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Evaluating the role of phenology in managing urban invasions: A case study of Broussonetia papyrifera
Abstract
Multidisciplinary approaches are required for the management of invasive woody species in urban areas. In this context, phenological studies are a useful tool to understand tree development and devise suitable management strategies under urban forestry conditions. The significant role of phenology in attributing competitive advantages to invasive alien species has also been long recognized by community ecologists. Therefore, phenological calendars of invasive species may help in their detection, management and mitigation. In the present study, an attempt has been made to understand the invasive potential of an emerging invasive tree of urban landscapes, Broussonetia papyrifera (paper mulberry; Moraceae), through its phenological assessment by using a standardized numerical scale, BBCH (Biologische Bundesanstalt, Bundessortenamt, CHemische Industrie). The tree is native to southeastern and eastern Asia and the Pacific Islands, and is rapidly spreading across various tropical and subtropical regions. The phenology of B. papyrifera was described in eight principal growth stages (PGSs) with two developmental cycles in a year, presented as primary (January-June) and secondary (June-November) flushes. The observations were further supported by the corresponding dates, photographs, meteorological data (air temperature, precipitation, and photoperiod), and climatic water balance of the study area. Results suggest that the occurrence of two developmental cycles, a prolonged reproductive period, strategy to attract frugivores with brightly colored pulpy fruits, and ability to survive under a wide temperature range help in the spread of B. papyrifera. The phenological scale provided in this study describes accurate and precise developmental stages of the tree that can be used to devise efficient management strategies for its control in urban areas. The information can also be exploited for assessing the climatic conditions required for its prevalence, predicting its future geographic range, and further research.
... We therefore sought to determine how the diversity, composition and structure of native liana and tree communities and liana-tree interaction networks responded to invasion by three tree species (Broussonetia papyrif-era¸ Cedrela odorata, Tectona grandis) in two moist semi-deciduous forests in Ghana. Effects of plant invasion on native liana and tree community structure and liana-tree network structure were quantified by sampling liana species with diameter at 1.30 m from species outcompete native species and inflict negative impacts on their diversity, composition, abundance and regeneration (Hejda et al. 2009;Vilà et al. 2011;Sun and Junod 2017;Ruwanza 2019;Langmaier and Lapin 2020;El-Barougy et al. 2021), though the use of strategies relating to their phenological and allelopathic features, and their ability to alter habitats (Ikhajiagbe et al. 2020;Maan et al. 2020;Pasiecznik 2022). Consequently, invasive plants can integrate into liana and tree communities, and modify their assemblages and interactions. ...
... B. papyrifera uses early and extended leaf and fruit phenology over a wide range of temperatures as a strategy for spreading (Maan et al. 2020). C. odorata also uses prolific seed production and wind dispersal mode to spread rapidly and invade disturbed sites (Pasiecznik 2022). ...
... Perhaps, B. papyrifera possesses features that tend to make them better hosts compared to the other invasive tree species. Furthermore, the phenological advantage of the species which accounts for its spread (Maan et al. 2020) might have contributed to its ability to connect to many liana species (i.e., high connectance) and alter network properties. Previous studies on plant-pollinator networks reported that invasive plant species tend to attract more pollinators at the expense of native plant species, resulting in increased number of interactions with pollinator species, making the invasive plant species module hubs (Albrecht et al. 2014;Parra-Tabla and Arceo-Gómez 2021). ...
Invasive plants are one of the greatest threats leading to biodiversity loss and species extinction worldwide. Understanding the responses of liana and tree communities as well as liana-tree interactions to plant invasion could be important in biodiversity conservation and ecosystem functioning, but there is limited knowledge on this subject matter. We therefore sought to determine how the diversity, composition and structure of native liana and tree communities and liana-tree interaction networks responded to invasion by three tree species (Broussonetia papyrifera¸ Cedrela odorata, Tectona grandis) in two moist semi-deciduous forests in Ghana. Effects of plant invasion on native liana and tree community structure and liana-tree network structure were quantified by sampling liana species with diameter at 1.30 m from rooting base ≥ 1 cm, and tree species with diameter at breast height ≥ 5 cm in 20 20 × 20 m plots each in non-invaded and invaded sites. The findings of the study showed that plant invasion was associated with lower diversity and abundance of lianas and trees as well as shifts in species composition of the plants. Our results revealed that plant invasion influenced the patterns of liana-tree network structure, and tended to cause an increase in network connectance and nestedness, and a decrease in network modularity and specialisation. Plant invasion drove the topological roles of a few liana and tree species in the invaded sites. Generally, species abundance and specificity were important correlates of nestedness, and modularity and species roles of the networks. We conclude that the invasive tree species drove native liana and tree community structure, degree of liana-tree network structure, and species topological roles, all of which may have adverse consequences on biodiversity in the forests.
... Thus, they drop to the ground and rot, resulting in great loss of these sugar resources to the environment. This is especially critical considering its high fruit yield (mean of 11.24 tons per hectare) (Peng et al. 2010), and biannual fruiting and ripening patterns (Maan et al. 2020). The rich sugar content of PM fruit presents clues to its potential as a possible feedstock for use in first-generation (1G) bioethanol production. ...
... The ripe fruits of PM were highly juicy, constituting almost half of the fresh fruit weight (Table 1). This confers on it a succulent and delicate structure (Maan et al. 2020), and a consequent increased susceptibility to microbial degradation of its sugars (Choosung et al. 2019). As typical of sugar-based biomasses, prompt harvest, swift juice extraction, and immediate storage of juice under appropriate conditions prior to fermentation are very important steps to ensure sugar preservation (Klasson and Boone 2021). ...
By way of broadening the use of diverse sustainable bioethanol feedstocks, the potentials of Paper mulberry fruit juice (PMFJ), as a non-food, sugar-based substrate, were evaluated for fuel ethanol production. The suitability of PMFJ was proven, as maximum ethanol concentration (56.4 g/L) and yield (0.39 g/g) were achieved within half a day of the start of fermentation, corresponding to very high ethanol productivity of 4.7 g/L/hr. The established potentials were further optimally maximized through the response surface methodology (RSM). At the optimal temperature of 30 °C, yeast concentration of 0.55 g/L, and pH of 5, ethanol concentration, productivity, and yield obtained were 73.69 g/L, 4.61 g/L/hr, and 0.48 g/g, respectively. Under these ideal conditions, diverse metal salts were afterward screened for their effects on PMFJ fermentation. Based on a two-level fractional factorial design, nutrient addition had no positive impact on ethanol production. Thus, under the optimal process conditions, and without any external nutrient supplementation, bioethanol from PMFJ compared favorably with typical sugar-based energy crops, highlighting its resourcefulness as a high-value biomass resource for fuel ethanol production.
Graphical Abstract
... B. papyrifera displays strong vitality and resistance ability (such as under the stress of heavy metals, dehydration and salt and alkali), and is widely used in medicine, as animal feed and for ecological remediation (Si et al., 2018;Ryu et al., 2019;Zhang et al., 2020). B. papyrifera reproduction includes sexual reproduction and asexual reproduction (Maan et al., 2020). Sexual reproduction mainly refers to the germination of seeds. ...
... Because street median and sidewalk trees are often the same age, they offer an opportunity to systematically test different landscape variables such as distances to buildings, building density, or different species of trees. Species-specific life cycle data are valuable for management challenges such as controlling invasions (Maan et al., 2020) and green infrastructure testing such as stormwater retention properties (Houdeshel et al., 2015). Continued development of accelerometer-based study of tree species within and across cities may aid in assessing range shifts for urban planting guides. ...
