Patterns Of Species Diversity Research Articles

Variation in Species Diversity of Epilithic Bryophytes Along the Karst Rocky Desertification Gradient

Karst rocky desertification is a distinctive landscape formed by the exposure of rock surfaces, where epilithic bryophytes dominate the plant communities. Despite their prevalence, these mosses have received relatively little attention, and the species diversity of lithophilous mosses remains inadequately understood. In this study, we conducted field collections and laboratory identifications of epilithic bryophytes across various karst habitats exhibiting different levels of rocky desertification, aiming to elucidate the patterns of species diversity within these environments. Our findings reveal a total of 47 moss species, belonging to 11 families and 28 genera, with species distribution patterns as follows: PRD (22 species) > MRD (18 species) > SRD (14 species) > NRD (12 species) > LRD (11 species). Notably, the PRD and MRD habitats harbor the highest number of endemic species, each with 8 endemic species, while the other three habitats each contain 5 endemic species. Among these, Eurohypnum leptothallum is a common species across all habitats and represents a dominant species in the karst region. Four distinct moss growth forms were identified in the study area, with proportions as follows: Wefts (75%) > Turfs (15%) > Pentants (8%) > Cushion (2%). The Wefts growth form is ubiquitous across all habitats and is the most prevalent, whereas the proportion of Pendants increases along the rocky desertification gradient, showing a higher degree of adaptation to more severely desertified environments. The α-diversity indices (richness index (R), Simpson index (D), Pielou index (E), and Shannon-Wiener index (H)) exhibit an "M"-shaped distribution along the desertification gradient, indicating the selective effects of desertification processes and the dynamic changes in species over time. The β-diversity index further suggests low species similarity between different habitats, with the similarity index (Cs) between NRD and SRD habitats being as low as 0.08, signifying substantial shifts in species composition. These results provide valuable insights into the changes in species diversity of lithophilous mosses along the rocky desertification gradient and enhance our understanding of the moss species diversity in karst rocky desertification areas.

Multi-factors monitoring enhances comprehension of the species diversity, structure and zonation patterns of Dafengjiang mangrove wetland in Beibu Gulf

Multi-factors monitoring enhances comprehension of the species diversity, structure and zonation patterns of Dafengjiang mangrove wetland in Beibu Gulf

Global patterns of species diversity and distribution in the biomedically and biotechnologically important fungal genus Aspergillus.

Aspergillus fungi are key producers of pharmaceuticals, enzymes, and food products and exhibit diverse lifestyles, ranging from saprophytes to opportunistic pathogens. To improve understanding of Aspergillus species diversity, identify key environmental factors influencing their geographic distributions, and estimate the impact of future climate change, we trained a random forest machine learning classifier on 30,542 terrestrial occurrence records for 176 species (~40% of known species in the genus) and 96 environmental variables. We found that regions with high species diversity are concentrated in temperate forests, which suggests that areas with mild seasonal variation may serve as diversity hotspots. Species range estimates revealed extensive variability, both within and across taxonomic sections; while some species are cosmopolitan, others have more restricted ranges. Furthermore, range overlap between species is generally low. The top predictors of mean species richness were the index of cumulative human impact and five bioclimatic factors, such as temperature and temperate vs non-temperate ecoregions. Our future climate analyses revealed considerable variation in species range estimates in response to changing climates; some species ranges are predicted to expand (e.g., the food spoilage and mycotoxin-producing Aspergillus versicolor), and others are predicted to contract or remain stable. Notably, the predicted range of the major pathogen Aspergillus fumigatus was predicted to decrease in response to climate change, whereas the range of the major pathogen Aspergillus flavus was predicted to increase and gradually decrease. Our findings reveal how both natural and human factors influence Aspergillus species ranges and highlight their ecological diversity, including the diversity of their responses to changing climates, which is of relevance to pathogen and mycotoxin risk assessment.

Prevalence, risk factors, and species diversity of strongylid nematodes in domesticated Thai horses: insights from ITS-2 rDNA metabarcoding.

