Stability is an important topic across ecological disciplines, and we make one very important distinction: in ecological studies, stability does not equate with static or stationary. Ecological stability is dynamic in nature, whether it is population oscillations such as the predator/prey cycle or landscapes that require disturbance dynamics to remain stable over time. The Everglades ridge and slough landscape (RSL) has been stable over millennia, despite dynamic environmental conditions and anthropologic disturbance. The pattern has persisted despite lack of flow and despite the fact that there have been temporal fluctuations in the local scale vegetation communities. This leads to two questions: what are the processes involved in local dynamics and what is the potential feedback of local effects on landscape stability? We answer these questions through an evolving set of models: one to determine the ecological processes involved in local stability of the RSL system, and a second to explore the local dynamics that may cause landscape stability.
Results/Conclusions
Our models indicate long term, local hydrology and edaphic factors control the small scale shifts between ridges and sloughs and that these dynamics, when scaled up to the landscape, demonstrate a stable pattern that is reflected in situ. How could a dynamic patch yield a stable system? It is the environmental diversity (or local microtopography) of the ridge patch that allows the local populations to persist through dynamic seasonal and climactic hydrology. Patches with > 20 cm within-patch microtopography demonstrate higher production and an increasing amount of peat production or carbon storage than those with less elevational differences. This environmental heterogeneity creates local refugia during non-ideal growing conditions (both too wet and too dry) for ridge vegetation and acts as a shock absorber for disturbance. It is critical to understand how the relationships between local microtopography and biological factors can affect landscape level processes and external mechanisms just as they are also affected by those larger factors. Perhaps by examining the local feedbacks from landscape processes, one would be able to determine the resilience of the landscape to future disturbances such as climate change.