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Some observations on the biomass and distribution of cryptogamic epiphytes in the upper montane forest of the Rwenzori Mountains, Uganda
Author(s) -
PENTECOST ALLAN
Publication year - 1998
Publication title -
global ecology and biogeography letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.164
H-Index - 152
eISSN - 1466-8238
pISSN - 0960-7447
DOI - 10.1046/j.1466-822x.1998.00297.x
Subject(s) - montane ecology , epiphyte , ecology , biomass (ecology) , geography , distribution (mathematics) , biology , mathematical analysis , mathematics
Measurements were made of the percentage cover, biomass and species‐richness of cryptogamic epiphytes growing upon mature Phillipia phillipia stands in the ericaceous (upper montane) forest of the Rwenzori Mountains, Uganda. Macrolichens, especially Usnea spp., dominated the upper canopy, while a range of large cushion‐forming hepatics (e.g. Chandonanthus , Herbertus , and Plagiochila species) dominated the lower canopy. The distribution of cryptogams was largely controlled by light intensity and phorophyte age Detailed studies of a felled Phillipia revealed twenty‐nine epiphyte species (two algae, fourteen bryophytes, eleven lichens and two ferns). The forest appears to be moderately species‐rich with a small number of species providing a large proportion of the cryptogam biomass. Total biomass of the epiphytes was close to 1 tonne ha −1 , representing about 10% of the above‐ground standing crop. Concentrations of N, P and K in the epiphytes were estimated as 10, 1, and 3 kg ha −1 respectively. The lichens and bryophytes contained about 2% and 8% respectively of the total above‐ground nutrients Microclimate measurements below the forest canopy demonstrated constant high humidity with suboptimal radiation. Air temperature below the canopy averaged 7.6°C (range 4–9.5°C) during a 10‐day period, and increased slightly with canopy height. Evaporation below the forest canopy showed a significant decline as altitude increased from 2300 to 3600 m.