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.

Feeding the largest share of the global population, cereal production must enhance sustainability while ensuring food security under global change. Unfortunately, the number of sustainable practices needed to support production, ecosystem services and land conservation remains virtually unknown. We compiled a database of 1570 observations from 349 sites in 57 countries to assess how the number of sustainable practices influences multiple ecosystem services. Our findings reveal that a high number of sustainable practices is crucial for enhancing agroecosystem services such as soil carbon storage, fertility and microbial habitat while supporting yield. Sustainable practices such as crop rotation, limited tillage and incorporation of crop residues were especially important. North America, Eastern Europe and China were particularly dependent on the use of multiple sustainable practices to maintain ecosystem services. Findings underscore the need for integrative strategies employing multiple sustainable practices for mitigating global change, ensuring food security and sustaining ecosystems.

Statistical autocorrelation between sampling units violates independence assumptions in many analyses. Here, we used simulations and empirical analyses to demonstrate how shared evolutionary history between species and species overlap among communities leads to an insidious form of autocorrelation, termed compositional autocorrelation. We simulated compositionally autocorrelated ecosystem functions across communities and assessed the type I error, statistical power and accuracy of slope estimates from naïve linear regression models and mixed models accounting for compositional autocorrelation. Mixed models maintained lower type I error, similar or higher statistical power, and more accurate slope estimates compared to linear regression. Re-analysing an empirical dataset, we found linear regression underestimated uncertainty in species richness effects for eight of 10 ecosystem functions. As species overlap and shared evolutionary history are common features in community data, our results highlight the need to explicitly consider compositional autocorrelation in statistical analyses to ensure correct inferences.

Biodiversity can buffer ecosystem functioning against disturbances by allowing species to compensate for the functions lost through the extirpation of other species, a key process known as ecological insurance. Functional ecology has extended this idea by emphasising trait redundancy amongst species that help buffer core ecosystem functions. However, some functions might be supported only by species with distinct combinations of trait values, which are less likely to be redundant within local communities. Here, we present a new and widely applicable framework to quantify the spatial insurance of locally functionally distinct species amongst communities. Our framework characterises how communities can disproportionately insure (functional sources) or depend on (functional sinks) neighbour communities, a dual relationship that is not captured by traditional metrics of functional beta diversity. We illustrate the application of our framework at broad spatial scales for plants and birds, highlighting biogeographic patterns of functional sources and sinks. This trait-based spatial perspective reveals functional vulnerability, as illustrated by bird communities where functional sources were disproportionately impacted by human activities. It also provides a new approach to identify regions that differ in potential resilience to environmental change and to inform conservation strategies grounded in spatial trait distributions, supporting the preservation of functional distinctiveness beyond a focus on local biodiversity metrics.

Anticipating ecosystem responses to global change requires identifying the isolated and combined effects of environmental disturbance across both space and time. Examining the coordinated responses of ecosystems has recently emerged as a powerful approach to advance this understanding. We conducted two complementary experiments to identify whether, and if so how, warming temperatures, nutrient enrichment, predator overexploitation (i.e., reduced apex predator abundance) and their combination drive coordinated responses of freshwater ecosystems by evaluating the dynamics of synchrony between control and disturbed mesocosms using high-frequency dissolved oxygen saturation measurements, an integrative parameter of the metabolic balance of ecosystems. Nutrient enrichment desynchronized the oxygen dynamics and their component cycles between treatments, likely arising from elevated primary production. Warming and overexploitation tended to desynchronize oxygen cycles from the control, particularly at short time scales. Nutrient enrichment combined with warming dampened desynchronization between control (ambient) and treatment mesocosms, whereas desynchronization was enhanced when simultaneously subject to predator overexploitation. As one of the first experimental demonstrations of global change impacts on ecosystem synchrony, this study highlights the need—and opens new avenues—to detect alterations in ecosystem functioning across previously unexplored spatial and temporal scales.