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Research in large, long-term tropical forest plots
Abstract
The past 15 years has seen the creation oflarge (>/16 ha) permanent inventory plots in each of the major tropical forest formations of the world. Currently, six such plots have been fully mapped, and five more and under way. A standardized methodology is used at all sites - a complete census of all trees and saplings down to 1 cm in diameter - thus assuring strict comparability between sites and allowing the development of general models for the dynamics of tropical forests. The inventories aim to gather demographic information on individual tree species, to provide long-term information on forest composition so that future changes can be detected, to estimate the economic value of forest resources, to generate models of sustainable extraction, and to provide data on underused native species for use in reforestation or plantation forestry. The plots also provide data from undisturbed forest to serve as a control for anthropological and management studies of harvested forests.
... acutiserrata, Quercus variabilis, Pistacia chinensis, and Carpinus turczaninovii [53][54][55], as shown in Table 1. Between June to September 2020, 10 permanent forest plots, each covering an area of 100 m × 100 m, were established in the Taihang Mountains Macaque National Nature Reserve following the large-scale forest plot methodology outlined by Condit [56]. Each plot was subdivided into 25 subplots of 20 m × 20 m using a total station, resulting in a total of 250 subplots. ...
... Between June to September 2020, 10 permanent forest plots, each covering an area of 100 m × 100 m, were established in the Taihang Mountains Macaque National Nature Reserve following the large-scale forest plot methodology outlined by Condit [56]. Each plot was subdivided into 25 subplots of 20 m × 20 m using a total station, resulting in a total of 250 subplots. ...
Estimates of tree species diversity via traditional optical remote sensing are based only on the spectral variation hypothesis (SVH); however, this approach does not account for the vertical structure of a forest. The relative height (RH) indices derived from GEDI spaceborne LiDAR provide vertical vegetation structure information through waveform decomposition. Although RH indices have been widely studied, the optimal RH index for tree species diversity estimation remains unclear. This study integrated GF-1 optical imagery and GEDI LiDAR data to estimate tree species diversity in a warm temperate forest. First, random forest plus residual kriging (RFRK) was employed to achieve wall-to-wall mapping of the GEDI-derived indices. Second, recursive feature elimination (RFE) was applied to select relevant spectral and LiDAR features. The random forest (RF), support vector machine (SVM), and k-nearest neighbor (kNN) methods were subsequently applied to estimate tree species diversity through remote sensing data. The results indicated that multisource data achieved greater accuracy in tree species diversity estimation (average R² = 0.675, average RMSE = 0.750) than single-source data (average R² = 0.636, average RMSE = 0.754). Among the three machine learning methods, the RF model (R² = 0.760, RMSE = 2.090, MAE = 1.624) was significantly more accurate than the SVM (R² = 0.571, RMSE = 2.556, MAE = 1.995) and kNN (R² = 0.715, RMSE = 2.084, MAE = 1.555) models. Moreover, mean_mNDVI, mean_RDVI, and mean_Blue were identified as the most important spectral features, whereas RH30 and RH98 were crucial features derived from LiDAR for establishing models of tree species diversity. Spatially, tree species diversity was high in the west and low in the east in the study area. This study highlights the potential of integrating optical imagery and spaceborne LiDAR for tree species diversity modeling and emphasizes that low RH indices are most indicative of middle- to lower-canopy tree species diversity.
... In accordance with the construction standard of the CTFS, a long-term fixed m toring point of 240 m and 200 m of 4.8 hm 2 was established in the Baiyunshan Forest tional Park [19]. The long-term fixed monitoring plots of 4.8 hm 2 were divided into 12 m × 20 m samples (400 m 2 per sample square) ( Figure 1). ...
... In accordance with the construction standard of the CTFS, a long-term fixed monitoring point of 240 m and 200 m of 4.8 hm 2 was established in the Baiyunshan Forest National Park [19]. The long-term fixed monitoring plots of 4.8 hm 2 were divided into 120 20 m × 20 m samples (400 m 2 per sample square) ( Figure 1). ...
Soil bacteria are an important part of the forest ecosystem, and they play a crucial role in driving energy flow and material circulation. Currently, many uncertainties remain about how the composition and distribution patterns of bacterial communities change along altitude gradients, especially in forest ecosystems with strong altitude gradients in climate, vegetation, and soil properties. Based on dynamic site monitoring of the Baiyun Mountain Forest National Park (33°38′–33°42′ N, 111°47′–111°51′ E), this study used Illumina technology to sequence 120 soil samples at the site and explored the spatial distribution mechanisms and ecological processes of soil bacteria under different altitude gradients. Our results showed that the composition of soil bacterial communities varied significantly between different altitude gradients, affecting soil bacterial community building by influencing the balance between deterministic and stochastic processes; in addition, bacterial communities exhibited broader ecological niche widths and a greater degree of stochasticity under low-altitude conditions, implying that, at lower altitudes, community assembly is predominantly influenced by stochastic processes. Light was the dominant environmental factor that influenced variation in the entire bacterial community as well as other taxa across different altitude gradients. Moreover, changes in the altitude gradient could cause significant differences in the diversity and community composition of bacterial taxa. Our study revealed significant differences in bacterial community composition in the soil under different altitude gradients. The bacterial communities at low elevation gradients were mainly controlled by stochasticity processes, and bacterial community assembly was strongly influenced by deterministic processes at middle altitudes. Furthermore, light was an important environmental factor that affects differences. This study revealed that the change of altitude gradient had an important effect on the development of the soil bacterial community and provided a theoretical basis for the sustainable development and management of soil bacteria.
... Given the superlative nature of tropical plant diversity, attempts to explain the origins and maintenance of such diversity have been a central focus of ecological research [4,5]. In documenting tropical diversity, substantial efforts have been made to conduct thorough surveys of plant communities for this purpose, especially since the advent of the 50-ha plot network coordinated by the Center for Tropical Forest Science [6]. However, these and other comprehensive surveys typically overlook "small" plants, opting to use 1 cm diameter at breast height (dbh) in the case of CTFS, or 10 cm dbh in other surveys [7] as the minimum size cutoff for inclusion in forest censuses. ...
... The use of standardized, spatially explicit sampling designs of woody plant communities such as "Gentry transects" [1,14], and high-resolution forest dynamics plots [6], have facilitated fine-grain characterization of overstory community composition in tropical forests. However, analogous methods have seldom been employed for understory plants in tropical rain forests (see [15,16]). ...
Lowland tropical rainforests harbor the most diverse plant communities in the world, but the herbaceous plants of the understory are often overlooked. To address this knowledge gap, we asked to what extent the understory herbaceous community contributes to the species richness and phylogenetic diversity of plant communities by surveying a neotropical rainforest at Los Tuxtlas, Mexico. We used Gentry transects to characterize the woody overstory community, and line-intercepts within the same transects to survey understory herbs and subshrubs. We also used published phylogenies to calculate community phylogenetic diversity with and without the understory stratum. We found that the understory contained a diverse (23 species, or 22.1% of all species surveyed) and phylogenetically distinct plant community dominated by aroids (13 species) and ferns (4 species). Inclusion of the understory stratum increased total species richness by 28.4% but increased phylogenetic diversity by 41.4%. Additionally, in contrast to temperate forests, the understory plant community was much less diverse than the overstory, which contained 81 species > 1 cm dbh (77.9% of all species surveyed). This survey adds to the hitherto small body of literature comparing understory and overstory strata in tropical rainforests and reveals previously overlooked patterns of floristic diversity.
... Understanding monodominant tropical forests' responses under different drivers of change is more important than ever (Muvengwi et al., 2020), and long-term permanent-plot monitoring is regarded as one of the best approaches to monitor biodiversity and ecological phenomena (Gross et al., 2018;Prach and Walker, 2020), in both spatial and temporal scale, because trees have a long lifespan and because changes resulting from post-disturbance succession would be gradual (Vale et al., 2015). In the absence of long-term data (greater than 40 years) (Condit, 1995;Ediriweera et al., 2020;Sheil, 2001), monitoring 64 permanent plots spread over Isoberlinia-woodlands, on a medium-term (2006-2020) is likely to provide insight in this plant community spatio-temporal dynamics as compared to the less than ten years or even intra-year monitoring periods which are frequent in many West African countries. ...
... In accordance with the protocol established for the 50 hm 2 plot in Panama in 1980 [37][38][39][40], two dynamic monitoring plots, each with an area of 1 hm 2 , were established on Diaoluo Mountain, Hainan Island, from August 2023 to January 2024 ( Figure 1C). Polyvinyl chloride (PVC) tubes were installed at 10 m intervals within the sample plots, and elevation data for each of these intervals were recorded. ...
Despite extensive research on tree species diversity in tropical rainforests, the differences in diversity between lowland and montane rainforests, as well as the underlying mechanisms, remain unclear. This study utilizes tree inventory data from two dynamic monitoring sample plots, each with an area of 1 hm², established in the lowland rainforest and montane rainforest regions of Diaoluo Mountain, Hainan Island. We analyzed the composition, diversity, spatial distribution patterns, and interspecific relationships within the tree communities. In total, 154 tree species with DBH > 3 cm were recorded in lowland rainforests, and 119 were recorded in montane rainforests, with lowland rainforests harboring 51 rare species compared to 40 rare species in montane rainforests. The distribution pattern of small trees (with DBH ≤ 7.5 cm) exhibited clustering at a small scale but random distribution at a larger scale. This phenomenon was more prevalent in tropical lowland rainforests, indicating that the negative density dependence effect is more pronounced in lowland rainforests compared to montane rainforests. Moreover, a higher proportion of negative associations and lower niche overlaps were observed in the lowland rainforest compared to the montane rainforest, suggesting that niche differentiation among tree species is more pronounced in the lowland rainforest. In conclusion, the more intense negative density dependence effect and niche differentiation are the primary factors contributing to the higher tree species diversity observed in lowland rainforests.
... Forest ecology has focused on trees because they dominate carbon, biomass, and financial evaluations (Braun, 1950;Richards, 1952;Spurr and Barnes, 1973;Condit, 1995;Linares-Palomino et al., 2009;Lewis et al., 2009;Muller, 2014). However, other plant growth forms contribute significantly to forest composition, structure, biodiversity, function, and faunal habitat (Johansson, 1974;Gentry and Dodson, 1987;Schnitzer and Carson, 2000;Gilliam, 2014;Thrippleton et al., 2016). ...
Herbaceous plants are an essential component of forest diversity and driver of ecosystem processes. However, because the growth forms and life-history strategies of herbaceous plants differ from those of woody plants, it is unclear whether the mechanisms that drive patterns plant diversity and community structure in these two plant groups are the same. In this study, we determined whether herb and woody plant communities have similar patterns and drivers of alpha- and beta-diversity. We compared species richness, distribution, and abundance of herbs to woody seedlings in a 20-ha Donglingshan warm-temperate forest (Donglingshan FDP), China. We also determined whether variation in patterns of species richness and composition are better explained by environmental or spatial variables. Herbaceous plants accounted for 72% of all species (81 herbaceous, 31 woody) recorded. Alpha- and beta-diversity were higher in herbs than in woody seedlings. Although alpha-diversity of herbs and woody seedlings was not correlated across the site, the local-site contributions to beta-diversity for herbs and woody seedlings were negatively correlated. Habitat type explained slightly more variation in herb community composition than in woody seedling composition, with the highest diversity in the low-elevation slope. Environmental variables explained the variation in species richness and composition more in herbaceous plants than in woody seedlings. Our results indicate that different mechanisms drive variation in the herb and woody seedling communities, with herbs exhibiting greater environmental sensitivity and habitat dependence. These findings contribute to the better understanding of herbaceous plant diversity and composition in forest communities.
