Global biodiversity scenarios for the year 2100

Freshwater fish community assessment using eDNA metabarcoding vs. capture-based methods: Differences in efficiency and resolution coupled to habitat and ecology

Environmental DNA (eDNA) metabarcoding has revolutionized ecological and environmental research by describing communities without relying on direct observations, making it a powerful, non-invasive, and cost-effective tool in biodiversity monitoring. However, the adoption of eDNA as a standard protocol in long-term monitoring programs, which have traditionally relied on capture-based methods, presents challenges in terms of data comparability. Here, we compared freshwater fish communities assessed through eDNA metabarcoding and electrofishing, across 35 sampling sites in the lower Tagus River basin, Portugal. For the majority of species or species-groups analysed individually (13 out of 17), a significant correspondence was observed between electrofishing and eDNA metabarcoding detections. A weaker correspondence was found between the number of specimens captured by electrofishing with the number of eDNA metabarcoding reads, with seven out of 13 taxa showing significant relationships. Species richness estimates based on the two methods were very similar at the basin level. The methods yielded significantly different species compositions, although these differences were driven by samples collected in the Tagus main channel, which is wider and has higher flow rates than tributaries. Benthic and shoreline fish communities showed similar species composition in the two methods, but this was not the case for pelagic communities, probably due to the higher water turnover of the pelagic zone and electrofishing inefficiency. Our results highlight the high potential of eDNA metabarcoding as a complementary method to electrofishing for freshwater fish monitoring, though further validation is needed to assess biases related to site-specific hydrological conditions and the ecology of the target species.

Climate-related drivers of migratory bird health in the south-central USA

Migratory birds are species of concern that play important ecological roles while also supporting recreational opportunities for the hunting and birdwatching public. Direct and indirect effects of climate variability, extremes, and change on migratory bird health manifest at the individual, population, species, and community levels. This review focuses on the effects of climate on migratory birds that spend part of their life cycles in the south-central USA. Although gaps in knowledge remain, prior studies provide a solid foundation to understand how climate affects migratory birds to inform management priorities and actions.

Predation success of declining long-snouted seahorse (Hippocampus guttulatus) population under habitat shifts

Seahorse populations are facing significant declines worldwide, often associated to illegal trade and habitat loss or fragmentation. Emergent habitat shifts towards invasive seaweeds, facilitated by global warming, can also be at play, having still unknown effects on seahorse ecology. Particularly, indirect impacts on seahorse populations via altered predation success remains largely unexplored. Here, we conducted mesocosm experiments to investigate differences in the prey capture success of the long-snouted seahorse (Hippocampus guttulatus) among native habitats (i.e. seagrass meadows and unvegetated sediments) and non-native Caulerpa prolifera meadows when offered different preys (amphipods and shrimps), at low or high prey availability, and under low or high habitat complexity. Great plasticity of H. guttulatus to all habitats was revealed, as habitat type did not significantly affect the capture success. Instead, capture success depends on prey identity and availability regardless of the habitat type, as well as on habitat complexity. Seahorse capture success was higher under high prey availability, as well as when predating on amphipods that were offered together with shrimps. High habitat complexity of both vegetated habitats enhanced by double the capture success, whereas an opposite effect of similar magnitude was found for more complex unvegetated habitats. This indicates that vegetation complexity, regardless their native or invasive nature, reduces prey awareness to predator, whereas small structures in unvegetated habitats provide refuge for preys but not seahorse camouflage. We found no evidence that shifts from native habitats to invasive C. prolifera negatively impact H. guttulatus capture success, but further research on other aspects of its feeding ecology is still necessary.

Local tree cover predicts mosquito species richness and disease vector presence in a tropical countryside landscape

Context

Land use change and deforestation drive both biodiversity loss and zoonotic disease transmission in tropical countrysides. For mosquito communities that can include disease vectors, forest loss has been linked to reduced biodiversity and increased vector presence. The spatial scales at which land use and tree cover shape mosquito communities present a knowledge gap relevant to both biodiversity and public health.

Objectives

We investigated the responses of mosquito species richness and Aedes albopictus disease vector presence to land use and to tree cover surrounding survey sites at different spatial scales. We also investigated species compositional turnover across land uses and along environmental gradients.

Methods

We paired a field survey of mosquito communities in agricultural, residential, and forested lands in rural southern Costa Rica with remotely sensed tree cover data. We compared mosquito richness and vector presence responses to tree cover measured across scales from 30 to 1000 m, and across land uses. We analyzed mosquito community compositional turnover between land uses and along environmental gradients of tree cover, temperature, elevation, and geographic distance.

Results

Tree cover was both positively correlated with mosquito species richness and negatively correlated with the presence of the common invasive dengue vector Ae. albopictus at small spatial scales of 90-250 m. Land use predicted community composition and Ae. albopictus presence.

Conclusions

The results suggest that local tree cover preservation and expansion can support mosquito species richness and reduce disease vector presence. The identified spatial range at which tree cover shapes mosquito communities can inform the development of land management practices to protect both ecosystem and public health.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10980-025-02105-0.

Impacts of land use change on habitat quality and its driving mechanisms in the lake basin of Central Yunnan

The five major plateau lake basins in central Yunnan are densely populated areas with high land use intensity. The spatiotemporal changes in land use significantly affect the ecological environment quality of the entire basin. This research utilized land use data from 1990 to 2020, and the InVEST model to analyze land use change and its impact on habitat quality in the basin. The results indicated that cropland has been the predominant land use type during this period but has steadily decreased, while the areas of forest land and impervious surfaces increased. Additionally, the intensity of conversion between different land types was significant, primarily involving the transformation of cropland into other land types. The overall habitat quality improved, predominantly characterized by high and relatively low grades of habitat quality. Regions experiencing improved habitat quality outnumber those degradation, and the spatial distribution of habitat quality showed "high at the edges, low in the lakeside areas" around each lake. Land use change was the most dominant factor influencing the distribution of habitat quality within the lake basin, with 91.89% of the contribution rate to habitat quality improvement attributed to transitions from cropland to forest and grassland, while 94.12% of the contribution rate to habitat quality degradation was due to the expansion of impervious surfaces and the encroachment of cropland into other ecological land uses. Therefore, the findings of this study provide important reference for future land use planning and ecological environmental protection in the lake basin of central Yunnan.

Altitudinal Variations in Coniferous Vegetation and Soil Carbon Storage in Kalam Temperate Forest, Pakistan

Understanding the complex interplay among altitudinal gradients, tree species diversity, structural attributes, and soil carbon (C) is critical for effective coniferous forest management and climate change mitigation. This study addresses a knowledge gap by investigating the effects of altitudinal gradient on coniferous tree diversity, biomass, carbon stock, regeneration, and soil organic carbon storage (SOCs) in the understudied temperate forests of the Hindu-Kush Kalam Valley. Using 120 sample plots 20 × 20 m (400 m2) each via a field inventory approach across five altitudinal gradients [E1 (2000-2200 m)-E5 (2801-3000 m)], we comprehensively analyzed tree structure, composition, and SOCs. A total of four coniferous tree species and 2172 individuals were investigated for this study. Our findings reveal that elevation indirectly influences species diversity, SOCs, and forest regeneration. Notably, tree height has a positive relationship with altitudinal gradients, while tree carbon stock exhibits an inverse relationship. Forest disturbance was high in the middle elevation gradients E2-E4, with high deforestation rate at E1 and E2. Cedrus deodara, the dominant species, showed the highest deforestation rate at lower elevations (R2 = 0.72; p < 0.05) and regeneration ability (R2 = 0.77; p < 0.05), which declined with increasing elevation. Middle elevations had the highest litter carbon stock and SOCs values emphasizing the critical role of elevation gradients in carbon sink and species distribution. The regeneration status and number of trees per ha in Kalam Valley forests showed a significant decline with increasing elevation (p < 0.05), with Cedrus deodara recording the highest regeneration rate at E1 and Abies pindrow the lowest at E5. The PCA revealed that altitudinal gradients factor dominate variability via PCA1, while the Shannon and Simpson Indices drives PCA2, highlighting ecological diversity's independent role in shaping distinct yet complementary vegetative and ecological perspectives. This study reveals how altitudinal gradients shape forest structure and carbon sequestration, offering critical insights for biodiversity conservation and climate-resilient forest management.

