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Montane Rain Forest (montane + rain_forest)
Selected AbstractsTree Diversity, Forest Structure and Productivity along Altitudinal and Topographical Gradients in a Species-Rich Ecuadorian Montane Rain ForestBIOTROPICA, Issue 2 2010Jürgen Homeier ABSTRACT We studied the spatial heterogeneity of tree diversity, and of forest structure and productivity in a highly diverse tropical mountain area in southern Ecuador with the aim of understanding the causes of the large variation in these parameters. Two major environmental gradients, elevation and topography, representing a broad range of climatic and edaphic site conditions, were analyzed. We found the highest species richness of trees in valleys <2100 m. Valleys showed highest values of basal area, leaf area index and tree basal area increment as well. Tree diversity also increased from ridges to valleys, while canopy openness decreased. Significant relationships existed between tree diversity and soil parameters (pH, total contents of Mg, K, Ca, N and P), and between diversity and the spatial variability of pH and Ca and Mg contents suggesting a dependence of tree diversity on both absolute levels and on the small-scale heterogeneity of soil nutrient availability. Tree diversity and basal area increment were positively correlated, partly because both are similarly affected by soil conditions. We conclude that the extraordinarily high tree species richness in the area is primarily caused by three factors: (1) the existence of steep altitudinal and topographic gradients in a rather limited area creating a small-scale mosaic of edaphically different habitats; (2) the intermingling of Amazonian lowland plant species, that reach their upper distribution limits, and of montane forest species; and (3) the geographical position of the study area between the humid eastern Andean slope and the dry interandean forests of South Ecuador. [source] Fine Root Distribution in a Lower Montane Rain Forest of PanamaBIOTROPICA, Issue 3 2009Dirk Hölscher ABSTRACT In a Panamanian lower montane rain forest we: (1) analyzed the vertical and horizontal distribution of fine roots; and (2) assessed the relationship of fine root mass to thickness of the soil organic layer, soil pH, and soil-extractable nitrogen. The soil in the study area has developed on volcanic ash deposits and was classified as Hapludand. In randomly distributed samples, the median fine root mass (biomass and necromass, diam , 2 mm) to a depth of 100 cm mineral soil was 544 g/m2, 41 percent of which was found in the organic layer. Fine root mass was approximately twice as high in the vicinity of stems of the tree species Oreomunnea mexicana (1069 g/m2) and the palm species Colpothrinax aphanopetala (1169 g/m2) and was associated with thick organic layers. The median thickness of the soil organic layer in a larger random sample (N= 64) was 8 cm with a considerable variation (interquartile range: 7 cm). In these samples, the density of fine root biomass was correlated with the concentration of extractable nitrogen (r= 0.33, P= 0.011), and on an areal basis, fine root biomass in the organic layer increased with increasing thickness of the organic layer (r= 0.63, P < 0.001) and decreasing pHKCl (r=,0.33, P < 0.01). Fine root biomass in the upper mineral soil did not show significant correlations with any of the studied parameters. RESUMEN En un bosque panameño bajo montano tropical (1) analizamos la distribución horizontal y vertical de las raíces finas, y (2) evaluamos la relación de la masa de las raíces finas con el espesor de la capa de suelo orgánico, pH del suelo, y nitrógeno extraíble del suelo. El suelo del área de estudio se ha desarrollado en depósitos de ceniza volcánica y fue clasificado como Hapludand. En muestras distribuidas aleatoriamente, la media de la masa de raíces finas (biomasa y masa necrosada, diámetro , 2 mm) a una profundidad de 100 cm del suelo mineral fue 544 g/m2, 41 por ciento de las cuales fueron encontradas en suelo orgánico. La masa de raíces finas fue aproximadamente el doble en la vecindad entre los pies de especies de árboles Oreomunnea mexicana (1069 g/m2) y especies