Ecology Letters最新文献

Viral transfer from managed pollinators potentially threatens wild pollinators and may be exacerbated by land-use changes. Our causal models and plant-pollinator network data from 48 European urban and agricultural landscapes revealed the ecological mechanisms underpinning viral transmission. Host identity, network architecture and land-use modulated viral dynamics (black queen cell virus, BQCV; deformed wing virus, DWV-A and DWV-B). Viral prevalence in wild pollinators was driven by viral density in the reservoir host: honey bees, and secondarily by trophic niche overlap with these managed pollinators. Modular networks limited BQCV prevalence, which was driven by reduced honey bee niche overlap, suggesting minimal onward transmission among wild pollinators. Landscapes supporting greater wild pollinator abundance diluted DWV-B transmission; in urban landscapes managed honey bees and wild pollinators experienced higher and lower BQCV prevalence, respectively. Disease in managed bee colonies and land-use changes that concentrate pollinator foraging interactions present potential viral risks to wild pollinator health.

Specific recognition of microbial virulence factors (effectors) by host defence proteins can generate negative frequency-dependent selection (NFDS), enabling the maintenance of strain diversity. Our characterisation of 76 Midwestern US Pseudomonas syringae strains and 1104 global strains confirmed high strain diversity, but also revealed that strains are structured into similarity modules, consistent with core genome phylogeny but unexplained by host, location or genetic linkage. We developed a stochastic computational model that embraces the large variability now known to characterise effector repertoires. We show that NFDS can not only generate modular strain structure but is required to maintain modularity under genetic exchange, for which there is evidence in the data. These modules form through the emergence of groups of pathogens virulent to dominant hosts at a given time. Thus, eco-evolutionary dynamics contribute to strain coexistence through flux in the modules that represent niches within the host population.

Increasing drought frequency and intensity affect biophysical functions of natural ecosystems. In tropical semi-arid savannas, while immediate drought effects are well-studied, the drought legacy effects on vegetation composition and associated ecosystem functions remain unclear. We used data of vegetation composition, net ecosystem CO₂ exchange, surface albedo and evapotranspiration (ET) in 2017-2022 from a savanna ecosystem, Southwest China, to investigate the legacy effect of an extreme drought event that occurred in 2019. Vegetation declined continuously for 3 post-drought years. While tree numbers declined by 12%, shrub numbers dropped by 50% compared with pre-drought levels, shifting vegetation dominance toward trees. This structural change caused sustained reductions in albedo and ET, which remained below pre-drought levels, despite gross primary production recovering in the years immediately post-drought. Vegetation shifts disproportionately impact ecosystem functions, with energy and water fluxes exhibiting greater vulnerability and potentially enhancing regional warming as droughts increase in Asian savannas.

A significant area of current research is the impact of warming on trophic networks. However, few interactions per network are typically studied, which limits generalisation and precludes evaluation of impact on consumer diet breadth and redundancy of top-down control. Here we show that experimental warming strongly decreased the success of parasitoid development across 28 Drosophila-parasitoid interactions from a tropical rainforest network. Parasitoids responded consistently despite deep evolutionary divergence. Moreover, warming strongly narrowed the diversity of hosts that the parasitoids could use. Host developmental success was much less affected. In contrast, experimental cooling had only a mild effect on parasitoids and hosts. Our findings suggest that the top-down control exerted by parasitoids is likely to weaken due to warming. The range of hosts that parasitoids can use will become more limited, potentially threatening the sustainability of parasitoid populations and changing the balance between trophic levels.

Root exudates act as key energy and signalling carriers linking roots with rhizosphere microbes, yet how their quantity and quality mediate root-microbe coordination remains unclear. Here, we measured fine root exudation rates and chemical composition, functional traits, and soil microbial communities across 13 coexisting subtropical tree species. Root exudation release rates and composition tightly aligned with the conservative-acquisitive root economics spectrum, bridging strategic synergy between roots and their microbial partners. Acquisitive roots with higher nitrogen concentrations released exudates at higher rates and greater chemodiversity, supporting more diverse microbial communities enriched in fast-growing copiotrophs and saprotrophic fungi, but with reduced symbiotic fungal abundance, whereas conservative roots with higher tissue density showed the opposite pattern. These results highlight root exudate, especially its chemical composition, as a key trait shaping the root-microbe functional continuum, providing novel insights into mechanisms of belowground functional integrations which affect species coexistence and ecosystem functioning under environmental change.

