Assessment of Streamside Management Zones for Conserving Benthic Macroinvertebrate Communities Following Timber Harvest in Eastern Kentucky Headwater Catchments

Joshua Adkins,Scott Grubbs,Jeffrey Stringer,Christopher Barton,Randall Kolka

doi:10.3390/w8060261

Abstract

Headwater streams generally comprise the majority of stream area in a watershed and can have a strong influence on downstream food webs. Our objective was to determine the effect of altering streamside management zone (SMZ) configurations on headwater aquatic insect communities. Timber harvests were implemented within six watersheds in eastern Kentucky. The SMZ configurations varied in width, canopy retention and best management practice (BMP) utilization at the watershed scale. Benthic macroinvertebrate samples collected one year before and four years after harvest indicated few differences among treatments, although post-treatment abundance was elevated in some of the treatment streams relative to the unharvested controls. Jaccard index values were similar across SMZ treatments after logging, indicating strong community overlap. These findings suggest that stream invertebrate communities did respond to the timber harvest, though not negatively. Results also suggest that SMZ criteria for aquatic habitats in steeply sloping topography, including at least 50 percent canopy retention and widths of at least 16.8 m, appear to be adequate for protecting benthic macroinvertebrate communities from logging impacts.

Highlights

Headwater streams represent the majority of stream area in a watershed and strongly influence downstream conditions, including water levels, nutrients, prey subsidies, and both coarse and fine woody debris [1,2,3]
In 2004, the C streams were most similar in community composition to treatment 1 (T1) in both channel types, We found no statistical differences in Simpson’s diversity index among streamside management zone (SMZ) treatments in the and were least similar to treatment 2 (T2) (Table 4)
DiscussionWhile many SMZ studies, including ours, provide information on initial response one or two years after harvest, this study examined the longer-term response four years after the harvest

Summary

Introduction

Headwater streams represent the majority of stream area in a watershed and strongly influence downstream conditions, including water levels, nutrients, prey subsidies, and both coarse and fine woody debris [1,2,3]. Because of their smaller size, headwater stream watersheds are readily influenced by localized disturbances [4,5]. Riparian zones are areas of reciprocal influence between aquatic and terrestrial components of the landscape These interfaces play a key role in maintaining stream temperatures, nutrients, and food resources within aquatic systems [6,7,8,9,10]. In temperate forests, headwater streams are often deeply shaded by surrounding

Objectives

Results

Conclusion