Ábrahám Levente: Biomonitoring a Dráva folyó magyarországi szakasza mentén 2000-2004 - Natura Somogyiensis 7. (Kaposvár, 2005)
Dombi, Imre: Bat monitoring along the Drava River (Mammalia: Chiroptera) - Denevér-monitoring a Dráva mentén (Mammalia: Chiroptera)
144 MATURA SOMOGYIENSIS - true representation of the bigger range and characteristic habitats based on the features, characteristics and size of the chosen area. - easy accessibility, secure identification on map Four sample areas were chosen, respectively: - Őrtilos - Drava bank, floodplain areas South fromme railway station, gravel-pit lake - Gyékényes - Lankóci forest, old oak forests, Berek and surroundings - Vízvár - Drava bank, part of bank under me village and the settlement - Babócsa - Mérus forest and the backwater of Drava at Babócsa According to different sampling methods more types of sampling areas were chosen. Consequently, there are point count and linear sampling areas. Sampling methods Basically, four methods were applied. The first one was capturing bats, identifying them in hand, thus data collection. The second one was without actually capturing the animals, only observing them on their hunting area using bat-detectors. The third method was finding the building-dwelling colonies in their roost-sites and other observations. All of these methods are among those suggested by MBmR, but adaptation to local conditions was necessary. 1. Capturing bats with net The point is to put up nets in the appropriate areas, where bats are most likely to fly through during the night and thus captured. Then identification of the species and data collection, such as age, sex, forearm length (FA), body mass, time of capturing, and net number are recorded. If the animal is ringed, the ring number is also written down. Moreover, additional data can be: condition of breasts concerning sucking, turgidity of testicles, former scars, other individual characteristics, amount of parasites on body, in case of long-eared bats (Plecotus sp.) length of thumb and claws, width of ear-cap. Capture circumstances are always recorded as follows: time of capture, weather condition, net position, temperature and humidity per hour. Advantages: precise identification of species, and with the help of age and sex, further data can be gained on reproduction conditions. During the project 6x3 and 12x3 meters, Polish 70/2 thread quality nets were used. 2. Observations with bat-detectors It is a method demanding high technical and professional knowledge. It is based on the reception and transformation of the ultrasound sent out by bats. Differences of echolocation calls among species allow identification and counting of individuals. Advantage: mobility, so that observation is not restricted to a given area, also bats flying in the surroundings are easily and with a great probability detectable. Therefore this method supplies more data, than capturing, identification to species cannot always be achieved in the field, but by recording the sound it can be analysed later on the computer. By all means it is suitable for measuring the intensity of bat-movement, and their relative frequency. It is also apt to observe the different usage of each habitat-type. The detector is used in two methods: Point &МШЙ. sampling with bat-detector: at waterside, sampling on one spot, monitoring Шшйшйши'ж bat (Myotis daubentoni) and pond bat (Myotis dasycnemé). Line transect sampling: observation is accomplished along a pre-determined line. Equipment used during the .-monitoring from 2001 : Pettersson D240X bat-detector and Sony WMD6C tape recorder. Sound-recordings are analysed using Cool 2000 software.