... It allowed us to more intuitively analyze the independent effects of rock exposure ratio on EMF, and all the descriptive statistics of environmental variables are in Table S1. There are 25 dynamic monitoring sample plots with specifications of 20 m × 20 m according to the technical specification of CTFS sample survey (Condit 1995), and then divided into 16 subplots of 5 m × 5 m for detailed vegetation surveys. Based on the monitoring criteria for fixed samples, all woody plants with a diameter at breast height (DBH) greater than or equal to 1 cm were measured individually, recording the species name, crown width, height, and DBH. ...
As the climax community of karst in southwest China without human disturbance, the mechanisms through which biodiversity maintains ecosystem multifunctionality (EMF) in evergreen and deciduous broad‐leaved mixed forest are still unclear. This study employed structural equation modeling to analyze the correlations between EMF and three key variables: plant diversity, soil microbial diversity, and rock exposure ratio within this karst forest. Plant and soil microbial diversity were the main biotic drivers of EMF. Within these biotic factors, soil microbial diversity provided a preferable explanation for EMF compared to plant diversity, with fungal diversity and the co‐occurrence network complexity playing dominant roles. Functional, species, and phylogenetic diversity indices of plant explain the changes in EMF better than the community‐weighted mean of traits, indicating that the niche complementarity hypothesis holds greater relevance in explaining the biodiversity‐maintenance mechanism of EMF. Moreover, the rock exposure ratio directly affects EMF as well as indirectly through plant diversity. Collectively, soil microbial diversity, plant diversity, and rock exposure ratio account for 87% of the variability in EMF. Specifically, plant diversity, fungal diversity, and its co‐occurrence network complexity exerted a positive and direct impact on EMF, while bacterial diversity mainly affected EMF by positively contributing to fungal co‐occurrence network complexity. These findings emphasized the significance of comprehensive protection of aboveground and underground biodiversity and have strengthened our comprehension of the biodiversity‐maintenance mechanisms of EMF in karst forests.
... Temporal variation in wood productivity and mortality has been explained in part by the effects of climate on tree growth and mortality, although making such links is challenging given the five-year census intervals. Both mortality and diameter growth rates were elevated during the first census interval of 1982-1985, especially for larger trees; this interval included a major drought associated with a strong El Niño event (Condit, 1995;Feeley et al., 2007b;Condit et al., 2017;Meakem et al., 2018). Most studies do not attempt to calculate biomass stocks or fluxes for the first census (1982) and first census interval, because all of the trees, including buttressed trees, were measured in diameter at 1.3 m in the first census, but the one study that does so estimates both productivity and mortality fluxes were highest in this census interval (Meakem et al., 2018). ...
Tropical forest biomass is a globally important carbon stock with an uncertain future under climate change. Our understanding of tropical forest aboveground biomass stocks and fluxes has been advanced by studies on the Barro Colorado Island (BCI) 50-ha forest plot, where all trees larger than 1 cm in diameter have been measured approximately every five years since 1982. BCI studies introduced new methods for estimating biomass stocks as well as fluxes associated with tree growth and mortality and for quantifying associated uncertainty. Aboveground biomass stocks and fluxes on the BCI plot exhibited strong spatial variation in relation to gap dynamics and weak systematic variation among topographically defined habitats. Biomass fluxes varied strongly among census intervals, but there was no directional trend in biomass stocks. Compared with plot studies in other Latin American tropical forests, BCI is close to the median in stocks and woody productivity and in the 23rd percentile for net flux.
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... Information regarding recruitment and size-specific growth and mortality rates are essential for sustainable forest management (Condit, 1995). Condit et al. (1993) provided a detailed analysis of diameter growth and mortality of Prioria on the BCI 50-ha plot. ...
Monodominant tropical forests, in which one tree species dominates most of the canopy, provide a strong contrast to the exuberant diversity of most tropical forests. In Neotropical lowlands, most such low-diversity forests occur under seasonally flooded conditions. Prioria copaifera Griseb., an economically important timber tree species, forms monodominant stands in seasonally flooded conditions and is also frequent in well-drained sites, including Barro Colorado Island (BCI). Research on BCI has contributed to a better understanding of the demography and physiology of this species, and the mechanisms underlying its monodominance. Long-standing hypotheses explaining monodominance in flooded forests have been based on species’ ability to withstand anoxic conditions during inundation. Monodominance by Prioria, however, is achieved by its ability to withstand alternating flooding and drought conditions. Prioria’s large seeds may provide the resources to construct deep roots, and Prioria seedlings are able to maintain root growth and depth during flooding at early establishment, thus enabling better water access during dry conditions.
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... Despite this richness in species and morphological diversity, most research in forest ecology has focused primarily on trees. Trees are assumed to contribute significantly to ecosystem processes, such as carbon sequestration and plant biomass production (Condit 1995, Lewis et al. 2009, Lutz et al. 2021. However, other growth forms, including epiphytes, lianas, vines, shrubs, and small understorey trees, also play important roles in ecosystem functioning (Pócs 1980, Clark et al. 2005, Adams et al. 2016, Schnitzer 2018. ...
Assessing variation in root functional traits may offer novel insights into plant adaptations to changing environmental conditions. However, such studies, particularly on epiphytic species in tropical ecosystems, are still limited. Previous research has suggested that precipitation has a major impact on epiphyte survival and thus can be considered a candidate driver of epiphytic root trait variation, though compelling evidence is lacking. In this study, we investigated variation in 19 root functional traits in 43 epiphytic (36 species) and 14 terrestrial (7 species) orchids along an elevational gradient in Colombia and examined whether this variation is associated with differences in abiotic conditions. Contrary to previous studies, our findings did not associate trait variation with precipitation but revealed strong correlations with solar radiation, temperature, and water vapour pressure. The variation was particularly pronounced in traits related to the velamen radicum. Epiphytic and terrestrial orchids showed similar responses despite their different growth habits. Overall, these patterns suggest that higher sunlight and temperature conditions lead both orchid types to allocate more resources to root structures that mitigate abiotic stress, and highlight the role of other environmental factors in driving root trait variability.
... For the study, forest dynamics plots (FPDs) were established randomly within each of the four forest vegetation types, adhering to the standard methodologies of the Center for Tropical Forest Science (CTFS) [38] between April 2018 and July 2019. A total of 200 plots, each measuring 20 m × 20 m, were set up. ...
Functional traits are pivotal for understanding the functional niche within plant communities. Yet, the relationship between the functional niches of typical forest plant communities across different climatic zones, as defined by functional traits, and their association with community and phylogenetic structures remains elusive. In this study, we examined 215 woody species, incorporating 11 functional traits spanning leaf economy, mechanical support, and reproductive phenology, gathered from forests in four climatic zones from tropical, subtropical, warm-temperate to cold-temperate zones in China and supplemented by the literature. We quantified the functional niche hypervolume (FNH), reflecting the multidimensional functional niche variability. We then probed into the correlation between the FNH and community and phylogenetic structures of forests. Our findings reveal that species richness significantly influences the geographic variance of functional niche space in forest vegetation across different climatic zones. Specifically, a community’s species richness correlates positively with the functional niche breadth occupied by the community species. The FNH of woody plants across diverse forest types shows significant associations with both the mean phylogenetic distance (MPD) and the mean nearest phylogenetic taxon distance (MNTD) of the communities. There is a progressive increase in tropical rainforest (TF), subtropical evergreen deciduous broad-leaved mixed forest (SF), and warm-temperate coniferous broad-leaved mixed forest (WF), followed by a decline in the cold-temperate coniferous forest (CF). This pattern suggests potential environmental filtering in CF, which may constrain the spatial extent of plant functional niches. Our research underscores the substantial variability in the FNH across China’s typical forest vegetation, highlighting the complex interplay between functional traits, community richness, and phylogenetic distance.
... In our 4 ha study plot, the designated study scales were relatively small compared to the BCI forest [42]. Our findings also indicated that negative density dependence among species with similar or closely related phylogenetic relationships leads to mutual exclusion, contributing to the observed phylogenetic overdispersion structure of the community to some extent. ...
Understanding the maintenance of diversity and the assembly of communities is a primary concern in community ecology. This study explored the phylogenetic structure of an evergreen broadleaved tree community in Con Dao National Park, Vietnam. The survey, conducted in December 2023, encompassed all tree individuals with a diameter at breast height (DBH) ≥ 2.5 cm within a 4-ha study plot. These individuals were identified by species name, and their DBH was measured. Subsequently, a community phylogenetic tree was constructed using the Phylomatic online platform. The 4-ha study plot was subdivided into there different subplots based on three spatial scales (25 m × 25 m, 50 m × 50 m, and 100 m × 100 m) and all trees were classified into three different DBH classes (2.5 cm ≤ DBH < 10 cm representing small trees; 10 cm ≤ DBH < 20 cm as medium trees; and DBH ≥ 20 cm as large trees). The net relatedness index (NRI) and net nearest taxon index (NTI) were utilized to evaluate the phylogenetic structure and infer ecological processes. Our findings revealed a consistent decrease in both NRI and NTI with increasing spatial scales and tree sizes. These results suggest an overdispersed phylogenetic structure within the community across different spatial scales and tree sizes. Additionally, negative density dependence was found to have a pronounced effect on the phylogenetic structure, with a more significant impact on tree individuals from small and medium DBH classes than large ones. This study underscores the significance of phylogenetic density dependence as a primary mechanism governing species diversity and shaping the community structure of evergreen broadleaved forests in Vietnam.
... Where previous surveys have been conducted, resurveying has proven to be a powerful approach to understand long-term trends in forest communities (Condit 1995). It was therefore the objective of this study to revisit vegetation plots previously established by Wirawan (1978) and Welton (1993) to document if/how indigenous and endemic Hawaiian plant species' respective abundances have changed, and how those changes are related to abiotic conditions in these plots. ...
Endemic island plant species under threat due to anthropogenic activities may be more susceptible to decline than their indigenous counterparts. Our study aimed to determine whether endemic and indigenous plant cover in Hawaiian forests have been differentially affected by resource availability, disturbance, and invasion over time. We resurveyed 25 plots (400 m² each) across gradients of elevation, precipitation, slope, and understory light availability in forested conservation areas on the island of Oʻahu, Hawaiʻi, USA. We assessed how these abiotic factors relate to absolute cover (previous, current, and change over time) of endemic and indigenous Hawaiian plants, as well as that of non-native species. Endemic species had a net loss of cover (−45%) since previous surveys 27 to 45 years earlier, while indigenous species had a net gain (+ 29%), as did non-natives (~ 1%). Endemic species cover was associated with higher elevations in both prior surveys and in 2018, and with steeper plot slopes in prior surveys. However, change in endemic cover over time was negatively correlated with slope, likely due to landslide disturbance or the proliferation of shade-tolerant invaders in low-light conditions where no disturbance was evident. Change in endemic species cover over time was not clearly related to resource availability (light and precipitation). Given the differences in responses of endemic and indigenous species to abiotic conditions, and that the endemic species in this study were more susceptible to decline than indigenous species, the results of this study indicate that generalizations about natives as a single group can be misleading.
... In our 4 ha study plot, the designated study scales were relatively small compared to the BCI forest [42]. Our findings also indicated that negative density dependence among species with similar or closely related phylogenetic relationships leads to mutual exclusion, contributing to the observed phylogenetic overdispersion structure of the community to some extent. ...