Trees are bioindicators of global climate change and regional urbanization, but available monitoring tools are ineffective for fine-scale observation of many species. Using six accelerometers mounted on two urban ash trees (Fraxinus americana), we looked at high-frequency tree vibrations, or change in periodicity of tree sway as a proxy for mass changes, to infer seasonal patterns of flowering and foliage (phenophases). We compared accelerometer-estimated phenophases to those derived from digital repeat photography using Green Chromatic Coordinates (GCC) and visual observation of phenophases defined by the USA National Phenology Network (NPN). We also drew comparisons between two commercial accelerometers and assessed how placement height influenced the ability to extract seasonal transition dates. Most notably, tree sway data showed a greenness signal in an urban environment and produced a clear flowering time-series and peak flowering signal (PF), marking the first observations of a flower phenophase using accelerometer data. Estimated start of spring (SOS) from accelerometers and time-lapse GCC were more similar than start of autumn (SOA); accelerometers lagged behind the time-lapse camera dates by three and four days for SOS and 13 and 14 days for SOA for each tree. Estimates for SOS and SOA from accelerometers and time-lapse cameras aligned closely with different NPN phenophases. The two commercial accelerometers produced similar season onset: a difference of 2.4 to 3.8 days for SOS, 2.1 days for SOA, and 0.5 to 2.0 days for PF. Accelerometers placed at the main crown branch point versus higher in the canopy showed a difference of 0.2 to 4.9 days for SOS and -1.5 to 1.7 days for PF. Our results suggest accelerometers present a novel opportunity to objectively monitor reproductive tree biology and fill gaps in phenology observations. Furthermore, widely available accelerometers show promise for scaling up from individual trees to the landscape level to aid forest management and assessing climate change impacts to tree phenology.
Plant life history and functional characteristics play an important role in determining the invasive potential of plant species and have implications for management approaches. We studied the distribution of 24 alien plant taxa in a protected area in relation to different land-uses by applying ordination analyses and generalized linear models. Taxa richness is best explained by the presence of built-up areas, followed by residential areas, marshlands, and agricultural lands with semi-natural formations. The diversity of land-use within the grid cell proved to be an important explanatory factor, being the only significant variable explaining the richness of wood perennials and vines. The richness of annual herbs and seed-dispersed taxa is explained by a similar set of variables, with the exception of residential areas. The richness of invasive species is explained only by agricultural land and the diversity of land-use. The richness of taxa with predominant vegetative dispersal is best explained by built-up, marshland, and seminatural areas along with land-use diversity. When we consider only the presence of plant groups within grid cells, the results are similar. The results of similar studies may provide an important tool for defining sustainable practices and overall conservation management in protected areas.
The annual Namaqualand daisy flowering spectacle is a world-renowned environmental event. Using documentary sources, including newspaper archives from The Rand Daily Mail, Volksblad and Die Burger and social media records from Flickr and iNaturalist, the first long-term phenological dataset spanning 1935–2018 was compiled for the Namaqualand region. The dataset contains first flowering, full bloom and end of bloom dates for the Namaqualand daisies. This study explores shifts in the timing of Namaqualand daisy bloom, and the role of climate in driving these phenological shifts. First flowering and full bloom phenology of the Namaqualand daisies are advancing at statistically significant rates of 2.6 days decade−1 and 2.1 days decade−1 respectively. Climatic data from seven Namaqualand weather stations, collectively spanning 1959–2018, were interrogated. For the periods spanned by both climate and phenology data, the relationships between the two were explored. Increasing temperatures are driving the calculated advances of the daisy flowering dates at statistically significant rates of change ranging from 0.01 to 0.11 days °C−1. The main climate drivers of Namaqualand daisy flowering phenology are winter and spring temperatures, the onset of the winter rainy season during April and May, and total winter precipitation. The rates of advance and climate drivers are broadly consistent with global phenological meta-analyses and records for the Southern Hemisphere. The advances in the timing of Namaqualand daisy flowering will have a significant impact on the tourism sector in the region, as flower viewing tours need to be prearranged months in advance.
In urban environments, anthropogenic influences play an important role in determining the distribution of woody flora and consequently, the propagation of woody invaders. Land-use changes and disturbances associated with urbanization may intensify different invasive aspects of a species. Studying the extent by which invasive species vary from non-invasive species can strengthen our understanding of urban invasions. In this study, we compared leaf litter decomposition between two confamilial exotics, an invasive Broussonetia papyrifera, and a non-invasive Morus alba (both belonging to family Moraceae), growing in urban habitats. Senescent leaves of both the species and soil were collected from five study sites in Chandigarh, India. Litterbags filled with 10 g leaves each were placed in pots containing the soil collected from respective study sites. Mass remaining, decomposition constant, and soil elemental composition were determined after periodic harvesting of the pots. Decomposition was completed within 180 days in B. papyrifera and 330 days in M. alba. Initially, the decomposition rate was low in B. papyrifera; however, a rapid degradation occurred after 90 days. Species, time, and their interaction significantly affected most of the elements in soil, whereas the effect of habitat was not significant. The faster decomposition rate in B. papyrifera may result in greater turnover of nutrients over a shorter time span, thereby, favoring its colonization in the invaded regions. The difference in litter decomposition process explains the invasion success of B. papyrifera over its confamilial species, M. alba, in urban habitats.
The Gauteng City-Region in the northern interior of South Africa hosts one of the world’s largest and most densely vegetated urban forests. The tree species, distributed across pavements, parks and suburban gardens, comprise a range of indigenous and alien species. The most aesthetically distinct of these is Jacaranda mimosifolia (Bignoniaceae), a purple-blossoming tree introduced from Brazil in the 1800s to beautify the cities. The distinct appearance during flowering and their abundance in the Gauteng City-Region has resulting in reporting of peak flowering events in local newspapers throughout the past century. This provides a valuable phenological record, particularly in southern Africa where phenology is seldom recorded. Analysing these reports of Jacaranda mimosifolia flowering, an advance of 2.1 days per decade is calculated for the period 1927–2019. This occurs against a backdrop of statistically significant annual and monthly temperature increases of ∼0.1−0.2 °C/decade for Tmax and ∼0.2−0.4 °C/decade for Tmin, and non-uniform change in rainfall. This phenological advance is most significantly related to winter climatic conditions, including Tmax, rainfall and frost occurrence. The strongest phenological driver is June Tmax, at a rate of 4.3–5.3d/°C across the City-Region. This advance reflects the response of the tree to regional climate warming, which poses threats to the species and the urban forest in the long term when thresholds for adaptation are surpassed.
Broussonetia papyrifera (L.) L'Hér. ex Vent. (common name: paper mulberry; family: Moraceae) is an invasive exotic tree from eastern Asia, which has been introduced to different parts of the world, including India, for both commercial and non-commercial purposes. It has been intentionally planted as an avenue tree in tropical and subtropical urban landscapes. Recently, it has spread beyond original plantings to become invasive in urban areas. The present study was conducted to determine the invasive potential, distribution, and impact of B. papyrifera on understorey vegetation and soil characteristics in a subtropical urban ecosystem in Chandigarh, India. It was observed that both sexual and vegetative reproduction contribute to the invasion success of B. papyrifera. The distribution of B. papyrifera in Chandigarh, India was estimated according to the Importance Value Index, and the 14 study sites were classified into four invasion categories, i.e., uninvaded, sparsely invaded, moderately invaded, and highly invaded. The results revealed that B. papyrifera is rapidly invading the city, particularly at urban-forest interfaces. The impact of B. papyrifera on the alpha diversity of invaded areas was assessed by quantifying the diversity, richness, and evenness of the understorey species. The soil in highly invaded areas was more acidic with greater conductivity, phenolic content, and organic carbon content, implying that either B. papyrifera alters soil physico-chemical properties or prefers to inhabit soil with such characteristics. Invasion of B. papyrifera results in displacement of vegetation either via competitive exclusion or allelopathy. Thus, we advise that conservation managers and government bodies discourage its further cultivation and take necessary actions to control its spread.
A new flavane, bropapyriferol (1), and eleven known ones were isolated from the EtOAc part of Broussonetia papyrifera under the guidance of bioassay. The structure of compound 1 was determined by extensive 1D and 2D NMR, [α]D spectroscopic data and quantum computation. Daphnegiravan F (2) and 5,7,3′,4′-tetrahydroxy-3-methoxy-8,5′-diprenylflavone (3) showed significantly anti-oral microbial activity against five Gram-positive strains and three Gram-negative strains in vitro. Especially, compound 3 was more potent in suppressing Actinomyces naeslundii and Porphyromonas gingivalis (MIC = 1.95 ppm) than the positive control, triclosan.