Trait-based approaches are key to understanding eco-evolutionary processes but rarely account for animal behaviour despite its central role in ecosystem dynamics. We propose integrating behaviour into trait-based ecology through movement traits—standardised and comparable measures of animal movement derived from biologging data, such as daily displacements or range sizes. Accounting for animal behaviour will advance trait-based research on species interactions, community structure and ecosystem functioning. Importantly, movement traits allow for quantification of behavioural reaction norms, offering insights into species’ acclimation and adaptive capacity to environmental change. We outline a vision for a ‘living’ global movement trait database that enhances trait data curation by (1) continuously growing alongside shared biologging data, (2) calculating traits directly from individual-level data using standardised, consistent methodology and (3) providing information on multi-level (species, individual, within-individual) trait variation. We present a proof-of-concept ‘MoveTraits’ database with 52 mammal and 97 bird species, demonstrating calculation workflows for 5 traits across multiple timescales. Movement traits have significant potential to improve trait-based global change predictions and contribute to global biodiversity assessments as Essential Biodiversity Variables. By making animal movement data more accessible and interpretable, this database could bridge the gap between movement ecology and biodiversity policy, facilitating evidence-based conservation.

Increased frequency and severity of droughts threatens forest health worldwide. Tree species-specific adaptations—for example, dry-season deciduousness in tropical seasonal forests—and individual traits—for example, size, crown position—shape drought resistance, but such resistance may be variable across species, microenvironments and drought events. Here, we assess growth responses of 1820 trees across 30 species to three climatically distinct droughts in a seasonally dry tropical forest in Western Thailand. Species and individuals exhibited a wide range of growth responses within each drought, and differences in response intensity and affect among the drought events. Deciduous and evergreen species were more sensitive to wet- and dry-season drought respectively. While individuals with more exposed crowns tended to grow less in all droughts, stem diameter and topographic wetness had variable effects. Heterogeneous drought responses of species and individuals indicate potential biological insurance effects in diverse forests in the face of increased drought.

Communities can buffer environmental change through diverse responses of their species, often leading to greater stability than expected from individual species. Metrics such as response dissimilarity (variation in magnitude) and divergence (variation in direction) capture this response diversity in fluctuating environments. We test whether response diversity also stabilises community properties under pulse disturbance. Combining model simulations of multi-species communities with empirical data from a meta-analysis, we find that community stability was consistently determined by the species mean response, regardless of interaction strength. Contrastingly, response dissimilarity and divergence were only related to stability in the absence of interspecific interactions. While response diversity increases stability under fluctuating conditions, pulse disturbances cause negative responses in most species and stability is highest when species uniformly exhibit strong resistance or fast recovery. These results highlight that the role of response diversity in promoting community stability depends on disturbance regimes and is shaped by species interactions.

Maintaining genetic diversity within and among populations is critical for conservation and a prominent goal of the Kunming-Montreal Global Biodiversity Framework. However, direct estimates of genetic diversity are unavailable for most species, and time and resources are insufficient to fill these substantial data gaps and meet conservation target timelines. We evaluated a proxy-based prediction of genetic diversity loss, the Genetic Diversity Area Relationship (GDAR), which describes relationships between genetic diversity and the geographic area occupied by a species. We estimated differences in three metrics of genetic diversity relative to sample area using 55 previously published datasets from 51 species. GDARs were highly variable across species and strongly dependent on population structure, with no clear differences across vertebrate classes. Traits correlated with population structure and study area explained 35%–45% of the variation in GDARs. Across genetic diversity metrics, prediction accuracy was highest for GDARs estimated from allele count compared to allelic richness and gene diversity. Our findings suggest there are opportunities for refining taxon-specific GDARs to predict genetic diversity loss following area loss in the absence of genetic data.