Treesearch

Coues white-tallied deer (Odocoileus virginianus couesi) and desert cottontail (Sylvilagus auduboni), also known as Audubon cottontail, are inhabits of oak savannas in the Southwestern Borderlands region. Food, cover, and scattered water for these two species are found in this comparatively open ecosystem. The results of a study on the presence (occurrence) of Coues white-tailed deer and desert cottontail in unburned the oak savannas of the Southwestern Borderlands Region are presented in this paper. Effects of cool-season and warm-season prescribed burning and a wildfire on the presence...

Beginning in the 1950s, researchers of the United States Department of Agriculture Forest Service established a series of paired watershed studies throughout north-central and eastern Arizona. A total of nine experimental watershed areas were established in the pinyon-juniper and chaparral woodlands, as well as the ponderosa pine and mixed conifer forests. While most of the experiments were "mothballed" in the early 1980s, a few studies continued until the early 1990s. Several were recently reinstated while others were never closed. Drought conditions in the southwestern part of the USA,...

Ecosystem-based forest management requires long planning horizons to incorporate forest dynamics - changes resulting from vegetation growth and succession and the periodic resetting of these by natural and anthropogenic disturbances such as fire, wind, insects, and timber harvests. Given these dynamics, ecosystem-based forest management plans should specify desired conditions such as tree species composition, age class, tree density and structure, size and density of snags and course woody debris, and the size, shape, and juxtaposition of trees, groups of trees, and stands in order to...

Juniper (Juniperus spp.) encroachment into sagebrush (Artemisia spp.) and bunchgrass communities has reduced understory plant cover and allowed juniper trees to dominate millions of hectares of semiarid rangelands. Trees are mechanically masticated or shredded to decrease wildfire potential and increase desirable understory plant cover. When trees are masticated after a major increase in tree population density and associated decrease in perennial understory cover, there is a risk that invasive annual grasses will dominate because they are highly responsive to the increased resource...

Genetic techniques are frequently used to sample and monitor wildlife populations. The goal of these studies is to maximize the ability to distinguish individuals for various genetic inference applications, a process which is often complicated by genotyping error. However, wildlife studies usually have fixed budgets, which limit the number of geneticmarkers available for inclusion in a study marker panel. Prior to our study, a formal algorithm for selecting a marker panel that included genotyping error, laboratory costs, and ability to distinguish individuals did not exist. We developed a...

Metapopulation ecology has historically been rich in theory, yet analytical approaches for inferring demographic relationships among local populations have been few. We show how reverse-time multi-state capture­recapture models can be used to estimate the importance of local recruitment and interpopulation dispersal to metapopulation growth. We use 'contribution metrics' to infer demographic connectedness among eight local populations of banner-tailed kangaroo rats, to assess their demographic closure, and to investigate sources of variation in these contributions. Using a 7 year dataset,...

Sunflower family (Asteraceae). Limestone hawksbeard is a native perennial forb with one or two stems arising from a taproot. Plants are 30-70cm tall and basal leaves are 10-40 cm long, pinnatifid, with a fairly broad, undivided midstrip and entire or dentate segments. Plants are densely or sparsely gray-tomentulose. There are 10-60 heads per plant that are 7-12 flowered. The involucre is 10-12 mm high, tomentulose-puberulent, and the outer bracts are less than half as long as the mostly 7or 8 outer ones. The corollas are yellow, 14-30 mm long and the achenes are 5.5-9 mm long, mostly...

Mortality and crown dieback of quaking aspen (Populus tremuloides) were extensive on the Williams Ranger District, Kaibab National Forest in northern Arizona. We collected data from a random sample of 48 aspen sites to determine the relationship of predisposing site and stand factors and contributing agents to ramet mortality. Mortality of overstory (P10.1 cm DBH) aspen stems averaged 50% (44% by basal area). Pine-oak type aspen stands suffered greater basal area mortality (57%) than stands in mixed conifer type (38%). An average of 48% of live overstory aspen stems had >33% crown dieback,...

We used snow-tracking surveys to determine the probability of detecting Canada lynx Lynx canadensis in known areas of lynx presence in the northern Rocky Mountains, Montana, USA during the winters of 2006 and 2007. We used this information to determine the minimum number of survey replicates necessary to infer the presence and absence of lynx in areas of similar lynx density (approximately 2.8 lynx/100 km2) with confidence. The probability of detecting lynx in mountainous habitats that support resident populations was 0.80-0.99 when surveys were conducted on an 838 km2 grid with 10 km of...

Wildfires characterized by large areas of high severity are increasingly occurring in ponderosa pine (Pinus ponderosa P. & C. Lawson) forests of the Southwest to extents that are out of the natural range of variability. Managers are now routinely applying thinning and/or burning treatments to reduce fire severity. To investigate the effects of pre-fire treatments and fire severity on post-fire vegetation recovery, we re-measured established plots on the 2002 Rodeo-Chediski Fire on the White Mountain Apache Tribal (WMAT) lands eight years post-fire and the Apache-Sitgreaves National Forest...