I. Conservative species, introduction.
Many plant and animal species are capable of inhabiting severely altered habitats in temperate regions (Wilhelm and Ladd 1988, Swink and Wilhelm 1994; Panzer et al. 1995, Reed 1996). These highly adaptable, "landscape-dwelling" organisms do not require reserves (or restorations) and occur in them simply as "samples" from broader regional landscapes. Conversely, there exists a subset of species that can be shown to be largely restricted in distribution to intact natural community remnants. Referred to as "remnant-dependent" (r-d) or "conservative" species (Wilhelm and Ladd 1988; Swink and Wilhelm 1994, Panzer et al. 1995, Panzer et al. 1997), these species serve, almost exclusively, to distinguish intact natural areas from developed landscapes, and comprise the bulk of the imperilled biodiversity in highly fragmented regions.
Methods. The identification and inventory of conservative species, a project long since completed for vascular plants (see Swink and Wilhelm 1994, Taft et al. 1997), is an essential prerequisite to sound reserve selection and management. We have surveyed one or more insect taxa in 76 prairie and savanna remnants since 1982 and have focused heavily on old field habitats since 1996, our goal being to identify and determine the status of the conservative insect species in our region. Survey methods have included sweep netting, vacuum collecting, and light trapping, as described in Panzer et al. (1995). Our surveys since 1996 have focused largely on grasshoppers, walking sticks, katydids, leafhoppers, froghoppers, planthoppers, butterflies, and 33 families of macro and micro moths. Our data, combined with reliable data from the Indiana Division of Nature Preserves (Bess 1998a, 1998b, 2000, 2001, 2005) represents the basis for the list of conservative species we present below.
Species Status. Scores of the plant species that inhabit the Chicago Wilderness Region are listed as Endangered, Threatened, or as Species of Concern by one or more of the three states within which the CW system occurs (Anonymous 1994). This action has spawned considerable interest in these species among governmental agencies, institutions, journalists and scientists, and has resulted in the emergence of many professional and amateur botanists who, in turn, have contributed substantially to plant community conservation in this region.
In comparison with plants, insects have been essentially ignored. State agencies, fearful of offending conservative legislators, steadfastly refuse to consider the listing of all but a handful of charismatic species (the Indiana Department of Natural Resources is forbidden by law to produce an official list of imperiled insects!). While most insect species have managed to persist on one or more sites, many do so as perilously small, isolated populations. The conservation of these species will require increasing interest and involvement among governmental agencies, scientists, and especially volunteer stewards. This is unlikely to occur until such time that insect species are included in official priority listings. With this goal in mind, we have summarized the regional status of those species considered to be imperiled in one or more Midwestern states, and have identified those species we consider to be endangered, threatened or of special concern within the diverse Chicago Wilderness Region.