Treesearch

The threat posed by exotic organisms to native systems has led to extensive research on exotic invaders, yet management of invasives has progressed relatively slowly. This is partly due to poor understanding of how exotic species management influences native organisms. To address this shortfall, we experimentally evaluated the efficacy of an invasives management tool for restoring native deer mouse (Peromyscus maniculatus) populations elevated by exotic species. The exotic insects, Urophora spp., were introduced in North America for biological control of the Eurasian invader, spotted...

La posibilidad de perdidas humanas y de propiedad en Nuevo Mexico debido a un incendio forestal ha ido incrementando. Para responder a este peligro, entidades locales, estatales, federales, particulares y sin fines de lucro se han unido para crear Como Reducir la Amenaza de Incendios Forestales, un programa dirigido a los propietarios de casas. Este no es un programa de prevencion de incendios. Su objetivo es ensenarles a las personas como vivir mas seguros con la amenaza de un incendio forestal. En muchas zonas de esta region, no se trata de "si"va a haber un incendio, mas bien es...

Precise, unbiased estimates of population size are an essential tool for fisheries management. For a wide variety of salmonid fishes, redd counts from a sample of reaches are commonly used to monitor annual trends in abundance. Using a 9-year time series of georeferenced censuses of Chinook salmon (Oncorhynchus tshawytscha) redds from central Idaho, USA, we evaluated a wide range of common sampling strategies for estimating the total abundance of redds. We evaluated two sampling-unit sizes (200 and 1000 m reaches), three sample proportions (0.05, 0.10, and 0.29), and six sampling strategies...

We used daytime and nighttime underwater observation to assess microhabitat use by bull trout Salvelinus confluentus (N = 213) in streams of the intermountain western USA during the summers of 2001 and 2002. We recorded fish focal points and measured a set of habitat characteristics as well as habitat availability via line transects. Bull trout were benthic and solitary; most (88%) were observed at night. We developed a conditional logistic regression model to account for the effect of fish movement in response to snorkeling, and we fitted 18 candidate models to evaluate the relative...

Locations with natural characteristics, such as forests, are thought to be attractive residential locations. This proposition is tested in the Southwest United States, composed of Arizona and New Mexico. This paper presents a conditional logit model of location choice estimated with household observations from the U.S. Census, geographic information system (GIS) data, and county-level data. Results suggest that forest area, both in one's own location and nearby, increases the probability of choosing a location. But significant heterogeneity in location choices exists; an income effect and...

In the past two decades, there has been a significant increase in the number of acres burned by wildland fires and in the amount of money being spent to suppress these fires (Calkin et al. 2005a). With expenditures on suppression alone climbing to more than a billion dollars in four of the past seven years (2000-2006), the federal land management agencies are coming under ever increasing pressure by Congress and government oversight agencies to manage fire in a cost efficient manner. Economic analysis can benefit all fire-related programs and activities, and ignoring economic analysis in...

The reliability of monitoring visual obstruction and estimating standing herbage with a modified Robel pole was examined for high-elevation meadows in sedimentary soils on the Bighorn National Forest, Wyoming. Our objectives were to (1) test a modified pole graduated with 1.27-cm (0.5-inch) bands for estimating standing herbage based on linear regression of visual obstruction readings (VORs) on standing herbage, (2) validate the derived regression, (3) provide sample size estimates, and (4) develop guidelines for monitoring mountain grasslands.

Conservation agencies and organizations are generally reluctant to encourage the use of invasive plant species in conservation programs. Harsh lessons learned in the past have resulted in tougher screening protocols for nonin digenous species introductions and removal of many nonindigenous invaders from planting programs worldwide. Although the focus of screening and risk assessment programs has traditionally been on nonindigenous species, we present an example of a rapidly expanding native tree, eastern redcedar (Juniperus virginiana), widely used in planting programs throughout the...

Small-mammal seed predation is an important force structuring native-plant communities that may also influence exotic-plant invasions. In the intermountain West, deer mice (Peromyscus maniculatus) are prominent predators of native-plant seeds, but they avoid consuming seeds of certain widespread invasives like spotted knapweed (Centaurea maculosa). These mice also consume the biological-control insects Urophora spp. introduced to control C. maculosa, and this food resource substantially increases deer mouse populations. Thus, mice may play an important role in the invasion and management...

There has been a recent trend in genetic studies of wild populations where researchers have changed their sampling schemes from sampling pre-defined populations to sampling individuals uniformly across landscapes. This reflects the fact that many species under study are continuously distributed rather than clumped into obvious "populations". Once individual samples are collected, many landscape genetic studies use clustering algorithms and multilocus genetic data to group samples into subpopulations. After clusters are derived, landscape features that may be acting as barriers are examined...