Understanding the maintenance of diversity and the assembly of communities is a primary concern in community ecology. This study explored the phylogenetic structure of an evergreen broadleaved tree community in Con Dao National Park, Vietnam. The survey, conducted in December 2023, encompassed all tree individuals with a diameter at breast height (DBH) ≥ 2.5 cm within a 4-ha study plot. These individuals were identified by species name, and their DBH was measured. Subsequently, a community phylogenetic tree was constructed using the Phylomatic online platform. The 4-ha study plot was subdivided into there different subplots based on three spatial scales (25 m × 25 m, 50 m × 50 m, and 100 m × 100 m) and all trees were classified into three different DBH classes (2.5 cm ≤ DBH < 10 cm representing small trees; 10 cm ≤ DBH < 20 cm as medium trees; and DBH ≥ 20 cm as large trees). The net relatedness index (NRI) and net nearest taxon index (NTI) were utilized to evaluate the phylogenetic structure and infer ecological processes. Our findings revealed a consistent decrease in both NRI and NTI with increasing spatial scales and tree sizes. These results suggest an overdispersed phylogenetic structure within the community across different spatial scales and tree sizes. Additionally, negative density dependence was found to have a pronounced effect on the phylogenetic structure, with a more significant impact on tree individuals from small and medium DBH classes than large ones. This study underscores the significance of phylogenetic density dependence as a primary mechanism governing species diversity and shaping the community structure of evergreen broadleaved forests in Vietnam.
... Previous studies have examined the spatial distribution of species on a large scale and their relationship to biodiversity conservation [15,[17][18][19][20]. These studies generally found a significant correlation between the diameter at breast height (DBH) and the age of individuals of the same species in the same living environment [21,22]. ...
Analyzing the spatial patterns and associations among tree species may help to elucidate the importance of the ecological processes behind population formation and the mechanisms of species coexistence. To explore this mechanism, we mapped and studied eight dominant tree species in Korean pine broad-leaved mixed forests in a temperate forest region in Jilin Province, Northeast China. The spatial distribution patterns and spatial associations of the eight dominant tree species at different life history stages and spatial scales were analyzed using the second-order spatial point pattern method based on pair correlation functions. The results indicated the following: (1) The diameter class structure of all individuals in the plots showed an obvious “L” shape, indicating that the community was well regenerated and belonged to a growing stand. (2) The distribution of trees was affected by scale, size, and habitat heterogeneity. The degree of aggregation decreased as the diameter class increased. (3) Out of the 56 pairs of individuals, a small number showed a significant correlation, while most were negatively correlated. It is concluded that seed dispersal limitations, competitive ability, and topography and light requirements may influence the spatial distribution and association of species to maintain species coexistence and diversity in Korean pine broad-leaved mixed forests. The results can provide insights into the ecological processes of population assembly, the mechanisms of species coexistence, and the relationship between forest management and restoration.
... The BDGS plot was established in 2011 following the standards set by the Center for Tropical Forest Science (Condit, 1995). The first census was completed in 2011, involved the tagging, measurement, identification, and mapping of over 180,000 free-standing individuals with diameter at breast height (DBH) of ≥ 1 cm, belonging to 232 species, 114 genera, and 53 families (Qin, et al. 2018). ...
It is well known that evergreen and deciduous species possess different functional traits and utilize different strategies in growth and adaptation to environments. However, little work has been done to elucidate whether leaf habits mediate the effect of trait-environment interactions on plant performance. In this study, our subjective was to illuminate whether relative growth rate of deciduous and evergreen species is influenced by multiple trait-environment interactions. We conducted measurements on eight leaf traits of 1230 individuals belonging to 25 species in a subtropical evergreen and deciduous broad-leaved mixed forest. Additionally, we collected data on topographic factors, edaphic variables and competition index. Subsequently, we employed generalized linear mixed model to analyze plant relative growth rate, considering high-order trait-environment interactions for both evergreen and deciduous species. We also visualized the effects of these interactions on growth patterns. Our results showed that leaf habits were divided by trait PC 1 (41.8%) which was related to leaf lifespan and resource acquisition. Evergreen species tended to have greater interspecific variation compared to deciduous species. Notably, the inclusion of trait-environment interactions significantly improved growth predictions for both leaf habits, although explanatory power of deciduous models was always higher than that of evergreen species. Furthermore, we observed variability in the effects of trait-environment interactions on plant performance varied between leaf habits, leading to different optimal models for each leaf habit, even when they shared similar trait-environment context. These results indicated that difference of life history strategies between leaf habits could be reflected by trait-environment interactions. We emphasized the importance of leaf habits in explaining forest productivity and functions, and future research should focus on the effects of leaf habits on other demographic metrics to understand species coexistence in mixed forests.
... We adhered to the guidelines set by the Center for Tropical Forest Science (CTFS; http://www.ctfs.si.edu/, accessed on 1 September 2019) and the Chinese Forest Biodiversity Monitoring Network (CForBio; http://www.cfbiodiv.org/, accessed on 1 September 2019) to assemble long-term, large-scale forest data from the tropics [43]. ...
(1) Background: Understanding the relationship between community assembly and species coexistence is key to understanding ecosystem diversity. Despite the importance of wood-boring longhorn beetles (Cerambycidae) in forests, factors affecting their population dynamics, species richness, and ecological interactions remain underexplored. (2) Methods: We surveyed cerambycid beetles and plants within five plots each across three transects in tropical rainforests and temperate forests of Yunnan, China, known for its rich biodiversity and varied elevation gradients. We explored a range of analytical tools, including α-diversity comparisons, distance-decay relationships, redundancy analysis, β-dissimilarity metrics, and various neutral community model analyses. (3) Results: The results revealed a stark contrast between the two forest types: the tropical rainforests hosted 212 Cerambycidae and 135 tree species, whereas the temperate forests had only 16 Cerambycidae and 18 tree species. This disparity was attributed to differences in environmental heterogeneity and dispersal limitations. In temperate forests, pronounced environmental variability leads to steeper distance-decay relationships and reduced α-diversity of Cerambycidae, implying stronger dispersal constraints and weaker plant–beetle associations. Conversely, the more homogenous tropical rainforests exhibited stochastic processes that enhanced Cerambycidae diversity and plant–beetle interactions. (4) Conclusions: Our findings underscore that environmental heterogeneity, dispersal limitations, and host-specificity are pivotal in shaping biodiversity patterns in Cerambycidae, with significant variations across climatic zones.
... In 2014, we established a 12 hm 2 secondary evergreen broad-leaved forest dynamic monitoring plot in the Guanshan Nature Reserve, according to the Centre for Tropical Forest Science (CTFS) sample plot survey method [42]. The southwest corner of the plot serves as the origin (28 • 33 ′ 25 ′′ N; 114 • 34 ′ 40 ′′ E), with the highest elevation at 645.0 m and the lowest at 444.1 m, resulting in a relative elevation difference of 200.9 m. ...
Neighborhood competition influences tree growth, which can affect species composition and community succession. However, there is a lack of understanding regarding how dominant tree species at different successional stages of forest communities respond in terms of crown architecture and functional traits during their growth process to neighborhood competition. In this study, we analyzed the responses of average annual basal area increment (BAI), crown architecture, and leaf functional traits of early-successional species (Cunninghamia lanceolata and Pinus massoniana), transitional species (Alniphyllum fortunei and Choerospondias axillaris), and late-successional species (Elaeocarpus duclouxii and Castanopsis carlesii) to neighbor competition in a secondary evergreen broad-leaved forest. We found that the BAI of all species is negatively correlated with competition intensity. Notably, early-successional and transitional species exhibited a more rapid decline in growth rates compared to late-successional species in response to increased competition. Among these tree species, the response of crown structure to neighbor competition exhibited variation. Early-successional and transitional species displayed a negative correlation between the competition index and crown area (CA)/diameter, while a positive correlation emerged between the lowest branch height (LBH)/height. Conversely, late-successional species followed the opposite trend. In terms of leaf functional traits, specific leaf area (SLA) showed heightened sensitivity to neighborhood competition, with a positive correlation between SLA of all tree species and the competition index. Furthermore, water use efficiency (WUE) demonstrated negative correlations with the competition index in early-successional and transitional trees, while a positive correlation emerged with late-successional trees. These findings suggest that early-successional and transitional trees prioritize vertical canopy growth, whereas late-successional trees tend to favor horizontal canopy expansion in response to neighboring competition. Additionally, early-successional and transitional trees experience more significant suppression of radial growth rate. Our research contributes to a deeper understanding of the underlying mechanisms driving changes in species composition and community succession.
... The plot supports predominantly old-growth semideciduous moist tropical forest [15,21]. The plot has been censused every 5 years since 1980, with every tree (>1 cm diameter at breast height) mapped and identified to species level [22,23]. The census in 2015 recorded 297 species among 207,719 individuals [24,25]. ...
Soil phosphorus (P) partitioning could contribute to species diversity and structure in plant communities, but field-scale evidence for P partitioning remains scarce. We hypothesized that the presence of P partitioning could be inferred from statistical associations between the spatial distributions of plants and chemical forms of bioavailable soil P. We investigated this in a diverse tropical tree community on Barro Colorado Island, Panama. We quantified potentially bioavailable forms of soil P by extraction in 2 mM citric acid followed by treatment with phosphatase enzymes. We then linked these P forms to the distribution of 189 tree species in a 50 ha forest dynamics plot by testing species–P associations against null models of random dispersal. We found that 20% of tree species were significantly (α = 0.05) associated with the depletion of at least one soil organic P fraction, although around half of these associations might be false rejections of the null hypothesis due to type I error. Species in the Fabaceae (legumes), which are known to express high rates of phosphatase in their roots, were most frequently associated with soil P fractions. We interpret our findings as evidence of widespread P partitioning at the community scale, affecting a relatively small proportion of tree species in this moderately fertile forest. We predict that stronger evidence of partitioning will be found at sites with lower P availability.
... Plots were set up in these four patches, and the plots encompassed all T. Table S1). The plots were established following guidelines from the Center for Tropical Forest Science [35], and the altitude, slope gradient, slope aspect, litter depth, and humidity were recorded for each [36][37][38]. Each of the four plots was further subdivided into 10 m × 10 m subplots. ...
Tertiary relict plants are of great scientific value in the study of flora evolution, angiosperm systems, and ancient origins. Paying attention to their spatial patterns can better reflect the change dynamics of the species to implement targeted protection countermeasures. In this study, we investigated the spatial patterns of Tetracentron sinense Oliver, a tertiary relict plant, and further studied the intra- and interspecific and environmental factors impacting the patterns. The results reveal that most of the individuals of T. sinense were distributed in the 1700–1800 m altitudinal belt, and they were highly aggregated at a small scale. The young trees showed a positive interaction with adult trees. The dominant species showed a positive interaction with T. sinense; the interaction gradually became non-significant or negative as the scale increased. The key abiotic factors affecting the distribution of T. sinense were altitude, litter depth, zinc, and calcium. These results highlight the intra- and interspecific interactions and environmental factors influencing the spatial pattern of T. sinense. Our results provide new insights into tertiary relict species’ spatial patterns and nearline factors. Moreover, these findings have relevant implications for conserving and managing tertiary relict plants in a constantly fragmented habitat.
... For the purpose of a vegetation resource survey, we established thirty-five 20 m × 20 m sampling quadrats in the Baidan and Bannan areas, each of which was divided into 16 sub-samples of 5 m × 5 m in area (Condit, 1995). According to the monitoring standards for fixed plots, we surveyed all woody plants with a diameter at breast height ≥1 cm in each plot. ...
Introduction
Plant diversity and soil chemical properties are important factors affecting the plant growth. We sought to compare the explanatory rates of diversity and soil chemical properties in explaining the variation of basal area in karst forests, and also sought to compare the relative importance of the niche complementarity and mass ratio hypotheses.
Methods
On the basis of linear regression and structural equation modelling, we examined the correlation between the basal area of plant communities and species diversity, functional diversity, phylogenetic diversity, the community-weighted mean (CWM) of traits, and soil chemical properties, using data obtained from 35 monitoring plots in southwest China.
