Treesearch

We describe 46 new site records documenting occupancy by American pika (Ochotona princeps) at 21 locations from 8 mountain regions in the western Great Basin, California, and Nevada. These locations comprise a subset of sites selected from regional surveys to represent marginal, isolated, or otherwise atypical pika locations, and to provide information for assessing environmental tolerance limits. Several locations are known from historic observations (Madeline Plain, Bodie Mtns., Wassuk Mtns., Mono Craters) and are included here to update current status. Site elevations range from 1848 m...

Limited information is available on how soil and leaf populations of the sudden oak death pathogen, Phytophthora ramorum, may differ in their response to changing weather conditions, and their corresponding role in initiating the next disease cycle after unfavorable weather conditions. We sampled and cultured from 425 trees in six sites, three times at the end of a 3-year-long drought and twice during a wet year that followed. Soil was also sampled twice with similar frequency and design used for sampling leaves. Ten microsatellites were used for genetic analyses on cultures from successful...

This publication contains background information and guidance for resource management professionals and landowners to understand and manage sudden oak death (SOD) in California forests. The publication is divided into three chapters: Chapter 1 discusses the epidemiology of SOD in California and includes information on biology of the pathogen Phytophthora ramorum, host-pathogen interactions, disease spread, and environmental conditions that affect disease development. An understanding of these relationships is needed to choose the most appropriate strategies for managing SOD at a given...

Introduced fish reduce the abundance and diversity of native aquatic fauna, but the effect can be reduced in complex habitats. We manipulated fish populations in forested mountain lakes to determine whether or not fish affected benthic macroinvertebrate composition across lakes with differing habitat complexity. We compared abundance, biomass, body-length, and community structure of benthic macroinvertebrates from 16 lakes with three treatments (fish stocked, suspended stocking, fish removed) and unstocked fishless “controls.” Over four years, we assessed the relative importance of fish...

Amphibians are experiencing global declines due in part to the infectious disease chytridiomycosis. Some symbiotic bacteria residents on frog skin have been shown to inhibit the growth of Batrachochytrium dendrobatitis (Bd) but few studies have attempted to fully describe the resident bacterial flora of frog skin. We cultured and sequenced 130 bacterial isolates from frogs collected from the California Klamath Range, recovering predominantly Gram-negative bacteria from 20 higher order taxa and 31 genera. There were also a large number of unclassifiable isolates. Forty-three isolates were...

An international consensus has emerged that people living, working, and going to school near roads with high volumes of traffic face increased risks for adverse health effects (1), most likely from acute and chronic exposures to elevated levels of air pollution, including particulate matter (PM), gaseous criteria pollutants, and air toxics.

Estimates from molecular data for the fraction of new nonsynonymous mutations that are adaptive vary strongly across plant species. Much of this variation is due to differences in life history strategies as they influence the effective population size (Ne). Ample variation for these estimates, however, remains even when comparisons are made across species with similar values of Ne. An open question thus remains as to why the large disparity for estimates of adaptive evolution exists among plant species. Here, we have estimated the distribution of deleterious fitness effects (DFE) and the...

The Trinity River Restoration Program began in 2000 with the goal of restoring the Trinity River's salmon and steelhead fisheries, which were severely degraded during the last half-century as a result of dams, water diversions under the Central Valley Project, and land-use practices such as gold mining. The restoration program, as outlined in the U.S. Department of the Interior's Record of Decision (2000), was founded to restore the fisheries by restoring features of a healthy alluvial river system, such as spring floods, river channel complexity, and gravel spawning habitat.

Morphological variation of ponderosa pine (Pinus ponderosa Dougl. ex Laws.), growing north of Mexico, is described. A map shows distributions of five putative races that are analyzed and discussed. Characteristics of branches, shoots, and needles were measured for 10 or fewer trees growing on 147 plots located at 1,500-ft elevational intervals along latitudinal transects. Characteristics of cones were measured from 120 of these plots. Cones from 78 plots yielded seeds for study. Subspecific boundaries were based on both visual interpretations for many traits and statistical cluster...

Changes in forest carbon stocks can be detected through monitoring of deforestation (conversion of| forests to some other cover type), forest degradation (forests that remain forests), and/or reforestation| (restoration of forests). Techniques for monitoring deforestation and resultant changes to forest carbon| stocks are widespread and well published. However, techniques for monitoring degradation and| reforestation are relatively untested in developing countries despite their inclusion in current UNFCCC| REDD+ negotiations..