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Epiphytic Bryophytes (epiphytic + bryophyte)

Distribution by Scientific Domains
Life Sciences100%

Selected Abstracts

Retention of Inorganic Nitrogen by Epiphytic Bryophytes in a Tropical Montane Forest,

BIOTROPICA, Issue 3 2005
Kenneth L. Clark
ABSTRACT We developed and evaluated a model of the canopy of a tropical montane forest at Monteverde, Costa Rica, to estimate inorganic nitrogen (N) retention by epiphytes from atmospheric deposition. We first estimated net retention of inorganic N by samples of epiphytic bryophytes, epiphyte assemblages, vascular epiphyte foliage, and host tree foliage that we exposed to cloud water and precipitation solutions. Results were then scaled up to the ecosystem level using a multilayered model of the canopy derived from measurements of forest structure and epiphyte mass. The model was driven with hourly meteorological and event-based atmospheric deposition data, and model predictions were evaluated against measurements of throughfall collected at the site. Model predictions were similar to field measurements for both event-based and annual hydrologic and inorganic N fluxes in throughfall. Simulation of individual events indicated that epiphytic bryophytes and epiphyte assemblages retained 33,67 percent of the inorganic N deposited in cloud water and precipitation. On an annual basis, the model predicted that epiphytic components retained 3.4 kg N ha/yr, equivalent to 50 percent of the inorganic N in atmospheric deposition (6.8 kg N ha/yr). Our results indicate that epiphytic bryophytes play a major role in N retention and cycling in this canopy by transforming highly mobile inorganic N (ca. 50% of atmospheric deposition is NO,3) to less mobile (exchangeable NH+4) and recalcitrant forms in biomass and remaining litter and humus. RESUMEN En este estudio se desarrollo y se evaluo un modelo para estimar la retención de nitrogeno (N) inorganico atmospherico en el dosel de un bosque tropical montano en Monteverde, Costa Rica. Primeramente, estimamos la retención de N inorganico en muestras de briófitas, grupos de epífitas, hojas de epífitas, y hojas de árboles que fueron expuestas a agua de neblina y de lluvia. Basandose en medidas de estructure del bosque y la biomasa de epífitas se derivo un modelo multi nivel de dosel, estos resultados fueron aumentados a la escala de ecosystema. El modelo fue guiado por datos meteorológicos tomados a cada hora y datos de deposición atmosféricos y las predicciónes del modelo fueron evaluadas con medidas de la lluvia indirecta (throughfall) del sitio. Las predicciónes del modelo fueron similares a los datos de campo para eventos individuales, el ciclo hidrológico anual y las fluctuaciones de N en la lluvia indirecta. La simulación de eventos individuales indicaron que las briófitas y grupos de epífitas retuvieron 33,67 por ciento de N inorganico en agua de nubes y de lluvia. Predicciónes anuales del modelo indican que los grupos de epífitas retienen 3.4 kg N ha/año, equivalente al 50 por ciento del N inorganico en la deposición atmosférica (6.8 kg N ha/año). Nuestros resultados indican que las briófitas en el dosel desempeñan un papel muy importante en la retención y ciclaje de N inorganico, porque transforman el N con alta mobilidad en N de baja mobilidad y a formas mas recalcitrantes en la biomasa, la hojarasca y el humus. [source]

Species richness patterns and metapopulation processes , evidence from epiphyte communities in boreo-nemoral forests

ECOGRAPHY, Issue 2 2006
Swantje Löbel
For several epiphyte species, dispersal limitation and metapopulation dynamics have been suggested. We studied the relative importance of local environmental conditions and spatial aggregation of species richness of facultative and obligate epiphytic bryophytes and lichens within two old-growth forests in eastern Sweden. The effect of the local environment was analyzed using generalized linear models (GLM). We tested whether species richness was spatially structured by fitting variogram models to the residuals of the GLM. In addition, we analyzed the species-area relationship (area=tree diameter). Different environmental variables explained the richness of different species groups (bryophytes vs lichens, specialists vs generalists, sexual vs asexual dispersal). In most groups, the total variation explained by environmental variables was higher than the variation explained by the spatial model. Spatial aggregation was more pronounced in asexually than in sexually dispersed species. Bryophyte species richness was only poorly predicted by area, and lichen species richness was not explained by area at all. Spatial aggregation may indicate effects of dispersal limitation and metapopulation dynamics on community species richness. Our results suggest that species groups differ in habitat requirements and dispersal abilities; there were indications that presence of species with different dispersal strategies is linked to the age of the host tree. Separate analyses of the species richness of species groups that differ in the degree of habitat specialization and dispersal ability give insights into the processes determining community species richness. The poor species-area relationship, especially in lichens, may indicate species turnover rather than accumulation during the lifetime of the host tree. Epiphyte species extinctions may be mainly caused by deterministic processes, e.g. changes in habitat conditions as the host tree grows, ages and dies, rather than by stochastic population processes. [source]

