It would be much easier to assess the effectiveness of different reintroduction methods, and so improve the success of reintroductions, if there was greater standardization in documentation of the methods and outcomes. We suggest a series of standards for documenting and monitoring the methods and outcomes associated with reintroduction projects for birds. Key suggestions are: documenting the planned release before it occurs, specifying the information required on each release, postrelease monitoring occurring at standard intervals of 1 and 5 years (and 10 for long-lived species), carrying out a population estimate unless impractical, distinguishing restocked and existing individuals when supplementing populations, and documenting the results. We suggest these principles would apply, largely unchanged, to other vertebrate classes. Similar methods could be adopted for invertebrates and plants with appropriate modification. We suggest that organizations publically state whether they will adopt these approaches when undertaking reintroductions. Similar standardization would be beneficial for a wide range of topics in environmental monitoring, ecological studies, and practical conservation.
Species databases are essential for the scientific management of species and specimens in captive wildlife populations. Population managers in North America base their decisions on information in two databases: the International Species Information System (ISIS) and American Zoo and Aquarium Association (AZA) approved regional studbooks. Genetic and demographic management of species relies on studbooks, whereas regional collection planning and management by Taxon Advisory Groups (TAGS) may use a combination of studbooks, direct surveys, and data from ISIS. Use of ISIS data as the primary basis for population management and collection planning is increasing, yet there has been no assessment of how ISIS data differ from studbooks. Thus these databases were compared to determine if they are interchangeable for the purposes of regional collection planning or species management. Population sizes of living individuals in 68 SSP" taxa were compared to assess the magnitude of differences between the databases. Differences in population size were considerable and highly variable; ISIS on average underestimated the number of living animals in SSPO taxa populations. Ten studbooks were also analyzed in detail to identify specific types of discrepancies between the two databases. On average, 19.2 k 2.2% of the information in the ISIS database differed from that in the studbook. Most discrepancies derived from data that were either missing from, or incorrect in, the ISIS database. The most common discrepancies involve parents who were either unidentified or misidentified in the ISIS database (Z = 37.5 k 5.7% of all records). No single type of discrepancy, however, was prevalent across all 10 species; the overall rate of discrepancies per species was attributable to a combination of discrepancies peculiar to each species. Protocols concerning data entry standards, data collection, and the scope of data collected are likely causes of most discrepancies. In its present form, the ISIS database is not appropriate for single species management; if used cautiously, it can be of assistance in the development of regional collection plans. Development of an ISIS database that is suitable for population management will require an increased commitment to data quality by records keepers, zoological institutions, and ISIS. 0 1995 Wiley-Liss, Inc Key words: regional studbooks, record keeping, zoo databases, ARKS, SPARKS, SSPOReceived for publication October 3, 1994; revision accepted June 1, 1995. Address reprint requests to Joanne M. Earnhardt, Lincoln Park Zoological Gardens, 2200 N. Cannon Drive, Chicago, IL 60614-3895.Q 1995 Wiley-Liss, Inc. INTRODUCTIONThe American Zoo and Aquarium Association (AZA) supports programs to monitor and manage breeding populations of captive wildlife in North America [Wiese and Hutchins, 19941. These cooperative programs make specific recommendations on aspects of husbandry and management that are based largely on quantitative analyses of demographic and pedigree information collected from participating ...
Abstract. We investigate how coexistence between competitors may be influenced by habitat selection when habitats represent either sources or sinks, and given that dispersal is free to evolve. Evolutionary stable dispersal between source and sink habitats can occur if local fitnesses vary temporally, either due to intrinsic factors (e.g., chaotic dynamics) or extrinsic factors (e.g., environmental stochasticity). The model assumes locally linear LotkaVolterra competition between two species. Given sufficiently low density-independent mortality in the sink, dispersal between habitats is an evolutionary stable strategy (ESS). Given a trade-off between competitive ability in the source and mortality in the sink, a sink habitat can promote species coexistence in the source habitat if the inferior competitor species experiences lower mortality in the sink. This highlights how sink habitats may provide mechanisms of coexistence in heterogeneous landscapes. In a second scenario, the competitors have distinct habitat preferences, resulting in the ''Ghost of Competition Past'' (i.e., complete habitat partitioning) with stable population dynamics. With unstable population dynamics, dispersal between habitats becomes the ESS, and the Ghost vanishes leading either to coexistence of the competitors in both habitats or global exclusion of one species. Our results highlight the importance of jointly considering the effects of spatial heterogeneity and temporal variability when analyzing the coexistence of competing, mobile organisms.
Headstarting is a conservation technique for improving survival of species with high juvenile mortality by accelerating growth rate and increasing body size of captive-born young. With reptiles, headstarts are often kept active year-round to achieve body size goals and increase survival, omitting overwintering (brumation). As brumation is part of the life cycle of reptiles, there may be tradeoffs related to temperature response post-release when reptiles are kept active. Upon release into habitats, reptiles are either soft released, where acclimation is provided with in situ enclosures, or hard released without acclimation, directly into habitat. Soft releases have resulted in greater survival and site fidelity than hard releases, but evaluations with snakes are rare. We used a comparative approach to examine effects of brumation versus year-round activity on prerelease growth and survival of smooth green snake Opheodrys vernalis headstarts. We estimated short-term post-release daily survival rates of headstarts and compared movements of hard and soft released snakes. Despite decreases in body mass during brumation, prerelease body size, growth rate and survival did not differ among brumation treatments. Brumated headstarts exhibited rapid compensatory growth, attaining the size of active headstarts within 2 months of brumation. We observed qualitative evidence of reproductive potential in brumated snakes with the production of spermatozoa and unfertilized eggs, which was absent in active headstarts. The short-term survival rate of all headstarts during post-release tracking was 0.83 (±0.01), but we lacked power to examine differences in survival among release treatments. Daily movements did not differ among release treatments. Soft releases had slightly greater recaptures, facilitating monitoring. Although brumation comparisons produced equivalent prerelease growth and survival, as a precautionary measure for post-release survival, we recommend incorporating brumation into headstarting efforts. While further study with other reptiles is warranted, we recommend a comparative framework in planning headstarting efforts with additional species.
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