Identifying Potential Connectivity for an Urban Population of Rattlesnakes (Sistrurus catenatus) in a Canadian Park System

Jonathan D Choquette,Matthew R Macpherson,Robert C Corry

doi:10.3390/land9090313

Abstract

In the face of ongoing habitat loss and fragmentation, maintaining an adequate level of landscape connectivity is needed to both encourage dispersal between habitat patches and to reduce the extinction risk of fragmented wildlife populations. In a developing region of southwestern Ontario, Canada, a declining population of Eastern Massasauga rattlesnakes (Sistrurus catenatus) persists in fragmented remnants of tallgrass prairie in an urban park system. The goal of this study was to identify potential connectivity pathways between habitat patches for this species by using a GIS least-cost permeability swath model, and to evaluate the outputs with snake road mortality data. Results identified seven pathways between five core habitat blocks, a subset of which were validated with aerial imagery and mortality data. Four high-ranking pathways intersected roads through or near road mortality hotspots. This research will guide conservation interventions aimed at recovering endangered reptiles in a globally rare ecosystem, and will inform the use of permeability swaths for the identification of locations most suitable for connectivity interventions in dynamic, urbanizing landscapes.

Highlights

In human-dominated landscapes, urban natural heritage systems support relatively high levels of biodiversity and may sustain regionally, provincially or nationally significant species
Species-specific GIS-based modeling tools have been widely used for large vertebrates at the broad scale to identify important areas for planning and design interventions aimed at enhancing landscape connectivity [6,7,8,9]
Seven high-ranking potential connectivity pathways (PCP1 through PCP7) for Massasaugas were identified between population blocks (Figure 5)

Summary

Introduction

In human-dominated landscapes, urban natural heritage systems support relatively high levels of biodiversity and may sustain regionally, provincially or nationally significant species These systems, are dynamic and highly susceptible to local extinctions due to isolation by roads and development, disturbance from recreational activities and adjacent land uses, and surrounding habitat loss [1,2,3]. Species-specific GIS-based modeling tools have been widely used for large vertebrates at the broad scale to identify important areas for planning and design interventions aimed at enhancing landscape connectivity [6,7,8,9] These techniques do not appear to be applied as often in urbanizing landscapes or for animals with smaller home ranges such as reptiles, despite their potential to act as an effective tool to help prioritize locations for connectivity design and planning between protected areas

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