Robotic monitoring of European habitats: a labeled dataset for plant detection in Annex I habitats of Italy

The present data descriptor presents a dataset designed for the detection of plant species in various habitats of the European Union. This dataset is based on images captured using multiple different hardware including quadrupedal robot ANYmal C, referring to ecologically important species to assess the presence and conservation status in Annex I habitats 2110, 2120, 6210*, 8110, 8120, and 9210*. Plant scientists and robotic engineers gathered the data in key Italian protected areas and labeled it using YOLOtxt format. Researchers in vegetation science, habitat monitoring, robotics, machine learning, and biodiversity conservation can access the dataset through Zenodo. The ultimate goal of this collaborative effort was to create a dataset that can be used to train artificial intelligence models to assess parameters that enable robotic habitat monitoring. The availability of this dataset may enhance future studies and conservation initiatives for Annex I habitats inside and outside the Natura 2000 network. The dataset and the methods used to obtain it are fully described, highlighting the significance of interdisciplinary cooperation in habitat monitoring.

New insights on the Rickettsia-tick-wild bird associations in the Western Amazon, Brazil

Several studies have highlighted the importance of balancing wildlife and plant life to mitigate the spread of ticks and their pathogenic microorganisms. This balance is essential for preserving the health of wildlife, domestic animals, and, consequently, human populations. However, human activities, characterized by habitat destruction and fragmentation, have brought humans and domestic animals closer to wild bird populations, which act as dispersers of ticks of public health importance. In light of these challenges, this study aimed to determine the frequency of occurrence and abundance of tick species in wild birds in the upland forests of the southwestern Brazilian Amazon. Data were collected in two municipalities: Rio Branco (four urban forest fragments) and Manoel Urbano (an area of continuous forest in the Parque Estadual Chandless), both located in the state of Acre, Brazil. Birds were captured between May and September 2021 using 10 mist nets placed in five transects of each study area, resulting in a sampling effort of 1210 net hours. Captured birds were thoroughly inspected for tick infestation, and when found, they were removed using forceps. These ticks were identified using a stereomicroscope and specific taxonomic keys, as well as molecular analysis by PCR. We captured 315 birds, of which 95 (30.15 %) were infested with ticks in the larval and nymph stages. A total of 368 ticks belonging to the genus Amblyomma were collected. This included species such as Amblyomma coelebs, Amblyomma geayi, Amblyomma humerale, Amblyomma longirostre, Amblyomma nodosum, and Amblyomma maculatum sensu lato (s.l.). These results highlight 13 new associations between wild birds and ticks of the genus Amblyomma and reveal, for the first time, the presence of Amblyomma maculatum s.l. and rickettsiae from the Spotted Fever Group. These findings expand the knowledge of the epidemiology of ticks and rickettsial agents of public health importance in the region.

Biodiversity-induced opposing shifts of tipping points in mutualistic ecological networks

While biodiversity is recognized as crucial for ecosystem stability, the mechanisms governing its dual role in collapse and restoration dynamics remain unclear. By analyzing ten empirical plant-pollinator mutualistic networks, we uncover a biodiversity paradox: increased biodiversity lowers the collapse threshold while enhancing restoration potential. This counterintuitive phenomenon is quantitatively linked to a significant negative correlation between biodiversity levels and hysteresis loop width. To understand this paradox, we develop a refined degree-weighted mean-field framework, reducing high-dimensional dynamics to a tractable two-dimensional system. By integrating potential landscape theory from nonequilibrium statistical mechanics, we uncover the physical basis of biodiversity-driven threshold shifts. Systematic modulation of mutualistic interaction degrees across stochastic networks further confirms the universal regulatory role of reduced biodiversity in collapse-restoration tipping points. Our findings provide a quantitative framework for predicting ecosystem resilience and optimizing restoration strategies across biodiversity gradients.

Prioritizing the Risk of Multiple Invasive Species in the Semiarid Rangelands of Iran: An Ecological Approach to Multicriteria Decision-Making

Invasive plants pose a threat to production sustainability due to their detrimental effects on soil, food cycles, and hydrology. This study aimed to identify and analyze the effects of five invasive plant species on the rangelands of western Isfahan province, Iran. A random-systematic sampling of vegetation cover and soil was conducted at four rangeland sites, and mean soil characteristics were compared using one-way analysis of variance and Tukey's test. Parametric principal component analysis (PCA) and nonparametric multidimensional scaling (NMDS) analysis in CANOCO and PATN software were used to investigate the relationship between environmental factors and vegetation cover. Cluster analysis was employed for habitat grouping, and the Analytic Hierarchy Process (AHP) was utilized to analyze the risk of invasive plants. The analysis involved three main criteria, eight subcriteria, and five options. The compatibility ratio of each criterion was calculated using Expert Choice software to assess the accuracy of criteria weighting. Parametric ordination revealed significant correlations between the first and second principal components and mean annual precipitation, mean annual temperature, altitude, slope, nitrogen, and calcium. NMDS analysis revealed significant correlations between plant species and seven environmental variables in a three-dimensional ordination space (p < 0.05). Among the target species, Eryngium billardieri showed a positive correlation with rainfall, altitude, slope, calcium, nitrogen, and a negative correlation with mean annual temperature, rock, and gravel. However, the relationship of other species with environmental factors was not significant. Notably, Cousinia bachtiarica, Eryngium billardieri, Phlomis persica, Euphorbia decipiense, and Poa bulbosa exhibited the most destructive effects, respectively. The study results can inform targeted efforts to protect rangeland ecosystems against invasive plants. Furthermore, the study method is applicable for assessing the risk of other plant species in semiarid ecosystems.

Ecologically informed solar enables a sustainable energy transition in US croplands

United States (US) croplands are ideal recipient environments for solar photovoltaic (PV) energy because they are flat and have a high solar resource. Perceived threats of solar to agriculture have led some stakeholders to suggest that croplands be exclusively used to produce food. However, 12 million hectares of US croplands, an area about the size of New York State, are already dedicated to corn grown for ethanol (i.e., biofuel), an energy product that requires significantly more land than solar PV per unit energy. Ecosystem service benefits of an ecologically informed approach to solar development (i.e., ecovoltaics), coupled with significant land-use advantages over corn ethanol, make solar an attractive solution for a sustainable energy transition in croplands. Here, we evaluated how the conversion of a small fraction of corn-ethanol croplands into ecovoltaic solar facilities might improve land-use efficiency of energy generation, enhance ecosystem services, and provide landscape diversification. Through spatial analyses, we determined that converting just 3.2% of land currently used for corn ethanol would increase the share of utility-scale solar energy in the US from 3.9 to 13%. We also identified target locations where strategic conversion of corn ethanol to solar PV colocated with perennial vegetation could filter excess nutrients transported from adjacent farm runoff, diversify and connect agricultural landscapes, and provide local wildlife habitat. In contrast to the common perception of land-use competition and land scarcity in the energy transition, our findings highlight benefits of colocated energy landscapes that integrate fundamental principles of energy development and sustainable agroecosystems.

Snow Leopard habitat vulnerability assessment under climate change and connectivity corridor in Xinjiang Uygur autonomous region, China

Climate change is recognized as one of the greatest challenges to global biodiversity. The endangered snow leopard (Panthera uncia), an apex predator in high-altitude mountain ecosystems, serves as an important indicator of ecological health. Understanding the impacts of climate change on snow leopard distribution patterns is essential for developing effective conservation strategies. Based on the BIOMOD2 model, this study assesses the current distribution of suitable habitats and project future changes under various climate scenarios, as well as evaluates the protection gap and corridor construction in Xinjiang Uygur Autonomous Region, China. The results indicated the total area of suitable habitat for snow leopard in Xinjiang is approximately 686,200 km2 under the current climate conditions. The area of suitable habitat remains relatively stable or slightly increases under low emissions scenarios, while predictions show a gradual decline under moderate and high emissions scenarios. Currently, suitable habitats are fragmented, with low connectivity among patches, posing threats to the snow leopard population. Vulnerable habitats are primarily located in the Altai, northwestern Junggar Basin, and the central Tianshan Mountains. Potential future suitable areas are projected emerge in the Kunlun Mountains. It is suggested that greater focus be placed on unprotected climate refugia, enhancing the connectivity of habitat corridors, fostering cross-border cooperation, and implementing long-term monitoring efforts. This study provides valuable insights for conservation strategies aimed at mitigating the impacts of climate change on snow leopard populations in Xinjiang, China.

