Selecting
conservation reserves using species covering models: Adapting
the ARC/INFO GIS
Ross A. Gerrard, Richard L Church, David M. Stoms, and Frank W.
Davis
Conflicts
between human development of the landscape and conservation of
biodiversity will continue to grow. Given this reality, there
have been a number of attempts to model the optimal selection
of conservation reserve sites such that maximum biodiversity protection
can be attained within a limited budget for land acquisition.
Here we adapt the Location-Allocation module of ARC/INFO to solve
the problem of representing, or covering, as many species as possible
in a fixed number of selected reserve sites. Resident ARC/INFO
solution routines are applied to an innovative logical network
that converts the problem of optimal reserve selection into a
problem of optimal facility placement, which the Location-Allocation
module can recognize and solve. Use of this unique logical network
structure as input to ARC/INFO's internal solvers makes possible,
compared to previous methods, a much tighter integration of spatial
optimization tools with mapping and database tools, all of which
are internal to the GIS and accessed via a menu-driven interface.
The main advantage is that users of public domain data (such as
the U.S. Gap Analysis data) can conduct their own explorations
of possible reserve systems without having to acquire and master
optimization packages and reformat model output data for GIS display
and post-analysis of solutions. Our sample application uses species
data from southwestern California. We also present a second major
form of species covering model grounded in the same logical network.
This enhanced model accommodates weighting of species by their
conservation importance, thus allowing reserve systems to be designed
around the portection of the most threatened or vulnerable biota.
Demo
of the species covering application