Effects of the Anthropogenic Factor on Bats (Chiroptera: Vespertilionidae) in the Volga Region

Using the example of bats inhabiting the Volga region, the cases in which the anthropogenic factor creates favorable conditions for these animals or significantly reduces their diversity of their fauna are considered. In this context, an opinion concerning the approaches to the conservation of bats is formulated.     

Low roost-site fidelity in pallid bats: associated factors and effect on group stability

Despite potential costs of changing roost or densites, many animals frequently move between roosts or dens. Pallid bats (Antrozous pallidus) change diurnal roost sites frequently and also reportedly have a variety of cooperative social behaviors, many of which are associated with the care of developing offspring. Roost switching is likely to increase the costs of maintaining the group stability expected with social cooperation. Pallid bats roosting in rock crevices in central Oregon were studied with radiotelemetry to (1) examine characteristics of day roosts, (2) determine what ecological factors were correlated with low roost fidelity, and (3) examine the temporal stability of roosting groups of pregnant and lactating bats. Pallid bats changed roosts an average of once every 1.4 days throughout the summer. The bats exhibited seasonal shifts in roost use, occupying roosts behind thin slabs of rock in cool weather and roosts in deep rock crevices in warm weather. Roost switching was not correlated with daily variations in weather conditions or with structural characteristics of the diurnal roosts, although switching may have allowed bats to maintain familiarity with several roosts that vary in microclimate. Roost switching was positively correlated with ectoparasite load. High ectoparasite levels were correlated with lower body weights in lactating females (Fig. 3), suggesting that parasites may be costly to the bats. Roost switching may be a strategy to decrease ectoparasite loads by interrupting the reproductive cycles of those parasites that spend at least part of their life cycle on the walls of the roost. Both pregnant and lactating pallid bats frequently changed their diurnal roost location, but lactating bats tended to travel shorter distances between consecutive roosts. Lactating bats were more likely to continue to associate with particular roostmates despite changes in the location of the diurnal roost (Fig. 4) and were less likely to roost alone. Although the stability of groups of lactating bats was not absolute, evidence supported the prediction that such groups are more cohesive than are those of pregnant bats. Received: 20 June 1995/Accepted after revision: 13 July 1996     

Use of Integrated Modeling to Enhance Estimates of Population Dynamics Obtained from Limited Data

Abstract:  Demographic data of rare and endangered species are often too sparse to estimate vital rates and population size with sufficient precision for understanding population growth and decline. Yet, the combination of different sources of demographic data into one statistical model holds promise. We applied Bayesian integrated population modeling to demographic data from a colony of the endangered greater horseshoe bats (Rhinolophus ferrumequinum) . Available data were the number of subadults and adults emerging from the colony roost at dusk, the number of newborns from 1991 to 2005, and recapture data of subadults and adults from 2004 and 2005. Survival rates did not differ between sexes, and demographic rates remained constant across time. The greater horseshoe bat is a long-lived species with high survival rates (first year: 0.49 [SD 0.06]; adults: 0.91 [SD 0.02]) and low fecundity (0.74 [SD 0.12]). The yearly average population growth was 4.4% (SD 0.1%) and there were 92 (SD 10) adults in the colony in year 2005. Had we analyzed each data set separately, we would not have been able to estimate fecundity, the estimates of survival would have been less precise, and the estimate of population growth biased. Our results demonstrate that integrated models are suitable for obtaining crucial demographic information from limited data.     

Wind farm and fauna interaction: detecting bird and bat wing beats through cyclic motion analysis

Recent Government announcements have implied that wind power will play a major part in providing energy for the UK (BBC 2007 BBC. 2007. Wind ‘could power all UK homes’ [online], British Broadcasting Corporation. Available from: http://news.bbc.co.uk/1/hi/uk_politics/7135930.stm [Accessed 20 January 2008] [Google Scholar]). However, there is much concern that wind farms can have a significant impact on flying fauna (bats and birds) using the area, particularly at night. As part of an Environmental Impact Assessment, thorough appropriate surveys are necessary for quantifying and minimising any risk wind farms may cause flying fauna. Manual surveys that are commonly used are not always cost‐effective, efficient or practical. Remote systems based on motion detection are increasingly being used to monitor wildlife.

Fast‐moving airborne targets such as aeroplanes can falsely trigger motion‐detection based remote systems. As birds and bats repetitively flap their wings, this oscillating motion can be used to distinguish them from other airborne targets. Time periods between wing oscillations are not always constant, and hence the motion is not periodic. A method to detect cyclic motion based on similarity matrices is proposed, and synthetic and real data are used.     

Seasonal spatial differentiation of sex groups in populations of resident bat species (Chiroptera,Vespertilionidae) in the Southern Urals

On the basis of studies on the ecology of boreal bat species in the Southern Urals (1997–2004), the first classification of their summer habitats has been made. It has been shown that spatial segregation of sex groups into areas of two types, designated wintering and breeding zones, takes place in populations in the period of offspring rearing. In females, seasonal migrations are guided by imprinting on sites providing sufficient food for offspring rearing and on wintering sites. In males, imprinting on wintering sites alone is observed.     

