Travaux du Muséum National d’Histoire Naturelle © 30 Juin Vol. LIV (1) pp. 223–242 «Grigore Antipa» 2011 DOI: 10.2478/v10191-011-0014-2 THE USE BY BATS (CHIROPTERA: VESPERTILIONIDAE) OF VARIOUS HABITAT TYPES IN MOLDOVA AND THE DANUBE DELTA (ROMANIA) IRINA POCORA, VIOREL POCORA Abstract. Our investigations were carried out in Moldova and the Danube Delta areas during summer periods of 2006-2010. The habitat types which were investigated were: 23 humid areas, 13 woodlands, 7 settlements – streetlamps, 25 car transects. Woodlands and humid areas are the most important habitat types to the majority of bat species, whereas the habitats along roads (mostly made in open areas) are less important. Pipistrellus kuhlii and Nyctalus noctula, also Eptesicus serotinus, Nyctalus leisleri and Vespertilio murinus proved generalists in using foraging habitats, these species being most frequently recorded. In the humid areas, Nyctalus noctula (25.2%), Myotis sp. (24%) and Pipistrellus nathusii/Pipistrellus kuhlii (22.3%) are the most abundant species. In the woodlands, Nyctalus noctula is the most abundant species (19.5%), followed by Pipistrellus nathusii/Pipistrellus kuhlii (17.6%) and Myotis sp. (11.2%). Along the roads, Nyctalus noctula (44%) and Eptesicus serotinus (13.2%) are the most abundant species. At the streetlamps, Nyctalus noctula (45.4%) and Nyctalus leisleri (12.8%) are the most abundant species. In the settlements, Pipistrellus kuhlii (26%) and Nyctalus noctula (23%) are the most abundant species. Résumé. Nos recherches ont été déroulées en Moldavie et dans le Delta du Danube durant la période de la saison chaude, de 2006 à 2010. Les types d’habitats qui ont été étudiés sont: 23 zones humides, 13 forêts, 7 localités - les pôles de lumière, 25 transects en voiture. Les forêts et les zones humides sont les plus importants habitats pour la plupart des espèces de chauves-souris, tandis que les habitats le long des routes (principalement représentées par des zones ouvertes) sont moins importants. Les espèces Pipistrellus kuhlii et Nyctalus noctula mais aussi Eptesicus serotinus, Nyctalus leisleri et Vespertilio murinus sont généralistes en utilisation des habitats d’alimentation, donc elles sont les espèces plus fréquemment signalées. Dans les zones humides Nyctalus noctula (25,2%), Myotis sp. (24%) et Pipistrellus nathusii/Pipistrellus kuhlii (22,3%) sont les espèces les plus abondantes. Dans les habitats forestiers, l’espèce la plus abondante est Nyctalus noctula (19,5%), suivie par Pipistrellus nathusii/Pipistrellus kuhlii (17,6%) et Myotis sp. (11,2%). Le long des routes, les espèces les plus abondantes sont Nyctalus noctula (44%) et Eptesicus serotinus (13,2%). Près des pôles de lumière Nyctalus noctula (45,4%) et Nyctalus leisleri (12,8%) sont les espèces les plus abondantes. Dans les localités, les espèces les plus abondantes sont Pipistrellus kuhlii (26%) et Nyctalus noctula (23%). Key words: bats, habitat use, summer period, echolocation, ecology. INTRODUCTION It is essential to identify the habitat types and characteristics preferred by bat species to define appropriate conservation guidelines and to apply effective protection measures. Habitat selection is one of the principal components of the species ecology, which permits species to coexist (Rosenzweig, 1981). Little is known regarding the degree of habitat specialization in bats, but it is largely presumed that most insectivorous species are habitat generalists and feed opportunistically as prey are observed (Altringham, 1996). However there is some evidence suggesting preferences for some available types of habitat over others (Sherwin et al., 2000). Forests are the most important foraging habitats for bats (Cel’uch & Kropil, 2008). Forests and other woodland habitats positively affect 224 IRINA POCORA, VIOREL POCORA foraging activity and roost availability for many species of bats (Myotis sp.) (Jaberg & Guisan, 2001). The importance of riparian foraging habitats, observed by us confirms findings for other geographical areas (Vaughan et al., 1996; Mickevièiene & Mickevièinus, 2001; Jaberg & Guisan, 2001; Russo & Jones, 2003). Romania is an area of high bat species diversity, being identified 31 bat species so far. Such high number of species makes the acoustic identification of bats in flight an especially challenging task. 26 of the 31 bat species in Romania are considered critically endangered, endangered or vulnerable (Botnariuc & Tatole, 2005). Data concerning the bat populations present in Romania are few and they are referring especially to the bat populations from caves and less to those from buildings. Most of the forests from Romania were cut, regenerating forests probably will never resemble with those that have been cut, and old pieces that were left are small and isolated. Landscapes, in which these fragments of ancient forest remain, differ remarkable from the original conditions, that their value as habitat for many species of wild animals, including bats, is unknown. By the '70s, aquatic wetland areas in eastern