Tailed frogs: distribution, ecology, and association with timber harvest in northeastern Oregon.

Abstract

SummaryBull, Evelyn L.; Carter, Bernie E. 1996. Tailed frogs: distribution, ecology, and association with timber harvest in northeastern Oregon. Res. Pap. PNW-RP-497. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 11 p.Tailed frogs (Ascaphus truer) were found in 42 of 80 streams surveyed in Union, Umatilla, Wallowa, and Baker Counties in 1992. At least three size classes of larvae were identified in seven of the streams, thereby suggesting that larvae transform after spending 3 or more years in the streams. The amount of cobble and fines in the streambed best predicted abundance of larvae, whereas, cobble, boulders, slope gradient, and stream buffers best predicted abundance of adults.Keywords: Amphibians, Ascaphus, northeastern Oregon, tailed frog, timber harvest.This study was designed to investigate the distribution, abundance, life history, and effect of timber harvest on tailed frogs. In 1992, 80 streams in northeastern Oregon were surveyed for tailed frogs. More intensive surveys (diurnal searches for larvae and nocturnal searches for adults) were conducted in 30 streams in 1993.Tailed frogs were found in streams in four counties (Union, Umatilla, Wallowa, and Baker Counties) in northeastern Oregon. Their presence in three of these counties was previously unknown.Tailed frog adults and larvae were present in streams all summer. It appeared that three or more age classes of larvae were present in most streams, thereby suggesting that larvae are in the streams at least 3 years before they transform into frogs. Transforming larvae were found in streams in July, August, and September; none was found in October. There were no significant differences in numbers of larvae or adults in streams with a low, moderate, or heavy amount of timber harvest; however, there was a general downward trend in the abundance of tailed frogs as the amount of timber harvest increased.It appeared that stream characteristics were more important than landscape characteristics in predicting the abundance of tailed frogs in streams. Stepwise regression selected the two-variable model by using the amount of cobble and fines in the streams as best able to predict larval abundance. For adult frogs, the best model was a four-variable model with the stream buffer, amount of boulders and cobble in the stream, and the slope gradient being the variables best able to predict the abundance of adult frogs.

Effects of uneven-aged timber harvest on forest floor vertebrates in the Cascade Mountains of southern Washington

“…Some studies reported little to no effect (West et al, 1980;Bull and Carter, 1996;Messere and Ducey, 1998;Gitzen and West, 2002;Hicks and Pearson, 2003;Frederickson and Frederickson, 2004;Fuller et al, 2004), others negative effects (Duguay and Wood, Wolff and Zasada, 1975;Waters and Zabel, 1995;Naughton et al, 2000;Morneault et al, 2004), and others still, positive effects (Von Treba et al, 1998;Ross et al, 2000;Fuller et al, 2004). These mixed findings are due to several factors.…”

“…In a literature review, deMaynadier and Hunter (1995) identified only one study of the effects of uneven-aged harvests on amphibians. I found nine published studies that sampled amphibians in selectively harvested stands or landscapes (Bull and Carter, 1996;Messere and Ducey, 1998;Naughton et al, 2000;Ross et al, 2000;Duguay and Wood, 2002;Hicks and Pearson, 2003;Frederickson and Frederickson, 2004;Morneault et al, 2004). In addition, I also found nine studies on small mammals in selectively harvested stands (Wolff and Zasada, 1975;West et al, 1980;Waters and Zabel, 1995;Von Treba et al, 1998;Carey, 2000;Sullivan and Sullivan, 2001;Gitzen and West, 2002;Klenner and Sullivan, 2003;Fuller et al, 2004).…”

“…It is often difficult, however, to accurately position studies along this gradient because of incomplete descriptions of harvest methods, wide variation in harvest equipment/methods even within one category, and the spatial extent (stands versus watersheds) of experimental units (e.g. Bull and Carter, 1996). In addition, although most ecologists would agree that site productivity could play a major role in determining the magnitude and effect of timber harvest on wildlife, site productivity has rarely been considered.…”

The habitat ecology of the post-metamorphic coastal tailed frog (Ascaphus truei).

“…Given the observed declines of southern populations following anthropogenic disturbances (Hawkins et al 1988;Bull and Carter 1996;Hawkes and Gregory 2012), there is concern that tailed frogs at the northern extent o f their distribution may also be negatively affected by activities such as forest harvesting, stream diversion, or the creation o f linear corridors. However, the possible impacts are speculative as our knowledge o f habitat requirements for the terrestrial life-stage of the species is limited.…”

“…Breeding occurs in early fall (September to October) depending on the geographic location (Green and Campbell 1984). The genus has evolved internal fertilization as a reproductive strategy because breeding occurs in flowing streams or small pools close to larval streams (Green and Campbell 1984;Bull and Carter 1996;Ritland et al 2000). Clutch sizes for A. truei range from 44-85 eggs deposited in double strands under rocks in cool-flowing streams ) from late June to early July following the fall breeding.…”