Publications

The potential for increased drought frequency and severity linked to anthropogenic climate change in the semi-arid regions of the southwestern United States (US) is a serious concern. Multi-year droughts during the instrumental period and decadal-length droughts of the past two millennia were shorter and climatically different from the future permanent, ‘dust-bowl-like’ megadrought...

Th e Northwestern Forested Mountains are ecologically diverse and geographically widespread, encompassing the mountain ecosystems of central and northwestern North America (CEC 1997; Figure 2.2). Th e ecoregion description is adapted from CEC (1997). Geographically, they extend from the Rocky Mountains and the Sierra Nevada north through the Siskiyous, the east side of the Cascade Range...

New invasions, better field data, and novel spatial-modeling techniques often drive the need to revisit previous maps and models of invasive species. Such is the case with the at least 10 species of Tamarix, which are invading riparian systems in the western United States and expanding their range throughout North America. In 2006, we developed a National Tamarisk Map by using a...

Range-edge dynamics and anthropogenic fragmentation are expected to impact patterns of genetic diversity, and understanding the influence of both factors is important for effective conservation of threatened wildlife species. To examine these factors, we sampled greater sage-grouse (Centrocercus urophasianus) from a declining, fragmented region at the northern periphery of the species’...

We investigated canine teams (dogs and their handlers) on Guam as a potential tool for finding invasive brown treesnakes (Boiga irregularis) in the wild. Canine teams searched a 40 × 40 m forested area for a snake that had consumed a dead mouse containing a radio-transmitter. To avoid tainting the target or target area with human scent, no snake was handled or closely approached prior to...

Greater sage-grouse (Centrocercus urophasianus) have been declining both spatially and numerically throughout their range because of anthropogenic disturbance and loss and fragmentation of sagebrush (Artemisia spp.) habitats. Understanding how sage-grouse respond to these habitat alterations and disturbances, particularly the types of disturbances and extent at which they respond, is...

Twenty one polymorphic microsatellite loci for the Japanese dace (Tribolodon hakonensis) were isolated and characterized. The number of observed alleles per locus in 32 individuals ranged from 3 to 30. The observed and expected heterozygosities ranged from 0.125 to 0.969 and from 0.175 to 0.973, respectively. All loci conformed to Hardy–Weinberg equilibrium, no linkage disequilibrium was...

Boa constrictor is often referred to as a sit-and-wait or ambush forager that chooses locations to maximize the likelihood of prey encounters (Greene 1983. In Janzen [ed.], Costa Rica Natural History, pp. 380-382. Univ. Chicago Press, Illinois). However, as more is learned about the natural history of snakes in general, the dichotomy between active versus ambush foraging is becoming...

A bait tube is a device with which a toxicant inserted in a dead mouse (Mus musculus) can be delivered to invasive brown treesnakes (Boiga irregularis) with low risk of non-target bait take. We tested two bait tube designs in a 5ha snake enclosure where the identity of virtually every snake is known. Instead of using toxicants, we implanted radio transmitters in small (6.6±1.4 g) and...

: Effective conservation metrics are needed to evaluate the success of management in a rapidly changing world. Reproductive rates and densities of breeding birds (as a surrogate for reproductive rate) have been used to indicate the quality of avian breeding habitat, but the underlying assumptions of these metrics rarely have been examined. When birds are attracted to breeding areas in...

Freshwater aquatic ecosystems include rivers and streams, large and small lakes, reservoirs, and ephemeral ponds. Wetlands are defi ned and discussed in Chapter 17 of this report. It is estimated that there are 123,400 lakes with a surface area greater than 4 ha in the United States. Most lakes, however, are smaller than 4 ha; small lakes account for the majority of lake surface area...

The Pacific sheath-tailed bat (Emballonura semicaudata rotensis) and Mariana swiftlet (Aerodramus bartschi) are two rare insectivorous taxa restricted to the southern Mariana Islands in western Micronesia. It is believed that populations of both have dwindled because of impacts to their food resources. However, there is little information on the food habits of A. bartschi and none exists...