaves never seen in the wild type, which indicates that BrLMI1 is required for leaf lobe formation in non-heading Chinese cabbage. These findings suggested that BrLMI1 is a positive regulatory factor of leaf lobe formation in non-heading Chinese cabbage and that cis-regulatory variations lead to the phenotype of lobed or entire leaf margins, thus providing the theoretical basis for unraveling the molecular mechanism underlying lobed leaves phenotype in Brassica crops.
... Many plant traits, both response and effect traits, are related to environmental conditions, although the relations are usually weak at the global scale (Moles et al., 2014;Díaz et al., 2016;Wright et al., 2017;Baird et al., 2021). For example, leaf size tends to be smaller at higher latitudes, but larger at wetter or warmer sites (Peppe et al., 2011;Wright et al., 2017). Leaf nitrogen and phosphorus concentrations decrease toward the equator generally as average temperature and growing season length increase (Reich & Oleksyn, 2004). ...
Plant flammability is an important driver of wildfires, and flammability itself is determined by several plant functional traits. While many plant traits are influenced by climatic conditions, the interaction between climatic conditions and plant flammability has rarely been investigated.
Here, we explored the relationships among climatic conditions, shoot‐level flammability components, and flammability‐related functional traits for 186 plant species from fire‐prone and nonfire‐prone habitats.
For species originating from nonfire‐prone habitats, those from warmer areas tended to have lower shoot moisture content and larger leaves, and had higher shoot flammability with higher ignitibility, combustibility, and sustainability. Plants in wetter areas tended to have lower shoot flammability with lower combustibility and sustainability due to higher shoot moisture contents. In fire‐prone habitats, shoot flammability was not significantly related to any climatic factor.
Our study suggests that for species originating in nonfire‐prone habitats, climatic conditions have influenced plant flammability by shifting flammability‐related functional traits, including leaf size and shoot moisture content. Climate does not predict shoot flammability in species from fire‐prone habitats; here, fire regimes may have an important role in shaping plant flammability. Understanding these nuances in the determinants of plant flammability is important in an increasingly fire‐prone world.
... K. septemlobus has the largest leaf area, LMA, and leaf N and the smallest leaf δ 13 C in the six tested species. Among these functional traits, the species with the large leaf size is known to be adapted to cold climate globally [33]. It is possible that the largest leaf area functioned well in the cold climate in the spring after snowmelt and this resulted in the positive reaction of K. septemlobus growth to snowmelt treatment. ...
Climate warming is advancing snowmelt timing in the spring at high latitudes. To predict tree growth in subboreal forests under warmer climates based on mechanistic understanding, it is important to assess how advancing snowmelt influences tree growth in the spring via ecophysiological changes in subboreal forests. In this study, we conducted a field manipulation experiment of snowmelt timing and investigated the response of tree growth, leaf functional traits, and bud-burst phenology in the spring for the seedlings of six dominant tree species in subboreal forests. We found that the spring growth of only one species (Kalopanax septemlobus) out of six species responded positively to advancing snowmelt. Among the leaf functional traits (leaf mass per area, leaf nitrogen content, leaf δ13C value, leaf dry matter content, and leaf area) and bud-burst phenology, only the increase in leaf area was linked to the enhanced shoot growth of K. septemlobus. The significant change in K. septemlobus might be associated with its ecological characteristics to prefer regeneration in canopy gaps. These results indicate that advancing snowmelt under warmer winters can be beneficial for tree species that can plastically develop leaf area in Japanese subboreal forests.
... These leaf traits probably reflect both climatic dependencies with a geographical west-east gradient (continentality) and altitude ( Figure 8). Changes in BL leaf segments, margin incision, and the number of teeth usually influence leaf surface area, stomatal conductance, transpiration, and thus leaf energy balance and temperature, representing adaptation to water-limited and/or climatically variable environments [183,184]. Since shape differences are mainly attributed to genomic differences in the R. auricomus complex, these different leaf shapes probably represent selective advantages in their respective environments, for example, large non-dissected BL taxa along relatively waterrich but rather continental streamside habitats (e.g., R. cassubicifolius, R. ×pseudocassubicus), or strongly dissected BL taxa in less continental but rather dry anthropogenic meadows in Central-Eastern Europe (e.g., R. notabilis, R. ×variabilis). Interestingly, garden experiments with different levels of soil nutrients did not reveal changes in leaf shape, and different light treatments influenced only the size of plants and the number of leaves but not the shape of BL [161]. ...
Plant species complexes represent a particularly interesting example of taxonomically complex groups (TCGs), linking hybridization, apomixis, and polyploidy with complex morphological patterns. In such TCGs, mosaic-like character combinations and conflicts of morphological data with molecular phylogenies present a major problem for species classification. Here, we used the large polyploid apomictic European Ranunculus auricomus complex to study relationships among five diploid sexual progenitor species and 75 polyploid apomictic derivate taxa, based on geometric morphometrics using 11,690 landmarked objects (basal and stem leaves, receptacles), genomic data (97,312 RAD-Seq loci, 48 phased target enrichment genes, 71 plastid regions) from 220 populations. We showed that (1) observed genomic clusters correspond to morphological groupings based on basal leaves and concatenated traits, and morphological groups were best resolved with RAD-Seq data; (2) described apomictic taxa usually overlap within trait morphospace except for those taxa at the space edges; (3) apomictic phenotypes are highly influenced by parental subgenome composition and to a lesser extent by climatic factors; and (4) allopolyploid apomictic taxa, compared to their sexual progenitor, resemble a mosaic of ecological and morphological intermediate to transgressive biotypes. The joint evaluation of phylogenomic, phenotypic, reproductive, and ecological data supports a revision of purely descriptive, subjective traditional morphological classifications.
... However, many of these temperature ranges of the fossil estimates and the cooler Southeast Asian temperatures overlap. In addition, leaf physiognomic approaches, including those used to estimate temperature at Blue Rim and for the Green River flora, tend to underestimate paleotemperature (Kowalski and Dilcher 2003;Peppe et al. 2011;Spicer et al. 2011;Royer et al. 2012). Even though the temperature estimates of the fossil floras are cooler than the tropical climate inhabited by extant Tetramelaceae, other components (e.g., Illigera, Hernandiaceae [Manchester and O'Leary 2010], Iodeae, Icacinaceae [Allen et al. 2015]) of the fossil floras have tropical nearest living relatives today. ...
... Plants can modify their phenotype in response to environmental changes, which is known as phenotypic plasticity (Gratani 2014). Since the role of leaves is intrinsically connected to the environment, at the interface between the habitat and organism (Peppe et al. 2011), leaves are influenced by environmental changes and, therefore, their responses serve as ecological indicators of the influence of abiotic conditions on plant growth in heterogeneous environments (Chagas et al. 2008). ...
This study investigated the foliar plasticity in Schwartzia brasiliensis in restinga formations (shrub and shrub-tree restinga) in southern Brazil. In each area, 10 individuals were selected and leaves in sunlight were collected for an analysis of functional leaf traits, including: fresh and dry leaf mass, leaf area, specific leaf area, succulence, stem diameter, plant height and tissue thickness. Environmental variables were measured considering soil mineral nutrition, water availability and photosynthetically active radiation. Phenotypic plasticity index was calculated for studied attribute. We compared means with a Student’s t-test and the weight of environmental variables with a PCA. Results showed that the main leaf traits that differentiated the populations were leaf dry mass, specific leaf area, lamina thickness and plant height, while the main predictor environmental variables were gravimetric humidity, solar radiation, soil CEC, phosphorus content and salinity. In the shrub restinga, there is greater investment in mechanical support as a water saving strategy due to greater exposure to solar radiation. In the shrub-tree restinga, there is greater investment in photosynthetic production, since the shade provided by the treetops of other species attenuates the radiation effect. Despite the low plastic potential, the populations present structural adjustments that respond to the environmental heterogeneity.
... Temperature is one of the critical drivers of leaf size and shape worldwide, generating giant leaves that have fewer, smaller teeth in tropical plants, and tiny ones with more numerous teeth in deserts (Peppe et al., 2011). Aridity limits leaf size as the risk of overheating during daytime maximum temperatures increases as they grow larger. ...
Extreme lands lying at the edges of at least one abiotic gradient permit the survival of extremely few species. These so-called extremophile species (literally loving “philos” the extremes) harbour a unique reservoir of genetic and biochemical adaptations that has always attracted human curiosity. Previous studies have shown a high degree of species-specificity for plant adaptation to hostile biomes, thus explaining that successful transfers of protective mechanisms to crops remain scant. However, generic adaptive strategies may also exist. In this context, I propose to carry out a comprehensive approach from the ecosystem to the metabolites to investigate the biochemical adjustments of extremophile plant species from the Atacama Desert, the driest non-polar desert on earth. Plants were collected in their natural environment that spans an elevation gradient from 2500 to 4500m. Multiple metabolomic approaches were combined with machine learning to unveil a generic toolbox for plant resilience to harsh conditions. Subsequently, reaction and pathway enrichment analyses identified genetic legacies underlying convergent biochemical strategies selected through evolution. Finally, the role of positive interactions with the cactus Maihueniopsis camachoi in the adaptation of various plant species to harsh environments was explored. Results yielded a better mechanistic understanding of facilitation processes and the discovery of an intriguing set of metabolites able to predict the interaction status. Overall, while this study provided significant insights into our comprehension of adaptive mechanisms underlying plant resilience to extreme climates, our multi-species approach foreshadows promising studies and discoveries in agronomy and ecology.