Strongylid nematodes represent a major health and performance concern for equids globally. However, the epidemiology of strongylid infections in horse populations remains largely unexplored in Thailand. This study investigated the prevalence of strongylid parasites and the associated risk factors in domesticated horses in Thailand. Additionally, the study utilized ITS-2 rDNA metabarcoding to characterize the diversity and co-occurrence patterns of strongylid species. Of the 408 horses examined, 50.98% tested positive for strongyle infection, with an average intensity of 445.67 ± 639.58 eggs. Notably, only 25.74% exhibited fecal egg counts of ≥ 200 eggs per gram (EPG), highlighting the need for targeted deworming protocols. Significantly higher EPG values were observed in yearling horses (p = 0.001) and those kept in outdoor pastures (p = 0.0001). Metabarcoding identified 15 strongylid species, with Cylicostephanus longibursatus being the most abundant (mean relative abundance: 37.30%, SD = 31.16%). No Strongylus species were detected. Alpha diversity analysis revealed no significant differences in species richness and evenness across horse groups, while beta diversity analysis showed significant dissimilarities (p = 0.004), primarily driven by Cylicostephanus longibursatus, Cyathostomum pateratum, and Cylicostephanus calicatus, which contributed to over 60% of the variation. Species co-occurrence patterns were largely random, with a limited number of positive (n = 5) and negative (n = 2) species pair associations. These findings provide essential insights into the current state of strongylid infections in Thai horses and offer a foundation for future research and management strategies.

Phylotranscriptomic and ecological analyses reveal the evolution and morphological adaptation of Abies.

Coniferous forests are under severe threat of the rapid anthropogenic climate warming. Abies (firs), the fourth-largest conifer genus, is a keystone component of the boreal and temperate dark-coniferous forests and harbors a remarkably large number of relict taxa. However, the uncertainty of the phylogenetic and biogeographic history of Abies significantly impedes our prediction of future dynamics and efficient conservation of firs. In this study, using 1,533 nuclear genes generated from transcriptome sequencing and a complete sampling of all widely recognized species, we have successfully reconstructed a robust phylogeny of global firs, in which four clades are strongly supported and all intersectional relationships are resolved, although phylogenetic discordance caused mainly by incomplete lineage sorting and hybridization was detected. Molecular dating and ancestral area reconstruction suggest a Northern Hemisphere high-latitude origin of Abies during the Late Cretaceous, but all extant firs diversified during the Miocene to the Pleistocene, and multiple continental and intercontinental dispersals took place in response to the late Neogene climate cooling and orogenic movements. Notably, four critically endangered firs endemic to subtropical mountains of China, including A. beshanzuensis, A. ziyuanensis, A. fanjingshanensis and A. yuanbaoshanensis from east to west, have different origins and evolutionary histories. Moreover, three hotspots of species richness, including western North America, central Japan, and the Hengduan Mountains, were identified in Abies. Elevation and precipitation, particularly precipitation of the coldest quarter, are the most significant environmental factors driving the global distribution pattern of fir species diversity. Some morphological traits are evolutionarily constrained, and those linked to elevational variation (e.g., purple cone) and cold resistance (e.g., pubescent branch and resinous bud) may have contributed to the diversification of global firs. Our study sheds new light on the spatiotemporal evolution of global firs, which will be of great help to forest management and species conservation in a warming world.

Genotyping and drug susceptibility profiling of Prototheca sp. strains isolated from cases of protothecosis in dogs.

Protothecosis in dogs is a rare, yet emerging disease, distinguished by its often-aggressive clinical course and high fatality rate. Our study was conducted to enhance treatment protocols for affected dogs by better understanding the genetic diversity and drug resistance patterns of Prototheca species. To identify species and drug susceptibility profiles of an international collection of 28 Prototheca strains isolated from cases of protothecosis in dogs. None. Retrospective study. Species-level identification was made for isolates from 28 dogs in 6 countries by molecular typing with the partial cytb gene as a marker. For the determination of minimum inhibitory concentrations (MICs) and minimum algicidal concentrations (MACs), the Clinical Laboratory Standards Institute (CLSI) protocol (M27-A3) was used. Prototheca bovis was the most prevalent species, accounting for 75% (21/28) of the cases, followed by P. wickerhamii (18%; 5/28) and P. ciferrii (7%; 2/28). Of the 6 drugs tested, efinaconazole (EFZ) was the most potent in vitro, with its median MIC and MAC values equal to 0.125 mg/L. The lowest activity was found for fluconazole (FLU), with MIC and MAC medians of 48 mg/L and 64 mg/L, respectively. Our study identifies P. bovis as the species that most frequently causes protothecosis in dogs, which suggests the possibility of cross-species infection from other animals, especially cows. Additionally, it indicates that EFZ could be used in the treatment of infection in the colon.

