Background: Projections of a rapidly changing climate and increasing human population have led to calls for broad-scale biodiversity assessments that can serve as benchmarks for identifying ecological change. Genetic tools have been used for such assessments for decades, but spatial sampling considerations have been overlooked.
Research: Research conducted by RMRS scientists demonstrates how intensive sampling efforts across a large geographical scale can influence identification of taxonomic groups among the fishes of the genus Cottus in the northern Rocky Mountains. Researchers used specific sequences from mitochondrial DNA regions and phylogenetic analyses techniques as indicators of biodiversity and to identify unique species. Analyses of linked DNA sequences from sculpin collected in all major watersheds within the study area revealed eight groups with species-level differences that were also geographically bounded by large geological features. Surprisingly, six of these groups could not be assigned to recognized species, despite North American fishes having been generally well inventoried in genetic surveys.
Management Implications: Cottus species have been widely acknowledged as being among the most taxonomically challenging freshwater fishes to identify; as such, there has been much confusion about the identity and distribution of many sculpin species throughout the U.S. Northern Rocky Mountains. This research brings some clarity to the taxonomic picture of stream dwelling sculpin, but many questions remain regarding genetically based identification and the desired spatial scale and grain of sampling. Genetic assessments based on spatially robust sampling designs will likely reveal previously unrecognized biodiversity in many other taxa.
For more information, see: http://www.fs.fed.us/rm/boise/AWAE/projects/fish_tissue_collection.html.