München, Univ., Diss., 2001. / Computerdatei im Fernzugriff.

München, Univ., Diss., 2001. / Computerdatei im Fernzugriff.

University, Diss., 2001--München.

Studies involving geographic variation in the phenotypes of bats help scientists to explain why these mammals are the most species rich mammalian order second only to rodents, with well more than 1 300 species occurring worldwide. Such species richness or high diversity is the manifestation of the generation of biodiversity through the splitting of lineages within bat species. A lineage of bat species can diversify into several lineages which then differentiate from each other in allopatry. Thus, the spatial separation of a lineage into several lineages could be attributed to geographical, ecological and environmental factors across the distributional range of the species. Similarly, vicariant events may also play a role in separating lineages within species. The Damara horseshoe bat species, Rhinolophus damarensis, is widely distributed but restricted to the western half of southern Africa, where it occurs across several major biomes. Formerly regarded as the subspecies, R. darlingi damarensis, it was elevated to full species status on the basis of genetic and phenotypic differences between it and R. darlingi darlingi. Rhinolophus damarensis is itself made up of two ecologically separated genetic lineages. A total of 106 individuals of R. damarensis were sampled from seven localities across its distributional range, with a view to determining and documenting the extent of geographic variation in body size, echolocation parameters, wing parameters, cranial shape and postcranial morphology of individuals from populations of R. damarensis across the distributional range of the species. Firstly, an investigation into geographic variation in resting echolocation frequency (RF) of the horseshoe bat species, R. damarensis was carried out in the western half of southern Africa (Chapter 2). Three hypotheses were tested. The first one, James’Rule (JR), states that individuals occurring in hot humid environments generally have smaller body sizes than conspecifics that occur in cooler, dryer environments, and the largest are expected to occur in cool, dry areas. On this basis and because of the known relationship between body size and RF, it was predicted that there should be a correlation between body size and climatic factors and between body size and RF. The second hypothesis was Isolation by Environment (IbE) mediated through sensory drive, which proposes that diversification of lineage may be driven by environmentally-mediated differences in sensory systems. Under this hypothesis, it was predicted that call frequency variation should be correlated with climatic variables. The third hypothesis was that Isolation by Distance (IbD) can influence phenotypic trait variation by restricting gene flow between populations. Under the Isolation by Distance (IbD) Hypothesis, it was predicted that call frequency variation should be partitioned in accordance with geographic distance between populations. To investigate the probability of the JR, IbE and IbD, the Akaike’s information criterion AICc candidate models were evaluated with different combinations of environmental (annual mean temperature and relative humidity), spatial (latitude and region) and biological (forearm as a proxy for body size) predictor variables to determine their influence on resting frequency (RF) across the distributional range of R. damarensis. Linear mixed effects models (LMEs) were employed to analyse the relationship between the response variable (RF) and the environmental, spatial and biological predictor variables. The influence of prey detection range and atmospheric attenuation was also investigated. The results showed no evidence for JR or for random genetic drift. Body size was neither correlated with RF nor environmental variables, suggesting that variation in RF was not the result of concomitant variation in body size as proposed by JR. Similarly, the Mantel test showed no IbD effect and there was therefore no evidence that genetic drift was responsible for the variation in RFs. In contrast, the LMEs showed that there was support for IbE in the form of an association between RF and region (in the form of the variable “Reg”) which was based on the two geographically separated genetic lineages. Furthermore, RF variation was also associated with the climatic variable AMT. The taxonomic status of R. damarensis was investigated using ecological traits and phenotypic characters including skulls, wings and echolocation (Chapter 3) and three dimensional (3D) scanned skulls and mandibles (Chapter 4). The main objective (Chapter 3 and Chapter 4) was to test whether previously reported genetic divergence between the two R. damarensis lineages was associated with phenotypic divergence. Morphometric and echolocation measurements were taken from hand held individual bats in the field, and skull measurements were taken from field collected voucher specimens as well as museum specimens. Discriminant Function Analyses (DFA) revealed that there was geographic variation among populations and lineages of R. damarensis. Multivariate Linear Regressions (MLV) and Linear models (LM) on the basal parts of bacula revealed significant differences between the southern and northern lineages of R. damarenis. The bacula of the two lineages of R. damarensis appear to have different shapes. Diversification through shape analyses (Chapter 4) was investigated using three dimensional (3D) geometric morphometric analyses based on X-ray microcomputed tomography (µCT) scanning of dried skulls and mandibles of R. damarensis. Procrustes Anova results of both mandibles and skulls indicated that there were no significant differences between sexes but that the shape of skulls and mandibles varied across different localities (Chapter 4). Canonical Variate Analysis (CVA) suggested that geographic variation in R. damarensis mandibles was based on the shape and thickness of the alveolar bone. Geographic variation in the skulls was based on changes in the rostrum, anterior medial swelling and brain case. Some populations had slightly deeper rostra, slightly larger anterior medial swellings and smaller braincases, whilst others had slightly shallower rostra, slightly smaller anterior medial swellings and larger braincases. The northern lineage was found to be separated from the southern lineage based on the changes in skull and mandible shape. Therefore, separation of lineages within R. damarensis (Chapter 4) could be associated with the foraging and feeding behaviour of the species under different ecological conditions due to ecological opportunity. Overall, differences in the RF were found to be associated with Isolation by Environment mediated through sensory drive and this has led to the formation of two regional (northern and southern) groupings in RF (Chapter 2). The two lineages were supported by both the phenotypic divergence (Chapter 3) and shape variation within R. damarensis skulls and mandibles (Chapter 4). Thus, phenotypic differences corresponded to genetic differences between the two lineages and provide support for IbE.

