The increasing pressure of climatic change and anthropogenic activities is predicted to have major effects on ecosystems around the world. With their fragility and sensitivity to hydrologic shifts and land-use changes, wetlands are among the most vulnerable of such ecosystems. Focusing on the Everglades National Park, we here assess the impact of changes in the hydrologic regime, as well as habitat loss, on the spatial configuration of vegetation species. Because the current structuring of vegetation clusters in the Everglades exhibits power-law behavior and such behavior is often associated with self-organization and dynamics occurring near critical transition points, the quantification and prediction of the impact of those changes on the ecosystem is deemed of paramount importance. We implement a robust model able to identify the main hydrologic and local drivers of the vegetation species spatial structuring and apply it for quantitative assessment. We find that shifts in the hydropatterns will mostly affect the relative abundance of species that currently colonize specific hydroperiod niches. Habitat loss or disruption, however, would have a massive impact on all plant communities, which are found to exhibit clear threshold behaviors when a given percentage of habitable habitat is lost.climate change impacts | ecohydrology | ecology | habitat vulnerability A s the interest surrounding wetlands and their fate has grown throughout the last decades, the impact of the increasing anthropogenic and climatic changes on their delicate ecosystem, and in particular on their vegetation dynamics, has been the subject of numerous studies (1-5). It was shown that the spatial organization of vegetation often arises from the interplay between local endogenous dynamics and global exogenous forces (6-9). In the Everglades National Park (ENP), in particular, such interplay is responsible for power-law clustering of vegetation species (10). Moreover, the ENP is a cradle where a large variety of rare and endangered species coexist within a fragile equilibrium, and the awareness of its importance has drawn attention to the extent that it is the focus of one of the most expensive restoration projects ever attempted (11-13). With these premises, it is of paramount importance to understand and quantify the potential impacts of habitat changes on the vegetation structuring of the Everglades ecosystem.
ResultsThe modeling framework adopted in this study, which reveals the feedback between vegetation structures and hydrologic forces by incorporating the effects of exogenous drivers (i.e., hydropatterns) and endogenous mechanisms of plant interactions, was successfully used as a diagnostic tool for the analysis of the spatial configuration of plant communities in wetlands, with specific focus on the power-law clustering of vegetation patterns in the Everglades (10) (Materials and Methods). Such a modeling framework is based on a cellular automaton scheme ( Fig. S1 and SI Materials and Methods) applied over a 40-× 40-m study grid covering...