The Minnehaha Fish and Wildlife Area and the Dugger Unit of the Greene-Sullivan State Forest are located in southwestern Indiana in Sullivan County. Ironically, despite being part of the Central Hardwoods Region, the overall landscape encompassed by the Minnehaha/Dugger IBA, with its large grasslands and rolling hills intermixed with marshes and ponds, more closely resembles a 'prairie pothole' habitat-type. The difference in habitat when compared to the expected forests of this particular ecological region is due to the fact that the Minnehaha and Dugger areas were once operated as large surface coal mines.
In all, the IBA encompasses more than 10,000 acres of land. Of this, over 3000 acres of habitat are considered undisturbed grasslands. Such pseudo-prairie habitats were created by the current practice of surface mine reclamation, in which disturbed areas are planted in a few species of Eurasian cool-season grasses for rapid establishment of ground cover to meet erosion-control guidelines.
The Dugger portion of this IBA is owned and managed by the Indiana Department of Natural Resources (IDNR) as a unit of the larger Greene-Sullivan State Forest, which is located separately to the southeast. The Minnehaha FWA is also managed by IDNR; however, the land is operated via a lease from the coal companies that formerly mined the area.
Many grassland species of the Midwest have undergone significant population declines in the last century largely due to the loss of native grassland habitat. In Indiana alone, the estimated historic reduction of native prairie is an approximate 90 percent. However, published studies conducted by researchers from Indiana State University show that the widespread grassland habitats in southwestern Indiana forged from coal mine reclamation support large populations of many obligate and facultative grassland species. Hence, the Minnehaha/Dugger IBA provides a major resource for many beleaguered grassland specialists and plays a major role in the conservation of 'prairie birds' in Indiana.
For example, among the breeding birds surveyed during comprehensive studies within the reclaimed mines, four grassland specialist species were among the most abundant on the counts - Eastern Meadowlark, Grasshopper Sparrow, Dickcissel, and Henslow's Sparrow. Each of these species is known to be declining throughout the Midwest, and the latter two birds (i.e., Henslow's Sparrow and Dickcissel) are included on Auduon's WatchList. Although not the most common of the four species within the IBA, estimates for Henslow's Sparrow show that over 100 pair probably nest at Minnehaha/Dugger, which is a significant portion of this bird's population in Indiana. Other WatchList species that nest at this IBA in smaller numbers include Willow Flycatcher and Bell's Vireo. Additionally, summer records exist at Minnehaha for American Bittern, Northern Harrier, and Short-eared Owl, all three of which are listed as state-endangered species in Indiana.
During the non-breeding season, the Minnehaha/Dugger IBA also supports one of the state's most significant populations of raptors. Many Rough-legged Hawks and Northern Harriers winter in these reclaimed mine grasslands, along with a notable contingent of Short-eared Owls during both fall migration and winter. Because of the various marshes and open water habitats which exist on the properties, Bald Eagles and Peregrine Falcons can also be found, particularly during the fall migration season.
Several conservation issues are pertinent to this Important Bird Area, but the primary concern is for the future and status of the Minnehaha Fish and Wildlife Area. The property is leased by Indiana's Department of Natural Resources from the Ayrshire Land Company, and the local county government has voiced opposition in the past to having IDNR acquire ownership of the area, arguing that this would decrease property tax revenue. Considering this lack of realization of the value of Minnehaha to the local economy in the form of hunting, fishing, and recreation, if IDNR is not able to permanently acquire the property in the future, continued pressure from county officials and local developers may lead to industrial, commercial, and residential constructions at the Minnehaha location, as has been experienced at many other unprotected mine grasslands in southwestern Indiana. Fortunately, at least, Dugger was acquired several years ago by the state and is considered protected from such pressures.
However, ownership is not the only threat to the grassland and wetland birds which utilize this IBA. Habitat succession and invasive non-native plant species are also a great concern. IDNR typically does not use prescribed burning as part of its management regime at its fish and wildlife areas, and the amount undisturbed grasslands, although still relatively large, has shown some slight declines over the past several years thanks to early succession and the increased establishment of pioneering shrubs and trees. Additionally, the amount of invasive plant species, well-illustrated by the abundance of fragmites in the wetlands of Dugger, poses a severe threat to available habitat for many breeding birds.