Identifying abrupt changes in the structure and functioning of systems, or regime shifts, in ecological and social-ecological systems leads to an understanding of relative and absolute system resilience. Resilience science provides a framework and methodology for quantitatively assessing the capacity of a system to maintain its current trajectory or regime. If and when a system’s resilience is exceeded, it crosses a threshold and enters into an alternate regime (or undergoes a regime shift). Univariate indicators (i.e. first through fourth moments) based on bifurcation theory have been used to detect regime shifts on longitudinal data, predominantly using marine fisheries data. Unlike traditional univariate indicators of regime shifts, Fisher Information, a measure of negentropy, may allow for detecting of shifting regime boundaries in space, providing an estimate of ecosystem vulnerability to regime shifts. We use the North American Breeding Bird Survey, an annual, volunteer-driven avian roadside point count program to identify shifting regime boundaries over space and time across the Central Great Plains of the United States. We estimated the vulnerability of Fort Riley military base in Riley, Kansas to regime shifts by examining the proximity of the military base to shifting regime boundaries.
Results/Conclusions
Fisher Information identified poleward shifts of the broad-scale, ecological regime boundaries in the Central Great Plains region of the United States. We identified a broad-scale, shifting, spatial regime in the area surrounding Fort Riley military base that correlates with the Northward range expansion of Eastern Redcedar (Juniperus virginianus). Fort Riley military base maintains grassland habitat via prescribed fire and is a hub of biodiversity yet is embedded within a spatial regime consisting of Eastern Redcedar. Temporally, Fisher information has the potential to provide early warning of impending regime changes. Spatially, Fisher information allows for an objective way of identifying regime boundaries, and tracking changes in those boundaries over time. Fisher information is therefore especially useful for assessing how climate changes affects biogeographical distribution patterns of species and their consequences for resilience, including sudden changes in spatial ecological regimes resulting from these distribution patterns. We use Fisher Information, a measure of negentropy, to detect regime shifts in both space and time using longitudinal bird community abundance data in central North America.