Range shifting species reduce phylogenetic diversity in high latitude communities via competition.

Under anthropogenic climate change, many species are expanding their ranges to higher latitudes and altitudes, resulting in novel species interactions. The consequences of these range shifts for native species, patterns of local biodiversity and community structure in high latitude ecosystems are largely unknown but critical to understand in light of widespread poleward expansions by many warm-adapted generalists. Using niche modelling, phylogenetic methods, and field and laboratory studies, we investigated how colonization of Scotland by a range expanding damselfly, Ischnura elegans, influences patterns of competition and niche shifts in native damselfly species, and changes in phylogenetic community structure. Colonization by I. elegans was associated with reduced population density and niche shifts in the resident species least related to I. elegans (Lestes sponsa), reflecting enhanced competition. Furthermore, communities colonized by I. elegans exhibited phylogenetic underdispersion, reflecting patterns of relatedness and competition. Our results provide a novel example of a potentially general mechanism whereby climate change-mediated range shifts can reduce phylogenetic diversity within high latitude communities, if colonizing species are typically competitively superior to members of native communities that are least-closely related to the colonizer.

Life history trade-offs, the intensity of competition, and coexistence in novel and evolving communities under climate change.

The consequences of climate change for local biodiversity are little understood in process or mechanism, but these changes are likely to reflect both changing regional species pools and changing competitive interactions. Previous empirical work largely supports the idea that competition will intensify under climate change, promoting competitive exclusions and local extinctions, while theory and conceptual work indicate that relaxed competition may in fact buffer communities from biodiversity losses that are typically witnessed at broader spatial scales. In this review, we apply life history theory to understand the conditions under which these alternative scenarios may play out in the context of a range-shifting biota undergoing rapid evolutionary and environmental change, and at both leading-edge and trailing-edge communities. We conclude that, in general, warming temperatures are likely to reduce life history variation among competitors, intensifying competition in both established and novel communities. However, longer growing seasons, severe environmental stress and increased climatic variability associated with climate change may buffer these communities against intensified competition. The role of life history plasticity and evolution has been previously underappreciated in community ecology, but may hold the key to understanding changing species interactions and local biodiversity under changing climates.This article is part of the themed issue 'Human influences on evolution, and the ecological and societal consequences'.

Morphological and geographical traits of the british odonata.

Trait data are fundamental for many aspects of ecological research, particularly for modeling species response to environmental change. We synthesised information from the literature (mainly field guides) and direct measurements from museum specimens, providing a comprehensive dataset of 26 attributes, covering the 43 resident species of Odonata in Britain. Traits included in this database range from morphological traits (e.g. body length) to attributes based on the distribution of the species (e.g. climatic restriction). We measured 11 morphometric traits from five adult males and five adult females per species. Using digital callipers, these measurements were taken from dry museum specimens, all of which were wild caught individuals. Repeated measures were also taken to estimate measurement error. The trait data are stored in an online repository (https://github.com/BiologicalRecordsCentre/Odonata_traits), alongside R code designed to give an overview of the morphometric data, and to combine the morphometric data to the single value per trait per species data.