Contrasting diversity patterns of native and alien species across multiple taxa in Central European river corridors

River corridorsare amongthe most important natural pathways for invasive species to spread into landscapes. Nevertheless, the ecological processes underlying invasions of riparian habitats are poorly understood for many taxonomic groups. We sampled bryophytes, vascular plants, and molluscs along three West Carpathian rivers (Central Europe) to identify spatial trends and drivers of native and alien species diversity across multiple taxa. Generalised additive models revealed decreasing downstream diversity patterns across all studied rivers and taxonomic groups. In contrast, alien diversity showed the opposite trend, displaying a high degree of idiosyncrasy among the rivers. Random forest analysis revealed that climate-induced variables (altitude and related temperature) played a more pronounced role in the diversity of alien species than in the diversity of native species. The diversity of native species was more influenced by local land use and habitat alternations (molluscs) or by source-to-mouth river interactions along the longitudinal gradient (plants). Dispersal limitation and temperature constrain alien species distributions along river corridors, while a multitude of natural and anthropic influences drive native species diversity. The climate-driven distribution of alien plants and molluscs suggests future altitudinal and longitudinal shifts in non-native species along river corridors, which will be exacerbated by ongoing climate warming and associated environmental changes.

Biodiversity and Abundance of Angiosperms and Environmental Resilience in the Tidal Range of Yuanjiang Dry–Hot Valley, Southwestern China

Yuanjiang dry–hot valley is located in the southwest of mainland China. It is a sparsely vegetated area with a fragile arid ecosystem. Although the valley previously had forest cover, it has become a tropical montane savannah in recent decades. Mechanisms controlling plant species distribution in such dry–hot valleys are unclear. Clarifying this will be beneficial to sustainable ecosystem management in dry–hot valleys. This study explored the relationship between diversity patterns of plant species and their environments in the lowland of this dry–hot valley. To achieve this, transects and plots were arranged along the river channel. Alpha and beta diversity indices were calculated to quantify biodiversity changes between species and environments. Estimated species, rarity, and abundance indices were also utilized to examine the correlation among species, their population size, and their environment: Species_estimated (expected number of species in t pooled plots), Singletons (the number of species with only one individual in t pooled plots), Uniques (the number of species living in one plot in t pooled plots), ACE (species richness estimator with coverage-based abundance), ICE (species richness estimator with coverage-based incidence), and Chao2 (species richness estimator extrapolated from Singletons). Fifty years of meteorological records, including temperature and precipitation, were utilized as climate variables. The results indicated the following findings: (1) alpha diversity was higher closer to the river, whereas the beta diversity was higher towards the lower sections of the river (Bray–Curtis < 0.5), but this trend was reversed in the perpendicular transects; (2) total phosphorous (TP) and total potassium (TK) were higher on flatter ground, tending to be associated with raised nitrogen (TN) and organic matter (OM); (3) soil nutrients were higher towards the lower sections of the river, corresponding to an increased number of species; (4) water supply determined plant distribution, with soil condition determining water retention; (5) the estimated species and their rarity and abundance indices were associated with proximity to the river, indicating heterogeneity of habitats and soil condition; and (6) fern species could be used as indicators representing the xeric environment of Yuanjiang dry–hot valley. Plant cover was reduced at low altitudes, with high temperatures and a low water supply. These results draw attention to the need for specific policy formation to protect the microhabitats and manage the environment of the Yuanjiang valley.

