The project has been articulated around four work packages. In the first work package I studied the relationship between species diet breadth and species range size. The analyses resulted in the publication of a scientific article in the high impact journal 'Global Ecology and Biogeography' entitled: 'Climate or diet? The importance of biotic interactions in determining species range size'. This study offered new insights into the importance of biotic interactions in determining species spatial distributions. We found that species with larger ranges have more interactions locally and they are also able to interact with a larger diversity of species across sites, resulting in a larger number of interactions at continental scales. I organised a symposium at the International Biogeography Society 11th Biennial Conference, Prague, January 2024 to disseminate and further develop the results of this project.
In the second work package, I analysed the interplay between the spatial distribution of species and their biotic interactions and the influence of the spatial scale of observation. For that, I developed a theoretical framework able to link the distribution of species across space and their biotic interactions, and tested the theoretical predictions with empirical data extracted from the literature. This resulted in a scientific article published in Nature Ecology and Evolution entitled: 'Power laws in species’ biotic interaction networks can be inferred from co-occurrence data'. This work elucidates the importance of the interplay between the spatial distribution of species and their biotic interactions for the assembly of ecological communities. We found that only 20% of co-occurrences correspond to actual interactions. Moreover, we showed that super-generalist species, possessing both broad environmental tolerance and diet generality, interact with a disproportionately large number of the species they co-occur with, leading to ecological networks with scale-free power law degree distributions. These findings represent an important advancement in understanding community assembly while providing unexpectedly realistic predictions of biotic interaction networks based on species co-occurrence information alone. This work has been presented in several national and international seminars.
The third work package was devoted to the analyses of the geographical variation of the relationship between species diet breadth and range size and the influence of different environmental variables. This work package led to the exhaustive examination of the literature to understand the differences across biomes in the relationship between species diet breadth and range size, and to identify the environmental factors affecting biotic interactions. All the knowledge acquired during the literature examination resulted in a review paper that is close to submission. In this review paper we identify the mechanisms by which biotic interactions affect large scale biogeographical patterns, how environmental gradients affect biotic interactions and how, in turn, these biotic interactions affect the environmental factors.
The fourth work package was focused around the development of a theoretical framework and causality inference of the relationship between diet breadth, range size and the environment. This work package has nourished several of the other work packages. For the proper development of this work package I received formation on species distribution modelling and machine learning techniques. I developed null model analyses that allowed us to infer causality in the relationship between species biotic interactions and their range size, and I developed a theoretical framework that establishes the basis of the relationship between species biotic interactions and their spatial distribution. I have also expanded this theoretical framework to understand how habitat loss will affect the relationship between species distributions and their biotic interactions.
