State of the Greater Fundy Ecosystem

GREATER FUNDY ECOSYSTEM RESEARCH PROJECT

UNB Faculty of Forestry and Environmental Management

State of the Greater Fundy Ecosystem

Amphibian Abundance within various
Terrestrial Habitats in the Vicinity
of Fundy National Park

Jill Adams1, Bill Freedman1, and Douglas Clay2
1Dept. of Biology, Dalhousie University, Halifax, N.S., B3H 4J1
2 Fundy National Park, P.O. Box 40, Alma, N.B. E0A 1B0

This study was undertaken to establish a methodology suitable for monitoring the abundance and communities of terrestrial amphibians in, and near, Fundy National Park (Fundy NP).

GOALS

The specific objectives of the work were:

1) To provide data on the abundance and species richness of amphibians in relation to terrestrial habitats.
2) To provide evidence of microhabitat preferences by terrestrial amphibians, using correlations between amphibian abundance and habitat variables.
3) To compare the abundance and diversity of amphibians in natural habitats versus human modified habitats, and to suggest reasons for observed differences.
4) To provide baseline data on amphibians in terrestrial habitats and to establish the basis of a long-term monitoring program in the Park.

METHODS

Sampling sites were chosen to represent the range of terrestrial habitat conditions present in Fundy NP and its immediately surroundings. Ten sites were investigated, representing habitat conditions ranging from natural forests to various human disturbed habitats, such as forest plantations, a regenerating gravel pit, and an abandoned pasture (see Table 1 for brief site descriptions).

The following methodologies were used to sample species richness and abundance of amphibians in the study sites:

1) Pitfall traps (transect) - During the 1995 growing season, pitfall traps were set up in 200-m-long transects and/or two 100-m-long transects in each of ten sites. The pitfall traps were constructed of 4- or 6-litre plastic buckets, placed in the ground with the opening flush with the surface. Traps were covered with a 40 cm x 40 cm piece of plywood.
2) Pitfall traps (array) - Two pitfall arrays were set up at each site in May 1996. Each array consisted of 30-cm-high and 5-m-long drift fences arranged in a Y-formation, with 3 pitfall traps in the center of the array and one at each end.
3) Time-constrained surveys - Two searches were done at each site in 1996. These searches were conducted during rainy weather by two surveyors, each searching for amphibians for a pre-determined length of time in moss, leaf litter, and coarse woody debris, under rocks, and along stream and pond banks.
4) Quadrat searches - Five searches were done at each site in 1996, with two 5 m x 5 m quadrats examined per search. Cover and other environmental variables were recorded for each quadrat prior to the search

A number of elements of microhabitat were recorded at each site. Percent cover of ground vegetation was estimated in 5 m x 5 m quadrats within the following categories: conifer >2m, conifer <2m, angiosperm >2m, angiosperm <2m, moss, fern, leaf litter, bare ground, coarse woody debris, and rock. Other environmental variables were measured in 1 m x 1m plots, including canopy (overhead) cover, soil pH, soil temperature, soil moisture, substrate resistance, and air temperature. All environmental variables were measured in 1996.

Red -spotted Newt (eft stage)(Photo: M. Burzynski)

RESULTS

Because this project is ongoing, the data analysis is incomplete. However, some general conclusions can be made regarding amphibian species presence and abundance among the sites, and the effectiveness of the methodologies used.

Table 2 shows the relative abundance of amphibian species in each site in 1995, as measured using pitfall traps (transects). Site 5 (an abandoned gravel pit) showed the greatest diversity of terrestrial amphibian species, likely because of its close proximity to a breeding pond. No amphibians were collected at sites 3, B, or D (representing a mixed forest, an abandoned pasture, and a 36-year-old Red Spruce plantation, respectively).

Because of the small numbers of amphibians caught in 1995, it was decided to use a variety of techniques during the 1996 field season. This allowed us to successfully capture more amphibians, and therefore to sample the sites more adequately. At least one species of terrestrial amphibians was present at all sites. However, Red-backed Salamander, a wholly terrestrial species, was not detected in any of the disturbed sites, which likely indicates a lack of adequate habitat.

Pitfall arrays were the most effective technique for sampling terrestrial amphibians. Pitfall transects also worked well, but they caught fewer amphibians per unit of effort. Quadrat searches were most important for capturing Red-backed Salamander, a species that moves infrequently and is able to climb out of pitfall traps (personal observation). Time-constrained searches caught the least number of amphibian species, and were also the most destructive sampling method because the area examined was not restricted.

IMPLICATIONS FOR MANAGEMENT

Further examination of the data will provide information on the habitat requirements of amphibian species, allowing for recommendations to be made regarding forestry practices and other habitat-altering activities. At this time, some preliminary recommendations can be made.

(1) When conducting long-term monitoring of terrestrial amphibians, pitfall arrays combined with quadrat searches should be used. These techniques will sample the greatest number and diversity of amphibians and therefore provide the best data.
(2) Forestry practices should be examined to see whether critical elements of habitat are lost, preventing terrestrial amphibians from utilizing those modified habitats.

ACKNOWLEDGMENTS

Persons that helped to make this project possible include Richard Wassersug, Alan Pinder, Frances MacKinnon, and other participants employed by Fundy NP. The support and encouragement of fellow graduate students is also appreciated, including Tracy Fleming, Greg Johnson, Minga O'Brien, and Cam Veinotte. Funding for this project was provided by a Dalhousie University Graduate Fellowship, contracts with Parks Canada, and the Natural Sciences and Engineering Research Council of Canada.

Further Reading:

Adams, J.D. 1997. Amphibian abundance and diversity in ten terrestrial habitats within and in the vicinity of Fundy National Park, New Brunswick. M.Sc. Thesis, Dalhousie University, Halifax, N.S. 126 pp.

Clay, D. and J. Brownlie. 1996. Status of amphibians and reptiles of Fundy National Park and its greater ecosystem. In: D. Clay (ed.) Resources of Fundy National Park: A primer of ecosystem studies. Part II. Chapter I. Pks. Can. Eco. Sci. Rev. Rept. No.2. 38 pp.

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