Abundance and diversity of spiders from the canopy of tropical rainforests with particular reference to Sulawesi, Indonesia

Abstract

Spiders were sampled by knockdown insecticide fogging from the canopies of tropical rainforest sites in Dumoga-Bone National Park, Sulawesi, at altitudes of 210 m, 300 m, 400 m and 1150 m. The density of spiders in the canopies increased with altitude from 0.97 m−2at 210 m to 14.6 at 1150 m−2. Species numbers increased five-fold between 210 m and 1150 m but species diversity (α of the log series) was greatest at 210 m and least at 1150 m, partially due to dominance of the fauna by few species at the highest altitude. Similarity between the spiders' communities (as measured by the Morisita-Horn index) was greatest between canopies at 300 m and 400 m and least at 400 m and 1150 m.Theridiidae were abundant in forests at all altitudes, Pholcidae and Salticidae in the lowland forests between 210 m and 400 m and Clubionidae, Linyphiidae and Oonopidae in the montane forest at 1150 m. Theridiidae was the most species-rich family at all altitudes (22−30% of all species). Other species-rich families included Araneidae (7−19%) and Salticidae (8−17%) in lowland forests and Clubionidae (12%), Oonopidae (10%) and Salticidae (12%) in the montane forest.Published information on density, proportion and diversity of spiders in canopies of both tropical and temperate trees is reviewed and the results discussed in relation to those from the present study.

Canopy knockdown of arthropods in exotic plantations and natural forest in Sabah, north-east Borneo, using insecticidal mist-blowing

“…Certainly, arthropods such as spiders do vary in abundance in knockdown samples according to the altitude of the rainforest (Russell-Smith & Stork, 1994), but since all the study sites at Brumas were in the same area, with similar altitudinal and climatic conditions, lack of seasonal variation in the present study was to be expected. Data from the present study compare well with those from Brazilian and Indonesian trees where ants accounted for nearly 50% of fauna in knockdown samples (Erwin, 1983a,b;Adis et nl., 1984;Adis & Schubert, 1985).…”

“…Canopy knockdown in south-east Asia has most often been carried out using fogging techniques (Stork, 1987a(Stork, ,b, 1991Watanabe & Ruaysoongnern, 1989;Blanton, 1990;Stork & Brendell, 1990;Basset, 1991a,b;Casson & Hodkinson, 1991;Kitching et al, 1993;Russell-Smith & Stork, 1994;Basset et al, 1997;Guilbert, 1997), where a warm fog containing non-residual insecticide is generated by a thermal pulse-jet engine, which then rises into a tree canopy. Arthropods coming into contact with the chemical are killed or rendered unconscious, and fall to the ground where they are collected in trays.…”

Spider Assemblages in Costa Rican Cloud Forests: Effects of Forest Level and Forest Age

“…Even less is known of the spiders of tropical montane regions (e.g., Hanson, 2000) and spiders of tropical forest canopies (Russell-Smith & Stork, 1994;Basset, 2001). Ecological information for most groups can be found only as comments in taxonomic surveys (e.g., Zuñiga, 1980;Nentwig, 1993).…”

Diversidad de arañas (Araneae, Araneomorphae) en la selva de montaña: un caso de estudio en las Yungas Argentinas

“…Entre las familias de arañas dominantes en áreas naturales se encuentran generalmente Araneidae, Salticidae, Theridiidae, Anyphaenidae y Thomisidae (Flórez-D., 1998;Podgaiski et al, 2007;Ricetti & Bonaldo, 2008;Rubio et al, 2008), y en ambientes netamente boscosos y selváticos se agregan Tetragnathidae, Pholcidae y Linyphiidae destacándose entre las más abundantes (Russell-Smith & Stork, 1994;Flórez-D., 1998Flórez-D., , 1999Sørensen, 2004;Benati et al, 2005). En los ambientes de las yungas se observaron las mismas familias dominantes, y en lo que respecta a Linyphiidae, Tetragnatidae, Pholcidae y Mysmenidae se observó su afinidad por la selva y el bosque montanos.…”