291
17
Mathematical Methods for Identifying
Representative Reserve Networks
Hugh Possingham, Ian Ball, and Sandy Andelman
Introduction
Many countries have committed to conserving significant amounts of their native
biodiversity (McNeely et al. 1990). Biodiversity includes the diversity of ecosystems and the diversity between and within species. Reserve systems dedicated
to nature conservation are the cornerstone of most national, regional, and state
conservation strategies (Soul´ e 1991).
In this chapter, we explore the question of which parcels of land, henceforth
termed sites, should be selected for reservation. Implicit in our analysis is a limit
on the total size of the reserve system. From the perspective of nature conservation alone, one would attempt to have the largest reserve system possible; however, in reality, the extent of any reserve system will be limited by social and
economic constraints. Thus, building a reserve network that will conserve biodiversity effectively is not a process of accumulating as much land as possible but,
rather, necessitates doing so as efficiently as possible within a constrained area.
We focus on a particular class of reserve design problem in which the goal is to
achieve some minimum representation of biodiversity features for the smallest
possible cost. In these problems, the objective is to minimize costs, and biodiversity enters as a constraint. For example, governments have agreed to conserve
15% of the pre-European extent of Australia’s regional forest types. This sets a
constraint, creating an imperative to provide algorithms to minimize opportunity
costs to the timber industry or maintenance costs of reserve management, while
still satisfying the representation constraint. It is worth noting that there is no
guarantee that such a reserve system is adequate—an issue that can only be
assessed by using explicit population models (see Chapters 7–13, this volume).
To provide some perspective, we briefly review how reserves have been selected
in the past before proceeding with specific examples.
17
Mathematical Methods for Identifying
Representative Reserve Networks
Hugh Possingham, Ian Ball, and Sandy Andelman
Introduction
Many countries have committed to conserving significant amounts of their native
biodiversity (McNeely et al. 1990). Biodiversity includes the diversity of ecosystems and the diversity between and within species. Reserve systems dedicated
to nature conservation are the cornerstone of most national, regional, and state
conservation strategies (Soul´ e 1991).
In this chapter, we explore the question of which parcels of land, henceforth
termed sites, should be selected for reservation. Implicit in our analysis is a limit
on the total size of the reserve system. From the perspective of nature conservation alone, one would attempt to have the largest reserve system possible; however, in reality, the extent of any reserve system will be limited by social and
economic constraints. Thus, building a reserve network that will conserve biodiversity effectively is not a process of accumulating as much land as possible but,
rather, necessitates doing so as efficiently as possible within a constrained area.
We focus on a particular class of reserve design problem in which the goal is to
achieve some minimum representation of biodiversity features for the smallest
possible cost. In these problems, the objective is to minimize costs, and biodiversity enters as a constraint. For example, governments have agreed to conserve
15% of the pre-European extent of Australia’s regional forest types. This sets a
constraint, creating an imperative to provide algorithms to minimize opportunity
costs to the timber industry or maintenance costs of reserve management, while
still satisfying the representation constraint. It is worth noting that there is no
guarantee that such a reserve system is adequate—an issue that can only be
assessed by using explicit population models (see Chapters 7–13, this volume).
To provide some perspective, we briefly review how reserves have been selected
in the past before proceeding with specific examples.