Treesearch

Roadless areas of southeastern Arizona managed by the Bureau of Land Management are becoming rare. Fragmentation by roads and development, all-terrain vehicle use, erosion, and altered hydrology are a few of the causes of loss and degradation of roadless areas. The history of BLM and publicly identified roadless areas includes the passage of the Wilderness Act of 1964, the Federal Lands Policy and Management Act of 1976, the development and passage of the Arizona Wilderness Act of 1984, the Arizona Desert Wilderness Act of 1990, the efforts of the Arizona Wilderness Coalition in the 1980s,...

Ecosystems are bisected by international borders along the United States-Mexican border; infrastructure and the heightened security activities bisect the north-south cores, corridors, and buffers essential to preservation of ecosystems. The Southwest Consortium for Environmental Research and Policy (SCERP) and its partners convened an annual policy conference, Border Institute VI, where participants developed 10 recommendations to affect change in current transboundary ecosystem management policies throughout the United States-Mexican border region. Recommendations addressed institutionaliz...

The Arizona Game and Fish Department (Department) has developed a Safe Harbor Agreement (SHA) for four native fishes in Arizona. The SHA will allow Gila and Yaqui topminnow (Poeciliopsis occidentalis and P. sonoriensis) and desert and Quitobaquito pupfish (Cyprinodon macularius and C. eremus) to be released onto non-Federal lands while safeguarding landowner options for future property use. The SHA will assist recovery of these species by: creating replicate populations; creating partnerships between State, Federal, and other groups; minimizing stocking of mosquitofish and other nonindigeno...

The last wild Tarahumara frog (Rana tarahumarae) in Arizona was found dead in Big Casa Blanca Canyon, Santa Rita Mountains, in May 1983. However, the species is still well represented in the majority of its range in the northern Sierra Madre Occidental and adjacent Sky Islands of Sonora and Chihuahua. Plans to re-establish R. tarahumarae in Arizona were initiated in 1992 and have been coordinated by the Tarahumara Frog Conservation Team. Initial experimental releases of Tarahumara frogs to Big Casa Blanca Canyon, Santa Cruz County, Arizona, are tentatively scheduled for June 2004. If...

The increase in severe wildfires in recent years is due in part to an abundance of fuels in forests. In an effort to protect values at risk, and decrease the severity of wildfires, forest managers have embarked on a major program of fuel reduction. Past research has shown that such fuel reduction may have minimal impact at a hillslope scale, but when numerous hillsides are disturbed within a watershed over a number of years, the cumulative effect of such disturbances may be unacceptable. In addition, road networks are necessary to support fuel management activities by providing access for...

The U.S. Department of Agriculture Forest Service is considering alternative methods of erosion control when constructing roads, decommissioning roads, protecting lands burned by wildland fires, and reclaiming lands disturbed by other activities. This article is the second in a series of tech tips that discuss the use of wood shreddings for erosion control. The first tech tip, Shredding Small Trees To Create Mulch for Erosion Control (0471–2335–MTDC, http://www. fs.fed.us/eng/t-d.php) discussed the benefits of using wood shreddings rather than straw for erosion control, described three...

Little information is available regarding red wood ant (RWA; Formica rufa group) impacts on soil carbon (C) and nitrogen (N) cycling in forest ecosystems. We found that RWA mound density (number per ha) was linked to forest tree species composition, slope aspect, and canopy closure. The size of RWA mounds was positively correlated with successional age of the stands. C and N concentrations of mound material were significantly higher than in the forest floor, while C:N ratios were not. RWA mound C and N pools were found to be significantly lower (≤990 kg C/ha and ≤21 kg N/ha) than in the...

The lower San Pedro River, downstream from Benson, is a nearly unfragmented habitat containing perennial flow reaches that support riparian vegetation that serve as “stepping stones” for migratory species. The Nature Conservancy has purchased farm properties and retired agricultural pumping along the lower river, based largely on results from hydrologic analyses indicating that increased water availability for riparian vegetation will result from retiring agricultural pumping at key locations. A long-term commitment to hydrologic and ecological monitoring provides data that the Conservancy...

Riparian areas in the Madrean Archipelago have historically provided water necessary for people, livestock, and agricultural crops. European settlers were attracted to these areas in the 1880s, where they enjoyed shade and forage for themselves and their livestock and existed on the readily available wildlife and fish. Trees growing along stream banks were harvested for fuel, poles, and building materials. Demands for water dominated management of riparian corridors as human populations increased after World War II. Many of these fragile ecosystems were altered by attempts to salvage...

Major concerns after wildfires are the increased erosion and flooding potential due to loss of the protective forest floor layer, loss of water storage, and the creation of water repellent soil conditions. Treatments to mitigate postfire erosion and runoff are commonly applied on highly erodible areas; however the effectiveness of these treatments has had limited scientific evaluation. In recent years postfire hillslope treatment effectiveness has been evaluated by using sediment fences and small catchments to directly measure sediment yields from burned hillslopes and relate those results...