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

Ábrahám, Levente.: Biomonitoring of the butterfly fauna in the Drava region (Lepidoptera: Diurna) - Nappali lepkék biomonitoring vizsgálata a Dráva mentén (Lepidoptera: Diurna)

64 NATURA SOMOGYIENSIS Thus in the year of 2000, a new phase of lepidopterolgical investigations commenced on the Hungarian side of the River Drava with a biomonitoring survey that is to decrease the possible environmental impacts of the planned power station. Besides researching the diurnal butterfly fauna, the biomonitoring survey covered the moth fauna as well as other referential groups of insects and vertebrates. The research work on the butterfly fauna, started in 2000, was designed upon the general ecological concept of population stability. From this point of view, the diurnal butterfly populations, regardless of the natural fluctuation of population, do not show remarkable variability: they can be considered stable. The construction and operation of the planned hydroelectric power station will cause a disturbance in the wetlands alongside the River Drava and consequently induce changes in the size of the examined populations. After a resilient period, the populations will establish a steady fluctuation of an average population size at a certain resilience level. The main aim of the biomonitoring researches is to keep track of the changes of the Lepidoptera fauna and, at the same time, to provide information that helps to mitigate the negative effects of the oncoming environmental damages. Material and method In the course of the butterfly fauna research, the to-be-monitored species were specified in accordance with the recommendation of the Hungarian National Biomonitoring System (NBmR). The monitored species were chosen so as they represent different habitats along the River Drava (along a hydroecological gradient) and also sensitive to environmental changes. (Fig. 1.) Fig. 1.: The investigated species in the different habitats