Revision of nitrogen critical loads for Natura 2000 Habitat types in The Netherlands

Critical loads for atmospheric deposition of nitrogen are increasingly used as official standards in national legislation. This requires unique values (i.e., not ranges) based on state-of-the-art scientific knowledge. In The Netherlands such values have been derived in the past by combining the empirical critical load ranges for Europe with local simulated values. We describe this method in detail, resulting in a unique critical load value for each Habitat type of the European Habitats Directive that occurs in The Netherlands. As the empirical values have been adjusted downward several times in recent decades while the simulation model was not updated since 2004, there is an increasing gap between the empirical and the simulated values. Here we use the new, empirical response model DOREN to bridge this gap, but we argue that a new simulation model is urgently needed. Our results show critical load exceedance in 61 % of the total area of nitrogen-sensitive Habitat types in The Netherlands. The most threatened Habitat types are oligotrophic freshwater, bog, species-rich grassland, and beech forest; either because they have a low critical load, or because they occur in areas where nitrogen deposition is high.

Global extent and change in human modification of terrestrial ecosystems from 1990 to 2022

Habitat loss and degradation associated with industrial development is the primary threat and dominant driver of biodiversity loss globally. Spatially-explicit datasets that estimate human pressures are essential to understand the extent and rate of anthropogenic impacts on ecosystems and are critical to inform conservation commitments and efforts under the Global Biodiversity Framework. We leveraged the human modification framework to generate comprehensive, consistent, detailed, robust, temporal, and contemporary datasets to map cumulative and individual threats associated with industrial human activities to terrestrial biodiversity and ecosystems from 1990 to 2022. In ~2022, 43% of terrestrial lands had very low levels of modification, while 27%, 20%, and 10% had low, moderate, and high modification, respectively. Nearly 2/3 of biomes and 1/2 of ecoregions currently are moderately-modified, and 24% of terrestrial ecosystems (31 M km2) experienced increased modification from 1990 to 2020. About 29% of countries and 31% of ecoregions might also be particularly vulnerable to biodiversity loss given their above-average increased modification and less than 30% protection.

Family forest owner's perspectives on headwater streams in boreal forests: Motivations, values, and conservation actions

Boreal headwater streams are vital for forest biodiversity and larger water bodies but face challenges from forest management. Understanding forest owner's views is key for effective water management. Our research surveys family forest owners to explore: (1) their perception of stream value, (2) factors driving their willingness to protect streams, and (3) if motivations for forest ownership vary by residence. Most owners are motivated by recreation. Those living far from their forests prioritize landscape, heritage, and biodiversity more than nearby residents. While owners recognize the importance of biodiversity and water protection, this does not always influence their management choices. Owners who are familiar with the link between forest management and stream health are more willing to protect streams from logging impacts. These findings highlight the need for better advice and policies for forest owners on managing water quality and biodiversity.

Impacts of elevated temperature and CO2 concentration on carbon metabolism in an endangered carnation: Consequences for biomass allocation and flowering

One of the greatest threats to plant function and fitness is global warming, characterised by a combination of increased atmospheric CO2 concentrations and temperatures. However, their effects on plant physiology, growth, and reproduction remain unclear, particularly for rare species that support vulnerable ecosystem functions. Here, we investigated these effects on leaf and whole-plant functional traits of the rare endangered C3 species Dianthus inoxianus. Mature plants were grown for 18 weeks in controlled-environment chambers under four environmental scenarios that combined day/night air temperatures (ambient: 25/20 °C or elevated: 29/24 °C) with CO2 concentrations (400 ppm or 700 ppm). Under elevated temperature, D. inoxianus exhibited impaired photosynthetic capacity but also employed an avoidance strategy by prioritising accelerated reproduction (earlier flowering) and biomass allocation to roots for future resprouting. Elevated CO2 induced photosynthesis acclimation and biochemical constraints, preventing growth enhancement, but also mitigated the loss of stomatal functionality and carboxylation capacity loss caused by elevated temperature. Although plants sustained gas exchange under combined elevated CO2 and temperature, assimilation rates decreased. Such a decline, linked to reduced photoprotection capacity and photosystem performance, was accompanied by an advanced onset of flowering and reduced flower production. These changes suggest that the vulnerability of D. inoxianus might increase under climate change, with additional stressors potentially exacerbating photoinhibition. Our findings offer critical insights into the complex relationships between threatened species and their environment, underscoring the need for preventive conservation measures for D. inoxianus to address the challenges posed by more extreme or prolonged environmental stresses.

Shedding light on biodiversity: reviewing existing knowledge and exploring hypothesised impacts of agrophotovoltaics

The growing demand for energy and the shift towards green energy solutions have led to the conversion of open spaces and agricultural fields into photovoltaic (PV) power plants, exacerbating the "food-energy-environment" trilemma. Agrophotovoltaics (APVs), a dual-use system combining agriculture and energy production on the same land, presents a potential solution to this challenge. While the environmental impacts of ground-mounted utility-scale PV (USPV) power plants and the effects of APV systems on agricultural yields have been extensively studied and reviewed, the implications for wildlife and biodiversity remain largely unexplored. This knowledge gap is pressing, given the accelerated global adoption of APV systems and the urgency of understanding their broader ecological consequences. In this concise review, we synthesise existing literature on the impacts of USPV installations on biodiversity and the effects of APV on crop production. Building on these foundations, we propose novel hypotheses concerning the potential pathways and mechanisms through which APV systems may influence biodiversity. We explore the complex interactions between agroecosystems and natural ecosystems, examining both direct and indirect effects. Our review culminates in a set of key research questions designed to guide future studies on the biodiversity outcomes of APV deployment. Future research should comprehensively address factors such as habitat type, climate, spatial scale, technology, and agricultural practices, as well as the overarching impacts of climate change. By highlighting the importance of these variables, we aim to facilitate a nuanced understanding of how APV systems can either support or undermine biodiversity. This work not only underscores the critical need for empirical studies in this emerging field but also sets the stage for more informed and sustainable implementation of APV technologies.

Weak effect of temperature fluctuations on the invasion of Raphidiopsis raciborskii (Cyanobacteria) in experimental plankton microcosms

Biological invasions are a major threat for many aquatic ecosystems. In contrast to higher plants and animals, microbial invasions are less obvious and more difficult to detect. One of the most prominent microbial invaders is the cyanobacterium Raphidiopsis raciborskii. To better understand the environmental conditions favoring its invasion success, we studied invasion under three different temperature regimes (one constant and two variable) in experimental plankton communities by invader addition experiments. To account for intraspecific variation, we tested four different strains of R. raciborskii and the mixture of them. Invasion success of R. raciborskii was higher under constant temperature conditions than under fluctuations suggesting that the resident species responded faster to the environmental changes than the invaders. We observed a clear strain-specific effect, demonstrating that strain identity is an important determinant of invasion success. The interaction of temperature fluctuations and strain identity indicates that, among the tested strains, the response to the temperature regimes varied. The mixture of all four strains did not perform better than the best single strain showing no sign of a positive genetic diversity effect. In our experiment, environmental fluctuations did not widen a window of opportunity for the invasion of R. raciborskii.

