Query: keyword: "habitat"
|Authors||G. de Knijf, A. Anselin, P. Goffart|
|Title||Trends in dragonfly occurrence in Belgium (Odonata)|
|Publisher||European Invertebrate Survey - the Netherlands|
|Book/source title||Changes in ranges: invertebrates on the move. Proceedings of the 13th International Colloquium of the European Invertebrate Survey, Leiden, 2-5 September 2001|
|Editors||M. Reemer, P.J. Helsdingen, R.M.J.C. Kleukers|
|Keywords||Odonata; Dragonflies; Belgium; Atlas; Hot spot; Abundance class shift; Habitat|
|Abstract||Trends in dragonfly occurrence in Belgium (Odonata) |
The group ‘Gomphus’ collected 65 000 records of 69 species of Odonata, more or less equally scattered over Belgium. The best-investigated areas are the northern part and some river valleys in the south. Most hot spots can be found in the northeastern part, with a maximum of 48 species for 25 km². Remarkable is the fact that 50% of the species occurs in less than 7% of the 5 km grid cells (UTM). We determined trends in occurrence by comparing three periods: before 1950, 1950-1989 and 1990-2000. Four species show a clear decline over the three periods, eight species give evidence of a historical decline but survive on a limited number of sites and eight species also display a historical decline but have been increasing during the last decade. Six species show a (very) clear increase over the three periods and two species display their increase only during the last ten years.
|Download paper|| http://www.repository.naturalis.nl/document/46392 |