Spatial Patterns Of Species Richness Research Articles

Historical and contemporary climate jointly determine angiosperm plant diversity patterns across east Eurasia

Mechanisms underlying large‐scale spatial patterns of species richness are one of the central issues in ecology. Although contemporary climate, evolutionary history, and historical climate change have been proposed as drivers of species richness patterns, variation in the relative importance of different factors remains a major challenge. Here, using newly compiled distribution data with a spatial resolution of 100 × 100 km for 43 023 angiosperms plant species in east Eurasia, we mapped species richness patterns for plants with different growth forms (i.e. woody versus herbaceous) and range sizes (i.e. wide‐ranged versus narrow‐ranged species), and compared the relative importance of the four hypotheses in explaining these patterns, i.e. freezing tolerance hypothesis, historical climate change hypothesis, Janzen's hypothesis (predicting that climate seasonality and topography determine species richness patterns), and diversification rate hypothesis. We found that species richness of all angiosperm plants presented a clear latitudinal gradient and was highest in southwestern China and Central Asian mountains. Notably, species richness patterns and their dominant drivers differed between species groups. Historical climate change was the dominant driver for richness patterns of all and herbaceous species. The freezing tolerance hypothesis dominated the drivers for all woody species, while Janzen's hypothesis dominated narrow‐ranged woody and herbaceous species. Our study suggests that different hypotheses contribute to large‐scale plant richness patterns via their effects on different plant groups. Our results did not support the diversification rate hypothesis, but demonstrated the high importance of historical climate change to plant diversity in east Eurasia, providing new perspectives on the mechanisms of plant diversity patterns in this continent.

Elevational range size of the breeding bird assemblages and its relationships with richness in the Eastern Himalayas

Species range size reflects the underlying niche of species and directly affects the spatial pattern of species richness. However, the exploration of community mean range size has received relatively limited attention compared to the emphasis on species richness patterns. Additionally, few studies have tested how the rescue effect (the proximity of the distribution limits of potentially interacting species) relates to species richness. In this study, we used a two-year dataset of breeding birds along an elevational gradient in the Lebu Valley, Eastern Himalayas of China, aiming to explore (a) the association between the mean elevational range size of bird community and elevation, using three different ways to calculate the mean elevational range size (Stevens' method, midpoint method and specimen method), (b) examine the influence of drivers (including temperature seasonality, precipitation seasonality, net primary productivity, habitat diversity, geometric constraint, and interspecific competition) on the mean elevational range size pattern, and (c) investigate the effect of rescue effect on species richness pattern. Our results showed that the pattern of mean elevational range size and its underlying drivers vary significantly depending on the assessment method used. Using Stevens' method, which were calculated based on species occurrences, we observed a low-plateau pattern in mean elevational range size. In contrast, the midpoint and specimen methods, which calculate based on the species' distributing midpoint and abundance center, respectively, revealed a mid-peak pattern. Besides, our study supports several ecological hypotheses, including the ambient energy hypothesis, mid-domain hypothesis, and interspecific competition hypothesis. Furthermore, we found that geometric constraints and interspecific competition were the most influential predictors of mean elevational range size patterns, irrespective of the calculation method. Additionally, a significantly positive correlation was observed between the overlap of range margins and species richness, suggesting a contribution of the rescue effect to species richness patterns. The significance of the correlation is associated with the definition of species range size boundaries. Remarkably, this correlation becomes significant only when species range margins reach their 43 % threshold; beyond the 78 % range margin, the increase in correlation strength becomes minimal. Moreover, the rescue effect from low-elevation species was significantly more pronounced than that from high-elevation species, resulting in a species richness hump skewed towards lower elevations. Our findings contribute to validating the applicability and limitations of hypotheses related to species distribution, enhancing both theoretical and empirical aspects of research. This provides deeper insights for a more comprehensive and profound understanding of the local dynamics and interactions within the ecosystem.

