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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 Conservation and Amphibians and Reptiles
Session Two

Wednesday 17th July, 15.30 - 17.30, Grimond Lecture Theatre 3

Chair: Nicola Mitchell




(BLOCK CAPITALS indicate the presenting author)


15.30 - 15.45
FAUTH, JOHN E. Department of Biology, College/University of Charleston, Charleston, South Carolina, USA, <fauthj@cofc.edu>.

RESTORING AMPHIBIAN DIVERSITY IN MANUFACTURED PONDS: HERPETOLOGISTS STRIKE BACK

Ecological theory predicts that ponds with intermediate hydroperiods will maintain the greatest diversity of amphibians, and of other species with complex life cycles. I tested this hypothesis by experimentally draining two types of permanent, manufactured ponds: wildlife ponds and borrow pits. The former were intentionally created as wildlife watering holes, while the latter are aquatic habitats created when construction crews remove fill for roads. The experiment had a 2 x 2 x 2 x 3 design, where treatments were the two pond types, which were drained either in summer alone, in winter alone, in both summer and winter, or never. Each of these eight treatments was replicated three times within a southeastern U.S. national forest. Twelve nearby natural, temporary ponds were sampled for amphibians at the same time, to assay natural patterns of variation in species richness and abundance. Pond-draining had tremendous affects on amphibian species richness, which varied significantly with pond type. Species richness in borrow pits doubled, and increased 50% in wildlife ponds. Summer draining increased species richness more than draining in winter. The results indicate pond-draining, which is another application of the intermediate disturbance hypothesis, can rapidly restore amphibian diversity in manufactured wetlands.


15.45 - 16.00
TRAEHOLT, CARL, Sirka L. L. Lundahl, Daimil Pedeko, Victor Pilang, Biseh Banggilon, Suati Dullah, Mohd. Rafie Bunggou and Mohd. Sulaiman. Maliau Basin Conservation Project, 9th Floor Wisma Innoprise, Kota Kinabalu, Sabah. <ctraeholt@pd.jaring.my>.

PRELIMINARY SURVEY OF AMPHIBIANS IN MALIAU BASIN CONSERVATION AREA, SABAH, MALAYSIA.

In conjunction with the Maliau Basin Conservation Area project, Sabah, Malaysia, collection of amphibians was carried out in many new areas of undisturbed forest inside MBCA as well as in the adjacent lowland consisting of secondary dipterocarp forest. We collected 91 specimens from 9 localities, representing 31 species. Since most of them have never been collected in MBCA before, they can be considered as new recordings. Two rare genetic variants of R. kuhli and R. palavanensis were collected. MBCA with its high variety of habitats can be considered an amphibian hotspot. In order to secure its future status as a conservation area, it is important that it receives significant support from both national and international conservation societies and institutions.



16.00 - 16.15
BOL, LESLIE and David M. Green. Redpath Museum, McGill University, 859 Sherbrooke St. West, Montréal, Québec, H3A 2K6, Canada <lbol@po-box.mcgill.ca>

BREEDING AND RECRUITMENT OF SIX AMPHIBIAN SPECIES WITHIN A UNESCO BIOSPHERE RESERVE

The minimum number of aquatic breeding sites required for an amphibian species to persist at the landscape level may differ according to reproductive strategies and life history. The breeding and recruitment success of six amphibian species was investigated at 25 aquatic sites within an 1100 ha UNESCO biosphere reserve. Breeding sites included a 36 ha lake and ponds ranging from 25 to 2000 m2. Sites were monitored on a weekly basis over a four-month period. Breeding occurred in the lake for Bufo americanus, at one pond for Hyla versicolor, at 10, 11 and 12 sites respectively for Ambystoma laterale, Pseudacris crucifer and Ambystoma maculatum and at 17 sites for Rana sylvatica. The number of sites with recruitment was low for all species; 1 site each for Bufo americanus and Hyla versicolor, 3 for Ambystoma laterale, Ambystoma maculatum, Rana sylvatica and 6 for Pseudacris crucifer. Recruitment failure was due primarily to pond desiccation and disease. For species that reproduce at many sites (eg. Rana sylvatica), the loss of a single breeding habitat may be less detrimental to the overall persistence of the population than for those species that restrict their breeding to fewer sites (eg. Hyla versicolor).