Impact of climate change on the distribution range and niche dynamics of Himalayan Aconites: a highly important medicinal plant species of the higher Himalayan range

Alpine vegetation found in mountainous areas is reportedly sensitive to the expected heat caused by climate change. Aconitum species, which is an indicator species for monitoring the signal of climate change, also falls under this range. Aconitum heterophyllum and Aconitum balfourii thrive among diverse plant communities and serve as key species marking the onset of the alpine range. The current study uses the maximum entropy (MaxEnt) program to estimate the geographic distribution of Aconitum taxa for the present and the future (RCPs 2.6-8.5 encompassing 2050). The final model that was obtained had an area under the ROC curve AUC of 0.95, demonstrating the model's resilience. Species distribution modeling (SDM) toolbox was used to evaluate changes in the habitat appropriateness, area expansion, and contraction based on the MaxEnt model. Future forecasts indicate that the Eastern Himalayas would be a more favorable environment for both Aconitum species when compared to the Western Himalayas. According to our best knowledge, this package was used for the first time in the study to evaluate the dynamics of the climatic niches of two critically endangered Aconitum species for the Indian Himalayan ranges. The climatic niche of this alpine species is expected to shift in the future due to alterations in its habitat regions. The Aconitum niche is in danger under scenarios of future climate change, according to the AUC and Jackknife values. The findings of the current study contribute substantially to understanding how climate change affects the Himalayas and have broad implications for the development of scientifically sound adaptation and mitigation measures, as the major factors influencing its distribution are altitude, snow cover, chilling hours for both seeds and tubers, temperature, and rainfall patterns.

Changes in community composition and functional diversity of European bats under climate change

Climate change is predicted to drive geographical range shifts that will result in changes in species diversity and functional composition and have potential repercussions for ecosystem functioning. However, the effect of these changes on species composition and functional diversity (FD) remains unclear, especially for mammals, specifically bats. We used species distribution models and a comprehensive ecological and morphometrical trait database to estimate how projected future climate and land-use changes could influence the distribution, composition, and FD of the European bat community. Future bat assemblages were predicted to undergo substantial shifts in geographic range and trait structure. Range suitability decreased substantially in southern Europe and increased in northern latitudes. Our findings highlight the potential for climate change to drive shifts in bat FD, which has implications for ecosystem function and resilience at a continental scale. It is important to incorporate FD in conservation strategies. These efforts should target species with key functional traits predicted to be lost and areas expected to experience losses in FD. Conservation strategies should include habitat and roost protection, enhancing landscape connectivity, and international monitoring to preserve bat populations and their ecosystem services.

Soil Microbial Co-Occurrence Networks Across Climate and Land Use Gradient in Southern Italy

Despite extensive research on microbiota across land use gradients, it remains unclear if microbial co-occurrence relationships exhibit consistent patterns. Here, we assessed microbial co-occurrence networks of seven natural ecosystems-Quercus ilex forest, Fagus sylvatica forest, Abies alba forest, Mediterranean and mountain grasslands, and subalpine and Mediterranean shrublands-and five agroecosystems, including vineyards, horticulture, greenhouse, a polluted agricultural system, and an arid greenhouse. Soil chemistry, such as pH, organic carbon and total nitrogen, was characterised, and soil microbiota were profiled using high-throughput sequencing from 242 soil samples. Our results revealed that mountain grasslands had the highest organic carbon (86.4 g/kg), while the arid greenhouse had the lowest (6.1 g/kg). Mediterranean grasslands had the lowest pH of 5.79, and vineyards had the highest electrical conductivity of 0.901 dS/m. Notably, natural ecosystem networks exhibited greater modularity, with protected horticulture showing exceptionally the highest (0.937), while intensive agriculture within agroecosystems had a significantly lower modularity of 0.282. Modularity and the number of modules were positively correlated with soil P2O5, while network diameter, path length and clustering coefficient were correlated with soil pH. Additionally, edges and nodes number, average degree and microbial diversity were positively associated with organic carbon and total nitrogen. These findings highlight that natural ecosystems foster more complex and resilient microbial networks, underscoring sustainable land management's importance to preserve soil health and microbial diversity.

Longitudinal reconfiguration of multifaceted fish α and β diversity triggered by non-native species invasion in tropic rivers of Hainan Island

Human-mediated fish invasions have reconfigured the native fish faunas throughout the freshwater ecosystems worldwide. Beyond the well-documented homogenization reported in temperate basins, our knowledge on how multifaceted biodiversity response to fish invasions in tropic rivers remains poorly understood. It is also hanged in doubt that how fish invasions modify the longitudinal patterns of fish faunas under the concept of river continuum. Here, we applied one-way permutational multivariate analysis of variance to test how fish invasion influenced the longitudinal patterns of multifaceted α and β diversity of fish assemblages in three largest rivers of Hainan Island, China. Meanwhile, we employed multiple regression analysis to examine the relationships between the invasion degree and multiple α diversity indices as well as functional traits of native fishes. We found non-significant longitudinal variations for all multifaceted α diversity for native fish assemblages. However, our results demonstrated significantly longitudinal variations for multifaceted overall β diversity and its turnover components to the upstream-downstream gradient. Considering the consequence of non-native species invasion, we recorded tough homogenization in all the multifaceted aspects, as all the overall β diversity and its turnover components were concurrently significantly decreased after invasions. In comparation with upper reaches, the middle-lower reaches exhibited more significant homogeneous patterns incurred by invasions. In terms of biotic acceptance/resistance hypothesis, we found native fish faunas with higher richness, evenness and trophic level tented to resistant invaders, whereas with even phylogenetic compositions and late maturation showed acceptance to invasions.

Environmental Factors Influencing the Establishment of the Invasive Australian Redclaw Crayfish (Cherax quadricarinatus) in a Biosphere Reserve on the Central Mexican Plateau

Crustaceans are among the most successful taxonomic groups in invasions worldwide. Humans can facilitate these invasions through introductions and disturbances in habitats. The Australian redclaw crayfish (Cherax quadricarinatus) is an invasive species with significant global ecosystem impacts. This species inhabits the Sierra Gorda Biosphere Reserve, in the Central Mexican Plateau. We hypothesize that environmental degradation facilitates the establishment and expansion of invasive crayfish. Seven sites along the Santa María River, within the reserve buffer zone, were assessed for seven months in 2023. We analyzed the abundance and density of the Australian redclaw crayfish in correlation with the environmental quality of the habitat. The results confirm that the establishment and spread of crayfish populations are related to water quality degradation and habitat alteration. The associated variables include increased total dissolved solids, greater substrate embedment, and degraded conditions on stream banks. Furthermore, the inverse relationship between the abundance of Australian redclaw crayfish and macroinvertebrate richness reinforces the hypothesis that more diverse native communities reduce the success of invaders. This study highlights the urgent need to implement management strategies focused on habitat restoration and the control of reproductive populations through the extirpation of mature individuals as critical measures for controlling the establishment and expansion of the invasive Australian redclaw crayfish.

Global scale high-resolution habitat suitability modeling of avifauna providing pollination service (sunbirds, Nectariniidae)

Avian species provide important ecosystem services such as nutrient cycling, seed dispersal, meat provision, pest control, scavenging, and pollination. Currently, the populations of avian pollinators are declining due to climate change and human impact, and it is crucial to identify species-rich areas for their conservation. Sunbirds (Nectariniidae) are important vertebrate pollinators with a wide distribution that include Africa, Asia and Australasia. Here, we assembled distribution records of sunbird species and applied a maximum entropy approach to model sunbird habitat suitability in the world. We also quantified sunbirds composition similarity among the terrestrial biomes. We found that sunbird habitat suitability reached a peak in Southeast Asia, and in western and central parts of the African continent. Sunbird richness was highest in the Tropical and Subtropical Moist Broadleaf Forests biome. Solar Radiation Index (SRI), precipitation of the warmest quarter, and human footprint index were the most important predictors of sunbirds global habitat suitability. Geographic regions identified to have the highest suitability and richness for sunbirds have high priority for conservation of this unique group of avian pollinators and the ecological services they provide.

Abiotic variables drive different aspects of fish community trait variation and species richness across the continental United States

Intraspecific trait variation (ITV) is an increasingly important aspect of biodiversity and can provide a more complete perspective on how abiotic and biotic processes affect individuals, species' niches and ultimately community-level structure than traditional uses of trait means. Body size serves as a proxy for a suite of traits that govern species' niches. Distributions of co-occurring species body sizes can inform niche overlap, relate to species richness and uncover mechanistic drivers of diversity. We leveraged individual-level body size (length) in freshwater fishes and environmental data from the National Ecological Observatory Network (NEON) for 17 lakes and streams in the contiguous United States to explore how abiotic and biotic factors influence fish species richness and trait distributions of body size. We calculated key abiotic (climate, productivity, land use) and biotic (phylogenetic diversity, trait diversity, community-level overlap of trait probability densities) variables for each site to test hypotheses about drivers of ITV in body size and fish diversity. Abiotic variables were consistently important in explaining variation in fish body size and species richness across sites. In particular, productivity (as chlorophyll) was a key variable in explaining variation in body size trait richness, evenness and divergence, as well as species richness. This study yields new insights into continental-scale patterns of freshwater fishes, possible only by leveraging the paired high frequency, in situ abiotic data and individual-level traits collected by NEON.