Chromosomal evolution, environmental heterogeneity, and migration drive spatial patterns of species richness in Calochortus (Liliaceae)

We used nuclear genomic data and statistical models to evaluate the ecological and evolutionary processes shaping spatial variation in species richness in Calochortus (Liliaceae, 74 spp.). Calochortus occupies diverse habitats in the western United States and Mexico and has a center of diversity in the California Floristic Province, marked by multiple orogenies, winter rainfall, and highly divergent climates and substrates (including serpentine). We used sequences of 294 low-copy nuclear loci to produce a time-calibrated phylogeny, estimate historical biogeography, and test hypotheses regarding drivers of present-day spatial patterns in species number. Speciation and species coexistence require reproductive isolation and ecological divergence, so we examined the roles of chromosome number, environmental heterogeneity, and migration in shaping local species richness. Six major clades-inhabiting different geographic/climatic areas, and often marked by different base chromosome numbers (n = 6 to 10)-began diverging from each other ~10.3 Mya. As predicted, local species number increased significantly with local heterogeneity in chromosome number, elevation, soil characteristics, and serpentine presence. Species richness is greatest in the Transverse/Peninsular Ranges where clades with different chromosome numbers overlap, topographic complexity provides diverse conditions over short distances, and several physiographic provinces meet allowing immigration by several clades. Recently diverged sister-species pairs generally have peri-patric distributions, and maximum geographic overlap between species increases over the first million years since divergence, suggesting that chromosomal evolution, genetic divergence leading to gametic isolation or hybrid inviability/sterility, and/or ecological divergence over small spatial scales may permit species co-occurrence.

Lizard richness in mainland China is more strongly correlated with energy and climatic stability than with diversification rates

AbstractAimContemporary environmental, historical and evolutionary factors are increasingly used to decipher the drivers of spatial patterns of species richness. Evidence of such correlations for Chinese reptiles is scarce and poorly understood. We therefore explored the validity of the environmental capacity, historical climatic stability and diversification rates hypotheses on Chinese lizard richness.LocationMainland China.TaxonSquamata: Sauria.MethodsWe mapped the distribution ranges of all 237 lizards in mainland China using a combination of different datasets. We used current environmental conditions (ambient energy, environmental productivity, and habitat heterogeneity), historical climate stability indices (long term: since ~3.3 Ma and short term: since the last glacial maximum) and mean tip diversification rates, to test whether current environmental conditions, historical climate change and diversification rates drive contemporary richness patterns of lizards in China. We applied piecewise structural equation models (pSEM) to jointly evaluate our hypotheses, considering direct and indirect effects.ResultsChinese lizards showed strong latitudinal diversity gradients. We found consistent support for contemporary climatic and environmental factors relationships with richness. Richness was also positively correlated with short‐term climatic stability, but less so with long‐term stability. Diversification rates were seldom found to be positively correlated with lizard richness.Main ConclusionsOur results support the environmental capacity and historical climate hypotheses, which link high richness to highly productive warm and stable regions (and low richness to cold and unstable regions). We conclude that post‐speciation dispersal and short‐term climatic oscillations quickly swamp the long‐term signal of diversification rates and climatic fluctuations, creating strong current climate–richness associations.

An early warning for better planning of agricultural expansion and biodiversity conservation in the Orinoco high plains of Colombia

The eastern high plains of the Orinoco region in Colombia are known as ‘Altillanura’. They are considered the future agricultural frontier of Colombia. Unfortunately, an agricultural expansion without taking in consideration areas of high biodiversity and conservation of fragile ecosystems that are ecologically irreplaceable will likely fail in providing a sustainable grow. An orderly management planning of the territory based on scientific evidence is currently lacking for this region. Specifically, studies that combine biodiversity data and agricultural information are a major research gap. This study analyses the spatial patterns of species richness and endemism of flora and fauna at the site and subregional levels. We compared the spatial changes of biodiversity patterns with aspects related to the expansion of the agricultural frontier and its possible impacts. We found a west-to-east pattern; sites closer to the Andes were more exposed to ecological degradation than those in the east. Santa Rosalía and Puerto Lopez are the municipalities with the most remarkable species diversity. Conversely, La Primavera municipality has the most significant number of endemic species. Our spatial changes results raise the alarm showing that hotspots of diversity closer to the municipalities of Puerto Lopez and Puerto Gaitan are under more pressure than underdeveloped municipalities (La Primavera and Puerto Carreño). Our results could serve as a baseline to identify spatial changes of agrobiodiversity and a guideline for land-use planning, regional policies and local decision-makers to improve regional development in Colombia’s eastern plains region.

Quantitative evaluation of the drivers of species richness in a Mediterranean ecosystem (Cape, South Africa).

