Apparent signal of competition limiting diversification after ecological transitions from marine to freshwater habitats

作者：Betancur R Ricardo^*; Orti Guillermo; Stein Ariel M; Marceniuk Alexandre P; Pyron R Alexander

来源：Ecology Letters, 2012, 15(8): 822-830.

DOI：10.1111/j.1461-0248.2012.01802.x

• Adaptive radiation
• Ariidae
• disparification
• diversification
• ecological opportunity
• freshwaters
• habitat transitions
• marine
• morphological evolution
• phylogeny

Adaptive radiations are typically triggered when a lineage encounters a significant range of open niche space (ecological opportunity), stemming from colonisation of new areas, extinction of competitors or key innovations. The most well-known of these is the colonisation of new areas, through either dispersal into new regions or the invasion of novel ecological regimes. One aspect of ecological opportunity that has rarely been studied, however, is the extent to which pre-existent competitors act to limit diversification in newly colonised adaptive zones. Herein, we show that in multiple geographically independent invasions of freshwaters by marine Sea Catfishes (Ariidae), rates of both morphological disparification and lineage diversification are inversely related to the presence and diversity of other freshwater fish lineages. Only in one region (Australia-New Guinea) with an otherwise depauperate freshwater fauna, has an ariid invasion gained any substantial traction. This is true at both regional and community scales, suggesting that competitive constraints may be an important factor regulating adaptive radiation.

• 出版日期2012-8