Results
Species, functional, and phylogenetic diversities were all significantly correlated with the basal area of the plant community, among the indices of which, Faith’s phylogenetic diversity was found to have the greatest explanatory power for basal area. These plant diversity indices can better explain the variation in basal area than the CWM of traits, suggesting the niche complementarity hypothesis is more applicable than the mass ratio hypothesis. Moreover, soil chemical properties also have an equal important impact. Different chemical properties were found to show significant positive correlations with basal area, and their total effects on basal area were shown to be greater than the CWM of traits.
Discussion
Attention should be paid to diversity and soil chemical properties. This study provides theoretical guidance for understanding biodiversity maintenance mechanisms and protecting karst forests.
... The BDGS plot was established in 2011 following the standards set by the Center for Tropical Forest Science (Condit, 1995). The first census was completed in 2011, involved the tagging, measurement, identification, and mapping of over 180,000 free-standing individuals with diameter at breast height (DBH) of ≥ 1 cm, belonging to 232 species, 114 genera, and 53 families (Qin, et al. 2018). ...
... environmental degradation during the industrial revolution (FOSTER, 1999), sampling bias, and the number of publications found for the temperate region, which is more than triple the number of articles recorded for the tropics (n = 856). Another factor is the lack of standardized long-term field data to effectively test biotic homogenization in the tropical region (CONDIT, 1995;HARRIS et al., 2021). ...
A systematic literature review was conducted on biotic homogenization in tropical forests and its consequences for the diversity of tree communities. We evaluated articles indexed in Scopus® and Web of Science® from 1945 to 2022. The selection of publications was carried out using the Rayyan platform. The bibliometric method used for database mapping was co-word analysis in VOSviewer software. We distinguished three lines of research on biotic homogenization: invasion ecology of species; environmental and anthropogenic factors; and functional and phylogenetic diversity. The most studied and perhaps the most affected component was the taxonomic component. Biotic homogenization events are widely distributed throughout the tropical region, with the most affected forest type being tropical rainforest, and the main cause identified was land use change related to anthropogenic degradation. Studies on biotic homogenization in the tropics have intensified in the last decade and have resulted in significant advances in understanding this process, such as the realization that hyperdiverse environments are susceptible to biotic homogenization, which can be mediated by generalist native species. We observed the emergence of another component of diversity to be included in the homogenization concept: homogenization of ecological interactions.
... si. edu/) instructions for the assembly of long-term, large-scale forest data from the tropics 40 and with the Chinese Forest Biodiversity Monitoring Network (http:// www. cfbio div. ...
A long-debated question in ecology is whether the hyper-diversity of tropical plant-feeding insects is a direct consequence of high tropical plant diversity or should be attributed to increases in host plant specialization. In this study, we used Cerambycidae (the wood-boring longhorn beetles whose larval stages feed on the xylems of trees and lianas) and plants as study materials to explore which hypothesis is more favoured. Multiple analyses were used to show the differences in host specificity of Cerambycidae in tropical and subtropical forests. From these analyses, we found that the alpha diversity of beetles in tropical forests was significantly higher than that in subtropical forests but not in plants. The relationship between plants and beetles was also closer in tropical areas than in subtropical areas. Our results imply that the wood-boring longhorn beetles show higher degrees of niche conservatism and host-specificity in tropical forests than in subtropical forests. The high diversity of wood-boring longhorn beetles in tropical forests might be explained to a large extent by their more finely partitioned diet breadth.
... This has traditionally been used by foresters to project the yield of timber that could be extracted from the forest (Dawkins & Philip, 1998). Over time, forest ecologists have also used such plots to answer ecological questions such as on the diversity of tree species in forests and to gain insights into the forest dynamics, especially of forest structure, composition, and succession in terms of tree recruitment and mortality (Hubbell & Foster, 1992;Condit, 1995;Bakker et al., 1996). In the last few decades, global networks of permanent forest plots have also been established as observatories localities in 28 tropical and temperate countries, including the Bukit Timah Nature Reserve in Singapore where two 2-ha permanent plots have been established (Chua et al., 2013;Davies et al., 2021). ...
We review the history of plot-based studies of forests in Singapore and their contribution to our understanding of tropical forest ecology, especially of the regenerative capabilities of forest remnants after fragmentation, land-use change, and other disturbances. With this, we describe the establishment of the Long-Term Forest Ecological Monitoring plot network that includes the continued utilisation of sets of recently established, standardised plots along with the re-establishment of a historical set of plots surveyed by a team led by Wong Yew Kwan in 1992, ensuring the plot design is harmonised across the network.
... The BDGS plot was established in 2011 following the standards of the Center for Tropical Forest Science (Condit 1995). The first census was completed in 2011 and over 180,000 free-standing individuals with diameter at breast height (DBH) ≥ 1cm belonging to 232 species, 114 genera, and 53 families were tagged, measured, identified, and mapped. ...
It is well known that evergreen and deciduous species have different functional traits and utilize different strategies in growth and adaptation to environments, however little work has been done to elucidate whether leaf habit mediate the effect of trait-environment interactions on plant performance. Here we wanted to illuminate whether relative growth rate of deciduous and evergreen species depended on multiple trait-environment interactions. We measured eight leaf traits of 1230 individuals from 25 species and collected topographic factors, edaphic variables and competition index in a subtropic evergreen and deciduous mixed forest. Then we modeled plant relative growth rate with high-order trait-environment interactions for evergreen and deciduous species respectively using generalized linear mixed model and visualized the difference between leaf habits. Results showed that leaf habits were divided by trait PC1 (41.8%) which was related to leaf lifespan and resource acquisition. We found that trait-environment interactions improved growth predictions for both leaf habits but the optimal models for them were different. Moreover, the explanatory power of deciduous species models was always higher than that of evergreens. These results indicated that leaf habits with different life history strategies were reflected by trait-environment interactions. We emphasized the importance of leaf habits in explaining forest productivity and functions, and future research should focus on the effects of leaf habits on other demographic metrics and spatial patterns to solve the coexistence of the two leaf habits in mixed forests.
... The Wanang Forest Dynamics Plot (hereinafter WFDP, Fig. 1) is part of the global ForestGEO network of forest research sites (https://fore stgeo.si.edu/) dedicated to the study of tropical and temperate forest function and diversity. The research plot was established in 2009 in a lowland rainforest in the Middle Ramu region of Madang Province in Papua New Guinea at 5.24 • S and 145.08 • E (Anderson- Teixeira et al., 2015;Vincent et al., 2015) according to the so-called Condit's (1995) protocol. ...
... DOI: 10.17521/cjpe.2022 森林是陆地生态系统的主体, 占全球无冰区陆 地面积的44%以上 (Potapov et al., 2017), 为全球约 50%的已知物种提供生存环境, 是维持全球生物多 样性最重要的生态系统之一 (Davies et al., 2021)。永 久性大型森林动态监测样地是监测森林群落组成和 结构的重要研究平台, 具有传统小样方无法替代的 数据优势, 已成为研究生物多样性形成和维持机制 等重要生态学问题的有效手段 (Condit, 1995;马克 平, 2017;Davies et al., 2021) (Hubbell & Foster, 1986)。使用Ripley's G-Function的单种点格局分析方法 (Stoyan & Stoyan, 1994), 采用完全空间随机模型作为零模型, 分析样 地内重要值占比>5%的5个优势种的空间分布格局。 (Binder et al., 1993) (Baddeley et al., 2015 系统服务 (Janzen, 1970;Holt et al., 1994) ...
川西亚高山暗针叶林是中国寒温性针叶林的重要代表。以云杉(Picea spp.)和冷杉(Abies spp.)为优势树种的暗针叶林是青藏高原东缘亚高山森林的主体, 也是我国长江上游重要的生态屏障。该研究基于川西王朗保护区亚高山暗针叶林25.2 hm2动态监测样地的首轮清查数据, 分析样地木本植物组成和群落结构特征。依照全球森林观测网络(ForestGEO)的标准技术规范, 建立面积为25.2 hm2 (700 m × 360 m)的暗针叶林固定监测样地, 对胸径≥1 cm的木本植物进行挂牌标记、坐标定位、物种鉴定和检尺。主要结果有: 样地内共标记独立的木本植物个体56 574株, 分属15科27属46种, 其中针叶树4种, 常绿阔叶树6种, 落叶阔叶树36种; 每hm2个体数≤1的稀有种共13个, 占样地物种总数的28.26%, 占样地总个体数的0.16%。该群落以针叶树岷江冷杉(A. fargesii var. faxoniana, n = 9 440)和紫果云杉(P. purpurea, n = 1 645)为建群种和乔木层优势种, 重要值分别占总数的26.03%和10.69%, 其单位面积内的胸高断面积分别占总胸高断面积(37.87 m2·hm-2)的55.22%和24.84%。落叶阔叶树个体数占比最多(78.48%), 其中紫萼山梅花(Philadelphus purpurascens)、红脉忍冬(Lonicera nervosa)、冷地卫矛(Euonymus frigidus)为灌木层主要优势种。常绿阔叶树个体仅268株, 均为杜鹃属(Rhododendron)植物。木本植物的径级组成具有典型老龄林特征。单株最大胸径出现在紫果云杉, 达到127.07 cm。紫果云杉平均单株胸高断面积(0.14 ± 0.18) m2显著高于岷江冷杉(0.056 ± 0.11) m2。所有标记个体的径级分布呈倒“J”形, 表明群落处于稳定和正常生长状态。点格局分析的结果表明5个优势种(重要值占比>5%)均呈聚集分布, 但随着空间尺度的增加, 物种聚集程度变小, 趋向于随机分布。该研究的结果为深入研究川西亚高山暗针叶林的多样性维持与更新机制和该类型森林生态系统的保护与管理提供了基础信息。
... Long-term monitoring of vegetation plots is one of the largest investments in ecology and evolution (Condit, 1995;Davies et al., 2021). These plots have opened up research directions in community ecology and biodiversity that had previously been impossible, from tree community ecology to carbon sequestration and climate change (Anderson- Teixeira et al., 2021;Baker et al., 2017;Cuni-Sanchez et al., 2021;Goldstein et al., 2020;Mirtl et al., 2018;Sullivan et al., 2020;Zhong et al., 2021). ...
Long-term vegetation plots represent one of the largest types of research investments in ecology, but efforts to interrelate data on plants with that on animals is constrained because of the disturbance produced by human observers. Recent advances in the automated identification of animal sounds on large datasets of autonomously collected audio recordings holds the potential to describe plant-animal interactions, such as between frugivorous birds and fruiting trees, without such disturbance. We deployed an array of nine autonomous recording units (ARUs) on the 400 x 500 m Bubeng Forest Dynamics Plot, in Xishuangbanna, southwest China, and collected a total of 1965 hours of recordings across two seasons. Animal Sound Identifier (ASI) software was used to detect the vocalizations of five frugivorous bird species, and the probability of detection was related to the number of mature fruiting trees within a 50 m radius of the ARUs. There were more significant positive relationships than would be expected by chance in analyses that investigated bird/tree interactions across three months, both in the wet season and the dry season, as well as in short-term analyses within the dry season months of October and November. The analysis identified 54 interactions between bird and tree species with significant positive relationships. Follow-up observations of birds on the plot validated that such interactions were more likely to be observed than other interactions. We demonstrate that ARUs and automated voice identification can map the distribution and/or movement of vocal animals across large vegetation plots, allowing this data on animals to be inter-related to that on plants. We suggest that ARUs be added to the standardized protocols of the plot network, leveraging their vast amount of information about vegetation to describe plant-animal interactions currently, and monitor changes in the future.
... Intensive studies of species composition, forest structure, and dynamics have been conducted in lowland forests since the 1980s using large-scale research plots (Condit, 1995). Large-scale research plots are not only suitable for studying the distribution patterns of existing trees, but also tree regeneration, which is often expressed in terms of stem-size distributions (Bunyavejchewin et al., 2001;Kanzaki et al., 2004;Yamada et al., 1997). ...
