Within-community vegetation structure in the conifer woodlands of the Siskiyou Mountains, Oregon

✍ Scribed by Wilson, Mark V.

• Book ID: 104621690
• Publisher: Springer-Verlag
• Year: 1988
• Tongue: English
• Weight: 960 KB
• Volume: 78
• Category: Article
• ISSN: 1573-5052
• DOI: 10.1007/bf00045640

✦ Synopsis

The conifer woodlands found on serpentine-derived soils in southwest Oregon, USA, are characterized by a dense but discontinuous shrub stratum and a species-rich herbaceous stratum. Quantitative analysis of shrub and herb distributions within 10 sites showed that small-scale patterns within the conifer woodland sites are as important as landscape-scale patterns in community organization. Gradient analysis was used to describe the distribution of herbaceous species with respect to gradients of shrub influence (shading, decreased soil temperature, increased soil moisture, increased litter depth) within sites and topographic moisture among sites. Regression analysis of the resulting species distributions and calculations of alpha and beta diversity showed that (a) the shrub-influence microgradient significantly affected distributions for 15 out of 20 major herbaceous species, and the topographic-moisture gradient influenced 13 out of the 20 species, (b) species richness was higher under intermediate conditions along both gradients, and (c) beta diversity within communities was 2.5 to 3.8 times the beta diversity of the site-to-site topographic-moisture gradient.