Spatial pattern of woody plant species richness and composition in primary warm temperate evergreen forest in Kasugayama Hill, Japan

Plant species richness and composition are influenced by complex interactions between biotic and abiotic factors that operate on different spatial scales. Since spatial scales vary continuously in nature, it is expected that multiple factors simultaneously affect species richness and composition at an intermediate spatial scale (i.e., the mesoscale landscape level). Previous studies have shown that local topography and elevation are important factors for shaping intermediate spatial scale plant species richness; however, the relative importance of these factors has rarely been examined. Here, we used spatially explicit woody plant data to examine the factors that characterize the spatial pattern of primary evergreen forest biodiversity at the intermediate spatial scale. We found that the spatial pattern of species diversity in a predominantly warm temperate evergreen forest at the landscape level is mainly characterized by shifts in species composition along the elevation gradient. Our study also found that compositional shift along the elevational gradient was mainly caused by habitat specialization among congeneric species, suggesting that niche partitioning among closely-related species is a fundamentally important feature of the intermediate spatial scale species richness pattern. Furthermore, we found that specialization in a habitat of closely-related species can be established even within a limited environmental gradient. This suggests that biotic interactions among closely-related species may be an important factor driving habitat specialization, and biotic interactions may play an important role in shaping landscape-scale biodiversity patterns.

Soil cover heterogeneity associated with biocrusts predicts patch-level plant diversity patterns

ContextSoil resource heterogeneity drives plant species diversity patterns at local and landscape scales. In drylands, biocrusts are patchily distributed and contribute to soil resource heterogeneity important for plant establishment and growth. Yet, we have a limited understanding of how such heterogeneity may relate to patterns of plant diversity and community structure.ObjectivesWe explored relationships between biocrust-associated soil cover heterogeneity and plant diversity patterns in a cool desert ecosystem. We asked: (1) does biocrust-associated soil cover heterogeneity predict plant diversity and community composition? and (2) can we use high-resolution remote sensing data to calculate soil cover heterogeneity metrics that could be used to extrapolate these patterns across landscapes?MethodsWe tested associations among field-based measures of plant diversity and soil cover heterogeneity. We then used a Support Vector Machine classification to map soil, plant and biocrust cover from sub-centimeter resolution Unoccupied Aerial System (UAS) imagery and compared the mapped results to field-based measures.ResultsField-based soil cover heterogeneity and biocrust cover were positively associated with plant diversity and predicted community composition. The accuracy of UAS-mapped soil cover classes varied across sites due to variation in timing and quality of image collections, but the overall results suggest that UAS are a promising data source for generating detailed, spatially explicit soil cover heterogeneity metrics.ConclusionsResults improve understanding of relationships between biocrust-associated soil cover heterogeneity and plant diversity and highlight the promise of high-resolution UAS data to extrapolate these patterns over larger landscapes which could improve conservation planning and predictions of dryland responses to soil degradation under global change.

Spatial and Temporal Patterns of Grassland Species Diversity and Their Driving Factors in the Three Rivers Headwater Region of China from 2000 to 2021

Biodiversity loss will lead to a serious decline for ecosystem services, which will ultimately affect human well-being and survival. Monitoring the spatial and temporal dynamics of grassland biodiversity is essential for its conservation and sustainable development. This study integrated ground monitoring data, Landsat remote sensing, and environmental variables in the Three Rivers Headwater Region (TRHR) from 2000 to 2021. We established a reliable model for estimating grassland species diversity, analyzed the spatial and temporal patterns, trends of change, and the driving factors of changes in grassland species diversity over the past 22 years. Among models based on diverse variable selection and machine learning methods, the random forest (RF) combined stepwise regression (STEP) model was found to be the optimal model for estimating grassland species diversity in this study, which had an R2 of 0.44 and an RMSE of 2.56 n/m2 on the test set. The spatial distribution of species diversity showed a pattern of abundance in the southeast and scarcity in the northwest. Trend analysis revealed that species diversity was increasing in 80.46% of the area, whereas 16.59% of the area exhibited a decreasing trend. The analysis of driving factors indicated that the changes in species diversity were driven by both climate change and human activities over the past 22 years in the study area, of which temperature was the most significant driving factor. This study effectively monitors grassland species diversity on a large scale, thereby supporting biodiversity monitoring and grassland resource management.