Graphical Abstract
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Eradication of alien plants is notoriously challenging, however eradication projects reap great biodiversity benefits, particularly on islands. To date only individual plants or small restricted populations have been successfully eradicated from the Southern Ocean Islands (SOI). The next phase in conservation for the region is tackling more widespread, abundant alien plant species. Several on-going and proposed control programs for such weeds exist in the SOI and Antarctic regions. If eradication of a widespread species is to be successful, a number of factors need to be considered. ‘Organisational’ factors such as management agency capacity, resources and the availability of effective control methods are critical to the success of an eradication. ‘Site and species’ factors such as infestation extent, number of discrete populations, dispersal processes and detectability typically show a cumulative effect on success. We assessed the site and species factors for Stellaria media, an alien species on sub-Antarctic Macquarie Island, to determine the feasibility of its eradication from the island. Organisational factors can successfully be met with adequate funding. Site and species factors which reduce the likelihood of eradication included large gross infestation areas, large plants with high reproductive output (precocity or fecundity), dense seed banks, short pre-reproductive period, extended seed longevity and vegetative reproductive capacity. We recommend a small-scale eradication trial for restricted, easily accessible populations of S. media on Macquarie Island to further evaluate the likelihood of broader eradication.
Plant traits such as phenological development, growth rate, stress tolerance and seeds production may play an important role in the process of acclimatisation to new environments for introduced plants. Experiments that distinguish phenotypic plasticity from ecotypic differentiation would allow an understanding of the role of plant traits in the invasion process. We quantified the variation in phenological and overall performance traits associated with the invasion process for three herbaceous species native to Spain and invasive to Chile ( Trifoliumglomeratum , Hypochaerisglabra and Leontodonsaxatilis ). We grew plants from native and exotic populations along rainfall gradients in outdoor common gardens, located in the native and the introduced ranges and measured plant survival, phenology (days to flowering), biomass and seed output. Days to flowering was positively correlated with precipitation of the origin population for T.glomeratum and the native populations of H.glabra , but this pattern was not adaptive, as it was not associated with an increase in performance traits of these species. Phenology may instead reflect ecotypic differentiation to the environmental conditions of the original populations. Comparison between ranges (i.e. performance in both common gardens) was only possible for L.saxatilis . This species showed little variation in phenology and both native and exotic populations had higher fitness in the introduced range. This suggests that plasticity enhances invasiveness through increased propagule pressure in the novel environment. Our findings highlight the utility of common garden experiments in examining patterns of phenological and performance traits that relate to species invasiveness.
Invasive plants often occupy an array of habitats along wide latitudinal scales which differ considerably in climatic conditions and herbivory. Variation in plant traits across latitude may play an important role in invasion success, yet few studies have tested whether there is a latitudinal pattern in invasive plant traits. Here, we sampled individuals of the invasive plant Phytolacca americana at 15 field sites spanning 10° of latitude from 25.72° to 36.15°N in central and southern China. We measured traits related to growth (plant height, canopy width, number of branches and stem diameter), reproduction (fruits per raceme and racemes per plant) and anti-herbivory defense (leaf, stem, root and fruit saponin). Overall, we found no latitudinal patterns for plant size, reproductive output or defense in growth tissues. However, growth architecture was significantly related to latitude: number of stems increased, while stem diameter decreased with increasing latitude. Reproductive architecture was also significantly related to latitude: with increasing latitude, plants produced fewer fruits per raceme, but more racemes per plant. We also found defense in reproductive tissue (fruit saponin) increased with increasing latitude. These findings provide an important latitudinal perspective for resource allocation and adaptive strategy in invasive P. americana that may aid in management recommendations at regional scales.
Broussonetia papyrifera (L.) Vent. (Paper mulberry) is a fast-growing woody perennial [Moraceae] native to southeast Asia and deliberately introduced to Ghana in the Afram Headwaters and Pra-Anum Forest reserves in the late 1960s. The plant has emerged as a major invasive species, and has invaded a vast area of land in the forest zone. The objectives of the study were to assess the distribution of B. papyrifera in southern parts of Ghana and evaluate the effectiveness of possible control strategies for the plant. A survey revealed that the species has spread from the original sites of introduction to other parts of the forest zone. Three treatments including manual uprooting, direct herbicide application and cut-and-spray with herbicide were applied to saplings in experimental plots. Manual uprooting and cut-and-spray treatments effectively suppressed regeneration/ re-sprouting of B. papyrifera for up to 24 weeks. Pole-sized trees of different stump heights and diameter classes treated with systemic herbicide failed to coppice after 24 weeks. The study showed that manually uprooting seedlings and saplings, and cutting followed by squirting the stumps of pole-sized trees with the appropriate chemicals would be effective measure to suppress the growth of B. papyrifera and prevent it from spreading.
The paper mulberry, Broussonetia kazinoki × Broussonetia papyifera, is a species within the family Moraceae, also is an economic and ecological plant. Complete chloroplast genome of paper mulberry was reported in this study. The total genome size was 160,903 bp in length, which is separated by a large single copy (LSC) region and a small single copy (SSC) region (89,220 and 20,079 bp in length, respectively). There were a total of 134 predicted functional genes, including 80 protein-coding genes (PCGs), eight ribosomal RNA (rRNA) genes, and 46 transfer RNA (tRNA) genes. The overall G + C content of the paper mulberry chloroplast genome was 35.74%, while the corresponding values of the LSC, SSC, and IR regions are 33.33%, 28.50%, and 42.72%, respectively. The phylogenetic analysis between Moraceae trees showed chloroplast genome of paper mulberry was closely related to Morus multicaulis.
The invasive tree Solanum mauritianum Scopoli remains one of the world’s most widespread environmental weeds. Despite biocontrol providing one of the few viable long-term solutions to tackling S. mauritianum invasions globally, only South Africa and, more recently, New Zealand, have programmes in place. Ongoing biocontrol efforts against S. mauritianum are reviewed here with particular reference to South Africa. The South African programme has suffered a troubled history, with considerable research efforts culminating in the eventual release and establishment of only two insect agents, Gargaphia decoris Drake and Anthonomus santacruzi Hustache. The difficulties experienced have hindered research into new agents, causing apprehension in using biocontrol internationally. However, recent studies have demonstrated that biocontrol may be deserving of renewed investment, particularly within an integrated management context. In this review, we advocate for the revival of the S. mauritianum biocontrol programme in South Africa, and discuss possible avenues for future research internationally.
Triploid Miscanthus × giganteus (Greef et Deu. ex Hodkinson et Renvoize) is a sterile, perennial grass used for biomass production in temperate environments. While M. × giganteus has been intensively researched, a scale standardizing description of M. × giganteus morphological stages has not been developed. Here we provide such a scale by adapting the widely-used Biologische Bundesanstalt, Bundessortenamt, CHemische Industrie (BBCH) scale and its corresponding numerical code to describe stages of morphological development in M. × giganteus using observations of the “Freedom” and “Illinois” clone in Iowa, USA. Descriptive keys with images are also presented. Because M. × giganteus plants overlap in the field, the scale was first applied to individual stems and then scaled up to assess plants or communities. Of the 10 principal growth stages in the BBCH system, eight were observed in M. × giganteus. Each principal stage was subdivided into secondary stages to enable a detailed description of developmental progression. While M. × giganteus does not have seed development stages, descriptions of those stages are provided to extend the scale to other Miscanthus genotypes. We present methods to use morphological development data to assess phenology by calculating the onset, duration, and abundance of each developmental stage. This scale has potential to harmonize previously described study-specific scales and standardize results across studies. Use of the precise staging presented here should more tightly constrain estimates of developmental parameters in crop models and increase the efficacy of timing-sensitive crop management practices like pest control and harvest.
Considering the importance of ecological and biological traits in imparting invasive success to the alien species, the phenological behaviour of an alien invasive weed Parthenium hysterophorus was documented according to the extended BBCH scale in four different seasons. A phenological calendar was prepared using both two- and three- digit coding system, precisely describing the developmental stages of the weed. The phenological documentation is further supplemented with the dates corresponding to a particular growth stage, pictures of the representative growth stages and meteorological data of all the four seasons. Results revealed that the phenology of the weed altered in response to the changing temperature and humidity conditions but no apparent climatic condition could inhibit its germination or flowering. However, the emergence of inflorescence was highly sensitive to the temperature/photoperiodic conditions. Variations in the phenological traits of P. hysterophorus with changing environmental conditions explain the acclimatisation potential of the weed permitting its vast spread in the non-native regions. Since the given phenological illustrations are accurate, unambiguous and coded as per an internationally recognised scale, they could be exploited for agronomic practices, weed management programmes, and research purposes.
