Abstract
Seasonal variation in standing crop, litter, pH and relative light intensity was measured in the field layer of two riverine forests near Bruges, Belgium. At each site the living fraction in 10 randomly selected 0.25 m2 quadrats was separated into various components and graphed in relation to the environmental variables. The effect of the environmental variables on standing crop was assessed using path analysis, based on the standardized partial regression coefficients obtained in separate stepwise multiple regressions. In order to linearize the relation between the standing crop and the environmental variables, and to meet other statistical assumptions, a log-transformation was applied to the standing crop data.
On an annual basis, 44% of the total variation in log-standing crop was explained by the variables litter, relative light intensity and pH, while seasonally the coefficient of determination ranged from 0.23 (November) to 0.72 (April). A general path diagram, based on all data, indicated predominant direct effect of litter (path coefficient: −0.55) and pH (0.26). Relative light intensity had only an indirect effect through its impact on litter and pH. Considerable seasonal changes occurred in the importance of litter, relative light intensity and pH.
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Nomenclature follows De Langhe et al. (1983) Flora van België.
This study was supported by a grant from the ‘National Fund of Scientific Research’ from 1979 to 1984. I am also indebted to Drs P. Meire for statistical advice and critical comments, to M. Geens for field assistance and Dr J. Kuusipalo for reviewing the manuscript.
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Hermy, M. Path analysis of standing crop and environmental variables in the field layer of two Belgian riverine forests. Vegetatio 70, 127–134 (1987). https://doi.org/10.1007/BF00039326
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DOI: https://doi.org/10.1007/BF00039326