2015. augusztus 10., hétfő

Boda et al. (2015) Journal of Insect Conservation

Réka Boda, Csaba Bereczki, Adrienne Ortmann-Ajkai, Péter Mauchart, Bálint Pernecker, Zoltán Csabai (2015): Emergence behaviour of the red listed Balkan Goldenring (Cordulegaster heros Theischinger, 1979) in Hungarian upstreams: vegetation structure affects the last steps of the larvae. Journal of Insect Conservation 19(3): 547-557.

In odonates, the emergence behaviour and finding suitable substrates for successful molting may influence the next generation and ultimately can determine the survival of the entire population. Understanding emergence behavior of endangered species and those granted special conservation status is particularly important. Despite this, little is known about the life history and emergence behaviour of Cordulegaster heros, a characteristic inhabitant of headwater streams. We hypothesised that the taxonomic composition and structure of the vegetation significantly affect the travel distance to the emergence site and the substrate choice. Two stream sections with different riparian zone vegetation were surveyed for exuviae in the emergence periods in two consecutive years, supported with detailed vegetation mapping. Significant differences were found between the vegetation characteristics at the two sites and differences were also found between emergences in edge zones within a site, indicating that the importance of vegetation structure operates within the scale of sites as well as between sites. At the site with more diverse vegetation, smaller horizontal but higher vertical travel distances and more varied emergence substrate choice were found. Habitat composition and complexity appears to determine the emergence behaviour of C. heros, so for the successful conservation of this species we recommend choosing appropriate forest management regimes and even maintaining riparian forests in near-pristine condition.

Odonata, Exuviae, Travel distances, Emergence-site selection and preference, Vegetation grid mapping

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