SECTION ENTOMOLOGY
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SECTION ENTOMOLOGY |
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Research for third parties performed at the Department of Entomology.
Monitoring for third parties.
Over the last ten years, the Department of Entomology has done several field research commissions for parties outside the University. These are engineering firms like Oranjewoud and DHV, but also Mission of Public Works, County Council North-Holland and the Forestry Commission. Although the research questions vary, survey fieldwork is always involved as the presence or absence of certain species may provide valuable information. An analysis is made of the sampled species combined with their ecological details. From ground beetles especially a lot is known about habitat preferences and they provide much information about of the development of nature in man made habitats or restored habitats. Ground beetles react quick on changes and by the many species and specimens tendencies are quick to recognise. A list of research performed in the last ten year:
The nature development projects are valuable as steppingstones and refuges for insect species occurring in poor grasslands, however, the small areas of the projects makes them unimportant to birds and plants. Based on these results those small nature development projects are found to be successful. After five years the pioneer stage of the development of the ground beetle fauna has been completed. Further development requires vegetation management, which is often neglected due to the managers' lack of knowledge. The ground beetle fauna was also monitored in nature development projects in the dunes of North-Holland, between 1991 and 1996. The sites were the surroundings of the 'Lioba-monastery' at Egmond-binnen, the 'Pirolavalley' at Groet and the 'Moksloot' at Texel. The question is: does nature develop into habitats which are rich or poor in nutrition in these sites? In the pioneer stage many rare or threatened species were found. After two years it became clear how the sites develop, most sites develop into a habitat which is rich in nutrients. The level of precipitation is an important factor - too high and development may be set back. Especially in the Pirolavalley, the fauna is dynamic because dune valleys are alternately flooded and dry. Grazing cattle and birds (geese) often had a disturbing influence on the development, signs of which can still be found in the recent fauna.
Research of the ground beetle fauna in man-made wet edges of bulb fields which are reminiscent of former dune brooks. In the first year an interesting fauna of pioneer species colonised the dune sites, and also the sites which lay further away from the dunes. In the second year the site will develop into one poor or rich in nutrition, with few specialist species in the latter case. The survey will determine if development of nature and the cultivation of bulbs combine.
It is expected that a dynamic salt marsh will be formed. In 1997 the research started by an examination of the original fauna of the area to determine which species that are usually associated with dynamic dune areas, were already living there. The crowberry fields were found to be sparsely populated with ground beetles, other insects and spiders. The poorly covered southern slopes were rich with rare and threatened species. The development of the ground beetle fauna will be monitored.Will a fauna of sweet dune valleys, salt meadows, beach area and blowing sand dunes form on the drier parts? These habitats have become scarce in North-West Europe and therefore the Netherlands play an important role in the distribution area of specialised ground beetles. The results from 1998 will make the development patterns clear. In the coming years the development will be influenced by the number of salt floods in the winter and the quantity of precipitation in the other seasons. All factors are important for certain ecological groups of ground beetles. It is important that all ecological groups can inhabit or colonise the area and stay there. Especially the saline-adapted species are important on an international scale, because they only have a small suitable area in Europe.
Ben Brugge tel. 020-5256258
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