The Bats of Greece: An Updated Review of Their Distribution, Ecology and Conservation.

Bats of Greece have been studied since the second half of the 19th century. Their distribution and ecology, however, remain poorly understood. Conservation efforts for the protection of the roosting and foraging habitats of their populations in Greece are limited. To date, 35 bat species have been recorded from Greece. Four species (Eptesicus anatolicus, Plecotus auritus, Myotis brandtii and Rousettus aegyptiacus) have a limited distribution in the country and the presence of one species (Myotis mystacinus) requires verification. The present study summarises all existing knowledge and adds several hundred new records on the distribution of bats of Greece. Additionally, it provides a summary of new insights on various aspects of their roosting ecology, foraging habitat use, altitudinal distribution, winter activity and landscape characteristics around major roosts. Finally, it discusses the current research and conservation needs of Greek bats.

Year-Round Bat Activity and Species Richness Near Temporary Ponds in the Mediterranean Region.

Mediterranean temporary ponds are recognized as conservation priority habitats that face anthropogenic threats and are important habitats for a number of aquatic and terrestrial animals and plants. Bats are a diverse group of animals that use ponds for drinking and feeding on emerging aquatic insects and terrestrial insects in the riparian zone. We investigated the importance of temporary ponds for bats in Greece by acoustically sampling bat community structures and activity at temporary ponds throughout the year. We sampled monthly, from 3 to 13 months in 2019-2020, at sites at the pond edge and approximately 150-300 m away from the edge, at four temporary ponds in northern and southern Greece. Our results confirm the importance of temporary ponds for bats as activity was recorded year-round and was high in all but the winter months. In general, the distance to the edge of the pond and the presence of water in the pond explained bat activity together with air temperature. Importantly, whether dry or not, all ponds supported bat activity, independent of their particular characteristics. This study highlights the urgent need for the conservation of temporary ponds, especially in areas with limited water availability.

Seasonal bat activity related to insect emergence at three temperate lakes.

Knowledge of aquatic food resources entering terrestrial systems is important for food web studies and conservation planning. Bats, among other terrestrial consumers, often profit from aquatic insect emergence and their activity might be closely related to such events. However, there is a lack of studies which monitor bat activity simultaneously with aquatic insect emergence, especially from lakes. Thus, our aim was to understand the relationship between insect emergence and bat activity, and investigate whether there is a general spatial or seasonal pattern at lakeshores. We assessed whole-night bat activity using acoustic monitoring and caught emerging and aerial flying insects at three different lakes through three seasons. We predicted that insect availability and seasonality explain the variation in bat activity, independent of the lake size and characteristics. Spatial (between lakes) differences of bat activity were stronger than temporal (seasonal) differences. Bat activity did not always correlate to insect emergence, probably because other factors, such as habitat characteristics, or bats' energy requirements, play an important role as well. Aerial flying insects explained bat activity better than the emerged aquatic insects in the lake with lowest insect emergence. Bats were active throughout the night with some activity peaks, and the pattern of their activity also differed among lakes and seasons. Lakes are important habitats for bats, as they support diverse bat communities and activity throughout the night and the year when bats are active. Our study highlights that there are spatial and temporal differences in bat activity and its hourly nocturnal pattern, that should be considered when investigating aquatic-terrestrial interactions or designing conservation and monitoring plans.

Isotopic evidence for dietary niche overlap between barking deer and four-horned antelope in Nepal.

BACKGROUND: Morphologically similar sympatric species may have a high degree of niche overlap. Barking deer Muntiacus vaginalis and four-horned antelope Tetracerus quadricornis are solitary ungulates of the Indian sub-continent. Limited information is available regarding their trophic ecology, particularly of the endemic four-horned antelope. We present stable carbon (δ(13)C), nitrogen (δ(15)N), and sulphur (δ(34)S) isotopic values, and nitrogen content (%N) of faeces from barking deer and four-horned antelope living in lowland Nepal to assess trophic niche differentiation of these herbivores along the browser-grazer continuum. We also describe trophic differences between those two species in ecological niches and seasonal effects on their diets. RESULTS: We found that the barking deer and four-horned antelope consumed C3 plant sources exclusively. The niche partitioning in their diet was reflected by δ(34)S values. Some seasonal effects observed were: δ(13)C and δ(15)N were significantly lower in the dry season diet of four-horned antelope than that of barking deer, while δ(34)S values were significantly higher in the winter diet; monsoon diet was similar for both species. Faecal N levels for barking deer and four-horned antelope were similar throughout all the seasons, indicating that both species adapted their feeding behaviour so as to maximize protein intake, in accordance with season and environment. CONCLUSIONS: Barking deer and four-horned antelope both are browsers; their dietary sources overlapped during monsoon but differed during the dry season. Conservation actions focused on resource management during the dry season to reduce food scarcity and competition over limited resources is likely to be the most effective.

