Optimal Corridor Design for Grizzly Bear in the U.S. Northern Rockies

In an attempt to address the negative ecological impacts of habitat fragmentation, wildlife corridors have been proposed as a way to connect areas of biological significance. In this paper, a model to maximize the amount of suitable wildlife habitat in a fully connected parcel network linking core habitat areas subject to a budget constraint is introduced. The standard economic framework of maximizing habitat benefits subject to a budget constraint that we employ in this paper is a divergence from other recently proposed models that focus only on minimizing the cost of a single parcel-wide corridor. While the budget constrained optimization model that we introduce is intuitively appealing, it presents substantial computational challenges above determining the cost-minimizing corridor. The optimization model is applied to the design of a wildlife corridor for grizzly bears in the U.S. Northern Rockies and is shown to drastically increase the aggregate habitat suitability of the corridor over parcel selection based on cost minimization alone. The relative tradeoffs between corridor cost and habitat suitability are illustrated through the construction of an efficiency frontier and, for cases where optimization is computationally impractical, a heuristic is suggested that closely approximates the optimally selected corridor.