Aquatic Invertebrate Responses to Timber Harvest in a Bottomland Hardwood Wetland of South Carolina

We used aquatic invertebrates to assess environmental impacts of timber harvest on a bottomland hardwood wetland in the Coosawhatchie River floodplain, Jasper County, S C . Two years (1998, 1999) of preharvest baseline data were collected during winter floods in three ll-13-ha tracts of wetland forest. The following autumn of 1999 one tract was completely clearcut. In a second tract the majority of the area was also clearcut, but three 0.2-0.6-ha islands of intact forest were retained (i.e., patch-retention treatment). The third tract remained intact and served as the control. We continued to sample invertebrates in the three tracts for another 2 years (2000, 2001) after harvests. Invertebrate communities in the clearcut tract differed significantly from previous baseline conditions in that habitat and also from the nearby control tract. The patch-retention tract induced a lesser response than the clearcut, suggesting that retention islands helped mitigate impacts. Timber harvest caused a decline in some invertebrate populations (Asellidae, Crangonyctidae, Planorbidae), but an increase in others (Culicidae). Overall invertebrate abundance and family richness was not affected by harvest, only community composition. Invertebrate change probably reflected a conversion of a fauna typical of forested wetland to one typical of herbaceous wetland. FOR. SCI. 5 1 (4):284 -29 1.