Assessing landscape constraints on species abundance: does the neighborhood limit species response to local habitat conservation programs?

Paul Adam,Christopher F Jorgensen,Jeffery J Lusk,Joseph J Fontaine,Andrew A Bishop,Larkin A Powell

doi:10.1371/journal.pone.0099339

Paul Adam, Christopher F Jorgensen + Show 4 more

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https://doi.org/10.1371/journal.pone.0099339

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Abstract

Landscapes in agricultural systems continue to undergo significant change, and the loss of biodiversity is an ever-increasing threat. Although habitat restoration is beneficial, management actions do not always result in the desired outcome. Managers must understand why management actions fail; yet, past studies have focused on assessing habitat attributes at a single spatial scale, and often fail to consider the importance of ecological mechanisms that act across spatial scales. We located survey sites across southern Nebraska, USA and conducted point counts to estimate Ring-necked Pheasant abundance, an economically important species to the region, while simultaneously quantifying landscape effects using a geographic information system. To identify suitable areas for allocating limited management resources, we assessed land cover relationships to our counts using a Bayesian binomial-Poisson hierarchical model to construct predictive Species Distribution Models of relative abundance. Our results indicated that landscape scale land cover variables severely constrained or, alternatively, facilitated the positive effects of local land management for Ring-necked Pheasants.

Highlights

Habitat management and restoration are fundamental components of conservation science [1], [2], [3], [4], [5] and are routinely identified as the primary means to improve population viability for species of social-economic [6], [4], [7], [8] or conservation concern [9], [10], [11]
Of the seven topographic and land cover variables we investigated, the proportion of Conservation Reserve Program (CRP) and grass best explained the variability in pheasant abundance at the management scale (Figure 4), with pheasant populations responding positively to each
For Ring-necked Pheasant, did we find that populations were responding to unique ecological conditions at different spatial scales, we clearly demonstrate the capability of large scale conditions to both facilitate and constrain local habitat benefits

Summary

Introduction

Habitat management and restoration are fundamental components of conservation science [1], [2], [3], [4], [5] and are routinely identified as the primary means to improve population viability for species of social-economic [6], [4], [7], [8] or conservation concern [9], [10], [11]. Despite our ability to routinely produce ‘suitable’ vegetative conditions, habitat management actions too often fail to meet the population expectations of managers e.g., [12], [13], [14], [15]. Recognizing that individuals select among available habitats based on a set of environmental cues is fundamental to habitat selection theory, and is useful in predicting habitat suitability [16], [17]. Associating land cover variables with species occurrence or abundance on a spatial scale relevant to the species, potentially through the use of an SDM, may provide insight into how individuals make habitat decisions, and what constitutes suitable habitat [21]

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