Ecology Letters最新文献

Herbivores are commonly classified as host specialists or generalists for various purposes, yet the definitions of these terms, and their intermediates, are often imprecise and ambiguous. We quantified host breadth for 240 non-native, tree-feeding insects in North America using phylogenetic diversity. We demonstrated that a partitioning of host breadth: (1) causes 67% of non-native insects to shift from a generalist to specialist category, (2) displays a reduction in host breadth from the native to introduced range, (3) identifies an inflection point in a model predicting the likelihood of non-native insect ecological impact, with a corresponding change in behaviour associated with specialists versus generalists, and (4) enables three models for strong prediction of whether a non-native forest insect will cause high impacts. Together, these results highlight the primacy of how herbivore host recognition and plant defences mediate whether novel host interactions will result in high impact after invasion.

Ecological and evolutionary questions addressing diversity-environment relationships have been evaluated almost entirely in geographic space, yet most hypotheses are formulated in terms of environmental conditions. Recent examples evaluating macroecological patterns directly in environmental space suggest that such refocusing provides different perspectives on the mechanisms driving broad-scale patterns of diversity. Yet, we lack both conceptual frameworks and targeted studies to fully evaluate the potential contribution of such a refocus. Here, we focus on the concept of environmental space by briefly reviewing its use in ecology and evolution and suggesting avenues for further development. We encourage a re-evaluation of hypotheses and frameworks that have dominated ecological theory since the foundations of ecology with a very simple shift in the lens, that is, from geographical to environmental space. Focusing on environmental space also provides a crucial lens for climate change research, enabling a comprehensive evaluation of biodiversity dynamics and offering a holistic view of the interplay between species and their evolving environments. This shift enhances our ability to predict and adapt to future changes, enriching our understanding of biodiversity beyond more commonly done geographic analyses.

Human activities have caused significant changes in animal abundance, interactions, movement and diversity at multiple scales. Growing empirical evidence reveals the myriad ways that these changes can alter the control that animals exert over biogeochemical cycling. Yet a theoretical framework to coherently integrate animal abundance, interactions, movement and diversity to predict when and how animal controls over biogeochemical cycling (i.e., zoogeochemistry) change is currently lacking. We present such a general framework that provides guidance on linking mathematical models of species interaction and diversity (network theory) and movement of organisms and non-living materials (meta-ecosystem theory) to account for biotic and abiotic feedback by which animals control biogeochemical cycling. We illustrate how to apply the framework to develop predictive models for specific ecosystem contexts using a case study of a primary producer–herbivore bipartite trait network in a boreal forest ecosystem. We further discuss key priorities for enhancing model development, data–model integration and application. The framework offers an important step to enhance empirical research that can better inform and justify broader conservation efforts aimed at conserving and restoring animal populations, their movement and critical functional roles in support of ecosystem services and nature-based climate solutions.

Identifying species with disproportionate effects on other species under press perturbations is essential, yet how species traits and community context drive their ‘keystone-ness’ remain unclear. We quantified keystone-ness as linearly approximated per capita net effect derived from normalised inverse community matrices and as non-linear per capita community biomass change from simulated perturbations in food webs with varying biomass structure. In bottom-heavy webs (negative relationship between species' body mass and their biomass within the web), larger species at higher trophic levels tended to be keystone species, whereas in top-heavy webs (positive body mass to biomass relationship), the opposite was true and the relationships between species' energetic traits and keystone-ness were weakened or reversed compared to bottom-heavy webs. Linear approximations aligned well with non-linear responses in bottom-heavy webs, but were less consistent in top-heavy webs. These findings highlight the importance of community context in shaping species' keystone-ness and informing effective conservation actions.

The difficulties in obtaining species-level abundance estimates of marine larvae have hindered comparisons of diversity across life stages, severely limiting our knowledge of how adult diversity is maintained. To explore factors shaping diversity across life stages, we surveyed adult coral reef fishes, compiled data on their ecological and life history traits and paired these with a unique dataset of species-level larval abundances. Relative larval abundance was more even compared to adults and matched random expectations, whereas the adult community was markedly uneven and less functionally diverse, suggesting species filtering effects. While adult abundance was positively linked to larval abundance, species size and diet altered this association, with larger and non-planktivorous adults being less abundant than expected from their larval supply. Our results illustrate that while larval supply is important in determining adult taxonomic and functional diversity, post-larval processes increase the numerical dominance of particular species, thus reducing overall diversity.