Some biological and chemical changes in a north Queensland soil following replacement of rainforest with Araucaria cunninghamii (Coniferae:Araucariaceae).
Abstract
The soil nutrient levels, standing crop of litter and populations of soil and litter arthropods of a tropical Australian rainforest on the Atherton Tableland in north Queensland are compared with those of an adjacent 41-year-old hoop pine (Araucaria cunninghamii D. Don) plantation. newline˜Organic carbon levels in the rainforest soil were markedly higher than in the hoop-pine plantation as were the levels of nitrogen, acid-extractable phosphorus and exchangeable calcium, magnesium and potassium. The standing crop of litter was markedly higher in the hoop-pine plantation than in the rainforest and showed strong seasonal variation related to the seasonality of litterfall and climatic events. Turnover rates (k) were lowest in the hoop-pine plantation. Large litter arthropods were less abundant in the hoop-pine plantation while Acari and Collembola were more abundant in the rainforest soils. newline˜It is suggested that the decline in organic matter and associated nutrients in the hoop-pine forest soil results from the loss of a large proportion of the plant nutrients from the ecosystem when the original rainforest was cleared. The subsequent establishment and growth of a hoop-pine plantation then lowered the existing soil nutrient supplies by transfer of nutrients into the vegetation.