Ecology Letters最新文献

Pollinators receive considerable interest due to their fundamental role in ecosystem functioning and human well-being. Unlike farmlands, studies of urban pollinator-promoting interventions are scarce and have not been synthesised, hampering policy implementation. To fill this gap, we compared pollinator-promoting interventions (treatment) with conventionally managed (control) sites regarding vegetation, floral resources, and pollinators. Our synthesis investigated 1051 sampling sites with different interventions (abandonment, extensive mowing, flower sowing, and combined practices) and habitats (parks, grasslands, road verges, private and public gardens) from 28 European datasets at pooled- and study-levels. Urban pollinator-promoting interventions generally benefited plants and pollinators with taxon, intervention, habitat, and spatio-temporal specific differences. Pooled analyses showed mostly positive and never negative treatment effects, while study-level details described primarily positive and neutral but rarely negative effects. Bumblebees and butterflies benefited most from the interventions. Some effects were stronger for interventions involving flower sowing, interventions occurring in road verges, and interventions located in Northwestern Europe. Although regulations, guidelines, and monitoring are improving, knowledge gaps remain for some pollinator taxa (e.g., beetles), regions (e.g., Mediterranean), and novel interventions (e.g., for ground-nesting insects). Further collaborative studies from around the world could help cities bring people, plants, and pollinators together by creating resilient, multi-functional urban spaces.

A core hypothesis in invasion and community ecology is that species interaction patterns should differ between native and non-native species due to non-native species lacking a long evolutionary history in their resident communities. Numerous studies testing this hypothesis yield conflicting results, often focusing on mean interaction rates and overlooking the substantial within-population variability in species interactions. We explored plant-herbivore interactions in populations of native and established non-native plant species by quantifying differences in mean herbivory and added a novel approach by comparing within-population variability in herbivory. We include as covariates latitude, plant richness, plant growth form and cover. Using leaf herbivory data from the Herbivory Variability Network for 788 plant populations spanning 504 species globally distributed, we found no overall differences in mean herbivory or variability between native and non-native plants. These results suggest native and established non-native plants interact similarly with herbivores, indicating non-native status is not a strong predictor of ecological roles.

Following alarming studies on insect declines, evidence for contrasting patterns in temporal insect trends is growing. Differences in environmental conditions (e.g., climate), anthropogenic pressures (e.g., land-use and climate change), and insect community composition may drive contrasting trends. With increasing elevation, these factors change quickly, which makes elevational gradients an ideal study case to disentangle their roles for differences in temporal trends. We thus analysed 2.8 million moth records collected in Switzerland. Fifty-year trends (1972–2021) depended on local conditions and insect community composition: moth abundance, richness and biomass at low elevation decreased but increased at high elevation. These changes mainly concerned cold-adapted, mono- and oligophagous, and pupal overwintering species, which shifted their ranges upwards. Our results point to climate change but also intensive land use and light pollution as drivers of moth community changes and suggest that high-elevation habitats as refugia could be key to sustain moth diversity.

Climate change is increasing the magnitude and frequency of precipitation extremes. Consequently, grassland community dynamics are destabilising and becoming harder to predict since models typically simulate long-term (asymptotic) behaviour, potentially neglecting short-term (transient) behaviour. Here, we use cover data from an experiment performed over 8 years to model short- and long-term responses of three functional groups (grasses, legumes, and non-leguminous forbs) to precipitation extremes. We use Integral Projection Models (IPMs) and pseudospectral theory to track transient grassland community dynamics driven by response lags and interannual shifts. We show that the cover-class structure and inter-cover-class interactions of functional groups make them transiently unstable but asymptotically stable, that is, disturbances are initially amplified before eventually dissipating. We also show that grasses dominate under irrigation, while legumes and forbs dominate under drought. We demonstrate that the pseudospectra of IPMs enable computationally and data-wise inexpensive assessment of whether transient dynamics drive community responses to disturbances.

Within-sex phenotypic variation can arise through co-option of sexual differentiation mechanisms. Recently, several such cross-sexual-transfer traits have been identified, but we lack a mechanistic understanding of their geographic variation, environmental influences, and phenotypic integration with other traits. Male Polyommatus icarus butterflies are blue, whereas female wing coloration varies from brown to blue. Here, we show that female wing colour varies in a geographic mosaic, with the spring generation being bluer than the summer generation. Laboratory experiments revealed that females developed both bluer wings and increased phenotypic integration between the amount of blue and total wing area at low temperature, qualitatively matching differences between spring and summer generations. Scanning electron microscopy revealed that female and male colour develop through similar mechanisms, supporting the cross-sexual-transfer hypothesis. Our study establishes a promising study system on cross-sexual-transfer and a solid foundation for research on the fitness consequences and evolutionary history of this trait.

Microbial transmission is hypothesised to be a major benefit of sociality, facilitated by affiliative behaviours such as grooming and communal nesting in group-living animals. Whether microbial transmission is also present in animals that do not form groups because territoriality limits interactions and prevents group formation remains unknown. Here, we investigate relationships among gut microbiota, population density and dynamic behavioural and spatial measures of territoriality in wild North American red squirrels (Tamiasciurus hudsonicus). Periods of high population density predicted population-level gut microbial homogeneity but individual-level diversification, alongside changes in obligately anaerobic, non-sporulating taxa indicative of social transmission. Microbial alpha-diversity increased with more frequent territorial intrusions, and pairs with stronger intrusion-based social associations had more similar gut microbiota. As some of the first evidence for social microbial transmission in a solitary system, our findings suggest that fluctuations in density and territorial behaviours can homogenise and diversify host microbiomes among otherwise non-interacting animals.

Despite their importance for forest biodiversity and functioning, little is known about the responses of south European understory herbs to climate change. We used a translocation experiment in southern and central Europe to unravel the short-term effects of macroclimatic (elevation and latitude) and microclimatic conditions (open vs. dense forests, forest edge vs. core position) on plant survival, flowering and traits in eight understorey specialists. Forest density was the main driver of survival, with positive effects in the warm and water-limited southern region and negative effects in the northern oceanic region. Forest position had weaker effects, influencing survival, growth and SLA in contrasting ways at the two latitudes. Most species flowered beyond their northern limit, suggesting the ability for reproduction at higher latitudes. Macroclimate effects on forest herbs interact with forest density, influencing their performance and suggesting complex responses to climate change. Increased vulnerability is expected in relatively open and warmer forests.