Spatio-temporal co-occurrence patterns of marine molluscan taxa and their potential drivers

Abstract

Ecological communities are complex, often shaped by a multitude of biotic interactions and environmental controls. Competition, which is the interaction among individuals contesting for a finite shared resource, plays a crucial role in determining the composition of these communities. However, a comprehensive understanding of the extent of competitive interactions in marine communities and their environmental drivers still eludes us. In this study, we use modern-day occurrence records and a suite of statistical approaches to gauge the evolutionary outcomes of competition in marine molluscs. We seek to explore the effect of abiotic environmental factors on competition, and propose a new metric to test the extent of competitive interactions using the mean taxonomic distinctness among co-occurring species pairs. This robust metric is not influenced by the sample size or species/genus richness of the studied population. Our key findings show that competition among marine molluscs did not result in the segregation of closely related species over time. While the effect of abiotic factors on competition were found to be context-dependent and inconsistent across classes; Depth, Sea Surface Temperature and Dissolved O2 exerted a considerable control on competition. The cascading effects of climate change warrant further explorations to assess the impact of these factors on competition, owing to their important consequences on biodiversity and community structure.