New ideas for improving corridor models

fisher_movement_copyrightConservation managers promote landscape corridors as a tool to facilitate animal movement across fragmented landscapes. Yet, while corridor design has received much attention in recent years, few studies have used independent field data to empirically test whether animals use corridors as predicted (e.g. Gillies and St. Clair 2008).

In a recent study that addresses this limitation in corridor science, Scott LaPoint and colleagues recently evaluated the performance of three corridor models in predicting animal movement. To do this, the authors tracked fisher (Martes pennanti) movements in central New York State to identify landscape corridors following three methods: two cost-based models that do not explicitly use movement data (least-cost path analysis and circuit theory), and one movement-based model using high-resolution GPS tracking data. Using camera traps, the authors then tested whether there were higher detection rates of fishers and other mammals within these corridors compared to the surrounding landscape.

The authors present a number of interesting results. First, by analyzing radio-tracking data, they found that corridors may be an individual-based behavioral adaptation to landscape processes. Second, corridors identified using movement data had consistently higher detection rates compared to the surrounding landscape, both for fishers and other mammals. While more research is needed to confirm this trend, such a result suggests that a single species can potentially be used as surrogate to identify corridors for multiple taxa, at least when using movement-based models. Third, detection rates along corridors identified using cost-based models were often lower compared to the surrounding landscape. This is a key result – despite their popularity, cost-based models may in fact be least effective in identifying landscape corridors. One reason why cost-based models fail to detect corridors (at least for fishers) may be that corridors had a different land cover composition than home ranges, making it a challenge to model landscape resistance as a function of habitat preference.

By combining aspects of behavioral ecology and landscape ecology, this study marks one of very few that show how animals use corridors to disperse across fragmented landscapes, and advance the field of corridor design by asking new questions about how we identify and validate landscape corridors.

Resources

Gillies, C.S. and C.C. St. Clair.  2008.  Riparian corridors enhance movement of a forest specialist bird in fragmented tropical forest. Proc Natl Acad Sciences USA 105:19774–19779.

LaPoint, S., P. Gallery, M. Wikelski, and R. Kays. 2013. Animal behavior, cost-based corridor models, and real corridors. Landscape Ecology doi: 10.1007/s10980-013-9910-0.

2016-10-14T10:11:06+00:00 July 31st, 2013|

About the Author:

Johnny Wilson
Johnny Wilson is a PhD student at North Carolina State University, focusing on conservation planning in a changing world. Originally from South Africa, he received his MSc at the University of Pretoria. He constantly struggles to find enough time for birdwatching.