Treesearch

Snags (standing dead trees) are important components of forested habitats that contribute to ecological decay and recycling processes as well as providing habitat for many life forms. As such, snags are of special interest to land managers, but information on dynamics of snag populations is lacking. We modeled trends in snag populations in mixed-conifer and ponderosa pine (Pinus ponderosa) forests in northern Arizona using a Leslie matrix model developed by Raphael and Morrison (1987). Models were parameterized using data on snag abundance in five decay classes in 2002, transition rates of...

Interactions between grassland ecosystems and vertebrate herbivores are critical for a better understanding of ecosystem processes, but diverge widely in different ecosystems. In this study, we examined plant responses to simulated red deer (Cervus elaphus L.) grazing using clip-plot experiments in a subalpine grassland ecosystem of the Central European Alps. We measured aboveground net primary production (ANPP) and phosphorus (P) concentration of leaf tissue from plants of two vegetation types with different grazing history. The experimental plots were placed on a soil-P gradient and...

Large fires can result in a series of disasters for individuals and communities in the wildland-urban interface. They create significant disruptions to ongoing social processes, result in large financial losses, and lead to expensive restoration activities. By being aware of the impacts of wildland fire on local residents, fire managers can bring added value to them and help smooth agency-community tensions. This fact sheet discusses activities that can have serious impacts on communities and local residents during a wildland fire.

Independence and objectivity are key ingredients of scientific credibility, especially in research organizations that are part of a natural resource management agency like the Forest Service. Credibility, in turn, is essential to the utility of scientific information in socio-political processes. In order to develop this thesis further, a basic understanding of Forest Service organizational structure is important.

The concept of applying a "minimum requirements" analysis to decisions about administrative actions in wilderness in the United States has been around for a long time. It comes from Section 4(c) of the Wilderness Act of 1964, which states that "except as necessary to meet minimum requirements for the administration of the area for the purposes of this Act there shall be no temporary road, no use of motor vehicles, motorized equipment or motorboats, no landing of aircraft, no other form of mechanical transport, and no structure or installation within any such area." The concept interjects...

This paper presents a synthesis of experimental research testing effects of seasonal fire on community structure of plants, arthropods, and small mammals in shortgrass steppe. These groups of plants and animals share the same environment, and therefore, the species in the groups were predicted to respond in a similar way to changes in their environment resulting from fire. The experimental design was completely randomized with 3 treatments and at least 4 replicate 2-ha plots per treatment. Treatments were growing- and dormant-season fires and unburned. Response variables included: plant...

Winterfat (Krascheninnikovia lanata [Pursh] A. D. J. Meeuse & Smit; synonym: Ceratoides lanata [Pursh] J. T. Howell) is a desired shrub species and an integral component of salt desert shrublands in the Intermountain West. On the Snake River Birds of Prey National Conservation Area in southwestern Idaho, extensive loss of winterfat-dominated communities has been linked to altered fire regimes associated with cheatgrass (Bromus tectorum L.) invasions. Post-fire revegetation efforts are often hampered by the quick emergence of cheatgrass seedlings with autumn or spring moisture. We compare...

Bark beetles are known to have complex associations with a variety of microorganisms (Paine and others 1987; Ayres and others 2000; Six and Klepzig 2004). However, most of our knowledge involves fungi, particularly external species. In contrast, we know very little about their associations with bacterial gut symbionts (Bridges 1981). Similarly, work with wood colonizing insects such as termites reveals a diverse and functionally important community of gut bacteria (Hongoh and others 2005). Yet our knowledge of the gut microbiota of wood boring beetles is rudimentary. Our work is aimed at...

The bark beetles (Scolytinae) increase their potential to colonize their hosts by associating symbiotically with microorganisms, particularly fungi, which are carried on specialized structures called mycangium (Harrington 1993; Klepzig 2001; Paine and others 1997;Six 2003; Whitney 1982). Additionally, there is experimental evidence that some yeasts and bacteria from the alimentary canal of these insects might be involved in digestion and detoxification processes and pheromone production. The latter are compounds fundamental to the chemical communication of these insects (Borden 1982;Harring...

Quaking aspen (Populus tremuloides Michx.) a common species in North America, is a minor species in the Sierra Nevada of California. However, the limited coverage of aspen in this area appears to carry a disproportionate biodiversity load: numerous species are dependent on the unique components of aspen forests habitat. Land managers in the region believe the species is declining due to fire suppression policies of the past century. Recent research from other regions shows mixed results when assessing the extent of decline. This review focuses on the crossroads between human and natural...