Articles containing the keyword 'vertebrate'

Invertebrates of young Scots pine (Pinus sylvestris L.) stands were preliminarily studied along a gradient of industrial air pollutants in Harjavalta, south-western Finland. Bark samples and net samples on pine branches and needles were taken in May–June, 1987. The number of aphids on needles was highest near the industrial plants. The number of mites in bark was positively correlated with the increasing distance from the pollutant source. Detrended correspondence analysis ordination calculated according to the bark invertebrates showed that the sampling sites of the zones far from the emission source formed a distinct group while those of the zones near the source were relatively widely dispersed indicating disturbances in faunal structure.

The PDF includes an abstract in Finnish.

• Heliövaara, E-mail: kh@mm.unknown
• Väisänen, E-mail: rv@mm.unknown

The abundance of main invertebrate groups was studied in clear-fellings, forests and in edges between them in Northern Finland in June-August 1983. Five trapping transects were used. Each transect had 48 pitfall traps and 16 window traps on the ground and 4-6 window traps in bushes or trees.

Invertebrate groups Homoptera, Diptera, Formicidae, Coleoptera and Gastropoda were more abundant in forest than in clear-cuts according to the pitfall data. In window traps the catches of all the main groups were larger in the forest side. Six out of the eight most important groups preferred the edge in pitfall data. Formicidae, other Hymenoptera, Arachnida and Gastropoda were more numerous in the edges than in the interior habitats in both sides of the edge. In window trap material no consistent edge preference was found in clear-fellings, but in the forest side it was evident. Coleoptera and Arachnida preferred the edge on both sides of it.

The variations in the catches of the invertebrate groups were studied by regression analyses. Independent variables used were the distance to the edge, the coverage of mosses, litter, mineral soil, grasses and sedges, herbs and the density of saplings. The percentage of variance explained in multiple regression analyses were highest for the group of other Hymenoptera and Arachnida and lowest for Coleoptera and Homoptera. As regards the explanation power of the independent variables the distance to the edge and the density of saplings clearly exceeded the others.

The results support the assumption that the breeding bird densities at forest edges, which is often high, may depend on high prey density there.

The PDF includes a summary in Finnish.

• Helle, E-mail: ph@mm.unknown
• Muona, E-mail: jm@mm.unknown

The subarctic-subalpine mountain birch forest zone discerns Fennoscandia from other northern regions. The zone offers protection against wind to animal life, protects soil from evaporation and increases humidity. The article reviews distribution of vertebrate and butterfly species in the birch forest zone. There are no vertebrates that occur solely in the birch forest zone, and only few live mostly in the zone. Many species live either both on the birch forest zone and the treeless fell area above it, or in the birch forest zone and coniferous zone below it. Similarly, no butterflies occur only in the birch forest zone, but the zone is the main habitat for some species. Consequently, the subarctic-subalpine birch forest zone cannot be considered to be an independent ecozone but a transitional zone between regio silvatica and regio arctica that is nearer to the northern coniferous zone than the fell region

The PDF includes a summary in German.

• Valle, E-mail: kv@mm.unknown

The effect of different fertilizer treatments on the invertebrate fauna on coniferous forest soil were investigated during the years 1979-83 both in field and in laboratory experiments. Fertilizers tested were urea (both alone and with P and K), ammonium nitrate and ashes. Ash-treatment was also controlled by raising the pH at the same level with Ca(OH)₂.

Both ashes and urea resulted in considerable changes in the soil fauna. Nematodes, especially bacterial feeders, increased temporarily. Some families of Coleoptera invaded the urea-treated plots. Enchytraceid worms and several microarthropod species decreased, as well as the total animal biomass. Ash-treatment influenced more slowly than did urea-fertilizing, but it caused more permanent changes. Ammonium nitrate with lime had little influence in the field. All fertilizers affected more strongly when mixed with soil in laboratory. pH alone proved to explain most of the changes observed, but nitrogen as a nutrient also plays role independently of acidity.

The PDF includes a summary in Finnish.

• Huhta, E-mail: vh@mm.unknown
• Hyvönen, E-mail: rh@mm.unknown
• Koskenniemi, E-mail: ak@mm.unknown
• Vilkamaa, E-mail: pv@mm.unknown
• Kaasalainen, E-mail: pk@mm.unknown
• Sulander, E-mail: ms@mm.unknown

The effects of modern forestry on northwest European forest invertebrates are summarized and analysed mainly on the basis of published literature. The direct influence of different practices including clear-cutting, thinning, burning-over, ploughing, changes in tree species composition of stands, fertilization, insecticides, pheromones and biological control are discussed from a forest zoological point of view. Also, the indirect effects of general changes in boreal forest dynamics, loss of primeval forests, cessation of natural fires and the dominance of young stands are described. The direct effects of different silvicultural practices on the species composition and diversity of forest invertebrates are usually considered to be striking but transient. However, when large areas are treated, the species associated with primeval forests, especially with the wood composition system in them, as well as the species associated with fires, seem to have drastically declined. In northwest Europe, efficient forestry has not caused such serious pest problems as is known from tropical countries or North America.

The PDF includes a summary in Finnish.

• Heliövaara, E-mail: kh@mm.unknown
• Väisänen, E-mail: rv@mm.unknown