It is presented the results of an expeditionary study , conducted in the south-east part of Romania, soil samples (0-20 cm) under the mais during the growning phase of 4-7 pairs of leaves , have been colected. The investigation methodology included three methods: determining the soil content of mobile Zn, calculating the values of the reaction-mobile phosphates index (RMPI) and zinc deficiency index( ZnDI). The probability of Zinc deficiency assessed by the ZnDI show that 56% of the total samples have a high and very high probability of this phenomenon, 14% in the the class with a medium probability , 16% in the class with low probabiliyy and 14% in improbabile class.
Phenology has achieved a prominent position in current scenarios of global change research given its role in monitoring and predicting the timing of recurrent life cycle events. However, the implications of phenology to environmental conservation and management remain poorly explored. Here, we present the first explicit appraisal of how phenology — a multidisciplinary science encompassing biometeorology, ecology, and evolutionary biology — can make a key contribution to contemporary conservation biology. We focus on shifts in plant phenology induced by global change, their impacts on species diversity and plant–animal interactions in the tropics, and how conservation efforts could be enhanced in relation to plant resource organization. We identify the effects of phenological changes and mismatches in the maintenance and conservation of mutualistic interactions, and examine how phenological research can contribute to evaluate, manage and mitigate the consequences of land-use change and other natural and anthropogenic disturbances, such as fire, exotic and invasive species. We also identify cutting-edge tools that can improve the spatial and temporal coverage of phenological monitoring, from satellites to drones and digital cameras. We highlight the role of historical information in recovering long-term phenological time series, and track climate-related shifts in tropical systems. Finally, we propose a set of measures to boost the contribution of phenology to conservation science. We advocate the inclusion of phenology into predictive models integrating evolutionary history to identify species groups that are either resilient or sensitive to future climate-change scenarios, and understand how phenological mismatches can affect community dynamics, ecosystem services, and conservation over time.
Broussonetia papyrifera
(L.) Vent. (Moraceae) was introduced to Ghana in 1969 and has since become second only to
Chromolaena odorata
as an invasive species in Ghanaian forests. This study determined its ecological traits that enhance its invasion of plant communities. Fruiting and viability patterns were studied through monthly monitoring of 985 trees (≥6 cm gbh) in one forest site. The effect of light on its seed germination was tested in light-proof boxes. Means of propagation were determined by tracking the origin of newly regenerated plants on a newly cleared plot of land that
B. papyrifera
had occupied. It fruited twice a year with one season (January–March) producing more fruits than the other (July-August). Fruiting occurred in trees as small as 9 cm gbh but the percentage of individuals fruiting in each size class increased with tree size. There was a clear pattern of seed viability during the January–March fruiting period. The species did not appear to have a naturally high seed viability with germination always below 50% of each weekly collection. Seed germination was depressed in dark. These results suggest that the species may be competitive in disturbed forest sites and therefore its spread may be aided by forest degradation.
We review the findings of studies carriedout on frugivory and seed dispersal in coastal Tropical Dry Evergreen Forests (TDEF) ofsouthern India, derived largely from studies in Sriharikota (Andhra Pradesh) and Point Calimere (Tamil Nadu). A family-wise list of fruiteating birds and mammals recorded at these sites, the fruit-species eaten and dispersed by them, and the physical traits of fruit species are discussed. Important fruit resources for birds and mammals are highlighted. In total, 34 species of birds of 17 families and 12 species of mammals of 11 families were recorded eating fruits. The major avian frugivores were from the families Pycnonotidae, Sturnidae, Corvidae, and Cuculidae. Among mammals, the major frugivores were from the families Cercopithecidae, Canidae, Viverridae, and Pteropodidae. Birds and mammals in coastal TDEFs utilized fruit from 49 different families. Fruit colour was dominated by red, black, and yellow and fruit type by drupe and berry.
Increasing interest in cryopreservation of dormant buds reveals the need for better understanding of the role of dormancy in cryotolerance. Dormancy stage and low-temperature survival of vegetative apple buds (Malus domestica Borkh.), cultivars 'Sampion' and 'Spartan', collected from orchard were evaluated during three seasons contrasting in temperature and precipitation throughout the arrested plant growth period. During each season, the cultivars differed either in the onset of the endodormancy or in the length of the endodormant period. A simple relation between endodormancy of the buds and their water content was not detected. The cryosurvival of vegetative apple buds of both cultivars correlated with their cold hardening without direct regard to their particular phase of dormancy. The period of the highest bud cryotolerance after low-temperature exposure overlapped with the endodormant period in some evaluated seasons. Both cultivars had the highest cryosurvival in December and January. The presented data were compared with our previous results from a dormancy study of in vitro apple culture. Endodormancy coincided with the period of successful cryosurvival of apple buds after liquid nitrogen exposure, but as such, it was not decisive for their survival and did not limit their successful cryopreservation.
The growth stages of development of many cultivated plants have been described by numerous scientists according to the principles of the extended BBCH scale within the last 19 years. The BBCH scales are now well- known worldwide and are used by research, administration and practise in agriculture and horticulture, as in the phenology as an integrative science in environment, meteorology and climatology.
This fact indicates that the basic objectives and hope have been reached, justifying the practical approach taken by the authors of this scale. The BBCH scale is a contribution to improve the communication between different groups of scientists and to allow the interchange of data and scientific results in a transparent way. The BBCH scales have turned out helpful and practical. The aim to cause the harmonisation in the application of decimal codes for the description of the phenological growth stages of plants and weeds was reached. They also fulfilled the hope of the initiators to contribute with it to the improvement of the international agrarian-scientific and interdisciplinary communication.
This paper will describe the history and background of the BBCH scales. The original publications are described and explained with reference of the original literature sources. The paper will describe the different area of use of the scales and list the different scientific disciplines using them. The worldwide success of the BBCH scales is the work of many scientists around the globe.
Several studies have focused on cold tolerance in multiple regulated levels. However, a genome-scale molecular analysis of the regulated network under the control of transcription factors (TFs) is still lacking, especially for trees. To comprehensively identify the TFs that regulate cold stress response in the paper mulberry and understand their regulatory interactions, transcriptomic data was used to assess changes in gene expression induced by exposure to cold.
Results indicated that 794 TFs, belonging to 47 families and comprising more than 59% of the total TFs of this plant, were involved in the cold stress response. They were clustered into three groups, namely early, intermediate and late responsive groups which contained 95, 550 and 149 TFs, respectively. Among of these differentially expressed TFs, one bHLH, two ERFs and three CAMTAs were considered to be the key TFs functioning in the primary signal transduction. After that, at the intermediate stage of cold stress, there were mainly two biological processes that were regulated by TFs, namely cold stress resistance (including 5 bHLH, 14 ERFs, one HSF, 4 MYBs, 3 NACs, 11 WRKYs and so on) and growth and development of lateral organ or apical meristem (including ARR-B, B3, 5 bHLHs, 2 C2H2, 4 CO-like, 2 ERF, 3 HD-ZIP, 3 YABBYs, G2-like, GATA, GRAS and TCP). In late responsive group, 3 ARR-B, C3H, 6 CO-like, 2 G2-like, 2 HSFs, 2 NACs and TCP. Most of them presented the up-regulated expression at 12 or 24 hours after cold stress implied their important roles for the new growth homeostasis under cold stress.
Our study identified the key TFs that function in the regulatory cascades mediating the activation of downstream genes during cold tress tolerance in the paper mulberry. Based on the analysis, we found that the AP2/ERF, bHLH, MYB, NAC and WRKY families might play the central and significant roles during cold stress response in the paper mulberry just as in other species. Meanwhile, many other TF families previously reported as involving in regulation of growth and development, including ARF, DBB, G2-like, GRF, GRAS, LBD, WOX and YAABY exhibited their important potential function in growth regulation under cold stress.
Longan (Dimocarpus longan) is an important evergreen fruit crop grown in tropical and subtropical climates, with a clear expanding potential, but with a poorly described phenology. In this work, the different phenological growth stages of longan are characterized according to the BBCH (Biologische Bundesanstalt, Bundessortenamt und Chemische industrie) scale. From vegetative bud dormancy to fruit harvest, seven main growth stages are described for bud, leaf and shoot development, inflorescence emergence, flowering, fruit development and fruit maturity. Within them 41 secondary growth stages are described. The BBCH code will be an important tool to assist the development and implementation of longan management protocols and to standardize observations made in different edaphoclimatic and experimental conditions.