Mediterranean ecosystems have a high vascular plant species richness (SR) relative to their surface area. This SR, representing the balance between speciation and extinction, has been attributed to multiple mechanisms that result in both high rates of speciation and/or low rates of extinction. An abiding question is, however, what is special about Mediterranean ecosystems that enables this high SR? Apart from the long-term climatic stability of the region, SR has also been related to resource availability, the many individuals hypothesis, resource spatial heterogeneity, temporal heterogeneity and biotic feedbacks. Spatial patterns of species richness were related to climatic, edaphic and biotic variables and to spatial variability within the Greater Cape Floristic Region (GCFR) of South Africa. Boosted regression tree models were used to explore the strength of relationships between SR and environmental predictors related to each hypothesized mechanism. Water availability (i.e. precipitation) was a stronger predictor of SR than potential evapotranspiration or temperature. Scarcity of nutrients was also related to SR. There was no indication that SR was related to the density of individuals and only temporal heterogeneity induced by fire was related to SR. Spatial heterogeneities of climatic, edaphic and biotic variables were strongly associated with SR. Biotic interactions remain difficult to assess, although we have some evidence for a putative role in regulating SR. While the lack of ecosystem-resetting disturbances (e.g. glaciation) is undoubtedly a key requirement for high species accumulation, predictably, no one explanation holds the key to understanding SR. In the GCFR high SR is the product of a combination of adequate water, nutrient scarcity, spatial and temporal heterogeneity, and possibly biotic feedbacks.

Evolution of family Arecaceae on the Indian Plate modulated by the Early Palaeogene climate and tectonics

Arecaceae (palms) is a pantropical plant family with an ancient origin. It shows distinct spatial patterns of species richness in tropical regions having greatest diversity within the Neotropical regions and Southeast Asia. The wider palaeobiogeographic records of palms in relation to current distribution requires a re–examination of their palaeobiogeographic history. The present study reports eleven fossil pollen form–species from the early Palaeogene of India, enhancing our understanding of the evolution of four palm subfamilies: Arecoideae, Calamoideae, Coryphoideae and Nypoideae, on the Indian Plate prior to the India–Asia collision. We suggest the dispersal of diverse palms from Africa to India via the Kohistan– Ladakh Island Arc during Maastrichtian–Palaeocene as part of the Africa–India Floristic Interchange. Subsequently, with wet and humid climates across much of the Indian Plate during the Palaeocene–early Eocene, they underwent a phase of diversification and adaptation leading to habitat expansion. Thus, Indian Plate served as an evolutionary hotspot for the diversification of palms during the early Palaeogene. An in–depth investigation of Palaeogene palm fossils revealed that many palms, currently endemic to Southeast Asia, initially evolved and diversified on the Indian Plate and later dispersed to Southeast Asia following India–Asia collision. The present study thus favours the “Out–of–India” dispersal hypothesis for the Asian palms. The expansion of seasonal climates, and aridification during Neogene and Quaternary led extinction in numerous palm lineages on the Indian subcontinent. This study proposes that deep time climate change and plate tectonism have highly influenced the heterogeneity in spatial and temporal distribution of Asian palms.

Species Richness of Papilionidae Butterflies (Lepidoptera: Papilionoidea) in the Hengduan Mountains and Its Future Shifts under Climate Change.

The family of Papilionidae (Lepidoptera: Papilionoidea) is a group of butterflies with high ecological and conservation value. The Hengduan Mountains (HMDs) in Southwest China is an important diversity centre for these butterflies. However, the spatial distribution pattern and the climate vulnerability of Papilionidae butterflies in the HDMs remain unknown to date. The lack of such knowledge has already become an obstacle in formulating effective butterfly conservation strategies. The present research compiled a 59-species dataset with 1938 occurrence points. The Maxent model was applied to analyse the spatial pattern of species richness in subfamilies Parnassiinae and Papilioninae, as well as to predict the response under the influence of climate change. The spatial pattern of both subfamilies in the HDMs has obvious elevation prevalence, with Parnassiinae concentrated in the subalpine to alpine areas (2500-5500 m) in western Sichuan, northwestern Yunnan and eastern Tibet, while Papilioninae is concentrated in the low- to medium-elevation areas (1500-3500 m) in the river valleys of western Yunnan and western Sichuan. Under the influence of climate change, both subfamilies would exhibit northward and upward range shifts. The majority of Parnassiinae species would experience drastic habitat contraction, resulting in lower species richness across the HDMs. In contrast, most Papilioninae species would experience habitat expansion, and the species richness would also increase significantly. The findings of this research should provide new insights and a clue for butterfly diversity and climatic vulnerability in southwestern China. Future conservation efforts should be focused on species with habitat contraction, narrow-ranged distribution and endemicity with both in situ and ex situ measures, especially in protected areas. Commercialised collecting targeting these species must also be regulated by future legislation.

