Peromyscus boylii (Rodentia: Cricetidae)

Peromyscus boylii (Baird, 1855), the brush deermouse, is a common cricetid rodent in the southwestern United States and Mexico. It is a member of the Peromyscus boylii species group and has had a complicated taxonomic history because many former subspecies have been elevated to species. It is a medium-sized Peromyscus with small ears and a long, slightly bicolored and slightly haired tail that ends in a tuft of long hairs. It prefers brushy habitat, showing an affinity for oak–scrub oak and canyon–creek bottoms. It is not of special conservation concern

Elephants, woodlands and biodiversity in southern Africa.

When elephant densities exceed approximately 0.5 per km[2], savanna woodlands are generally converted to shrub-lands or grasslands. The impact of such elephant-mediated habitat change on biodiversity in African game reserves has seldom been measured. We examined species richness of woody plants, birds, bats, mantises and ants in reserves where elephants had destroyed the miombo woodland and in adjacent but intact miombo woodlands outside the reserves. Species richness of woodland birds and ants was significantly lower where elephants had removed the tree canopy. Our findings may have important policy implications for conserving biodiversity in many African reserves in the face of rapidly growing elephant populations (approximately 5% per annum). The problem is further compounded by international public pressures against reducing elephant densities within game reserves while, outside these protected areas, savanna woodlands and their associated faunas are being lost to agriculture. Where then will refugia for habitat-sensitive species exist if not within the region's largest protected areas

Tree roost selection by bats: an empirical synthesis using meta-analysis.

Over the past 2 decades, we have begun to accumulate a basic understanding of the roosting and foraging ecology of temperate insectivorous bats in forests. As our understanding improves, it is not surprising there should be attempts at synthesizing our knowledge to prioritize future research directions (e.g., Hayes 2003, Miller et al. 2003). Miller et al. (2003) reviewed results of 56 papers (1980-2001) and concluded that current data were unreliable because of small sample sizes, the short-term nature of studies, pseudoreplication, inferences beyond the scale of data collected, study design, and limitations of bat detectors and statistical analyses. Our concern is that this type of narrative synthesis that highlights limitations ignores any quantitative patterns that may exist. in this study we assess whether general patterns in North American bat use of roost trees and stand characteristics are robust enough to distill from the published literature. We used a series of meta-analyses on the same set of studies cited by Miller et al. (2003) to assess whether limitations of the current data warrant exclusion of bats from management recommendations. We used a second series of meta-analyses incorporating more recent data to determine the best current synthesis of knowledge on bat use of forests for roosting. In a third and fourth series of meta-analyses, we separated studies done on bats roosting in cavities versus roosting in foliage. in general, we found that, relative to other trees in the forest, the roost trees of bats were tall with large DBH in stands with open canopy and high snag density. In contrast, roost trees of bats did not differ from random trees with respect to live-tree density. The main differences we detected between foliage- and cavity-roosting bats were in percent canopy cover and distance to water. The roost trees of cavity-roosting species had more open canopies and were closer to water than random trees. Our results clearly show that significant patterns can be detected from the literature when data sets are combined using a meta-analytic approach

Production of ultrasonic vocalizations by Peromyscus mice in the wild.

Background: There has been considerable research on rodent ultrasound in the laboratory and these sounds have been well quantified and characterized. Despite the value of research on ultrasound produced by mice in the lab, it is unclear if, and when, these sounds are produced in the wild, and how they function in natural habitats. Results: We have made the first recordings of ultrasonic vocalizations produced by two free-living species of mice in the genus Peromyscus (P. californicus and P. boylii) on long term study grids in California. Over 6 nights, we recorded 65 unique ultrasonic vocalization phrases from Peromyscus. The ultrasonic vocalizations we recorded represent 7 different motifs. Within each motif, there was considerable variation in the acoustic characteristics suggesting individual and contextual variation in the production of ultrasound by these species. Conclusion: The discovery of the production of ultrasonic vocalizations by Peromyscus in the wild highlights an underappreciated component in the behavior of these model organisms. The ability to examine the production of ultrasonic vocalizations in the wild offers excellent opportunities to test hypotheses regarding the function of ultrasound produced by rodents in a natural context

Intraspecific Variation in Roost-site Selection by Little Brown Bats (<i>Myotis lucifugus</i>)

Although many species of bats select roost sites in large trees that are in open areas, intraspecific variation in roost-site selection may exist. We collected data on the roosting behaviour of little brown bats in the Cypress Hills, Saskatchewan, to determine the extent of intraspecific variation in roost-site selection. In addition, we examined the thermal microclimate of the tree-roosts selected by bats, to determine if roost-microsite variation can explain why certain cavities are selected over others. We found little brown bats roosting in trees as well as buildings. With the exception of a male who roosted in a spruce (Picea glauca) stump, tree-roosts selected by male and female little brown bats were all in trembling aspen (Populus tremuloides) trees. We found variation in roost-site fidelity and differential use of torpor by male bats. Temperatures within conifer snag cavities differed from aspen cavities during the day, and mirrored ambient temperature, which tended to be warmer than aspen cavities. We propose that bats select cavities in aspens because they are susceptible to heart rot. Aspen trees with heart rot provide cavities with an intact sapwood shell that protects bats against harsh ambient conditions as well as predators, and provides a unique thermal microclimate. Our results suggest that the origin of a roost site may be unimportant to a bat, provided certain other requirements are met

