Treesearch

DNA sequence data were collected and screened for single nucleotide polymorphisms (SNPs) in westslope cutthroat trout (Oncorhynchus clarki lewisi) and also for substitutions that could be used to genetically discriminate rainbow trout (O. mykiss) and cutthroat trout, as well as several cutthroat trout subspecies. In total, 260 expressed sequence tag-derived loci were sequenced and allelic discrimination genotyping assays developed from 217 of the variable sites. Another 50 putative SNPs in westslope cutthroat trout were identified by restriction-site-associated DNA sequencing, and seven of...

Competition and resource availability influence invasions into native perennial grasslands by nonnative annual grasses such as Bromus tectorum. In two greenhouse experiments we examined the influence of competition, water availability, and elevated nitrogen (N) and phosphorus (P) availability on growth and reproduction of the invasive annual grass B. tectorum and two native perennial grasses (Elymus elymoides, Pascopyrum smithii). Bromus tectorum aboveground biomass and seed production were significantly reduced when grown with one or more established native perennial grasses. Conversely,...

We tested antlers of Coues white-tailed (Odocoileus virginianus couesi) and mule deer (O. hemionus) in various stages of natural decomposition to determine the degree of weathering that cast antlers could endure and still yield usable DNA. Based on physical characteristics, we partitioned antlers into 7 weathering categories ranging from freshly cast (class 1) to having been exposed to weathering for 8 years (class 7). Most antlers that had weathered 1-7 years yielded amplifiable DNA, whereas antlers weathered for 8 years failed to yield replicable DNA. This study confirms that antlers...

Using forests to sequester carbon in response to anthropogenically induced climate change is being considered across the globe. A recent U.S. executive order mandated that all federal agencies account for sequestration and emissions of greenhouse gases, highlighting the importance of understanding how forest carbon stocks are influenced by wildfire. This paper reports the effects of the most common forest fuel reduction treatments on carbon pools composed of live and dead biomass as well as potential wildfire emissions from six different sites in four western U.S. states. Additionally, we...

Mountain lions (Puma concolor) are often difficult to monitor because of their low capture probabilities, extensive movements, and large territories. Methods for estimating the abundance of this species are needed to assess population status, determine harvest levels, evaluate the impacts of management actions on populations, and derive conservation and management strategies. Traditional mark-recapture methods do not explicitly account for differences in individual capture probabilities due to the spatial distribution of individuals in relation to survey effort (or trap locations)....

The Forest and Rangeland Renewable Resources Planning Act (RPA) of 1974 requires periodic assessments of the status and trends in the Nation's renewable natural resources including fish and other aquatic species and their habitats. Data from a number of sources are used to document trends in habitat quality, populations, resource use, and patterns of imperilment among aquatic fauna. Freshwater habitat quality varied widely across the United States. Nationwide, more than half of monitored lakes were ranked in good condition, but the percentage ranged from a high of 91 percent in the upper...

Wetlands and riparian areas are unique landscape elements that perform a disproportionate role in landscape functioning relative to their aerial extent on the landscape. The purpose of this guide is to provide a general foundation for the reader in several interrelated disciplines for the purpose of enabling him/her to characterize and quantify the water needs of riparian and wetland vegetation. Topics discussed are wetland and riparian classification, characteristics and ecology, surface and groundwater hydrology, plant physiology and population and community ecology, and techniques for...

Because the rate of anthropogenic climate change exceeds the adaptive capacity of many animal and plant species, the scientific community anticipates negative consequences for ecosystems. Changes in climate have expanded, contracted, or shifted the climate niches of many species, often resulting in shifting geographic ranges. In the Great Basin, for example, projected increases in temperature could decrease ability of sagebrush to compete with warm-desert shrubs, leading to a shift in community composition.

Within the continental United States, average annual temperature increased during the Twentieth Century by approximately 0.65 ºC. The most extreme warming occurred throughout the northern and western United States (IPCC 2007a; Williams and others 2010). Disturbances such as fire, drought, grazing, urbanization, and energy development are predicted to have a heightened impact on the western United States under a changing climate. For example, extreme drought conditions accompanied by rising temperatures characterized the American Southwest during the past decade (Floyd and others 2009).

Invasive species present one of the greatest threats to the health and sustainability of ecosystems worldwide. Invasive plants, animals, and diseases are known to have significant negative effects on biological diversity and the ecological structure and functions of native ecosystems. Moreover, the economic cost imposed by invasive species is enormous—the damage inflicted to natural resources and costs of control measures is an estimated $137 billion each year in the United States. Climate change can fundamentally alter the behavior, spread, and harm caused by invasive species and the...