Ecology Letters最新文献

Proximity to natural habitat is known to enhance pollination services in large-scale agriculture, but it remains unclear whether this holds in tropical smallholder farms. These systems are embedded in ecologically complex landscapes, central to global food security, and depend heavily on biodiversity-derived ecosystem services. We conducted a systematic review and meta-analysis of 35 studies assessing the relationship between distance to natural habitat and pollinator abundance, species richness, and crop fruit set in tropical smallholder farms. We found no consistent patterns in pollinator abundance and crop fruit set with increasing distance, with relationships highly variable across studies. Similarly variable, yet slightly negative, was the relationship between distance and pollinator species richness. Our findings suggest limited support for the ‘proximity to natural habitat’ hypothesis in tropical smallholder farms, indicating that the inherent complexity of these landscapes may buffer negative effects of distance on pollination. This underscores the importance of maintaining and restoring landscape complexity to sustain biodiversity and ecosystem services such as crop pollination. We also highlight the need for greater methodological consistency and publicly available raw data in future studies to strengthen the evidence base and support management strategies for safeguarding pollination services in tropical smallholder farms.

Prevailing views hold that species' physiological plasticity may confer resilience to warming, but its importance varies across climatic gradients (e.g., latitude). Yet, along such gradients local species populations may experience fine-scale spatially heterogenous variation in extreme temperatures and other ecological stressors. We show that at four Cool (mean diel maximum 29.83°C) and four Warm (mean diel maximum 31.51°C) sites, interspersed as a spatial mosaic throughout a 26,200 km² area, local herbivore populations responded differently to stress from experimental warming (ambient, warmed) and predation (presence, absence). Cool and Warm site herbivore populations utilised different combinations of behavioural and physiological plasticity to cope with the dual stressors that were contingent on local temperature extremes. These unique plastic responses had divergent cascading effects on the plant community. Our results suggest that increased attention to local population variation can enhance the ability to predict the fate of natural communities under environmental change.

Modular organisms such as fungi are assumed to exhibit extreme morphological plasticity, yet this assumption has rarely been tested experimentally. Their morphology emerges from local, independent responses of constituent modules, suggesting strong plastic responses to environmental conditions. While such levels of plasticity decouple morphology from ecological function, they make these organisms an ideal system for studying the evolution of plasticity. Here we quantified the plasticity of modular fungi to grazers with known strong effects on their fitness and tested two competing hypotheses: (1) fungal morphology converges on a common ‘grazing-resistant’ phenotype across species (i.e., extreme plasticity) or (2) grazer-induced plasticity remains limited and species-specific. We found support for the latter, suggesting a more nuanced plasticity for fungi than would be expected based on their modularity. Our study calls for refining assumptions about plasticity in modular organisms and informs the use of morphological traits as predictors of ecological function.

Ectotherms tend to mature at smaller sizes as average temperatures rise, a pattern known as the Temperature-Size Rule (TSR), which also predicts earlier age at maturity. However, in natural environments, warming is often accompanied by increased thermal variability and limited nutritional resources. Using a bioenergetic model combined with factorial growth experiments on Daphnia, we investigated how temperature, food concentration, and food quality (Polyunsaturated fatty acid and sterol content) jointly shape size and age at maturity. We find that poor food quality narrows the upper thermal limit for TSR expression, while low food quantity restricts both upper and lower thermal bounds. Increased thermal variability shifts this range towards cooler temperatures. These findings suggest that the TSR may not hold under ecologically realistic conditions, especially when organisms are close to their thermal optimum where small concomitant increases of resource limitation and temperature variability with warming may lead to smaller yet older individuals at maturity.