Headwater riparian forest-floor invertebrate communities associated with alternative forest management practices.
Authors:
Rykken, J.J. Moldenke, A.R. Olson, D.H. USDA, FS
Source:
Ecological applications : a publication of the Ecological Society of America. 2007 June, v. 17, no. 4, p. 1168-1183.
NALT Subjects:
riparian forests forest litter forest ecology soil invertebrates community ecology conservation areas microclimate forest management ecotones streams microhabitats species diversity biodiversity Oregon
Other Subjects:
riparian reserves headwater streams community composition
Issue Date:
Jun-2007
Abstract:
Headwater streams and their riparian zones are a common, yet poorly understood, component of Pacific Northwest, USA, landscapes. We describe the ecological importance of headwater stream riparian zones as habitat for forest-floor invertebrate communities and assess how alternative management strategies for riparian zones may impact these communities. We compared community composition of forest-floor invertebrates at increasing distances along trans-riparian (stream edge to upslope) transects in mature forests, clearcuts, and riparian buffers of 30-m width with upslope clearcuts. Invertebrates were collected using pitfall traps in five replicate blocks of three treatments each in the Willamette National Forest, Oregon, USA. We measured microclimate and microhabitat variables at pitfall locations. Despite strong elevation and block effects on community composition, community analyses revealed a distinct “riparian” invertebrate community within 1 m of the stream edge in mature forest treatments, which was strongly related to cool, humid microclimate conditions. Invertebrate community composition in buffer treatments was far more similar to that of mature forests than to clearcuts; a pattern mirrored by microclimate. These results suggest that, within our study sites, forest-floor invertebrate distributions are strongly associated with microclimate and that riparian buffers of 30-m width do provide habitat for many riparian and forest species. Riparian reserves may serve as effective forest refugia and/or dispersal corridors for invertebrates and other taxa, and their incorporation into watershed management plans likely will contribute to meeting persistence and connectivity objectives.
