The Lynnville-Squaw Creek Important Bird Area is located in rural Warrick County in southwestern Indiana. Formerly a surface coal mining operation, the site?s habitat was created via the current practice of coal mine reclamation in which graded areas are planted with cool-season exotic grasses, such as tall fescue and smooth brome. Owned and managed by both the Peabody Coal Company (northern section) and the Squaw Creek Coal Company (southern section), this IBA is one of the largest reclaimed grasslands in Indiana at roughly 7000 acres in size. Because nearly 6000-acres of this habitat are relatively undisturbed, the area likely supports the largest populations of grassland birds in the southwestern section of the state.
Due mostly to the loss of native and non-native prairie-type habitats in the Midwest, many species of obligate grassland birds have undergone significant population declines in recent decades. Countering this trend in grassland decline is the relatively new process of surface mine reclamation that revegetates recently disturbed areas with non-native cool season grasses, thereby creating refuges for birds that originally occupied the midwestern tallgrass prairie. The Lynnville-Squaw Creek mine complex contains the largest acreage of undisturbed grasslands when compared to other reclaimed surface mines in southwestern Indiana and subsequently supports some of the most abundant populations of obligate and facultative grassland birds in Indiana.
Research performed by scientists from Indiana State University in the late 1990s helped quantify the important relationship of the reclaimed coal mine grasslands with bird conservation. From their published data, it is shown that the Lynnville-Squaw Creek IBA contains what is perhaps Indiana's second largest population of Henslow's Sparrow, a WatchList species and one of great global conservation concern. In all, more than 200 pairs of this endangered bird likely breed here. The Dickcissel, another WatchList species and one which is dependent on grassland habitat during the nesting season, is especially abundant at this mine, with an estimated 500 breeding pairs. Several other declining grassland and brushland species also breed in the Lynnville property, including Northern Bobwhite, Willow Flycatcher, and Bell's Vireo, the latter two species also belonging to Audubon's WatchList. Grasshopper Sparrow and Eastern Meadowlark are probably the most prolific of any grassland bird at this IBA, though, with breeding pairs numbering at approximately 1000 for each species. In addition, the small wetlands here may harbor additional species which are considered endangered in Indiana, like American Bittern, Least Bittern, and King Rail.
Although much of the Lynnville-Squaw Creek property is still held in bond by the respective coal companies, the majority of the area will likely be released in the coming few years and be available for purchase. As with many other reclaimed mines considered either potential or recognized IBAs in southwestern Indiana, the gently rolling hills and vast grasslands of Lynnville and Squaw Creek area are judged as ideal locations by county officials for future developments, such as residential communities or industrial parks. These types of developments would significantly decrease the amount of available habitat for nesting grassland birds, thereby making the property less appealing to area-sensitive species. Development would also fragment the remaining natural landscape, which would make the grasslands more susceptible to succession and invasion by woody vegetation.
Additionally, since much of the acreage is covered in herbaceous vegetation, the possibility of sale to grassland farming operations and subsequent agricultural intensification, such as increased haying and grazing, are always present. Although these practices may not necessarily increase the rate of habitat fragmentation, mowing and cutting repeatedly during critical periods within the nesting season is a pervasive agricultural activity at many of Indiana?s reclaimed grasslands. If practiced in the future at the Lynnville-Squaw Creek IBA, such untimely harvesting could produce an overall decline in nest productivity and severely affect the success of what is likely one of the largest breeding grassland bird communities in Indiana.
The Lynnville Mine (1830 Ha) is owned and managed by the Peabody Coal Company. The Squaw Creek Mine (1000 Ha) is owned and managed by the Squaw Creek Coal Company.
Despite a superficial appearance of homogeneity, the mine grassland vegetation varies sufficiently to affect local abundances of birds. Eurasian cool season grasses such as tall fescue and smooth brome, prominent in seed mixtures planted decades earlier, still comprise 64% of the grassland canopy cover. Forb cover averages 27%, with as much cover by native invaders such as goldenrod as by legumes planted during the reclamation.
The mine wetlands at Lynnville vary in size and include seasonal, semi-permanent, and permanent wetlands. Most are generally well-established, and contain large portions of open water along with thick stands of emergent vegetation.