Elevational patterns of bird alpha and beta diversity in Haba Snow Mountain, Southwestern China: Implication for conservation

Understanding environmental patterns of species diversity is essential for nature reserve planning and biodiversity conservation. In this study, we explored the birds’ alpha and beta diversity along the elevational gradients in Haba Snow Mountain Nature Reserve (hereafter, HBSM), a global biodiversity hotspot, and studied which environmental factor is the main driver in explaining alpha and beta diversity patterns. Our results indicated that taxonomic, functional, and phylogenetic alpha diversity consistently exhibited hump-shaped patterns with similar peaks. After controlling for species richness, both functional and phylogenetic alpha diversity increased with elevation, and the peaks at 3400–3700 m. Mean pairwise functional distance remained nearly constant along the elevation band, whereas mean pairwise phylogenetic distance shown hump-shaped pattern, and the predicted MPD peaked at the fifth band (3100–3400 m a.s.l). The functional and phylogenetic structure of bird communities in HBSM were more clustered along the elevation gradients, suggesting environmental filtering likely drove the assembly processes. Additionally, primary productivity (NDVI and/or habitat heterogeneity) and/or precipitation were robust predictors of variation in most diversity metrics. For multiple-site beta diversity, we observed that high turnover component in taxonomic, functional, and phylogenetic dimensions, indicating distinct bird assemblages across various elevational bands. In pairwise beta diversity, the spatial turnover of taxonomic and phylogenetic aspects was higher than nestedness, revealing species replacement occurs relatively frequently between evolutionarily related species with similar niche and functional traits. Overall, our findings highlight the importance of considering both different dimensions and multifaceted diversity when assessing elevational patterns of bird diversity. This study also provides valuable insights into the structuring mechanisms of bird communities and informs conservation planning along elevational gradients in HBSM, and offers a comprehensive case on species richness along elevational gradients.

A primer of community ecology using the R language

AbstractCommunity ecology beginners often struggle to understand theories expressed in complex mathematical formulas and to master computer programming. To remedy this situation, this article provides a practical, R‐based introduction to community ecology by illustrating core concepts (vital rates, carrying capacity, density dependence) and models that can be used to explore the patterns of species abundance and diversity. The structure of this article consists of three modeling exercises, each asking a general question that can be answered by a combination of theory and R programming: (1) what determines the abundance of species, and what makes a population persist and go extinct?; (2) what determines the distribution of species and species diversity?; (3) what determines the relative abundance of species and what allows species to coexist? Through the exercises, I discuss the following five concepts and ideas that provide valuable insights into the questions: (i) the tragedy of the commons, (ii) the theory of island biogeography, (iii) competitive exclusion, (iv) the neutral theory of biodiversity, and (v) frequency dependence. These materials are thus designed to guide the reader in developing an intuition for ecological thinking that will help capture the essence of the global environmental and biodiversity crisis. Although this article does not delineate the scope and depth of the vast field of community ecology, I hope that it will motivate the reader to step up to a more formal introduction to community ecology.

Effects of Urbanization on Community Composition and Conditions of Birds in Wetland Ecosystems

Urbanization in wetlands has negatively impacted bird species diversity and populations. It is important to be able to predict the consequences for avian biodiversity and to identify wetlands of special value to the maintenance of local wetland communities. This study involved conducting point counts across four permanent urban wetlands at the University of Florida and three retention ponds in the Gainesville, FL vicinity to observe patterns in wetland bird species diversity and populations. This study also utilized data from the Florida Museum of Natural History (FLMNH) to explore differences in phenotypes of wetland bird specimens. The local wetlands showed trends where specific species thrived in one type of area versus the other. Egrets were frequently observed in larger wetlands, and double-crested cormorants were observed more frequently in smaller ones. Additionally, retention ponds showed promise as a conservation method, dependent on their depth and size. The largest retention pond attracted many bird species in great numbers, showing promise for methods to negate negative the impact of human activity and climate change. Characterization for data collected at the FLMNH on both weight and species analyzed across numerous regional locations showed a negative trend between specimen weight and time progression.

