Ecology Letters最新文献

Invasion fronts are the advancing edges of non-native species' ranges and represent dynamic, non-equilibrium boundaries where colonization, biotic interactions and rapid evolutionary processes interact. Although biological invasions are increasingly well studied, the ecological and evolutionary mechanisms operating at invasion fronts remain conceptually fragmented despite their disproportionate influence on spread dynamics, exerted impact and management. Here, we synthesize how invasion-front geometries arise from interactions among propagule pressure, landscape permeability, long-distance dispersal and environmental heterogeneity, producing continuous (including satellite colonies), patchy/fragmented or coalescing fronts that shift with invasion stage and spatiotemporal scales. We integrate ecological and evolutionary evidence from macro-organisms to show how gradients from core to front can result in declining population density, increased trait divergence, spatial sorting, serial founder effects, expansion load, and behavioural and physiological differentiation. We further draw parallels with climate-driven range expansions, while emphasizing the stronger disequilibrium and novel biotic contexts characteristic of non-native invasion fronts. Finally, we map these dynamics onto impact trajectories, demonstrating how trait-mediated interactions, resource reallocation and system-level reconfiguration can emerge sequentially along the invasion gradient. By unifying ecological and evolutionary processes across appropriate spatial and temporal scales, we establish invasion fronts as powerful natural laboratories and critical leverage points for predicting, monitoring and managing biological invasions.

Coinfections by multiple parasite species are widespread and often modify disease outcomes. To what degree other forms of ecological complexity, such as environmental change, influence the impacts of coinfecting parasites on disease remains unclear. We exposed nematodes (Caenorhabditis elegans) to naturally coinfecting parasites (Leucobacter celer and Leucobacter musarum) at temperatures across the host's thermal range. While we found that host mortality varied widely with temperature during single infections, coinfections buffered hosts against temperature-mediated variation via ongoing parasite competition. We extended our experiments with mathematical models indicating that changing virulence, rather than transmission, most plausibly underpins temperature-dependent host mortality. At moderate, but not extreme temperatures, we found coinfection continued to dampen mortality outcomes due to another source of host variation, genotypic susceptibility. Coinfection may provide a stabilizing effect on disease in a warming world—but this effect can falter when hosts are faced with multiple stressors.

Fire is a fundamental process that structures community assembly and biodiversity patterns; however, altered disturbance regimes associated with anthropogenic change present a major threat to fire-adapted systems. Reintroducing fire to increase pyrodiversity (spatiotemporal diversity in fire) has been identified as an important step in restoring fire-adapted western temperate forests. Here, we utilize phylogenetic and taxonomic metrics to assess how pyrodiversity influences plant community assembly dynamics and diversity patterns in the central Sierra Nevada, California, USA. Compared to fire exclusion, regional taxonomic and phylogenetic diversity generally increased after fire. Further, with increased pyrodiversity, community assembly mechanisms diversified and occurrences of diverse plant lineages and local phylogenetic endemism increased, illustrating how evolutionary history influences responses of plants to pyrodiversity. These results demonstrate the importance of restoring mixed-severity fire to these systems and how phylogenetic tools can provide a valuable way to understand and monitor restoration impacts.

Understanding the overlooked ecology of our homes can provide ecologists with unprecedented data and fresh ideas while also informing broader societal concerns. By studying the biodiversity we interact with most often, ecologists can foster appreciation for the significance of ecological and evolutionary insights in our everyday lives.

Body size is a master variable in ecology that can predict ecosystem-level processes and reflect environmental conditions across diverse ecosystems. In freshwater ecosystems, the relationship between body size and biomass provides a powerful tool for characterizing community structure and trophic transfer efficiency. While these relationships are well established at the whole-community level, responses within plankton functional groups with distinct ecological characteristics have yet to be explored. In this study, we analysed plankton biomass-size relationships across > 550 Canadian lakes. For phytoplankton, we found that mixotrophs exhibited positive biomass-size slopes, while autotrophs exhibited negative slopes. For zooplankton, herbivores exhibited relatively flat slopes, while non-herbivores exhibited negative slopes. Biomass-size relationships also differed among lake trophic states, but only for phytoplankton functional groups. This work should improve predictions and assessments of freshwater ecosystem functioning and food web pathways, based on our observation of directional shifts in biomass-size relationships across functional groups and trophic states.

Global change reshapes arthropod communities, yet long-term effects on their functional diversity remain unclear. Using a long-term dataset comprising > 1.3 million individuals of 728 carabid and spider species, we quantified temporal trends in functional diversity across forests, grasslands and croplands. Trajectories diverged strongly among land uses: functional richness increased in forests and grasslands but declined sharply in croplands. In forests, communities became more specialised and less redundant, suggesting increasing niche differentiation, but experienced greater functional richness loss under simulated species extinctions. Cropland assemblages became functionally homogenised. Losses of key effect traits among spiders suggest potential erosion of ecosystem functions in croplands. Moreover, genera dominated by species with unique trait combinations were typically larger-bodied and less dispersive, and their loss would remove irreplaceable functional strategies from communities. Overall, our study reveals diverging long-term trajectories of arthropod functional diversity across land uses, indicating potential negative consequences for ecosystem functioning in arable landscapes.