Effects of experimental forest removal on macroinvertebrate production and functional structure in tallgrass prairie streams

Abstract

Encroachment by woody vegetation is a major threat to tallgrass prairie streams, and converts them from open-to closed-canopy systems. This change presumably shifts the relative importance of basal resources from autochthonous to allochthonous and may alter functional feeding group composition and production of consumers. Riparian trees were removed from 2 headwater stream reaches on the Konza Prairie Biological Station to examine effects of forest encroachment and removal. Removal reaches were compared to reaches with naturally open and closed canopies before and after manipulation. Benthic organic matter and macroinvertebrates were sampled monthly for 1 y before (year 1) and after (year 2) riparian forest removal. Total secondary production in removal reaches ranged from 8.9 to 10.2 g ash-free dry mass (AFDM) m −2 y −1 in year 1, and increased significantly to 13.4 to 14.5 g AFDM m −2 y −1 in year 2. Scraper production in removal reaches was 2.8 to 3.9 g AFDM m −2 y −1 in year 1, and increased significantly to 6.0 to 8.7 g AFDM m −2 y −1 in year 2. Shredders did not respond negatively to the removal, but scrapers dominated production (45-60% of total) in open and removal reaches after manipulation. Total production in naturally open reaches was 7.6 to 12.6 g AFDM m −2 y −1 in year 1 and decreased to 6.5 to 9.8 g AFDM m −2 y −1 in year 2. Riparian forest removal altered macroinvertebrate production and functional structure, but higher production in removal reaches than in open reaches after manipulation suggested that natural conditions were not restored 1 y after removal. However, ordinations indicated communities in open and removal reaches became more similar after manipulation. Forest encroachment alters prairie stream structure and function, and riparian forest removal may be an effective restoration and management practice for remaining prairie streams.Prairie habitats once covered ∼162 million ha of North America, but most were significantly altered for agriculture, resulting in <5% of intact prairie remaining (Samson and Knopf 1994). Reduced native ungulate grazing and decreases in fire frequency and intensity in the last century have resulted in the encroachment of native woody species on the few remaining prairie remnants, particularly along riparian corridors. In some regions, fire suppression has resulted in complete conversion to closed-canopy forest in as little as 35 y (Hoch and Briggs 1999). These changes in riparian vegetation ultimately result in a shift from open-to closed-canopy conditions. Riparian vegetation strongly influences the chemical and physical attributes of streams, ultimately affecting ecosystem structure and function (Vannote et al. 1980, Gregory et al. 1991. Historically, because of the frequency of wildfires, ungulate grazing, and hydrological patterns, headwater tallgrass prairie streams were bordered by relatively short riparian prairie vegetation (e.g., grasses, forbs, and shrubs) and characterized as open-canopy systems Dodds 1998, Dodds et al. 2004). These conditions res...

A synthesis of land use impacts on stream biodiversity across metrics and scales

“…(2015), Song et al. (2009), Teresa and Casatti (2017), Vandermyde and Whiles (2015), and Yule et al. (2015) (Appendix : Table S1; part of the data is available at Zenodo: see Open Research ).…”

Influence of fishes on macroinvertebrate communities and insect emergence production in intermittent stream refuges

“…Invertebrate production can be relatively high and the communities at KPBS are well-studied, primarily in Kings Creek (see Gray & Johnson This article is protected by copyright. All rights reserved Author Manuscript 1988, Stagliano & Whiles 2002, Whiting et al 2011, and Vandermyde & Whiles 2015.…”

Trajectories and state changes of a grassland stream and riparian zone after a decade of woody vegetation removal

“…The riparian zone mediates water flow into stream channels, where moisture may select for woody plant growth due to increased water availability relative to other upslope terrestrial landscapes (Rood et al, 2003). Riparian vegetation can exert controls on stream channel morphology (Sweeney et al, 2004), strongly affect water quality (Banner et al, 2009; Dodds & Oakes, 2006; Dosskey et al, 2010; Grudzinski et al, 2016), and alter energy flow and food webs in streams (Baxter et al, 2005; Vandermyde & Whiles, 2015). Deforestation in temperate forested watersheds can strongly increase movement of nutrients and sediments to streams without intact riparian zones (Hobbie & Likens, 1973).…”