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Society for Conservation Biology: 2002 Annual Meeting

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Society for Conservation Biology: 2002 Annual Meeting


Society for Conservation Biology 16th Annual Meeting July 14-July 19 2002
co-hosted by DICE and the British Ecological Society


Abstracts for Recovery of Endangered Species
Session One

Wednesday 17th July, 10.15 - 12.15, Grimond Lecture Theatre 1

Chair: Richard Griffiths




(BLOCK CAPITALS indicate the presenting author)

10.15 - 10.30
FLESSA, KARL W., Carlos E. Cintra-Buenrostro, Sarah K. Noggle and David L. Dettman. Department of Geosciences, University of Arizona, Tucson, AZ 85721, USA, <kflessa@geo.arizona.edu>.

CONSERVATION PALEOBIOLOGY OF AN ENDANGERED ESTUARINE MOLLUSC: PLAYING BACK THE SKELETAL RECORD

How can one study the biology of a now-endangered species if individuals are so rare that observation is difficult and experimentation is unethical? Analyses of preserved hard parts can provide information on the habitat requirements and ecological role of the species when it was still abundant. Before the construction of upstream dams and diversions in the 1930’s, the bivalve Mulinia coloradoensis was the most abundant mollusk in the estuary of the Colorado River. Today, the species is endangered by the increased salinity caused by the lack of river flow. We examined the sclerochronology and stable oxygen isotope variation in pre-dam specimens to estimate the species’ salinity preferences. We counted drillholes and shell repair to estimate the species’ importance in the pre-dam food web. Oxygen isotopes indicate strong fluctuations in salinity caused by seasonal variation in river discharge. Restoration of this species would likely require ~10% of the river’s annual flow, delivered between May and July. Approximately 60% of the shells had either a drillhole made by a predatory gastropod or a scar from an unsuccessful attack by a crab. The post-dam decline in the population of Mulinia coloradoensis probably caused a decline in the population size of its predators.

10.30 - 10.45
ENGLUND, RONALD A., Dan A. Polhemus, and Steven D. Jordan. Hawaii Biological Survey, Bishop Museum, 1525 Bernice St., Honolulu, Hawaii 96817, USA, <englund@bishopmuseum.org> (RAE), Dept. of Entomology, MRC 105, Smithsonian Institution, Washington, DC 20560, USA (DAP), Dept. of Ecology and Evolutionary Biology, U-43, University of Connecticut, Storrs, CT 06269, USA (SDJ).

CONSERVATION OF TROPICAL INSULAR PACIFIC AQUATIC INSECTS: TWO CASE STUDIES FROM HAWAII

Hawaii, the most isolated archipelago in the world, has received considerable attention because of extinctions among honeycreeper birds and endemic plant species. Although just as spectacular as the honeycreeper or silversword radiations, aquatic insects have received comparatively little attention. While conservation efforts in Hawaiian freshwater habitats are directed at large, edible vertebrates such as native freshwater fishes, little work has focused on insects that comprise the principal component of biodiversity in these freshwater systems. Many endemic aquatic insect radiations in Hawaii are currently threatened by alien species and habitat disturbances. Two conservation case studies are presented, the Hawaiian orangeblack damselfly (Megalagrion xanthomelas), and the giant midge genus Telmatogeton. Disparate knowledge of conservation strategies, life—histories, and distributional patterns between these taxa exemplifies the contrast between the large and beautiful damselflies compared to the more cryptic aquatic Diptera. On Oahu, the orangeblack damselfly has been reduced to little more than 100 m of stream, and species in the genus Telmatogeton are now found on only four of the 57 perennial streams. While initial successes have been made in preserving the Oahu M. xanthomelas population, Telmatogeton species appear to be declining and are found only in remote and pristine aquatic habitats.



10.45 - 11.00
MCGRATH, CLAIRE C., and William M. Lewis, Jr. Center for Limnology, Cooperative Institute for Research in Environmental Science, University of Colorado, Boulder, Colorado, USA, <claire.mcgrath@colorado.edu>.