Mettre en place des mesures de protection efficaces contre la dégradation et la fragmentation de l'habitat d'une espèce nécessite d'être capable de comprendre l'impact de l'environnement sur sa dynamique de population ainsi que sa sensibilité à la perte de connectivité entre les populations. Obtenir ces informations est déjà un défi en soi, qui se complique encore pour les espèces trop sensibles au dérangement pour être suivies de manière classique. Lors de ce travail, nous avons étudié la dynamique et la génétique des populations d'une chauve-souris forestière qui a subi un très fort déclin dans le nord de l'Europe, le Petit rhinolophe (Rhinolophus hipposideros), à l'aide de méthodes non-invasives (comptages, génétique non-invasive).Nos résultats ont montré que le climat et le paysage autour des colonies de maternités influence la taille et la dynamique des populations du Petit rhinolophe. Nous avons également confirmé un impact direct du paysage sur la survie des juvéniles. Enfin, nous avons observé que la diversité génétique des populations pouvait être fortement diminuée par leurs histoires démographiques et par un manque de connectivité entre les populations. Ces résultats ont des implications directes pour la conservation du Petit rhinolophe mais aussi pour le développement des analyses intégrant des données de génétique non-invasive pour la biologie de la conservation. / Efficient conservation management against habitat degradation and fragmentation of a species requires understanding how the environment impacts its population dynamics and the species’ sensitivity to connectivity loss. Acquiring sufficient knowledge about these processes is challenging for any species, and is even more complicated for species too sensitive to be studied with classical methods. During this work, we studied the population dynamics and genetics of a woodland specialized bat who has undergone a serious decline in the north of Europe, the lesser horseshoe bat (Rhinolophus hipposideros), with non-invasive methods (counts, non-invasive genetics).Our results shown that climate and landscape around maternity colonies explain population size variations and dynamics of the lesser horseshoe bat. We also confirmed a direct impact of landscape on juvenile survival. We finally observed that genetic diversity could be strongly decreased by population history and a lack of connectivity between populations. Our results have direct implications for the lesser horseshoe bat conservation but also for the development of analyses integrating non-invasive genetic data in conservation biology.