Broussonetia papyrifera (L.) Vent. (Moraceae), or paper mulberry, is a species of cultural importance
in South East Asia, East Asia and the Pacific. Originally from mainland South East Asia or East
Asia, this plant was introduced into the Pacific range by prehistoric Austronesian voyagers. We used
non-coding internal transcribed spacer (ITS) sequences of nuclear ribosomal DNA and inter-simple
sequence repeat (ISSR) on 79 samples of B. papyrifera from different islands of Remote Oceania,
and South East Asia and East Asia. Our results show an absence of genetic diversity in the
introduced range of Remote Oceania, with the sole exception of Hawaii. By contrast, Asian samples
show genetic diversity. The data obtained suggest a prehistoric human-mediated introduction of
this species from East Asia to Remote Oceania and a second, possibly historic, human-mediated
introduction to Hawaii.
The knowledge of phenotypic variation in the European range of the highly allergenic Ambrosia artemisiifolia L. (common ragweed) is not entirely complete, even though it is an invasive species of utmost concern. We hypothesized the prevalence of phenotypic differentiations between common ragweed populations in the introduced range, and we assumed that those differentiations were related to environmental conditions at the points of origin. Using a common garden experiment, we investigated biomass allocation, growth rates, and flowering phenology of 38 European common ragweed populations originating from a major geographical gradient. We observed considerable phenotypic variation in growth parameters and flowering phenology, e.g. mean aboveground biomass varied from 23.3 to 47.3 g between the populations. We were able to relate most measured traits with environmental parameters prevailing at the points of origin. For example, early growth of ruderal populations was highly correlated with temperature and precipitation at the point of origin. Late growth and flowering phenology were highly correlated with latitude, i.e. individuals from northern populations grew smaller and flowered and dispersed their pollen and seeds up to 5 weeks earlier than individuals from southern populations. We also found a longitudinal gradient in flowering phenology which has not yet been described. The existence of such a high variability in the introduced range may facilitate further range expansion. We suggest that the correlation with environmental variables rests upon genetic variation possibly due to adaptations to the respective environment. To clarify if such adaptation results from multiple events of introduction or as evolutionary response after introduction, genetic investigations are needed.
Alien and exotic plant invasions are threatening the floral diversity around the globe and affect ecological processes. Weed invasion has been documented in North-West Pakistan. A total of 16 weeds were reported as invasive. These were Xanthium strumarium, Ipomoea eriocarpa, Alternanthera pungens, Trianthema portulacastrum, Tagetes minuta, Imperata cylindrica, Amaranthus hybridus subsp. hybridus, Robinia pseudo-acacia, Broussonetia papyrifera, Ailanthus altissima, Pistia stratiotes, Phragmites australis, Parthenium hysterophorus, Cannabis sativa, Galium aparine and Emex spinosus. Among these Robinia pseudo-acacia, Broussonetia papyrifera and Ailanthus altissima are trees and were purposely introduced as they later became invasive. They were aggressive in nature and replaced or suppressed the local vegetation. Their distribution, history of invasion and management has been discussed here. The behaviour and association of the 36 problem weeds with different crops has also been outlined as they perspired from the farmers.
Remote sensing image analysis is increasingly being used as a tool for mapping invasive plant species. Resulting distribution maps can be used to target management of early infestations and to model future invasion risk. Remote identification of invasive plants based on differences in spectral signatures is the most common approach, typically using hyperspectral data. But several studies have found that textural and phenological differences are also effective approaches for identifying invasive plants. I review examples of remote detection of invasive plants based on spectral, textural and phenological analysis and highlight circumstances where the different approaches are likely to be most effective. I also review sources and availability of remotely sensed data that could be used for mapping and suggest field data collection approaches that would support the analysis of remotely sensed data. Remote mapping of biological invasions remains a relatively specialized research topic, but the distinct cover, morphology and/or seasonality of many invaded versus native ecosystems suggests that more species could be detected remotely. Remote sensing can sometimes support early detection and rapid response directly, however, accurately detecting small, nascent populations is a challenge. However, even maps of heavily infested areas can provide a valuable tool for risk assessment by increasing knowledge about temporal and spatial patterns and predictors of invasion.
The original Thornthwaite and Mather method, proposed in 1955 to calculate a climatic monthly cyclic soil water balance, is frequently used as an iterative procedure due to its low input requirements and coherent estimates of water balance components. Using long term data sets to establish a characteristic water balance of a location, the initial soil water storage is generally assumed to be at field capacity at the end of the last month of the wet season, unless the climate is (semi-) arid when the soil water storage is lower than the soil water holding capacity. To close the water balance, several iterations might be necessary, which can be troublesome in many situations. For (semi-) arid climates with one dry season, Mendonça derived in 1958 an equation to quantify the soil water storage monthly at the end of the last month of the wet season, which avoids iteration procedures and closes the balance in one calculation. The cyclic daily water balance application is needed to obtain more accurate water balance output estimates. In this note, an equation to express the water storage for the case of the occurrence of more than one dry season per year is presented as a generalization of Mendonça's equation, also avoiding iteration procedures.
Phenological documentation and plant invasion are key contemporary issues in the biological sciences. Recognizing this, the present paper describes the phenological stages of an invasive species, Sapium sebiferum (L.) Roxb. A tree of the species was marked, and daily visits were made for recording its phenology. The Biologische Bundesanstalt, Bundessortenamt and CHemical industry (BBCH) scale was used for documenting the same. Of the total ten principal stages, eight were observed in the species. These stages started with bud development (stage 01) in the month of March and ended with leaf fall (stage 97) in the month of December. Descriptions of the phenological stages and their dates are provided in the text. It is hoped that such a phenological scale will be helpful in managing plant invasion.
Following its introduction in the late 1960s, Broussonetia papyrifera L. Vent. Moraceae (paper mulberry) has emerged as a major exotic invasive species in Ghana's forest ecosystems. This study was carried out to assess the effects of B. papyrifera invasion on community composition in forest and forest-savannah transition ecosystems. Comparative and removal experiments were conducted in paired B. papyrifera invaded versus uninvaded plots. In the comparative assessment, species composition was found to be similar in both invaded and uninvaded plots. However, relative per cent cover of resident species and guilds including Chromolaena odorata, indigenous broadleaves and indigenous grasses were significantly lower in invaded plots. Seven months after B. papyrifera was experimentally removed from invaded stands, cover by indigenous broadleaves increased by 35%, as against only 5% in control plots at the forest site. However, at the transition site, the increase in per cent cover of indigenous broadleaves (18%) was not significantly different from control (2.5%) plots. We conclude that B. papyrifera has the capacity to reduce the abundance of indigenous broadleaf species, although its removal is more likely to favour regeneration in a forest than a forest-savannah transition ecosystem.
The wide knowledge gaps in invasion biology research that exist in the developing world are crucial impediments to the scientific
management and global policymaking on biological invasions. In an effort to fill such knowledge gaps, we present here an inventory
of the alien flora of India, based on systematic reviews and rigorous analyses of research studies (ca. 190) published over
the last 120 years (1890–2010 AD), and updated with field records of the last two decades. Currently, the inventory comprises
of 1,599 species, belonging to 842 genera in 161 families, and constitutes 8.5% of the total Indian vascular flora. The three
most species-rich families are Asteraceae (134 spp.), Papilionaceae (114 spp.) and Poaceae (106 spp.), and the three largest
genera are Eucalyptus (25 spp.), Ipomoea (22 spp.), and Senna (21 spp.). The majority of these species (812) have no report of escaping from cultivation. Of the remaining subset of 787
species, which have either escaped from intentional cultivation, or spread after unintentional introduction, casuals are represented
by 57 spp., casual/naturalised by 114 spp., naturalised by 257 spp., naturalised/invasive by 134 spp., and invasive by 225
spp. Biogeographically, more than one-third (35%) of the alien flora in India has its native ranges in South America, followed
by Asia (21%), Africa (20%), Europe (11%), Australia (8%), North America (4%); and cryptogenic (1%). The inventory is expected
to serve as the scientific baseline on plant invasions in India, with implications for conservation of global biodiversity.
