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Soil and litter respiration in rainforests of contrasting nutrient status and physiognomic structure near Lake Eacham, north‐east Queensland
Author(s) -
MAGGS JOHN,
HEWETT BOB
Publication year - 1990
Publication title -
australian journal of ecology
Language(s) - English
Resource type - Journals
eISSN - 1442-9993
pISSN - 0307-692X
DOI - 10.1111/j.1442-9993.1990.tb01037.x
Subject(s) - litter , soil respiration , plant litter , nutrient , dry season , rainforest , environmental science , wet season , agronomy , ecology , soil water , biology
Soil and litter respiration and nutrient concentrations (N, P, Ca, Mg and K) were measured in two adjacent rainforests near Lake Eacham on the Atherton Tableland in north‐east Queensland. One forest had soil formed on basalt and, in physiognomic‐structural classification of Webb (1968, 1978), was structurally complex. The other had soil formed on metamorphic rock and was structurally simple. Respiration was measured by the alkali trap method on 16 monthly occasions in 1986 and 1987. Soil and litter nutrient concentrations were higher in the complex forest (with the exception of soil N). The relative differences were greater for soil than litter and more pronounced for P and Ca (and also soil Mg) than other nutrients. Litter polyphenol concentrations were lower in the complex forest. Rates of litter respiration in the complex forest were, on average, nearly twice those of the simple forest. Soil respiration rates were occasionally slightly lower in the complex forest during the wet season but did not differ between the forests during the dry season. Highest rates of respiration were measured during the wet season although high rates for litter occasionally occurred during the dry season. Cumulative CO 2 release from the soil and overlying litter did not differ between forests and averaged 5134 ± 96 g CO 2 m ‐2 per year (mean ± s.e.m.) (1400 g C m ‐2 per year). Litter respiration accounted for 14% of the annual release in the complex forest and 11% in the simple forest. The association between site nutrient status and forest physiognomic structure at Lake Eacham represents a more general pattern in rainforests of north‐east Queensland. Further study is needed to ascertain whether the results from this study apply more generally in both primary and secondary rainforests.