Ecology Letters最新文献

Exploitative interactions, such as predator–prey and host–parasite interactions, are ubiquitous in microbial communities. These interactions shape community density and composition, imposing strong selection on members to evolve countermeasures reducing the negative impacts of exploitation. Exploitative coevolution is often studied between species pairs in isolation, which may overestimate the strength and relevance of pairwise coevolution. Here we studied how community context influences coevolution between Pseudomonas fluorescens (exploited) and Variovorax sp. (exploiter). We evolved these species in pairwise coculture and embedded within a five-species community to investigate evolved changes in pairwise interactions. We found evidence for asymmetrical coevolution: Variovorax evolved more rapidly than Pseudomonas, leading to increased exploitation through time, while Pseudomonas evolved increased tolerance to Variovorax with a time lag. The pairwise coevolutionary dynamics were not affected by the presence of other community members. Understanding how coevolutionary patterns change with increasing community complexity can have important implications for community persistence and function.

Carryover effects broadly influence adult performance and population persistence. Although variation in developmental environments can have contrasting effects on survival and reproduction, current predictive models of vulnerability to environmental change typically ignore simultaneous changes in both fitness components. We tested how developmental temperatures shape survival and multiple aspects of reproduction in a plant-living insect (Enchenopa binotata treehoppers) and used population dynamic models to examine the cumulative impact of these complex effects on population growth. We show that elevated developmental temperatures increase adult fertility, offsetting reduced juvenile survival and potentially forestalling population declines following global warming. Moreover, pairing mates from different developmental temperatures exacerbated morphological mismatches between sexes, reducing mating success and sperm transfer. Our findings thereby provide novel evidence that thermal carryover effects can generate assortative mating and selection on adult reproductive morphology, in addition to shaping the relative importance of survival and reproduction for persistence in warming climates.

How alien plant species integrate into local native communities remains a widely debated but largely unresolved question. For 12,460 plant communities from six different habitats, we show that naturalized non-invasive species integrate near the center of the multidimensional functional trait space of each community, whereas invasive species tend to occupy the edges. This pattern is driven mainly by specific leaf area, plant height and seed mass, followed by genome size. These results suggest that functional similarity to resident native species supports successful naturalization of alien species through preadaptation to environmental conditions. In contrast, the functional dissimilarity of invasive species enables them to exploit new niches, potentially avoiding direct competition with co-occurring native species while still passing through environmental filters. The magnitude of differences between native, naturalized and invasive species is habitat-specific, reflecting both the local ecological conditions and the traits of the most widespread species in a given habitat.

Although biodiversity is widely recognised for its role in maintaining ecosystem functioning under environmental change, its importance has received relatively little attention in the context of emerging environmental stressors such as nanoparticles. By assembling phytoplankton communities across a gradient of species richness and exposing them to varying concentrations of copper oxide nanoparticles, we experimentally explored how biodiversity modulates ecosystem functioning under nanoparticle exposure. We found that the positive effect of biodiversity on phytoplankton biomass production was amplified at higher nanoparticle concentrations, allowing diverse communities to maintain biomass despite strong inhibitory effects of nanoparticles on monocultures. This enhanced biodiversity effect was primarily driven by increased complementarity, specifically through more frequent facilitative interactions among species under nanoparticle stress. Our findings advance the understanding of how biodiversity preserves ecosystem functioning and underscore its role in mitigating the impacts of emerging anthropogenic stressors.

The distribution of biodiversity depends on processes operating across scales, yet multiscale paradigms have struggled to permeate host-microbiome research. Instead, host-microbiome research has focused on host selection and has struggled to explain the high variation in microbial composition across individuals. By integrating multi-scale ecological theory with experimental manipulation of bacteria colonizing monarch butterfly caterpillars, we test the hypothesis that immigration from the regional species pool alters the importance of niche selection and drift in causing variation in gut bacterial communities across individuals and through ontogeny. Higher immigration increased the dominance of certain bacteria, causing greater convergence in bacterial composition across the caterpillar life stage. Conversely, limited immigration made colonization more stochastic, resulting in more unpredictable variability in bacterial composition across individuals. Our study reveals that immigration mediates the balance between host selection and drift, demonstrating that processes operating at scales beyond the individual are underappreciated but critical for structuring host-microbiome symbioses.

Intraspecific variation is a fundamental component of biodiversity, shaping species interactions and coexistence dynamics. While numerous mechanisms have been proposed to shape the degree of phenotypic variation within species, many remain largely untested or poorly explored at broad spatial and taxonomic scales. Using data from nearly 200,000 bird captures from 99 species across North America, we investigated hypothesized drivers of within-population phenotypic variation, using body mass and wing length as traits of interest. The magnitude of observed phenotypic variation was modulated by a combination of geographic, environmental, and life history factors. This was true whether considering differences in within-population phenotypic variation within or among species. The impact of these non-mutually exclusive mechanisms has resulted in substantial variation in the observed magnitude of within-population phenotypic variation. These results provide empirical evidence for a set of long-standing hypotheses regarding the processes that regulate observed patterns of this understudied, but important, component of biodiversity.