Climate-induced species redistribution

Estimated Net Flow of Burmese Pythons out of the Everglades.

Climate-induced species redistribution

Rapid climate change will result in a global redistribution of biological diversity as species shift their distribution to track suitable conditions. This phenomenon is expected to greatly exacerbate the invasive species crisis by expanding the suitability of introduced species ranges. To understand range shifts in both native and non-native species, considerable emphasis has been placed on landscape connectivity modeling to determine how habitats, climates, and landforms hinder individual movement and influence resulting dispersal paths of species. Currently, the most common approach for quantifying dispersal potential is using spatially explicit landscape resistance models to find optimal movement patterns (via a ‘least cost path’) or flow patterns (via a ‘random walk’ or circuit theory). Despite the utility of these models, they fail to capture important biological processes which have tremendous impact on the result of migrations—movement behavior and mortality. Dispersal represents a substantial source of mortality, especially for invasive species which are highly dispersive. Therefore, failing to consider mortality alongside movement may lead to spurious predictions about species’ cumulative dispersal pathways, which in the context of invasive species management may undermine conservation planning. In response to this problem, Fletcher et al. (2019) developed a framework to successfully parse movement from mortality known as spatially absorbing Markov chain (SAMC). An extension on random walk theory, SAMC uses ‘absorbing’ states to represent mortality associated with suboptimal movements. These processes are modeled in a temporally and spatially explicit framework, meaning that the user may set biologically meaningful timeframes (e.g. 1, 10, or 100 generations) and dispersal distances (e.g., 1 km or 10 km per generation). For these reasons, this framework holds tremendous potential for application in invasive species mapping for risk assessment and conservation planning. Despite this potential, this recently developed framework has only been applied to select model systems. Methods: a) Develop a list of priority invasive species which represent the greatest threat to conservation through expert elicitation and stakeholder interaction and b) model the movement and spread of invasive species using the SAMC framework, c) interpret predicted patterns of movement and determine which landscape features promote or impede the spread of invasive species, and d) compile the information for dissemination to a diverse audience of citizens, stakeholders, managers, and biologists through peer reviewed manuscripts, white papers, and web-based interactive maps and data downloads.

J Alex Baecher
J Alex Baecher
PhD student, Research Assistant

My research interests include landscape ecology and applied conservation of reptiles and amphibians

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