Treesearch

Anticipated increases in the frequency and severity of wildfire may threaten the persistence of native salmonid populations in headwater streams in western North America. This study used extensive pre- and postfire data to assess whether wildfire leads to hypothesized declines in native westslope cutthroat trout Oncorhynchus clarkii lewisi and bull trout Salvelinus confluentus populations along with increases in the prevalence and abundance of nonnative brook trout S. fontinalis. Postfire cutthroat trout density was negatively correlated with the proportion of basin area that burned at...

Planting koa (Acacia koa A. Gray) in Hawai'i, USA aids in restoration of disturbed sites essential to conservation of endemic species. Survival and growth of planted seedlings under vegetative competition typically increases with initial plant size. Increasing container size and fertilizer rate may produce larger seedlings, but high fertilization can lead to surface and groundwater pollution and relatively low fertilizer use efficiency. Subirrigation systems may help mitigate this problem. Our study objective was to evaluate koa seedling growth with overhead or subirrigation over a range...

The density correction theory of Webb et al. (1980, Q J Roy Meteorol Soc 106: 85-100, hereafter WPL) is a principle underpinning the experimental investigation of surface fluxes of energy and masses in the atmospheric boundary layer. It has a long-lasting influence in boundary-layer meteorology and micrometeorology, and the year 2010 marks the 30th anniversary of the publication of the WPL theory. We provide here a critique of the theory and review the research it has spurred over the last 30 years. In the authors' opinion, the assumption of zero air source at the surface is a fundamental...

Ruffed grouse (Bonasa umbellus) are a popular game bird and the management indicator species for quaking aspen (Populus tremuloides) in the Black Hills National Forest (BHNF), which requires development of a robust monitoring protocol to evaluate trends in ruffed grouse populations. We used roadside drumming surveys in spring 2007 and 2008 to estimate ruffed grouse occupancy and detection probabilities in the BHNF while simultaneously assessing the influence of sampling and site covariates on these processes. Ruffed grouse occupancy estimates were constant between spring 2007 and 2008 (Ψ =...

Ruffed grouse (Bonasa umbellus) are important game birds that depend on multiple forest age-classes of aspen (Populus spp.) for food and cover, which makes them an appropriate management indicator species for the condition of quaking aspen (Populus tremuloides) communities in the Black Hills National Forest of western South Dakota and northeastern Wyoming (BHNF). Recent landscape-scale drumming surveys showed that occupancy of ruffed grouse in the BHNF depended primarily on the amount of aspendominated vegetation within a 95 ha site. However, an investigation of drumming site characteristic...

The generalist fungal pathogen Pyrenophora semeniperda occurs primarily in cheatgrass (Bromus tectorum) seed banks, where it causes high mortality. We investigated the relationship between this pathogen and its cheatgrass host in the context of fire, asking whether burning would facilitate host escape from the pathogen or increase host vulnerability. We used a series of laboratory and field experiments to address the ability of host seeds and pathogen life stages to survive fire. First, we determined the thermal death point (TDP50; temperature causing 50% mortality) of seeds and pathogen...

In the sawmill sector of the forest products industry, the clustering of mills and wide variation in forest stocking and ownership result in sawlog markets that are complex and spatially differentiated. Despite the inherent spatial attributes of markets for stumpage and logs, few studies have used geospatial methods to examine wood procurement in detail across political boundaries. This article provides a visual representation of wood procurement pressure across the Northern Forest region of the northeastern United States based on a spatial analysis of woodshed maps provided by 273...

Broadleaf herbicides are commonly used in rangelands to suppress exotic weeds and release native communities from negative impacts of invasion. However, few studies have comprehensively evaluated treatment effects on differing community components across a gradient of initial invasion levels.We conducted a 6-yr experiment within grasslands of western Montana to measure localscale effects of a broadcast application of picloram on 1) cover of the target invader, spotted knapweed (Centaurea stoebe L.), 2) prevalence of native functional groups, and 3) the secondary invader cheatgrass (Bromus...

Reliable estimates of population parameters are necessary for effective management and conservation actions. The use of genetic data for capture­recapture (CR) analyses has become an important tool to estimate population parameters for elusive species. Strong emphasis has been placed on the genetic analysis of non-invasive samples, or on the CR analysis; however, little attention has been paid to the simultaneous overview of the full noninvasive genetic CR analysis, and the important insights gained by understanding the interactions between the different parts of the technique. Here, we...

Heat waves are expected to become more frequent and severe as climate changes, with unknown consequences for biodiversity. We sought to identify ecologically-relevant broad-scale indicators of heat waves based on MODIS land surface temperature (LST) and interpolated air temperature data and assess their associations with avian community structure. Specifically, we asked which data source, time periods, and heat wave indices best predicted changes in avian abundance and species richness. Using mixed effects models, we analyzed associations between these indices and data from the North...