Warming drives poleward range contractions of Beringian endemic plant species at high latitudes

AbstractAimSpecies are expected to disperse poleward in response to climate change. For species that are endemic to the high latitudes, this implies that many in the future would face a “no‐where‐to‐go” situation as they are currently occupying the northernmost portion of the continent. Further, because endemism may arise from a combination of physical barriers, climate and geological history, the persistence of many species may require spatial matching of multiple environmental factors within a limited dispersal space. Thus, it is not clear how endemic species might spatially adjust their distributions in response to climate change and whether there are future climate change refugia for these species.LocationNorthwest North America.TaxaPlants.Time PeriodCurrent and the future (2040).MethodsWe used ensemble bioclimatic models to evaluate drivers and directional patterns of future change in the distributions of 66 North American Beringian and amphi‐Beringian species currently occurring in Alaska and the Yukon. We explored the spatial pattern of species richness, losses and climate change refugia across the region.ResultsMore than 80% of the species showed northward shifts in their latitudinal centroids under intermediate warming and are expected to shift their range northward by more than 140 km on average by 2040. Additionally, more than 60% were projected to experience range contractions and up to 20% of the species would have the potential to expand their ranges by more than 100%.Main ConclusionsSuitable habitat for endemic species in northwest North America is expected to decline significantly, especially for species occupying the Arctic tundra. Although the models identified several potential refugia from future climate change, especially at high latitude and elevation, whether the species would be able to colonize new habitats on their own and/or capitalize sufficiently on in situ refugia remains a pertinent conservation question.

The role of big trees and abundant species in driving spatial patterns of species richness in an Australian tropical rainforest.

Big trees and abundant species dominate forest structure and composition. As a result, their spatial distribution and interactions with other species and individuals may contribute disproportionately to the emergence of spatial heterogeneity in richness patterns. We tested scale‐dependent spatial patterning and species richness structures to understand the role of individual trees (big trees) and species (abundant species) in driving spatial richness patterns on a 25 ha plot in a diverse tropical forest of Australia. The individual species area relationship (ISAR) was used to assess species richness in neighborhoods ranging from 1 to 50 m radii around all big trees (≥70 cm dbh, n = 296) and all species with more than 100 individuals in the plot (n = 53). A crossed ISAR function was also used to compute species richness around big trees for trees of different size classes. Big individuals exert some spatial structuring on other big and mid‐sized trees in local neighborhoods (up to 30 m and 16 m respectively), but not on small trees. While most abundant species were neutral with respect to richness patterns, we identified consistent species‐specific signatures on spatial patterns of richness for 14 of the 53 species. Seven species consistently had higher than expected species richness in their neighborhood (species “accumulators”), and seven had lower than expected (species “repellers”) across all spatial scales. Common traits of accumulators and repeller species suggest that niche partitioning along disturbance gradients is a primary mechanism driving spatial richness patterns, which is then manifested in large‐scale spatial heterogeneity in species distributions across the plot.

Phylogenetic structure of alien and native species in regional plant assemblages across China: Testing niche conservatism hypothesis versus niche convergence hypothesis

