The Pleasant Run Unit Important Bird Area is the northernmost parcel of the larger Hoosier National Forest and is located along the convergence of Brown, Jackson, Lawrence, and Monroe Counties in south-central Indiana. Approximately 85,000 acres in size and consisting primarily of contiguous mid to late-successional forest, the Pleasant Runt Unit is one of Indiana?s most significant areas for forest-dependent songbird populations. Many of the state?s largest populations of breeding neotropical migratory birds, including WatchList species such as Cerulean Warbler, Worm-eating Warbler, and Kentucky Warbler, can be found within this IBA.
The majority of the land within this IBA is owned and managed by the U. S. Forest Service, although smaller parcels of privately-owned land are dispersed throughout the area. The landscape is characterized by hills and areas of extensive sandstone bluffs, steep-sided ridges, irregular and gently rolling lowland plains, and a small amount of bottomlands; the dominant forest type is oak-hickory, although beech-maple is a significant component as well. An interesting feature of the Pleasant Run Unit is the Charles C. Deam Wilderness Area, which totals an approximate 13,000 acres in size, and is Indiana?s only congressionally designated wilderness area and one of the largest contiguous tracts of wilderness in the Central Hardwood region. Such reserved forest land contributes appreciably to the conservation of neotropical migratory birds within this IBA.
Without question, the Hoosier National Forest supports the largest population of breeding neotropical migratory birds in Indiana and is probably one of the most productive areas for forest-dependent songbirds in the Midwest. From this large forested landscape, many intensive studies over the last decade by researchers have determined that that the Pleasant Run Unit provides a ?source? population for virtually all forest-dependent bird species. Furthermore, data obtained from the state?s Breeding Bird Atlas indicates that the Pleasant Run area has one of the highest nesting bird diversities in the state, and USGS Breeding Bird Survey routes confirm that this national forest unit is likely unparalleled in Indiana for abundance of breeding neotropical birds.
In all, approximately 25 bird species either listed as that of continental or regional concern are known to occur within the Pleasant Run Unit of the Hoosier National Forest, and no fewer than 8 WatchList species are confirmed to breed within this Important Bird Area - Red-headed Woodpecker, Wood Thrush, Blue-winged Warbler, Prairie Warbler, Cerulean Warbler, Worm-eating Warbler, Louisiana Waterthrush, and Kentucky Warbler can all be found here during the summer months. Several additional species listed as endangered by the Indiana Department of Natural Resources occur here during the breeding season as well, including Black-and-White Warbler and Hooded Warbler. Extrapolations from Breeding Bird Survey data also show that nesting pairs for several declining and forest-dependent species, such as Acadian Flycatcher and Scarlet Tanager, most likely number well into the thousands.
Most importantly, studies of the effects of landscape pattern and forest management activities within the region indicate that the contiguous percentage of forest cover (greater than 80%) has created a landscape that supports a source population for most, if not all, of these critical species. Because the mean forested patch size is quite large, local research has shown that negative reproductive success caused by nest depredation and cowbird parasitism is minimized when compared to fragmented habitats.
Estimates for relative abundance listed were calculated from density estimates for each species for the entire Hoosier National Forest (derived from Don Whitehead's research of forest fragmentation - personal communication).
The most immediate threat to the breeding population of neotropical migratory birds at the Pleasant Run Unit comes from potential changes in forest management practices. During the spring of 2005, the U. S. Forest Service published a Draft Environmental Impact Statement and corresponding Forest Plan which proposes several new management strategies for the area. If accepted, the preferred management alternative would increase timber harvest within Hoosier National Forest by approximately 30 percent. Studies conducted at the Pleasant Run Unit have shown that increased logging practices, including various timber-cutting regimes and the creation of wildlife openings, produce internal disturbances which eliminate habitat for forest-dependent birds and lower reproductive success in forest adjacent to the disturbances. Many breeding neotropical birds, including numerous species of vireos, thrush, warblers, and tanagers, could all be negatively impacted.
Additionally, management practices of both publicly and privately-owned properties adjacent to the Pleasant Run IBA can have negative impacts on forest-dependent birds. Many nearby state parks and recreation areas maintain short-grass landscapes, which is ideal habitat for Brown-headed Cowbirds, thus increasing the threat of parasitism in adjacent forested land. Also, state management of bottomland areas near Monroe Reservoir, just west of the IBA boundary, creates narrow forest corridors bordered by agricultural land which is leased seasonally to farmers. The narrow corridors adversely affect bottomland bird communities, and the farmland increases populations of cowbirds and potential nest predators.