Romania were part of a huge wetland consisting of lakes and estuary hook, whose rivers once regularly flooded them with melting snow. By the '70s, planning of the rivers of eastern Romania began in order to stop flooding and obtain new areas for intensive agriculture. Therefore many dam lakes have been built. Gravel beds have been studded by a network of drainage channels. All the meadow and riparian forests have been cleared and poplar and willow plantations were created, in areas between dam and river. Most lawns have been cleared (Ion, 2007). The fragmentation of the forests, reduction of humid area surfaces, agricultural intensification and other man made activities, the lack of connection elements (bushes, rows of trees, isolated trees) from the habitats preferred by bats, make the area of Moldova to be the area with the lowest diversity of chiropterofauna of the country. In our study, a large number of endangered or vulnerable species featured in riparian habitats and broadleaved woodlands, these habitats constituting an important target for conservation. The forested areas limited by humid areas and connection elements between habitats (rows of trees, bushes) are key habitats for bats. The aim of this study was to identify the exploitation of foraging habitats by bats in the Danube Delta and Moldova areas (Romania) as revealed by acoustic surveys. This is the first study on bat habitat use ever conducted in the region. From this study, it is obvious that key habitats play an important role for bat populations and that more information on habitat selection is needed to improve the conservation of bats. MATERIAL AND METHODS Study sites The investigations have performed in fifty-five sites, situated in the Danube Delta and Moldova areas. We investigated the following 4 habitat types: 1) 23 humid areas (4 channels near Letea: Letea channel, Sulina-Letea channel, Magearu channel, Sulimanca channel – near Merhei lake; Sulina and Busurca channels; Gârla Turceascã/Serenea (Sfântu Gheorghe) channel and Rãdãcinoasele channel (Chilia Veche) – the Danube Delta; Brateº channel (GL), Danube River (GL), Prut (GL), THE USE BY BATS OF VARIOUS HABITAT TYPES IN MOLDOVA AND THE DANUBE DELTA 225 Bahlui (IS) and Siret (IS) rivers, Pruteþul Bãlãtãu (IS), Roºu (NT), Roºcani (VS) and Puºcaºi (VS) lakes, fish-breeding farms Larga Jijia (IS), Iezãr – Dorohoi (BT) and Cârja (VS) - Moldova), the width of water flows varied from 7 m to 150 m; 2) 13 woodlands (Letea Forest – the Danube Delta; woodland areas near the Danube river (GL), Prut (GL), Siret (GL and IS), Bãlãtãu (IS); Fãlciu (VS); Bicaz Gorges (NT), Vânãtori-Neamþ Natural Park (NT); Roºcani (IS), Lunca Mirceºti (IS) and Bãdeana (VS) forests, Bârlad’s park (VS), Botanical Garden of Iaºi (IS) - Moldova), if more than 50% of the territory surveyed with a detector was overgrown with trees; 3) 7 settlements – streetlamps (Letea and Chilia villages, Sulina town – the Danube Delta; Secu Monastery (NT), Iaºi town, Deleni, Crâng and Viiºoara (VS) villages - Moldova) and 4) 25 car surveys along roads (mostly in open habitat). The importance of habitat types to bats was estimated not only according to the differences of the frequency of each species within them but also according to the mean number of the passes of the detected species. Abbreviations County names: BT – Botoºani, GL – Galaþi, IS – Iaºi, NT – Neamþ, TL – Tulcea, VS – Vaslui. Sampling design and sound recording We conducted sampling from 2006 to 2010, from March to September. The records were made based on transects and in fixed points. In some habitats there were made only transects, in others before or after transect there were made records in fixed points. At the feeding places on the water bodies, at streetlamps, there were made records only from fixed points. Transects had the length of 1-2 km, and were made in semi-opened habitats (forest border, forest road) and opened habitats (glades, outside the forest, settlements, channels, rivers, lakes); excepting those made on the roads using a slowly going car (25 km/h), for one hour. In 6 sites (channels from Danube Delta and near Galaþi) transects were covered by boat. The medium speed of transects made on foot was of 3.8-4 km/h and of 4.5-5 km/h in those by the boat. Transects were started 30-40 min immediately after the sunset (or after 50-60 min at the feeding places). The records from fixed points and from transects were of about 20 min, excepting those along roads, of one hour. 64 hours of records were analyzed. The number of bat passes recorded in each site was used as an indication of bat activity. A bat pass is the continuous string of echolocation calls heard on a bat detector as a bat flies within range (Vaughan et al., 1996). When recording, we minimized the use of lights to avoid any interference with bat activity (Russo & Jones, 2003). Intensive population surveys of bats are difficult to conduct because of their nocturnal behavior, their wide home range and the problems related to species identification in flight (Jaberg & Guisan, 2001).