Ecology Letters最新文献

Freezing tolerance plays a pivotal role in shaping the distribution and diversification of organisms. We investigated the dynamics of adaptation to climate and potential trade-offs between stem freezing tolerance and growth rate in 48 Quercus species. Species from colder regions exhibited higher freezing tolerance, lower growth rates and higher winter-acclimation potential than species from warmer climates. Despite an evolutionary lag, freezing tolerance in oaks is closely aligned with its optimal state. Deciduous species showed marked variability in freezing tolerance across their broad climatic range, while evergreen species, confined to warm climates, displayed low freezing tolerance. Annual growth rates were constrained in all deciduous species, but those that evolved in warm latitudes lost freezing tolerance, precluding a trade-off between freezing tolerance and growth. We provide evidence that the capacity to adapt to a wide range of thermal environments was critical to adaptive radiation and the current dominance of the North American oaks.

It is generally accepted that small birds cannot eat large fruits and that highly frugivorous species prefer lipid-poor ones (morphological and nutritional trait-matching). Yet, it is unclear if these rules operate globally and if their strength varies with latitude and on islands. This could have important functional implications for the degree of complementarity and irreplaceability of birds. We analyse avian frugivory in 59 communities across the globe and show that trait-matching is widespread. The strength of morphological trait-matching increased with latitude, and especially on islands, leading to high complementarity between large and small birds. However, whether this resulted in irreplaceability depended on the range of fruit sizes available in the community. Nutritional trait-matching was also common, but did not lead to complementarity or irreplaceability because birds with contrasting diets did not show opposite responses to lipid-poor fruits. We show that trait-matching is pervasive, but its functional consequences are complex.

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.