Treesearch

Effects of cool-season and warm-season prescribed burning treatments and a wildfire on tree overstories in oak savannas on the Cascabel Watersheds of the Southwestern Borderlands Region are reported in this paper. Information on the initial survival, levels of crown damage, species compositions and densities, annual growth rates, and basal sprouting following these burning events is presented. Impact of the fires on spatial distributions of trees in the overstories is also described. These events were all of low fire severities. As a consequence, effects of the prescribed burning treatments...

Historically, flood was the primary disturbance structuring riparian plant and animal communities in the southwestern United States. In many areas, however, livestock grazing and wildfire occur more frequently than flooding. Research has shown that changes in flood and fire frequency affect the composition of riparian surface-active arthropod communities (Bess et al. 2002, Ellis et al. 2001). Less is known about effects of grazing on these species. In this paper, we report abundances of the predatory pallid wind scorpion (Eremobates pallipes) in riparian forest plots subjected to flooding,...

The U.S. Forest Service (FS) has a long, shared history with the Spanish and Mexican land grants of northern New Mexico. The Treaty of Guadalupe Hidalgo, which ended the war between the United States and Mexico, was supposed to recognize and respect the property rights of the resident Hispano population. In many cases the intent of the Treaty was not honored. During the land grant adjudication processes after U.S. conquest of the region in 1848, much community land from these grants was declared public domain, eventually becoming part of the northern New Mexico national forests. Other...

Plague, caused by the bacterium Yersinia pestis, remains a threat to human and wildlife populations in the Western United States (Gage and Kosoy 2005). Several rodent species have been implicated as important maintenance hosts in the U.S., including Peromyscus maniculatus and Dipodomys spp. Fleas are a critical component of plague foci (Gage and Kosoy 2005). Transmission of plague increases with flea abundance and prevalence (Eisen et al. 2006; Lorange 2005). Prairie dogs (Cynomys gunnisoni) which have little innate immunity experience mortality in excess of 99% when exposed to plague...

Steppe, a mid-latitude, semiarid grassland has a wide global distribution. It is estimated that in the United States less than 23 percent of true shortgrass steppe still exists in native vegetation (National Grasslands Management Review Team Report, 1995). The Kiowa National Grassland long-term, 18-year, experimental fire research site is one such area. Located in the southern Great Plains, the site still contains most of its native vegetation. The site has never been plowed, although it was grazed by livestock until 1990 (Ford and Johnson, 2006). Information about natural ecosystem...

We evaluated existing literature on predicted and known climate change effects on terrestrial rangeland birds. We asked the following questions: 1) How does climate change affect birds? 2) How will birds respond to climate change? 3) Are species already responding? 4) How will habitats be impacted?

Many amphibian populations have declined drastically in recent years due to a large number of factors including the emerging threat of climate change (Wake 2007). Rangelands provide important habitat for amphibians. In addition to natural wetlands, stock tanks and other artificial water catchments provide habitat for many amphibian species (Euliss et al. 2004).

Previous accounts of polyploidy in the North American salt desert shrub Atriplex confertifolia (shadscale) have dealt with the distribution of polyploidy and the morphological and secondary chemical differences between races. The present study amplifies these studies and reveals additional ploidy-flavonoid races, with ploidy levels known to extend from 2x to 12x, and all except 2x and 12x represented by races with and without 6-methoxylation of flavonol compounds. Results of this study show that diploids across their range have about 113% as much DNA per genome as do polyploids and that...

Premise of the study: Artemisia subgenus Tridentatae plants characterize the North American Intermountain West. These are landscape-dominant constituents of important ecological communities and habitats for endemic wildlife. Together with allied species and genera (Picrothamnus and Sphaeromeria), they make up an intricate series of taxa whose limits are uncertain, likely the result of reticulate evolution. The objectives of this study were to resolve relations among Tridentatae species and their near relatives by delimiting the phylogenetic positions of subgenus Tridentatae species with...

Riparian woodlands of aspen (Populus tremuloides) provide valuable breeding habitat for several cavity-nesting birds. Although anecdotal information for this habitat is available for Lewis's Woodpecker (Melanerpes lewis), no study has previously examined the importance of aspen woodlands to this species' breeding biology. From 2002 to 2004, we monitored 76 Lewis's Woodpecker nests in aspen riparian woodlands of south-central Idaho to describe nest-site characteristics and estimate the nests' survival. We quantified the vegetation at nest sites and randomly selected other sites to determine...