Open Access. Powered by Scholars. Published by Universities.®
Ecology and Evolutionary Biology Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Ecology and Evolutionary Biology
Avian Community Responses To Bison Grazing In North American Intermountain Grasslands, Danielle A. Fagre
Avian Community Responses To Bison Grazing In North American Intermountain Grasslands, Danielle A. Fagre
Graduate Student Theses, Dissertations, & Professional Papers
Grassland and shrubland songbird species are a guild of conservation concern in North America. Many of these species have experienced severe population declines, due to habitat loss and land use change. This makes the conservation and management of remaining habitat of crucial importance for this guild. Grazing by large herbivores is an ecosystem process in grassland systems, and in North America, one of the major historic grazers was the Plains bison (Bison bison). Bison are considered ecosystem engineers, because they modify habitat to be more or less suitable for other species, such as grassland and shrubland songbirds. Bison …
Bottom-Up And Top-Down Controls On Food Webs In Headwater Streams, Miriam O. Bayer
Bottom-Up And Top-Down Controls On Food Webs In Headwater Streams, Miriam O. Bayer
Graduate Student Theses, Dissertations, & Professional Papers
Headwater streams account for 70% of stream channel length in the USA and are important as hotspots of nutrient uptake and native biodiversity. Biofilm, the mixed auto- and heterotrophic microbial community covering stream substrates, is where the majority of nutrient processing occurs, and forms the base of stream food webs, particularly in heavily shaded, oligotrophic streams. Both bottom-up (e.g., nutrients, light) and top-down (i.e., consumption) processes are known to affect periphyton, the autotrophic component of biofilm, but little is known about what controls the biofilm community as a whole. Top-down effects are common in streams, where fish are often the …