Treesearch

Rapid global changes due to changing land use, climate, and non-native species are altering environmental conditions, resulting in more novel communities with unprecedented species combinations. Understanding how future anthropogenic changes may affect novelty in ecosystems is important to advance environmental management and ecological research in the Anthropocene. The main goal of this study was to understand how alternative scenarios of future land-use change may affect novelty in ecosystems throughout the conterminous United States. We used five spatially explicit scenarios of future...

BACKGROUND: The invasive goldspotted oak borer, Agrilus auroguttatus, is threatening the health and survival of oak trees in San Diego County, California. From two sites in the core area of the infestation, we report a 2.5 year investigation of the impact of A. auroguttatus on coast live oak, Quercus agrifolia, before and after treatment with two systemic insecticides, emamectin benzoate (EB) and imidacloprid (IC). RESULTS: None of the 446 survey trees died during the study. The crown dieback rating of most trees at both study sites remained unchanged, regardless of insecticide treatment....

Carbaryl is regarded among the most effective, economically viable, and ecologically-compatible insecticides available for protecting conifers from bark beetle attack in the western United States. Treatments are typically applied in spring prior to initiation of bark beetle flight for that year. We evaluated the efficacy of spring and fall applications for protecting individual lodgepole pine, Pinus contorta Dougl. ex Loud, from mortality attributed to mountain pine beetle, Dendroctonus ponderosae Hopkins, the most notable forest insect pest in western North America. Both spring and fall...

The great gray owl (Strix nebulosa) is listed by the state of California as endangered, with a population estimate of fewer than 300 individuals in the state. Nest-site availability has been suggested as a limiting factor for population growth in California, but information on nest types and nesting habitat has been based on a small number of nests that may not fully represent the variety of conditions used by the species. We collated all known nesting records in the Sierra Nevada mountains of California since 1973 (n=56) and then visited 47 of the nest sites to characterize habitat and...

Mountainous topography creates fine-scale environmental mosaics that vary in precipitation, temperature, insolation, and slope position. This mosaic in turn influences fuel accumulation and moisture and forest structure. We studied these the effects of varying environmental conditions across a 27,104 ha landscape within Yosemite National Park, California, USA, on the number of fires and burn severity (measured from Landsat data for 1984-2010) and on canopy cover at two heights (>2 m and 2-8 m) and dominant tree height (measured with airborne LiDAR data). We used site water balance (actual...

Procambarus (Girardiella) holifieldi, new species, is a primary burrowing crayfish from a low-lying field in Perry County, Alabama. It belongs to the Hagenianus Group in the subgenus Girardiella. The new species is morphologically most similar to Procambarus (Girardiella) barbiger. They differ in the size and shape of the caudal processes. Procambarus barbiger has a beard along the mesial margin of the palm of the chela, while the new species lacks the beard. In addition to the description of the new species, the Hagenianus Group is reviewed and new synonymies are provided. We demonstrate...

tThe presence of metro nature enables daily environmental interactions, and a substantial body of evi-dence now demonstrates that nature contact generates extensive psychosocial, cognitive, and physicalhealth and well-being benefits. Estimates of the economic values of such benefits have lagged similarvaluation efforts for environmental services (such as improved air and water quality). In this article,using a life course approach, we estimate the potential annual value of six metro nature benefits, andcautiously extrapolate to a national scale, based on best available data and research....

Nearly two decades of research on the host-pathogen interaction in fusiform rust of loblolly pine is detailed. Results clearly indicate that pathotype-specific genes in the host interacting with pathogen avirulence cause resistance as defined by the non-gall phenotype under favorable environmental conditions for disease development. In particular, nine fusiform rust resistance genes (Fr genes) are described here including the specific methods to determine each and their localization on the reference genetic map of loblolly pine. Understanding how these and other apparent Fr genes in...

Background: Disturbance is a key influence on forest carbon dynamics, but the complexity of spatial and temporal patterns in forest disturbance makes it difficult to quantify their impacts on carbon flux over broad spatial domains. Here we used a time series of Landsat remote sensing images and a climate-driven carbon cycle process model to evaluate carbon fluxes at the ecoregion scale in western Oregon. Results: Thirteen percent of total forest area in the West Cascades ecoregion was disturbed during the reference interval (1991-2010). The disturbance regime was dominated by harvesting...