... Novel quantitative terrestrial climate proxies have been introduced, improved, and/or expanded in recent years, providing more accurate estimates of MAT and MAP as well as additional parameters like temperature and precipitation seasonality. Examples of such quantitative proxies include carbonate clumped isotope paleothermometry (e.g., Eiler, 2011), phyllosilicate crystallization temperature (e.g., Andrezejewski, 2018), paleosol geochemistry (e.g., Sheldon and Tabor, 2009;Hyland et al., 2015;Hyland and Sheldon, 2016), leaf physiognomy (e.g., Spicer et al., 2009;Peppe et al., 2011), and organic lipid-based paleothermometers like TEX 86 (e.g., Tierney and Tingley, 2014;Polik et al., 2018). Each of these proxies formed in unique environmental and depositional settings and have important limitations and caveats when interpreting their results. ...
... The lobed character is easy to identify and observe, and is inherited stably, which is often used as an ideal morphological marker in leaf mustard breeding. The lobed-leaf character of B. juncea has strong adaptation on chilling stress and water stress, and it can resist high temperature and increase ventilation [3][4][5]. Furthermore, leaf mustard is used as a pickling material, and the petiole accounts for a higher proportion of the whole leaf in lobed leaves, which are beneficial for post-harvest processing. Thus, a better understanding of the molecular regulatory mechanism of lobed leaves in mustard will contribute to the leaf shape and its utilization in production. ...
The shape of the leaf is the primary phenotype which determines the commercial value of leaf mustard (Brassica juncea). However, there arefew reports on the lobed-leaf gene of B. juncea, and the molecular regulatory mechanisms underlying leaf margin formation are unknown. In this study, an F2 population derived from ‘MN001’ and ‘MU056’ was constructed. Genetic analysis revealed that the lobed-leaf trait is controlled by a major gene, and lobed leavesare dominant compared to round leaves. The GradedPool-Seq analysis combined with the re-sequencing results of parents identified a major interval on chromosome 10 of B. juncea’s genome A. The BjLMI1 gene (BjuA040054) was confirmed to be a candidate gene by gene ontology (GO) analysis, and it is homologous with LMI1 and encodes HD-Zip protein ATHB-51. A base substitution was observed in the conserved domain, and a 63 bp fragment deletion was found in the exon region between the two parents in the CDs region. The expression of BjLMI1 was significantly higher in the lobed-leaf parent than in the round-leaf parent. These findings provide insights into the molecular mechanism underlying leaf margin formation and will be valuable in the development of an ideal leaf shape in B. juncea.
... Evidence supports that leaf morphology variation has adaptive significance linked with climate (Peppe et al. 2011), especially with latitude, altitude, temperature, and rainfall (Ackerly et al. 2002, Byars et al. 2007, Mediavilla et al. 2012. However, the physiological ecology of Q. saponaria along a latitudinal gradient has received little attention. ...
Quillaja saponaria is a sclerophyllus evergreen tree species distributed from 30° to 38° S in Central Chile. In this wide distribution it is expected that the species exhibits phenotypic plasticity in the morphology of leaves associated to climate variation; however, the information on this topic is still scarce.We studied leaf phenotypic variation and its relationship with temperature, precipitation, and aridity in 85 stands of Q. saponaria throughout the natural distribution of the species. The results show that the basal diameter of petiole, the number of secondary veins, and the basal diameter of the principal vein increased with precipitation and decreased with aridity, while the length, basal diameter and the
relative length of the petiole decreased with temperature. This confirms that phenotypic variation for foliar characters in Q. saponaria is related to climatic variables indicating an adapting capability of the species to the wide range of environmental conditions in which grows.
... collecting the true proxy's samples, sample analysis and data processing (in-situ measurements), different scales of data calibration, modeling assumptions and mathematical errors, location. The other probable factors include the errors and bias associated to the ambiguity of character definitions, use of discontinuous variables, weak correlations between climate and some character states (Peppe et al., 2011;Wei et al., 2021). These sources of error tend to impact the quality of reconstructed climate model where few of them are not in human controls and thus, lead to model inaccuracy. ...
The sediments have been a ubiquitous archive for the paleoclimate reconstruction while the marine sediments are considered to be serene and mostly undisturbed from the anthropogenic encroachments. Unlike continental records, the deep-sea sediments elucidated the evidence of at least 50 glacial and interglacial stages during the Quaternary Period and thus proved its applicability in quaternary climate reconstruction. The geochemical variations in the marine sediments are often used as proxy to decode the past productivity, redox, weathering and provenance changes as a function of past climate and oceanographic perturbations. The geochemical behaviour of the elements in sedimentary environment primarily relies on ionic potential along with redox potential and pH which leads to mobility and enrichment of selected elements and thus acting as potential evidence for ambient temporal changes. The present chapter aims to provide an overview of frequently used geochemical proxies and their applicability. Further the chapter also tries to provide significance of statistical and machine learning approaches on the geochemical datasets in understanding the climatic processes that led to changes in the geochemical variability.
... This result is significantly different from the numerical value of the alpine oak provided in ref. [13], because the leaf shape of Q. pannosa is a special superellipse with a mean leaf ellipticalness index greater than unity [34][35][36], which is larger than those of the two Photinia taxa examined in this study. Since leaf shape is found to be closely related to climatic factors [18,37], it would be worth studying the link between the m p and climate for some widely distributed plants in the future. ...
Leaf shape and size can vary between hybrids and their parents. However, this has seldom been quantitatively tested. Photinia × fraseri is an important landscaping plant in East Asia as a hybrid between evergreen shrubs P. glabra and P. serratifolia. Its leaf shape looks like that of P. serratifolia. To investigate leaf shape, we used a general equation for calculating the leaf area (A) of broad-leaved plants, which assumes a proportional relationship between A and product of lamina length (L) and width (W). The proportionality coefficient (which is referred to as the Montgomery parameter) serves as a quantitative indicator of leaf shape, because it reflects the proportion of leaf area A to the area of a rectangle with L and W as its side lengths. The ratio of L to W, and the ellipticalness index were also used to quantify the complexity of leaf shape for elliptical leaves. A total of >4000 leaves from P. × fraseri and P. serratifolia (with >2000 leaves for each taxon) collected on a monthly basis was used to examine: (i) whether there is a significant difference in leaf shape between the two taxa, and (ii) whether there is a monotonic or parabolic trend in leaf shape across leaf ages. There was a significant difference in leaf shape between the two taxa (p < 0.05). Although there were significant differences in leaf shape on a monthly basis, the variation in leaf shape over time was not large, i.e., leaf shape was relatively stable over time for both taxa. However, the leaf shape of the hybrid was significantly different from its parent P. serratifolia, which has wider and more elliptical leaves than the hybrid. This work demonstrates that variations in leaf shape resulting from hybridization can be rigorously quantified and compared among species and their hybrids. In addition, this work shows that leaf shape does not changes as a function of age either before or after the full expansion of the lamina.
... Using daily meteorology from a GCM of the late Carboniferous (GENESIS v3) under a Glacial (low-CO2) and an Inter-glacial (high-CO2) scenario, we found that simulated sapwood dysfunction slowed plant water use and reduced carbon storage. This inhibition occurred particularly in plants with high maximum stomatal conductance and high stem vulnerability Introduction Morphological features of plant fossils are a well-established source of information about ancient Earth (McElwain, 1998;Royer, 2001;Beerling and Royer, 2002;Franks and Beerling, 2009;Peppe et al., 2011). For example, measurements of leaf fossil characteristics have been used to infer properties of ancient plant physiology (Boyce et al., 2009;Franks and Beerling, 2009;Brodribb and Feild, 2010;Nicotra et al., 2011;Haworth and Raschi, 2014;Montañez et al., 2016;Wilson et al., 2017Wilson et al., , 2020Boyce and Zwieniecki, 2019;White et al., 2020) and greenhouse gas concentrations (Woodward, 1987;McElwain, 1998;Beerling and Royer, 2002;Wagner et al., 2002;Finsinger and Wagner-Cremer, 2009;Franks and Beerling, 2009;Steinthorsdottir et al., 2011;Montañez et al., 2016;Richey et al., 2020Richey et al., , 2021. ...