Plant diversity is important for sustainable development, particularly in watershed areas. This study explored tree population and diversity in a lower montane forest (LMF). A 16-ha permanent plot was established in LMF at Huai Kogma sub-watershed, northern Thailand. All trees with a diameter at breast height ≥ 2 cm were tagged, measured, identified, and their coordinates were mapped. The results showed that 220 species in 139 genera from 63 plant families were found. The dominant families based on species numbers and tree density were Fagaceae, Lauraceae, and Theaceae. The most dominant species were Castanopsis acuminatissima, Schima wallichii, Castanopsis armata, and Styrax benzoides. Diameter classes for climax species frequently followed negative exponential distributions, indicating their populations could be maintained into the future. By contrast, pioneer species, such as Macaranga indica, Morus macroura, and Rhus javanica, had discontinuous distribution, and were mostly found in gap areas, indicating successful regeneration may require high light intensity. Spatial distribution patterns based on Morisita's index showed that most of the selected species had clumped patterns, particularly those in the Fagaceae family, which were predominantly distributed along the mountain ridge. Tree distribution patterns can affect ecological dynamics, thus reinforcing patterns dependent on local interactions such as the abundance of and distance to available resources. Our finding can aid evaluations of forest sustainability, and support the biodiversity conservation plans. In particular, the selection of suitable species for LMF restoration programs where mixed plantings of pioneer and climax species are planned.
... To evaluate how tree losses vary across the landscape, we generated a regular grid of 50-ha hexagonal cells overlaying the entire concession areas (Supplementary material Fig. S5) and estimated the percentage of basal area loss for each dispersal mode within each cell. We use a 50 ha cell size as this is the standard large tree plot size in tropical forest studies (Condit, 1995;Garzon-Lopez et al., 2014). All analyses were conducted in R version 3.6.3 ...
Fruits and seeds are key food resources for most Amazonian mammals and birds. Selective logging is an increasingly dominant land use in the region that can deplete these resources over large areas. However, this potential impact remains poorly studied. Here we assess potential losses of animal-dispersed (endozoochorous and synzoochorous) trees resulting from reduced-impact logging in Amazonian forest concessions. We use data from forestry surveys conducted by concession companies that include the location, identity and fate (logged or not) of large (≥ 40 cm diameter at breast height) individual trees within concessions to quantify absolute and relative losses of animal-dispersed trees in the landscape. We found that most individual trees (66%) within concessions belong to animal-dispersed genera. However, despite their predominance these trees were significantly less targeted for logging than abiotically-dispersed trees so that their losses were much lower than expected based on overall harvest intensities. However, at least ten percent of all large animal-dispersed trees were lost from the entire landscape, with site-level (50-ha plots) losses sometimes exceeding one third of all animal-dispersed trees. Results suggest that the relatively low level of logging for animal-dispersed trees can still deplete frugivore resources in selectively logged forests.
... To monitor the changes of vegetation composition, structure and function of C. lanceolata plantation, three 1 hm 2 C. lanceolata plantation monitoring plots (GS-1, GS − 2 and GS-3) were established in Guanshan, according to the CTFS (Centre for Tropical Forest Science) sample plot survey method of 2014 (Condit, 1995). From 1954 to 1956, seedlings of C. lanceolata were planted as follows: 5000 seedlings of C. lanceolata were planted at 2.5 m intervals; saplings were nurtured continuously for 10 years (including fertilizer application, weed removal, pest control and other tending measures). ...
The aim of this study was to understand the encroachment order, spatial patterns, interspecific associations, and species diversity of a Cunninghamia lanceolata plantation and to provide context for how to improve the spatial structure of C. lanceolata plantations. We investigated a Guanshan (C. lanceolata) Plantation in the Jiangxi Province. The C. lanceolata plantation was divided into three developmental stages (early, middle and late), with a space-for-time substitution method, according to their diameter at breast height (DBH) measurements. Across these plots, we analyzed encroachment patterns of the species and their interspecific associations with C. lanceolata according to the coordinates of trees in the plot, as well as the variation of species diversity after the encroachment of broad-leaf tree species. Our results show that the encroachment of broad-leaf trees into the C. lanceolata plantation followed a clear successional sequence of tree community assembly: intolerant tree species encroachment first, such as Alniphyllum fortunei and Liquidambar formosana, encroached; neutral tree species then encroachment, such as Daphniphyllum oldhamii and Schima superba, and shade-tolerant tree species encroachment last, such as Castanopsis eyrei and Castanopsis tibetana. Further, the spatial pattern of species establishment differed based upon when they encroached on the plantation. Intolerant and neutral tree species of early and middle developmental stages were distributed randomly. However, intolerant and some shade-tolerant tree species of the late developmental stage were aggregated on a scale of about 0–3 m. In addition, the interspecific associations between broad-leaf species encroachment into the C. lanceolata plantation were mainly negative, among which the most competitive ones were A. fortunei, D. oldhamii and Machilus thunbergii. However, with the development of the community, some species with negative correlations changed to having no correlation with C. lanceolata. We found that species diversity in the plantation gradually increased by nearly-five times from the early to the late developmental stage. Based on our collective results, we conclude that the encroachment and assembly of tree species show obvious order and pattern, which has a strong competitive effect with C. lanceolata in the naturalized plantation. Additionally, the community biodiversity has been significantly improved. Therefore, this successional process is important in the transformation of the C lanceolata plantation and different tree species should be replanted according to C. lanceolata plantation developmental stages with priority given to competitive species, such as A. fortunei, D. oldhamii, and M. thunbergii, so as to promote the C. lanceolata plantation change to C. lanceolata and broadleaf mixed forest.
... Forest ecosystems represent a critical buffer against anthropogenic climate change and we therefore must develop a deep understanding of their dynamics. An important tool in this endeavor is the stem-mapped forest stand; an area of forest where the size, species identity and precise location of each tree meeting a minimum size threshold are recorded (Condit 1995). Once established, these stands are revisited periodically to document mortality, re-measure trees and record any additional trees that newly meet the minimum size threshold. ...
Stem‐mapped forest stands offer important opportunities for investigating the fine‐scale spatial processes occurring in forest ecosystems. These stands are areas of the forest where the precise locations and repeated size measurements of each tree are recorded, thereby enabling the calculation of spatially‐explicit metrics of individual growth rates and of the entire tree community. The most common use of these datasets is to investigate the drivers of variation in forest processes by modeling tree growth rate or mortality as a function of these neighborhood metrics. However, neighborhood metrics could also serve as important covariates of many other spatially variable forest processes, including seedling recruitment, herbivory and soil microbial community composition. Widespread use of stem‐mapped forest stand datasets is currently hampered by the lack of standardized, efficient and easy‐to‐use tools to calculate tree dynamics (e.g. growth, mortality) and the neighborhood metrics that impact them. We present the forestexplorR package that facilitates the munging, exploration, visualization and analysis of stem‐mapped forest stands. By providing flexible, user‐friendly functions that calculate neighborhood metrics and implement a recently‐developed rapid‐fitting tree growth and mortality model, forestexplorR broadens the accessibility of stem‐mapped forest stand data. We demonstrate the functionality of forestexplorR by using it to investigate how the species identity of neighboring trees influences the growth rates of three common tree species in Mt Rainier National Park, WA, USA. forestexplorR is designed to facilitate researchers to incorporate spatially‐explicit descriptions of tree communities in their studies and we expect this increased diversity of contributors to develop exciting new ways of using stem‐mapped forest stand data.
... We then surveyed the woody plants in each plot by measuring the abundance of each plant species (or morpho-species) ≥ 5.0 cm diameter at breast height (1.2 m). All sampling methods used in the present study comply with the Center for Tropical Forest Science (http://www.ctfs.si.edu/) instructions for the assembly of long-term, large-scale forest data from the tropics 35 and with the Chinese Forest Biodiversity Monitoring Network (http://www.cfbiodiv.org/). Voucher specimens were collected whenever necessary in the eld for later identi cation with the help of plant taxonomists. ...
A long-debated question in ecology is whether the hyper-diversity of tropical plant-feeding insects is a direct consequence of high tropical plant diversity or should be attributed to increases in host plant specialization. In this study, we used Cerambycidae (the wood-boring longhorn beetles whose larval stages feed on the xylems of trees and lianas) and plants as study materials to explore which hypothesis is more favoured. Multiple analyses were used to show the differences in host specificity of Cerambycidae in tropical and subtropical forests. From these analyses, we found that the alpha diversity of beetles in tropical forests was significantly higher than that in subtropical forests, but not in plants. And the relationship of plants and beetles is closer in the tropical areas compared with subtropical areas. Our results imply that the wood-boring longhorn beetles show higher degrees of niche conservatism and host-specificity in tropical forests than in subtropical forests. The high diversity of wood-boring longhorn beetles in tropical forests might be explained to a large extent by their more finely partitioned diet-breadth.
... Future work within dry tropical forests should pursue research at large spatial and temporal scales in addition to small scales, following the large long-term forest plots that have been established in each of the major tropical rain forest formations of the world (Condit, 1995), and by taking advantage of the remote sensing techniques available for large-scale forest mapping in order to better understand dry tropical forest processes (Clark et aI., 2004;He et aI., 1998;Tickle et aI., 2006;Valerie & Marie-Pierre, 2006). This research has advanced the understanding of how highly similar congeneric species from the genus Bursera may coexist within this dry tropical forest. ...
p>In this research project, a variety of complimentary techniques have been used to investigate the potential mechanisms that may be maintaining the coexistence of five highly similar interdigitated species from the genus Bursera , within the seasonally dry tropical forest of Chamela, Jalisco, Mexico. The population dynamics, incidences of herbivore damage, plant chemistry, spatial patterns and microhabitat associations of the congeneric species Bursera instabilis, B. arborea, B. fagaroides, B. excelsa, and B. heteresthes were investigated.
Several coexistence theories were supported by evidence gathered during this research, where the predictions of those theories were explained by population processes determined by a seed size-seed number trade-off. The theories of patch dynamics, density- and distance-dependent mortality and dispersal limitation were suggested to interact within the larger framework of differential sensitivity storage dynamics. The differential sensitivity storage theory states that the coexistence of common and rare competing species is maintained by differential sensitivity to temporally varying environmental conditions, which results in fluctuations in seedling mortality and thus adult recruitment through time. Trade-offs between growth rate/performance and tolerance to herbivory/shade were suggested to explain the differential sensitivity of species within the genus Bursera . Temporal fluctuations in rainfall, which in turn influences canopy development and thus light conditions at the forest floor, in addition to herbivore pressure were then suggested to be potential environmental drivers of differential sensitivity storage dynamics.</p
... Each plot was divided into 25 quadrates (20 m × 20 m). All woody plant stems ≥ 1 cm diameter at breast height (DBH) in the plot were tagged, measured, and mapped [34], including DBH, coordinates, status and specimen collection, etc. The plots were established and data were collected following the plot standards of the Center for Tropical Forest Science network [35]. ...
Many areas are affected by the monsoon because of different sea and land positions. At the same time, the blocking effect of a mountain range forms different habitats on both sides of the mountain range. However, the distribution mechanism of woody plants is unclear in mountain forest ecosystems influenced by topography and monsoons. In this study, 10 plots, each with an area of 1 hm² (100 m × 100 m), were randomly established on the south and north aspects of a mountain forest. We examined community structure differences and distribution preferences of woody plants on both sides of the mountain. Our findings were as follows: (1) The characteristics of woody plant assemblages differed among various aspects. (2) Network analysis showed that specialization index was 0.186 and modularity index was 0.235, and the torus translation test showed that a total of 45 species were detected to be associated with at least one of the habitats (45/106, 42.45%). (3) The community stability of the south aspect was higher than that of the north aspect. Our findings suggest that the distribution of woody plants among different aspects was specialized and not random in alpine forest ecosystems. This study contributes to a clear understanding of the distribution mechanism of woody plants in mountain forest ecosystems influenced by topography and monsoons.
