The effects of riparian tree harvest intensity and woody debris addition on biotic and abiotic stream characteristics

Abstract

The effect of riparian tree harvest intensity on biotic and abiotic stream characteristics Jered Michael Studinski Forested headwater streams rely on riparian zones for many critical products and services. Riparian areas shade streams, stabilize stream banks, filter sediment, and provide allochthonous materials like leaves, large woody debris (LWD), and terrestrial invertebrates (TI's). Logging can affect the products and services of riparian zones. Best management practices (BMP's) have been developed to minimize the impacts of riparian timber harvest on streams. The main component of these guidelines is the establishment of a road-free riparian buffer called a streamside management zone (SMZ). The West Virginia Division of Forestry's BMP's require a SMZ that is at least 30 m wide for perennial and intermittent streams. There is no harvest limit within the SMZ, although heavy equipment cannot be operated within the area. This study quantified the effect of LWD additions and riparian tree harvest intensity at 50% and 90% basal area harvest (BAH) on various biotic and abiotic characteristics of eight Appalachian headwater streams. Stream temperatures and pool formation rates were affected by the treatments. Stream temperature increased as canopy cover decreased. During the warmest days in summer, water temperature within 90% BAH sections reached levels that could be stressful or lethal to salmonids. The combination of 50% BAH sections and unharvested sections appeared to maintain natural thermal regimes. Neither the BAH nor the LWD treatments had an effect on stream turbidity or sedimentation rates within the experimental sections. The haphazard LWD additions resulted in no net increase in pool area. However, a greater number of pools were created and destroyed in the LWD addition sections. LWD additions also increased habitat complexity and most likely decreased the long-term LWD deficit that often occurs following logging operations. Periphyton biomass increased with decreasing canopy coverage. Temperature and alkalinity did not significantly affect periphyton biomass, although the temperature gradient was small. Trends of increasing periphyton biomass were observed with canopy reductions as small as 6.4%. TI inputs, a critical food source for trout, were affected by the BAH treatments. TI input biomass was significantly higher in the 90% BAH sections. TI input composition varied significantly between years (natural variation) and between the reference and 90% BAH sections. At greater harvest intensities, increases of Acrididae and Tettigoniidae (Orthoptera), wood-associated coleopterans, Formicidae (ants) and pollinating hymenopterans were observed. Aquatic invertebrates (AI's) were, for the most part, unaffected by the treatments. AI abundance, richness, and biomass were not affected by the BAH or LWD treatments. AI abundance and biomass was significantly affected by natural annual variation. AI communities were not affected by the treatments, although a significant and more-direct relationship was observed be...

Importance of terrestrial subsidies for native brook trout in Appalachian intermittent streams

“…Low terrestrial biomass may characterise streams in the Appalachian Mountains because other studies in this region have also found low terrestrial biomass (e.g. 17.3 mg m À2 day À1 seeRomaniszyn, Hutchens & Wallace, 2007;Studinski, 2010); however, values from our study in the Ridge and Valley region of Virginia are a magnitude lower than similar-© 2013 John Wiley & Sons Ltd, Freshwater Biology, 58, 2423-2438…”

“…Low terrestrial biomass may characterise streams in the Appalachian Mountains because other studies in this region have also found low terrestrial biomass (e.g. 17.3 mg m −2 day −1 see Romaniszyn, Hutchens & Wallace, ; Studinski, ); however, values from our study in the Ridge and Valley region of Virginia are a magnitude lower than similar‐sized streams located in the Piedmont region of Virginia possibly due to the large differences in geology and vegetation between these two regions (Cloe & Garman, ). Additionally, intermittency can play a role in this regional variation because intermittent streams may have different vegetation or provide unique habitat or microclimate conditions that lead to low terrestrial biomass (Steward et al ., ; Katz, Denslow & Stromberg, ).…”

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Brook trout response to canopy and large woody debris manipulations in Appalachian streams

“…Invertebrates were placed into bottles and preserved in 80% ethanol. For more detailed analysis of this study please seeStudinski 2010.…”