AbstractAimThe introduction of alien species may be influenced by the phylogenetic structure of the native assemblage, while at the same time altering that structure. Understanding these effects sheds light on both the factors influencing naturalization of introduced species and their impacts. Considering regional angiosperm assemblages across China, we ask the following questions: (a) Do geographic patterns and climate relationships of alien species richness and phylogenetic structure mirror those of natives? (b) Has the addition of alien species resulted in stronger phylogenetic clustering as predicted by Darwin's preadaptation hypothesis? (c) To what degree does the answer to these questions depend on phylogenetic scale?LocationChina.Time periodCurrent.TaxonAngiosperms (flowering plants).MethodsWe divided China into 28 province‐level regions and collated native and naturalized alien species lists of angiosperms for each region. For each region, we computed two types of phylogenetic structure metrics [mean phylogenetic distance (MPD) and mean nearest neighbour distance (MNND), and their standardized effect sizes] for the native, alien and combined assemblages, and for angiosperms as a whole, 5 major clades and 10 well‐represented families. We then related these to climatic factors using correlation analyses.ResultsRichness of alien angiosperms is highest in regions with species rich and phylogenetically dispersed native assemblages. The standardized effect size of mean phylogenetic distance (MPDses) for aliens was positively correlated with that for natives. The introduction of alien species generally increased phylogenetic clustering of the combined assemblage compared to the natives for large phylogenetic extents, but effects within plant families were mixed. The MPDses was positively correlated with temperature and precipitation for both natives and aliens.Main conclusionsThe phylogenetic relationships at a lower level of phylogenetic scale may differ substantially from those at a higher level of phylogenetic scale. At the broadest phylogenetic extents, alien species tend to recapitulate the biogeographic patterns of natives, showing similar spatial patterns of species richness and phylogenetic structure, and tending to represent the same major angiosperm clades. This is highly consistent with Darwin's preadaptation hypothesis. Across narrower swaths of the phylogeny, these patterns are less clear, with a substantial number of plant families showing support for the biogeographic barrier hypothesis.

Identifying hotspots and priority areas for xenarthran research and conservation

AbstractAimLimited funds for conservation and research require the development of prioritization schemes. Traditionally, biodiversity metrics were used to delineate priority areas; however, a growing realization emphasizes that logistic factors should be also considered. Here, we combine species richness, past collection efforts, degree of habitat loss and accessibility to define priority areas and spatially orient fieldwork in a cost‐effective manner for xenarthrans.LocationNeotropics.MethodsWe assessed spatial patterns of species richness in Xenarthra and identified diversity hotspots based on species distribution models. Spatial patterns and biases in the Xenarthra past collection efforts were analysed using a comprehensive database including 33,464 individual records for 34 species of Xenarthra. Finally, we produced priority area indices relating species richness and collection efforts with levels of habitat loss and accessibility (roads and rivers network) to highlight important but neglected areas.ResultsCollection efforts were concentrated to a small portion of the Neotropics (central‐western Brazil, eastern Bolivia and north‐western Argentina) and were biased towards access routes. Only 4% of the Neotropics can be considered well sampled. Major xenarthran diversity hotspots include the Amazonian lowlands of Bolivia and the dry Chaco of Paraguay and Argentina. Priority areas for research varied depending on the metric analysed. Amazon holds a high diversity that remains poorly explored. Central Argentina and eastern Brazil are priority areas for research and conservation given the low sampling efforts, high diversity and endemic species, high levels of habitat loss and a dense road network.Main conclusionsMost areas of the Neotropics lack a proper assessment of the xenarthran assemblage, reflecting extensive knowledge shortfalls. Sites close to roads tend to be better sampled, but many areas with a dense road network are undersampled, being good candidates for low‐cost studies. Xenarthra diversity hotspots facing the highest levels of habitat alteration are the least protected and are priority for both research and conservation. Simultaneous efforts of data collection and conservation actions across most of the xenarthran range should be stimulated.

