Ábrahám Levente: Biomonitoring a Dráva folyó magyarországi szakasza mentén 2000-2004 - Natura Somogyiensis 7. (Kaposvár, 2005)

Heltai, Miklós, Szemethy, László, Szabó, László - Szőcs, Emese: Small and medium sized predators monitoring along River Dráva - Kis- és közepesméretű ragadozó emlősök monitoringja a Dráva mentén

HELTAI M., SZEMETHY L., SZABÓ L., SZŐCS Е.: PREDATOR MONITORING 161 intensive, continuous trapping for three weeks. The traps were set along appointed transects in every 50 meters, the lure was the same within one transect. We kept changing eggs, fish and cattle-liver as baits. The applied traps were 70 cm long and had a 15 x 15 cm door-size. It is suitable for catching small sized of a mustelids kind first of all. The trap is classed among the tip over-doored traps, and it's locking device follows one of the most conventional solutions, it's rodded. The door, made of sheet-iron, and counterweighted at the back side turns up inside the trap. The rod that sets out from the tread-pedal situated at the end of the trap and troppling in the middle shores it up here. When the animal steps onto the pedal the rod is pulled out under the door, that falls down and slips through the steelspring which prevents it of being opened again and is situated at the bottom of the trap. The trap can be handled at it's back side. This side can be opened by removing a screw: on the one hand the lure can be put in here onto the prepared hook, on the other hand in case of a capture the caught animal can be get out here. After identifying the specie, and the sex of the caught animals and the classification into age-groups is done, we signed them with a fur paint used in the animal-husbandry and we released them at the place where they were captured. The fur paint means minimal disturbance for the animal and provides the recapture controlling during a trapping campaign. The processing of the trapping's data was based partly on the number of captured individuals' species -that is the measurable diversity among predator species- partly on the trapping effectiveness - that is the frequency of the predator species. We defined the effectiveness by the number of captures relating to a 100 trap-night. Changes in the trapping protocol The first two years of the program (1999 and 2000) was about the continuous refinement of the trapping method. The final method was worked out till the end of 2000, so that's why we have been publishing data from the results just from then. The changes were necessary because of the inadequate efficiency of the trapping. Changes in the trapping periods The summer trappings were totally unsuccess virtually. The primary reason for this was the extreme swelter of summer's forepart in the past few years. Partly, in the extraordinary warmness the lure went wrong almost immediately and lost all it's attractiveness. The unusual inactiveness of the predator species was also because of the weather. There has been a hybrid-maize seed production with watering for years on the agricultural fields (on meadow Suli) within the indicated area, significantly disturbing the territory and contributing to the unsuccessful. Because of these combined effects we stopped the trappings in the summer, while during the autumnal (October-November) and the end of the winter (February-March) periods we made a 6-6 weeks long continuous trapping after one-one week accustoming, so the yearly whole term of the trapping extended from 9 weeks to 12. Changes in the outplacement and in the lure It was proved in the course of the first two years that the uniform trap placing, worked out for small rodents can't be used in the case of the predator species. The reason for this is that the mammal predators show territorial behaviour generally in one or the whole part of the year and the size of the habitats used by them can be considered relatively large. That's why it was necessary to make an alteration in the originally planned outplacing method. We had been trying to find inside the indicated area the most suitable