16.15 - 16.30
DIETERICH, MARTIN. Dieterich, Beinlich & Partner - Consulting, Planning and Research, Röntgenstrasse 17, Kirchheim, D-73230, Germany, <dieterim@fh-nuertingen.de>.

MANAGEMENT OF THE YELLOW-BELLIED TOAD (BOMBINA VARIEGATA)

The yellow-bellied toad, Bombina variegata, is an endangered species listted in the EU Flora-Fauna-Habitat directive. Throughout its range populations have declined within the recent past. This floodplain species is restricted for successful reproduction to early successional ponds and puddles. The life cycle and the reproductive strategies of the yellow bellied toad are closely adapted to stochastic disturbance (spatial and temporal risk-spreading). Reproductive success is strictly limited by predators. As floodplain habitat was lost throughout central Europe, the yellow-bellied toad succeeded to shift reproduction to man-made habitats. The success of different management tools for a yellow-bellied toad population associated with truck-tracks was assessed. Adequate monitoring of reproductive success requires the count of freshly metamorphosed juveniles. Egg counts or habitat use by adults is often misleading, as eggs and freshly hatched tadpoles are quickly consumed by newts (e.g. Triturus alpestris) or dragonfly larvae (e.g. Libellula depressa). Successful management of reproductive habitats requires continuous establishment of early successional puddles during the reproductive period. Tools tested to provide habitat for reproduction include directed generation of truck-track puddles, temporary exposure of silo-foils, ditch management during forestry operations, and the establishment of erosional ponds in desiccating streams.



16.30 - 16.45
KOLOZSVARY, MARY BETH, Aram J. K. Calhoun and Malcolm L. Hunter, Jr. University of Maine, 5755 Nutting Hall, Orono, ME 04469, USA, <MaryBeth.Kolozsvary@umit.maine.edu>.

IS CONSERVATION OF TEMPORARY WETLANDS IMPORTANT FOR WOOD FROGS AND SPOTTED SALAMANDERS?

Many amphibians rely on wetlands for reproduction and the differential distribution of breeding amphibians along a gradient of wetland permanence is striking, yet not absolute. In recent years, conservationists have become concerned about declines in populations of wood frogs, Rana sylvatica, and spotted salamanders, Ambystoma maculatum, throughout much of their range. These species are thought to rely on temporary wetlands (vernal pools) for greatest breeding success – despite a lack of documentation of their reliance on these habitats. Our objective was to determine what wetland characteristics, including hydroperiod, are most important for successful reproduction of these species. We documented reproductive effort for wood frogs and spotted salamanders by counting egg masses in 72 wetlands in Acadia National Park in 1999, 2000, and 2001. We also examined egg and larval survivorship (2000 and 2001) and obtained an index of reproductive success (2001) at a subset of these wetlands. Our results indicate that for wood frogs, hydroperiod affects both reproductive effort and success; however, for spotted salamanders, hydroperiod drives reproductive success, but not reproductive effort. These results will help direct conservation efforts by identifying characteristics of wetlands that indicate a high potential for providing suitable breeding habitats for each of these species.



16.45 - 17.00
PYKE, CHRISTOPHER R. Department of Geography, University of California, Santa Barbara, CA, 93106, USA, <pyke@geog.ucsb.edu> (CP).

VERNAL POOLS AND CLIMATE CHANGE: COMPETITIVE INTERACTIONS OR REPRODUCTIVE LIMITATION?

