Ecology Letters最新文献

Quantifying how co-acting global change factors (GCFs) influence plant invasion is crucial for predicting future invasion dynamics. We did a meta-analysis to assess pairwise effects of five GCFs (elevated CO₂, drought, eutrophication, increased rainfall and warming) on native and alien plants. We found that alien plants, compared to native plants, suffered less or benefited more for four of the eight pairwise GCF combinations, and that all GCFs acted additively. Subgroup analysis showed that the relative benefits of alien over native plants were particularly apparent when they grew in competition with one another, and that the results were largely the same when the aliens were restricted to naturalised or invasive species. Our meta-analysis provides evidence that additive effects of multiple global change factors on plant invasions are common, and thus that with the ongoing global environmental changes, the risk of plant invasion continues to increase.

Accurately representing the relationships between nitrogen supply and photosynthesis is crucial for reliably predicting carbon–nitrogen cycle coupling in Earth System Models (ESMs). Most ESMs assume positive correlations amongst soil nitrogen supply, leaf nitrogen content, and photosynthetic capacity. However, leaf photosynthetic nitrogen demand may influence the leaf nitrogen response to soil nitrogen supply; thus, responses to nitrogen supply are expected to be the largest in environments where demand is the greatest. Using a nutrient addition experiment replicated across 26 sites spanning four continents, we demonstrated that climate variables were stronger predictors of leaf nitrogen content than soil nutrient supply. Leaf nitrogen increased more strongly with soil nitrogen supply in regions with the highest theoretical leaf nitrogen demand, increasing more in colder and drier environments than warmer and wetter environments. Thus, leaf nitrogen responses to nitrogen supply are primarily influenced by climatic gradients in photosynthetic nitrogen demand, an insight that could improve ESM predictions.

Microbial traits are critical for carbon sequestration and degradation in terrestrial ecosystems. Yet, our understanding of the relationship between carbon metabolic strategies and genomic traits like genome size remains limited. To address this knowledge gap, we conducted a global-scale meta-analysis of 2650 genomes, integrated whole-genome sequencing data, and performed a continental-scale metagenomic field study. We found that genome size was tightly associated with an increase in the ratio between genes encoding for polysaccharide decomposition and biomass synthesis that we defined as the carbon acquisition-to-biomass yield ratio (A/Y). We also show that horizontal gene transfer played a major evolutionary role in the expanded bacterial capacities in carbon acquisition. Our continental-scale field study further revealed a significantly negative relationship between the A/Y ratio and soil organic carbon stocks. Our work demonstrates a global relationship between genome size and the encoded carbon metabolic strategies of soil bacteria across terrestrial microbiomes.

The geographic mosaic of coevolution predicts reciprocal selection, the first step in coevolution, to vary with changing biotic and abiotic environmental conditions. Studying how temperature affects reciprocal selection is essential to connect effects of global warming on the microevolutionary patterns of coevolution to the ecological processes underlying them. In this study, we investigated whether temperature influenced reciprocal selection between a plant (Brassica rapa) and its pollinating butterfly herbivore (Pieris rapae). In two temperature environments (ambient and hot), we measured the phenotypes of plants and butterflies, their interactions and fitness, which we used to calculate reciprocal selection. We found a variety of traits involved in reciprocal selection in the ambient environment, but none in the hot environment. We provide experimental evidence that elevated temperature weakens reciprocal selection, which will help better predict the consequences of global warming for coevolution.

Leaf dry matter content (LDMC) is an important determinant of plant flammability. Investigating global patterns of LDMC could provide insights into worldwide plant flammability patterns, informing wildfire management. We characterised global patterns of LDMC across 4074 species from 216 families, revealing that phylogenetic and environmental constraints influence LDMC. LDMC varied across growth forms and taxonomic groups, displaying phylogenetic niche conservatism. Temperature, precipitation, aridity index, soil total nitrogen content and wildfire activity affected LDMC, and the effect of wildfire activity was stronger than other environmental factors across species with postfire regeneration abilities. Such species had higher LDMC, and their LDMC was less phylogenetically conserved and more strongly associated with fire activity. Our results suggest that, although LDMC shows phylogenetic niche conservatism, LDMC is determined by environmental factors, especially wildfire activity. Wildfire has likely acted as a selective pressure towards high LDMC across species that persist through fire using postfire regeneration.

Climate change is intensifying extreme weather events, with severe implications for ecosystem dynamics. A key behavioural mechanism whereby animals may cope with such events is by altering their social structure, which in turn could influence epidemic risk. However, how and to what extent natural disasters affect disease risk via changes in sociality remains unexplored in animal populations. By simulating disease spread in free-living rhesus macaques (Macaca mulatta) before and after a hurricane, we demonstrate doubled pathogen transmission rates up to 5 years following the disaster, equivalent to an increase in pathogen infectivity from 10% to 20%. Moreover, the hurricane redistributed the risk of infection across the population by exacerbating sex-related differences. Overall, we demonstrate that natural disasters can amplify and redistribute epidemic risk in animals via changes in sociality. These observations provide unexpected further mechanisms by which extreme weather events can threaten wildlife health, population viability and spillover to humans.