... Based on the technical specification for plot construction and monitoring of the Tropical Forestry Research Center of the Smithsonian Institution (Condit, 1995;Richard, 1998), 1 hm 2 sample plots(100 m × 100 m) were set in four kinds of sample forests, respectively. Each 100 m × 100 m plot was further divided into twenty-five 20 m × 20 m quadrats. ...
Soil microbes play a crucial role in a forest ecosystem. However, whether the distribution of bacteria and fungi in different forest succession stages is random or following ecological specialization remains to be further studied. In the present study, we characterized soil bacterial and fungal communities to determine their distribution preference, with different succession communities in a temperate mountain forest. The Kruskal–Wallis method was used to analyze structural differences between bacterial and fungal communities in different succession processes. The specificity of soil microbial distribution in a secondary forest was studied by network analysis. The torus-translation test was used to analyze the species distribution preference of soil microbes in different succession stages. Results showed that the species composition of soil bacteria and fungi differed significantly in different succession processes. The modularity index of fungi (0.227) was higher than that of bacteria (0.080). Fungi (54.47%) had specific preferences than bacteria (49.95%) with regard to forests in different succession stages. Our work suggests that the distribution pattern of most soil microbes in a temperate mountain forest was not random but specialized in temperate mountain forests. Different microbes showed different distribution preferences. Fungi were more sensitive than bacteria during secondary succession in a temperate mountain forest. In addition, microbe–environment relations varied during secondary succession. Our results provided new insight into the mechanism through which complex soil microbial communities responded to changes in forest community succession.
... According to the construction standards of the Smithsonian Institution's Center for Tropical Forestry Research [28], a 5-hectare plot (250 m × 200 m, horizontal distance) was established in the Baiyunshan National Nature Reserve. The 5-hectare plot was divided into 125 quadrats (400 m 2 each). ...
The temporal partitioning hypothesis refers to the promotion of stable species’ coexistence by reducing the likelihood of competitive exclusion, such as when species are active at different months of the year. However, the studies confirming the mechanisms of species’ coexistence focus on spatial scale, and temporal partitioning hypothesis for species’ coexistence remains underexplored. Fungal sporophores that are sensitive to seasonality change are ideal candidates for studying the role of temporal differentiation hypothesis in species’ coexistence. In this study, a field survey of fungal sporocarps was conducted from May to October, and the entity and abundance of different species of fungal sporocarps in a 5-hectare forest dynamic plot in a temperate, deciduous broad-leaved forest were recorded. The results showed that the emergence of fungal sporocarps based on month was highly specialized and uneven. The torus-translation test showed that 56 species exhibited ecological habitat preferences for different months (47/100, 47%). The distribution of soil fungal sporocarps (35/75, 46.67%) based on months showed higher specialization compared with that of rotten-wood fungal sporocarps (9/22, 40.90%). The findings suggest the importance of temporal partitioning in maintaining local diversity in the fungal community.
... Four 1 hm 2 plots were divided into 100 grids (10 m × 10 m). All trees with diameter at breast height (DBH) ≥1 cm in the plot were tagged, mapped, and measured [51]. Topographic variables (elevation, convexity, slope, and aspect) were measured using the methodology of Harms [52] for each 10 m × 10 m grid in the plot. ...
The mechanisms responsible for biodiversity formation and maintenance are central themes in biodiversity conservation. However, the relationships between community assembly, phylogeny, and functional traits remain poorly understood, especially following disturbance. In this study, we examined forest community assembly mechanisms in different disturbance regimes across spatial scales and including tree life history classes, using phylogenetic and functional trait metrics. Across disturbance regimes, phylogenetic structure tended to be over-dispersed, while functional structure tended to be clustered. The over-dispersion of phylogenetic structure also increased from small to large diameter species. Moreover, the explanation of spatial distance for the turnover of phylogenetic and functional structure was increased, while environmental distance explained less structure as disturbance intensity decreased. Our findings suggest that niche theory largely explains forest community assembly in different disturbance regimes. Furthermore, environmental filtering plays a major role in moderate to high disturbance regimes, while competitive exclusion is more important in undisturbed and slightly disturbed ecosystems.
... Species are the basic units of a community that occurs together in space and time [1]. A species may change its relative abundance, immigrate, or go extinct locally [2][3][4][5]. Species community dynamics may be influenced by both exogenous forces such as climate and endogenous ecological forces [2,5]. How multiple species have survived under different environments through time can provide information about their potential for facing various environmental conditions in the future [5,6]. ...
Monitoring long-term forest dynamics can improve our understanding of how tree species change under varying environmental conditions over time. The Nanjenshan Nature Reserve, located in the southernmost part of Taiwan, is covered by natural tropical forest and affected by the northeast monsoon wind in the winter. To explore how monsoon wind shapes the structure of vegetation, we used the long-term data of the Lanjenchi plot (high wind exposure forest) and Nanjenshan plot I (low wind exposure forest) located in the Nanjenshan Nature Reserve. In these two plots, all free-standing trees with diameter at breast height (DBH) ≥ 1 cm were identified, measured, and mapped five times in thirty years (1989–2019). Temporal changes of tree abundance, dominance, recruitment, and mortality were calculated for all species. We recorded 9694 ± 3924 individual ha−1 belonging to 126 species in the high wind exposure forest and 4019 ± 1791 individual ha−1 belonging to 105 species in the low wind exposure forest in the latest census (census 5). From 1989 to 2019, stem density in the high wind exposure forests decreased (from 12,179 ± 6689 to 9694 ± 3924 individual ha−1), while stem density in the low wind exposure forests increased (from 3253 ± 1208 to 4019 ± 1791 individual ha−1). The stem density of the rare species, which survived only in the high wind exposure forest, decreased over time. However, the basal areas of these two forests barely changed during the study periods. Due to environmental conditions, the two forests have developed different forest structures in spaces and time. Species stem density in the high wind exposure forest and diversity could continually decrease and affect the maintenance of species diversity in the monsoon wind-shaped forest.
Forest degradation of the Himalayan ecosystem has become an issue of concern, and the increasing human-induced activities are responsible for it. The management and conservation of endemic species in the IHR can play a significant role in forest restoration works and simultaneously help sequester carbon, which is essential to mitigate climate change. Therefore, the present study aims to determine the long-term structural and functional behavior of the endemic species through long-term monitoring of permanent plots in Shimla Water Catchment Wildlife Sanctuary and Shikari Devi Wildlife Sanctuary across northwestern Himalayan using CTFS protocol. The results show that a total of 2,936 individuals over 1 cm dbh in Cedrus deodara forest stand at Shimla Water Catchment Wildlife Sanctuary, 953 individuals in the Abies pindrow dominant, and 1452 individuals in the pure Quercus semecarpifolia dominant were recorded in Shikari Devi Wildlife Sanctuary. The Cedrus deodara (2085 individuals) accounting for 71.0 % of the Relative abundance (RA) and (176.3) Important Value Index (IVI) in Shimla Water Catchment Wildlife Sanctuary. However, Abies pindrow (836 individuals) accounted for 87.7 % (RA) and (201.1) IVI in the first plot and Quercus semecarpifolia 1366 individuals, accounting for 94.08 % (RA) and 231.1 (IVI) in the second plot at Shikari Devi Wildlife Sanctuary, The above-ground biomass (AGB) of Abies pindrow dominant forest stand contributed a more significant amount of biomass 479Mgha⁻¹ and carbon stock 239Mg ha⁻¹, followed by the Cedrus deodara, 346.9 Mgha⁻¹ and 173.4 Mgha⁻¹, and Quercus semecarpifolia 334.10, Mg ha⁻¹ and 167.5 Mg ha⁻¹, respectively.
In this study, experiments were conducted on soil samples collected from depths of 0–15 cm, 15–30 cm, and 30–50 cm at the National Long-term Scientific Research Base for the Comprehensive Management of Rocky Desertification in the Wuling Mountains. The aim was to determine the physicochemical indexes and explore the nature and spatial heterogeneity of the soil of the planted mixed forests within the rocky desertification area of the Wuling Mountain. Various analytical methods were employed, including descriptive statistical analysis, correlation analysis, analysis of variance, principal component analysis, spatial interpolation analysis, and kriging interpolation, to fit the optimal model of the semi-variance function of soil physicochemical properties and analyze the model’s parameters. The results indicated that soil physical and chemical properties varied with depth and were generally correlated. The relationship between soil organic matter and total nitrogen content was the closest. Additionally, there was a certain degree of correlation between soils at different depths in the vertical profile, generally the correlation between layer B (15–30 cm) and layer C (30–50 cm) > that between layer A (0–15 cm) and layer B (15–30 cm) > that between layer A (0–15 cm) and layer C (30–50 cm). The weighting coefficients of the principal components of soil physicochemical properties indicated that soil organic matter, nitrogen, phosphorus, potassium, pH, total porosity, and capillary porosity are key factors in the soil properties of karst desertification areas. The spatial variability of soil physicochemical properties at different depths ranged from 21.91 to 87.59 m, and the abutment ratio (Co/Co+C) of these properties ranged from 12.99% to 89.53%. Using kriging interpolation in ArcGIS, the spatial distribution pattern of soil physical and chemical properties was mapped, revealing that these indicators were distributed with heterogeneous patches of various sizes and shapes. Therefore, the degree of rocky desertification significantly influences the spatial distribution pattern of soil physical and chemical properties.
Understanding the composition and structure of forest trees is crucial to comprehending the properties and functions of forests. It also helps in implementing effective management strategies for sustainable resource utilization. Our study analyzed the structural dynamics of the old-growth mixed oak forests in the Xiaolongshan Forest region, focusing on three long-term monitoring plots (A, B, C). We examined the tree species composition, diameter distribution, mortality, and recruitment dynamics of different successional species groups, as well as the spatial distribution patterns of living and dead trees, with surveys conducted every five years. The findings indicate: (1) Plot A experienced a decline in stand density and species diversity during the survey period, with the Importance Value Index (IVI) of pioneer successional species continually decreasing in plots B and C. (2) The tree diameter distribution structure in plot A significantly differed from other plots, showing notable change between 2007 and 2012. (3) All plots exhibited lower, well-balanced community-level demographic parameters based on stem number, but a higher recruitment rate for later successional species groups based on basal area. (4) Dead individuals in plot A had a slight clustering distribution, while the other plots showed a random distribution. We conclude that the individual growth rate significantly impacts the dynamics of the natural Quercus aliena var. acuteserrata forest, with pioneer species groups being gradually replaced by early or late-successional species groups in the succession process.
Se realizó una revisión sistemática de la literatura sobre la homogeneización biótica en bosques tropicales y sus consecuencias para la diversidad de las comunidades arbóreas. Evaluamos artículos indexados en las bases Scopus® y Web of Science®, desde 1945 hasta 2022. La selección de publicaciones se llevó a cabo en la plataforma Rayyan. El método bibliométrico utilizado para el mapeo de la base de datos fue el análisis de co-palabras, en el software VOSviewer. Identificamos tres líneas de investigación en homogeneización biótica: ecología de la invasión de especies; factores ambientales y antropogénicos; y diversidad funcional y filogenética. El componente más estudiado y posiblemente el más afectado fue el componente taxonómico. Los eventos de homogeneización biótica están ampliamente distribuidos en la región tropical, siendo el tipo de bosque más afectado el bosque tropical lluvioso, y la principal causa señalada fue el cambio en el uso del suelo, relacionado con la degradación antropogénica. Los estudios sobre homogeneización biótica en los trópicos se han intensificado en la última década y han resultado en avances importantes para comprender este proceso, como la constatación de que los ambientes hiperdiversos son susceptibles a la ocurrencia de homogeneización biótica y que esta puede estar mediada por especies nativas generalistas. Observamos la aparición de otro componente de la diversidad que debe incluirse en el concepto de homogeneización: la homogeneización de las interacciones ecológicas.