The evolution of woody stems approximately 400 mya (middle Paleozoic) facilitated the expansion of plants and has likely affected carbon and water budgets across much of the terrestrial surface since that time. Stems are a carbon cost/sink and limit water transport from soil to leaves as it must pass through specialized xylem tissue. While leaf fossils have provided a wealth of quantitative data, including estimates of plant water fluxes utilizing biophysically based models, fossil-informed models integrating stem and leaf physiology are lacking. Integrated stem-leaf physiology may distinguish successors to ecological catastrophes like the end of the Late Paleozoic Ice Age (LPIA). The documented collapse of LPIA tropical forests provides an opportunity to assess the importance of woody stems as a key to understanding differences in survivorship among common plant taxa from the Carboniferous to the Permian. Here, we present an analysis of the limits to leaf water supply and plant function for Paleozoic forest plant types due to (1) cavitation-induced embolism and xylem blockage and (2) insufficient sapwood water transport capacity.—collectively defined here as sapwood dysfunction. We first present a modified ecosystem process model (Paleo-BGC+) that includes sapwood dysfunction. Paleo-BGC + is parameterized using measurements obtainable from fossil xylem and therefore applicable to both modern and ancient ecosystems. We then assess the effect of sapwood dysfunction on ecosystem processes based on previously published fossil leaf measurements and a new fossil xylem dataset for plant types present in the Late Paleozoic. Using daily meteorology from a GCM of the late Carboniferous (GENESIS v3) under a Glacial (low-CO2) and an Inter-glacial (high-CO2) scenario, we found that simulated sapwood dysfunction slowed plant water use and reduced carbon storage. This inhibition occurred particularly in plants with high maximum stomatal conductance and high stem vulnerability to embolism. Coincidentally, plants with these traits were predominantly reduced or missing from the fossil record from the Carboniferous to the Permian. Integrating stem and leaf physiology may improve the fidelity of model representations of soil-to-atmosphere water transport through plants, simulations of long-term climate phenomena like the LPIA, and ecosystem projections under future climate change.
... LA and SLA determine a plant's capacity to capture light (Poorter et al., 2009), leaf heat exchange (Wright et al., 2017), and the length of the water pathway through leaves (Kang et al., 2021) -all of which are closely related to transpiration and photosynthesis. Previous studies have focused primarily on the patterns of LA and SLA along environmental gradients (Peppe et al., 2011;Wright et al., 2017). For example, small-leaved species prevail in dry, hot, sunny environments or at high elevations (Wright et al., 2017). ...
Stomatal conductance (gs) of all coexisting species
regulates transpiration in arid and semiarid grasslands prone to droughts.
However, the effect of drought stress on canopy conductance (Gs) is
debated, and the interactive effects of abiotic and biotic constraints on
Gs remain poorly understood. Here, we used 18O enrichment above the
source water (Δ18O) of leaf organic matter as a proxy for Gs in order to
increase the understanding of these effects. Three grassland transects were
established along aridity gradients on the Loess Plateau (LP), the Inner Mongolian
Plateau (MP), and the Tibetan Plateau (TP), which differ with respect to solar radiation and
temperature conditions. Results showed that Gs consistently decreased
with increasing aridity within transects. Gs on the TP was lower than that
on the other two plateaus for a given level of aridity due to low
temperature and high radiation. The primary determinant of drought stress on
Gs was soil moisture (SM) on the LP and MP, whereas it was the vapor pressure deficit
(VPD) on the TP. Solar radiation exhibited a consistently negative effect on
Gs via drought stress within transects, while temperature had negative
effects on Gs on the TP but no effect on the LP or MP. Adding the
interaction of leaf area and abiotic factors increases the percentage of
explained variability in Gs by 17 % and 36 % on the LP and MP,
respectively, although this is not the case on the TP, where the climate exerts an overwhelming effect.
These results highlight the need to integrate multiple stressors and plant
properties to determine spatial variability in Gs.
... For ecometrics to work a trait-environment relationship needs to be identified through direct observations or identifying correlations based on underlying mechanical function. Examples of widely applied ecometrics based on observations are the relationship of gross leaf (Bailey and Sinnott, 1915;Greenwood et al., 2004;Peppe et al., 2011) and tooth (Liu et al., 2012;Fortelius et al., 2016;Oksanen et al., 2019) morphology to climate and body size to temperature (Hunt and Roy, 2006;L. Trip et al., 2014;Audzijonyte et al., 2020). ...
Humans are changing the Earth. What is unknown is how biotic communities and ecosystems will react to this change on both short and long timescales. The fossil record can provide us with a means of investigating ecosystem responses to long-term climatic fluctuations which can act as baselines for future anthropogenic induced change. How we utilize the fossil record is therefore of critical Importance. The high spatial and temporal resolution of the planktonic foraminifera fossil record provides an ideal system to investigate ecosystem responses to climatic fluctuations at multiple scales and levels. The primary objective of this thesis is to measure and understand the relationship between planktonic foraminifera and their environment, to enable a more biologically informative assessment of the fossil record. I created a diversity record of planktonic foraminifera through the Middle Eocene Climatic Optimum comprising of 22,800 individuals classified to three taxonomic levels and investigated the responses of these assemblages using effective diversity: a novel approach for Palaeogene and deep-time systems (Chapter 2). The results from this study show that analytical size fraction choice is a key determinant of diversity signals in deep-time and furthermore it is small species that maintain ecological function during transient climatic events. I then investigated a key component of these assemblages, Subbotina, using individual morphological and geochemical measurements to link their traits to the environment and assess their persistence through the climatic fluctuations of the Middle Eocene (Chapter 3). I found that longevity of Subbotina is a result of morphological and geochemical trait plasticity resulting in a wide ecological niche which in turn allowed for continued persistence and dominance through the Middle Eocene whilst other groups faltered. Next, I explored the relationship between geochemistry and morphology within a relatively recent system to understand the relationship between geochemistry, size, and genetically identified species (Chapter 4). The results showed that fine resolution geochemical analyses can be used to unpick the drivers of intraindividual variability. However, more work is needed to understand the drivers of geochemistry at the individual level which is possible using the methods I advocate and explore in this thesis. Together, these discoveries expand our understanding of how planktonic foraminifera communities are linked to their environment and demonstrate that by using the appropriate analytical approaches we can investigate this relationship in a more biologically meaningful way. Future studies on planktonic foraminifera will require the application of traitbased approaches through the integration of geochemistry, morphology, and diversity measurements to further our understanding of how past communities responded to climatic perturbations with an aim to inform our understanding of biotic responses to current and future anthropogenic change
... In addition to leaf serrations or teeth, leaf size varies considerably, with an over 100,000-fold difference in leaf size among species worldwide (Díaz et al., 2016;Wright et al., 2017). Similar to variation in teeth, leaf size varies with climate, with larger leaves generally found in wetter, warmer areas, the same zones where less-toothed leaves are found (Webb, 1968;Peppe et al., 2011;Chitwood and Sinha, 2016). For example, in a study of the Australian rainforest, leaves were found to be smaller with a reduction in rainfall (Webb, 1968). ...
Premise:
Leaf lobing and leaf size vary considerably across and within species, including among grapevines (Vitis spp.), some of the best-studied leaves. We examined the relationship between leaf lobing and leaf area across grapevine populations that varied in extent of leaf lobing.
Methods:
We used homologous landmarking techniques to measure 2632 leaves across 2 years in 476 unique, genetically distinct grapevines from five biparental crosses that vary primarily in the extent of lobing. We determined to what extent leaf area explained variation in lobing, vein length, and vein to blade ratio.
Results:
Although lobing was the primary source of variation in shape across the leaves we measured, leaf area varied only slightly as a function of lobing. Rather, leaf area increases as a function of total major vein length, total branching vein length, and vein to blade ratio. These relationships are stronger for more highly lobed leaves, with the residuals for each model differing as a function of distal lobing.
Conclusions:
For leaves with different extents of lobing but the same area, the more highly lobed leaves have longer veins and higher vein to blade ratios, allowing them to maintain similar leaf areas despite increased lobing. These findings show how more highly lobed leaves may compensate for what would otherwise result in a reduced leaf area, allowing for increased photosynthetic capacity through similar leaf size.
Accurately reconstructing large-scale palaeoclimate patterns from sparse local records is critical for understanding the evolution of Earth’s climate. Particular challenges arise from the patchiness, uneven spatial distribution, and disparate nature of palaeoclimatic proxy records. Geochemical data typically provide temperature estimates via transfer functions derived from experiments. Similarly, transfer functions based on the climatic requirements of modern taxa exist for some fossil groups, such as pollen assemblages. In contrast, most ecological and lithological data (e.g. coral reefs and evaporites) only convey information on broad climatic requirements. Historically, most large-scale proxy-based reconstructions have used either geochemical or ecological data, but few studies have combined multiple proxy types into a single quantitative reconstruction. Large spatial gaps in existing proxy records have often been bridged by simple averaging, without taking into account the spatial distribution of samples, leading to biased temperature reconstructions. Here, we present a Bayesian hierarchical model to integrate ecological data with established geochemical proxies into a unified quantitative framework, bridging gaps in the latitudinal coverage of proxy data. We apply this approach to the early Eocene climatic optimum (EECO), the interval with the warmest sustained temperatures of the Cenozoic. Assuming the conservation of thermal tolerances of modern coral reefs and mangrove taxa, we establish broad sea surface temperature ranges for EECO coral reef and mangrove sites. We integrate these temperature estimates with the EECO geochemical shallow marine proxy record to model the latitudinal sea surface temperature gradient and global average temperatures of the EECO. Our results confirm the presence of a flattened latitudinal temperature gradient and unusually high polar temperatures during the EECO, which is supported by high-latitude ecological data. We show that integrating multiple types of proxy data, and adequate prior information, has the potential to substantially reduce uncertainty in palaeoclimate reconstructions, allowing for unbiased temperature estimates from sparse data.
