Filtern
Dokumenttyp
- Wissenschaftlicher Artikel (2) (entfernen)
Sprache
- Deutsch (2)
Volltext vorhanden
- ja (2)
Gehört zur Bibliographie
- nein (2)
Schlagworte
- habitat classification (2) (entfernen)
Epigeic spiders were sampled using pitfall traps during one year in an anthropogenic open site within the city of Karlsruhe (Alter Flugplatz Karlsruhe). The area, historically used as a military parade ground and airport, is protected as a Special Area of Conservation (SAC) within the Natura 2000 network of the EU and since 2010 as a German nature reserve. We were interested in the diversity, assemblage structure and distribution of spider species within the area and investigated three different plant formations: sparse grass-dominated vegetation with frequent open sand patches (sandy turf ), closed grassland dominated by the mat-grass (Nardus stricta) and ruderal vegetation with blackberry bushes. 123 species were identified from these captures, including many specialists of xerothermic habitats and rare and endangered species like Alopecosa striatipes, Agroeca lusatica, Haplodrassus dalmatensis, Styloctetor romanus, Typhochrestus simoni and Xysticus striatipes as well as extremely rare species of unclassified red list status like Mysmenella jobi, Theonoe minutissima and Zora parallela. The three investigated habitat types were quite similar concerning α-diversity, while measures of β-diversity indicated a strong species turnover. By performing an ecological habitat analysis (using autecological data on spiders) essential differences between the three habitat types could not be discovered, especially not between mat-grass and sandy turf. However, analysing the guild structures showed that different ways of using habitat resources dominated in the different habitat types. For Nardus-grassland several species could be identified as indicator species. While many xero- and photophiles live in the open grassland, the stenotopic psammophiles of inland dunes in the region were not found. The ruderal area houses a mix of grassland- and forest species.
The data presented by HÄNGGI et al. (1995) and BOLAÑOS (2003) on the habitats of a large number of European spiders are examined, most of which appear to show non-specific preferences. The abundance and frequency peaks of the 384 species graphs (HÄNGGI et al. 1995) can be explained by assuming that habitat tolerance varies with geographical location. This can be demonstrated on a local level within a particular country or throughout the European range of a species. Examples are described. Many published ecological studies of spider faunas seem to have assumed that the habitat preferences of a species is a fixed characteristic wherever they occur but evidence is presented to show that this may apply to only a few species. A number of examples are described showing how preferences change with latitude and longitude within Europe. It is proposed that most species can be categorised as stenotopic, mesotopic or eurytopic, although there is a gradual change from one group to another, with no clear boundaries. Supporting evidence for regional variation in habitat tolerance is scarce. More studies are required of individual species throughout their European distribution and detailed descriptions of their habitats in different parts of their range. Definitions of micro-, macro- and minor habitats are presented as useful tools for field studies of spider faunas. It is also recommended that future faunal surveys should use the same system of habitat classification so that the results are comparable with other studies. The most appropriate method is described by BUCHAR & RŮŽIČKA (2002) but could be made more precise by the use of scientific measuring equipment for light/shade, dryness/humidity and temperature. Finally the importance of checking the validity of some published records is stressed because misidentifications are sometimes frequent.