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Densities of Collembola and Acarina in the soil and litter of three indigenous South Australian forests related to layer, site and seasonal differences
Author(s) -
HUTSON BARRY R.,
VEITCH L. G.
Publication year - 1987
Publication title -
australian journal of ecology
Language(s) - English
Resource type - Journals
eISSN - 1442-9993
pISSN - 0307-692X
DOI - 10.1111/j.1442-9993.1987.tb00946.x
Subject(s) - seasonality , prostigmata , mesostigmata , ecology , litter , temperate climate , fauna , mediterranean climate , biology , mite
A quantitative study was made of the micro‐arthropod fauna in the litter and two soil layers at three South Australian forest sites (designated ‘dry’ medium’ and ‘wet’) using data taken at monthly intervals over 2 years. This study examined variations in density estimates of the major taxonomic groups of Acarina and Collembola that were associated with sample depth, site and season. There were substantial differences in the proportions of variation attributed to layer, site and seasonal effects. Most variation was associated with layer differences, being greatest in the acarine Prostigmata and in the collembolan Onychiuridae. Only the acarine Astigmata had slightly more variation between sites than between layers. Seasonal variation exceeded site variation in all collembolan groups except the Entomobryidae. In the acarine groups estimated ratios of seasonal to site variation were 6.1, 1.6, 1.0 and 0.4 for the Mesostigmata, Prostigmata, Cryptostigmata and Astigmata, respectively. Some variations due to inconsistencies in the above patterns were significant statistically but were small compared with variations associated with the seasonal, layer and site effects. Densities of all animals had marked seasonal variation which was broadly similar to that of rainfall in the warm temperate, mediterranean type climate of the region. Minimum density and activity occurred in about the last week in January, a period of maximum temperature and low soil moisture content; maxima were usually about 7 months later. This contrasts with warm and cool temperate areas of Australia with summer rainfall, where peak densities have been recorded in summer. The Mesostigmata, Astigmata, Podundae and Onychiuridae patterns of seasonal variation did not differ significantly with layer or site differences. The remaining groups had significant differences with layers and sites, the former being larger. Density minima and maxima were generally later going from litter to lower soil, about 2.5–8 weeks for density maxima and 0–4 weeks for minima. Groups with significant lags showed reduced amplitude in their seasonal variation with increased depth. There was little seasonal variation in the relative proportions of all animal groups.