INVASIVE BROOK TROUT JEOPARDIZE RESTORATION OF NATIVE GREENBACK CUTTHROAT TROUT IN THE ROCKY MOUNTAINS, USA

The greenback cutthroat trout, Oncorhynchus clarki stomias, is listed as a threatened subspecies under the U.S. Endangered Species Act. Restoration efforts during the past 30 years have focused on stocking suitable habitats with hatchery-reared greenback cutthroat trout. However, non-native brook trout, Salvelinus fontinalis, continue to displace native cutthroat trout in many areas. In an ongoing study at ten stream sites, we describe the population dynamics and feeding ecology of the two species. To alleviate effects of brook trout on greenback cutthroat trout, we used a two-pass electrofishing technique to remove brook trout from three stream reaches. However, low capture efficiencies and rapid recolonisation of brook trout from adjacent reaches prevented the effective removal of brook trout. Analysis of population, body condition, stomach content, and stable isotope data indicates that brook trout decrease the recruitment and/or survival of young greenback cutthroat trout, and that interspecific competition for food among adult trout is not the major mechanism for displacement of greenback cutthroat trout. Currently, we are investigating competition for food among young-of-year trout and predation upon greenback fry as possible mechanisms for displacement of greenback cutthroat trout by brook trout.



11.00 - 11.15
BATIE, ROBERT. Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 48824-1222, USA, <rbatie@msu.edu>.

RECOVERY EFFORTS FOR THE FEDERALLY ENDANGERED VIRGINIA FRINGED MOUNTAIN SNAIL, POLYGYRISCUS VIRGINIANUS

Polygyriscus virginianus, found in southwest Virginia, USA, is one of the most rare land snail species in North America. Since its discovery in 1937, only 28 living specimens have been found, 24 preserved prior to being listed as Federally Endangered in 1978. It has been sighted alive on only 4 occasions. This study extends the range of shells to a 10 km length along the talus slopes of the New River. The range of living snails, most (27 of 28) being found in a single talus pile measuring about 9 m2, is extended to 70 m. About 3.5 mm in shell width, Polygyriscus is restricted to loose, angular fragments of Elbrook formation limestone (Cambrian). A dense canopy of hardwoods and a thick understory of honeysuckle vines, which keep the rock fragments continually moist, heavily shade the type locality. Management and recovery challenges include closely monitoring the habitat to prevent further habitat disruption through canopy removal, fire, roadside spraying of herbicides, or collecting by non-authorized, amateur collectors.



11.15 - 11.30
HOEKSTRA, JONATHAN M., Tamara Harms, Jerald B. Johnson, Jessica Piasecke and Mary Ruckelshaus. Northwest Fisheries Science Center, National Marine Fisheries Service, Seattle, WA, USA, <Jonathan.Hoekstra@noaa.gov>.

THE RELATIVE IMPACT OF HABITAT, HYDRO-DAMS, HARVEST AND HATCHERIES ON PACIFIC SALMON TRENDS

The four "H’s" — habitat quality, hydroelectric dams, harvest and hatchery production — are widely viewed as the dominant causes of endangerment of salmon in the Pacific Northwest, USA. However, the relative importance of the four "H’s" has not yet been systematically assessed across a broad regional scale. Furthermore, their combinatorial effects are only beginning to be tested and quantified. We undertook a region-wide multivariate analysis designed to estimate the effects of all four "H’s" on salmon population growth rates (lambda). We compiled geographically related databases of population trend estimates, hydrologic dam attributes, land-use/land-cover, harvest rates, and hatchery production through Washington, Idaho, Oregon and California. We then fit candidate structural equation models to our data to identify a suite of plausible models representing direct and indirect effects of the four "H’s". Direct effects quantified the relative impact of each "H" on lambda, while indirect effects quantified the strength of interactions between the "H’s". This "All-H" analysis predicts the likely effectiveness of recovery actions aimed at particular "H’s", and suggests potential synergistic or antagonistic effects of actions targeting other "H’s". Such insights will aid regional prioritisation of recovery actions and thus promote more effective recovery planning for threatened and endangered salmon.



11.30 - 11.45
SOUTER, NICHOLAS J., C. Michael Bull and Mark N. Hutchinson. School of Biological Sciences, Flinders University of South Australia, G.P.O. Box 2100, Adelaide, South Australia 5001, Australia, <nsouter@adam.com.au> (NJS, CBM), South Australian Museum, PO Box 234, Adelaide, South Australia 5001, Australia (MNH).