The purpose of this study was to investigate whether the Phyllostachys edulis-Carya illinoinensis co-plantation is a feasible forest model. Two treatments and one control were evaluated. The control was a low-density C. illinoinensis forest (CK), and the treatments were a high-density C. illinoinensis forest (DF), and a C. illinoinensis-P. edulis co-plantation forest (MF). Gas exchange and chlorophyll fluorescence parameters, leaf physiology, macromorphology, and anatomical structure of C. illinoinensis were measured and principal component analysis (PCA) was used to evaluate treatment effects. The highest net photosynthetic rate (Pn), which was 13.72 .µmol CO2·m⁻²·s⁻¹, was recorded for C. illinoinensis under the CK treatment, while the corresponding values for MF and DF treatments were 8.98 and 5.25 µmol CO2·m⁻²·s⁻¹, respectively. The JIP test revealed that plastoquinone libraries were inhibited under both MF and DF, particularly in the latter. Compared with CK, antioxidant substances in MF and DF leaves increased to a certain extent, again, particularly in the latter. Leaf macromorphology and anatomical structures under the different treatments also changed to acclimated to different environments. The leaf area of MF became lower, and the vascular tissue of DF petiole became larger. Finally, based on the main data, the order of the PCA scores was CK > MF > DF. The results indicated that both co-plantation and high-density planting caused both interspecific and intraspecific competition. Photosynthesis was inhibited in C. illinoinensis to varying degrees under both cultivation models. Nonetheless, the stress levels in C. illinoinensis were significantly lower under the co-plantation forest than under high-density planting. These findings indicate that C. illinoinensis growth was not severely inhibited by co-plantation with P. edulis, as it still developed well. Hence, co-plantation of P. edulis and C. illinoinensis is a promising mixed-forest model.
Aim
Leaves display a remarkable variety of shapes, each with potential ecological advantages in specific climates. While the relations between leaf shape and either climate or height have been relatively well studied in eudicots, the macroecological drivers of shape remain poorly known in monocots. Here, we investigated the associations between climate and plant height with the evolution of leaf shape in a clade with high species and morphological diversity.
Location
Global.
Time period
Cretaceous to contemporary.
Major taxa studied
Palms (Arecaceae).
Methods
We apply a Bayesian phylogenetic mixed model to test for associations between climate and leaf shape (all – entire‐leaved, pinnate‐dissected, palmate‐dissected and costapalmate). We further reconstruct the ancestral leaf shape using multistate speciation and extinction models and compare the frequency of shapes with global temperatures through time.
Results
We find that plant height associates with dissected leaves and that annual precipitation associates with pinnate shapes. The ancestral leaf shape is unclear, but early diversification was dominated by pinnate‐dissected palms, which has remained the most species‐rich form of leaves throughout palm history.
Main Conclusions
Palms that are tall and live in humid regions are more likely to have pinnate leaves. Through geological time scales, temperature did not play an obvious role in determining leaf shapes. This study contributes to our understanding of how the diversity of leaf shapes is linked to biological and climatic factors.
Background: How geographical isolation and ecological divergence act together to promote plant diversity in mountainous regions remains largely unknown. In this study, we chose two small genera distributed in the Sino-Himalayan region, Megacodonand Beesia, which both exhibit a fragmented distribution pattern and are found across a wide range of altitudes. By summarizing their common patterns of speciation and/or divergence processes, we aim to understand how environmental changes accelerated lineage diversification in the Sino-Himalayan region through ancient allopatry and ecological divergence.
Results: Using ddRAD-seq, chloroplast genome sequences, and specific molecular markers, we studied the phylogenetic relationships, population structure, and historical biogeography of Beesia and Megacodon. Both genera began to diverge from the late Miocene onwards, with ancient allopatry at lower altitudes formed narrow-range species or relict populations. Mantel tests between genetic distance and climatic, elevational, or geographic distance revealed an isolation-by-distance pattern in Beesia and Megacodon stylophorus. Megacodon showed two clades occupying entirely different altitudinal ranges, whereas Beesia calthifoliaexhibited a genetic divergence pattern along an altitude gradient. To investigate adaptive divergence along an altitudinal gradient, we used morphological measurements and found different elevational groups in Beesia calthifolia had distinct leaf shapes.
Conclusions: The regional disjunctions of plant groups in the Sino-Himalayan region are drastic and closely related to several biogeographic boundaries. As a consequence of major geological and climate change, ecological divergence when different altitudes are colonized often happens simultaneously within plant groups. Although the relative contributions of geographical isolation and parapatric ecological divergence are different among different plant taxa, a combined effect of these two factors is a common phenomenon in the process of heterogenization of the Sino-Himalayan region.
Leaf size varies within and between species, and previous work has linked this variation to the environment and evolutionary history separately. However, many previous studies fail to interlink both factors and are often data limited. To address this, our study developed a new workflow using machine learning to automate the extraction of leaf traits (leaf area, largest in-circle area and leaf curvature) from herbarium collections of Australian eucalypts (Eucalyptus, Angophora and Corymbia). Our dataset included 136,599 measurements, expanding existing data on this taxon’s leaf area by roughly 50-fold. With this dataset, we were able to confirm global positive relationships between leaf area and mean annual temperature and precipitation. Furthermore, we linked this trait-climate relationship to phylogeny, revealing large variation at the within-species level, potentially due to gene flow suppressing local adaptation. At deeper phylogenetic levels, the relationship strengthens and the slope converges towards the overall eucalypt slope, suggesting that the effect of gene flow relaxes just above the species level. The strengthening of trait-climate correlations just beyond the intraspecific level may represent a widespread phenomenon across various traits and taxa. Future studies may unveil these relationships with the larger sample sizes of new trait datasets generated through machine learning.
Environmental factors have a regulatory effect on plant leaf functional traits, affecting ecosystems' functions and processes. Due to special adaptive strategies, Dicranopteris dichotoma can occupy an important ecological niche at different vegetational restoration stages related to changes in leaf functional characteristics. This study was conducted to explore the changes in leaf functional traits and their responses to environmental factors in four different vegetational restoration stages in the red soil erosion area at Changting, Fujian. We measured 11 leaf functional traits and 13 environmental factors. One-way analysis of variance (ANOVA) was used to compare the differences in environment, soil factors, and leaf functional traits at different vegetation restoration stages. Redundancy analysis and partial least squares model were used to analyze the main factors affecting leaf functional traits. The results depicted that with the succession of the vegetational restoration stage, environmental factors and the functional traits of leaves exhibited significant differences (P
The aim of this study is to elucidate the spatial distribution patterns of four key plant functional traits and the effects of environmental factors on their variation in inland arid and semi-arid areas and thus provide a reference for the prediction of species distribution and biodiversity conservation in this region. The county-level distribution data sets of 3,953 seed plants species, traits data sets, and environmental variables data sets were collected in Xinjiang, China. We focused on four plant functional traits: maximum plant height, leaf size, first flowering time and flowering duration. The spatial distribution patterns of plant traits in 50 × 50 km grid cells were detected. The spatial variation in different functional traits was explored and environmental drivers were identified. The results showed that there were significant latitudinal and altitudinal gradient patterns of plant functional traits, and there were significant spatial correlations between different traits. These four traits showed a significant and strong effect of environmental interpretation. Among the three types of environmental factors (climate, soil and habitat heterogeneity), climate factors played the most pronounced role in explaining functional traits. Mean annual temperature (MAT) being the most important driver of the spatial distribution patterns of each trait, and its effect on different traits varies. Overall, vegetative and reproductive growth of plants is more favorable in areas with higher temperatures, abundant precipitation, fertile soils and high habitat heterogeneity, which is mainly reflected in higher plant height, larger leaves, earlier flowering time and longer flowering duration.
We are in a modern biodiversity crisis that will restructure community compositions and ecological functions globally. Large mammals, important contributors to ecosystem function, have been affected directly by purposeful extermination and indirectly by climate and land-use changes, yet functional turnover is rarely assessed on a global scale using metrics based on functional traits. Using ecometrics, the study of functional trait distributions and functional turnover, we examine the relationship between vegetation cover and locomotor traits for artiodactyl and carnivoran communities. We show that the ability to detect a functional relationship is strengthened when locomotor traits of both primary consumers (artiodactyls, n = 157 species) and secondary consumers (carnivorans, n = 138 species) are combined into one trophically integrated ecometric model. Overall, locomotor traits of 81% of communities accurately estimate vegetation cover, establishing the advantage of trophically integrated ecometric models over single-group models (58 to 65% correct). We develop an innovative approach within the ecometrics framework, using ecometric anomalies to evaluate mismatches in model estimates and observed values and provide more nuance for understanding relationships between functional traits and vegetation cover. We apply our integrated model to five paleontological sites to illustrate mismatches in the past and today and to demonstrate the utility of the model for paleovegetation interpretations. Observed changes in community traits and their associated vegetations across space and over time demonstrate the strong, rapid effect of environmental filtering on community traits. Ultimately, our trophically integrated ecometric model captures the cascading interactions between taxa, traits, and changing environments.
