Overlapping generations can balance the fluctuations in the activity patterns of an endangered ground beetle species: long-term monitoring of Carabus hungaricus in Hungary
Correspondence: Sándor Bérces, Duna-Ipoly National Park Directorate, Költő utca 21, H-1121 Budapest, Hungary. E-mail: firstname.lastname@example.org
- Carabus hungaricus is a ground beetle inhabiting the Pannonian steppes. It is highly endangered by fragmentation and abandonment of its habitat.
- For five consecutive years, from 2006 to 2010, we used the mark–release-recapture technique in a grid of 270 live-capture pitfall traps to study its population ecology in sandy grasslands on Szentendrei Island in the Northern vicinity of Budapest, Hungary.
- In total, 3950 individuals of C. hungaricus (1874 females and 2076 males) were marked.
- Population size was estimated at∼2000 individuals per year; the estimates for females were consistently higher than those for males. The minimum population size was 1317 ± 60.1 individuals in 2007, whereas the maximum was 2169.7 ± 108.8 individuals in 2008.
- Adults older than a year formed∼32–42% of the population, whereas individuals surviving for 3 years formed∼10%, and those surviving for 4 years formed∼2% of the population. Individuals older than 4 years comprised <1% of the population. Female survival rate was higher than that of male, but the capture rate also differed between sexes.
- Although the studied population showed considerable fluctuations in the pattern of activity during the 5 years, its size seemed to be relatively stable, underlining the importance of overlapping generations.