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Tracking shifting range margins using geographical centroids of metapopulations weighted by population density


Watts, MJ and Fordham, DA and Akcakaya, HR and Aiello-Lammens, ME and Brook, BW, Tracking shifting range margins using geographical centroids of metapopulations weighted by population density, Ecological Modelling, 269 pp. 61-69. ISSN 0304-3800 (2013) [Refereed Article]

Copyright Statement

Copyright 2013 Elsevier

DOI: doi:10.1016/j.ecolmodel.2013.08.010


Spatially explicit metapopulation models are being used with increasing frequency to forecast changes in species’ abundance in response to future climate and other environmental changes. However, to date, they have not quantified shifts in the margins of the metapopulation range – an important dynamic for understanding species responses to climate change. Here we describe a method for calculating shifts in a metapopulation's range-margin based on the geographical centroid of spatially distributed patches, where the population abundance of each patch or each landscape grid cell is used to weight its geographical (XY) coordinate. We evaluated our approach against a detailed virtual example and two real-world applications (threatened mountain hare in Britain and invasive European rabbits in Australia). We also investigated smoothing techniques to better portray overall trends in range changes through time. These procedures were implemented in a new user-friendly software tool, which can process the output file of the popular RAMAS Metapop software. We develop a scenario analysis to show how our weighted-centroid approach can be used to recommend species management options that are most important to long-term population viability (e.g., to choose between increasing connectivity, habitat quality or translocation) under different demographic scenarios. We show that calculating a smoothed time series of weighted centroids from a spatially explicit metapopulation model provides: (i) a useful way to identify the demographic momentum, or momentum of population shift, of the metapopulation (rather than just spatial aggregation or individual-patch behaviour) of a species through geographic space in response to climate change; and (ii) an informative metric of range movement that complements predictions of change in range area or total population size, and extirpation or founding of patches.

Item Details

Item Type:Refereed Article
Keywords:climate change, coupled niche-population model, population viability analysis, population and weighted centroids, range dynamics, species distribution
Research Division:Environmental Sciences
Research Group:Environmental management
Research Field:Conservation and biodiversity
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Understanding climate change
Objective Field:Climate change models
UTAS Author:Brook, BW (Professor Barry Brook)
ID Code:97961
Year Published:2013
Web of Science® Times Cited:10
Deposited By:Biological Sciences
Deposited On:2015-01-22
Last Modified:2017-10-30

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