Seventeen morphological and anatomical characteristics of the leaves were selected from five natural populations to explore the variation in leaf traits of Litsea coreana var. sinensis and the effects of geographical environment on these variations. Nested analysis of variance, multiple comparisons, principal component analysis (PCA), and correlation analysis were conducted to explore the variations within and between populations and their correlation with geographical and climatic factors. Significant differences in the 17 leaf traits were observed within and among populations. On average, the relative contribution of within population variation to total variation was 24.8%, which was lower than among population variation (54.6%). The average differentiation coefficient of the traits was 65.8%, and the average coefficient of variation 11.8%, ranging from 6.7% for main vein thickness to 21.4% for petiole length. The PCA results showed that morphological characteristics were divided into two categories, and the level of variation was greater than that of leaf anatomy. Most of the leaf traits were significantly correlated with geography and climate and showed a gradual variation with longitude, latitude, and altitude. In areas with high temperatures, less rainfall, and strong seasonal rainfall, the leaves are larger, longer and thicker. This study shows that variations in leaf traits of L. coreana var. sinensis mainly come from variations among populations. The level of trait differentiation among populations is high and the level of variation within populations low. These findings help further understand leaf morphological characteristics of this species and can provide a valuable reference for the protection and sustainable utilization of this natural resource.
Važno je znati kako će klimatske promjene utjecati na pojedine šumske vrste, a pritom je jednako važno istraživati i mjeriti značajke biljaka koje je relativno lako kvantificirati, a koje su snažno povezane s cjelokupnim funkcioniranjem biljke. Iz toga je razloga provedeno istraživanje funkcionalnih značajki lišća na petogodišnjim sadnicama obične bukve (Fagus sylvatica L.) i hrasta kitnjaka (Quercus petraea /Matt./ Liebl.) porijeklom iz dviju provenijencija čija se staništa odlikuju sličnim orografskim i edafskim, a različitim klimatskim značajkama, što je posebno izraženo u količini oborine. Prema tomu, jedna je provenijencija s područja Slavonskoga Broda koja raste na staništu s manjom količinom oborine (suha provenijencija), a druga s područja Karlovca koja uspijeva na staništu s većom količinom oborine (vlažna provenijencija). Na lišću biljaka iz tih provenijencija mjerena je površina lišća (LA), gustoća puči (SD), lisna masa izražena po površini (LMA) i sadržaj suhe tvari u lišću (LDMC). Provedeno istraživanje funkcionalnih značajki lišća potvrdilo je da je hrast kitnjak u odnosu na običnu bukvu bolje prilagođen na sušne stanišne uvjete pa se može pretpostaviti da će pod utjecajem globalnih klimatskih promjena biti kompetitivniji u odnosu na običnu bukvu. Međutim, obična je bukva pokazala veću fenotipsku plastičnost koja joj može omogućiti bolju prilagodbu na buduće suše stanišne uvjete. Nadalje, utvrđeni obrazac diferencijacije sušnije i vlažnije provenijencije, uzimajući u obzir obje vrste, pokazuje njihovu ekotipsku diferencijaciju. Pri razmatranju utjecaja klimatskih promjena na prirodne populacije tih dviju vrsta treba uzeti u obzir njihovu fenotipsku plastičnost, ali i uočenu funkcionalnu ekotipsku diferencijaciju.
Understanding how the intrinsic ability of populations and species to meet shifting selective demands shapes evolutionary patterns over both short and long timescales is a major question in biology. One major axis of evolutionary flexibility can be measured by phenotypic integration and modularity. The strength, scale, and structure of integration may constrain or catalyze evolution in the face of new selective pressures. We analyze a dataset of seven leaf measurements across Vitaceae to examine whether the structure of macroevolutionary integration is linked to transitions between temperate and tropical habitats by examining how the structure of integration shifts at discrete points along a phylogeny. We also examine these patterns in light of lineage diversification rates to understand how and whether patterns in the evolvability of complex multivariate phenotypes are linked to higher-level macroevolutionary dynamics. We found that shifts in the structure of macroevolutionary integration in leaves coincide with early colonization events into new climates and that lineages that are more climatically labile are more weakly integrated overall. These more evolutionarily flexible lineages also had higher lineage turnover, suggesting a link between shifting vectors of selection, internal constraint, and lineage persistence in the face of changing environments.
The third edition of Gordon Bonan's comprehensive textbook introduces an interdisciplinary framework to understand the interaction between terrestrial ecosystems and climate change. Ideal for advanced undergraduate and graduate students studying ecology, environmental science, atmospheric science, and geography, it reviews basic meteorological, hydrological, and ecological concepts to examine the physical, chemical, and biological processes by which terrestrial ecosystems affect and are affected by climate. This new edition has been thoroughly updated with new science and references. The scope has been expanded beyond its initial focus on energy, water, and carbon to include reactive gases and aerosols in the atmosphere. The new edition emphasizes the Earth as a system, recognizing interconnections among the planet's physical, chemical, biological, and socioeconomic components, and emphasizing global environmental sustainability. Each chapter contains chapter summaries and review questions, and with over 400 illustrations, including many in color, this textbook will once again be an essential student guide.
Aim
Analysis of the shifts in the climatic space for invasive species between native and introduced areas is a powerful tool for understanding their distribution patterns and the factors influencing their spread into new areas. In this study, we explored the shift in climatic distribution between ranges for invasive woody legumes and how the functional traits of these species are associated with their climatic distribution.
Location
Global.
Time period
Present.
Major taxa studied
Invasive woody legumes.
Methods
We evaluated the global patterns of occupation of the climatic space for 107 invasive woody legumes in their native and introduced distribution ranges, in addition to the differences in six key functional traits. We used the trait probability density (TPD) function to estimate species probabilistic niches. We then classified species into four groups according to the climatic differences between the distribution ranges. The comparisons between the climate shift groups and the distribution ranges were evaluated with mixed linear models. Additionally, we compared the functional traits between species groups using ANOVA.
Results
Overall, we found that invasive species exhibited low to moderate climatic overlap between their native and introduced distribution ranges. However, climatic conditions in the introduced range were different from those in the native range. Invasive legumes were clustered in four groups (conserved, expansion, dissociation and unfilling), with dissociation between climate niches being the most common one. In terms of functional traits, the most relevant finding was that the species in the expansion group had larger leaves than species in the dissociation group.
Main conclusions
Our results showed no consistent climatic range shift across all invasive woody legume species from their native to their introduced distribution. However, some species tended to invade climatic conditions that were different from those in their native range, supporting the hypothesis that some invasive species are able to adapt to novel environmental conditions. Finally, functional traits might be a good predictor of how these species modify their climatic spaces.
A new assemblage of fossil leaves and wood is described from the uppermost Aguja Formation (upper Campanian) of Big Bend National Park, Texas, USA. While diverse leaf assemblages have been reported from Campanian through Maastrichtian strata in more northerly areas of North America, few have been so far described from southern localities. The leaf assemblage was found preserved within a lenticular tuff bed. The number of species (7) of leaves in the assemblage is low and includes one fern and six dicots. Most specimens represent taxa which have small leaves with entire margins, a morphology consistent with a dry, warm climate. Thin sections of several fossil wood samples found nearby at the same stratigraphic interval as the tuff reveals that the fossil woods represent conifers with irregularly-spaced growth rings. The assemblage may represent shrubby vegetation within an open, conifer-dominated woodland which developed within a periodically dry environment. However, the assemblage may also represent early successional species that grew in areas that had been previously disturbed by deposition of pyroclastic material. A comparison of two localities in the uppermost Aguja Formation reveal the occurrence of two types of vegetational communities – one exemplified by presumably riparian, evergreen angiosperm woodlands and another exemplified by interfluvial conifer forest with an associated herbaceous community. Given that both sites preserve very similar depositional facies, it seems that observed differences involving fossil wood taxonomy and structure are likely related to the local availability of water.
This paper investigates leaf morphology variation of the strawberry tree (Arbutus unedo) within and between two natural contrasting populations of significant latitudinal difference (Kassandreia, Chalkidiki and Ancient Olympia, Peloponnese). This study employed 11 leaf size and shape parameters, recorded by image processing and analyzing software. The results showed that in the measurements of central tendency (parameter means) the northern population of Kassandreia presented the highest values, while in contrast the highest values in the measurements of spread were found in the southern population of Ancient Olympia. Moreover, statistically significant differences between populations were detected in leaf size, but not in leaf shape parameters. Results are discussed in the context of their value in studying quantitative population differentiation and laying the basis of more advanced studies.
Pollinator selection on floral traits is a well-studied phenomenon, but less is known about the influence of climate on this species interaction. Floral trait evolution could be a result of both adaptation to climate and pollinator-mediated selection. In addition, climate may also determine pollinator communities, leading to an indirect influence of climate on floral traits. In this study, we present evidence of both direct and indirect effects of climate on plant morphology through a phylogenetic comparative analysis of the relationships between climate, pollinators, and morphology in 89 European and Mediterranean Silene species. Climate directly influences vegetative morphology, where both leaf size and internode length were found to be smaller in habitats that are warmer in the driest quarter of the year and that have more precipitation in the coldest quarter of the year. Similarly, flower size was directly influenced by climate, where smaller calyxes were also associated with habitats that are warmer in the driest quarter of the year. These results suggest that reduced leaf and flower size promote water conservation in species that occupy arid climates. Floral traits also evolved in response to pollinators, with elongated calyxes associated with nocturnal pollination, though we also found evidence that climate influences pollinator distribution. Nocturnal pollinators of Silene are found in habitats that have more temperature evenness across seasons than diurnal pollinators. Correspondingly, nocturnally-pollinated Silene are more likely to occur in habitats that have lower daily temperature fluctuation and more temperature evenness across seasons. Altogether these results show that climate can directly influence vegetative and floral morphology, but it can also affect pollinator distribution, which in turn drives floral adaptation. Our study therefore suggests that climate mediates the influence of species interactions on trait evolution by imposing direct selective demands on floral phenotypes and by determining the pollinator community that imposes its own selective demands on flowers.
