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 165 The effectiveness of the trapping has been increasing continually since 2001. While in the first whole year we captured a mammal predator about every fourth day (0.2586 captures/ 100 trap nights), till then every second day in 2004 (0.4366 captures/ 100 trap nights). Whereas the increasing of the effectiveness at the present not obviously shows the increasing of the predator species' density, but probably improving the knowledge about trapping and getting to know more about the territory corrected our results (Fig. 6). Conclusions The river Dráva region's rich predator fauna significantly contributes to the territory's extraordinary values. In addition to the three species, which are in the Red Book (RAKONCZAY 1989) -wild cat, otter, golden jackal- most of our protected and fair game predators have breeding populations on the river region. Bearing the nationwide tendency and the adaptation ability of the predator species in mind the decreasing of the narrow-bearing, more sensible species' population while the increasing of the multitudinous species' population can be prognosticated in constant habitat conditions. This means the following in case of the single species. The density of the small sized Mustelids (weasel, ermine, common polecat) depends on the available amount of food sources first of all. Namely if intensive agricultural works don't affect the territory, then their number will range in the next few years particularly together with the rising of the small rodents. We don't expect a changing in the spreading of the generalist and opportunist predators present in large numbers (stone marten, badger, red fox), their stock density conceivably increases onwards. The same could be probable in the case of the golden jackal, although what is happening with it's population's European spreading centre in the Balkans acts as an important and unknown factor. Within constant habitats the stock of the marten and the otter could stay stable, while the wild cat populations can remain expectedly in the most undisturbed areas also free from cats with their characteristic populations nowadays. The sedentation of our large sized predators (wolf, lynx) on the plain Dráva is not probable nor in the next few years, can the permanent appearing of the fauna-strange raccoon dog however be expected. The case is different when significant changes happen in the habitats or in the management along our one of the most beautiful river. Neither the otter, nor the pine marten and especially the wild cat tolerate the disturbance deriving from the human activity, or the changes in habitats as a result of that. In case of the ermine's habitat cessation or decreasing its stock would decrease too, because due to its special habitat needs and to its typical territory usage it might not be able to settle down on new areas. Whereas the further decreasing of the multitudinous species' populations won't significantly depend on the incidental changes. This means, that the predators that get into worse habitat circumstances even have to fight with the competition caused by the species with increasing stock, squarely they will be the losers of it. These last consequences give the value of the predator stock on the strictly protected area situated south from Bélavár and the importance of the monitoring point formed here. The most common predators of the area bordered by the railway from north, by the stream Zsdála from west, by the river Dráva from south, whilst by the abandoned pebble-mine lakes from east are the weasel and the wild cat and the otter has a significant stock too. All these three species belong to those predators, which are narrow-bearing, can hardly tolerate the human proximity or not at all, are hard hit by the changes made