An assessment of survey methodology, calling activity, and habitat associations of wood frogs (rana sylvatica) and boreal chorus frogs (pseudacris maculata) in a tundra biome

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Title: An assessment of survey methodology, calling activity, and habitat associations of wood frogs (rana sylvatica) and boreal chorus frogs (pseudacris maculata) in a tundra biome
Author: Mannan, Robert Nicholas
Abstract: The tundra biome near Cape Churchill , Manitoba is being influenced by global climate change and herbivory from an increasing population of light geese . These environmental changes may impact anuran populations , although little is known about population trends in anurans in the region . The isolation of the region may render traditional anuran survey methods ineffective . I tested two methods of surveying for two anuran species , boreal chorus frogs (Pseudacris maculata ) and wood frogs (Rana sylvatica ) . I solicited calls from non -calling anurans by manually broadcasting conspecific advertisement calls , and I used automated audio recorders to increase survey coverage . I detected 0 .38 additional wood frogs per survey when broadcast calls were employed , compared to surveys without broadcasts . I was unable to detect additional boreal chorus frogs by broadcasting conspecific advertisement calls . Using automated audio recorders , I was able to identify anuran presence in a radius of 100 m , but detections of wood frogs were low compared to manual surveys . I suggest that broadcasts of wood frog advertisement calls be implemented into surveys for wood frogs in the tundra biome , and that additional research is necessary to determine whether solicitation can be used to increase detection of other anuran species . Chapter II Little information exists regarding wood frogs (Rana sylvatica ) and boreal chorus frogs (Pseudacris maculata ) in the tundra biome , where environmental conditions differ from most of the rest of their breeding ranges . Understanding anuran calling patterns is essential to most anuran survey methodology . During the summer of 2007 , I placed automated audio recorders at anuran breeding locations and recorded number of calling anurans near Cape Churchill , Manitoba . I used data loggers and automated call recorders to document date , time of day , temperature , and relative humidity . Automated recorders detected wood frogs between 30 May and 2 July 2007 , and boreal chorus frogs between 11 June and 5 July 2007 . Calling activity of both wood frogs and boreal chorus frogs was influenced by temperature and day of the year (DOY ) . Calling activity of boreal chorus frogs was also influenced by time of day and relative humidity . Understanding calling patterns with respect to weather patterns will facilitate future monitoring . Chapter III Anuran populations in the subarctic tundra biome in northern Manitoba are being impacted by multiple factors , including vegetation changes resulting from foraging pressure by an increasing population of light geese . During the summers of 2006 and 2007 , I surveyed 204 potential anuran breeding locations in two study plots in the tundra biome within Wapusk National Park , Manitoba , Canada to assess anuran habitat associations . I examined habitat selection and associations of wood frogs (Rana sylvatica ) and boreal chorus frogs (Pseudacris maculata ) with regard to vegetation and water quality . Both wood frogs and boreal chorus frogs selected sites where vegetation was taller and had a higher composition of sedge (Carex spp . ) and willow (Salix spp . ) . Both species also selected sites with relatively low pH and conductivity (TDS ) . An index of goose herbivory was negatively correlated with vegetation height and cover by sedge and willow and positively correlated with pH and conductivity . Both wood frogs and boreal chorus frogs were found more commonly in sites with less evidence of recent goose herbivory .
URI: http : / /hdl .handle .net /2346 /8517
Date: 2008-05

Citation

An assessment of survey methodology, calling activity, and habitat associations of wood frogs (rana sylvatica) and boreal chorus frogs (pseudacris maculata) in a tundra biome. Master's thesis, Texas Tech University. Available electronically from http : / /hdl .handle .net /2346 /8517 .

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