The origins of South America’s exceptional plant diversity are poorly known from the fossil record. We report on unbiased quantitative collections of fossil floras from Laguna del Hunco (LH) and Río Pichileufú (RP) in Patagonia, Argentina. These sites represent a frost‐free humid biome in South American middle latitudes of the globally warm Eocene. At LH, from 4,303 identified specimens, we recognize 186 species of plant organs and 152 species of leaves. Adjusted for sample size, the LH flora is more diverse than comparable Eocene floras known from other continents. The RP flora shares several taxa with LH and appears to be as rich, although sampling is preliminary. The two floras were previously considered coeval. However, 40Ar/39Ar dating of three ash‐fall tuff beds in close stratigraphic association with the RP flora indicates an age of \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $47.46\pm 0.05$ \end{document} Ma, 4.5 million years younger than LH, for which one tuff is reanalyzed here as \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $51.91\pm 0.22$ \end{document} Ma. Thus, diverse floral associations in Patagonia evolved by the Eocene, possibly in response to global warming, and were persistent and areally extensive. This suggests extraordinary richness at low latitudes via the latitudinal diversity gradient, corroborated by published palynological data from the Eocene of Colombia.
The isotopic composition of paleosol carbonate and organic matter were investigated in the Bighorn Basin, Wyoming, to explore changes in the carbon cycle and climate across the Paleocene-Eocene boundary. In three different measured sections, soil carbonate δ13C values change in phase with marine surface water carbonates on both long (∼7 m.y.) and short (∼100 k.y.) time scales. The carbon cycle perturbations at the Paleocene-Eocene Boundary Thermal Maximum (PETM) and the Eocene Warm Interval (EWI) are recorded in multiple sections, providing unambiguous links between marine and continental deposits. The PETM and EWI δ13C excursions in the Bighorn Basin are larger than those in the surface ocean, but the reasons for this amplification are unclear. Organic matter samples from the Bighorn Basin yield noisy δ13C records that do not mirror global changes, perhaps due to diagenetic alteration or postformational contamination. The δ18O values of soil carbonate are subject to multiple climatic influences that are often antagonistic. Although the δ18O shifts at the PETM and EWI are small, the shift at the PETM is statistically significant in two of the measured sections. Assuming a plausible range of values for the meteoric water δ18O/mean annual temperature relationship, the perturbation in soil carbonate δ18O at the PETM is consistent with an increase in meteoric water δ18O of ∼2% and changes in local temperature of 3-7 °C.
A revised and updated classification for the families of flowering plants is provided. Many recent studies have yielded increasingly detailed evidence for the positions of formerly unplaced families, resulting in a number of newly adopted orders, including Amborellales, Berberidopsidales, Bruniales, Buxales, Chloranthales, Escalloniales, Huerteales, Nymphaeales, Paracryphiales, Petrosaviales, Picramniales, Trochodendrales, Vitales and Zygophyllales. A number of previously unplaced genera and families are included here in orders, greatly reducing the number of unplaced taxa; these include Hydatellaceae (Nymphaeales), Haptanthaceae (Buxales), Peridiscaceae (Saxifragales), Huaceae (Oxalidales), Centroplacaceae and Rafflesiaceae (both Malpighiales), Aphloiaceae, Geissolomataceae and Strasburgeriaceae (all Crossosomatales), Picramniaceae (Picramniales), Dipentodontaceae and Gerrardinaceae (both Huerteales), Cytinaceae (Malvales), Balanophoraceae (Santalales), Mitrastemonaceae (Ericales) and Boraginaceae (now at least known to be a member of lamiid clade). Newly segregated families for genera previously understood to be in other APG-recognized families include Petermanniaceae (Liliales), Calophyllaceae (Malpighiales), Capparaceae and Cleomaceae (both Brassicales), Schoepfiaceae (Santalales), Anacampserotaceae, Limeaceae, Lophiocarpaceae, Montiaceae and Talinaceae (all Caryophyllales) and Linderniaceae and Thomandersiaceae (both Lamiales). Use of bracketed families is abandoned because of its unpopularity, and in most cases the broader circumscriptions are retained; these include Amaryllidaceae, Asparagaceace and Xanthorrheaceae (all Asparagales), Passifloraceae (Malpighiales), Primulaceae (Ericales) and several other smaller families. Separate papers in this same volume deal with a new linear order for APG, subfamilial names that can be used for more accurate communication in Amaryllidaceae s.l., Asparagaceace s.l. and Xanthorrheaceae s.l. (all Asparagales) and a formal supraordinal classification for the flowering plants.
Leaf size variation with respect to climate was studied at 35 sample sites reported in the literature from the Western Hemisphere. The variation in leaf size was analyzed by plotting the sample sites on Holdridge's (1967) life zone chart and comparing the percentage of species having large leaves (greater than 20.25 sq cm in area) in the different life zones. Four foliar belts were identified in the tropical basal and altitudinal belts. Three of these foliar belts were identified earlier in a field study carried out in Costa Rica (Dolph and Dilcher in press). The fourth foliar belt is not found in Costa Rica because it is confined to very dry basal belt life zones. It was concluded that leaf size cannot be used to identify specific life zones or climates in either extant or fossil floras.
Global climate during the Mesozoic and early Cenozoic is thought to have been warmer than at present, but there is debate about winter temperatures. Paleontological data indicate mild temperatures even at high latitudes and in mid-latitude continental interiors, whereas computer simulations of continental paleoclimates produce winter temperatures closer to modern levels. Foliar physiognomy and floristic composition of 23 Eocene floras from the interior of North America and Australia indicate cold month means generally >2°C, even where the mean annual temperature (MAT) was <15°C. Reconstructed Eocene latitudinal gradients of MAT are curvilinear but are about 0.4°C per 1° of latitude in continental interiors of mid-latitudes, much less than the 0.8-1.0°C per 1° of latitude observed in eastern and central North America today, but similar to modern gradients in the Southern Hemisphere mid-latitudes and on the west coast of North America. -from Authors
Estimates of past precipitation are of broad interest for many areas of inquiry, including reconstructions of past environments and topography, climate modeling, and ocean circulation studies. The shapes and sizes of living leaves are highly sensitive to moisture conditions, and assemblages of fossil leaves of flowering plants have great potential as paleoprecipitation indicators. Most quantitative estimates of paleoprecipitation have been based on a multivariate data set of morphological leaf characters measured from samples of living vegetation tied to climate stations. However, when tested on extant forests, this method has consistently overestimated precipitation. We present a simpler approach that uses only the mean leaf area of a vegetation sample as a predictor variable but incorporates a broad range of annual precipitation and geographic coverage into the predictor set. The significant relationship that results, in addition to having value for paleoclimatic reconstruction, refines understanding of the long-observed positive relationship between leaf area and precipitation. Seven precipitation estimates for the Eocene of the Western United States are revised as lower than previously published but remain far wetter than the same areas today. Abundant moisture may have been an important factor in maintaining warm, frost-free conditions in the Eocene because of the major role of water vapor in retaining and transporting atmospheric heat.
Leaf teeth are conspicuous and often diagnostic features of many plant species. In mesic environments with sufficient nutrient resources, the percentage of toothed species in extant floras generally correlates negatively with temperature; consequently, fossil leaf teeth are widely used to estimate continental paleotemperatures. However, the function of leaf teeth with respect to climate is poorly understood. Here, we test the hypothesis that teeth enhance rates of carbon uptake at the beginning of the growing season when temperatures are limiting. We measure the seasonal patterns of leaf-margin photosynthesis and transpiration for 60 woody species from two temperate regions with differing climates (Pennsylvania and North Carolina). Three sig- nificant results are, first, physiological activity at leaf margins is greatest early in the growing season (first 30 d); second, toothed margins are more active with respect to photosynthesis and transpiration than untoothed mar- gins; finally, leaf margins are more active in species native to colder Pennsylvania. The toothed species increase transpiration and photosynthate production early in the growing season relative to untoothed species and do so more in the Pennsylvania sample, maximizing carbon gain when temperature is limiting but moisture and nutrient availability are not. This mechanism may provide a proportionally increasing selective advantage to toothed species with decreasing temperature that is reflected in empirical correlations used for paleo- temperature estimation.
Leaf margin analysis (LMA), which is based on a correlation between the proportion of woody dicot species with nontoothed leaf margins and mean annual temperature, has been promoted as a tool for estimating mean annual temperature (MAT) from fossil-leaf assemblages. The original LMA calibration was based on East Asian mesic vegetation, and substantially the same relationship has been shown for other geographical regions, including Australian mesic vegetation. In this report, taphonomic effects are assessed using autochthonous samples from extant Australian forests for sites ranging from tropical lowland rainforest and monsoonal deciduous woodland to temperate rainforest with and without emergent Eucalyptus, and for parautochthonous and allochthonous (i.e., streambed) leaf accumulations. MAT was estimated within the binomial sampling error of the estimate for 27 of 30 (90%) of the test sites, and was found to underestimate MAT systematically when applied to streambed leaf assemblages. This result may reflect the stream side bias detected in recent studies of tropical forests in South America. Sites where MAT was overestimated are of low species richness (<10 spp.).