In the pre-lacation, lactation and post-lactation periods in 2010 and 2011 and the pre-lactation period in 2012 we used radio-telemetry to determine changes in home range and habitat activity and preference of the maternity colony of the Mediterranean horseshoe bat (Rhinolophus euryale) in Slovak Karst. The colony roosted in the attic of the monastery in Jasov. This area represents the northern margin of the species distribution range. In total, we tagged 35 females that were radio-tracked for 31 nights. For the all pre- lactation periods 17 females were marked, in the lactation periods 12 females were marked, and 6 females were marked in the post-lactation periods. The females were marked with radiotags and the VHF telemetry (radio telemetry using very high frequencies) was used. We compared the spatial and habitat preferences in the above defined seasons of the annual reproductive cycle. The total number of recorded locations was 858 for all reported periods. We compared the varios aspects of activity of the females during the night in the particular periods. We have shown that the females left their roost in the pre-lactation periods as the most late. These were followed by the females in the lactation periods and as the most early after the sunsetthe roost was left by the females in the...

As human population grows and develops, more urban areas are expanding. Urbanisation has many impacts on the natural environment and one understudied pollutant is artificial light at night. The aims of this thesis were to examine the impacts of street lighting on bats and investigate the exposure of British bat species to artificial light at night and explored the mitigation option of part-night lighting. The current exposure of British bat species to artificial lighting was assessed using roost locations and population sizes from a long-term dataset (1997-2012) from the Bat Conservation Trust’s National Bat Monitoring Programme on seven bat species (Eptesicus serotinus, Myotis nattereri, Pipistrellus pipistrellus, P. pygmaeus, Plecotus auritus, Rhinolophus hipposideros and R. ferrumequinum). These data were combined with satellite imagery in roost sustenance zones and home ranges. Bat roosts were found in areas with brighter light levels than random locations for P. pipistrellus, P. pygmaeus and Plecotus auritus. Species that forage around streetlights (P. pipistrellus and P. pygmaeus) had significantly higher light levels in the landscape around their roosts than species which avoid street lit areas (R. hipposideros, M. nattereri and P. auritus). Colony size was negatively correlated with light levels. This study highlights that different species have different requirements in the landscapes around their roosts. To investigate landscapes effects of artificial light at night on the understudied light avoiding species R. ferrumequinum, eight maternity roosts were surveyed to explore the interaction between habitat features and street lighting. At each maternity roost, bat detectors were deployed at 25 paired street lit and dark locations. Street lighting had a significant negative effect on bat activity. Locations closest to the maternity roost had higher bat activity than those further away and road type had a significant effect on bat activity, with the highest bat activity recorded at minor roads compared with A and B roads. These results highlight the large negative impact street lighting can have on bat activity patterns and the need for mitigation. Several mitigation strategies have been suggested to combat the effects of artificial light at night but few have been tested. One of these suggestions is to restrict the hours of lighting through the night, often called part-night lighting. Part-night lighting has been implemented by many local authorities, often switching the lights off after midnight and switching them back on before dusk. To explore the effects of part night lighting on bats, the hourly patterns of activity for R. ferrumequinum were studied. Bat activity was bimodal, with a peak in the first few hours after sunset followed by a smaller peak before sunrise. To capture more than 50% of bat activity during the dark period of the night, street lights would be required to switch off before 11pm. To explore this further, a before-and-after study of part-night lighting was conducted at towns across Devon. Following the conversion from full-night lighting to part-night lighting, switching street lights off at 2 am, there was a significant reduction in P. pipistrellus and a significant increase for P. pygmaeus and Nyctalus noctule activity. Although part-night lighting is not often operational during peak activity periods for bat species, reducing the duration of lighting at night has impacts on activity patterns for several species. This thesis shows that artificial light at night has impacts on bats across the landscapes around their roosts. Artificial lighting has impacts for species in different ways, depending on whether they forage around street lights or avoid street lit areas. For species that avoid street lit areas such as R. ferrumequinum, street lighting can have very significant negative impacts on the availability of areas around their roosts. This highlights the need for conservation measures to reduce impacts of artificial lighting. Although mitigation schemes such as part-night lighting may help to minimize impacts of nighttime lighting, more tailored schemes for bats should devised to achieve greater conservation impacts.