中国蔷薇属植物物种丰富度分布格局及其与环境因子的关系

物种丰富度的大尺度地理格局及其成因是宏观生态学及生物地理学的中心议题之一。蔷薇属（Rosa L.）植物具有很高的经济价值和生态价值，探讨中国蔷薇属植物的丰富度分布格局及其影响因素可为该属植物资源的保护和合理开发利用乃至其系统进化研究提供重要依据。基于蔷薇属植物在中国的15451条分布数据和11种地理、气候等环境因子进行了物种丰富度分析和相关性分析，研究结果显示：（1）蔷薇属植物在中国分布不均匀。在水平方向上，蔷薇属植物于26.19°-34.29°N带内有较高的物种丰富度，之后随着纬度的增加而降低，且随着经度的增加表现为先增加后减少，于99.10°-108.47°E间存在明显的峰值；在垂直方向上，蔷薇属植物的物种丰富度随海拔的增加表现为先增加后减少，956.46-3518.60m范围内的丰富度最高。西南横断山区为蔷薇属物种分布的中心地区，新疆北部及东北长白山周边地区为局部聚集区。（2）蔷薇属物种丰富度与各能量、水分和生境异质性因子均呈正相关关系，与气候稳定性因子呈负相关关系。表明中国蔷薇属植物在水分和热量条件好、气候季节性变化小且生境异质性程度高的地方，有着更高的物种丰富度。（3）蔷薇属植物丰富度与各因子的关系基本支持了生产力假说、环境稳定性假说和生境异质性假说。但蔷薇属的物种丰富度格局并非完全由这些假说解释，历史环境、地形、土壤、人类活动等其他因子可能也有一定的影响作用。（4）水分因子的单独解释率占34.6%（R²；P<0.001），是影响蔷薇属物种丰富度格局的主导因子，这可能是由该类群的进化历史、生理适应等原因共同决定的。本研究可以为蔷薇属植物的分类、进化、以及野生资源的保护和开发利用提供参考。;Understanding macro-scale spatial patterns in species richness and their underlying mechanisms is an important issue to macroecology and biogeography. Rosa species have a high economic and ecological value. Exploring the geographic patterns of species richness and their environmental determinants of Rosa in China will facilitate the resources protection and rational utilization, as well as systematic and evolutionary research of the genus. In this study, datasets of 15451 distributional records and 11 environmental factors were used to conduct species richness and correlation analyses. The results show that (1) Rosa is unevenly distributed in China. The species richness is the highest at latitudes ranging from 26.19°N to 34.29°N, and decreases as the latitude increase. The richness of Rosa is the highest at longitudes ranging from 99.10°E to 108.47°E, and decreased from this optimal range to the west and the east. The species richness shows unimodal pattern that increases first and then decreases with the increase of altitude, with the maximum value between 956.46 m and 3518.60 m. The central aggregation areas are located in the mountain areas around Sichuan Basin as well as Hengduan Mountains, and Chang Bai Mountains region and northern Xinjiang are the local aggregation areas. (2) The energy, water and habitat heterogeneity are positively associated with species richness. In addition, there are negative correlations between species richness and environmental stability. The Rosa has higher species richness in regions with the suitable hydrothermal conditions, the steady climate, and the great habitat heterogeneity. (3) The relationship between the species richness and the environment factors basically supports the productivity hypothesis, the environmental stability hypothesis and the habitat heterogeneity hypothesis. However, the hypotheses cannot fully explain the species richness pattern of Rosa, which indicates that other factors such as historical environment, terrain, soil properties or human activity probably have played a role in shaping the richness pattern of Rosa species. (4) Water factors account for 34.6% (P<0.001) of the species richness patterns of Rosa, so water is the dominant factor, which might be determined by the evolutionary history, physiological adaptation and other reasons. Our results can provide valuable information for the classification, evolution, protection and exploitation of wild resources of the Rosa species.

Genetic and species-level biodiversity patterns are linked by demography and ecological opportunity.

The processes that give rise to species richness gradients are not well understood, but may be linked to resource-based limits on the number of species a region can support. Ecological limits placed on regional species richness should also affect population demography, suggesting that these processes could also generate genetic diversity gradients. If true, we might better understand how broad-scale biodiversity patterns are formed by identifying the common causes of genetic diversity and species richness. We develop a hypothetical framework based on the consequences of regional variation in ecological limits set by resource availability and heterogeneity to simultaneously explain spatial patterns of species richness and neutral genetic diversity. Repurposing raw genotypic data spanning 38 mammal species sampled across 801 sites in North America, we show that estimates of genome-wide genetic diversity and species richness share spatial structure. Notably, species richness hotspots tend to harbor lower levels of within-species genetic variation. A structural equation model encompassing eco-evolutionary processes related to resource availability, habitat heterogeneity, and contemporary human disturbance supports the spatial patterns we detect. These results suggest broad-scale patterns of species richness and genetic diversity could both partly be caused by intraspecific demographic and evolutionary processes acting simultaneously across species.