Effects of short-term thermal stress on functional response and interspecific interaction of whitefly parasitoids

The functional response of a biocontrol agent, as well as its interactions with co-occurring species under thermal stress, are 2 crucial factors in evaluating its ability to control arthropod pests in the context of climate warming. Encarsia formosa (Gahan) (Hymenoptera: Aphelinidae) is one of the most extensively utilized biological control agents for the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). In the present study, we evaluated the effects of short-term heat stress on the functional response and host control efficacy of En. formosa, as well as the interspecific interactions between this parasitoid and the co-occurring parasitoid Eretmocerus hayati (Zolnerowich and Rose) (Hymenoptera: Aphelinidae). At all experimental temperatures, type II functional responses of En. formosa were observed in both parasitism and host feeding. The type of functional response remained unaffected by experimental temperature. Roger's model was utilized to fit the data. Based on the 95% confidence interval, pairwise comparisons of searching rate (a) and handling time (Th) across temperature regimes yielded no significant differences. In most instances, the increased temperatures did not affect the host control efficacy of En. formosa. The coexistence of En. formosa and Er. hayati exhibited a negative impact on En. formosa's parasitism but a positive effect on that of Er. hayati across all temperature regimes. These findings provide valuable knowledge regarding the functional dynamics of En. formosa under climate warming and underscore the importance of understanding interspecific relationships among biocontrol agents to effectively optimize pest management strategies.

Forb diversity globally is harmed by nutrient enrichment but can be rescued by large mammalian herbivory

Forbs ("wildflowers") are important contributors to grassland biodiversity but are vulnerable to environmental changes. In a factorial experiment at 94 sites on 6 continents, we test the global generality of several broad predictions: (1) Forb cover and richness decline under nutrient enrichment, particularly nitrogen enrichment. (2) Forb cover and richness increase under herbivory by large mammals. (3) Forb richness and cover are less affected by nutrient enrichment and herbivory in more arid climates, because water limitation reduces the impacts of competition with grasses. (4) Forb families will respond differently to nutrient enrichment and mammalian herbivory due to differences in nutrient requirements. We find strong evidence for the first, partial support for the second, no support for the third, and support for the fourth prediction. Our results underscore that anthropogenic nitrogen addition is a major threat to grassland forbs, but grazing under high herbivore intensity can offset these nutrient effects.

Shaping beta diversity in arid landscape through native plant species contributions: synergy of climate, soil, and species traits

Understanding how species traits, climate aridity, and soil resources interact to influence beta diversity is critical for predicting changes in plant community composition. This study aims to investigate how these interactions shape species contributions to spatial turnover and beta diversity, focusing on the unique dryland ecosystems of the Saint Katherine Protectorate (SKP) in Egypt. To address this, we analyzed data from 84 vegetation plots, considering the direct and indirect effects of climatic aridity, soil resources, and species traits (e.g., plant height, leaf production, specific leaf area), as well as the relative abundance of C3 plants and phylogenetic diversity on species contribution to beta diversity (SCBDeff). Using Generalized Linear Models (GLMs) and Structural Equation Modelling (SEMs), the results revealed complex indirect effects of aridity and soil resources on SCBDeff mediated by plant traits. SCBDeff was positively influenced by climatic aridity, particularly in species with greater phylogenetic distance, taller plants, high leaf production, and a higher relative abundance of C3 plants. Conversely, specific leaf area (SLA) had a negative effect. Phylogenetic diversity emerged as a significant driver of beta diversity, with distantly related species contributing more due to functional differentiation and niche partitioning. The findings emphasize the critical role of species traits and environmental conditions in shaping beta diversity. These insights can inform conservation strategies aimed at enhancing ecosystem stability under shifting climatic conditions, particularly in dryland environments where species adaptive traits play a pivotal role.

Differential roles of deterministic and stochastic processes in structuring soil bacterial ecotypes across terrestrial ecosystems

Soil bacteria are vital to ecosystem resilience and resistance, yet ecological attributes and the drivers governing their composition and distribution, especially for taxa varying in ecological traits and inhabiting different ecosystems, are not fully understood. Here, we analyzed a large-scale bacterial community and environmental dataset of 622 soil samples systematically collected by us from six major terrestrial ecosystems across the United States. We show that soil bacterial diversity and composition significantly differ among ecotypes and ecosystems, partially determined by a few universal abiotic factors (e.g., soil pH, calcium, and aluminum) and several ecotype- or ecosystem-specific ecological drivers. Co-occurrence network analysis suggests that rare taxa have stronger ecological relevance to the community than abundant taxa. Ecological models revealed that deterministic processes shape assembly of abundant taxa and generalists, while stochastic processes played a greater role in rare taxa and specialists. Also, bacterial communities in the shrubland ecosystem appear to be more sensitive to environmental changes than other ecosystems, evidenced by the lowest diversity, least connected community network, and strongest local environmental selection driven by surrounding land use. Overall, this study reveals ecological mechanisms underlying the bacterial biogeography in terrestrial ecosystems nationwide and highlights the need to preserve rare biosphere and shrubland ecosystems amid environmental disturbance.

Comparative diversity of aquatic plants in three Central European regions

Freshwaters are among the most threatened ecosystems globally, with biodiversity declining at far greater rates than the biodiversity of the most affected terrestrial ecosystems. There is an urgent need for accurate information on spatial patterns of freshwater biodiversity, a first step in effective conservation planning and management of these ecosystems. We explored patterns of aquatic macrophyte diversity in four waterbody types, rivers, streams, ponds and ditches, across three Central European regions. By analyzing local (α), among-site (β) and regional (γ) diversity, we assessed the roles of these ecosystems as biodiversity hotspots, particularly for red-listed species. Sampling 220 sites across Slovakia and Slovenia, we recorded 113 macrophyte taxa (31% of which were red-listed), with ponds and ditches consistently supporting higher α and γ diversity than running waters. β diversity was primarily driven by species turnover, with ponds displaying high heterogeneity linked to environmental variability. Our findings highlight the conservation value of artificial habitats like ditches and ponds, harbouring significant macrophyte diversity, including unique and threatened species. These results underscore the need to prioritize small waterbodies in biodiversity conservation strategies within agricultural landscapes.

Feeding Ecology of the Critically Endangered Gobio insuyanus (Gobionidae)

Despite the critical conservation status of the endemic gudgeon Gobio insuyanus, its feeding ecology remained unstudied. This research addresses this gap by investigating the diet of G. insuyanus in the Insuyu spring-stream system of Central Anatolia (Turkey) analyzing spatial, temporal, and intraspecific variations. We compared two distinct habitats: a stable spring and its continuum, a fluctuating stream. Results indicate that G. insuyanus is an omnivore, consuming primarily detritus, Gammarids, and Diptera larvae. Feeding intensity was higher in the spring habitat, particularly in summer, possibly related to its stable temperature and lower turbidity. Dietary diversity was higher in the stream, potentially reflecting its greater habitat complexity, but decreased in both habitats in autumn, suggesting a seasonal decline in prey availability. A significant ontogenetic shift in diet was observed; mature individuals exhibited a narrower niche and preferred larger prey, probably due to increased gape size, improved foraging ability, and higher energy requirements. No significant dietary differences were found between the sexes. The results have conservation implications, emphasizing the need to maintain the integrity of both habitats. Future research incorporating fish movement data with feeding ecology will further improve our understanding and inform more targeted conservation strategies.

