Transformation of soil macrofauna in the first year after deforestation
A.A. Ditts, T.N. Konakova, A.A. Fateeva
Section: Monitoring of natural and anthropogenically disturbed areas
Soil macrofauna of primary forests of the middle taiga is characterized by high abundance (94.6–146.6 ind./m2), taxonomic richness (10–14 taxa), dominance of Diptera and Cantharidae larvae, similarity of fauna composition (J=0.60–0.65), with a ratio of detritivores and predators equal to 1:1, aggregated or random horizontal distribution. The total density of invertebrates sharply decreases (4.5–26.8 ind./m2) in the first year after deforestation. Some taxa are eliminated from the fauna, 4–7 taxa are remained. The ratio of trophic groups is changed. The distribution of invertebrates in space is disturbed. Soil macrofauna of clear-cutting areas (CCA) retains a taxonomic structure close to the control sites (C). The taxonomic and trophic structure of soil macrofauna is more disturbed on the logging corridors (LC) with three (3LC) and ten (10LC) penetrations of aggregate equipment, recultivated (RLC) and main (MLC) logging corridors. Thus, the density of Diptera larvae is high on the logging corridors. The above are temporary r-strategists characteristic for the disturbed environment. And the ratio of detritivores and predators on the technological sites “C – CCA – 3LC – 10LС – RLC – MLC” is 1:1 – 3:1 – 7:1 – 10:1 – 13:1 – 15:1. A trend towards an increase in the density of detritivores on the recultivated (RLC) and main (MLC) logging corridors was noted. The decrease of the total density of macrofauna and the declining of systematic groups of the clear-cutting areas is not so significant due to the fact that the litter on these sites is almost completely preserved after felling. The low diversity of soil macrofauna on the logging corridors can be explained by a change in the natural conditions for the existence of invertebrates due to the compaction of the upper soil horizons, the partial disappearance of the litter, the appearance of a mineralized soil layer as top horizon, and a rapid change in humidity. Significant changes in the abundance, composition, and ratio of trophic groups of invertebrates indicate the collapse of soil macrofauna, the loss of important groups of destructors and predators from food webs, and a decrease in the quality of their functions at the initial stage of restorative succession, in the first year after deforestation.
ISSN 1995-4301
Select viewing options
