Conventional Herpetological Inventory
To complement my local knowledge work with amphibians on the Stikine as well as several years of opportunistic sampling, I am also undertaking conventional herpetological inventories in the area both to expand the available data and to compare results with those of the other project components. A special note of thanks must be extended to my volunteer and guide Seth Perry of Petersburg, Alaska who has generally donated his time and use of his boat for this project.
The last large-scale systematic amphibian inventory of the Stikine region occurred under two studies in the early 1990s by respected biologists Dana Waters (CLICK HERE TO DOWNLOAD WATERS' 1991 REPORT) and Norman Bradley. In the subsequent twenty plus years only sporadic reports of individual amphibians were recorded. To rectify this, I conducted a survey of several of the 1991 sites in early May of 2012. Another inventory of those sites and several others will take place in early June of 2013.
The Alaska portion of the Stikine River is a dynamic system with very different conditions between its tidally influenced mouth and upriver locations making amphibian inventories a challenge, especially if a goal is to intercept species during the peak of their breeding season. Snow melt and river levels are highly variable from year to year. Additionally, one must follow the tide tables to anchor in tidally influenced areas, restricting efficiency. Given that the 2011/2012 winter was particularly harsh, snow melt and river level rise occurred late at upriver sampling sites. During sampling, amphibian chorusing, breeding and egg laying was well underway at the mouth of the river while sites above the tidal influence were largely snowed in, with amphibians presumably still in their winter dormancy, except at sites with geothermal activity. Given the milder winter in 2012/2013 and the later start date of my inventory, I expect to intercept amphibian breeding at the upriver sites during this upcoming attempt.
The sites sampled in the 2012 inventory include Cheliped Bay, Dry island, Farm Island (Binkley Slough / Knig Slough), Limb Island, Little Dry Island, Mallard Slough, Mitkof Island (Blind Slough / Baseball Field Muskegs), Shakes Hot Springs, the Desert, Twin Lakes, and Wrangell Island (Earl West Cove / Middle Ridge / Muskeg Meadows golf Course / Pat's Lake / Salamander Creek / Wrangell Reservoir). Several additional upriver sites were intended to be sampled but these areas were still frozen in at the time of the visit. In 2013 the additional sites will include Andrew's Creek, Barnes Lake, Red Slough, and Shakes' Slough areas. Mitkof and Wrangell Island sites will not be a part of the second inventory.
By revisiting the 1991 sites, I was able to verify the persistence of previously reported populations and to identify previously unreported species. Although my inventory was far more limited in scale and duration, several important findings were elucidated as listed below.
NOTE: I intend to publish the results of these studies within my dissertation and peer-reviewed journals, and so I ask that site visitors please respect the intellectual property rights to these by refraining from directly publishing them elsewhere or using the information without prior written permission.
• Long-toed salamanders are abundant at Mallard Slough and Cheliped Bay
• Wood Frogs breed in Cheliped Bay, Dry Island and Farm Island grassland ponds
• Columbia Spotted Frogs could not be located at Mallard Slough and Cheliped Bay. They have however been confirmed on Wrangell Island.
• Long-toed Salamanders can by found on Little Dry Island (new record)
• Twin Lakes is home to several breeding populations of amphibians even before the lakes fill to capacity in late spring
• Long-toed Salamanders are present in the Twin Lakes vicinity even though they were suggested to be "extirpated" when they could not be located in 1991
• Northwestern Salamanders were not located bringing into question a 1991 unsubstantiated report of an egg mass in the Twin Lakes area
• Rough-skinned Newts were found to breed in geothermal ponds in the Twin Lakes Area. They were also found to breed and occur in abundance at Middle Ridge, Pats Lake, and the Wrangell Reservoir.
• Boreal Toads utilize the Shake's Hot Springs stream for breeding very early in the season. All stages of toad were found in extremely warm temperature.
• Boreal Toads and Columbia Spotted Frogs are both present in Shake's Hot Springs though adults tend to frequent cooler downstream localities
• Both Shake's Hot Tubs and Twin Lakes vicinities are hotspots for amphibian activity as suggested by local knowledge reports. They are also areas with high human-amphibian interactions based on their recreational opportunities
• Areas of Mitkof Island that have been suggested to be of historic amphibian abundance appear to have reduced amphibian populations. An opportunistic survey of these sites in 2010 resulted in a similar conclusion.
• Rough-skinned Newts and Boreal Toads are abundant on Wrangell Island and frequent the Muskeg Meadows Golf Course.
• Columbia Spotted Frogs were not located on Wrangell though a local policeman submitted a voucher photograph from the Muskeg Meadows Golf Course taken in 2009.
These are just a few of the highlighted findings from this study. A multitude of data is currently being entered and analyzed that will be published in coordination my dissertation in peer-reviewed journals. The study can be considered a major success and will be useful in determining the real and perceived health of several amphibian species in the region. The additional data from the upcoming 2013 inventory will be added to and compared with the 2012 data.
2012 Results Abstract
Amphibians are an import component of the socio-ecological system of the Stikine LeConte Wilderness and provide cultural, aesthetic, educational and recreational ecosystem services to the residents of this region. In order to corroborate local knowledge reports of these species and to compare the results of a systematic amphibian inventory conducted in 1991, I inventoried several sites of known amphibian abundance. Combined with local knowledge, this systematic inventory has provided substantial insight on the presence, abundance and health of local herpetofauna. Several species were identified including the Rough-skinned Newt, Long-toed Salamander, Wood Frog, Columbia Spotted Frog and Boreal Toad. Some of these were identified in previously unreported locations or where they were considered possibly extirpated. Rough-skinned Newts, Boreal Toads and Columbia Spotted Frogs were observed utilizing natural hot springs as breeding sites. Amphibians appear to be particularly diverse and abundant in the grasslands and wetlands of Farm Island, Mallard Slough, Twin Lakes, Shake’s Hot Springs and Wrangell Island’s Muskeg Meadows Golf Course. Most populations identified in 1991 locations were re-identified at the sites that I visited, suggesting long-term population stability. Sites on Mitkof Island that are known locally to be “amphibian hotspots” resulted in a limited number of observations both during the present study and during my 2010 opportunistic survey, indicating possible declines on this human-populated island. Future studies should consider visiting more sites with increased frequency throughout the year in order to fully comprehend amphibian-breeding phenology, species diversity and population patterns within this region.
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