Paleoecological studies enhance our understanding of biotic response to climate change because they consider timescales not accessible through laboratory or ecological studies. From 60 to 51 million years ago (Ma), global temperatures gradually warmed to the greatest sustained highs of the last 65 million years. Superimposed on this gradual warming is a transient spike of high temperature and pCO 2 (partial pressure of carbon dioxide in the atmosphere; the Paleocene-Eocene Thermal Maximum 55.8 Ma) and a subsequent short-term cooling event (∼54 Ma). The highly resolved continental fossil record of the Bighorn Basin, Wyoming, USA, spans this interval and is therefore uniquely suited to examine the long-term effects of temperature change on the two dominant groups in terrestrial ecosystems, plants and insect herbivores. We sampled insect damage on fossil angiosperm leaves at nine well-dated localities that range in age from 52.7 to 59 Ma. A total of 9071 leaves belonging to 107 species were examined for the presence or absence of 71 insect-feeding damage types. Damage richness, frequency, and composition were analyzed on the bulk floras and individual host species. Overall, there was a strong positive correlation between changes in damage richness and changes in estimated temperature, a weak positive relationship for damage frequency and temperature, and no significant correlation for floral diversity. Thus, insect damage richness appears to be more sensitive to past climate change than to plant diversity, although plant diversity in our samples only ranges from 6 to 25 dicot species. The close tracking of the richness of herbivore damage, a presumed proxy for actual insect herbivore richness, to both warming and cooling over a finely divided, extended time interval has profound importance for interpreting the evolution of insects and plant–insect associations in the context of deep time. Our results also indicate that increased insect herbivory is likely to be a net long-term effect of anthropogenic warming.
The Eocene was the warmest part of the Cenozoic, when warm climates extended into the Arctic, and substantive paleobotanical evidence indicates broadleaf and coniferous polar forests. Paleontological temperature proxies provide a basis for understanding Arctic early Paleogene climates; however, there is a lack of corresponding proxy data on precipitation. Both leaf physiognomic analysis and quantitative analysis of nearest living relatives of an Arctic macroflora indicate upper microthermal to lower mesothermal moist climates (mean annual temperature ∼13–15 °C; cold month mean temperature ∼4 °C; mean annual precipitation >120 cm/yr) for Axel Heiberg Island in the middle Eocene. Leaf-size analysis of Paleocene and Eocene Arctic floras demonstrates high precipitation for the Paleogene western and eastern Arctic. The predicted enormous volume of freshwater entering the Arctic Ocean as a result of northward drainage of a significant region of the Northern Hemisphere under a high-precipitation regime would have strongly affected Arctic Ocean salinity, potentially supporting Arctic Ocean Azolla blooms. High Paleogene precipitation around the Arctic Basin is consistent with high atmospheric humidity, which would have contributed significantly to polar, and global, Eocene warming.
Few South American macrofloras of Paleocene age are known, and this
limits our knowledge of diversity and composition between the
end-Cretaceous event and the Eocene appearance of high floral diversity.
We report new, unbiased collections of 2516 compression specimens from
the Paleocene Salamanca Formation (ca. 61.7 Ma) from two localities in
the Palacio de los Loros exposures in southern Chubut, Patagonia,
Argentina. Our samples reveal considerably greater richness than was
previously known from the Paleocene of Patagonia, including 36 species
of angiosperm leaves as well as angiosperm fruits, flowers, and seeds;
ferns; and conifer leaves, cones, and seeds. The floras, which are from
siltstone and sandstone channel-fills deposited on low-relief floodplain
landscapes in a humid, warm temperate climate, are climatically and
paleoenvironmentally comparable to many quantitatively collected
Paleocene floras from the Western Interior of North America. Adjusted
for sample size, there are >50% more species at each Palacio de los
Loros quarry than in any comparable U.S. Paleocene sample. These results
indicate more vibrant terrestrial ecosystems in Patagonian than in North
American floodplain environments ˜4 m.y. after the end-Cretaceous
extinction, and they push back the time line 10 m.y. for the evolution
of high floral diversity in South America. The cause of the dis parity
is unknown but could involve reduced impact effects because of greater
distance from the Chicxulub site, higher latest Cretaceous diversity, or
faster recovery or immigration rates.
Corylopsis reedae Radtke, Pigg et Wehr sp. nov. and Fothergilla malloryi Radtke, Pigg et Wehr sp. nov. (Hamamelidaceae) are described from the lower Eocene (49-50 million years ago) Republic flora of northeastern Washington State. Corylopsis reedae is the first unequivocal fossil leaf report of Corylopsis Siebold & Zucc. (cv. Winter Hazel). The species is based on a single specimen that is 1.9 cm wide, preserved for 3.4 cm in length and estimated to be ca. 4 cm long, with an asymmetrical base and teeth that are concave apical, straight basal, with simple apices. The fossil leaf is remarkably similar to extant Corylopsis, with prominent compound agrophic veins; strong, straight secondaries; and closely spaced, ladder-rung-like, opposite to alternate percurrent tertiaries at right angles to the secondaries. Today this genus occurs only in Asia, but the fossil record, primarily of seeds, indicates it was widely distributed in North America and Europe during the Tertiary. Fothergilla malloryi documents conclusively the presence of this genus in the lower Eocene of North America for the first time. This leaf is 4.4 cm long x 3.5 cm wide and slightly lobate, with low, widely spaced teeth on the margin, an asymmetric apex, and a cordate base. This occurrence represents the oldest record for the genus, which is also known in the Oligocene of North America and several Neogene Asian localities. Today, Fothergilla (cv. Witch Alder) is native to southeastern North America. The occurrence at Republic of these two hamamelid plants underscores the diversity of the northwestern "Okanogan Highlands" flora of British Columbia, Canada, and Washington State, and demonstrates the Early Eocene presence of two disjunct hamamelid genera. These occurrences provide new data for better understanding the evolution and biogeography of the family.
There are several methods of predicting terrestrial palaeoclimates from the
size and shape of fossil leaves (foliar physiognomy). The assumptions and
sources of uncertainty of these methods are considered and used to determine
the true uncertainty. Their ability to predict mean annual temperature (MAT)
is poor. The approximate standard errors for samples of living vegetation in
North America are in the range of 1.7˚C to 2.5˚C, but the true
uncertainty for fossil samples is higher. Specimens with very different
physiognomy to typical specimens in the model have higher uncertainties.
Besides these uncertainties, the processes of fossilisation, the allocation of
specimens to taxa, and the effects of other factors on foliar physiognomy all
increase the uncertainty of the predictions. Overall uncertainties in the
predictions of MAT are equivalent to standard errors of about 3–5˚C
depending on the nature of the fossil site and flora. Other factors affect
foliar physiognomic predictions significantly because predicted MAT does not
change as rapidly with altitude as true MAT, and floras from different parts
of the world with similar temperatures give different temperature predictions.
Mean annual temperature and one precipitation parameter (probably mean annual
precipitation or the growing season precipitation) can be predicted more or
less independently, although the predictions of precipitation are weak.
Physiognomic signals for other climatic parameters are weak or apparently
non-existent, and previously published predictions of past equability are
primarily based on correlations with modern MAT, rather than physiognomy.
In the last decade, several statistical models have been proposed to quantify the relationships among leaf morphological characters and climate parameters. The models, based on modern plants and climate from varying geographic areas, and derived using varied statistical analyses, were intended for paleoclimatic reconstruction based on the morphological characters of fossil leaves. The goal of the research presented here is to evaluate these and newly constructed models in order to estimate past climate in tropical Africa from fossil leaves. Models found to estimate current climate most accurately using modern African leaf assemblages are used to estimate past climate from fossil leaves at three middle and late Miocene paleobotanical sites in the Tugen Hills, Kenya.
Regression models derived from predictor data having a majority of sites from higher than 25°N-S latitude consistently overestimate mean annual precipitation at modern African sites by an average of 990 mm. A pronounced cold season, as at high latitudes, has an inhibitory effect on leaf size, the primary correlate of rainfall, and may negatively affect the accuracy with which models derived from high latitudes estimate rainfall in the Tropics, which lack a cold season. Models derived from data sets consisting of samples from 25°N-S latitude yield similar and more accurate estimates for mean annual precipitation at modern African sites, expressing the predominant relationship between yearly or seasonal rainfall and leaf size at lower latitudes. Models that estimate temperature parameters, whether derived from high or low latitudes, were found to be inaccurate with modern tropical African samples. The hypothesis is proposed that non-entire margins, the primary correlate with temperature, are more likely to be present on the leaves of deciduous plants, whether they lose their leaves because of cold (at high latitudes) or seasonal drought (at low latitudes). Generally, this study indicates that modern predictor data sets from which models are drawn should be representative of the predominant climate parameters expected among fossil sites.
Four regression models are approximately equal in their ability to estimate accurately mean annual precipitation at the modern African sites. They are derived from African data or combinations of African plus other low-latitude data and provide consistent rainfall reconstructions at the three fossil sites. Estimates are 955 ± 29 to 1185 ± 96 mm/yr for Kabarsero (12.6 Ma), 490 ± 46 to 693 ± 32 mm/yr for Waril (9–10 Ma), and 730 ± 30 to 1019 ± 32 mm/yr for Kapturo. Wet-months precipitation estimates are 857 ± 30 mm/yr for Kabarsero, 437 ± 30 for Waril, and 627 ± 30 for Kapturo.