Trace metal concentrations in hairs of three bat species from an urbanized area in Germany

Metal-contaminated soils and sediments are widespread in urbanized areas due to atmospheric deposition close to emission sources. These metals are bio-available for organisms, e.g., insects, and accumulate in food chains of insectivorous mammals. Especially bats, which live in urban regions and ingest large amounts of food relative to their body mass, are at risk of being poisoned due to the accumulation of trace metals. To determine species-specific trace metal contents in bats from urban environments, hair samples were analyzed by ICP-OES. Observed trace metal concentrations were related to species-specific foraging habitat, prey spectrum and degree of synanthropy. The species studied were Pipistrellus pipistrellus, Myotis daubentonii and Nyctalus noctula. P. pipistrellus showed the highest concentrations of lead and zinc and slightly higher concentrations of cadmium than the other two species, which was related to its high degree of synanthropy with foraging habitat mostly located in cities. In contrast, N. noctula displayed the highest contents of manganese and copper. The reason might be found in its prey spectrum, as N. noctula feeds mainly on beetles that are caught in cultured areas. Trace metal concentrations determined in hair samples of M. daubentonii ranged between the values of P. pipistrellus and N. noctula, probably reflecting an intermediate level of synanthropy. Positive correlations were observed between the concentrations of cadmium and lead and those of manganese and copper. Hair samples from bats are suitable monitoring tools to study trace metal exposure and can be used to determine differences in trace metal levels between species.     

Specific features of distribution of resident bat species (chiroptera: Vespertilionidae) in the eastern East European plain and adjacent regions

Some specific features of the distribution of resident Chiroptera (10 forms) in the eastern East European Plain and adjacent areas (44°–65° N, 40°–60° E) are described. It is noted that in different seasons of the year,Myotis dasycneme, M. daubentonii, M. nattereri, M. mystacinus, M. brandtii, Plecotus auritus, Eptesicus nilssoni, andE. serotinus serotinus are found more often in upland areas with karst and other erosional forms of relief, whereasE. serotinus turcomanus andPipistrellus kuhlii display no preference for these types of relief.     

Unexplored Diversity and Conservation Potential of Neotropical Hot Caves

The term hot cave is used to describe some subterranean chambers in the Neotropics that are characterized by constantly high ambient temperatures generated by the body heat of high densities of certain bat species. Many of these species have limited geographic ranges, and some occur only in the hot‐cave environment. In addition to the bats, the stable microclimate and abundant bat guano provides refuge and food for a high diversity of invertebrates. Hot caves have so far been described in the Caribbean and in a few isolated locations from Mexico to Brazil, although there is some evidence that similar caves may be present throughout the tropics. The existing literature suggests these poorly known ecosystems, with their unique combination of geomorphology and bat‐generated microclimate, are particularly sensitive to disturbance and face multiple threats from urbanization, agricultural development, mining, and tourism. Diversidad No Explorada y Potencial de Conservación de Cuevas Neotropicales Calientes     

Effects of Artificial Roosts for Frugivorous Bats on Seed Dispersal in a Neotropical Forest Pasture Mosaic

Abstract:  In the Neotropics ongoing deforestation is producing open and heavily fragmented landscapes dominated by agriculture, mostly plantations and cattle pastures. After some time agriculture often becomes uneconomical and land is abandoned. Subsequent habitat regeneration may be slow because seed inputs are restricted by a lack of incentives—such as suitable roost sites—for seed dispersers to enter deforested areas. Increasing environmental awareness has fostered growing efforts to promote reforestation. Practical and cost-efficient methods for kick-starting forest regeneration are, however, lacking. We investigated whether artificial bat roosts for frugivorous bat species can attract these key seed dispersers to deforested areas, thereby increasing seed rain. We installed artificial bat roosts in a forest-pasture mosaic in the Costa Rican Atlantic lowlands and monitored bat colonization and seed dispersal. Colonization occurred within a few weeks of installation, and 10 species of bats occupied the artificial roosts. Five species of frugivorous or nectarivorous bats colonized artificial roosts permanently in both primary habitat and in deforested areas, in numbers similar to those found in natural roosts. Seed input around artificial roosts increased significantly. Sixty-nine different seed types, mostly of early-successional plant species, were transported by bats to artificial roosts in disturbed habitats. The installation of artificial bat roosts thus successfully attracted frugivorous bats and increased seed inputs into degraded sites. This method is likely to speed up early-vegetation succession, which in turn will attract additional seed dispersers, such as birds, and provide a microhabitat for seeds of mid- and late-successional plants. As well as supporting natural forest regeneration and bat conservation, this cost-efficient method can also increase environmental awareness among landowners.     

Variation in Physiological Stress between Bridge‐ and Cave‐Roosting Brazilian Free‐Tailed Bats

Abstract: Since the late 1980s, Brazilian free‐tailed bats (Tadarida brasiliensis) have increasingly used bridges as roosts in the southern United States. We examined differences in blood cortisol levels, body condition, and parasite load, as measures of physiological stress in bats roosting in bridges and bats roosting in caves. We collected data during three periods, coinciding with female phases of reproduction. For all measures, bats were captured during the nightly emergence from the roost and immediately sampled. Cortisol levels were significantly higher during pregnancy and lactation and in individuals with lower body‐condition scores (length of forearm to mass ratio) and significantly higher in bats roosting in caves than in those roosting in bridges. Thus, we concluded that individuals of this species that roost in bridges are not chronically stressed and seem to be unaffected by human activities present at bridges. This is a rare documented instance where a human‐dominated environment does not appear to be adversely affecting the physiological health of a free‐ranging animal.