ABSTRACT The ecology of seed dispersal by vertebrates has been investigated extensively over recent decades, yet only limited research has been conducted on how suites of invasive plants and frugivorous birds interact. In this review, we examine how plant fruit traits (morphology, colour and display, nutritional quality, accessibility and phenology), avian traits (fruit handling techniques, gut passage time and effect, bird movements and social behaviour and dietary composition) and landscape structure (fruit neighbourhood, habitat loss and fragmentation and perch tree effects) affect frugivory and seed dispersal in invasive plants. This functional approach could be used to develop generic models of seed dispersal distributions for suites of invasive plant species and improve management efficiencies. Four broad research approaches are described that could direct management of bird-dispersed invasive plants at the landscape scale, by manipulating dispersal. First, research is needed to quantify the effect of biological control agents on dispersal, particularly how changes in fruit production and/or quality affect fruit choice by frugivores, dispersal distributions of seed and post-dispersal processes. Second, we explore how seed dispersal could be directed, such as by manipulating perch structures and/or vegetation density to attract frugivorous birds after they have been foraging on invasive plant fruits. Third, the major sources of seed spread could be identified and removed (i.e. targeting core or satellite infestations, particular habitats and creating barrier zones). Fourth, alternative food resources could be provided for frugivores, to replace fruits of invasive plants, and their use quantified.
ABSTRACT The traditional approach to understanding invasions has focused on properties of the invasive species and of the communities that are invaded. A well-established concept is that communities with higher species diversity should be more resistant to invaders. However, most recently published field data contradict this theory, finding instead that areas with high native plant diversity also have high exotic plant diversity. An alternative environment-based approach to understanding patterns of invasions assumes that native and exotic species respond similarly to environmental conditions, and thus predicts that they should have similar patterns of abundance and diversity. Establishment and growth of native and exotic species are predicted to vary in response to the interaction of plant growth rates with the frequency and intensity of mortality-causing disturbances. This theory distinguishes between the probability of establishment and the probability of dominance, predicting that establishment should be highest under unproductive and undisturbed conditions and also disturbed productive conditions. However, the probability of dominance by exotic species, and thus of potential negative impacts on diversity, is highest under productive conditions. The theory predicts that a change in disturbance regime can have opposite effects in environments with contrasting levels of productivity. Manipulation of productivity and disturbance provides opportunities for resource managers to influence the interactions among species, offering the potential to reduce or eliminate some types of invasive species.
The spread of many invasive plants is facilitated through seed dispersal by frugivorous animals. The effectiveness of various frugivores as dispersers of the seeds of Melia azedarach, a highly invasive alien tree species, was evaluated in South Africa in savanna and bushveld vegetation. During 264 h of observation, seven bird species and one bat species were recorded foraging on fruiting trees of M. azedarach. The most common visitors were the dark-capped bulbul (Pycnonotus barbatus) followed by Wahlberg's epauletted fruit bat (Epomophorus wahlbergi), but both species droppednearly as many seeds as they dispersed. Knysna turaco (Tauraco corythaix) dispersed the highest number of fruits per minute, but occurred in low abundance in our study sites. Seed germination differed significantly between de-pulped fruits and untreated fruits after 2 mo, but was similar after 4 mo. Germination success did not differ between animal-handled and hand-depulped fruits. In contrast to the high germination success in the greenhouse, seedlings showed very low recruitment in the field. Thus, M. azedarach seems likely to benefit from frugivores (particularly dark-capped bulbul and Wahlberg's epauletted fruit bat) dispersing seeds to suitable microsites.
1 Species attributes have been used to explain invasion patterns assuming the prevalence of biological mechanisms, although this approach often suffers several methodological and conceptual limitations, such as local idiosyncrasies, differences among habitats, phylogenetic constraints and insufficient sample size.
2 The relative importance of 15 species traits for explaining the abundance over 350
naturalized alien plant species was assessed across five Mediterranean islands (Corsica, Crete, Majorca, Malta and Sardinia). A comparative analysis accounting for phylogeny was used to examine variation in semi-quantitative estimates of species abundance in comparable habitats across the five island floras.
3 Species were divided into those with affinity for semi-natural, agricultural and ruderal
habitats. Both vegetative and reproductive attributes were evaluated for individual islands
and averaged across all islands.
4 Vegetative propagation, large leaf size, summer flowering, long flowering period and
dispersal by wind or vertebrates were positively associated with average alien abundance
across all five islands. Fewer significant trends were found in island-specific patterns.
5 The relative importance of a few reproductive traits is reflected in over-representation
of Caryophyllales, Asterales and Poales (late flowering, large seed size and anemochory).
Although significant covariation in traits was found there was no evidence for welldefined
invasive syndromes.
6 Succulence was important in ruderal habitats, long flowering period in agricultural
habitats and vertebrate seed dispersal in semi-natural habitats, suggesting that empty
niches, avoidance of competitors and exploitation of mutualists, respectively, are
important.
7 The study highlights the importance of estimating invasion success across a wide
region, but analyses of specific invasion stages are also needed. Reproductive traits,
which may be more relevant for long-distance colonization, and vegetative traits, which
determine local dominance and persistence, were, nevertheless, both related to abundance within islands.
Biological invasion caused by the non-indigenous plant species have been considered as one of the major threat to the native vegetation and its diversity at local, regional and global level and its effect on native forest ecosystem is regarded as one of the most critical issues confronting environmental conservationists. This study addresses the influence of Broussonetia papyrifera on the native scrub forest at the Himalayan Foothills, Islamabad, Pakistan and its relationship with ecological gradients which are important in terms of its spatial distribution. Floristic species composition and environmental factors were measured from 77 plots from two sites of the scrub forest at the lower elevation of Margalla Hills National Park Islamabad. Agglomerative hierarchical Cluster Analysis (CA) was used for species assemblage patterns and ordination analyses such as Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA) was used to establish the relationship with the underlying ecological gradients. CA divided the plots into three vegetation zones: a vegetation zone comprised of species of native scrub forest dominated by Acacia modesta; a transition vegetation zone where B. papyrifera was present either in scattered form amongst the scrub forest species or showed patchy distribution and invasive vegetation zone dominated by B. papyrifera. Man Whitney U-test was used to find out if vegetation zones identified by CA could be significantly different from each other based on the measured environmental factors. Factor Analysis (FA)/Principal Components Analysis (PCA) were used to identify set of environmental factors/predictors, which can best discriminate vegetation zones. FA/PCA (raw varimax rotated) on the environmental factors renders three varifactors with eigenvalues higher than 1.0 accounting for over 72% of total variance. Multivariate analyses indicated that the spatial distribution of B. papyrifera is related to edaphic factors such as the soil texture, organic matter and moisture contents. The distribution was insensitive to the topographic factors. The probable consequences of B. papyrifera invasion for future scrub forest composition and plant species diversity are also discussed. The findings of this research will be used in formulating scientifically sound management and conservation strategy for the forest ecosystems of the Margalla Hills National Park Islamabad.
This study aims to investigate the anaerobic digestion (AD) performance of Broussonetia papyrifera, a wide distributed nitrogen-rich and lignocellulosic-like plant, for methane production. The fermentation was conducted with the volatile solid (VS) concentration at 0.5%, 1.0%,1.5%,2.0% and 4.0% under 37°C and 55°C for 30 days, respectively. Results suggested that the feedstock concentration at 2.0% and fermentation temperature at 55°C was optimal for the AD treatment of Broussonetia papyrifera. A maximal specific methane yield was achieved at 277.72 ± 15 mL/g VS, which was 94.71% higher than that for the maximum specific methane under the thermophile condition, likely because that the C/N was more suitable compared with other lignocellulosic biomass. A kinetic study suggested that the modified Gompertz equation was reliable (determination coefficients R² greater than 0.97) to describe the kinetic behavior of anaerobic digestion of Broussonetia papyrifera. In general, Broussonetia papyrifera was proved to be a suitabe feedstock for anaerobic digestion for methane production.
Since Schinus molle (Peruvian pepper tree) was brought to Southern California, the dioecious tree has been widely adopted in urban forests and has become invasive. Prior to our study, it was unknown whether S. molle influences plant species in its understory through allelopathy as it does in other geographic areas. The present study sought to determine if S. molle has negative effects on three native and three non-native, invasive understory species. For two separate experiments seeds of six plant species were sowed in mulch (leaf litter) and soil collected from both genders of S. molle. Because a prior study showed that native succulents were most inhibited by males, we expected male mulch and soil would affect native and invasive species more than that of females; however, this prediction was not supported.
