Acari and Collembola of Moorland Soils from Yorkshire, England I. Description of the Sites and Their Populations

Abstract

The mean population densities of Acari and Collembola were found to be similar in cushion protorendzinas under mosses (Camptothecium and Tortella) on limestone boulders (277,000-281,000/m2), a mull-like rendzina under Sesleria on cliff ledges (178,000/m2), a brown earth of low base status under Festuca-Agrostis (225,000/m2), and 2 gleyed podsolic brown earths under Nardus (167,000/m2). Prostigmata and Cryptostigmata (Acari) dominated in all sites except the brown earth where Collembola were more abundant than Prostigmata. There were few Mesostigmata in the mosses, and Astigmata were scarce in mosses and the mull-like rendzina. The greatest number of species (128) occurred in the mull-like rendzina, and a total of 200 spp. were recorded from 11 sites. The supposed logarithmic relationship between numbers of species and numbers of individuals did not hold for these populations. Species-individual curves showed the populations in the brown earth to be the most homogeneous and the populations in the mull-like rendzina to be the most heterogeneous.