These are the first quantitative estimates of climate for the Miocene of East Africa. The seasonally dry climate inferred for Waril may indicate that the Asian monsoon was established by about 9–10 Ma. Alternatively, the seasonally dry climate may reflect local topographic changes caused by rift valley development. However, the plant localities suggest that, although progressive drying may have been a trend during the Tertiary, there was not a unidirectional change from forested to open environments in the Kenya rift between 12.6 and 6.8 Ma, the time interval just prior to the origin of hominids.
The principle of optimal design (Rosen 1967) can be stated as follows. `Natural selection leads to organisms having a combination of form and function optimal for growth and reproduction in the environments in which they live.' This principle provides a general framework for the study of adaptation in plants and animals. The efficiency of water use by plants (Slatyer 1964) can be defined as grams of carbon dioxide assimilated per gram of water lost. Leaf temperatures, transpiration rates, and water-use efficiencies can be calculated for single leaves using well-established principles of heat and mass transfer. The calculations are complex, however, depending on seven independent variables such as air temperature, humidity and stomatal resistance. The calculations can be treated as artificial data in a 2N factorial design experiment. This technique is used to compare the sensitivity of the system response variables to changes in the independent variables, and to their interactions. The assumption is made (as a first approximation) that the optimal leaf size in a given environment is the size yielding the maximum water-use efficiency. This very simple assumption leads to predictions of trends in leaf size which agree well with the observed trends in diverse regions (tropical rainforest, desert, arctic, etc.). Specifically, the model predicts that large leaves should be selected for only in warm or hot environments with low radiation (e.g. forest floors in temperate and tropical regions). There are some plant forms and microhabitats for which observed leaf sizes disagree with the predictions of the simple model. Refinements are thus proposed to include more factors in the model, such as the temperature dependence of net photosynthesis. It is shown that these refinements explain much of the lack of agreement of the simpler model. One of the main roles of mathematical models in science is `to pose sharp questions' (Kac 1969). The present model suggests several speculative propositions, some of which would be difficult to prove experimentally. Others, whether true or not, can serve as a theoretical framework against which to compare experimental results. The propositions are as follows. (1) Every environment tends to select for leaf sizes increasing the efficiency of water utilization, that is, the ratio of CO2 uptake to water loss. (2) Herbs are physiologically different from woody plants, in such a way that water-use efficiency has been more important in the evolution of the latter. (3) The stomatal resistance of a given leaf varies diurnally in such a way that the water-use efficiency of that leaf tends to be a maximum. (4) The larger the photosynthesizing surface of a desert succulent, the more likely it is to exhibit acid metabolism, with stomata open at night and closed during the day. (5) In arctic and alpine regions, the plant species whose carbohydrate metabolism is most severely limited by low temperatures are most likely to evolve a cushion form of growth. In addition to providing these testable hypotheses, the results of the model may be useful in other ways. For example, they should help plant breeders to alter water-use efficiencies, and they could help palaeobotanists interpret past climates from fossil floras.
The objective of this book is to make analytical methods available to students of ecology. The text deals with concepts of energy exchange, gas exchange, and chemical kinetics involving the interactions of plants and animals with their environments. The first four chapters are designed to show the applications of biophysical ecology in a preliminary, sim plified manner. Chapters 5-10, treating the topics of radiation, convec tion, conduction, and evaporation, are concerned with the physical environment. The spectral properties of radiation and matter are thoroughly described, as well as the geometrical, instantaneous, daily, and annual amounts of both shortwave and longwave radiation. Later chapters give the more elaborate analytical methods necessary for the study of photosynthesis in plants and energy budgets in animals. The final chapter describes the temperature responses of plants and animals. The discipline of biophysical ecology is rapidly growing, and some important topics and references are not included due to limitations of space, cost, and time. The methodology of some aspects of ecology is illustrated by the subject matter of this book. It is hoped that future students of the subject will carry it far beyond its present status. Ideas for advancing the subject matter of biophysical ecology exceed individual capacities for effort, and even today, many investigators in ecology are studying subjects for which they are inadequately prepared. The potential of modern science, in the minds and hands of skilled investigators, to of the interactions of organisms with their advance our understanding environment is enormous.
although it is clear that leaves are central to a plant’s adaptation for growth and competitive survival, the actual nature of the contribution of leaf form to plant adaptation is complex. For example, the size and shape of leaves can affect the rates at which leaves exchange heat, take up carbon dioxide, and lose water vapor. Leaf size and shape can also affect the efficiency with which the total photosynthetic surface can be arranged, supported, and supplied. Adaptations in leaf form thus touch on several aspects of plant form and function, with implications for thermoregulation (Gates et al., 1968), efficiency of water use (Parkhurst and Loucks, 1972), photosynthetic potential (Cunningham and Strain, 1969), branching and rooting strategies (Givnish and Vermeij, 1976), productivity (Tsunoda, 1972), and, presumably, competitive ability.
The Climate Leaf Analysis Multivariate Program (CLAMP) is an established methodology for physiognomic analysis of dicot leaf floras. This paper uses a meta-analysis of four studies that provide CLAMP data on 245 floras from Asia, Africa, and North and South America to demonstrate the application of a new analytical methodology for the exploration of the relationship between leaf morphology and environment. This methodology involves the application of a generalized "pairs" plot or scatter plot matrix (SPLOM), a form of graphical analysis for multivariate data. It is compared with the results from regression, hierarchical cluster analysis, principle components analysis, and canonical correspondence analysis. Analysis of the available data using pairs plots reveals extensive multiple covariation among explanatory leaf physiognomic variables and identifies sources of systematic error that eigenvector ordination methods tend to conceal. Pairs plots provide a supplementary method for analyzing complex multivariate data on leaf physiognomy and contribute to biological understanding of leaf-environment interactiohs. Because pairs plots allow more flexible investigation of multivariate data than existing eigenvector and regression-based approaches, they may prove useful not only for analyzing CLAMP data but also in exploring multiple covariation in other complex paleontological data sets.
Section 1 reviews 23 ecological patterns in leaf form, physiology and arrangement. Three general sets of energetic trade-offs, involving the economics of gas exchange, support and biotic interactions, appear likely to influence the evolution of leaves and underlie these trends. The first of these trade-offs is illustrated with an analysis of the adaptive significance of leaf size, in both terrestrial and aquatic plants. Section 2 addresses the role of selective pressures and phylogenetic constraints in determining features of leaf form and phenology in forest herbs. Ecological comparisons of 74 species from a site in the Virginia Piedmont show that members of each temporal photosynthetic guild display evolutionary convergence in several aspects of leaf form and arrangement. These convergences can each be understood in terms of models that assume that selection favours plants whose form and physiology tend to maximize whole-plant growth. Congeners of guild members share the same leaf phenology as the guild members themselves. This suggests that phenology is evolutionarily rather non-labile within genera but that, within guilds, species in several different genera and families converge strongly in other leaf traits. Section 3 reviews an analysis of adaptive radiation in leaf shape among violets of E North America. Each ecological group of species displays the leaf shape expected on functional grounds and separate lineages show parallel trends.-from Author
The physiognomic-structural features used to classify Australian rain forest vegetation into 20 structural types vary along different gradients. The high correlation demonstrated between the structural types and the climatic and edaphic factors enables the identificatin of habitat types which are defined by limits of mean annual temperature and rainfall, and soil mineral status and soil drainage. The physiognomic-structural features are arranged in a hierarchical table. The primary division into vine, fern, and moss forests corresponds with tropical-subtropical, warm temperate (submontane), and cool temperate (montane) thermal regions, respectively. The temperate forms are strictly evergreen. Further subdivision of the vine forests into evergreen (including associated sclerophyll forests) and raingreen (more of less deciduous) types is correlated with differences in soil mineral status as inferred from topography, depth of soil, and parent materials. The tropical forms are differentiated from the sub-tropical forms by a higher proportion of mesophyll than notophyll leaf sizes. Further differentiation of vine forests with complex, mixed, and simple structure is correlated with inferred soil nutrient status defined as eutrophic, mesotrophic, and enriched obligotrophic. Obligotrophic soils do not support rain forest vegetation. Climatic and topographic factors tend to outweigh soil nutrient availibility at the climate extremes of the monsoonal and cool temperate regions. The structure types are finally differentiated by differences in height of canopy closure, nature of emergents, or proportion of deciduous species, and are further correlated with variations in soil moisture availability and drainage, or local exposure in montane situations. A field key to the habitat types associated with the different structural types is given. The inter-relationships thus established enable the prediction of either the type of vegetation, climate, or soil once any two of these are known. Deviations from the inferred distribution of rain forest are related to the past influence of wildfires which favor the regeneration of eucalypts and other scle sclerophylls after the destruction of the mostly fire-sensitive rain forest species. Destruction by surface fires in the tropical-subtropical region, or by running-crown fires of the mass-ignition type in the temperate regiion results respectively in abrupt ecotones, or diffuse ecotones and the virtual absence of climax rain forest vegetation. The practical implications of the ecological relationships established are briefly discussed in relation to land use and conservation.