Date of Award

5-2004

Level of Access

Campus-Only Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Wildlife Ecology and Wildlife Conservation

Advisor

Malcolm L. Hunter, Jr.

Second Committee Member

Phillip G. deMaynadier

Third Committee Member

John M. Hagan

Abstract

Riparian areas are one of the most complex, diverse, and dynamic environments in forested ecosystems. Amphibians are excellent candidates to study in riparian areas because they are sensitive to forest management, have high diversity in riparian areas, and are one of the most abundant vertebrates in temperate forests. I conducted a field experiment in which 15 headwater streams in western Maine were randomly assigned to five treatments, and I examined them for 1 year prior to harvest and for 2 years after harvests. I also undertook a retrospective study on 12 headwater streams representing three treatments where harvests had occurred 4-1 0 years earlier. I used pitfall traps and cover-controlled active-searches to sample terrestrial and stream amphibians to determine: a) if amphibians can define the riparian zone based on species occurrence and abundance; b) if and how different types of timber management affect amphibian communities; and, c) if sticks placed in pitfall traps will reduce the incidental capture and subsequent mortality of small mammals. In Chapter 1, I found total and average species richness was highest in the trap location located closest to the stream, and 3 species were caught almost exclusively on the banks adjacent to the stream. I conclude that the riparian zone as defined by amphibians along headwater streams is relatively narrow (8-9 m), yet distinguishable due to high diversity and unique species occurrence. In Chapter 2, I found wood frogs (Rana sylvatica), redback salamanders (Plethodon cinereus), and spotted salamanders (Ambystoma maculatum) all showed sensitivity to riparian forest management. American toads (Bujo americanzu) were either unaffected or increased in abundance after harvests took place. Buffers ranging in width from 11 to 35 m appeared to partially mitigate for the timber harvests, as abundances were generally higher within the buffer than in the adjacent clearcut for some species. Partial harvests had the least effect on the amphibian community and should be considered for harvests in riparian area. In Chapter 3, I found that the placement of sticks in pitfall traps is an effective method that reduces small mammal mortality without affecting amphibian capture rates, is efficient, and is inexpensive.

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