Treesearch

Early studies of plant response to ozone (O3) utilized concentration-based metrics, primarily by summarizing the commonly monitored hourly average data sets. Research with the O3 concentration parameter led to the recognition that both peak concentrations and cumulative effects are important when relating plant response to O3. The US and Canada currently use O3 concentration-based (exposure-based) parameters for ambient air quality standards for protecting vegetation; the European countries use exposure-based critical levels to relate O3 to vegetation response. Because plant response is...

The Orchard Display Nursery was planted on November 16, 2004 in cooperation with the Great Basin Native Plant Selection and Increase Project. The nursery includes 82 accessions of 27 native and introduced grass, forb and shrub species. Each accession was planted in 7 X 60 foot plots. See Tilley et al (2005) for descriptions of the species and accessions planted. The remaining area was planted to a cover crop mix of 50% Anatone bluebunch wheatgrass, 20% Bannock thickspike wheatgrass, 20% Magnar basin wildrye and 10% Snake River Plains fourwing saltbush. The test site is located on a loamy...

Purple prairie-clover (Dalea purpurea Ventenat) is a common perennial forb that flowers during mid-summer throughout the Great Plains and adjacent biomes. Seed of D. purpurea is used for prairie restoration. This study characterizes the reproductive biology of D. purpurea. Manual pollination field trials showed that D. purpurea has a mixed pollination system. It is primarily xenogamous (45% of flowers manually pollinated with outcross pollen yielded plump seeds), but partially self-compatible (19% of selfed flowers yielded seeds). Flowers neither visited by bees nor manually pollinated...

The Random Forests multiple regression tree was used to develop an empirically-based bioclimate model for the distribution of Pinus albicaulis (whitebark pine) in western North America, latitudes 31° to 51° N and longitudes 102° to 125° W. Independent variables included 35 simple expressions of temperature and precipitation and their interactions. These climate variables were derived from a spline climate model that provides point estimates (latitude, longitude, and altitude). The analysis used presence-absence data from more than 119,000 plot locations largely from USDA Forest Inventory...

Direct mortality of forest wildlife due to fire is rarely documented. In June and July 2004, the Nuttall Complex Fire burned 11,898 ha in the Pinaleno Mountains, southeastern Arizona. Portions of these mountains serve as the only habitat of endangered Mount Graham red squirrels (Tamiasciurus hudsonicus grahamensis). Survival of radio-collared red squirrels over a period that included the fire was lower in areas that were burned than on unburned areas; however, the majority of squirrels on our study areas survived the fire. Distance of nests from middens did not differ between pre-fire and...

The Point Arena mountain beaver (Aplodontia rufa nigra) is an endangered subspecies. Efforts to recover this sub-species will be aided by advances in molecular genetics, specifically the ability to estimate population size using noninvasive genetic sampling. Here we report on the development of nine polymorphic loci for the Point Arena mountain beaver. These markers provide us sufficient power to distinguish individuals, and thus can be used for calculating population size and delineating population substructure.

Connectivity is a key consideration for the management and conservation of any species, but empirical characterizations of connectivity can be extremely challenging. Assessments of connectivity require biologically realistic classifications of landscape structure (Kotliar and Wiens 1990), and an understanding of how landscape structure affects migration, dispersal, and population dynamics (Dunning et al. 1992; Rosenberg et al. 1997; Hanski 1999; Taylor et al. Chapter 2). Empirical assessments of connectivity may be accomplished by studying spatial patterns of habitat occupancy through time...

For four years during graduate school, I obtained a permit to conduct fisheries research in Rocky Mountain National Park in Colorado. The permit always stipulated, "Research shall be conducted out of the sight and sound of park visitors." I never understood the reason for this rule. Perhaps visitors might consider my research methods harsh. (Certainly the fish - captured by electrofishing and regurgitating their gut contents for the benefit of science - would think so.) Perhaps seeing a researcher at work, deep in the backcountry, would interfere with a visitor's nature experience. A...

Dormant hardwood cuttings are sections of woody stems that can develop into new plants complete with stems, leaves, and roots. Cuttings differ from seedlings because all new daughter plants that arise from cuttings are genetically identical to the parent plant. Cuttings can be long or short, depending on how they are used.

High severity wildfires have been increasing across southwestern ponderosa pine forests in recent decades. As the effects of wildfire become more widespread across the landscape, the need for information about the ecological effects of fire on understory vegetation is mounting. We investigated understory plant community response to the Rodeo-Chediski fire by conducting parallel studies on the White Mountain Apache Tribal lands (WMAT) and the Apache-Sitgreaves National Forests (A-S). We estimated plant canopy cover by species and quantified total plant species richness on 1000m2 plots. We...