Beyond environmental drivers: the role of biotic interactions in driving top predators' distribution and abundance

Abstract

Over the past 10 years, Species Distribution Models have become commonplace in the studies of biogeography, conservation biology, ecology, and climate change. However, most studies applying SDMs mainly quantify species-environment relationships and usually omit functional roles of species, biotic interactions and resource-consumer dynamics. Within this context, this thesis aimed to advance in the understanding of how biotic and abiotic factors shape species distribution and abundance by using the community of top predators of the Bay of Biscay as case study. To address this overall objective, we carried out three different studies that aimed to answer the following specific research questions:- To identify the main environmental and biotic drivers of species co-occurrences within the top predators-prey community of the Bay of Biscay. - To understand how co-occurring top predators share the environmental and trophic niche.- To define the role that prey, climatic and oceanographic variables in driving the spatio-temporal patterns of a highly mobile top predator.- To determine the relative importance of biotic and environmental drivers explaining the abundance and distribution of top predators.By this means, this thesis intended to obtain a more comprehensive understanding of the drivers governing the assemblage of top predators and a better knowledge of ecosystem functioning of the BoB.