The species diversity and phylogenetic structure patterns of desert plant communities in the Turpan-Hami region, Xinjiang

Desert plant communities play a crucial role in enhancing desert ecosystem productivity and stability but are highly susceptible to environmental changes owing to their limited resilience and resistance to disturbances, making it essential to understand the factors influencing their diversity patterns and community structure, particularly under the threat of climate change and intensifying droughts. This study focused on the Turpan-Hami desert region, a typical desert ecosystem in which diversity patterns and community structures remain unclear. We established 101 sampling sites ranging from elevations of −134–2056 m and recorded community information, including species composition, height, coverage, and density, using the sample plot method. The diversity patterns were analyzed using regression analysis, and the phylogenetic structure was assessed. Additionally, Canonical Correspondence Analysis, Mantel tests, and General Linear Models were used to identify the key factors affecting community structure. Our results demonstrated that the species richness and phylogenetic diversity of plant communities exhibited a monotonic increase with elevation, and the phylogenetic structure exhibited low clustering and high dispersion along the elevational gradient. The annual mean temperature emerged as the most significant factor influencing diversity patterns, with soil nutrients, such as total potassium and available phosphorus, also affecting the spatial distribution of diversity. Notably, no significant correlations were found between community phylogenetic structure and abiotic factors, highlighting the complex interactions that drive diversity in the Turpan-Hami region. This study offers valuable insights into the mechanisms shaping desert plant community diversity and is essential for biodiversity conservation efforts in fragile desert ecosystems amid climate change.

Tree species diversity impacts on ecosystem services of temperate forests

Tree species diversity is crucial for forest ecosystem services as it relates to ecosystem functions. However, it remains unclear how spatially continuous tree species diversity affects multiple ecosystem services in temperate forests that undergo various management practices. We mapped the spatial pattern of tree species diversity represented by the Shannon diversity index, H’ in the temperate forests of Northeast China using 1,028 in situ observations and 846 Sentinel-2 images. We further analysed the relationships between tree species diversity and ecosystem services including carbon storage, water yield, and soil retention, while controlling for the covarying effects of multiple forest attributes including tree height, leaf area index (LAI), and stand age. Our results showed distinct spatial variations in tree species diversity across different forest management practices, with natural forests exhibiting a higher diversity compared to managed natural forests and planted forests. Tree species diversity was found to be positively associated with improved ecosystem services, particularly water yield and soil retention, while the effects plateaued above diversity of 1.0 (Shannon index values). We also showed that LAI was the most important factor influencing carbon storage, while tree species diversity and stand age were crucial for water yield and soil retention. These results highlight the importance of maintaining diverse tree species to improve ecosystem services in temperate forests, providing a robust framework for effectively monitoring and managing forest ecosystems with regards to sustainable forest functioning.

Diversity pattern of Symplocos tree species in China under climate change scenarios: Toward conservation planning

Symplocos, a genus rich in endemic and keystone species in China's subtropical forests, plays a vital role in maintaining biodiversity. Climate change impacts on Symplocos trees affect ecosystem composition, dynamics, and functions. This study delves into the potential ramifications of climate change on the distribution and richness of Symplocos species across China under different climatic conditions. A comprehensive analysis was conducted using occurrence records of 29 species of Symplocos, focusing on habitat suitability modeling and spatial analysis, to demonstrate the possible effects of climate change on the distribution and diversity patterns of Symplocos species in China. Environmental data, including bioclimatic variables, were collected, and the future climate scenarios were projected using the combined average of the two global climate models. Four modeling algorithms were applied in an ensemble species distribution models to assess the distribution of Symplocos species and decipher the pattern of species richness and endemism. The results indicate high accuracy and performance of the models with a mean AUC of 0.94 and TSS of 0.77, particularly the random forest. The analysis identified key bioclimatic variables influencing Symplocos species distribution, with precipitation patterns (precipitation of driest month and precipitation of warmest quarter) and temperature variability (temperature mean diurnal range) playing significant roles. Predictions suggest a reduction in Symplocos species richness over the next six decades, particularly in southern and southwestern China, with potential gains in other regions. Overall, this study highlights the vulnerability of Symplocos species to climate change and underscores the importance of proactive conservation efforts and forest plantations to mitigate future loss in Symplocos species diversity.

Genetic Variability in Mediterranean Coastal Ecosystems: Insights into Ostrea spp. (Bivalvia: Ostreidae).