Uma revisão sistemática de literatura foi realizada sobre a homogeneização biótica em florestas tropicais e suas consequências para a diversidade das comunidades arbóreas. Avaliamos artigos indexados nas bases Scopus® e Web of Science®, de 1945 a 2022. A seleção das publicações foi realizada na plataforma Rayyan. O método bibliométrico utilizado para o mapeamento do banco de dados foi a análise de co-palavras, no software VOSviewer. Distinguimos três linhas de pesquisas em homogeneização biótica: ecologia da invasão de espécies; fatores ambientais e antropogênicos; e a diversidade funcional e filogenética. O componente mais estudado e talvez o mais afetado, foi o componente taxonômico. Os eventos de homogeneização biótica estão amplamente distribuídos pela região tropical, sendo o tipo florestal mais afetado a floresta tropical pluvial e a principal causa apontada foi a mudança de uso do solo, relacionada à degradação antrópica. Os estudos de homogeneização biótica nos trópicos têm se intensificado na última década e resultado em importantes avanços para o entendimento deste processo, como a constatação de que ambientes hiperdiversos são suscetíveis de ocorrência de homogeneização biótica e que ela pode ser mediada por espécies nativas generalistas. Observamos o surgimento de mais um componente da diversidade a ser incluído no conceito da homogeneização, a homogeneização das interações ecológicas.
Ferns are an integral part of the world's flora, appreciated for their beauty as ornamentals, problematic as invaders and endangered by human interference. They often dominate forest understories but also colonize open areas, invade waterways and survive in nutrient-poor wastelands and eroded pastures. Presented here is the first comprehensive summary of fern ecology, with worldwide examples from Siberia to the islands of Hawaii. Topics include a brief history of the ecological study of ferns, a global survey of fern biogeography, fern population dynamics, the role of ferns in ecosystem nutrient cycles, their adaptations to xeric environments and future directions in fern ecology. Fully illustrated concepts and processes provide a framework for future research and utilization of ferns for graduate students and professionals in ecology, conservation and land management.
TÓM TẮT
Using Sentinel 2 data on Google Earth Engine cloud computing
platform for assesssing forest cover change in special use and
protection forests in Vo Nhai district, Thai Nguyen province
Changing in forest cover leads to a reduction of forest area in a spcecific time
period. The research applied Google Earth Engine (GEE) to develop forest
cover map layers and acccuracy assessment of classified forest cover maps
for Sentinel 2. The study was conducted in special use forest areas in
Specieal use and Protection Forest Management Board of Thai Nguyen
province (former was Than Sa - Phuong Hoang nature reserve Management
Board). Random Forest (RF) was applied in this study for classification and it
performed a high acccuracy of classified images for forest covers. The results
showed that the classification accuracy of classified maps in 2017, 2018,
2019, 2020 and 2021 was 98.7%; 99.3%; 99.3%; 98.5% và 99.5% (Overall
acccuracy) and 0.974; 0.985; 0.986; 0.969 và 0.990 (Kappa) respectively.
There was a significant upward trend of forest cover in the period from 2017
to 2021. Specifically, forested areas rose by 894,5 ha in the period from 2017
to 2021. The drivers of forest cover increase were due to afforestation and
forest restoration. Implication of GEE, Sentinel 2 and classification algorithm
RF achieved a high accuracy of the forest cover classification and it could be
able to apply for other regions in Thai Nguyen province.
MANOKARAN, N. & LaFRANKIE, J.V. 1990. Stand structure of Pasoh Forest Reserve, a lowland rain forest in Peninsular Malaysia. We tabulate and analyse the stand structure of Pasoh Forest Reserve, Malaysia, based on an enumeration of all trees > 1 cm dbh in a 50-ha plot. Mean densities were 6769 trees ha 1 , > 1 ondbh, 530 trees ha 1 , > 10 cm dbh, 3.0 trees ha 1 , > 90 cm dbh. Mean basal area was 30.5 m 2 ha 1 for all trees, and 25.2 m2 ha 1 for trees > 10 cm dbh. Ground slope had a very weak negative correlation with density of small trees (<10 cm dbh) and a very weak positive correlation with density of large trees (>30 cm dbh). Compared with other primary forests in Malaysia, Pasoh was relatively dense in smaller trees and relatively sparse in very large trees. The forest within the 50-ha plot was generally homogeneous, with no evidence of major disturbance, and it is likely representative of mean conditions of lowland forest in south-central Malay Peninsula.
A high number of tree species, low density of adults of each species, and long distances between conspecific adults are characteristic of many low-land tropical forest habitats. I propose that these three traits, in large part, are the result of the action of predators on seeds and seedlings. A model is presented that allows detailed examination of the effect of different predators, dispersal agents, seed-crop sizes, etc. on these three traits. In short, any event that increases the efficiency of the predators at eating seeds and seedlings of a given tree species may lead to a reduction in population density of the adults of that species and/or to increased distance between new adults and their parents. Either event will lead to more space in the habitat for other species of trees, and therefore higher total number of tree species, provided seed sources are available over evolutionary time. As one moves from the wet lowland tropics to the dry tropics or temperate zones, the seed and seedling predators in a habitat are hypothesized to be progressively less efficient at keeping one or a few tree species from monopolizing the habitat through competitive superiority. This lowered efficiency of the predators is brought about by the increased severity and unpredictability of the physical environment, which in turn leads to regular or erratic escape of large seed or seedling cohorts from the predators.
An inventory was made of 50 ha of primary lowland rain forest in Peninsular Malaysia, in which ca. 340,000 trees 1 cm dbh
or larger were measured and identified to species. Out of a total plot tree flora of 820 species, 76 species are known to
bear edible fruit. Especially diverse were the wild species of mango (Mangifera, Anacardiaceae, 12 spp.), mangosteen (Garcinia,
Clusiaceae, 13 spp.), breadfruit (Artocarpus, Moraceae, 10 spp.) and rambutan (Nephelium, Sapindaceae, 5 spp.). Median population
size for all species of fruit trees was 3.0 trees per ha and 0.2 adult trees per ha. Direct economic value of wild fruit trees
was small; only one species has been very much collected and sold, Parkia speciosa (Fabaceae), amounting to less than US
20 per ha per year. The potential value of the species as genetic resources is very large: 24 species are cultivated, 38 edible species are congeneric with cultivated crops and at least 10 other species bear inedible fruit but are related to cultivated crops. We conclude that the Peninsular Malaysian rain forest is exceedingly rich in wild fruit trees, that these normally live at low densities, and that their principal economic value is as genetic resources. < /div > < div class=bstract < a name=bs2 < /a > de tierra baja primaria de selva lluviosa de Malasia Peninsular, en el cual se medió y se identificó la especie de aproximadamente unos 340,000 árboles de 1 cm de diametro (a la altura del pecho) o mayores. De un total de un terreno de flora de árboles de 820 especies, se sabe que 76 especies dan frutos comestibles. Resultaron ser particularmente variades las especies silvestres de mango ( < i > Mangifera < /i > , Anacardiaceae, 12 spp.),
By drawing on quantitative studies in social anthropology, zoology, ethnobotany, and economics we present a method for conducting
an economic valuation of non-timber forest products. A review of 24 studies suggests that the median value for non-timber
forest products is about $50/ha/year. We discuss problems with past studies and suggest ways to get better estimates of output
quantities, marginal costs, and prices.
Patterns of tree abundance and dispersion in a tropical deciduous (dry) forest are summarized. The generalization that tropical trees have spaced adults did not hold. All species were either clumped or randomly dispersed, with rare species more clumped than common species. Breeding system was unrelated to species abundance or dispersion, but clumping was related to mode of seed dispersal. Juvenile densities decreased approximately exponentially away from adults. Rare species gave evidence of poor reproductive performance compared with their performance when common in nearby forests. Patterns of relative species abundance in the dry forest are compared with patterns in other forests, and are explained by a simple stochastic model based on random-walk immigration and extinction set in motion by periodic community disturbance.
Global changes in climate, atmospheric chemistry and land use are affecting the biological composition, productivity and sustainable use of terrestrial ecosystems. The need for improved and reliable information on the responses of natural and managed systems to global change is widely recognized. The data are required both to detect and monitor changes and to develop and test models for projection of future changes. Remote sensing can increasingly provide comprehensive information on changes in land cover and land use and on measurement of some surface features, such as temperature and chemical composition. This information needs to be complemented by more detailed ground-based measurements such as species composition and performance, and environmental processes. The Global Terrestrial Observing System (GTOS) will cooperate with organisations such as START to provide benefits in research, training, information and facilities within developing countries as well as providing an early warning system of responses to global change and providing data for global models. -from Publisher
The 1982-83 El Niño event afflicted Barro Colorado Island, in central Panama, with a dry season that began a month early. Although the drought ended “on schedule”, it was especially severe during the last 13 of its 24 weeks. It is considered the “worst” dry season since the start of Barro Colorado's rainfall records in 1929, and quite possibly the worst in 190 years. Tree mortality seems to have been 5 times higher than usual in 1983, and Barro Colorado's forest was visibly stressed, but its animal populations were little affected. The forest seemed to have recovered fully by 1984's rainy season. Damage to the forest was much less severe or lasting than that caused by a contemporaneous drought in east Borneo. Moreover, the El Niño drought did not initiate a progressive deterioration of Barro Colorado's forest community comparable to the progressing disaster unleashed by Hurrican Allen on the reefs of the north coast of Jamaica. The sharp dry season that strikes Barro Colorado every year seems to have “preadapted” its forest for surviving El Niño droughts without excessive damage, so long as they do not occur “out of season.”
(1) Quararibea asterolepis (Bombacaceae), a common canopy tree in the old forest on Barro Colorado Island, Panama, was the only species defoliated during an outbreak of Eulepidotis (Noctuidae) larvae in May and June 1985. (2) The level of defoliation among 460 potentially reproductive trees (⩾ 16 cm dbh) over a 50-ha plot was related to local conspecific density and to the severity of defoliation of the three nearest neighbours. (3) Young leaves suffered greater damage than mature leaves in the same Quararibea crown. Trees with mostly young leaves before the outbreak suffered heavier defoliation than those with mostly mature leaves. Trees that escaped defoliation had either all or mostly mature leaves. (4) When sapling pairs were matched with respect to leaf age, saplings near an infested adult suffered heavier defoliation than distant saplings. The distance effect was reversed, however, when near saplings had mature leaves and far saplings had young leaves. (5) Heavily defoliated crowns of large (⩾ 64 cm dbh) Quararibea trees produced significantly fewer flowers and fruits than lightly defoliated crowns. Flowering also occurred later and was less synchronized for heavily defoliated trees. This difference in reproductive output did not persist beyond the outbreak year.
Density dependence was examined in two species of neotropical treelets, Faramea occidentalis and Desmopsis panamensis, in a 50-ha plot on Barro Colorado Island in Panama. Survival and growth probability of plants larger than 1 cm dbh (diameter at breast height), and recruitment into the 1-cm class, were assessed as a function of the number of conspecific neighbors in various distance and size classes. Density-dependent effects on survival and growth were strong in Faramea. Performance of 1-8 cm dbh plants declined with increasing numbers of adult neighbors within 1 m, 1-2 m, and 2-4 m, but neighbors at 4-6 had no effect. Performance also declined with increasing numbers of juvenile neighbors <4f cm dbh, but the effect was less pronounced. Saplings of Faramea grew poorly in areas of high juvenile density within 30 m, independent of the effects caused by neighbors within 4 m. In contrast to Faramea, Desmopsis showed no density dependence in survival nor in growth. For recruitment, however, the two species showed similar patterns: recruit density was lower in regions with an adult conspecific within 1 or 2 m distance, but higher in regions with high densities of adult or juvenile conspecifics between 2 and 30-60 m. Desmopsis must have suffered density-dependent effects at stages <1 cm dbh, but the effect vanished by the 1 cm dbh stage. In Faramea, strong neighborhood effects were evident in all size classes <8 cm dbh.
