Activity patterns of insectivorous bats during a seasonal transition period from hibernation to reproduction

2020 ◽  
Vol 42 (1) ◽  
pp. 1
Author(s):  
Anna C. Doty ◽  
Leroy Gonsalves ◽  
Bradley S. Law

Bat activity is influenced by fluctuating environmental variables. It may also be influenced by energetic pressures related to pregnancy, lactation, and emergence following winter inactivity. We evaluated nightly changes in relative bat activity at Royal National Park in response to Julian date, ambient temperature, precipitation, wind speed and moon phase on a nightly scale for six weeks during spring, as insectivorous bats move out of hibernation or frequent, prolonged torpor, and into the maternal season. Interestingly, later Julian date (reflecting seasonal transition) was the sole variable that best predicted total nightly activity. In addition, we opportunistically assessed bat activity in response to a severe storm, considered a Category 1 cyclone, resulting in 96.4mm of rain in one night and wind speeds up to 94km h–1. Only one species of bat, Chalinolobus gouldii, was active during the storm, with activity restricted to the latter part of the evening when precipitation had reduced, indicating rapid resumption of activity following severe weather. The results of this research can be used as an indicator of emergence from winter inactivity and highlight activity patterns of bat species in relation to environmental variables to inform timing of monitoring programs, bat surveys, and targeted research.


2004 ◽  
Vol 20 (4) ◽  
pp. 397-407 ◽  
Author(s):  
Christoph F. J. Meyer ◽  
Christian J. Schwarz ◽  
Jakob Fahr

We studied activity patterns and habitat use by insectivorous bats in Comoé National Park, Ivory Coast. Bat foraging activity was quantified along five transects representing three different habitat types using acoustic monitoring and captures with mist nets and harp traps. Aerial insect abundance was assessed using a light trap; in addition shrub and tree arthropods were sampled. Bat activity was significantly and positively related to insect availability and ambient temperature, whereas increased visibility of the moon had a negative influence on flight activity. Together, these factors best explained both total bat activity and activity of bats hunting in open space and edge habitats. The interaction between temperature and light intensity was the best predictor of activity by species foraging in obstacle-rich forest habitats, however, the regression model had a low predictive value. Overall, a large proportion (c. 50%) of the variation in bat activity appeared to be a consequence of transect- and/or habitat-specific influences. We found a significant non-linear relationship between the activity of QCF (quasi-constant frequency) and FM–QCF (frequency modulated – quasi-constant frequency) bats and the phase of the moon, with lowest levels of activity occurring near full moon. We interpret this lunar-phobic behaviour as a reflection of a higher predation risk during moonlit periods. For FM (steep frequency modulated) and CF (constant frequency) bats, no significant correlation was found, although there was a trend suggesting that these bats at least were not negatively affected by bright moonlight. Foraging activity of bats was positively correlated with the abundance of atympanate moths; however, no such correlation was found for tympanate moths.



2019 ◽  
Vol 10 (1) ◽  
pp. 180-195 ◽  
Author(s):  
Michael S. Muthersbaugh ◽  
W. Mark Ford ◽  
Karen E. Powers ◽  
Alexander Silvis

Abstract Many central Appalachian ridges offer high wind potential, making them attractive to future wind-energy development. Understanding seasonal and hourly activity patterns of migratory bat species may help to reduce fatalities at wind-energy facilities and provide guidance for the development of best management practices for bats. To examine hourly migratory bat activity patterns in the fall and spring in Virginia in an exploratory fashion with a suite of general temporal, environmental, and weather variables, we acoustically monitored bat activity on five ridgelines and side slopes from early September through mid-November 2015 and 2016 and from early March through late April 2016 and 2017. On ridges, bat activity decreased through the autumn sample period, but was more variable through the spring sample period. In autumn, migratory bat activity had largely ceased by mid-November. Activity patterns were species specific in both autumn and spring sample periods. Generally, migratory bat activity was negatively associated with hourly wind speeds but positively associated with ambient temperatures. These data provide further evidence that operational mitigation strategies at wind-energy facilities could help protect migratory bat species in the Appalachians; substantially slowing or locking wind turbine blade spin during periods of low wind speeds, often below where electricity is generated, and warm ambient temperatures may minimize mortality during periods of high bat activity.



1998 ◽  
Vol 20 (3) ◽  
pp. 369
Author(s):  
K. Sanderson ◽  
D. Kirkley

Bat activity was surveyed at Belair National Park, Adelaide and an adjacent house in Glenalta, March 1996 to March 1997, using the Anabat system. 44 bats of 6 species (Chalinolobus gouldii, C. morio, Vespadelus darlingtoni, V. regulus, V. vulturnus, and Nyctophilus geoffroyi) were captured, providing positive identification of calls. Three additional species were recorded (Tadarida australis, Mormopterus planiceps and an unidentified species). At Playford Lake, Belair, 2522 bat calls were recorded in 35 h, with most calls from V. darlingtoni (76.3% of total). At Glenalta, 1521 calls were recorded in 238 h, with most calls from C. gouldii (69.2% of total). V. darlingtoni, V. regulus and M. planiceps showed significantly more activity at Playford Lake, Belair, a wooded site beside a lake, than at Glenalta, a suburban site with artificial lighting, while activity of C. gouldii and T. australis was similar at the two sites. Most bats showed significant lower activity in winter, apart from V darlingtoni, which was active all year round at Belair. Nocturnal temperatures during the study varied from 6-31°C. The activity of most bat species showed no significant correlation with temperature, apart from C. gouldii at Belair, which averaged 1.2 passes per hour below 13°C and 9.3 passes per hour above l3°C.



Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 775
Author(s):  
Carlos Esse ◽  
Francisco Correa-Araneda ◽  
Cristian Acuña ◽  
Rodrigo Santander-Massa ◽  
Patricio De Los Ríos-Escalante ◽  
...  

Pilgerodendron uviferum (D. Don) Florin is an endemic, threatened conifer that grows in South America. In the sub-Antarctic territory, one of the most isolated places in the world, some forest patches remain untouched since the last glaciation. In this study, we analyze the tree structure and tree diversity and characterize the environmental conditions where P. uviferum-dominated stands develop within the Magellanic islands in Kawésqar National Park, Chile. An environmental matrix using the databases WorldClim and SoilGrids and local topography variables was used to identify the main environmental variables that explain the P. uviferum-dominated stands. PCA was used to reduce the environmental variables, and PERMANOVA and nMDS were used to evaluate differences among forest communities. The results show that two forest communities are present within the Magellanic islands. Both forest communities share the fact that they can persist over time due to the high water table that limits the competitive effect from other tree species less tolerant to high soil water table and organic matter. Our results contribute to knowledge of the species’ environmental preference and design conservation programs.



Biotropica ◽  
1977 ◽  
Vol 9 (2) ◽  
pp. 73 ◽  
Author(s):  
M. B. Fenton ◽  
N. G. H. Boyle ◽  
T. M. Harrison ◽  
D. J. Oxley




Mammalia ◽  
2016 ◽  
Vol 80 (4) ◽  
Author(s):  
Julia Salvador ◽  
Santiago Espinosa

AbstractOcelots were historically hunted for their skins but habitat loss is now their most serious threat, causing rapid declines in populations throughout their range. Ocelot abundance has been estimated for various locations across the Neotropics, but we still lack this information from some countries, including Ecuador. Knowing whether ocelot abundance is increasing or decreasing is important to assess the conservation status of this species and the conditions of its habitats in the Ecuadorian Amazon and in the region. To determine whether ocelot abundance and its behavior are affected by human-related activities, camera-trap surveys were carried out in two localities of Yasuní National Park (YNP), one that has experienced hunting, oil extraction, and roads (Maxus Road) and one that is largely unaffected by these activities (Lorocachi). During the survey, 35 and 36 individual ocelots were photographed in Maxus Road and Lorocachi, respectively. Population density estimates were similar for both localities, ranging from 0.31 (SE±6) to 0.85 (SE±17) ocelots/km



2013 ◽  
Vol 141 (5) ◽  
pp. 1648-1672 ◽  
Author(s):  
Kelly M. Keene ◽  
Russ S. Schumacher

Abstract The accurate prediction of warm-season convective systems and the heavy rainfall and severe weather associated with them remains a challenge for numerical weather prediction models. This study looks at a circumstance in which quasi-stationary convection forms perpendicular to, and above the cold-pool behind strong bow echoes. The authors refer to this phenomenon as a “bow and arrow” because on radar imagery the two convective lines resemble an archer’s bow and arrow. The “arrow” can produce heavy rainfall and severe weather, extending over hundreds of kilometers. These events are challenging to forecast because they require an accurate forecast of earlier convection and the effects of that convection on the environment. In this study, basic characteristics of 14 events are documented, and observations of 4 events are presented to identify common environmental conditions prior to the development of the back-building convection. Simulations of three cases using the Weather Research and Forecasting Model (WRF) are analyzed in an attempt to understand the mechanisms responsible for initiating and maintaining the convective line. In each case, strong southwesterly flow (inducing warm air advection and gradual isentropic lifting), in addition to directional and speed convergence into the convective arrow appear to contribute to initiation of convection. The linear orientation of the arrow may be associated with a combination of increased wind speeds and horizontal shear in the arrow region. When these ingredients are combined with thermodynamic instability, there appears to be a greater possibility of formation and maintenance of a convective arrow behind a bow echo.



Author(s):  
Kelly Pearce ◽  
Tom Serfass

Grand Teton National Park is part of the known range of the North American river otter, however not much is known about this semi-aquatic mammal within the park. The results presented here are part of a larger project to investigate the potential of the river otter (Lontra canadensis) to serve as an aquatic flagship (species that engender public support and action) for the Greater Yellowstone Ecosystem. River otters, known for their charismatic behavior have the potential to serve as an aquatic flagship species to promote conservation of aquatic ecosystems. The primary objective of this portion of the study was to identify river otter latrines on portions of the Snake River, between Flagg Ranch and Jackson Lake, and between Jackson Lake Dam and Pacific Creek, collect river otter scats to determine diet of the river otter, and employ remote cameras to determine activity patterns of the river otters. Between 20 June and 1 July 2015, 26 river otter latrines were identified during shoreline surveys, 186 river otter scats were collected, and cameras were deployed at 6 latrines between 7 July and 24 August 2015. River otter scats have been cleaned and prepared for analysis, but have not all been processed to date. Camera traps recorded 222 images, of which 7% (n = 14) were of carnivores, 70% (n = 155) were of non-carnivore mammals, and 9% (n = 22) were of birds. River otters were detected at 1 of the 6 latrines, a total of 5 independent times during the study.



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