Do exotic invasive mammals disturb the native fauna? Spatiotemporal distribution and overlap between species in a national park of Argentina

Monitoring the invasive exotic species and their effect on native fauna is fundamental for their effective control. The objective of this research is to evaluate the spatiotemporal distribution and overlap of medium-large-sized fauna in El Palmar National Park, Argentina, to consider potential negative interactions between native and exotic species. Camera traps were distributed in 27 sites between 2017 and 2019. Spatial and temporal overlap was estimated for every pair of exotic-native taxa. With 2673 camera days, two exotic and seven native taxa were recorded. All species were distributed along the extension of the National Park but in different numbers of sites. Exotic axis deer (Axis axis) was recorded in all sites but one, and exotic wild boar (Sus scrofa) occurred at only one-third of the sites surveyed. The occurrence of native mammals ranged between 26% (Geoffroy's cat, Leopardus geoffroyi) and 67% (capybara, Hydrochoerus hydrochaeris). Spatial overlap between native and exotic species was high overall and was higher in winter when species moved over larger areas to look for limited resources. Except for greater rhea (Rhea americana), which was diurnal, all species had crepuscular or nocturnal patterns. Both exotic species had an intermediate/high overlap in their activity pattern with almost all native species, including some species with similar diets, but the hours of their maximum activities did not strictly coincide. However, the existence of differences in the exotic species' activity patterns compared to their patterns in other areas where they inhabit could indicate segregation in daily activity to relax competition.

Differences in plant responses to nitrogen addition between the central and edge populations of invasive Galinsoga quadriradiata in China

Increased nitrogen deposition significantly impacts invasive plants, leading to population differentiation due to different environmental pressures during expansion. However, various populations respond differently to elevated nitrogen levels. This study explores the responses of central and edge populations of the annual invasive plant Galinsoga quadriradiata to different levels of nitrogen addition. The results indicate that the central population has a stronger need for nitrogen, with nitrogen addition promoting the growth of its aboveground parts, reducing intraspecific competition, and increasing reproductive allocation and total biomass. Specifically, nitrogen addition provides more nutritional resources, easing resource competition among plants, reducing intraspecific competitive pressure, and allowing plants to allocate more energy to growth and reproduction, thereby enhancing their expansion potential. In contrast, the edge populations respond differently to nitrogen. Although nitrogen addition promotes the growth of their underground parts and enhances root development, the impact on aboveground parts is smaller. The enhancement of underground parts helps edge populations better adapt to barren environments, improving their survival and competitive ability in new environments, thus increasing their expansion potential. Overall, the growth impact on edge populations due to nitrogen addition is smaller, possibly indicating they have exceeded their nitrogen limit. The study demonstrates that the degree of population differentiation in invasive plants at different invasion stages is a critical factor in studying their spread potential, aiding in predicting plant invasion trends under climate change and providing theoretical support for formulating targeted management strategies.

Consumers Modulate Effects of Plant Diversity on Community Stability

Biotic complexity, encompassing both competitive interactions within trophic levels and consumptive interactions among trophic levels, plays a fundamental role in maintaining ecosystem stability. While theory and experiments have established that plant diversity enhances ecosystem stability, the role of consumers in the diversity-stability relationships remains elusive. In a decade-long grassland biodiversity experiment, we investigated how heterotrophic consumers (e.g., insects and fungi) interact with plant diversity to affect the temporal stability of plant community biomass. Plant diversity loss reduces community stability due to increased synchronisation among species but enhances the population-level stability of the remaining plant species. Reducing trophic complexity via pesticide treatments does not directly affect either community- or population-level stability but further amplifies plant species synchronisation. Our findings demonstrate that the loss of arthropod or fungal consumers can destabilise plant communities by exacerbating synchronisation, underscoring the crucial role of trophic complexity in maintaining ecological stability.

Catastrophic fish mass mortality events in Moroccan freshwater ecosystems: alarming trends and impacts on biodiversity

Fish mass mortality events (FMMEs) represent an escalating ecological crisis, significantly threatening aquatic biodiversity, particularly in North African freshwater ecosystems. Addressing a critical knowledge gap in this region, our study presents the first comprehensive assessment of FMMEs in Moroccan aquatic ecosystems, including freshwater systems and estuaries, based on meticulous monitoring from January 2020 to December 2022. During this three-year period, we documented 18 FMMEs across 16 distinct ecosystems, with a notable increase in frequency observed during the summer and autumn months. Estuaries emerged as critical hotspots for these events, exhibiting the highest frequency of FMMEs and highlighting their vulnerability to climatic and anthropogenic pressures. Our findings indicate a staggering loss of at least 7.8 million fish, with Atherina boyeri, accounted and identified as the most affected species by FMMEs. The families Cyprinidae and Mugilidae experienced the most substantial impacts, including significant biomass losses in Chelon saliens, Chelon labrosus, and Cyprinus carpio. Additionally, endemic species such as Luciobarbus maghrebensis and Luciobarbus rabatensis also faced considerable declines. These events underscore severe ecological disruptions and provide novel insights into species distribution and interactions, including the first recorded presence of Oreochromis niloticus in previously undocumented regions. This research underscores the urgent need for targeted conservation strategies and proactive interventions to mitigate the ecological and socioeconomic ramifications of FMMEs. By addressing these critical issues, we can better protect Moroccan freshwater ecosystems that are at risk of further biodiversity loss.

Anthropogenic land-use change decreases pollination and male and female fitness in terrestrial flowering plants

BACKGROUND AND AIMS

The majority of the Earth's land area is currently occupied by humans. Measuring how terrestrial plants reproduce in these pervasive environments is essential for understanding their long-term viability and their ability to adapt to changing environments.

METHODS

We conducted hierarchical and phylogenetically independent meta-analyses to assess the overall effects of anthropogenic land-use changes on pollination, and male and female fitness in terrestrial plants.

KEY RESULTS

We found negative global effects of land-use change (i.e. mainly habitat loss and fragmentation) on pollination and on female and male fitness of terrestrial flowering plants. Negative effects were stronger in plants with self-incompatibility systems and in plants pollinated by invertebrates, regardless of life form and sexual expression. Pollination and female fitness of pollination-generalist and pollination-specialist plants were similarly negatively affected by land-use change, whereas male fitness of specialist plants showed no effects.

CONCLUSIONS

Our findings indicate that angiosperm populations remaining in fragmented habitats negatively affect pollination, and female and male fitness, which will probably decrease the recruitment, survival and long-term viability of plant populations remaining in fragmented landscapes. We underline the main current gaps of knowledge for future research agendas and call not only for a decrease in the current rates of land-use changes across the world but also to embark on active restoration efforts to increase the area and connectivity of remaining natural habitats.

Reconstructing the introduction history of the invasive grass Taeniatherum caput-medusae subsp. asperum in the western United States: Low within-population genetic diversity does not preclude invasion

PREMISE

One of the main drivers of global change is biotic exchange, which leads to biological invasions. The genetic diversity and structure of invasive populations is influenced by multiple factors, most notably the details of a species' introduction, its pattern of range expansion, and its mating system. Taeniatherum caput-medusae subsp. asperum is a primarily self-pollinating, invasive, annual grass of the western United States (US).

METHODS

Using historical information (herbarium specimens and published reports) and genetic (allozyme) data, we reconstructed the introduction history and pattern of range expansion of T. caput-medusae subsp. asperum in its invasive range.

RESULTS

Herbarium collection data and published reports indicate that the grass was first collected near Roseburg, Oregon, in 1884 and then at Steptoe Butte, Washington, in 1901. Genetic analysis of 46 invasive populations of T. caput-medusae subsp. asperum detected seven homozygous multilocus genotypes (MLGs) across the western US. Several MLGs were found in localities associated with early collection sites. Only three of 1700 individuals we analyzed were heterozygous. Thus, high rates of self-pollination likely preserved the MLGs introduced into the western US and contributed to our ability to reconstruct the introduction history of this grass.

CONCLUSIONS

Our data are consistent with the pattern associated with multiple introductions and local or regional range expansion. Despite multiple introductions, invasive populations of T. caput-medusae subsp. asperum exhibit relatively low within-population genetic diversity (i.e., invasive populations possess low evolutionary potential). Apparently, low within-population genetic diversity does not preclude the invasion of this grass in the western US.

