Year‐to‐year variation in carabid beetle (Coleoptera, Carabidae) assemblages on the Åland Islands, south‐west Finland

Abstract

Aims (1) To invesqigate changes in structure of carabid assemblages between sites on the main island of Aland and five small nearby islands between 1.982 and 1,999. (21 To determine whether island differences observed in one year is mirrored in another one. (3) To examine changes in abundance levels of individual carabid species on these islands since 1982. (a) To compare the proportion of flightless species on the main island of Aland with those on the small islands.Location Islands in the Baltic Sea, Finland; the main island of Aland (90,000 ha) and five small, nearby islands (8-29 ha).Methods Carabid beetles were collected, using pitfall traps, during 4 years (1. 982, 1.987, 1988 and 1999). Sampling took place in moist, spruce-dominated, lush forest patches.Results Overall, 12,1.27 individuals representing forty-six carabid species were collected; forty-one species (8580 individuals) on the main island of Aland, and thirty-one species (3547 individuals) on the small islands. Carabid assemblage structure, measured using ordination techniqqes, was consistently and significantly different between the main island and the small island sites. Carabid assemblage structure and abundances of individual species did change significantly between year-s, possibly because of a combination of climatological and habitat changes in the Aland archipelago. The six most abundant species collected on the small islands, and the three most abundant species overall, were all short-winged. Furthermore, the small islands had a higher proportion and number of short-winged species compared with the main island of Aland.Main conclusions Carabid assemblage structure was significantly different between the main island and the small islands in all years sampled, indicating that single-year studies are sufficient to demonstrate differences in carabid assemblages on Baltic islands. Small islands host a non-random proportion of species pools available on the main island of Ahnd and mainland FinlanJ. Iiappears that dispeisal to islands in the Baltic Sea is easy for carabid beetles of all wing forms, but that short-winged species are more successful colonizers.

Effects of reflective groundcovers on ground beetles (Coleoptera: Carabidae) in red raspberry (Rubus idaeus) cropping systems

“…Nevertheless, our observations that species richness and activity density are generally enhanced in organic rather than conventional agroecosystems are in agreement with the lit-erature (Dritschilo and Wanner 1980;Dritschilo and Erwin 1982;Faragalla and Adam 1985;Hokkanen and Holopainen 1986;Kromp 1989Kromp , 1990Booij and Noorlander 1992;Cá rcamo et al 1995;Pfiffner and Niggli 1996;Clark 1999;Shah et al 2003). Year-toyear variability in ground beetle catches could be attributed to many factors such as direct or delayed effects of weather conditions (Abildsnes and Tømmerå s 2000; Kotze and Niemelä 2002) or anthropogenic habitat alteration (Kotze and Niemelä 2002;Rainio and Niemelä 2003).…”

“…2003). Year‐to‐year variability in ground beetle catches could be attributed to many factors such as direct or delayed effects of weather conditions (Abildsnes and Tømmerås 2000; Kotze and Niemelä 2002) or anthropogenic habitat alteration (Kotze and Niemelä 2002; Rainio and Niemelä 2003).…”

Boreal ground-beetle (Coleoptera: Carabidae) assemblages of the mainland and islands in Lac la Ronge, Saskatchewan, Canada

“…As island size increased, the structure of the carabid assemblage on islands gradually approached that of the mainland where relative abundances of large-bodied, flightless species and small-bodied, flying species were more similar. In contrast, carabid beetle assemblages on Baltic islands up to~29 ha in size differed distinctly from the mainland (Niemelä et al 1985;Kotze and Niemelä 2002). Below, we suggest three possible explanations for differences that we observed in the structure of the assemblage between the smallest islands, on the one hand, and large islands and the mainland on the other.…”

Responses of Arthropod Fauna Assemblages to Goat Grazing Management in Northern Spanish Heathlands

“…Because the year ϫ treatment interaction model was nonsigniÞcant, the reasons for those annual variations were more likely related to weather conditions. For example, in carabids, climatological conditions have been regarded as decisive for population ßuctuations (Kotze and Niemelä 2002). González-Megṍas et al (2004) also found different arthropod species composition between years under different ungulate grazing regimens in Sierra Nevada and related them to the temporal variability in habitat productivity.…”