Karner blue butterfly habitat
The Karner blue butterfly's habitat once ranged from Minnesota to Maine and into Canada. Habitat loss, destruction, and fragmentation primarily due to natural succession, agriculture, and residential and commercial development caused the decline. Outside of Wisconsin, the Karner blue has been reduced to small populations in Indiana, Michigan, Minnesota, New Hampshire, and New York. Karner blues are considered extirpated in Massachusetts, Pennsylvania, Ohio, and Ontario.
In Wisconsin, the Karner blue butterfly usually occupies open barrens, savannas and prairies that contain wild lupine. This plant is widespread in Wisconsin’s central and northwest sands. The pale green caterpillar of the Karner blue feeds exclusively on the leaves of the wild lupine.
- Barrens - Barrens are plant communities that occur on sandy soils and are dominated by grasses, low shrubs, small trees, and scattered large trees. Noted University of Wisconsin ecologist John T. Curtis (1959) described these communities as pine barrens in northern and central Wisconsin and as oak barrens in southern and west-central Wisconsin. Because of their dynamic nature and the variability in structural types and species composition, they are difficult to describe and classify. Prior to Euro-American settlement, the vegetative structure of large barrens landscapes was quite variable and dynamic. Inclusions of variously sized and aged forest stands such as mature red pine, mature oak (bur, red, Hill’s, or black), aspen groves, and numerous wetlands were typical of most pine and oak barrens. Natural community information.
- Savanna - In the Midwest, savanna is generally used to describe an ecosystem that was historically part of a larger complex bordered by the prairies of the west and the deciduous forests of the east. This complex was a mosaic of plant community types that represented a continuum from prairie to forest. Savannas were the communities in the middle of this continuum. The mosaic was maintained by frequent fires and possibly by large ungulates such as elk. Oaks were the dominant trees, hence the term oak savanna. Natural community information.
- Prairie - Prairies are located mostly in the southern and western parts of the state and are divided into six different types. More than 400 species of native vascular plants are characteristic of Wisconsin prairies, and most are restricted to prairie and savanna community types. In addition to a varied plant community, prairies have a diverse and specialized fauna, especially among prairie invertebrates, prairie and grassland herptiles, and grassland birds. Natural community information.
- Other Habitats - Various remnants of these habitat types can be found on roadsides, utility right-of-ways, or other areas that are maintained in an open early successional stage. These corridors can provide an important link between larger habitat areas and encourage dispersal and genetic diversity.