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TNC's Need for Ecoregional Planning Tools
Approach
Applications of Sites revised
October 11, 2001
Related Online Resources revised
October 11, 2001
Background
The Nature Conservancy (TNC) recently
initiated a new program of ecoregion-based conservation. The goal of this
effort is to assemble regional portfolios of conservation lands that collectively
represent viable examples of all native species and plant communities.
This program aims to increase the efficiency and effectiveness of TNC's
conservation activities through a systematic approach to regional portfolio
assembly coupled to local, on-the-ground implementation.
TNC's Need for Ecoregional Planning
Tools
The initial steps in ecoregional conservation planning involve identifying
an explicit conservation goal, selecting a set of target elements (i.e.,
species and communities), identifying levels of representation for each
target, and then identifying a potential portfolio of sites. In many ecoregions
where TNC works, there are hundreds of target elements to consider, as
well as a variable number of potential conservation sites, each of which
may differ in quality or suitability. To prioritize among potential conservation
sites as the portfolio is assembled, often a hierarchical set of decision
rules is applied. For each ecoregion where TNC works, the general process
of portfolio assembly wll be similar, but the specific combination of goals,
targets, sites, and decision rules likely will be unique.
Given the large number of species, communities and potential sites in
many ecoregions, without the aid of computer automation, it is virtually
impossible for conservation planners to evaluate all possible alternative
portfolios that potentially could meet a stated conservation goal. Computer
automation also is needed because the portfolio assembly process is iterative,
and once an initial portfolio is identified, there is an ongoing need to
revise that portfolio. For example, the potential portfolio might change
as a result of revisions to TNC's conservation goal for that ecoregion,
or as a result of new data (e.g., for sites or elements not previously
surveyed; or when the status of an element or site changes because of ownership
changes). Without the aid of computer-based decision rules, it is difficult
to develop an iterative portfolio assembly process that is repeatable,
and the process of reviewing alternative site combinations can be labor
intensive as well as unnecessarily slow. In the last decade, a variety
of computer-based algorithms and analytical approaches for reserve siting
has been developed, however, at the time this project was initiated, these
remained primarily research tools. Based on discussions with various TNC
staff involved with ecoregional planning efforts, in their current form,
none of the existing approaches was well-suited to TNC's planning needs.
From TNC's perspective, the major limitations of current tools fell into
three general categories: those that require high end computing power,
specialized software, and/or a high level of GIS technical expertise (e.g.,
BMAS,
Church et. al. 1996); those with insufficient documentation and/or
inadequate testing of computer code; or those with overly simplistic decision
rules (e.g., "greedy" or rarity-based heuristics).
Approach
The following research and development effort for TNC was conducted:
-
Develop Sites 1.0, with an easy-to-use graphical interface in ArcView to
select and display alternative portfolio solutions.
-
Adapt the SPEXAN software for selecting reserve sites (written by Ian Ball
and Hugh Possingham of the University of Adelaide in Australia) to accommodate
TNC's portfolio design methodology. The version used in Sites, called
the Site Selection Module, like SPEXAN, explicitly incorporates spatial
design criteria into the site selection process.
-
Test and apply the planning approach in a structured decision process involving
local TNC staff to develop hypothetical conservation portfolios in two
different ecoregions (Idaho Batholith and the Northern Sierra Nevada).
-
Produce a web-based tutorial, including a worked example using TNC data
and ecoregions; and conduct a training workshop for TNC staff interested
in learning and applying the regional conservation planning tools to other
TNC regions.
Applications of Sites 1.0
The following planning studies that have used Sites 1.0 have been presented
at conferences or published in the peer-reviewed literature (as of October
11, 2001):
-
Prioritizing
Sites for Endangered Species Conservation along the Santa Clara River
(large pdf file)
-
TNC
Conservation portfolio for the Middle Rocky Mountains - Blue Mountains
Ecoregion (abstract of poster presented by TNC planning team at the
2000 Society for Conservation Biology conference)
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Conducting
large-scale conservation evaluation and conservation area selection using
a knowledge-based system (paper presented at GIS/EM4 in 2000 by Patrick
Bourgeron of University of Colorado)
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Prioritizing
Conservation Efforts in the Sierra Nevada Ecoregion. Paper presented
by Bo Wilmer at the 2001 ESRI User
Conference.
-
Ecoregions and species assemblages: testing indicators for identifying
areas of conservation concern. Paper presented by Josh
Lawler at the 16th Annual Symposium of the U.S. Chapter of International
Association of Landscape Ecology, Tempe, Arizona, April 2001.
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Leslie, Heather, Mary Ruckelshaus,
Ian R. Ball, Sandy Andelman, and Hugh P. Possingham. Using siting algorithms
in the design of marine reserve networks. In press. Ecological Applications.
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Beck, M. W. and M. Odaya. 2001. Ecoregional planning in marine
environments: Identifying priority sites for conservation in the northern
Gulf of Mexico. Aquatic Conservation 11: 235-242.
Related Online Resources
These web sites provide further background on the simulated annealing approach
to reserve selection (as of October 11, 2001):
-
MARXAN--the successor
of SPEXAN--home page with descriptions, history, and more publications.
Hugh Possingham.
-
Mathematical
methods for identifying representative reserve networks (pdf file of
a book chapter by Hugh Possingham et al. 2000 that describes simulated
annealing process and spatial design features used in Sites).
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