Stable states are thought to represent alternative assemblages of species that may exist in stable equilibrium over time. Such states are defined as discrete temporal or spatial patterns in abundance of resident species. Theory predicts that shifting from one stable state to another may be facilitated by perturbations that may be either natural, anthropogenic or a combination of both. The Pascagoula River in southeastern Mississippi is the largest remaining un-impounded river system in the contiguous United States with a discharge of over 2.4 cu mi per year.
Results/Conclusions
Examination of long term fish assemblage data show that the Pascagoula River, and it’s two major tributaries (Leaf and Chickasawhay Rivers) have been dominated by five abundant taxa that comprise 71% of individuals sampled. Within the last five years, a change in the Pascagoula River (but not Leaf and Chickasawhay) was seen to an alternate assemblage where three different taxa dominate (67% of assemblage). Thus, a shift in stable states seems to have occurred in one portion of the drainage but not the other. We explore potential drivers of this shift and whether or not it may in fact be stable.