Hard forest edges act as conduits, not filters, for bats

High levels of bat activity have been reported at forest edges worldwide, but few studies have examined the ecological function of edges as a linear landscape feature. Patterns of association of bats at edges between old and young forest stands (hard edges) could be a result of edges acting as either a semi-permeable barrier or a filter to movement into the forest between different-aged forest stands for bats (or their insect prey), causing an accumulation of bat activity along the edge. Alternatively, edges may be a linear landscape feature similar to roads and riparian corridors that bats use as flight conduits as they move from one place to another. Using ultrasound microphone arrays and recording equipment, we were able to determine flight patterns of bats at hard edges within a landscape of intensively managed loblolly pine (Pinus taeda) plantation in eastern North Carolina, USA, during 2009. Across edges and species sampled, bats consistently flew parallel to edges, suggesting that edges act as conduits for bats. Feeding rates of bats at edges were low, further supporting use of edges as conduits for bats that are either flying along edges to move to and from roosting and foraging habitat patches or moving among foraging patches. Continuous edges should be maintained between linear and nonlinear landscape features, especially where known roosting and foraging areas are being connected by an edge

Bat Ecology [book review]

A broad review of bat ecology is timely because of advances over the past two decades in the technical approaches to the study of bats in an ecological and evolutionary framework. These advances include, but are not limited to, a range of ultrasonic detection methods, radio-telemetry, transponders, stable isotopes, bio-informatics, and molecular markers. Not surprisingly, since the publication of the Ecology of Bats (Kunz, 1982), our knowledge about the field of bat ecology has advanced. Bat Ecology attempts to summarize this advance through a mix of review and analytical chapters. Each chapter provides some historical perspective as well as highlights recent advances and suggests future directions. The editors divide the book into three main sections: Life History and Social Biology, Functional Ecology, and Macroecology. Within each of these sections are chapters written by authorities in the field

Can External Radiotransmitters be used to Assess Body Temperature and Torpor in Bats?

We tested externally applied, temperature-sensitive, radiotransmitters for determining the body temperature of big brown bats (Eptesicus fuscus) in various ambient temperatures (2- 260C). There was a slight, but significant, effect of ambient temperature on skin temperature (measured by the transmitters), but skin temperature accurately reflected rectal temperature in torpid and active bats, and it was never &gt;3.30C below rectal temperature. External radiotransmitters are, thus, useful in studies of torpor in bats, even when only small decreases in body temperature occur

Secondary Use of Aspen Cavities by Tree-Roosting Big Brown Bats

To further explore natural roost-site selection by temperate bats, we examined the use of tree roost sites by big brown bats (Eptesicus fuscus) in the West Block of Cypress Hills Provincial Park, Saskatchewan, an area where the number of human structures is limited. In this area, we found big brown bats roosted exclusively in cavities of trembling aspen trees (Populus tremuloides), despite the availability of cavities in snags of conifer trees. Most cavities had been excavated and previously used by yellow-bellied sapsuckers (Sphyrapicus varius). The use of aspens by sapsuckers relates to the relatively soft wood and susceptibility to heart rot of these trees, which provide ideal conditions for nesting: decayed heartwood with a firm sapwood shell. Orientation of cavity entrances was close to due south. The width of bats and the width of cavity entrances differed, suggesting that bats are not using roosts for protection from predators or exclusion of competitors. Bats showed fidelity to a particular group of roost trees because, despite roost switching, bats reunited in subsequent roost sites. During the day, temperatures in aspen cavities were approximately 50C cooler than in cavities of conifer snags. Microclimate differences, including temperature, may be why aspen cavities are selected over available cavities in conifer snags. All of the randomly selected cavities in aspen that we searched showed evidence of use by bats, which suggests roost sites for big brown bats in southwestern Saskatchewan may be a limiting resource

Effect of Removal of Woody Biomass after Clearcutting and Intercropping Switchgrass (Panicum virgatum) with Loblolly Pine (Pinus taeda) on Rodent Diversity and Populations

Plant-based feedstocks have long been considered viable, potential sources for biofuels. However, concerns regarding production effects may outweigh gains like carbon savings. Additional information is needed to understand environmental effects of growing feedstocks, including effects on wildlife communities and populations. We used a randomized and replicated experimental design to examine initial effects of biofuel feedstock treatment options, including removal of woody biomass after clearcutting and intercropping switchgrass (Panicum virgatum), on rodents to 2 years post-treatment in regenerating pine plantations in North Carolina, USA. Rodent community composition did not change with switchgrass production or residual biomass removal treatments. Further, residual biomass removal had no influence on rodent population abundances. However, Peromyscus leucopus was found in the greatest abundance and had the greatest survival in treatments without switchgrass. In contrast, abundance of invasive Mus musculus was greatest in switchgrass treatments. Other native species, such as Sigmodon hispidus, were not influenced by the presence of switchgrass. Our results suggest that planting of switchgrass, but not biomass removal, had species-specific effects on rodents at least 2 years post-planting in an intensively managed southern pine system. Determining ecologicalmechanisms underlying our observed species associations with switchgrass will be integral for understanding long-term sustainability of biofuels production in southern pine forest