Brassy Minnow (Hybognathus hankinsoni) Conservation Status Review
Review Date = 04/08/2010
ScoreU - Unknown
ScoreG - 200,000-2,500,000 km squared (about 80,000-1,000,000 square miles)
Comment213,883 square kilometers based on Natural Heritage Program range maps that appear on the Montana Field Guide
Area of Occupancy
ScoreE - 100-500 km squared (about 25,000-125,000 acres)
Comment470 square kilometers based on Heritage range maps and occupancy of 1% of landscape by streams and occupancy of 22% of sites surveyed.
ScoreE - Relatively Stable (±25% change)
CommentEven though they have been impacted by grazing, exotic species, and some dewatering, prairie streams have probably been pretty stable in terms of water etc. since the arrival of Europeans within +/-25%
ScoreE - Stable. Population, range, area occupied, and/or number or condition of occurrences unchanged or remaining within ±10% fluctuation
CommentSince 1999, prairie fish surveys do not suggest decline as indicated by distribution data although this is not as sensitive to detecting decline as regular monitoring of a network of sites.
ScoreF - Widespread, low-severity threat. Threat is of low severity but affects (or would affect) most or a significant portion of the population or area.
CommentIntensive agriculture, overgrazing, road crossings, dams, and exotic species (Northern Pike in particular) all represent threats.
SeverityLow - Low but nontrivial reduction of species population or reversible degradation or reduction of habitat in area affected, with recovery expected in 10-50 years.
CommentSpecies is capable of recovering quickly if suitable habitat is available. Perhaps the majority of prairie streams affected by intensive agriculture are capable of recovering to the point of supporting populations within 50 years.
ScopeModerate - 20-60% of total population or area affected
CommentOne third of Brassy Minnow Range is subject to the presence of Northern Pike. Intensive agriculture probably threatens the species in 20% of its Montana Range. Intensive grazing is much more patchy, perhaps 5% of species range in Montana.
ImmediacyModerate - Threat is likely to be operational within 2-5 years.
ScoreC - Not Intrinsically Vulnerable. Species matures quickly, reproduces frequently, and/or has high fecundity such that populations recover quickly (< 5 years or 2 generations) from decreases in abundance; or species has high dispersal capability such that extirpated populations soon become reestablished through natural recolonization (unaided by humans).
CommentLongevity of 3-4 years
ScoreC - Moderate. Generalist. Broad-scale or diverse (general) habitat(s) or other abiotic and/or biotic factors are used or required by the species but some key requirements are scarce in the generalized range of the species within the area of interest.
CommentPresent in a variety of prairie stream sizes and substrates. Trend toward clearer streams, but seem to handle a variety of turbidities as well.
Raw Conservation Status Score
3.5 + 0.0 (area of occupancy) + 0.0 (environmental specificity) + 0.0 (short-term trend) + 0.0 (threats) = 3.5