Legacy effects of seed dispersal mechanisms shape the spatial interaction network of plant species in Mediterranean forests

Abstract Seed dispersal by frugivores plays a key role in structuring and maintaining tree diversity in forests. However, little is known about how the spatial legacy of seed dispersal and early recruitment shapes spatial patterns and the spatial interaction network of plant species in mature forest communities. We analysed two fully mapped mixed Pine–Oak forest communities using spatial point pattern analysis to determine (a) the detailed structure of the intraspecific spatial patterns of saplings and adults, (b) the intra‐ and interspecific spatial interaction of saplings, adults and saplings relative to adults, (c) the spatial patterns of species richness at the community level and (d) whether seed dispersal mechanisms affect the plant–plant interaction networks and the ratio of adult to sapling neighbourhood densities used as surrogate for spatial self‐thinning. The intraspecific spatial patterns of saplings and adults showed in general complex nested cluster structures that were similar for sapling and adult stages, despite substantial self‐thinning in some dry‐fruited species. The spatial network of saplings was characterized by positive spatial interactions. Adults of several tree species facilitated saplings in their proximity; however, adults of dry‐fruited species, but not those of fleshy‐fruited ones, lost almost all positive interactions that occurred at the sapling stage. Besides, interaction strength between adults was positive and often significantly stronger if both species were fleshy‐fruited. At the community level, the forests were structured into multispecies clumps across all life stages. Synthesis. Our analyses highlight the importance of the spatial legacy of seed dispersal and early recruitment in the assembly of plant communities. Particularly, animal seed dispersal can lead to multispecies clusters and positive spatial associations across life stages in Mediterranean forests, with surprisingly little signatures of negative interactions. Our analysis suggests that changes of the spatial structure across plant life stages are driven by seed dispersal mechanisms and subsequent spatial self‐thinning, generating a spatial footprint at the sapling stage that conditions the long‐term interactions between adult plants. Combining spatial point pattern analysis with network analysis and species traits is a promising way to disentangle the processes underlying observed patterns of local diversity.

Mapping Potential Plant Species Richness over Large Areas with Deep Learning, MODIS, and Species Distribution Models

The spatial patterns of species richness can be used as indicators for conservation and restoration, but data problems, including the lack of species surveys and geographical data gaps, are obstacles to mapping species richness across large areas. Lack of species data can be overcome with remote sensing because it covers extended geographic areas and generates recurring data. We developed a Deep Learning (DL) framework using Moderate Resolution Imaging Spectroradiometer (MODIS) products and modeled potential species richness by stacking species distribution models (S-SDMs) to ask, “What are the spatial patterns of potential plant species richness across the Korean Peninsula, including inaccessible North Korea, where survey data are limited?” First, we estimated plant species richness in South Korea by combining the probability-based SDM results of 1574 species and used independent plant surveys to validate our potential species richness maps. Next, DL-based species richness models were fitted to the species richness results in South Korea, and a time-series of the normalized difference vegetation index (NDVI) and leaf area index (LAI) from MODIS. The individually developed models from South Korea were statistically tested using datasets that were not used in model training and obtained high accuracy outcomes (0.98, Pearson correlation). Finally, the proposed models were combined to estimate the richness patterns across the Korean Peninsula at a higher spatial resolution than the species survey data. From the statistical feature importance tests overall, growing season NDVI-related features were more important than LAI features for quantifying biodiversity from remote sensing time-series data.

Estimating aquatic plant diversity and distribution in rivers from Jingjinji region, China, using environmental DNA metabarcoding and a traditional survey method

Traditional survey methods (TSMs) are difficult to use to perform a census of aquatic plant diversity completely in river ecosystems, and improved aquatic plant community monitoring programs are becoming increasingly crucial with a continuous decline in diversity. Although environmental DNA (eDNA) metabarcoding has been applied successfully to assess aquatic biodiversity, limited work has been reported regarding aquatic plant diversity in rivers. In this study, the efficiency of eDNA to estimate the aquatic plant diversity and spatial distribution of rivers from the Jingjinji (JJJ) region was evaluated by comparing results obtained by the TSM. Based on a combination of the two methods, 157 aquatic plant species, including 24 hydrophytes, 61 amphibious plants, and 72 mesophytes, were identified. The spatial patterns in species richness and abundance by eDNA exhibited agreement with the TSM results with a gradual decline from the mountain area (MA) to the agricultural area (AA) and then to the urban area (UA). Compared to the TSM, eDNA identified a significantly greater number of species per site (p < 0.01) and obtained a significantly higher abundance in hydrophytes (p < 0.01), supplementing the unavailable abundance data from the TSM. Furthermore, the aquatic plant assemblages from the different areas were discriminated well using eDNA (p < 0.05), but they were better discriminated by the TSM (p < 0.01). Thus, our study provides more detailed data on aquatic plant diversity in rivers from the JJJ region, which is essential for biodiversity conservation. Our findings also highlight that eDNA can be reliable for evaluating aquatic plant diversity and has the potential to respond to landscape heterogeneity in river ecosystems.