Male leaf litter of S. molle stimulated the shoot biomass for Amsinckia intermedia, Bromus madritensis, Brassica nigra, and Stipa pulchra. Male soils reduced the shoot emergence of B. madritensis by 34%, however, both genders of soil did not influence the root and shoot biomass of any species. Additionally, field observations in three urban nature reserves recorded 20 native and 10 invasive plant species beneath S. molle canopies. The present study showed S. molle did not have the same influence on species as previously reported for native succulents.
Soil nitrogen-fixing bacterial communities (SNB) can increase the level of available soil N via biological N-fixation to facilitate successful invasion of several invasive plant species (IPS). Meanwhile, landscape heterogeneity can greatly enhance regional invasibility and increase the chances of successful invasion of IPS. Thus, it is important to understand the soil micro-ecological mechanisms driving the successful invasion of IPS in heterogeneous landscapes. This study performed cross-site comparisons, via metagenomics, to comprehensively analyze the effects of Solidago canadensis invasion on SNB in heterogeneous landscapes in urban ecosystems. Rhizospheric soil samples of S. canadensis were obtained from nine urban ecosystems [Three replicate quadrats (including uninvaded sites and invaded sites) for each type of urban ecosystem]. S. canadensis invasion did not significantly affect soil physicochemical properties, the taxonomic diversity of plant communities, or the diversity and richness of SNB. However, some SNB taxa (i.e., f_Micromonosporaceae, f_Oscillatoriaceae, and f_Bacillaceae) changed significantly with S. canadensis invasion. Thus, S. canadensis invasion may alter the community structure, rather than the diversity and richness of SNB, to facilitate its invasion process. Of the nine urban ecosystems, the diversity and richness of SNB was highest in farmland wasteland. Accordingly, the community invasibility of farmland wasteland may be higher than that of the other types of urban ecosystem. In brief, landscape heterogeneity, rather than S. canadensis invasion, was the strongest controlling factor for the diversity and richness of SNB. One possible reason may be the differences in soil electrical conductivity and the taxonomic diversity of plant communities in the nine urban ecosystems, which can cause notable shifts in the diversity and richness of SNB.
Paper mulberry is a valuable woody species with a good chilling tolerance. In this study, phosphoproteomic analysis, physiological measurement and mRNA quantification were employed to explore the molecular mechanism of chilling (4 ?C) tolerance in paper mulberry. After chilling for 6 hours, 427 significantly changed phosphoproteins were detected in paper mulberry seedlings without obvious physiological injury. When obvious physiological injury occurred after chilling for 48 hours, a total of 611 phosphoproteins were found to be significantly changed at the phosphorylation level. Several protein kinases, especially CKII, were possibly responsible for these changes, according to conserved sequence analysis. The results of GO analysis showed that phosphoproteins were mainly responsible for signal transduction, protein modification and translation during chilling. Additionally, transport and cellular component organization were enriched after chilling for 6 and 48 hours, respectively. Based on the protein-protein interaction network analysis, a protein kinases and phosphatases hub protein (P1959) was found to be involved in cross-talk between Ca2+, BR, ABA and ethylene-mediated signaling pathways. We also highlighted the phosphorylation of BpSIZ1 and BpICE1 possibly impacted on the CBF/DREB-responsive pathway. From these results, we developed a schematic for the chilling tolerance mechanism at phosphorylation level.
Tree phenology describes complex tree growth and developmental processes. Phenological scales are a useful tool for understanding tree growth/establishment and to evaluate tree phenology management practices under urban forestry conditions. Scales such as (1) the BBCH scale (Biologische Bundesantalt, Bundessortenamt und Chemische Industrie) and a (2) landmark scale (developed by the authors) were used to characterize the phenological changes occurring in the capuli cherry Prunus serotina subsp. capuli (Cav.) McVaugh growing under tropical conditions in Bogotá, Colombia. The BBCH scale is an applicable tool that describes whole tree canopy phenological events, and the landmark scale is a useful descriptor of individual asynchronous stems, which occur as ephemeral flushes at different portions of the canopy. Our results depicted several principal advantages to using the BBCH scale. The landmark scale described fewer vegetative, reproductive, and fruiting stages when compared to the BBCH scale. The landmark scale included the timing of each stage/event and the BBCH failed to do so. Thus, both scales differ in number of stages, coding system, timing of each individual stage, and synchronous (BBCH scale) vs asynchronous (Landmark scale) events. Both scales are applicable, useful and meaningful to the study site and the field of urban forestry. This study helps to expand our knowledge of the capuli cherry's phenology and urban forestry applications.
The accurate prediction of winter injury caused by low-temperature events is a key component of the effective cultivation of woody and herbaceous perennial plants. A common method employed to visualize geographic patterns in the severity of low-temperature events is to map a climatological variable that closely correlates with plant survival. The U.S. Department of Agriculture Plant Hardiness Zone Map (PHZM) is constructed for that purpose. We present a short history of PHZM development, culminating in the recent production of a new, highresolution version of the PHZM, and discuss how such maps relate to winterhardiness per se and to other climatic factors that affect hardiness. The new PHZM is based on extreme minimum-temperature data logged annually from 1976 to 2005 at 7983 weather stations in the United States, Puerto Rico, and adjacent regions in Canada and Mexico. The PHZM is accessible via an interactive website, which facilitates a wide range of horticultural applications. For example, we highlight how the PHZM can be used as a tool for site evaluation for vineyards in the Pacific northwestern United States and as a data layer in conjunction with moisture-balance data to predict the survival of Yugoslavian woody plants in South Dakota. In addition, the new map includes a zip code finder, and we describe how it may be used by governmental agencies for risk management and development of recommended plant lists, by horticultural firms to schedule plant shipments, and by other commercial interests that market products seasonally.
Phenology, the timing of annually recurrent reproductive biological events, provides a critical signal of climate variability and change effects on plants. Considerable work over the past five decades has quantified the extent to which plant phenophases are responding to local changes in temperature and rainfall. Originally undertaken through the analysis of ground-based phenological observations, the discipline has more recently included phenophase indicators from satellite images and digital repeat photography. With research advances it has become evident that the responses of plant phenology to climate variability and change are both location- and species-specific. The extent to which plants are affected by changes in temperature and rainfall, their intrinsic adaptation capacity, will ultimately determine the potential for sustained ecological stability and food security. We review methodological approaches to plant phenological-climate change over time, analyse the regions and phenophases for which climate variability demonstrates a clear causal role, and finally reflect on the applications of phenological climate change investigations in broader biogeographical contexts.
A study was carried out in Panama on Ficus insipida and F. yoponensis (subgenus Pharmacosycea), F. obtusifolia and F. costaricana (subgenus Urostigma), Cecropia insignis and Poulsenia armata. Overall, phenological activities were more pronounced in the drier half of the year, but at least some leaf shed, leaf flush and fruit production took place throughout the year in most species. As a family, as species and, frequently, as individuals, these Moraceae exhibited phenological traits that would tend to make their new leaves and/or fruits available to primary consumers in this forest for much or all of an annual cycle. The reproductive phenology of Ficus species in this study contrasted with that of C. insignis and P. armata in that individuals of the Ficus species could produce massive fruit crops at any time of year. This temporal flexibility with respect to the timing of fruit crops appears to relate, at least in part, to the obligate mutualism of fig trees with wasp pollinators. -from Author
To elucidate climate-driven changes in leaf-out phenology and their implications for species invasions, we observed and experimentally manipulated leaf out of invasive and native woody plants in Concord, MA, USA. Using observations collected by Henry David Thoreau (1852-1860) and our own observations (2009-2013), we analyzed changes in leaf-out timing and sensitivity to temperature for 43 woody plant species. We experimentally tested winter chilling requirements of 50 species by exposing cut branches to warm indoor temperatures (22°C) during the winter and spring of 2013. Woody species are now leafing out an average of 18 d earlier than they did in the 1850s, and are advancing at a rate of 5 ± 1 d °C(-1) . Functional groups differ significantly in the duration of chilling they require to leaf out: invasive shrubs generally have weaker chilling requirements than native shrubs and leaf out faster in the laboratory and earlier in the field; native trees have the strongest chilling requirements. Our results suggest that invasive shrub species will continue to have a competitive advantage as the climate warms, because native plants are slower to respond to warming spring temperatures and, in the future, may not meet their chilling requirements.
