Treesearch

Malammalian carnivores are considered particularly sensitive indicators of environmental change. Information on the distribution of carnivores from the early 1900s provides a unique opportunity to evaluate changes in their distributions over a 75-year period during which the influence of human uses of forest resources in California greatly increased. We present information on the distributions of forest carnivores in the context of two of the most significant changes in the Sierra Nevada during this period: the expansion of human settlement and the reduction in mature forests by timber...

Cuticular hydrocarbons (CHCs) are valuable characters for the analysis of cryptic insect species with few discernible morphological characters. Yet, their use in insect systematics, speciWcally in subterranean termites in the genus Reticulitermes (Isoptera: Rhinotermitidae), remains controversial. In this paper, we show that taxonomic designations in Reticulitermes from California (USA) suggested in light of diVerences among CHC phenotypes are corroborated by phylogenetic analyses using mtDNA sequences. Analyses based on CHC phenotypes and supported, in part, by behavioral and ecological...

Abstract. Natural and anthropogenic fi re once played an important role in oak woodlands of California. Although lightning-ignited fi res were infrequent, the California Indians used fi re to modify oak woodland vegetation for at least 3,000 yr. These high-frequency, low-intensity fi res likely resulted in little mortality of mature oaks, low but continuous tree recruitment, an open understory, and a fi ne-grained mosaic of vegetation patches. Following settlement by Europeans in the mid-1800s, ranchers burned to reduce shrub cover and to increase grassland area and forage production;...

Southern California, recognized as a major center of biodiversity, contains some of the most diverse habitats of any landscape in North America. The ever-expanding human population of the region desires land, water, resources, and recreation, creating conflict with the habitat requirements of many rare species. Managing resources in a way that maximizes biodiversity in remaining habitats, while providing opportunities for other appropriate uses of the land, presents a formidable challenge, requiring coordination between scientists and resource managers. The papers in this proceedings...

Development of biological control agents for weeds has been motivated by the need to reduce the abundance and distribution of a pest plant where chemical and mechanical control were not cost effective. Primary objectives have been direct reduction in abundance of the target and, secondarily, the increase of desirable species. Recently, wildland weeds have become a focus of biological control projects. Here, desired outcomes include both reduction of the target and indirect effects of increased diversity and abundance of native species and restoration of ecosystem services. However, goals...

The equivalency of willingness to pay between the states of California, Florida and Montana is tested. Residents in California, Florida and Montana have an average willingness to pay of $417, $305, and $382 for prescribed burning program, and $403, $230, and $208 for mechanical fire fuel reduction program, respectively. Due to wide confidence intervals, household WTP in the three states are not statistically different. Over all tests, there is mixed evidence on transferability, but California and Montana WTP are similar to each other for prescribed burning and Florida and Montana have...

Snakes have recently been proposed as model organisms for addressing both evolutionary and ecological questions. Because of their middle position in many food webs they may be useful indicators of trophic complexity and dynamics. However, reliable data on snake populations are rare due to the challenges of sampling these patchily distributed, cryptic, and often nocturnal species and also due to their underrepresentation in the ecological literature. Studying a diurnally active stream-associated population of garter snakes has allowed us to avoid some of these problems so that we could...

Ecosystems are rapidly being altered and destabilized on a global scale, threatening native biota and compromising vital services provided to human society. We need to better understand the processes that can undermine ecosystem integrity (resistance-resilience) in order to devise strategies to ameliorate this trend. We used a herpetofaunal assemblage to first assess spatial patterns of biodiversity and then to discover the underlying landscape processes likely responsible for these patterns. Reptiles and amphibians are a phylogenetically diverse set of species with documented sensitivity...

Lotic ecosystems are increasingly viewed as having three interactive spatial compartments, i.e., channel sediments, the hyporheic zone, and flood plains or riparian areas (Cummins et al. 1983; Ward 1989). The hyporheic zone is the sub-benthic habitat of interstitial spaces between substrate particles in the stream bed, and is the transition zone between surface flow and ground water (Boulton et al. 1998; Stanford and Ward 1988; White 1993). Extensive use of the hyporheic zone by invertebrates has been reported (Smock et al. 1992; Williams and Hynes 1974), but aside from several accounts of...

Oviposition sites and reproductive ecology of the southern-torrent salamander (Rhyacotriton variegatus) remain poorly documented. This species oviposits in cryptic locations making the detection of eggs difficult. Here we describe the discovery of 1 clutch of eggs of R. variegatus from northern California, which further expands our knowledge of their reproductive ecology.