Structure and size of a threatened population of the False Ringlet Coenonympha oedippus (Fabricius, 1787) (Lepidoptera: Nymphalidae) in Hungary

Butterfl ies react sensitively to changes in habitat quality. Their diversity has been decreasing in Europe due to habitat degradation, fragmentation, management changes and climate change. The False Ringlet (Coenonympha oedippus) is one of the 59 butterfl y species protected in Hungary. The species occupies marshy meadows dominated by Molinietum vegetation. Besides drainage, inappropriate management can also deteriorate these habitats. Nowadays the butterfl y remains present in a habitat complex in Hungary, at the north-western part of the Hungarian Great Plain and a newly (2009) rediscovered population in north-western Hungary. Mark– release–recapture method was used to estimate the population size and describe population structure in a 0.65 ha habitat patch from 2005 to 2007. The population size did not fl uctuate during the 3 years; the total estimated number of individuals ranged between 130 and 270. The survival probability was 0.81–0.84/day in the case of males, in females 0.70–0.89/day. The catchability was between 0.27–0.53 in males and 0.22–0.38 in females. The structure of the population indicates that the False Ringlet is a sedentary butterfl y species, with low dispersal ability. In the study area, drainage seems to be the main threatening factor for its habitat. The studied population has recently moved to neighbouring lower parts of the habitat patch, because the formerly occupied part of the habitat patch had been desiccated and the vegetation had been changed. For the long-term survival of the species at this habitat patch the drainage should be inhibited, while in other habitat patches around, the control of invasive plant species is inevitable beside habitat restoration.