Regional Botany Special Lecture
Novak, Steve .
The Sagebrush-steppe Sea: Beautiful and Imperiled Ecosystems of the Intermountain West .
As 19th century American pioneers traveled westward, especially along the Oregon Trail, they passed through a vast region consisting of the sagebrush steppe vegetation type. These pioneers referred to this region as the “Sagebrush Sea”. Sagebrush steppe ecosystems comprise approximately 43 million hectares of the Intermountain West in the United States. This region is described as having an arid or semi-arid continental climate that is characterized by long, cold winters and hot, dry summers. Sagebrush steppe vegetation has an overstory dominated by the shrub Artemisia tridentata (sagebrush) and other Artemisia spp. and understories composed of an array of perennial bunchgrasses (e.g., Achnatherum hymenoides, Festuca idahoensis, Hesperostipa comata, Poa secunda and Pseudoregneria spicata) and forbs such as Astragalus spp., Balsamorhiza spp., Castilleja spp., Lomatium spp., Lupinus spp. and Penstemon spp. The inter-plant matrix in these communities consists of an ecologically-important soil (microbiotic) crust that is composed of bacteria, fungi, lichens and mosses. In wetter years, when the productivity of sagebrush steppe communities increases, spring-time in this region is characterized by a multi-colored, profusion of flowering plants. Similar to many grass-dominated communities around the world, sagebrush steppe ecosystems are threatened by the drivers of global change. Since 1900, the effects of urbanization, agricultural development, livestock overgrazing, invasive grasses (chief among these is Bromus tectorum, cheatgrass) and changes in the fire regime have led to the degradation of approximately 90% of sagebrush steppe habitats. For instance, the fire-return interval within sagebrush steppe habitats prior to European settlement has been estimated to be every 60-100 years; whereas, because of the “cheatgrass fire-cycle”, this fire-return interval is currently estimated to be every 3-5 years. Thus, sagebrush steppe vegetation has been described as one of the most imperiled ecosystem in the United States. Management of sagebrush steppe vegetation has focused on reducing disturbances within these communities and on ecological restoration. How sagebrush steppe ecosystems respond to climate change is an unfolding story.
Log in to add this item to your schedule
1 - BOISE STATE UNIVERSITY, Department Of Biology, 1910 UNIVERSITY DR, BOISE, ID, 83725-1515, USA
Presentation Type: Special Presentation
Location: Summit/Boise Centre
Date: Tuesday, July 29th, 2014
Time: 11:00 AM
Candidate for Awards:None