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1

Prey consumed by Corynorhinus townsendii ingens in the Ozark Mountain region

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Dodd L. E., Lacki M. J.
Acta Chiropterologica
|
2007
|
tom 09
|
nr 2
Moths are known to be the primary prey of the Ozark big-eared bat (Corynorhinus townsendii ingens); however, data do not exist as to which species, families, and sizes of moths are eaten. We investigated patterns of prey consumption of C. t. ingens from 2003 to 2005 by collecting discarded moth wings and other insect parts beneath roosts in three maternity areas: north-central Arkansas, northwest Arkansas, and northeast Oklahoma. A total of 42 visits to roosts resulted in 579 remnants of insect prey representing eight insect orders. Of the discarded remains, 57.2% (n = 331) were Lepidoptera, with 81.3% (n = 269) of these identified beyond the ordinal level. Moths representing eight families and 49 species were eaten by C. t. ingens. Noctuidae was the most common family occurring in the diet with 25 species represented. Noctuidae and Notodontidae were typical prey of C. t. ingens in all areas, but consumption of other moth families varied. Corynorhinus t. ingens preyed upon a limited size range of moths, consistent with data for Corynorhinus in other locations in eastern North America. Our data increase the number of species (n = 31), genera (n = 27), and families (n = 3) of moths known to be eaten by Corynorhinus. Because two of the new families of moths documented as prey of Corynorhinus were discovered beneath feeding roosts in Oklahoma on the western edge of our study, we suggest additional surveys are needed at feeding roosts of Corynorhinus in western North America to fully understand the diets of Corynorhinus.
2

A prospective power analysis and review of habitat characteristics used in studies of tree-roosting bats

100%
Lacki M. J., Baker M. D.
Acta Chiropterologica
|
2003
|
tom 05
|
nr 2
We identified 25 studies published between 1988 and 2001 that measured characteristics of roosting sites of tree-roosting bats, and where measures were compared to characteristics of random or available locations. The most frequently measured habitat characteristics were roost-tree diameter (n = 23), roost-tree height (21), roost-tree canopy cover (16), roost height (14), and slope (10). Habitat characteristics of the roost tree itself were measured more frequently than stand or landscape characteristics; a total of 31 different habitat characteristics was used to describe stand or landscape conditions as opposed to 23 different habitat characteristics used to describe features of the roost tree. The overall mean (± SE) number of habitat characteristics examined per study was 8.0 ± 1.1, with an average of 4.2 ± 0.7 characteristics reported to be significant (P < 0.05). Mean estimated effect size, or the absolute value of the difference between means divided by the population standard deviation, of habitat characteristics ranged from 0.83 to 1.52. A sample size of 11 radio-tagged bats was sufficient to achieve acceptable power, i.e., 0.80, for all habitat characteristics examined when only using the upper limit of the 95% confidence intervals for estimated effect sizes. In contrast, a sample size of 39 radio-tagged bats was sufficient in achieving the same level of power for only 50% of the habitat characteristics evaluated at the lower end of the 95% confidence intervals. We encourage researchers to conduct pilot studies, and estimate effect sizes and variances to assess the level of sampling effort required to evaluate habitat characteristics in studies of tree-roosting bats.
3

Temperatures beneath bark of dead trees used as roosts by myotis volans in forests of the Pacific Northwest, USA