Oysters are sessile, filter-feeding bivalve molluscs widely distributed in estuarine and coastal habitats worldwide. They constitute a valuable resource for fisheries and extensive aquaculture and provide essential ecological services. Yet, their genetic diversity and distribution remain understudied. The variability in shell morphology complicates species classification, which is influenced by environmental and genetic factors. Although molecular phylogenetics research has refined oyster taxonomy and identified approximately 100 extant species, numerous taxonomic uncertainties persist. In the present study, we aimed to document the occurrence of small flat oysters of the genus Ostrea along the Mediterranean coastal areas of Liguria and Sardinia (Italy). Specifically, 16S rRNA sequence data were used to identify Ostrea species. Our findings offer novel insights into the O. stentina species complex and O. neostentina, a new species in the Mediterranean coastal areas of Italy. The study data further our understanding of Ostrea species diversity, distribution, and evolutionary patterns.

Habitat suitability and distribution patterns of Rouget's rail (Rougetius rougetii Guérin-méneville, 1843) in Ethiopia.

Geographical distribution and diversity patterns of bird species are influenced by climate change. The Rouget's rail (Rougetius rougetii) is a ground-dwelling endemic bird species distributed in Ethiopia and Eritrea. It is a near-threatened species menaced by habitat loss, one of the main causes of population declines for bird species. The increasing effects of climate change may further threaten the species' survival. So far, the spatial distribution of this species is not fully documented. With this study, we develop current potential suitable habitat and predict the future habitat shift of R. rougetii based on environmental data such as bioclimatic variables, population density, vegetation cover, and elevation using 10 algorithms. We evaluated the importance of environmental factors in shaping the bird's distribution and how it shifts under climate change scenarios. We used 182 records of R. rougetii from Ethiopia and nine bioclimatic, population density, vegetation cover, and elevation variables to run the 10 model algorithms. Among 10 algorithms, eight were selected for ensembling models according to their predictive abilities. The current suitable habitats for R. rougetii were predicted to cover an area of about 82,000 km2 despite being highly fragmented. The model suggested that temperature seasonality (bio4), elevation, and mean daily air temperatures of the driest quarter (bio9) contributed the most to delimiting suitable areas for this species. R. rougetii is sensitive to climate change associated with elevation, which leads shrinking distribution of suitable areas. The projected spatial and temporal pattern of habitat loss of R. rougetii suggests the importance of climate change mitigation and implementing long-term conservation and management strategies for this threatened endemic bird species.

The changes in diversity of vegetation and foliar stable isotopes during the terrestrial plant succession of a subtropical forest and their ecological implications

The disturbed forest system can be restored through successional processes, where changes in the diversity of plant species serves as key indicators of processes. Meanwhile plant water use efficiency and nitrogen dynamics are important factors influencing photosynthesis-water coupling and nutrient stress in plants, respectively, during forest recovery. Analyzing these factors is crucial for understanding forest recovery and promoting sustainable ecosystem development. In this study, traditional vegetation surveys and biodiversity indices, along with foliar stable carbon and nitrogen isotope analyses, as well as nitrogen content analyses, were conducted in a subtropical forest with various successional stages following human and natural disturbances in Sichuan province, China. These analyses were used to assess species diversity patterns, evaluate water use efficiency, and assess nitrogen dynamics in primary, secondary, and artificial forests. The results showed distinct stage-specific differences in succession among forest types. Primary forests exhibited the highest successional stage but were limited by water stress and high nitrogen competition, with the highest δ13C values (i.e., −29.0 ‰), lowest δ15N values (i.e., −3.6 ‰), and the lowest nitrogen contents (i.e., 3.6 %) on average. Artificial forests had the lowest species diversity due to species dominance and nitrogen competition, with the lowest δ13C values (i.e., −29.7 ‰), relatively low nitrogen contents (i.e., 4.0 %), and high δ15N values (i.e., −1.8 ‰). Secondary forests, with longer recovery periods, reached higher successional stage due to sufficient nitrogen and water, which is indicated by the highest δ15N values and nitrogen contents (i.e., −1.7 ‰ and 4.5 %), and the relatively low δ13C values (i.e., −29.4 ‰), leading to accelerated vegetation growth. This study highlights not only the importance of analyzing plant diversity, but also the material cycles, especially water use efficiency, and nitrogen dynamics, to understanding forest recovery. These findings can support effective conservation and sustainable development of subtropical forest ecosystems.