Land snail biogeography and endemism in south-eastern Africa: Implications for the Maputaland-Pondoland-Albany biodiversity hotspot.

Invertebrates in general have long been underrepresented in studies on biodiversity, biogeography and conservation. Boundaries of biodiversity hotspots are often delimited intuitively based on floristic endemism and have seldom been empirically tested using actual species distributions, and especially invertebrates. Here we analyse the zoogeography of terrestrial malacofauna from south-eastern Africa (SEA), proposing the first mollusc-based numerical regionalisation for the area. We also discuss patterns and centres of land snail endemism, thence assessing the importance and the delimitation of the Maputaland-Pondoland-Albany (MPA) biodiversity hotspot for their conservation. An incidence matrix compiled for relatively well-collected lineages of land snails and slugs (73 taxa in twelve genera) in 40 a priori operational geographic units was subjected to (a) phenetic agglomerative hierarchical clustering using unweighted pair-group method with arithmetic means (UPGMA), (b) parsimony analysis of endemicity (PAE) and biotic element analysis (BEA). Fulfilling the primary objective of our study, the UPGMA dendrogram provided a hierarchical regionalisation and identified five centres of molluscan endemism for SEA, while the PAE confirmed six areas of endemism, also supported by the BEA. The regionalisation recovers a zoogeographic province similar to the MPA hotspot, but with a conspicuous westward extension into Knysna (towards the Cape). The MPA province, centres and areas of endemism, biotic elements as well as the spatial patterns of species richness and endemism, support the MPA hotspot, but suggest further extensions resulting in a greater MPA region of land snail endemism (also with a northward extension into sky islands—Soutpansberg and Wolkberg), similar to that noted for vertebrates. The greater MPA region provides a more robustly defined region of conservation concern, with centres of endemism serving as local conservation priorities.

Disentangling the role of environment in cross-taxon congruence of species richness along elevational gradients

Spatial patterns of species richness have been found to be positively associated, a phenom called cross-taxon congruence. This may be explained by a common response to environment or by ecological interactions between taxa. Spatial changes in species richness are related to energy and environmental heterogeneity but their roles in cross-taxon congruence remain poorly explored. Elevational gradients provide a great opportunity to shed light on the underlying drivers of species richness patterns. We study the joint influence of environment and biotic interactions in shaping the cross-taxon congruence of plants and orthopterans species richness, along three elevational gradients in Sierras Grandes, central Argentina. Elevational patterns of species richness of orthopterans and plants were congruent, being temperature the best single predictor of both patterns supporting the energy-related hypotheses. Using a structural equation model, we found that temperature explained plant richness directly and orthopteran richness indirectly via orthopteran abundance. Cross-taxon congruence is likely due to a common response of both taxa to temperature although via different theoretical mechanisms, possibly, range limitations for plants and foraging activity for orthopterans. We disentangled the role of temperature in determining the cross-taxon congruence of plants and orthopterans by showing that a common response to the environment may mask different mechanisms driving the diversity of different taxonomic groups.

Spatial homogenization of understorey plant communities under eCO2 in a mature Eucalyptus woodland

Abstract Understorey plant communities comprise a large portion of biodiversity of forests and woodlands globally, where they contribute to tree species dynamics, biogeochemical cycling and carbon sequestration. Here we evaluated the effects of elevated CO2 (400 vs. 550 ppm) on the spatial distribution of understorey plant communities from a mature eucalypt woodland in Eastern Australia (EucFACE experiment). Three years of elevated CO2 resulted in a loss of the characteristic aggregated and segregated spatial pattern of species richness at both short and long distances (20 cm–227 cm), respectively. Changes in spatial patterns emerged over time, indicating that these results are due to a relatively slow reordering of the understorey plant community. In contrast, when analysed from a multivariate perspective, changes in terms of community composition were not as clear as changes in the spatial rearrangement of plant communities. Synthesis. Given that the spatial patterns of communities are likely a reflection of the way in which multiple species interact and how energy and matter flow throw ecosystems, community reordering due to global change may have far‐reaching implications in terms of ecosystem functioning. Moreover, subtle early changes in the spatial pattern of understorey plant communities may represent an early‐warning indicator of global change impacts in forest ecosystems.