Treesearch

This electronic newsletter (Invasive Species Science Update) is published by the Rocky Mountain Research Station (RMRS) Cross-Program, Interdisciplinary Project team on Invasive Species. This newsletter will be published 3 times per year and is intended to enhance communication among RMRS scientists, wildland managers, other partners, stakeholders, and customers about predicting, detecting, and monitoring invasive species in forest, rangeland, and aquatic ecosystems. Contributions for the newsletter are welcome from everyone involved in the ecology and management of any invasive species....

Mee-Sook and I received several favorable comments regarding the first issue of the Invasive Species Science Update. In true Government form, the newsletter is now often referenced by the acronym ISSU. So, this is the second issue of ISSU.

Pinyon-juniper (Pinus monophylla Torr. & Frém.? Juniperus osteosperma Torr.) encroachment into sagebrush grasslands is a continuing problem in the Western United States. Prescribed burning has been suggested to slow woodland encroachment. We examined surface soil microbial community structure using Phospholipid Fatty Acid (PLFA) analyses to determine differences between burned and unburned woodlands at two microsites. Tree canopy interspace microsites had a greater total PLFA and percentage Eukaryotes. Conversely, under tree canopy microsites had a greater percentage of fermicutes,...

Extensive drought during the years of 2002, 2003, and 2004 removed most plant cover. On May 10, 2004, a cold front to the north resulted in weather stations in the area recording 600+ miles of wind travel (comparable to 60 mile hour winds for 10 hours). The effect of these two climatic events was to bury the Mile Square subdivision in wind-blown sand. Sand filled homes, garages, barrow pits, and closed roads. Even though the drought decimated perennial vegetation, including killing most of the shrubs in the area, the only areas that did not blow were the areas occupied by dead shrubs.

In recent decades Northern Nevada has experienced a dramatic increase in cheatgrass (Bromus tectorum). As a result, wildfire frequency and size has increased. The objective of this project was to examine natural vegetation recovery and trend following 1985 wildfires. Density and cover measurements determined a high but fluctuating occurrence of cheatgrass and minimal change of perennial grass and shrubs. Loamy 8-10 ecological sites have a greater potential for consistently producing more cheatgrass plants and cover than loamy 5-8 and droughty loam sites.

The monitoring of Geyer willow was based on the following management objective: Browsing will prevent fewer than 50 percent of Geyer willow shrubs from growing taller than 3 m. Three questions were addressed: (1) Is browsing a potential factor? (2) If so, can young plants grow taller than 3 meters? (3) If not, is browsing the dominant factor? All shrubs were intensely browsed. With a post-browsing growth rate of 5.0 cm per yr, no shrub could grow 3 m tall. Analyses of stem growth rate excluded dominant roles for climate and plant vigor. Browsing and stem age were the dominant factors that...

A small prescribed fire near the mouth of Trout Creek in Strawberry Valley, Wasatch County, Utah, on the Uinta National Forest provided an opportunity to compare production and vascular plant composition in unburned and burned areas. At four years post burn, production of herbaceous plants was about four times greater in the burned area than in the unburned area. Most plants found in the unburned area were found in the burned area at four years post burn.

Photography and notes on file at the Supervisors Office, Ashley National Forest make it possible to date many fires in mountain big sagebrush (Artemisia tridentata ssp. vaseyana) communities on this National Forest. Crown cover of mountain big sagebrush and other shrubs was measured in repeat visits to many burned sites. Burned areas studied varied in age from 1 year to 42 years. Crown cover measurements in these burns demonstrate high capability of mountain big sagebrush to return to burned sites. Crown cover of mountain big sagebrush was highly variable in post burn environments. After...

Very large scale aerial (VLSA) imagery is an efficient tool for monitoring bare ground and cover on extensive rangelands. This study was conducted to determine whether VLSA images could be used to detect differences in antelope bitterbrush (Purshia tridentata Pursh DC) cover and density among similar ecological sites with varying postfire recovery periods. In 2005, VLSA images were acquired at 253 points from high bitterbrush potential ecological sites at the USDA-ARS, U.S. Sheep Experiment Station, Dubois, Idaho. For each image, fire history was classified and bitterbrush density and...

We sampled unchained and chained areas in 2004 and 2005 on the Henry Mountains that had been aerially seeded after the Bulldog Fire of 2003. Establishment of seeded grasses was high on unchained and chained areas although chaining increased seeded grass establishment on some sites. Western yarrow established well on unchained areas. Initially, high seedling emergence in 2004, followed by high precipitation in late winter 2005, produced 15 to 25 percent total seeded plant cover on both unchained and chained areas by summer of 2005. Aerial seeding at lower elevations and with less precipitati...