Studied the survival, diameter growth, and recruitment of saplings in >100 species of woody plants in a 50-ha permanent plot of moist tropical forest on Barro Colorado Island, Panama, from 1982-1985. The performance of saplings in low-canopy sites (<10 m) was compared to that of saplings in high-canopy sites. Of the 108 species for which all 3 parameters of performance were measured, 104 fell into 4 response groups. Pioneers (6 species) survived poorly in both canopy-height categories, and survivors grew rapidly in low-canopy sites. Sapling recruitment was skewed toward low-canopy sites. Understory specialists (3 species) survived well in high-canopy sites and poorly in low-canopy sites. They grew slowly and recruited poorly in both situations. Generalists (79 species) survived well and grew slowly in both canopy-height categories. Per-adult recruitment was usually low, and often skewed toward low-canopy sites. Poorly deforming species (16 species) survived poorly, grew slowly, and recruited infrequently in both canopy-height categories. Rare and occasional species had significantly more recruits per adult than did common species, but often this did not balance their higher mortality. Large differences in survival, growth, and recruitment between canopy-height categories were found only among rare and occasional species. -from Authors
Sustainable management of natural tropical forests is not possible without a better holistic understanding of how such forests actually work ecologically and interact with humans. Because time is short, we must learn "on-the-job' by conducting research as we implement management plans. The authors base their argument on experience with a large-scale study of the tropical forest on Barro Colorado Island, Panama. In the space of 5 yr, it was possible to collect essential silvics data on stocking levels, growth, yield, survival rates, and microhabitat requirements of a large fraction of the tree community of >300 native species. A program of comparable studies of representative natural and managed tropical forests at key sites throughout the tropics would rapidly improve the global fund of knowledge on which to base better decisions for the conservation and management of tropical forests. -from Authors
We report dynamic data on the spatial pattern of sapling recruitment over a three-year interval in a 50 ha mapped plot Barro Colorado Island (BCI), Panama. We analysed sapling recruitment of a given tree species against recruitment of all other competing tree species, as a function of distance to nearest conspecific adult tree. Strong negative conspecific effects of large trees on saplings were detectable in a few very common species, but not in many others. The power to detect conspecific effects was evaluated in model tree populations in which the strength of these effects was known a priori. The measured conspecific effects appear strong enough in the densest species to prevent them from assuming complete dominance. However, many species do not show these effects, and we conclude that these effects play only a limited contributing role to the maintenance of tree species diversity in the BCI forest.
The demography of a valuable timber tree, Prioria copaifera, was studied in undisturbed forest on Barro Colorado Island (BCI) in central Panama using data from a permanent, 50 ha census plot. All individuals above 20 mm diameter at breast height (dbh) in the plot were mapped and dbh measures taken in 1982, 1985, and 1990. Although Prioria is mainly known from swamp forest, it was abundant in the upland forest of BCI, with a mean density of 27–29 stems ha−1 of 10 mm dbh or more. Mortality rates of Prioria were 0.5 and 0.6% year−1 during the two census intervals and did not depend on dbh. Mean growth of saplings was slow, less than 1 mm year−1, but larger trees grew rapidly, at 8–16 mm year−1. Growth rates of medium and large trees were higher during 1985–1990, probably because a severe drought in 1983 increased forest-wide mortality rates and opened the forest canopy, allowing more light to penetrate the forest. During both census intervals, growth was extremely variable, ranging from 0 to 40 mm year−1 in different individuals. The range of variability changed little with size: across dbh values from 100 to 1000 mm, maximum growth rates were 20–40 mm year−1. Unlike absolute growth rates, however, relative growth declined with size, from about 5% year−1 in saplings to 1% year−1 in large trees, and was much more variable among small stems than among larger.Information about variation in growth between individuals and between census periods will be important in forest management, as it indicates how and to what extent silvicultural treatment might enhance timber production in Prioria. In addition, rapid growth of some stems suggests that plantation forestry might be productive in Prioria. Our finding that population density and performance were good in upland soils suggests that plantations of this species could be attempted in drier soils than previously thought necessary.
A multilocus mixed mating model was used to analyze the mating systems of two tropical canopy trees in the Bombacaceae that differ in successional status and overall abundance. One population of each species was studied on Barro Colorado Island, Republic of Panama. Population outcrossing estimates of 0.57 and 0.35 from two years indicate a mixed-mating system with intermediate outcrossing levels for the gap-specialist Cavanillesia platanifolia, a relatively rare component of the island flora. Population and individual outcrossing estimates were associated with flowering tree density or degree of spatial isolation. Trees within clusters of flowering individuals have a higher degree of outcrossing than isolated trees. Annual estimates of individual tree outcrossing rates varied greatly as a function of flowering in its nearest neighbors. In contrast to C. platanifolia, Quararibea asterolepis was completely outcrossed and may be self incompatible. Maternal trees of both species had significantly heterogeneous pollen pools indicating non-random outcrossing. Apomixis by sporophytic agamospermy was rejected in C. platanifolia as contributing to the apparent selfing rate.
The population biology of Aquilaria malaccensis, one source of gharu, and Cinnamomum mollissimum, one source of wild cinnamon, was studied in a 50 ha permanent plot of primary rain forest in Malaysia. Median diameter growth rates of 0.22 cm yr-1 and 0.1 cm yr-1 should not be prohibitive of economic exploitation, and suggest that the trees could be grown commercially. However, the natural densities were between 2 and 3 trees over 1 cm d.b.h. per ha, which is roughly the median for all trees in the plot, would preclude economic exploitation of these natural populations. The economics of harvesting natural populations is considered in a preliminary fashion by allowing favorable assumptions of quantity and quality of production. The price likely to be fetched from either a first time extraction (on the order of US0.10 per ha per yr), are too small to be of interest as single-product schemes, and are negligible compared to the extraction of multi-species crops of timber. However, it is possible that by combining multiple products under a "High Diversity Forestry" scheme, one could increase the density of harvestable products, reduce the unit cost of labor and improve the economic portrait.
To screen for rapidly growing trees, lifetime growth histories of 160 species were estimated from data collected in a permanent 50 ha census plot in tropical moist forest in Panama. Most of the 160 species had never been studied before in detail, and newly encountered species with rapid growth might provide better techniques for reforesting degraded soils in Central America. To estimate lifetime growth, polynomial regressions were fitted to instantaneous growth rates expressed as a function of log-transformed diameter at breast height (dbh). These functions represent a differential equation in dbh, and explicit solutions for the equations provided dbh trajectories as a function of age (starting at 1 cm dbh, which was the smallest size included in the census). Dbh trajectories were calculated for 160 species, and full growth data are presented for the 28 species that ranked among the fastest 15 to reach a dbh of 10, 30, or 60 cm. Dbh trajectories based on growth of one standard deviation above the mean were also estimated for these species by fitting a polynomial regression to the residuals around the original regression. The fastest-growing tree in the 50 ha plot was the balsa, Ochroma pyramidale, which reached 10 cm in 5 years and 30 cm in 10. Cavanillesia platanifolia, Trema micrantha, Zanthoxylum belizense, and Vochysia ferruginea were the other top-ranking species. At mean growth, the top 15 ranking species required 5–25 years to reach 10 cm, 10–67 years to reach 30 cm, and 32–111 years to reach 60 cm, starting at 1 cm. At growth one standard deviation above the mean, the same species requried 4–18 years to reach 10 cm, 8–35 years to reach 30 cm, and 19–69 years to reach 60 cm dbh. We recommend that the little-known species from this list be further tested in reforestation trials.
According to ‘Gause's hypothesis’ a corollary of the process of evolution by natural selection is that in a community at equilibrium every species must occupy a different niche. Many botanists have found this idea improbable because they have ignored the processes of regeneration in plant communities.
Most plant communities are longer‐lived than their constituent individual plants. When an individual dies, it may or may not be replaced by an individual of the same species. It is this replacement stage which is all‐important to the argument presented.
Several mechanisms not involving regeneration also contribute to the maintenance of species‐richness:
differences in life‐form coupled with the inability of larger plants to exhaust or cut off all resources, also the development of dependence‐relationships,
differences in phenology coupled with tolerance of suppression,
fluctuations in the environment coupled with relatively small differences in competitive ability between many species,
the ability of certain species‐pairs to form stable mixtures because of a balance of intraspecific competition against interspecific competition,
the production of substances more toxic to the producer‐species than to the other species,
differences in the primary limiting mineral nutrients or pore‐sizes in the soil for neighbouring plants of different soecies, and
differences in the competitive abilities of species dependent on their physiological age coupled with the uneven‐age structure of many populations.
The mechanisms listed above do not go far to explain the indefinite persistence in mixture of the many species in the most species‐rich communities known.
In contrast there seem to be almost limitless possibilities for differences between species in their requirements for regeneration, i.e. the replacement of the individual plants of one generation by those of the next. This idea is illustrated for tree species and it is emphasized that foresters were the first by a wide margin to appreciate its importance.
The processes involved in the successful invasion of a gap by a given plant species and some characters of the gap that may be important are summarized in Table 2.
The definition of a plant's niche requires recognition of four components:
the habitat niche,
the life‐form niche,
the phenological niche, and
the regeneration niche.
A brief account is given of the patterns of regeneration in different kinds of plant community to provide a background for studies of differentiation in the regeneration niche.
All stages in the regeneration‐cycle are potentially important and examples of differentiation between species are given for each of the following stages:
Production of viable seed (including the sub‐stages of flowering, pollination and seed‐set),
dispersal, in space and time,
germination,
establishment, and
further development of the immature plant.
In the concluding discussion emphasis is placed on the following themes:
the kinds of work needed in future to prove or disprove that differentiation in the regeneration niche is the major explanation of the maintenance of species‐richness in plant communities,
the relation of the present thesis to published ideas on the origin of phenological spread,
the relevance of the present thesis to the discussion on the presence of continua in vegetation,
the co‐incidence of the present thesis and the emerging ideas of evolutionists about differentiation of angiosperm taxa, and
the importance of regeneration‐studies for conservation.
According to the Janzen-Connell hypothesis for the maintenance of species diversity, recruitment is inhibited in the immediate vicinity of adults by herbivores and pathogens. This reduces the per capita ability of abundant species to reproduce, relative to less common species, and gives rare or competitively inferior species a greater chance to persist. We tested this hypothesis in a 50-ha mapped plot of tropical moist forest on Barro Colorado Island, Panama, by investigating the spatial patterns of sapling recruitment in 80 species of trees and shrubs. Two censuses of adults and saplings were carried out, in 1982 and in 1985. Recruits were defined as saplings of 1-8 cm dbh (diameter breast height) appearing in the 1985 census that were not present in 1982. The distance from each recruit to its nearest conspecific adult neighbor was measured. At various distances from adults, the number of conspecific recruits and the number of recruits of all species were tallied. The ratio of recruits of species i to all recruits was taken as an estimate of the probability that species i would occupy that site as an adult. A few species showed a significant reduction in recruitment probability close to adults, but more species showed a significant increase, and many other species showed no significant spatial pattern. Among canopy trees, about a third of the species showed some sign of local reduction in recruitment, but the distance over which the effect extended was usually less than 5 m; however, the most abundant canopy tree, Trichilia tuberculata, showed a sharp reduction in recruitment probability up to 10 m from adults. In treelets and shrubs, most species showed strong peaks in recruitment probability close to adults. Thus, most recruitment patterns did not fit the prediction of Janzen and Connell; however, two to three of the most common species may have reached densities at which a depression in local recruitment is regulating abundance.