81%
Lacki M. J., Johnson J. S., Baker M. D.
Acta Chiropterologica
|
2013
|
tom 15
|
nr 1
Few studies have examined temperatures inside bark roosts of tree-roosting bats. We measured temperatures beneath plates of exfoliating bark of six species of dead trees used for roosting by long-legged myotis (Myotis volans) from June to July 2003–2006 in Idaho and Oregon, USA, and compared these across tree species and with ambient temperature (TA). Temperature profiles beneath bark oscillated within the range of TA, demonstrating the ability of bark cavities on dead trees to insulate against daily extremes in maximum and minimum TA. Slope position affected the difference in bark cavity temperature from TA during daytime periods, with bark cavities on dead trees in upper slope positions being cooler than TA compared to bark cavities on dead trees in lower slope positions. Differences in bark cavity temperatures from TA varied among dead tree species during nighttime periods, with white fir (Abies concolor) and ponderosa pine (Pinusponderosa) warmer than TA compared to other dead tree species. Mean daily maximum temperatures beneath bark of dead white fir, grand fir (Abies grandis), western white pine (Pinus monticola), and ponderosa pine met or exceeded the theoretical lower critical temperature (TLC) of long-legged myotis (range = 29.7–30.5°C) within several hours of sunset, but were substantially colder for much of the day. These data indicate long-legged myotis roosting beneath bark of dead conifer trees likely experience temperatures conducive to use of torpor during early morning hours, with potential for passive re-warming in late afternoon facilitated by increases in daily temperatures beneath bark prior to evening emergence.
4

Social network analysis and the study of sociality in bats

81%
Johnson J. S., Kropczynski J. N., Lacki M. J.
Acta Chiropterologica
|
2013
|
tom 15
|
nr 1
Many bat species are known for being gregarious, forming mixed- or single-sex social groups commonly referred to as colonies. The number of studies investigating sociality in bats is rapidly increasing, with studies ranging from basic descriptions of the number of males and females within social groups to studies using social network analysis. Studies of sociality in bats are taking increasingly diverse approaches to data collection, analysis and interpretation, leaving researchers with an array of perspectives on how to conduct future research. These perspectives are difficult to synthesize, but an integrated understanding of pioneering works in this field should help researchers build upon what is already known about sociality in bats and formulate new hypotheses. Herein we provide a review of methodologies used to measure social interactions, relationships, and structure in bats. We review assumptions, sources of bias, strengths, and limitations of these methods. We emphasize that while all of the reviewed methods are well suited for assessing social interactions and relationships, each method will impact analyses of social structure and should be considered carefully. We encourage further use of social network analysis as a framework for conceptualizing, designing, and analyzing studies of bat sociality. We do not advocate any single network analysis methodology, as network analysis is continually evolving and no one technique is well suited for all research questions. Instead, we recommend several specific network measures we believe are appropriate for different types of research questions and datasets and discuss the strengths and limitations of popular analyses.
5

Seasonal and geographic trends in acoustic detection of tree-roosting bats

61%
Johnson J. S., Watrous K. S., Giumarro G. J., Peterson T. S., Boyden S. A., Lacki M. J.
Acta Chiropterologica
|
2011
|
tom 13
|
nr 1
Migratory routes, timing, and behavior ^rc some of the least studied facets of bat biology, and possibly play roles in bat mortality rates observed at commercial wind energy facilities. We used acoustic detectors to record seasonal activity of silver-haired (Lasionycteris noctivagans), hoary (Lasiurus cinereus), and eastern red (Lasiurus borealis) bats above the forest canopy at one existing and 13 proposed wind energy facilities in seven eastern U.S. states between April and November 2007 and 2008. We correlated species detection rates between surveys located within three predetermined geographic regions, and correlated species detection rates from two survey locations with mortality reported from a nearby commercial wind facility. We identified 2,603 L. noctivagans, 1,908 L. cinereus, and 6,802 L. borealis calls during 6,153 detector-nights. We found a greater number of significant correlations between sites for silver-haired and hoary bat detection rates than in eastern red bat detection rates. Each species exhibited unique seasonal trends in detections among geographic regions. Previously reported mortality rates of L. noctivagans and L. cinereus from a wind energy facility were positively correlated with detection rates of those species at one of our survey locations within 50 km (r = 0.65, P < 0.001 and r = 0.28, P < 0.01, respectively; in both cases d.f. = 94) and with another location within 100 km (r = 0.44, P < 0.001 and r = 0.28, P < 0.01, respectively; in both cases d.f. = 81). These data indicate that seasonal detection rates of all three species under study reflect their different migratory patterns that may be useful in predicting the timing of mortality events at wind energy facilities.
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