Dispersal and resilience

In general, I am interested in the factors that promote resilience in the face of disturbance and climate change. Working in the Canadian subarctic provided an interesting system to ask about the role of regional dispersal in maintaining ecosystem function and community diversity due to the high level of dispersal found in the region. Many systems are dispersal limited, but in the wetlands of the north 40% of the land is covered with water and there is likely very high dispersal of aquatic organisms between lakes. First, we examined spatial patterns of community composition and environmental variables and found strong signals of high dispersal rates (Symons et al. 2014). I then conducted an experiment to examine how dispersal influenced ecosystem function and recovery after a nutrient and/or salt addition.

Theoretical and empirical studies have suggested that dispersal of individuals from a regional species pool may enable communities to adapt to environmental change. For species to track changing environmental conditions, dispersing species must be able to establish in the resident community (i.e., communities must be invasible) to generate variation, allowing a dynamic response to environmental change. Using a mesocosm experiment I demonstrated that  disturbance increases community invasibility initially, but the invasibility of communities decreases post-disturbance (Symons and Arnott, 2014). Additionally, regional dispersal helped to maintain ecosystem function in the face of environmental change, though these communities were relatively resilient to increases in salinity and nutrients (Symons and Arnott, 2013).

Project timeline: This project was completed between 2010 and 2012 when I was a MSc student in Shelley Arnott's lab at Queen's University.

Papers:

Symons, C.C. and Arnott, S.E. 2013. Regional zooplankton dispersal provides spatial insurance for ecosystem function. Global Change Biology 19: 1610–1619. PDF.

Symons, C.C. and Arnott, S.E. 2014. Timing is everything: priority effects alter post-disturbance invasibility.  Ecology and Evolution 4: 397-407. PDF.

Symons, C.C., Pedruski, M., Sweetman, J.N. and Arnott S.E. 2014. Spatial, abiotic and biotic determinants of zooplankton community composition in Subarctic tundra ponds in Wapusk National Park, Canada. Arctic, Antarctic and Alpine Research 46: 159-190. PDF.