Vegetation develops in response to many different stimuli including climatic, edaphic, and cultural conditions. The degree to which the distribution of vegetation can be explained on the basis of climatic conditions depends in part on the proper selection of active climatic factors. Temperature and precipitation by themselves are poor descriptors of climate. Potential evapotranspiration, water surplus, and water deficit (combined in a moisture index) are found to be more useful. An analysis of the vegetation distribution in conterminous United States shows that the Thornthwaite moisture index and annual potential evapotranspiration are not only able to differentiate among the mid-latitude grassland, forest, and desert biochores but also to provide climatic limits for formation classes within each of the biochores. For example, it is possible to identify on the basis of numerical data an oak-hickory climate as distinct from the birch-maple, and a bunch grass climate distinct from the sagebrush. The problem of non-climatically controlled vegetation associations such as the low latitude pines and savanna are also discussed.
Bitou bush, Chrysanthemoides monilifera (L.) Norlindh ssp. rotundata (DC.) Norlindh, is an invasive weed of coastal vegetation types in eastern Australia. It produces fleshy fruits, which are dispersed by birds and mammals. Compared with a range of vertebrate-dispersed fruits of native plant species that co-occur with naturalised C. monilifera, or occur elsewhere in south-eastern Australia, C. monilifera fruits and endocarps are intermediate in all dimensions and in the ratio of endocarp to pulp. C. monilifera fruits contain moderate quantities of sugars, but low quantities of protein and fat relative to many native fruits. Phenology, however, substantially distinguishes C. monilifera from co-occurring native plant species. C. monilifera produces fruits throughout the year, with the peak of production occurring in autumn to winter, a time when few native species in coastal vegetation produce fruits. Additionally, 9 of the 12 native species that do fruit, at least partly, over this period, differ substantially from C. monilifera in fruit morphology. C. monilifera, along with other invasive species, has substantially altered the temporal pattern of fruit availability in coastal vegetation. These fruiting characteristics have rendered C. monilifera fruits attractive to frugivores and have contributed to its successful spread.
six phenological patterns are recognized in the flora of a tropical savanna in the Venezuelan Llanos. The dominant perennial grasses and sedges have an alternation between a period of intensive tiller production, shoot growth and sexual reproduction during the rainy season, and a phase of semirest during the dry season, when shoots decline and tiller development decreases to a minimum. An opposite strategy is displayed by the tree species; they have a phase of full leaf development and maximum assimilation during the rainy season, but without any shoot growth or leaf formation, while in the dry season they renew the foliage and flower. Annuals constitute a numerically-significant part of the savanna flora, and have been ascribed to two different phenological groups. The long-cycle annuals form one group and these have an active life cycle of 6 to 7 months, coincident with the rainy season; the other group is formed by the short-cycle annuals or ephemerals, which complete their cycle in only 2 to 4 months during the latter part of the rainy season. Another phenological strategy is displayed by those species which enter into a dormancy phase during drought, when all their above-ground organs dry out; their active phenophases occur during the rainy period. The sixth phenological group is formed by the evergrowing the everflowering plants, i.e. those savanna species without a manifest seasonality. In the semi-deciduous tropical forest which occurs in the same area, two phenological strategies were discerned. The first is displayed by deciduous trees which stay leafless for a part of or for the entire dry season, and which put out a new crop of leaves either just before the onset of rains, or at the beginning or the rainy season. Different reproductive patterns are found in this group, with various species flowering at different times, either during the wet or the dry season. The second strategy in this forest is comprised of evergreen and brevidecidous species which renew their foliage during drought, when both opposite phenophases (leaf flush and leaf drop) proceed simultaneously. Flowering also takes place during the dry season, but only in the brevideciduous species is it directly related to leaf renewal. Considering the total flora of both communities, a major peak of flowering in the middle of the rainy season characterizes the savanna, while the forest has two equally important flowering peaks, one in each season. A discussion of the possible role of various environmental impulses in plant phenology in this region is attempted, considering all seasonal factors, such as daylength, rainfall seasonality, thermoperiodism, extreme temperatures, insolation and radiation. Finally, the conditions favouring the existence and success of each phenological strategy are considered, together with a critical examination of the seasonal characteristics of the two econsystem.
Information on the geographical distribution of plant invasion has been recorded in detail in some areas of the world; however, in large regions such as South America there are a few, if any, records of the spread of alien plants and invasive species and even less information about their effects on ecosystems at different levels of organization. This study examines the extent to which woody species introduced during the last centuries are invading the Rolling Pampa (which is typical of the entire region of the Argentina pampas) and discusses whether this invasion is related to the species’ genetics or to environmental factors. All woody species were surveyed along landscape corridors (highways and intersecting secondary dirt roads and streams), as well as in farmed fields under three different tillage systems: zero tillage in the entire field for all crops in the rotation (where tillage was replaced by a presowing herbicide application), zero tillage for selected crops, and conventional tillage. Landscape corridors along the roads had been invaded by 40 woody species (mostly trees). On the farmed land, fields under the zero tillage farming system were invaded by seven woody species (three tree species and four shrubs). With zero tillage for select crops only, woody species richness was reduced to three (one tree and two shrub species). In the conventional tillage, there were only three invading species, all shrubs. In both the roadside and riparian corridors, the species with the highest constancy values were Gleditsia triacanthos L., Morus alba L., and Melia azedarach L. In both types of zero tillage farmed fields, M. alba was absent, but G. triacanthos and M. azedarach remained the species with the highest constancy values. Both genetic and ecological factors were important determinants for the invasion of the pampas by woody species. The woody invasion process has reached a point at which the pampean grasslands on the better-drained soils will no longer be restored to a grassland biome without human intervention.
1. Exotic annual plants are an increasingly important ecological issue and new, creative approaches to management are required. In desert ecosystems of the southwestern USA, the forbs Brassica tournefortii, Erodium cicutarium and Schismus spp. dominate and alter native annual communities. Hand weeding B. tournefortii is currently the most common control method employed, but weeding is inadequate and expensive for managing large-scale invasions. New methods must be developed to conserve and restore desert ecosystems.
2. Exotic annuals in desert systems have rapid germination and phenology compared to natives, indicating that a window for selective control of exotic annuals may occur immediately after exotic seedling emergence. We tested the role of timing in control methods by comparing a cotyledon-stage glyphosate application to a bolting-stage application and to hand weeding B. tournefortii, plus an untreated check. Treatments were tested at two sites dominated by either exotic or native annuals and followed for 2 years; early application was repeated the second year. Cover and richness were evaluated during seedling and peak flowering stages underneath and between shrubs.
3. Early glyphosate application did not affect native cover, but did reduce exotic cover. Late herbicide negatively impacted both exotics and natives. Natives had little positive response, and then only through hand weeding under shrubs, but the same treatment caused an increase in the exotic E. cicutarium.
4.Synthesis and applications. The rapid phenology of exotic annuals may be exploited to control exotics while minimizing impacts on native plants in desert communities. This approach may be useful for other invasions in other ecosystems by species with rapid, early germination, or may act as a supplement to improve the efficacy of existing management regimes.
Aim We aim to report what hyperspectral remote sensing can offer for invasion ecologists and review recent progress made in plant invasion research using hyperspectral remote sensing.Location United States.Methods We review the utility of hyperspectral remote sensing for detecting, mapping and predicting the spatial spread of invasive species. We cover a range of topics including the trade-off between spatial and spectral resolutions and classification accuracy, the benefits of using time series to incorporate phenology in mapping species distribution, the potential of biochemical and physiological properties in hyperspectral spectral reflectance for tracking ecosystem changes caused by invasions, and the capacity of hyperspectral data as a valuable input for quantitative models developed for assessing the future spread of invasive species.Results Hyperspectral remote sensing holds great promise for invasion research. Spectral information provided by hyperspectral sensors can detect invaders at the species level across a range of community and ecosystem types. Furthermore, hyperspectral data can be used to assess habitat suitability and model the future spread of invasive species, thus providing timely information for invasion risk analysis.Main conclusions Our review suggests that hyperspectral remote sensing can effectively provide a baseline of invasive species distributions for future monitoring and control efforts. Furthermore, information on the spatial distribution of invasive species can help land managers to make long-term constructive conservation plans for protecting and maintaining natural ecosystems.