Berendzen, P.B., T. Gamble, and A.M. Simons. 2003. The genetic status of northern cricket frogs in Minnesota. Final report submitted to the Nongame Research Program, Minnesota Department of Natural Resources. 43 pp.
The northern cricket frog has a small range in Minnesota, most records are from the southeast and southwestern regions of the state. Populations of these frogs exhibited a precipitous decline in the 1980's and by the mid 1990's the northern cricket frog was considered extirpated from Minnesota. In 1998, a chorus of northern cricket frogs was heard in Bloomington, Hennepin County, Minnesota. This population is far outside the historic range of northern cricket frogs and its proximity to a shipping depot and a large urban center raised concerns that these frogs may have been purposefully or accidentally introduced. To determine the origin of this population, we sequenced 725 nucleotides of the mitochondrial cytochrome b gene in 45 specimens of the northern cricket frog. These samples included five specimens from the Bloomington population as well as specimens from across the range of the species. We used phylogenetic and phylogeographic techniques to analyze these data to determine evolutionary relationships among populations and to examine the correlation of these relationships with geographic distribution. The Bloomington population has DNA sequences that are unique compared to other northern cricket frog populations. This population is genetically most similar to populations from Iowa, Wisconsin, and northern Illinois. Thus it is unlikely that the Bloomington frogs were introduced from a distant population. They may have been introduced from a population in the upper midwest but given their unique DNA sequences, we think it just as likely that these frogs are native to Minnesota. We recommend that these frogs be managed as a native endangered species. We further recommend that additional surveys be undertaken to discover other populations that may be present in the state.