Using habitat suitability models in an industrial setting: the case for internesting flatback turtles

Paul A Whittock,Kellie L Pendoley,Mark Hamann

doi:10.1002/ecs2.1551

Abstract

AbstractTo predict and manage ecological impacts of anthropogenic activities effectively, an understanding of at‐risk species spatial ecology is first required. This is particularly difficult in the marine environment due to limited offshore access and wide‐ranging movements of some species. Flatback turtles are a protected species potentially at risk from hazards associated with the resource sector in Australia, yet their at‐sea spatial ecology is not well understood. We use habitat suitability modeling to identify environmental variables that influence flatback turtle internesting movement; identify areas of suitable internesting habitat; and determine overlap of identified internesting habitat with resource sector hazards. Internesting movements of 47 female flatback turtles, from five rookeries in the North West Shelf region of Western Australia, were recorded using platform terminal transmitters between 2006 and 2010. Environmental variables including sea surface temperature (SST), bathymetry, magnetic anomalies, distance from coastline, slope, and ruggedness index were combined with the tracking data from each rookery in an ecological niche model. We used the positions of resource sector vessels to represent areas of potential impact from resource sector hazards and identified overlap with suitable internesting habitat areas as a representative of the likelihood of impact. The primary environmental variables that influenced flatback internesting movement were bathymetry, distance from coastline, and SST. Suitable areas of internesting habitat were located in close proximity to many known flatback turtle rookeries across the region. Areas of suitable internesting habitat overlapped resource sector hazards in close proximity to four of the five rookeries and at other known flatback turtle rookeries. The cumulative overlap across the overall study area indicates a high potential for interaction with resource sector hazards, demonstrating the need for regional protection measures in these areas. This study provides a capability for regulators and developers to determine the potential offshore presence of internesting flatback turtles within the region, allowing for protection measures to be targeted appropriately as industrial development continues.

Highlights

Human population growth has increased demand for natural resources (UNEP 2012), resulting in expanding resource extraction across the globe and an increased pressure on natural environments (Bellamy et al 2013)
All tracked flatback turtles remained within the boundaries of the North West Shelf (NWS) study area
Internesting locations from rookeries located on the mainland (Mundabullangana and Port Hedland) recorded lower mean ruggedness index values than those rookeries located on offshore islands (Ashburton, Barrow, and Thevenard)

Summary

Introduction

Human population growth has increased demand for natural resources (UNEP 2012), resulting in expanding resource extraction across the globe and an increased pressure on natural environments (Bellamy et al 2013). The uncertainty largely stems from a poor understanding of the spatial ecology including their ecosystem role and habitat preferences (Franklin 1995, Bellamy et al 2013). One technique is the generation of habitat suitability models to predict species distribution based on species preferences for different habitats across a combination of environmental variables (Guisan and Zimmermann 2000). Species distribution data, required for the model, can be simple presence or presence–absence data based on random or non-random field sampling (Guisan and Thuiller 2005). Models that rely on presence data are more commonly used when determining habitat suitability for wide-ranging species (Phillips et al 2006)

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Conclusion