IS THE ENDANGERED PYGMY BLUTONGUE LIZARD A FLAGSHIP FOR GRASSLAND CONSERVATION OR ITS MARIE CELESTE?

The endangered Pygmy bluetongue Lizard, Tiliqua adelaidensis, inhabits threatened remnant native grasslands, in South Australia. We examined the relationship between lizard abundance and grassland community structure along transects across the edges of lizard populations. Our hypothesis was that lizards should be associated with specific native plant communities. Transect data from five sites, four with lizard populations of varying sizes and one without lizards, showed significant differences in vegetation community structure among sites, but not across lizard population boundaries within sites. The sites with the greatest lizard abundance had the lowest native plant diversity whilst the site with no lizards, a conservation park, had the highest native plant diversity. Floral diversity and species composition were thus poor predictors of lizard abundance. We started with an apparently reasonable assumption, that conservation of individual species and the communities they inhabit should be complementary. This example demonstrates that this assumption need not be true. In this case establishing a reserve with conditions suitable for the conservation of the Pygmy bluetongue would not conserve a significant tract of native vegetation, whilst the conservation park studied was proclaimed due to its high diversity of native plant species but does not support any lizards.



11.45 - 12.00
CLARK, J. ALAN and Erik Harvey. Department of Zoology, Box 351800, University of Washington, Seattle, WA 98195-1800, USA, <alanc@u.washington.edu> (JAC), Arizona State University, Department of Biology, Tempe, AZ 85287-1501, USA (EH).

SINGLE-SPECIES APPROACHES MAY SURPASS MULTI-SPECIES/ECOSYSTEM APPROACHES TO SPECIES RECOVERY

Governmental agencies are relying increasingly on multi-species or ecosystem, rather than single-species, approaches to biodiversity recovery. Supporters of multi-species/ecosystem approaches note potential efficiency gains in terms of agency time and resources. Critics express concern that multi-species/ecosystem recovery plans often lack essential species-specific information. To assess these claims, we evaluated recovery plans developed under the U.S. Endangered Species Act (ESA). Previous studies showed that species from multi-species/ecosystem plans were more likely to exhibit a declining status trend. We explored this difference by using an extensive pre-existing recovery plan database to analyse differences in basic plan attributes between single-species and multi-species/ecosystem recovery plans and found that multi-species/ecosystem plans reflect a poorer understanding of species biology and enumerate fewer recovery tasks. We also assessed species attributes within plan types and found that multi-species/ecosystem plans present less biological information, are less likely to suggest adaptive management, have fewer recovery tasks implemented, and are revised less frequently. Finally, we calculated a "threat congruence index" to evaluate the relative agreement in addressing threats within multi-species/ecosystem plans and found a startling lack of congruence in many plans. For the ESA, the presumed benefits of multi-species/ecosystem recovery efforts are not being realised.



12.00 - 12.15
GOOD, THOMAS P. and Phillip S. Levin. Northwest Fisheries Science Center, National Marine Fisheries Service, 2725 Montlake Boulevard East, Seattle, WA 98112, USA, <tom.good@noaa.gov>.

IS CONSERVATION SCIENCE FITTING THE BILL?: A DOLLARS AND SENSE ANALYSIS OF PACIFIC SALMONIDS

The crisis mode inherent in many conservation issues hinders traditional methods of scientific inquiry and the dissemination of information. In the U.S., almost half of the populations of wild Pacific salmon are at risk of extinction. Despite spending hundreds of millions of dollars on salmon research in the last decade, large gaps in our scientific knowledge remain, and scientific uncertainty is not well defined. We examined the use of ecological experiments in salmon research and the dissemination of information from publicly funded research through peer-reviewed journals. A survey of fisheries journals revealed that 2.6% of papers on Pacific salmon used field experiments--a figure much lower than some other conservation disciplines or basic ecology. Over a ten-year period, projects on conservation biology funded by the National Science Foundation (NSF) generated an average of 3.86 peer-reviewed publications per $100,000. Projects on salmon, with budgets ten times those of NSF funded projects, generated an average of 0.11 peer-reviewed publications per $100,000 over the same period. We argue that the use of an experimental, hypothesis-testing approach and more rigorous accountability by funding agencies is likely to improve our understanding of endangered salmonids and species of conservation concern in general.