Setting Priorities for Land Conservation (1993) / Chapter Skim
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Appendix D: The Nature Conservancy: Acquisition Priorities and Preserve Selection and Design
Appendix D: The Nature Conservancy: Acquisition Priorities and Preserve Selection and Design
Pages 247-260
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From page 247... ...
stated "it has proven markedly successful in securing natural areas using a revolving fund and arranging for their protection, either by transferring responsibility to a stable institution in state or federal government or by managing it themselves." Goals TNC states Hat its primary objective is to conserve biological and ecological diversity. To this end, TNC lists, classifies, characterizes, and inventories "the enormous diversity and complexity of our biota, ecosystems, and landscapes." The Nations Heritage Program Operation Manual (NHPOM)
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. Priorities Because it is impossible to inventory all biological diversity, heritage programs tend to focus on He rarest, most endangered, and most vuInerable species (including intraspecific tax e)
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heritage programs have standard data collections and information storage. The manual is a technical one; specific information to collect usually is left to the discretion of He staff in each state and is, in part, dependent on He information base already accrued in each state.
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Common units of comparison: The heritage program developed the concept of elements of diversity that are defined as species, community types, or other special features. The standard nomencIamre is "element, element occurrence, site (land unit of preserve design)
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Standardization: The heritage program "exhibits an unprecedentedly high degree of standardization throughout. Absolute uniformity is maintained, 'which is crucial for data exchange, efficient research, system evolution, and data retrieval for users." Central support, data bases, and networking: The science division trains new staff, develops new procedures, compiles suggestions from field offices, raises funds, maintains operating manuals, monitors individual programs, facilitates interaction among programs, encourages cooperation with over agencies and institutions, and maintains a central data base.
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This information is important to heritage programs because: I) a large proportion of He biological diversity of a state often occurs on managed land, so conservation efforts will not be wasted on an element already protected to some degree, 2)
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This manual deals primarily with the administrative procedures of designing reserves and Aloes not deal at length with the scientific aspects of preserve design." The protection activities rely on three information sources provided by heritage programs: I) The Natural Diversity Scorecard lists elements in order of their
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3) The Pr7onty Site Lists is produced by analyzing the site tracking record and listing sites in order of significance that will contribute the most to natural diversity preservation.
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Some central questions are what the minimum viable size a reserve must be to retain the greater part of its biota over the long term and what the minimum viable population a species must have to avoid a significant loss of alleles and eventual extinction on a site. Sites are categorized as megasiees (more than 64,000 acres)
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From page 256... ...
The PS&D uses the tea "minimum viable size of preserves," although it is generally understood that minimal viable preserve size varies with the EOs targeted for preservation. A hectare may be sufficient to preserve a self-fertilizing, long-lived plant, but a half million hectares in a fragmented landscape may be insufficient to preserve a population of a large vertebrate predator.
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From page 257... ...
Tracts available for preserves tend to be much smaller than desirable, but accumulating many unconnected tracts containing rare EOs might reduce the probability of extinction; if local extinctions occur, reintroductions are possible. The concept of corridors is not well defined, according to a member of TNC's board of directors (Sto~zenberg, 1991)
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described three studies that demonstrate the efficacy of corridors for maintaining populations: Harper in Brazil found that corridors were essential for maintaining antbirds in patches of jungle, Bennett In Australia discovered that corridors provide both transportation and a conduit for gene exchange, and Merriam in Canada found that woodIots connected by wooded fencerows demonstrated a continual process of extinction and recolonization by small mammals and birds. In practice, some TNC conservation efforts have integrally incorporated corridors.
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From page 259... ...
Sitespecific data from field surveys is one key to TNC success. It is important, Dough, Mat data gatherers be instructed in the empirical and theoretical literature that may cast light on how to monitor and measure the ecological health of a particular site.
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