Publications

We evaluated whether restoring tidal flow to previously diked estuarine wetlands also restores foraging and growth opportunities for juvenile Chinook Salmon Oncorhynchus tshawytscha. Several studies have assessed the value of restored tidal wetlands for juvenile Pacific salmon Oncorhynchus spp., but few have used integrative measures of salmon performance, such as habitat-specific growth...

We describe an efficient implementation of a 3D movement-based kernel density estimator for determining animal space use from discrete GPS measurements. This new method provides more accurate results, particularly for species that make large excursions in the vertical dimension. The downside of this approach is that it is much more computationally expensive than simpler, lower...

Although prescribed burns are used in many locations where reptiles are present, the effects of fire on reptiles are poorly understood. our objective was to determine the effects of prescribed fire on the Western yellow-bellied racer, Coluber constrictor mormon, at a study site in coastal san Mateo county, california. We sampled an unburned site and an adjacent prescribed burn site two...

Conservation efforts to restore historic waterbird distribution and abundance in the Central Valley of California require information on current and historic areas of waterbird habitat. To provide this information, we mapped the area of agricultural fields in the vicinity of the historic Tulare Lake Bed in the Tulare Basin, California, that were treated postharvest with two different...

The recovery strategy for an endangered species requires accurate knowledge of its distribution and geographic range. Although the best available information is used when developing a recovery plan, uncertainty often remains in regard to a species actual geographic extent. The arroyo toad (Anaxyrus californicus) occurs almost exclusively in coastal drainages, from Monterey County...

We studied the microhabitat characteristics of 747 egg masses of the federally-threatened Rana draytonii (California red-legged frog) at eight sites in California. our study showed that a broad range of aquatic habitats are utilized by ovipositing R. draytonii, including sites with perennial and ephemeral water sources, natural and constructed wetlands, lentic and lotic hydrology, and...

The mortality process is a key component of avian population dynamics, and understanding factors that affect mortality is central to grouse conservation. Populations of greater sage-grouse Centrocercus urophasianus have declined across their range in western North America. We studied cause-specific mortality of radio-marked sage-grouse in Eureka County, Nevada, USA, during two seasons...

Recent attempts to predict the response of large food webs to perturbations have revealed that in larger systems increasingly precise information on the elements of the system is required. Thus, the effort needed for good predictions grows quickly with the system's complexity. Here, we show that not all elements need to be measured equally well, suggesting that a more efficient...

To study potential effects of recreation activity on habitat use of desert bighorn sheep (Ovis canadensis nelsoni), we placed Global Positioning System collars on 10 female bighorn sheep within the Wonderland of Rocks–Queen Mountain region of Joshua Tree National Park (JOTR), California, USA, from 2002 to 2004. Recreation use was highest from March to April and during weekends throughout...

Greater sage-grouse Centrocercus urophasianus, hereafter sage-grouse, populations have declined across their range due to the loss, degradation, and fragmentation of habitat. Habitat alterations can lead not only to vegetative changes but also to shifts in animal behavior and predator composition that may influence population vital rates, such as nest success. For example, common ravens...

Subalpine meadows are some of the most ecologically important components of mountain landscapes, and primary productivity is important to the maintenance of meadow functions. Understanding how changes in primary productivity are associated with variability in moisture and temperature will become increasingly important with current and anticipated changes in climate. Our objective was to...

Numerous factors have contributed to declines in populations of the federally threatened Agassiz's Desert Tortoise (Gopherus agassizii) and continue to limit recovery. In 2010, we surveyed a low-density population on a military test facility in the northwestern Mojave Desert of California, USA, to evaluate population status and identify potential factors contributing to distribution and...