Ephemeral, depressional wetlands are found in ecosystems around the world, and they include savannah rain pools, playa lakes, and vernal pools. They often contain exceptional levels of biodiversity and many sustain floras rich in endemic species. These ecosystems are often in conflict with human development, and they have been disproportionately impacted by habitat loss and degradation. As a result, a significant number of obligate species are threatened with extinction. Although habitat loss is the proximal threat to these ecosystems, climatic forces may determine the long-term success or failure of conservation and restoration measures. This research focused on the implications of climatic change for vernal pool aquatic invertebrates, particularly fairy shrimp. A process-based vernal pool hydroregime model was used to simulate conditions for vernal pool landscapes in the Central Valley of California. A stochastic weather generator was used to downscale predicted climate changes and develop long-term meteorological time-series with daily resolution. Results suggest that vernal pool invertebrates in California may be more at risk from ecological interactions due to lengthening hydroperiods, than reduced reproductive opportunities associated with droughts and higher temperatures. The predicted changes in hydrologic regime may drive competitive interactions leading to extirpation, and possible extinction, of already threatened species.



17.00 - 17.15
CALHOUN, ARAM J. K. and Michael W. Klemens. University of Maine, 5722 Deering Hall, University of Maine, Orono, Maine 04469, USA, <Calhoun@maine.edu> (AJKC) and Wildlife Conservation Society/ Metropolitan Conservation Alliance, 68 Purchase St., 3rd Floor Rye, NY 10580, USA (MWK).

BEST DEVELOPMENT PRACTICES (BDPS) FOR CONSERVING POOL-BREEDING AMPHIBIANS IN NORTHEASTERN UNITED STATES

Vernal pools, and the adjacent terrestrial habitats used by amphibians during the non-breeding season, often overlap with land slated for residential or commercial development. Loss of non-breeding habitat is threatening pool-breeding amphibian populations. The Wildlife Conservation Society, Maine Audubon Society, and the University of Maine have developed Best Development Practices (BDPs) to provide a pragmatic approach to stewardship that encourages communities to identify their vernal pool resources, identify ecologically significant pools, and develop protection strategies. These BDPs, developed with input from regional vernal pool ecologists, resource managers, and the development community, provide information for two levels of conservation: 1) town-wide pool conservation planning (the ultimate goal) and, 2) conservation of individual pools (immediate implementation). A vernal pool assessment worksheet is included for assessing pools of conservation priority from the highest conservation value (Tier 1) to the least value (Tier III). Three ecologically sensitive zones were identified: the vernal pool depression, the vernal pool envelope (100 foot radius around the pool in spring high water), and the critical terrestrial habitat (100-750 feet). Specific recommendations for zone development activities including construction, stormwater management, and site clearing, are provided. Implementation of these guidelines will prolong the presence of pool-breeding amphibian populations in developing landscapes.



17.15 - 17.30
MITCHELL, NICOLA J., Fred W. Allendorf, Susan N. Keall and Charles H. Daugherty. School of Biological Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand, <nicola.mitchell@vuw.ac.nz> (NM, SK, CD), Division of Biological Sciences, University of Montana, Missoula, Montana 59812, USA (FA).

WHAT ARE THE CONSEQUENCES OF LOW FECUNDITY AND MALE-BIASED SEX RATIOS FOR THE WORLD'S RAREST TUATARA?

Effective population size (Ne) is an important concept in the management of threatened reptiles such as tuatara (Sphenodon spp.). Overlapping generations complicate any estimates of Ne for tuatara because they are slow to mature and long-lived. The single breeding population of Gunther's tuatara, Sphenodon guntheri, occurs on a four-hectare offshore island in New Zealand, and numbers about 500 individuals. Two features of this population are unusual: fewer than 10% of females breed each year, and males constitute 62% of the adult population. Females nest on the warm northern face of the island, and because hatchling sex is determined by the temperature of the nest (temperature-dependent sex determination, or TSD), warm nest sites produce predominantly male hatchings. We use generalised, age-structured simulation models to relate Ne to adult numbers under a range of population structures, including those that might be produced by global warming. Further, we discuss how management of the population (e.g., artificially incubating eggs to produce females) might help maintain adaptive genetic diversity.

Last updated: 02.07.02