Effects of Experimental Clearcut Logging on Gray Treefrog (Hyla versicolor) Tadpole Performance D. J. HOCKING 1 AND R. D. SEMLITSCH University of Missouri-Columbia, Division of Biological Sciences, 105 Tucker Hall, Columbia, Missouri 65211 USA ABSTRACT.—Clearcutting detrimentally affects the populations of many amphibian species. However, Gray Treefrogs (Hyla versicolor) have shown a preference for breeding sites located in clearcuts near forested habitat. To ; test the implications of this preference, we examined Gray Treefrog tadpole performance in cattle tanks along a gradient from clearcut to forest habitat. We replicated this design at three experimental clearcut sites. Tadpole performance was measured as length of the larval period, size at metamorphosis, and survival. We also examined the influence of temperature, periphyton productivity, and invertebrate predator abundances on tadpole performance. Time to metamorphosis was shorter in the clearcuts, but metamorphs tended to be smaller than metamorphs in the forest tanks. Survival was also greater in the clearcuts than in the forest treatments. Higher temperatures in the clearcuts primarily contributed to tadpole performance whereas invertebrate predators did not appear to influence performance. Although clearcuts benefited tadpoles through higher survival and shorter larval periods, there are potential fitness consequences for small metamorphs emerging in clearcuts. Habitat loss and alteration are among the greatest threats to biodiversity and are a major cause of amphibian declines (Wilcove et al., 1986; Semlitsch, 2003; Lannoo, 2005). With rapidly increasing human populations, the need for natural resources such as timber is also on the rise. Desire for profits from high-demand timber products stimulates logging practices that often result in reduced amphibian diversity and abundance (reviewed in deMaynadier and Hunter, 1995; Cushman, 2006). However, the mechanisms responsible for such declines re- main poorly understood (Cushman, 2006). Most studies investigating the effects of forest man- agement on amphibian demography have fo- cused on woodland salamanders and the terrestrial stage of pond-breeding species (Ash, 1995; Chazal and Niewiarowski, 1998; Kar- racker and Welsh, 2006; Todd and Rothermel, 2006). Few have investigated the potential impacts on the aquatic larval stage of amphib- ians (but see Wahbe and Bunnell, 2001). However, both the terrestrial and aquatic life stages of pond-breeding amphibians may be influenced by timber harvest and are important in population dynamics. The larvae of pond-breeding amphibians are confined to ponds until metamorphosis, which subjects them to changing aquatic conditions. The larval stage is dedicated to growth and exploits transient aquatic resources (Wilbur and Collins, 1973; Wilbur, 1980). Species differ in the duration of their larval stage depending on the predictability and quality of the aquatic re- sources, particularly the hydroperiod (Alford and Harris, 1988; Alford, 1999; Ryan and Winne, 2001; Skelly 2001). The duration of the larval period and the size at metamorphosis depend on both biotic and abiotic conditions in the pond. The time and size at metamorphosis are directly related to fitness in some pond-breed- ing amphibians. For some nonpaedomorphic species, individuals that metamorphose earlier and at a larger size reach maturity sooner and have larger clutch sizes (Smith, 1987; Semlitsch et al., 1988; Berven, 1990), although this has not been directly tested with Gray Treefrogs. Clearcutting around ephemeral ponds opens the forest canopy, which can alter resource availability for amphibian larvae. Tadpoles of some species grow faster and have greater survival in open canopy ponds compared with closed canopy ponds (Werner and Glennemeier, 1999; Skelly et al., 2002). Additionally, higher temperatures and food quality in open canopy ponds can positively affect tadpole performance (Schiesari, 2006). Therefore, clearcutting around ponds may be expected to improve the habitat quality for the aquatic larval stage of some anuran species. However, the open canopy created by clear- cutting can also alter predator communities in ponds. Anisopteran (Odonata) larvae are known to prey upon tadpoles (Semlitsch, 1990; Skelly and Werner, 1990; Petranka and Hayes, 1998). Many anisopteran species prefer to breed in open canopy ponds resulting in higher Journal of Herpetology hpet-42-04-10.3d 22/9/08 16:20:11 689 Cust # 07-294R1 1 Corresponding Author. Present address: Universi- ty of New Hampshire, 215 James Hall, Durham, New Hampshire 03824 USA; E-mail: dhocking@unh.edu Journal of Herpetology, Vol. 42, No. 4, pp. 689–698, 2008 Copyright 2008 Society for the Study of Amphibians and Reptiles