Analyzing the ecological diversity of the world's mammals and birds

Abstract

Global biodiversity loss threatens the continued provision of ecosystem function and ecosystem services, upon which we all rely. Biodiversity is multidimensional, encompassing taxonomic, phylogenetic and ecological diversity; yet taxonomic diversity has received the majority of research effort. In this thesis, I focus on the ecological diversity of the world’s mammals and birds, based on species traits, as ecological diversity strongly relates to species’ ecological roles and to the functions species perform. I show that mammals and birds are ecologically comparable and provide complementary and comparative macroecological perspectives. I find a global trade-off between the similarity of species roles (functional redundancy) and the breadth of roles across taxa (functional dispersion) (Chapter 2). I also demonstrate different contributions of mammals and birds to functional redundancy and functional dispersion, and unique geographic patterns of redundancy and dispersion by including both taxa. I then show that the ecological diversity of mammals and birds is structured by life-history speed (fast-slow) and body mass (small-large) in one dimension, and diet (invertivore-herbivore) and habitat breadth (generalist-specialist) in the other dimension (Chapter 3). Using a probabilistic extinction framework, I predict a greater decline in ecological diversity than expected at random over the next century, shifting the mammal and bird species pool towards small, fast-lived, highly fecund, insect-eating, generalists. I also quantify ecological distinctiveness for mammals and birds (Chapter 4), identifying conservation priority species with potentially irreplaceable ecological roles. I find that high ecological distinctiveness is associated with both highly threatened species, such as Amsterdam Albatross and Sumatran rhinoceros, and non-threatened hyper-generalists, such as Lesser Black-backed Gull and wild boar. Finally, using structural equation models, I determine a strong role of trophic interactions for global patterns of mammalian species richness, but a surprisingly weak role for functional diversity and phylogenetic diversity (Chapter 5). My thesis demonstrates that ecological diversity can offer novel and complementary insights and can inform the prioritization of conservation actions. Overall, I recommend maintaining the complex ecological diversity of the world’s mammals and birds as a fundamental goal for conservation.

More information

Identifiers

ORCID for Felix Eigenbrod: orcid.org/0000-0001-8982-824X

Catalogue record

Export record