Retention of Inorganic Nitrogen by Epiphytic Bryophytes in a Tropical Montane Forest,

BIOTROPICA, Issue 3 2005
Kenneth L. Clark
ABSTRACT We developed and evaluated a model of the canopy of a tropical montane forest at Monteverde, Costa Rica, to estimate inorganic nitrogen (N) retention by epiphytes from atmospheric deposition. We first estimated net retention of inorganic N by samples of epiphytic bryophytes, epiphyte assemblages, vascular epiphyte foliage, and host tree foliage that we exposed to cloud water and precipitation solutions. Results were then scaled up to the ecosystem level using a multilayered model of the canopy derived from measurements of forest structure and epiphyte mass. The model was driven with hourly meteorological and event-based atmospheric deposition data, and model predictions were evaluated against measurements of throughfall collected at the site. Model predictions were similar to field measurements for both event-based and annual hydrologic and inorganic N fluxes in throughfall. Simulation of individual events indicated that epiphytic bryophytes and epiphyte assemblages retained 33,67 percent of the inorganic N deposited in cloud water and precipitation. On an annual basis, the model predicted that epiphytic components retained 3.4 kg N ha/yr, equivalent to 50 percent of the inorganic N in atmospheric deposition (6.8 kg N ha/yr). Our results indicate that epiphytic bryophytes play a major role in N retention and cycling in this canopy by transforming highly mobile inorganic N (ca. 50% of atmospheric deposition is NO,3) to less mobile (exchangeable NH+4) and recalcitrant forms in biomass and remaining litter and humus. RESUMEN En este estudio se desarrollo y se evaluo un modelo para estimar la retención de nitrogeno (N) inorganico atmospherico en el dosel de un bosque tropical montano en Monteverde, Costa Rica. Primeramente, estimamos la retención de N inorganico en muestras de briófitas, grupos de epífitas, hojas de epífitas, y hojas de árboles que fueron expuestas a agua de neblina y de lluvia. Basandose en medidas de estructure del bosque y la biomasa de epífitas se derivo un modelo multi nivel de dosel, estos resultados fueron aumentados a la escala de ecosystema. El modelo fue guiado por datos meteorológicos tomados a cada hora y datos de deposición atmosféricos y las predicciónes del modelo fueron evaluadas con medidas de la lluvia indirecta (throughfall) del sitio. Las predicciónes del modelo fueron similares a los datos de campo para eventos individuales, el ciclo hidrológico anual y las fluctuaciones de N en la lluvia indirecta. La simulación de eventos individuales indicaron que las briófitas y grupos de epífitas retuvieron 33,67 por ciento de N inorganico en agua de nubes y de lluvia. Predicciónes anuales del modelo indican que los grupos de epífitas retienen 3.4 kg N ha/año, equivalente al 50 por ciento del N inorganico en la deposición atmosférica (6.8 kg N ha/año). Nuestros resultados indican que las briófitas en el dosel desempeñan un papel muy importante en la retención y ciclaje de N inorganico, porque transforman el N con alta mobilidad en N de baja mobilidad y a formas mas recalcitrantes en la biomasa, la hojarasca y el humus. [source]

Nitrogen Fixation in Bryophytes, Lichens, and Decaying Wood along a Soil-age Gradient in Hawaiian Montane Rain Forest

BIOTROPICA, Issue 1 2003
Virginia Matzek
ABSTRACT We determined rates of acetylene reduction and estimated total nitrogen fixation associated with bryophytes, lichens, and decaying wood in Hawaiian montane rain forest sites with underlying substrate ranging in age from 300 to 4.1 million years. Potential N fixation ranged from ca 0.2 kg/ha annually in the 300-year-old site to ca 1 kg/ha annually in the 150,000-year-old site. Rates of acetylene reduction were surprisingly uniform along the soil-age gradient, except for high rates in symbiotic/associative fixers at the 150,000-year-old site and in heterotrophic fixers at the 2100-year-old site. Low fixation at the youngest site, where plant production is known to be N-limited, suggests that demand for N alone does not govern N fixation. Total N fixation was highest in sites with low N:P ratios in leaves and stem wood, perhaps because epiphytic bryophytes and lichens depend on canopy leachate for mineral nutrients and because heterotrophic fixation is partly controlled by nutrient supply in the decomposing substrate; however, differences in substrate cover, rather than in fixation rates, had the largest effect on the total N input from fixation at these sites. [source]