Habitat destruction and extinction in competitive and mutualistic metacommunities

Because habitat loss is a leading cause of extinction, it is important to i dentify what kind of species is most vulnerable. Here, I use algebraic and graphical techniques to study metacommunity models of weak competition or l ocally facultative mutualism in which species may coexist within patches. B ecause a competition-colonization tradeoff is not required for regional coe xistence of competitors, poor competitors are often regionally rare and mos t prone to extinction, in contrast to results from previous models of stron gly competitive metapopulations. Metacommunities of mutualists can suffer t he abrupt extinction of both species as habitat destruction is increased. T hese highlight the importance of identifying the mechanisms by which specie s coexist to predict their response to habitat loss.