In sandy bottom streams of the Coastal Plains ecoregion in the southeastern US, increased sediment deposition and altered hydrologic regimes associated with land cover change can reduce coarse woody debris (CWD) abundance and overall benthic habitat quality. Habitat augmentation is a common in-stream restoration method; however, little research has examined long-term (>10y) effects of such restorations. In 2003, CWD was experimentally added to 4 streams at Fort Benning Military Installation and compared to 3 unrestored streams to evaluate macroinvertebrate and habitat response to instream habitat augmentation. Effects 3y post-restoration were seasonal and variable among streams but, generally indicative of increased ecological integrity with seasonal increases in % Ephemeroptera, Trichoptera, and Plecoptera (EPT) and EPT density in restored streams. In 2017, we seasonally (summer, fall, winter) sampled macroinvertebrates and associated habitat in the same 7 streams to determine the long-term effects of restoration on stream condition. Macroinvertebrate sampling was performed in experimental reaches via four Hester-Dendy samplers (H-D) evenly spaced throughout the reach. H-D’s incubated for eight-week periods within each season. Benthic organic matter (BOM) was collected via substrate cores across five transects in the same reach when H-D samplers were being retrieved.
Results/Conclusions
Preliminary BOM analysis suggests similar seasonal patterns across streams as found 3y post restoration with streams having historically higher BOM persisting. Amount of BOM was not significantly different between restored and unrestored streams. However, overall BOM across all sites were higher in 2017 as compared to initial evaluations and restored sites are starting to diverge from the control sites with restored sites. Preliminary macroinvertebrate community analysis shows increases in %EPT and EPT density as compared to 3y post-restoration data with restored streams beginning to diverge from unrestored streams in EPT density with restored streams averaging 11.6 EPT/m2 while unrestored streams average 9.8 EPT/m2. Both restored and unrestored streams had increases in %EPT however, averaged 9.8% and 9.6% respectfully. The increase in BOM could be heavily influencing the %EPT and EPT densities in the restored streams. The divergence of restored streams from unrestored streams are hinting toward in-stream restoration being an effective practice but, requiring a longer settling period for beneficial effects to occur within dynamic sandy bottom systems of the Coastal Plains.