Biology session

Due to the habitat fragmentation and the structural changes in the landscapes caused by human activity, more and more various habitat edges are created. These edges act as an ecological corridor between habitats, and usually preferred by predators. Thus, it is important to study the level of predation in these edges, and to what distance is its effect present. We measured this effect by the predation on artificial nests. Examining the predation of nests has a great role in nature protection, and in the studying of avian reproduction. The identifying of a specific predator of a species can be of much help in the effective protection of that species.

My study was made on the Heves plane Environmentally Sensitive Area, in may, 2008, in order to compare the predations on agricultural areas of different cultivation, and the effect on it by the distance measured from the border. I measured such local factors as the height and density of the vegetation. I worked on three types of cultivation: grassland, fallow, and autumn-sown wheat. The areas had four transects, and nests containing two eggs (one of a quail, and one made of plasticine) were placed in the distance of 0, 10, 25, 50 and 100 meters from the edge along the transect. The nests were inspected one and two weeks after they were placed. From the 180 nests, 82 were predated upon. Sixty-seven prcent of the nests placed in the edes were predated, however at the distance of 100 meters only 28% were predated. This difference proved to be significant after being tested by binominal linear models. The greatest predation was in wheat, and the least nests were destroyed on the fallow, so the difference in cultivation is also significant in terms of the level of predation. Density and height of the vegetation was estimated in a 50 cm radius circle around the artificial nests. The average density and average height was greater around the unpredated nests. Both variables have significantly negative effect on predation

According to our results it appears that the activity of predators is higher near the edge, which indirectly proves their role as an ecological corridor. The edge-effect can be seen even at 50 meters away from the border in wheat, whereas in case of grassland, the predation is restricted to the borders of the area. These differences show the uneven level of disturbance in these areas. The results suggest that both the structure of the landscape and of the vegetation has an effect on nest-predation