Environmental Stress and Resource Availability Affect the Maintenance of Genetic Variation in a Dominant Marsh Plant (Spartina alterniflora)

Changes in genetic variation, and particularly documented declines in genetic diversity, influence not only evolutionary potential but also current ecological function. Given this context, it is essential to understand what abiotic and biotic factors promote or disrupt the maintenance of genetic variation in natural populations. To address this knowledge gap in the context of salt marsh plants, we established a three-year field experiment, testing the independent and interactive effects of nutrient availability and physical stress on the maintenance of plant (Spartina alterniflora) genotypic diversity. We found that in environments with high physical stress (i.e., low marsh elevations), diversity declined over time. However, the addition of nutrients promoted the maintenance of Spartina genotypic diversity across the physical stress gradient. We also observed changes in genotypic composition and genetic divergence across environmental stress treatments, indicating variation among Spartina genotypes in their response to these factors. Our results suggest that tidal inundation acts a selective gradient within coastal marshes, altering genotypic diversity and composition across the landscape. Moreover, our work highlights that the effects of increasing inundation due to continued sea-level rise on the maintenance of diversity may be modulated by concomitant changes in nutrient inputs, with cascading effects on marsh structure and function.

Distribution of Population Sizes in Metapopulations of Threatened Organisms-Implications for Conservation of Orchids

Species are disappearing worldwide, and it is likely that the rate of their disappearance will increase. The most important factors responsible for this are assumed to be changes in climate and land use. To determine the probability of extinction of a given species, it must be viewed as a metapopulation composed of many populations. In plants, seeds are spread by wind or water (passive dispersers), unlike active dispersers, which can actively look for a suitable site of their species. Thus, while active dispersers can locate a suitable site, passive dispersers often fail to arrive at a suitable site. The following question arises: is it better for the survival of a metapopulation of passive dispersers to concentrate on conserving a few large populations, each of which will produce many propagules, or on many small populations, each of which will produce only few propagules? Here, we address the question of which of these strategies will maximize the likelihood of the survival of such a metapopulation, using orchids as a model. We concluded that small populations should be preferentially preserved. Small populations are more numerous and more likely to occur more widely in the region studied and therefore a larger proportion of the seeds they produce is more likely to land in suitable habitats than that produced by the fewer large populations. For conservation, there is a possibility to extend the results to other taxa. However, this must be carried out with caution and must consider the taxon in question.

Comparative analysis of floristic richness and diversity in six central forest reserves of north eastern Uganda

As the extinction risk of plants increases globally, there is need to prioritize areas with high floristic richness and diversity to inform the design of evidence-based conservation interventions. As such, this study aimed to comparatively analyse floristic diversity in six central forest reserves (CFR) of north eastern Uganda. This was guided by two objectives namely; (i) to determine the floristic richness and diversity in the CFRs and (ii) to evaluate the similarity and complementarity of floristic composition. Data was collected from nested quadrats (20 × 20 m for trees, 10 × 10 m for shrubs and 5 × 5 m for herbaceous climbers, forbs and grasses) placed at intervals of 100 m along a transect of 1000 - 1500 m. Species richness, diversity and evenness were determined for each CFR. Binary similarity coefficients were computed because only presence/absence data of plant species was recorded. A sum of 417 plant species in 76 families were recorded representing 8.7% of known vascular plants reported in Uganda. The CFRs have significantly variable Shannon-Wiener diversity indices ranging from 4.2 in Kano CFR to 4.47 in Bululu hill CFR (t = 85.291, df = 4, p = 0.00). The CFRs cluster into two groups namely Onyurut and Ogera hills and Akur, Kano, Bululu hills and Mount Moroto. The lowest similarity index was between Ogera hills and Moumt Moroto CFRs (0.37 or 37%) while the highest was between Akur and Kano CFRs (0.63 or 63%). The CFRs complement one another by supporting plant species not recorded elsewhere with three CFRs (Bululu hills, Mount Moroto and Onyurut) accounting for 81.53% of the plant taxa. The CFRs in NE Uganda have richness and floristic diversity with up to 8.7% of the known plants in Uganda present. The conservation status of these species is Vulnerable (4), Near Threatened (4), Least Concern (137), Data Deficient (1) and Not Evaluated (271). The two similarity clusters depict variation in altitudinal, proximity and climatic conditions. Five CFRs are required to conserve 95% of the species recorded. Therefore, the CFRs investigated play a complementary role in conserving the floristic diversity in north eastern Uganda.

Does Reproductive Success in Orchids Affect the Evolution of Their Number of Flowers?

Species are disappearing worldwide, and changes in climate and land use are commonly assumed to be the most important causes. Organisms are counteracting the negative effects of environmental factors on their survival by evolving various defence strategies, which positively affect their fitness. Here, the question addressed is: can evolution shape these defence strategies so that they positively affect the fitness of an organism? This question is complex and depends on the taxa and environmental factors. Therefore, here, only a special case of this question is studied in deceptive species of orchids: reproductive success (RS, ratio of the number of fruits to the number of flowers produced by a plant during the whole season), a commonly used measure of fitness is used to develop a model describing how RS affects the number of flowers, n, of a plant. This model predicts that: (i) the resulting relationship between RS and n is a positively skewed parabola, (ii) the distribution of the numbers of individuals with a specific number (n) of flowers, NI(n), also resembles a parabola and is also positively skewed, and that (iii) the peak of the distribution of NI is to the left of the peak of RS. A large set of data is presented that supports these predictions. If the data set is small, the concave positively skewed parabolic RS-n dependence is obscured by other factors.

Bryophytes as Indicators of Disturbance in One of the Last Remnants of the Mountain Forests of El Oro Province, Ecuador

Epiphytic bryophytes are an important component in terms of the diversity and functioning of montane forests known as biodiversity hotspots. Bryophytes are highly dependent on their external environments because they are sensitive to environmental changes related to disturbance, fragmentation, air pollution, and climate change. The richness and composition of bryophytes in remnants of primary and secondary forests were analyzed, where the richness and cover were recorded on trunk bases of 120 trees. Changes in species richness and diversity were analyzed using generalized linear models (GLMs), and changes in species composition, using multivariate analysis. A total of 57 bryophyte species (36 liverworts and 21 mosses) were recorded in trunk bases. For the first time, 19 new liverworts for the province of El Oro are reported. The richness and diversity of bryophyte species decrease in disturbed forests when compared to primary forests, with a marked decrease in species less adapted to conditions of high light (shade epiphytes). In the same line, species composition is different in each type of forest, where bryophytes with high humidity requirements were abundant in primary forests. This study confirms that forest disturbance is a key factor in determining not only the number of species but also the composition of bryophyte species. The maximum tree diameter and primary forest remnants are important factors in the conservation of sensitive bryophyte species at the base of trees in one of the last remnants of mountain forests in El Oro Province, Ecuador.

Local and landscape factors differently influence health and pollination services in two important pollinator groups

Agricultural management significantly affects insects, especially pollinators, which are crucial for crop pollination and biodiversity. In agricultural landscapes, various factors spanning different spatial scales are known to affect pollinator health, which, in turn, can influence pollination services. However, the importance of these factors in driving the health and performance of different pollinator groups remains unclear. Using a long-term biodiversity research platform, the German Biodiversity Exploratories, we investigated links between local and landscape-level land-use, health and pollination services in common pollinators, the bumblebee Bombus lapidarius and the syrphid fly Episyrphus balteatus, by measuring various traits as proxies for pollinator health and pollination services. Because of their different life histories, we expected the territorial bumblebees to be more vulnerable to land-use intensification at both spatial levels, compared with the migratory syrphid flies. Both land-use and environmental factors (climate) across spatial scales affected pollinator health, mostly via changes in body size: High land-use intensity reduced bumblebee body size, whereas higher ambient air temperature decreased syrphid fly body size. Increasing proportions of intensively managed areas at the landscape level decreased viral infections in both species. Additionally, landscape-level land-use and climate changed the bumblebees cuticular chemical profile, which is essential for communication in these social insects. Increasing land-use intensity at the local level and higher proportions of intensive land-use at the landscape level both had an indirect negative effect on pollination services in bumblebees via local flower cover and body size. Pollination services in both species were linked to body size. Thus, land-use factors affect pollinator health differently: bumblebees are more vulnerable to local and landscape-level land-use intensification, while syrphid flies are more resilient potentially due to their higher mobility. As pollinator health affects pollination services, our results indicate that land-use intensification poses a high risk to crops pollinated by species with small home ranges.

