Treesearch

Bark beetles (Coleoptera: Curculionidae, Scolytinae) are commonly recognized as important tree mortality agents in coniferous forests of the western U.S.A. High stand density is consistently associated with bark beetle infestations in western coniferous forests, and therefore, thinning has long been advocated as a preventive measure to alleviate or reduce the amount of bark beetle-caused tree mortality. The objective of this study was to determine the effectiveness of thinning to reduce stand susceptibility to bark beetle infestations over a 10-year period in Pinus jeffreyi forests on the...

Whaling represents one of the most internationally controversial and highly polarized environmental issues of recent times. Arne Kalland, in Unveiling the Whale: Discourses on Whales and Whaling, examines the whaling issue from the perspective of a pro-whaling country with an emphasis on analysis of discourse in international arenas, primarily the International Whaling Commission (IWC). The excellent and fine-grained analysis focuses on the ways that different groups think and communicate about whales and the processes that have led to extreme polarization in international whale conservation.

Ambermarked birch leafminer, Profenusa thomsoni (Konow) (Hymenoptera: Tenthredinidae), is an exotic, invasive pest of urban and wildland birch, Betula spp., in portions of North America. Extensive defoliation of ornamental birch in Alaska requires that suitable control measures be evaluated and developed. Based on previous work, we evaluated the efficacy of emamectin benzoate (TREE-äge ®, Syngenta Crop Protection LLC, Greensboro, NC) for control of P. thomsoni in Interior Alaska. TREE-äge ® significantly reduced crown damage (percent leaf mining) compared to the untreated control. It...

In his new book, Bob Cabin uses his personal involvement in the restoration of Hawai'i dry forests to illustrate the tensions that he feels exists between the science and practice of ecological restoration. It is a journey that starts out among the multidisciplinary, multi-interest perspectives associated with a grass-roots communitybased working group (Part 1, Chapter 1-3), moves into the tedium of academic rigor (Part 1, Chapter 4-5), and culminates in an "aha!" moment, when he realizes that science is of limited value for restoration (Part 1, Chapter 6). His final resting point is...

Freshwater mussels use an array of strategies to transfer their parasitic larvae (glochidia) to fish hosts. We examined the effects of temperature, photoperiod, and female gravidity on mantle lure display and conglutinate release by Ligumia subrostrata (Say, 1831) in 2 laboratory experiments. In the 1st experiment, we examined the use of these strategies in 4 temperature treatments (5, 15, 25, 35°C) and 3 photoperiods (10:14, 12:12, and 14:10 h light: dark). In the 2nd experiment, we observed infection strategies under ambient conditions with flow-through pond water. Water temperature...

Interest in freshwater mussels is growing for two important reasons. First, freshwater mussels are among the most endangered organisms on Earth, and many species are already extinct or face imminent extinction. Their desperate conservation plight has gained intense interest from natural resource agencies, nongovernmental conservation organizations, academia, and industry, and mussels are now the centerpiece of conservation initiatives ranging from local watershed groups to global programs. Second, recent research on mussel ecology, spurred in large part by the needs of the conservation...

Two new blind snakes in the genus Ramphotyphlops are described from Ulithi (R. hatmaliyeb sp. nov.) and Ant Atoll (R.adocetus sp. nov.) in the Caroline Islands, the first blind snake species known from Micronesia east of Palau (excludingRamphotyphlops braminus). Both species are unusual in being known only from small, low-lying atolls. They can be distinguishedfrom other Ramphotyphlops by the combination of 22 scale rows over the length of the body; a wedge-shapedsnout, without a keratinized keel; and a broad, pyriform (R. adocetus) or ovate (R. hatmaliyeb) rostral scale.

In recent decades, invasive phloem and wood borers have become important pests in North America. To aid tree sampling and survey efforts for the newly introduced goldspotted oak borer, Agrilus auroguttatus Schaeffer (Coleoptera: Buprestidae), we examined spatial patterns of exit holes on the boles (trunks) of 58 coast live oak, Quercus agrifolia Née (Fagaceae), trees at five sites in San Diego County, southern California, United States of America. Agrilus auroguttatus exit hole densities were greater at the root collar than at mid-boles (6.1m above ground). Dispersion patterns of exit...

Understory shrubs play important ecological roles in forests of the western US, but they can also impede early tree growth and lead to fire hazard concerns when very dense. Some of the more common genera (Ceanothus, Arctostaphylos, and Prunus) persist for long periods in the seed bank, even in areas where plants have been shaded out. To determine shrub seed density and investigate the feasibility of managing shrub abundance by regulating the size of the soil seed bank with fire, we sampled the seed bank in 24 mixed conifer forest stands throughout northern California. Twenty stands were...

The positive relationship between species diversity (richness and evenness) and critical ecosystem functions, such as productivity, carbon storage, and nutrient cycling, is often used to predict the consequences of extinction. At regional scales, however, plant species richness is mostly increasing rather than decreasing because successful plant species introductions far outnumber extinctions. If these regional increases in richness lead to local increases in diversity, a reasonable prediction is that productivity, carbon storage, and nutrient cycling will increase following invasion, yet...