How network analysis could help in the study of invasions of non-native mollusc species

Abstract

In this context, non-native mollusc species (NNMS) are huge threats to entire terrestrial, freshwater and marine ecosystems. Usually as a result of human commercial activities, NNMS are introduced into novel areas and rapidly expand by using a variety of dispersal vectors and pathways, including river systems, sea-routes and land-routes. In South America, NNMS represent a constant concern for conservation and a number of studies are being developed to tackle their invasions (e.g. Darrigran et al., 2020, 2022). These studies show that the diverse ecosystems of the South American continent suffer particularly from this problem. Darrigran et al. (2020) identified four hotspots in South America that serve as entry points and distribution foci for NNMS in the continent: Subtropical-Atlantic, Northern Andes, Central Andes and Southern Andes. Now we present a new approach, modelling the dispersal potential of NNMS in the continent by adapting methods originally developed for the study of social networks. We conceptualise the South American continent as composed of a set of nodes that are connected to each other by a series of edges that represent the main dispersal vectors: geographical proximity, rivers, roads, railways etc. The result is a model of the connectivity pattern of the continent (Fig. 1).