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Microclimate Control of Growth Rates and Habitats of the Boreal Forest Mosses, Tomenthypnum nitens and Hylocomium splendens
Author(s) -
Busby John R.,
Bliss L. C.,
Hamilton Catherine D.
Publication year - 1978
Publication title -
ecological monographs
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.254
H-Index - 156
eISSN - 1557-7015
pISSN - 0012-9615
DOI - 10.2307/2937294
Subject(s) - moss , canopy , shrub , deserts and xeric shrublands , environmental science , taiga , sclerophyll , ecology , botany , biology , habitat , mediterranean climate
Tomenthypnum nitens forms tall turfs in fens where the tree and shrub canopy is sparse and the water table is close to the surface. The feather moss species (Hylocomium splendens, Pleurozium schreberi, and Ptilium crista—castrensis) form wefts in shaded and better drained habitats. Growth of T. nitens was measured using small wire stakes, from which net production averaged 190 g/m 2 in 1975. Growth rates were correlated with color of the apical region, the result of variation in apical water contents. Seasonal variation in growth rate was correlated with depth from the canopy surface to the ground water table, controlled by the balance between rate of transport of water through the canopy and loss by evaporation. The most important environmental factor appears to be total precipitation, followed by evaporation stress. Growth of the feather mosses was estimated by measuring dry weight changes of segments of Hylocomium splendens. Net production averaged 79 g/m 2 . Growth was correlated with the length of time that the moss was wet, the result of precipitation frequency. Because growth rates were measurably reduced by removal of a sparse shrub canopy, evaporation stress is probably another important factor. Survival and growth of Tomenthypnum nitens is limited by evaporation stress in habitats where ground water is not available. Feather mosses are limited by radiation damage and evaporation stress in open habitats, by depression of net assimilation and other deleterious effects of saturation in wet habitats, and by insufficient rainfall under dense tree canopies.