Recovery Strategy for the Dakota Skipper (Hesperia dacotae) in Canada
The Dakota skipper formerly occurred throughout the dry-mesic mixed-grass and wet-mesic tall-grass prairies in southern Manitoba, North Dakota, eastern South Dakota, western Minnesota, Iowa, northern Illinois, and likely southeastern Saskatchewan, but it is now restricted to prairie remnants throughout its former range. Numerous local populations have been lost, including populations in southeastern Manitoba, and it is extirpated from Illinois and Iowa. In Canada, the Dakota skipper is found in two populations in south-central and southwestern Manitoba and one population in extreme southeastern Saskatchewan. The Dakota skipper was listed as Threatened in Canada under the Species at Risk Act in July 2005 and as Threatened in Manitoba in June 2007.
The Dakota skipper has one generation per year. In Canada, the adult flight period occurs from mid-June to late July. The peak flight season varies with spring weather conditions, but often occurs late-June or early-July. Adults live up to 4 weeks, and each female can produce up to 250 eggs in her lifetime. Once the eggs hatch, they go through six larval instars with a winter diapause at the fourth instar.
Dakota skippers may be found in two types of prairie: 1) low, wet-mesic tall-grass/bluestem prairie and 2) upland, dry-mesic mixed-grass/bluestem prairie. In Manitoba, in the wet-mesic tall-grass prairie, the adult Dakota skipper uses mainly black-eyed Susan, wood lily, harebell, and dogbane as nectar sources. In Saskatchewan, it uses mainly narrow-leaved purple coneflower as a nectar source. Dakota skipper larvae feed on a variety of grass species, but the preferred hosts are bunchgrasses, such as little bluestem and prairie dropseed. When not feeding, bunchgrasses provide an ideal structure for larvae to build their shelters due to the dense cluster of grass blades and the mass of persistent basal material; as well, bunchgrasses are a food source for the larvae, remaining edible into fall and in close proximity.
Threats to the Dakota skipper include 1) habitat loss through the conversion of prairie to cultivated land, 2) habitat degradation through burning, overgrazing, and haying, 3) habitat fragmentation, 4) changes in the plant community as a result of succession or invasion of exotic species, 5) the use of insecticides and herbicides to control pests and exotic plants, 6) climate change and natural disasters, and 7) the collection of natural history specimens.
Recovery of the Dakota skipper is deemed to be both biologically and technically feasible.
The overall recovery goal is to achieve a self-sustaining metapopulation of Dakota skippers in secure habitat distributed throughout their historical range in Manitoba and Saskatchewan. The short-term population and distribution objective is to maintain current population numbers and prevent any further loss of populations or distribution of the Dakota skipper in Canada.
The short-term recovery objectives are 1) Establish reliable population estimates for all Dakota skipper populations and assess viability under current conditions, 2) identify, secure, and enhance significant habitat for the Dakota skipper, and 3) increase knowledge of the Dakota skipper in Canada, including distribution, abundance, biology, and management practices.
The broad strategies to implement recovery and address threats include 1) a stewardship approach to secure important habitat, 2) population monitoring to more accurately estimate population sizes, trends, and area of occupancy, 3) habitat management to maintain the plant community required for Dakota skipper survival and reproduction, 4) research to fill gaps in knowledge on life history, and 5) a communication program to increase public awareness.
Critical habitat has not been identified for the Dakota skipper in this recovery strategy, but will be identified in an Action Plan, by the end of December 2010.
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