Tracking diet preferences of bats using stable isotope and fatty acid signatures of faeces.

Stable isotope and fatty acid signatures of biomaterials can provide important information about the dietary niche of animals. Stable isotope and fatty acid signatures differ between aquatic and terrestrial food webs, and therefore can be used to assess the aquatic and terrestrial contributions to the diets of species. We studied faecal samples of three co-occurring bat species with known differences in feeding preferences. The aim was to assess whether stable isotope and fatty acid signatures of faeces can be used to determine feeding preferences. We used bat faeces because they can be easily and non-invasively collected. We hypothesised that faeces stable isotope and fatty acid signatures will reveal the terrestrial, aquatic and mixed feeding niches of Myotis myotis, M. daubentonii, and M. mystacinus, respectively. As predicted, the faeces of M. myotis were characterized by higher δ(13)C values and higher concentrations of linoleic acid and total ω6 polyunsaturated fatty acids (PUFAs), which are typically higher in terrestrial food webs. The faeces of M. daubentonii had higher δ(15)Ν values and higher concentrations of docosahexaenoic acid and total ω3 PUFAs, characteristic features of aquatic systems. Myotis mystacinus faeces had intermediate δ(15)Ν values and concentrations of both types of fatty acids. Our results show that analysing stable isotope and/or fatty acid signatures of faeces provides a promising, non-invasive tool to study the feeding ecology of bats and to assess aquatic-terrestrial interactions.

Advantages of using fecal samples for stable isotope analysis in bats: evidence from a triple isotopic experiment.

RATIONALE: Stable isotope analysis in ecological studies is usually conducted on biomaterials, e.g. muscle and blood, that require catching the animals. Feces are rarely used for stable isotope analysis, despite the possibility of non-invasive sampling and short-term responsiveness to dietary changes. This promising method is neglected due to a lack of calibration experiments and unknown diet-feces isotopic difference (Δ(diet-feces)). METHODS: To fill this gap, we simulated trophic changes occurring in nature when animals switch feeding habitats, e.g. by moving from freshwater to terrestrial systems, from cultivated areas to forests or changing distance from marine environments. In a controlled experiment, the diet of two bat species (Myotis myotis, Rhinolophus ferrumequinum) was altered to an isotopically distinct one. We measured stable nitrogen, carbon and the rarely used sulfur isotope in feces, and calculated Δ(diet-feces) values. RESULTS: The feces acquired the new dietary signature within 2-3 h from food ingestion; thus, they are suited for detecting recent and rapid dietary changes. The Δ(diet-feces) (Δ) did not differ between species or diet (overall means ± standard deviation (sd)): Δ(15)N: 1.47 ± 1.51‰, Δ(13)C: -0.11 ± 0.80‰, Δ(34)S: 0.74 ± 1.10‰. Only Δ(15)N for M. myotis was significantly different from zero and only Δ(13) C differed among the days of the experiment. CONCLUSIONS: Fecal stable isotopes can be now further applied in mammalian ecology. This includes a range of applications, such as studying changes in trophic level, resource or habitat use, on a short time-scale. Such information is gaining importance for monitoring rapidly changing ecosystems under anthropogenic influence.

Seasonal variation of fish abundance and biomass in gillnet catches of an East Mediterranean lake: Lake Doirani.

The seasonal variation of fish species composition and abundance in gillnet catches (14-90 mm knot-to-knot) from the Greek part of the transboundary Lake Doirani was studied during the period 2006-2007. A total of 8,419 specimens weighing 182.3 kg and belonging to 9 species were caught. Catch composition differed with season. Thus, Rhodeus meridionalis dominated in terms of NPUE the spring, Perca fluviatilis the summer and Albumus macedonicus the autumn and winter catches. Cyprinids were generally the most abundant, with the cyprinids:percids biomass ratio ranging from 1.7 in summer to 14.8 in winter, supporting the eutrophic character of the lake. Richness and Shannon-Wiener diversity and evenness indices differed seasonally (ANOVA; p < 0.05). The abundance-biomass comparative (ABC) curves showed that fish communities were dominated by one or a few opportunistic species (e.g. Rhodeus meridionalis, Albumus macedonicus), which while dominated in number did not dominate in biomass, being small bodied.