Wetland Resilience and Self-organization
Our work in wetlands is focused on the ability of these systems to withstand disturbance. Resilience is a concept that describes the capacity of an ecosystem to persist in its present state in the face of forces such as floods, droughts, fires, and pest outbreaks. The term is used in different ways in the ecological literature: in some cases, resilience refers to the rate at which a system returns to its prior equilibrium. Our work focuses on another definition of resilience, which is the size of disturbance that a system can withstand without switching to some other state. This definition of resilience is intimately tied to the concepts of self organization and tipping points, and is an organizing idea for how we think about wetlands.
Dr. Heffernan's interest in wetland resilience originates in his dissertation work, which demonstrated that wetland formation and persistence is a function of the ability of plants to stabilize and armor sediments during large floods. Our lab's more recent work has addressed how the spatial patterning of the Everglades ridge-slough landscape responds to changes in depth and hydroperiod (mostly changing due to active water management in south Florida). This ongoing work includes extensive spatial surveys of microtopography, water depth, and vegetation, as well as models of spatial processes.
Two new projects in the lab build on these ideas of resilience and self-organization in new settings. First, we are just beginning a study of Big Cypress Preserve, a limestone landscape adjacent to the ridge-slough in the Everglades. The Big Cypress landscape is a mosaic of isolated wetlands, grasslands, and pine forests. The core observation that motivates our proposal is that the Cypress wetlands appear to be regularly spaced. This sort of regular pattern occurs in dryland vegetation, in peatlands (including the nearby Everglades) and elsewhere, and is thought to arise from feedbacks that are spatially-dependent. Basically, organisms improve the environment in their immediate vicinity, but that has the effect of making more distant locations unsuitable. In Big Cypress, we think that cypress trees essentially capture water from the surrounding landscape by dissolving the limestone bedrock and creating wetland depressions. Pretty smart! Testing this core hypothesis, and all of its pieces, requires an interdisciplinary team. My colleagues at UF, who are going to do most of the field work, include ecohydrologists, soil scientists, and organic and inorganic geochemists. Brad Murray and I are in charge of developing a model of this landscape.
Anna Braswell, a PhD student in the lab, is interested in understanding the broad-scale spatial distribution of coastal wetlands, and whether those patterns have signatures of local feedbacks. We have a pending proposal to do this work with Marco Marani, Brad Murray, and Matt Kirwan at VIMS.
Dr. Heffernan's interest in wetland resilience originates in his dissertation work, which demonstrated that wetland formation and persistence is a function of the ability of plants to stabilize and armor sediments during large floods. Our lab's more recent work has addressed how the spatial patterning of the Everglades ridge-slough landscape responds to changes in depth and hydroperiod (mostly changing due to active water management in south Florida). This ongoing work includes extensive spatial surveys of microtopography, water depth, and vegetation, as well as models of spatial processes.
Two new projects in the lab build on these ideas of resilience and self-organization in new settings. First, we are just beginning a study of Big Cypress Preserve, a limestone landscape adjacent to the ridge-slough in the Everglades. The Big Cypress landscape is a mosaic of isolated wetlands, grasslands, and pine forests. The core observation that motivates our proposal is that the Cypress wetlands appear to be regularly spaced. This sort of regular pattern occurs in dryland vegetation, in peatlands (including the nearby Everglades) and elsewhere, and is thought to arise from feedbacks that are spatially-dependent. Basically, organisms improve the environment in their immediate vicinity, but that has the effect of making more distant locations unsuitable. In Big Cypress, we think that cypress trees essentially capture water from the surrounding landscape by dissolving the limestone bedrock and creating wetland depressions. Pretty smart! Testing this core hypothesis, and all of its pieces, requires an interdisciplinary team. My colleagues at UF, who are going to do most of the field work, include ecohydrologists, soil scientists, and organic and inorganic geochemists. Brad Murray and I are in charge of developing a model of this landscape.
Anna Braswell, a PhD student in the lab, is interested in understanding the broad-scale spatial distribution of coastal wetlands, and whether those patterns have signatures of local feedbacks. We have a pending proposal to do this work with Marco Marani, Brad Murray, and Matt Kirwan at VIMS.