Ecology Letters最新文献

Understanding the mechanisms behind interaction turnover over long-term periods is essential to predict how ecological networks respond to global change. We used a high-resolution dataset of butterfly-plant interactions spanning 13-29 years in seven Mediterranean communities to assess how climate fluctuations and community shifts shape interaction turnover and its components-species turnover and rewiring. Rewiring contributed the most to interaction turnover, but its relative importance declined over time as species loss reduced the pool of shared partners between years. Consequently, species turnover became increasingly influential, even though communities shifted toward butterfly species with generalist traits that promote rewiring. Nevertheless, rewiring intensified in years with stronger temperature fluctuations, when populations experienced greater shifts in phenology and abundance and were more likely to rewire. In the context of biodiversity loss, species turnover increasingly governs interaction dynamics, while the short-term flexibility provided by rewiring may collapse as communities become impoverished.

The global expansion of human activities increasingly exposes wild animals to novel, potentially threatening conditions. Consistent behavioural responses to perceived risk may be detrimental to wildlife, either by limiting foraging opportunities or by overexposing them to lethal hazards. We examine the relationship between risk responses, movement patterns and survival in fan-tailed ravens (Corvus rhipidurus) inhabiting Israel's Dead Sea coastline. We found consistent individual differences assessed through controlled laboratory assays (novel food, objects, environment and foraging near humans) and even stronger consistencies in the wild via GPS-derived movement metrics. While risk-prone ravens remained near tourist sites and travelled less, risk-averse individuals foraged farther towards the edge of their home ranges, avoiding human activity. Further, risk-averse individuals were more likely to survive over extended periods than risk-prone individuals. As anthropogenic change accelerates, variation in consistent risk-taking behaviour could determine individuals' capacity to adapt and survive and consequently shape population composition and persistence.

Trait-based approaches support the mechanistic understanding of individual organism responses to resource availabilities that underlie population and community dynamics. For microbes such as phytoplankton, however, it remains challenging to obtain individual cell traits, particularly in natural communities. Here, we provide a flow cytometry-based approach using a freshwater cyanobacterium Microcystis spp. culture and assessed individual-level trait responses to nitrogen, phosphorus and light limitation and high pCO₂. Then, these responses served as ‘fingerprints’ to describe the main drivers in natural cyanobacterial communities. We observed distinct responses in multidimensional trait space, that is, the integrated phenotype, which differed particularly between nitrogen and light limitation. Notably, cellular contents of the pigments phycocyanin and chlorophyll-a decreased with nitrogen limitation and increased with light limitation, which was confirmed in natural communities. Overall, our results show how individual-trait responses to known environmental conditions can be used to understand natural cyanobacterial population and community dynamics.

Ecological conditions can significantly influence the trade-off between survival, growth and reproduction, driving life-history divergence among populations in different environments. The pace of life syndrome hypothesis (POLS) proposes that additional suites of traits, from physiology to behaviour, adaptively co-evolve with life-history traits along a slow-fast continuum. Using data from 192 studies representing 104 squamate species, we performed phylogenetic meta-analyses testing whether traits vary predictably across elevation within species in accordance with POLS. Results show there is no clear evidence for an overall intraspecific elevational pace-of-life syndrome in squamate reptiles. While high elevation populations had significantly lower body temperatures and larger egg sizes, most traits—including body size, longevity, fecundity and thermal tolerance—exhibited non-significant elevational patterns. Critically, lizards and snakes responded fundamentally differently: snakes showed significant differences in adult female and neonate body size and fecundity across elevation, while lizards showed no significant divergence. Elevation-latitude interactions provide further evidence against a single pace-of-life solution to elevation. Our findings challenge the applicability of POLS theory within species, revealing that life-history evolution is more context-dependent and taxonomically constrained than syndrome-based approaches suggest. These results contribute to growing evidence that universal trait syndromes rarely emerge across environmental gradients in diverse taxonomic groups.

Temporal fluctuations in the environment can promote coexistence via the storage effect, where competing variants are buffered during unfavourable years. In annual plants, this can arise from seed dormancy: seeds remain in the seed bank across years and germinate under suitable conditions. Here, we investigate how plasticity in germination timing (where seeds use environmental cues to adjust when they germinate) affects genetic diversification and ecological speciation. Using eco-evolutionary models, we show that adaptive plasticity readily evolves via genetic associations between germination and fecundity traits, allowing seeds to germinate preferentially in years favourable for reproduction. This enhances temporal niche partitioning and promotes divergence into specialised morphs. Because these morphs germinate in different years, plasticity generates temporal assortative mating and maintains trait associations even without genetic linkage. Our results show that adaptive plasticity and genetic diversification can interact synergistically: predictive germination not only buffers fluctuations but also drives the evolution of biodiversity.

Compositional uniqueness has become increasingly relevant for understanding how local communities contribute to regional biodiversity. The most widely used metric is the Local Contribution to Beta Diversity ($��\text{LCBD}�$), which is typically regressed against environmental predictors. However, $��\text{LCBD}�$ can vary either because of environmental processes that affect the overall variance in community composition, or because communities change directionally along environmental gradients. The latter implies that $��\text{LCBD}�$–environment relationships can strongly depend on how the environment is sampled. To address this issue, we introduce Generalised Dissimilarity Uniqueness Models (GDUM), a framework that embeds effects on community uniqueness within pairwise dissimilarity modelling. GDUMs are consistent with conventional uniqueness models, while explicitly accounting for directional changes in composition. This distinction disentangles directional and non-directional drivers of beta diversity, such as environmental filtering versus stochastic processes. By improving interpretability and generalisability, GDUM is a useful tool for understanding beta diversity patterns and projecting biodiversity responses.

Parasites have repeatedly evolved the ability to modify their host's behaviour to enhance transmission. However, the conditions shaping such host manipulation remain unclear. I conducted a phylogenetic meta-analysis of 207 studies comprising 1635 observations from 82 parasite and 80 host taxa to identify patterns in host manipulation and test ecological and evolutionary drivers of host manipulation in trophically transmitted helminths. Manipulation reliably increased host susceptibility to predation and effects depended strongly on parasite stage: mature parasites consistently enhanced predation susceptibility, whereas immature stages showed little or inconsistent impact. In mixed infections, mature parasites dominated, and manipulation was stronger in the presence of the correct predator. Phylogenetic constraints were minimal, in line with repeated independent origins. The ecological and evolutionary drivers and constraints tested here had only weak or inconsistent effects.