Ecosystems are shaped not only by internal dynamics, but also by connectivity with other ecosystems, with signals transported among ecosystems through space and time. Potential or structural connectivity is established by spatial and temporal configuration of donor and recipient ecosystems. Functional connectivity is then realized by vectors of wind, water, and animal movement that transport energy, material, and information currencies. Feedbacks between potential and functional connectivity result in dynamic patterns of transport, and predicting the outcomes of dynamic connectivity is critical to understanding ecosystems and the services they provide. A rich history of research has generated examples highlighting the nature and significance of connectivity for population, community, ecosystem, and landscape ecology. However, a general framework that offers predictive capability regarding the role of connectivity in ecosystems is still emerging. Questions remain regarding the relative roles of the connected ecosystems, such as the nature of contrasts between them, and the attributes of transport vectors, including their routing, timing, and magnitude. Sites within the US Long-Term Ecological Research Network (LTER) have addressed these questions with long-term monitoring of energy and material fluxes and animal movement at local and regional scales and experiments simulating or manipulating connectivity.
Results/Conclusions
LTER research has demonstrated the role of connectivity in shaping organismal dynamics and nutrient cycling at multiple scales, and has uncovered how changing connectivity and novel flowpaths will alter ecosystem dynamics. In the Arctic, hydrologic connectivity across terrestrial and aquatic ecosystems shapes the composition of microbial communities, with terrestrial ecosystems providing inocula to lakes and streams. Gene or propagule flow among reef ecosystems results in long-term stabilization or resilience of ecosystems to perturbations. Long-term studies have also captured changes in connectivity. For example, in the Everglades, increased delivery of marine resources to freshwater wetlands occurs due to saltwater intrusion, and in Antarctica, glacial melt introduces novel hydrologic flowpaths to dry valley ecosystems that enhance biodiversity and rates of biogeochemical cycling. By networking across sites and drawing on expertise from multiple disciplines, the LTER network might contribute to developing predictive models addressing connectivity from local to continental scales.