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Discovery Southeast Founded in 1989 in Juneau and serving communities throughout Southeast Alaska, Discovery Southeast is a nonprofit organization that promotes direct, hands-on learning from nature through natural science and outdoor education programs for youth and adults, students and teachers. Discovery Southeast naturalists aim to deepen the bonds between people and nature. (907) 463-1500 fax 463-1587 [email protected] www.discoverysoutheast.org PO Box 21867 Juneau, AK 99802 Contents Introduction ..................................................................................................... 2 1 Methods ....................................................................................................... 5 Initial pond mapping with GIS and photointerpretation ................................ 5 Selection of study ponds ............................................................................. 6 Pond habitat assessments .......................................................................... 8 Amphibian surveys .....................................................................................10 Temperature loggers ..................................................................................13 Atlas of SE Alaskan amphibian records ....................................................15 2 Juneau area breeding pond survey .........................................................17 3 Aquatic vegetation ....................................................................................21 Submerged .................................................................................................21 Floating-leaved ...........................................................................................23 Emergent ....................................................................................................24 Bank vegetation ..........................................................................................25 4 Pond origin types ......................................................................................27 Human ........................................................................................................28 Beaver ........................................................................................................30 Glacial .........................................................................................................32 Uplift ...........................................................................................................35 Fen .............................................................................................................38 Bog .............................................................................................................42 Bedrock ......................................................................................................43 Riverside .....................................................................................................45 5 Amphibian natural history observations .................................................51 Western toad ..............................................................................................51 Wood frog ..................................................................................................57 Columbia spotted frog ................................................................................59 Pacific chorus frog .....................................................................................60 Long-toed salamander ...............................................................................60 Rough-skinned newt ..................................................................................61 6 Synthesis and recommendations ...........................................................63 Findings .....................................................................................................63 Recommendations for future work ............................................................65 7 Acknowledgments ....................................................................................65 8 Annotated references ..............................................................................67 Appendix A Pond assessment form ..........................................................73 1 Introduction Southeast Alaska’s amphibians Six species of anecdotal reports from Ketchikan to Haines point to a amphibian are considered native to Southeast Alaska. The dramatic drop in numbers of western toad, a species with three known anurans are western toad* (Bufo boreas), well-documented declines elsewhere in its range. In light of wood frog (Rana sylvatica), and Columbia spotted frog (R. growing amphibian conservation concerns both locally and luteiventris). Three known urodeles are rough-skinned worldwide, there is a need for basic information on newt (Taricha granulosa), long-toed salamander (Am- population status and the kinds of habitats that are bystoma macrodactylum) and northwestern salamander (A. occupied in Southeast Alaska, where exceptionally pristine gracile). In addition to these native species, two frogs from areas alternate with heavily roaded and logged watersheds. the Pacific Northwest have been introduced: Pacific chorus There is an equally strong need for conservation assess- frog (Pseudacris regilla, formerly Hyla regilla) and red-legged frog (Rana aurora). Of the 8 species of amphib- ians documented in Southeast Alaska, only western toad and rough-skinned newt are widely distributed throughout the mainland and islands of the Alexander Archipelago. Wood and spotted frog and long-toed salamander are reported chiefly in areas with transmontane river systems such as the Taku and Stikine that connect Southeast Alaska to centers of their distribution. Local populations of all but wood frog are near the northern edges of their geographic ranges. All 8 Southeast Alaskan amphibian species require ponds or other still waters for breeding. But the ecology of small ponds – particularly those lacking perennial connections to fish streams – has Checking traps at a rough-skinned newt breeding pond, June 11, 2003. Bog received almost no scientific study buckbean in lower left, yellow pond lily in lower right. in our region. Amphibian conserva- tion (and that of other pond organisms such as dragon- ment and recommendations, especially in areas of high flies) demands a better understanding of pond morphology, human activity. function, origin and diversity in Southeast Alaska. Habitat-based study From April 2002 to October 2003, Populations of amphibians have declined dramati- on contract with the Alaska Dept of Fish and Game cally around the world in recent decades. A variety of (ADF&G) we studied 5 native and one introduced amphib- possible causes have been cited, including habitat loss, ian species and their habitats near Juneau. The primary increased UV-B radiation, fungal infection, intensified objectives of our studies were: predation by introduced fish and nonnative frogs, climate change, increased risk of disease, damage to immune 1) to describe amphibian breeding distribution and systems resulting from pollutants such as pesticides, and the diversity of available pond habitats in the Juneau area combinations of these factors. and; Many large islands in Southeast Alaska have never 2) to refine habitat-based survey methods to be used been surveyed for amphibians, and only rudimentary across Southeast Alaska in the future. species range maps are available for this region. But * Alaskan literature including O’Clair et al. (1996) generally refers to Bufo boreas as the “boreal toad.” While this name has more flair than plain old “western toad,” we have decided to use the latter name for two reasons. First, while the range of B. boreas does extend slightly into boreal latitudes within interior British Columbia and extreme southern Yukon, the bulk of its distribution is within the western United States. Second, until recently this species has been largely neglected by northern researchers, whereas many papers have come out of California, Colorado, New Mexico, Oregon, Utah and Wyoming, especially in reference to the toad’s decline (Stebbins and Cohen, 1995). Most of these papers (Colorado excepted) call B. boreas the western toad. 2 our own experiences and those of dozens of Juneau Most of the diverse pond types used by breeding residents leave little doubt that western toad is in serious amphibians in Southeast Alaska can be found along the trouble in our area. Juneau road system. Results from our fairly localized study Although some of the suspected causes of popula- should help in the design of future more widespread tion decline cited above seem unlikely to apply to South- surveys, and in the interim, give some predictive power to east Alaska, an increase of disease seems a good candi- land managers concerned with possible impacts of habitat date. Chytridiomycosis – an unusual fungal infection disturbances to amphibian populations. caused by a parasitic water mold that attacks keratin in We assembled detailed habitat descriptions of 95 amphibian skin – is a possible proximate cause of regional occupied and unoccupied ponds and lakes in northern declines, possibly exacerbated by warming climate. Southeast Alaska. Most were within one half mile of Some of the western toad larval aggregations we Juneau roads. Juneau allows quick access to many located are so small and easily captured that collectors amphibian habitats at a logistically feasible

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