Nischbreddens långsamma evolution och dess betydelse för sårbarhet hos ekologiskt specialiserade hackspettar (Picidae)

Sammanfattning

Ecological specialization is highlighted in ecology and evolutionary biology as a factor influencing species distribution and vulnerability. Species with broad ecological tolerances and the ability to utilize a wide range of resources are better able to survive across larger geographic ranges. In contrast, species with narrow ecological niches depend on a more limited selection of resources and habitats. This distinction makes it possible to measure or determine differences in the breadth of resource use between species. The aim of the study was to investigate how variation in niche breadth within the woodpecker family (Picidae) affects their vulnerability to extinction, as well as how rapid changes in niche breadth can evolve. Compared to other birds, woodpeckers exhibit specific needs regarding resources and structural habitat requirements; they therefore constitute a suitable test group. Using an AI-model, niche breadth was categorized for 147 species based on information about habitat and resource use. The relationship between niche breadth and threat status was analyzed in conjunction with phylogenetic analyses of transition rates between different categories of niche breadth and phylogenetic signal. We found that species with more specialized niche breadth tend to be more vulnerable and face a greater risk of extinction than generalists. It was observed that this trait appears to be relatively phylogenetically conserved. Our MK-models showed that niche breadth evolves at varying rates depending on the direction and category of niche breadth. The results support our hypothesis that ecological specialization increases species’ vulnerability to extinction and suggests that specialized woodpeckers may have a limited ability to rapidly adapt to changing environmental conditions.