Local tree cover predicts mosquito species richness and disease vector presence in a tropical countryside landscape

CONTEXT

Land use change and deforestation drive both biodiversity loss and zoonotic disease transmission in tropical countrysides. For mosquito communities that can include disease vectors, forest loss has been linked to reduced biodiversity and increased vector presence. The spatial scales at which land use and tree cover shape mosquito communities present a knowledge gap relevant to both biodiversity and public health.

OBJECTIVES

We investigated the responses of mosquito species richness and Aedes albopictus disease vector presence to land use and to tree cover surrounding survey sites at different spatial scales. We also investigated species compositional turnover across land uses and along environmental gradients.

METHODS

We paired a field survey of mosquito communities in agricultural, residential, and forested lands in rural southern Costa Rica with remotely sensed tree cover data. We compared mosquito richness and vector presence responses to tree cover measured across scales from 30m to 1000m, and across land uses. We analyzed compositional turnover between land uses and along environmental gradients of tree cover, temperature, elevation, and geographic distance.

RESULTS

Tree cover was both positively correlated with mosquito species richness and negatively correlated with the presence of the common invasive dengue vector Ae. albopictus at small spatial scales of 90 - 250m. Land use predicted community composition and Ae. albopictus presence.

CONCLUSIONS

The results suggest that local tree cover preservation and expansion can support mosquito species richness and reduce disease vector presence. The identified spatial range at which tree cover shapes mosquito communities can inform the development of land management practices to protect both ecosystem and public health.

Evolution of competitive ability and the response to nutrient availability: a resurrection study with the calcareous grassland herb, Leontodon hispidus

Rapid environmental changes across Europe include warmer and increasingly variable temperatures, changes in soil nutrient availability, and pollinator decline. These abiotic and biotic changes can affect natural plant populations and force them to optimize resource use against competitors. To date, the evolution of competitive ability in the context of changes in nutrient availability remains understudied. In this study, we investigated whether the common calcareous grassland herb Leontodon hispidus recently evolved its competitive ability and response to nutrient availability. We compared ancestors sampled in 1995 and descendants sampled in 2018 and applied a competition treatment in combination with weekly nutrient treatments (no fertilizer, nitrogen, phosphorus, and both). We found evidence for evolution of increased competitive ability, with descendants producing more vegetative biomass than ancestors when grown under competition. Furthermore, supplementing nutrients (especially N) reduced differences in competitive ability between ancestors and descendants, suggesting that nutrients are a limiting factor in interspecific competition, which could be linked to the decreasing nitrogen emissions into the atmosphere since the 1990s. Our study demonstrates rapid contemporary evolution of competitive ability, but also the complexity of the underlying processes of contemporary evolution, and sheds light on the importance of understudied potential selection agents such as nutrient availability.

Double Trouble for Native Species Under Climate Change: Habitat Loss and Increased Environmental Overlap With Non-Native Species

Climate change and biological invasions are affecting natural ecosystems globally. The effects of these stressors on native species' biogeography have been studied separately, but their combined effects remain overlooked. Here, we develop a framework to assess how climate change influences both the range and niche overlap of native and non-native species using ecological niche models. We hypothesize that species with similar niches will experience both range reductions and increased niche overlap under future climates. We evaluate this using the ongoing invasion of smallmouth bass (Micropterus dolomieu) and northern pike (Esox lucius) on the native habitats of redband trout (Oncorhynchus mykiss) and bull trout (Salvelinus confluentus) in western North America. Future climate conditions will reduce habitat suitability for native and non-native species, but an increased niche overlap might exacerbate negative effects on native fishes. Our framework offers a tool to predict potential species distribution and interactions under climate change, informing adaptive management globally.

Estimates of microbial community stability using relative invader growth rates are robust across levels of invader species richness

A key feature of natural communities is that the species within them stably coexist. A common metric used to test community stability is the ability of each species to invade from rare. A potential issue with this measurement is that single species are invaded from rare, while in natural communities, multiple species would likely decline simultaneously following perturbations. This is especially common in microbes which can be rapidly disturbed by environmental stressors. If species coexistence is dependent on indirect interactions among community members, multiple species declining may result in community instability. As such, invading a single species into a community may overestimate the stability of a community when multiple species decline. Here, we compare estimates of community stability in a five species microbial community to experimental results in which multiple species are simultaneously invaded. Our results showed that single species invasions were qualitatively predictive of whole community stability when multiple species are invaded simultaneously. However, quantitative values of relative invader growth rate were less comparable, being non-significantly different in most comparisons in three out of five species. This was emphasized by the lack of correlation between exact values of growth rates under single or multi-species invasion. This work provides experimental support for the robustness of using invasion growth rate of single species to infer qualitative estimates of community stability.

A quantitative approach to ranking management actions for an endangered pool-breeding amphibian

Management of vulnerable amphibian populations requires a better understanding of the habitat factors that will make the greatest difference in their preservation. We set out to develop a predictive model of amphibian abundance based on habitat characteristics that may influence their survival and persistence. Our study system was the Sonoma County California tiger salamander (Ambystoma californiense; SCTS), an amphibian threatened by habitat loss and fragmentation. In 2019, 298 ponds (almost every breeding pond in this federally endangered Distinct Population Segment) were surveyed to determine SCTS larval densities, a proxy for population well-being. We used model selection to identify which factors of pool morphology, the surrounding pool neighborhood, and terrestrial upland habitat best predict variation in larval densities. Our best model showed a significant positive relationship between larval SCTS densities and three variables: pool depth, number of breeding pools within 500 m of a focal pool, and amount of suitable and accessible upland habitat within 1500 m of a pool. To further refine this model, we then examined interactions and non-linearities using a generalized additive model. Based on this refined model, we simulated a variety of management scenarios to identify which management practices would most increase larval densities across the endangered Distinct Population Segment and where on the landscape employing each mitigation action would yield the greatest return. This provides the basis for a county-wide Habitat Conservation Plan for SCTS, and highlights habitat characteristics likely critical to the conservation of other pond-breeding amphibians.

Herbivory can increase plant fitness via reduced interspecific competition-evidence from models and mesocosms

Herbivores are generally considered to reduce plant fitness. However, as in natural communities they often feed on several competing plant species, herbivores can also increase plant fitness by reducing interspecific competition among plants. In this study, we developed a testable model to predict plant fitness in the presence of an interspecific competitor and a herbivore that feeds on both plant species. Our model allows prediction of the herbivore and competitor densities at which the focal species will benefit from herbivory. This can be estimated by quantifying the effects of the herbivore on the fitness of the focal plant and on its competitor, and by estimating the levels of intra- and interspecific competition in a pairwise fashion, respectively. We subsequently validated the model in indoor microcosms using three interacting species: an aquatic macrophyte (the giant duckweed Spirodela polyrhiza), its native competitors (green algae) and its native herbivore (the pond snail Lymnaea stagnalis). Additional outdoor mesocosm experiments supported our model under natural conditions. Together, this study provides a conceptual framework to understand how herbivores shape plant fitness in a community context.

Proposed Relationships Between Climate, Biological Soil Crusts, Human Health, and in Arid Ecosystems

Biological soil crusts (or biocrust) are diminutive soil communities with ecological functions disproportionate to their size. These communities are composed of lichens, bryophytes, cyanobacteria, fungi, liverworts, and other microorganisms. Creating stabilizing matrices, these microorganisms interact with soil surface minerals thereby enhancing soil quality by redistributing nutrients and reducing erosion by containment of soil particles. Climatic stressors and anthropogenic disturbances reduce the cover, abundance, and functions of these communities leading to an increase of aeolian dust, invasive plant establishment, reduction of water retention in the environment, and overall poor soil condition. Drylands are the most degraded terrestrial ecosystems on the globe and support a disproportionately large human population. Restoration of biocrust communities in semi-arid and arid ecosystems benefits ecosystem health while decreasing dust emissions. Dust abatement can improve human health directly but also indirectly by reducing pathogenic microbe load circulating in the ambient air. We hypothesize that biocrusts not only reduce pathogen load in the air column but also inhibit the proliferation of certain pathogenic microbes in the soil. We provide a review of mechanisms by which healthy biocrusts in dryland systems may reduce soil-borne pathogens that impact human health. Ecologically sustainable mitigation strategies of biocrust restoration will not only improve soil conditions but could also reduce human exposure to soil-borne pathogens.