What will PIE marshes look like in the future?
The system as we know it today is facing a number of challenges stemming from the external drivers of sea level rise, human activities, and climate change. For PIE, those challenges are:
- Accelerated rates of sea level rise, currently 4mm y-1 compared to the 100 year average of 2.8 mm y-1;
- Sediment starvation, from the damming of rivers and streams in the watershed by humans as well as by beavers, whose populations are now protected and flourishing;
- Species immigration and emigration, with sea surface temperatures in the Gulf of Maine having risen at 3 times the global average over the last 30 years.
We anticipate large changes in the geomorphology of the marsh and estuary over the next century and beyond, with the current predominantly high-elevation marsh, dominated by Spartina patens, changing to a lower elevation, more frequently flooded marsh dominated by Spartina alterniflora (depicted right).
Our current research will examine the effects of the external drivers on the mechanisms of geomorphic change, and the impacts they will have on ecosystem structure and function. We will examine the connections and feedbacks between the external drivers and internal responses, as well as interactions among the internal processes. We have organized our thinking by focusing on specific components within the overall conceptual model, highlighted below, as well as the processes and interactions most relevant to them:
and Primary Production
and Food Webs