Monday, August 3, 2009PS 7-73: Epiphytic soils of the canopy emergent Eucryphia Cordifolia (Cunoniaceae) in a coastal rainforest of Chiloé Island, Chile
Camila F. Tejo, University of Washington, Ivan Diaz, Institute of Ecology and Biodiversity and CASEB, Pontificia Universidad Católica de Chile, Mauricio E. Peña, P. Universidad Catolica de Chile, and Juan J. Armesto, P. Universidad Catolica de Chile, IEB, Universidad de Chile; CASEB Departamento de Ecologia.
Background/Question/Methods
Epiphytic soil derives from litter and organic matter accumulated on tree trunks and branches. This compartment can be a substantial portion of old-growth forest biomass. This dead biomass could be a subsidiary source of nutrients for temperate forests, in addition to litter on the ground. Temperate evergreen rainforests of southern South America have a multistratified canopy with many emergent trees, fully covered by vascular and non-vascular epiphytes. Epiphytic biodiversity and its ecological functions remain largely unknown and have been generally overlooked. We characterized the epiphytic soils of canopy emergent trees in a coastal temperate rainforest in Chilóe Island (42ºS). We selected the most frequent emergent tree species, Eucryphia Cordifolia, which represented 40-60% of the basal area. The study was conducted in a large tract of old-growth rain forest in Guabún, 30 km northwest of Ancud. Canopy emergents in this rainforest are 400 years old. To access the forest canopy we used rope-based tree-climbing techniques. Epiphytic biomass (plants + soil) of emergent Eucryphia trees (DBH >1m) was estimated by removing epiphytes from two large trees. We compared water, pH, carbon, ammonium and nitrate contents in epiphytic soils (8, 12 and 16 m from the ground) with samples from the forest floor.
Results/Conclusions
Epiphytic biomass accumulated on the main trunk and branches of Eucryphia trees was estimated in about 15 tons per ha (dry weight), with 70% corresponding to epiphytic soil and the remaining to live epiphyte biomass. We did not find significant differences in ammonium and nitrate content between epiphytic and forest ground soil samples. We conclude that epiphytic soil could be an important but often overlooked source of nutrients for these ecosystems, and because of similar carbon contents and pH, mineralization processes can operate in epiphytic soil as on the ground. Because carbon stored in epiphytic soil and live biomass can be up to 10% of the total biomass for these old-growth forests, the conservation of forest structure and old emergent trees is highly relevant to both nutrient use efficiency and carbon retention within this ecosystem. Epiphytic soils are relevant to ecosystem services provided by temperate costal forests.
Keywords: Canopy ecology, austral temperate forest, epiphytic soil, nutrients cycles.
Acknowledgments: Fondecyt number 1050225, 1050830, Canon National Parks Science Scholars Program.
Epiphytic soil derives from litter and organic matter accumulated on tree trunks and branches. This compartment can be a substantial portion of old-growth forest biomass. This dead biomass could be a subsidiary source of nutrients for temperate forests, in addition to litter on the ground. Temperate evergreen rainforests of southern South America have a multistratified canopy with many emergent trees, fully covered by vascular and non-vascular epiphytes. Epiphytic biodiversity and its ecological functions remain largely unknown and have been generally overlooked. We characterized the epiphytic soils of canopy emergent trees in a coastal temperate rainforest in Chilóe Island (42ºS). We selected the most frequent emergent tree species, Eucryphia Cordifolia, which represented 40-60% of the basal area. The study was conducted in a large tract of old-growth rain forest in Guabún, 30 km northwest of Ancud. Canopy emergents in this rainforest are 400 years old. To access the forest canopy we used rope-based tree-climbing techniques. Epiphytic biomass (plants + soil) of emergent Eucryphia trees (DBH >1m) was estimated by removing epiphytes from two large trees. We compared water, pH, carbon, ammonium and nitrate contents in epiphytic soils (8, 12 and 16 m from the ground) with samples from the forest floor.
Results/Conclusions
Epiphytic biomass accumulated on the main trunk and branches of Eucryphia trees was estimated in about 15 tons per ha (dry weight), with 70% corresponding to epiphytic soil and the remaining to live epiphyte biomass. We did not find significant differences in ammonium and nitrate content between epiphytic and forest ground soil samples. We conclude that epiphytic soil could be an important but often overlooked source of nutrients for these ecosystems, and because of similar carbon contents and pH, mineralization processes can operate in epiphytic soil as on the ground. Because carbon stored in epiphytic soil and live biomass can be up to 10% of the total biomass for these old-growth forests, the conservation of forest structure and old emergent trees is highly relevant to both nutrient use efficiency and carbon retention within this ecosystem. Epiphytic soils are relevant to ecosystem services provided by temperate costal forests.
Keywords: Canopy ecology, austral temperate forest, epiphytic soil, nutrients cycles.
Acknowledgments: Fondecyt number 1050225, 1050830, Canon National Parks Science Scholars Program.
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