Diversity and Activity of Ground-Dwelling Spiders (Araneae) in Four Sub-Communities in a Degraded Oak Woodland at the Chicago Botanic Garden, Cook County, Illinois

Ground-dwelling spiders were sampled using pitfall traps over a twelve-month period from four sub-communities within a 40-ha oak woodland complex in northern Cook County, Illinois. Mesic and dry mesic oak woodland, mesic upland forest, buckthorn dominated mesic oak savanna and a mesic woodland control, where no restoration management is planned, were sampled. Fifty-five species within 44 genera and 18 families were trapped. The results suggest negative correlations between non-native spider abundance and spider species richness. Also, phenology of the various species indicates that a year-round inventory is necessary to adequately sample ground-dwelling spider assemblages. Possibilities of using Bathyphantes concolor (Wider) abundance as an indicator of oak woodland recovery are discussed. Three species, Linyphiidae: Oreonetides vaginatus (Thorell), O. rotundus (Emerton), and Thomisidae: Ozyptila praticola C. L. Koch), never before recorded for Illinois were documented. The non-native species, Ozyptila praticola, is also a new regional record.