Treesearch

The influences of both predator density and elapsed time between initial infestation and introduction of predators were determined for suppression of bruchids infesting stored grain legumes by Xylocoris flavipes (Reuter) (Hemiptera: Anthocoridae). Predator density treatments consisted of zero, one, two, three, or five male:female pairs of adult X. flavipes added to experimental arenas 0, 24, or 120 h after bruchid introduction. Suppression of Acanthoscelides obtectus approached eradication with all predator treatments. For all other bruchid species evaluated (Callosobruchus analis, C....

Qualitative risk assessment methodologies were used to assess the risk of establishment and consequent impacts on native minnows and species of concern (SOC) associated with the intentional or unintentional introduction of the mosquito biological control agent, Gambusia affinis, to various Montana watersheds. Gambusia affinis introductions for mosquito control have been made throughout the world; some introductions have resulted in deleterious effects on native species. We used average January water temperatures, the presence of dams, and the presence of native minnows and SOC to define...

A close relative of spotted knapweed in the Asteraceae taxonomic family, diffuse knapweed is typically biennial, reproducing exclusively by seed. It forms a rosette with a central crown and tap root in the juvenile stage and a single upright stem one to three feet (0.3 to 0.9 m) tall with numerous spreading branches at maturity. White (occasionally purple) flowers are borne in heads with spiny bracts (see Figure 1). It is generally found on more arid sites than spotted knapweed. Native to the Mediterranean region, diffuse knapweed was first recorded in Montana from Mineral County in 1951...

The ecological condition and trend of the United States' 3,902,000 of Drylands and the extent to which human management actions contribute to degradation are unknown at the national spatial scale. (Washington-Allen et al. 2006). Our research seeks to develop procedures for determining the impact or ecological footprint of livestock grazing on the productive capacity of Drylands at the national spatial scale.

The Sustainable Rangelands Roundtable (SRR) recognizes the unique contributions rangeland resources make to the nation's wellbeing. To communicate the importance of these commodity and amenity values, SRR participants developed this primer on rangeland ecosystem goods and services. It summarizes the history of the nation's relationship with and reliance upon rangeland resources, as well as the evolution of SRR's contribution to current concepts about advancing rangeland stewardship and conservation.

A recent series of severe fire seasons in the United States has contributed to sharply rising wildfire suppression costs. These increasing costs have caught the attention of policy makers, but so far the responses have not focused clearly on the incentive structures that allow or encourage rising costs (National Academy of Public Administration 2002). We analyze the problem of rising suppression costs by examining the incentive structures faced by fire managers. Specifically, we examine the influence of wildfire suppression funding mechanisms on managers' behavior. The rationale for this...

The wildland fire management organization of the United States Forest Service (USFS) operates under policy and budget legacies that began nearly 100 years ago and a forest fuel situation that is all too current. The confluence of these three factors contributes to increased burning and fire fighting costs for the agency, and increased concern from both the U.S. Congress and the public. Historically, the 10-year moving average of suppression expenditures has been used in USFS annual budget requests to Congress. But in a time when fire activity and costs are steadily rising, the 10-year...

This study, conducted among ranchers on the Santa Fe and Carson National Forests in the Southwestern United States, examines the role of ranching in maintaining traditional heritage and cultural continuity. The mainly Hispanic ranching families of northern New Mexico first came into the region in 1598 with Spanish colonization. Many of the villages received community land grants from the King of Spain and later from the Mexican government. After US acquisition in 1848, many communities lost communal range and woodlands from their land grants. Much of the lost grant land eventually came...

Fleas are among the most common arthropod vectors of many of rodent borne diseases like plague (Yersina pestis). Human outbreaks of plague are commonly associated with the presence of peridomestic rodent species (Perry and Featherston, 1997) . Anthropogenic disturbance with respect to both habitat use and climate change can affect disease emergence and prevalence through its impact on hosts and host-parasite (vector) ecology (Daszak et al., 2001) . Vector-borne disease transmission is often related to species diversity (Keesing et al., 2006). In addition, flea abundance and host spectrum...

The attenuation of radiation transfer from wildland flames to fuel by environmental water vapor is investigated. Emission is tracked from points on an idealized flame to locations along the fuel bed while accounting for absorption by environmental water vapor in the intervening medium. The Spectral Line Weighted-sum-of-gray-gases approach was employed for treating the spectral nature of the radiation. The flame and fuel bed for the simulations are modeled two-dimensionally with the flame being one-tenth as long as the fuel bed. Flame heights of 1 and 10 m were explored, and both vertical...