Treesearch

Bark beetles (Coleoptera: Curculionidae, Scolytinae) are important tree mortality agents in western coniferous forests. Protection of individual trees from bark beetle attack has historically involved applications of liquid formulations of contact insecticides to the tree bole using hydraulic sprayers. More recently, researchers looking for more portable and environmentally safe alternatives have examined the effectiveness of injecting small quantities of systemic insecticides directly into trees. In this study, we evaluated trunk injections of experimental formulations of emamectin...

Sequestered forest carbon can provide a climate change mitigation benefit, but in dry temperate forests, wildfire poses a reversal risk to carbon offset projects. Reducing wildfire risk requires a reduction in and redistribution of carbon stocks, the benefit of which is only realized when wildfire occurs. To estimate the time needed to recover carbon removed and emitted during treatment, we compared the 7-year post-treatment carbon stocks for mechanical thinning and prescribed fire fuels reduction treatments in Sierra Nevada mixed-conifer forest and modeled annual carbon accumulation...

One of the primary assumptions associated with many wildlife and population trend studies is that target species are correctly identified. This assumption may not always be valid, particularly for species similar in appearance to co-occurring species. We examined size overlap and identification error rates among Cooper's (Accipiter cooperii) and sharp-shinned (A. striatus) hawks specific to a raptor migration count station along the Pacific Coast of North America. Illustrating the difficulty of distinguishing between these 2 species, we found overlap in 7 metrics among species–sex groups...

The California spotted owl (Strix occidentalis occidentalis) is the only spotted owl subspecies not listed as threatened or endangered under the United States Endangered Species Act despite petitions to list it as threatened. We conducted a meta-analysis of population data for 4 populations in the southern Cascades and Sierra Nevada, California, USA, from 1990 to 2005 to assist a listing evaluation by the United States Fish and Wildlife Service. Our study areas (from N to S) were on the Lassen National Forest (LAS), Eldorado National Forest (ELD), Sierra National Forest (SIE), and Sequoia...

Investigations of regional genetic differentiation are essential for describing phylogeographic patterns and informing management efforts for species of conservation concern. In this context, we investigated genetic diversity and evolutionary relationships among great gray owl (Strix nebulosa) populations in western North America, which includes an allopatric range in the southern Sierra Nevada in California. Based on a total dataset consisting of 30 nuclear microsatellite DNA loci and 1938-base pairs of mitochondrial DNA, we found that Pacific Northwest sampling groups were recovered by...

West Nile virus (WNV) infection has caused high levels of mortality in North American hawks and owls. To investigate the extent of infection among raptors of conservation concern in the Sierra Nevada, we tested 62 Northern Goshawks (Accipiter gentilis), 209 Spotted Owls (Strix occidentalis), and 22 Great Gray Owls (Strix nebulosa) for WNV antibodies during the summers of 2004 to 2007 and compared our results with avian WNV mortalities detected by the California Department of Public Health. We detected no antibodies to WNV among the individuals tested. During the same period WNV RNA was...

In this investigation, we adapted identity theory (references) to reassess a conceptualization of place attachment – an attitudinal construct used by environmental psychologists to describe people‘s bonding to the physical landscape. Past work has conceptualized the construct in terms of three components; cognitive, affective and conative elements. Based on the tents of identity theory, we hypothesized that the cognitive component – reflected in the dimension place identity - is an antecedent of these other affective and conative facets. We empirically tested this reconceptualization using...

Few specimens of water mites have been collected from Pacific Island streams, especially higher elevation, head water streams. Uchida (1935, 1939) and Cook & Bright (1983) published 11 species of water mites from the Palau Islands, while Cook (1957) reported two Arrenurus species from the main island of Yap in the Caroline Island chain. Viets (1939) reported the occurrence of unnamed Arrenurus larvae from Hawaii, but Smit (2004) failed to find the adults. Smith & Cook (2004) described a new Piona species from Hawaii, but very likely this is an introduced species. During an inventory of...

Making complex risk-related decisions involves a degree of uncertainty. How that uncertainty is addressed or presented in reports or data tables can be tailored to meet information users’ needs and preferences. Involving the recipients of risk-related information in the design of information to be delivered (including the types of information delivered, format, and approach to risk) follows Fischoff’s (1995) recommendation for involving the recipients of risk information in the crafting of the risk message. Here, we describe a study conducted with people who use risk-related information....

Secusio extensa (Lepidoptera: Arctiidae) was evaluated as a potential biological control agent for Madagascar fireweed, Senecio madagascariensis (Asteraceae), which has invaded over 400 000 acres of rangeland in the Hawaiian Islands and is toxic to cattle and horses. The moth was introduced from southeastern Madagascar into containment facilities in Hawaii, and host specificity tests were conducted on 71 endemic and naturalized species (52 genera) in 12 tribes of Asteraceae and 17 species of non-Asteraceae including six native shrubs and trees considered key components of Hawaiian ecosystem...