de palmera Colpothrinax aphanopetala (1169 g/m2) y fue asociada con el espesor de capa orgánica. El espesor mediano de la capa de suelo orgánico en una amplia muestra aleatoria (N= 64) fue 8 cm con una considerable variación (intervalo entre cuartilas: 7 cm). En estas muestras, la densidad de raíces finas fue correlacionada con la concentración de nitrógeno extraíble (r= 0.33, P= 0.011), y en base al área, la biomasa de raíces finas en la capa orgánica aumentó con el incremento del espesor de la capa orgánica (r= 0.63, P < 0.001) y decrecimiento del pHKCl (r=,0.33, P < 0.01). La biomasa de raíces finas en el suelo mineral superior no mostró ninguna significante correlación con los parámetros estudiados. [source] Nitrogen Fixation in Bryophytes, Lichens, and Decaying Wood along a Soil-age Gradient in Hawaiian Montane Rain ForestBIOTROPICA, Issue 1 2003Virginia 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] Nutrient storage and turnover in organic layers under tropical montane rain forest in EcuadorEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 1 2002W. Wilcke Summary In tropical montane forests nutrients released from the organic layers of the soil can supply a large part of the vegetation's requirements. We have examined concentrations, storage, and turnover times of nutrients in the organic layer and the fluxes of nutrients by the fall of small litter (leaves, seeds, flowers, small twigs, and plant debris that passed an opening of 0.3 m × 0.3 m) in such a forest in Ecuador. The times taken for litter to turn over were estimated by relating nutrient storage in the organic layer to rate of litterfall and by incubating samples in the laboratory. The organic layer had a thickness of 2,43 cm, a mass of 30,713 t ha,1, and a nutrient storage of 0.87,21 t N, 0.03,0.70 t P, 0.12,2.5 t K, 0.09,3.2 t Ca, and 0.07,1.0 t Mg ha,1. The pH (in H2O) ranged between 3.1 and 7.4 and was correlated with the concentrations of Ca and Mg (r=,0.83 and 0.84, respectively). The quantity of small litter (8.5,9.7 t year,1) and mean concentrations of nutrients in litter (19,22 g N, 0.9,1.6 g P, 6.1,9.1 g K, 12,18 g Ca, and 3.5,5.8 g Mg kg,1) were larger than in many other tropical montane forests. The mean turnover times of elements in the organic layer increased in the order, Mg (7.0 years) < Ca (7.9) < K (8.5) < P (11) < N (14) < S (15) when calculated as the quotient of storage in the organic layer to flux by litterfall; they were <,12 years for N, P, and S in the incubation experiment. Under optimum conditions in the laboratory, the mineralization of S was just as large as the S deposition by litterfall. In weakly acid soils Mn and Zn and in strongly acid soils Ca added in a nutrient solution were immobilized during incubation. Thus, lack of S, Mn, Zn, and Ca might limit plant growth on some soils. [source] Bergmann's rule does not apply to geometrid moths along an elevational gradient in an Andean montane rain forestGLOBAL ECOLOGY, Issue 1 2004Gunnar Brehm ABSTRACT Aim, Bergmann's rule generally predicts larger animal body sizes with colder climates. We tested whether Bergmann's rule at the interspecific level applies to moths (Lepidoptera: Geometridae) along an extended elevational gradient in the Ecuadorian Andes. Location, Moths were sampled at 22 sites in the province Zamora-Chinchipe in southern Ecuador in forest habitats ranging from 1040 m to 2677 m above sea level. Methods, Wingspans of 2282 male geometrid moths representing 953 species were measured and analysed at the level of the family Geometridae, as well as for the subfamily Ennominae with the tribes Boarmiini and Ourapterygini, and the subfamily Larentiinae with the genera Eois, Eupithecia and Psaliodes. Results, Bergmann's rule was not supported since the average wingspan of geometrid moths was negatively correlated with altitude (r = ,0.59, P < 0.005). The relationship between body size and altitude in Geometridae appears to be spurious because species of the subfamily Larentiinae are significantly smaller than species of the subfamily Ennominae and simultaneously increase in their proportion along the gradient. A significant decrease of wingspan was also found in the ennomine tribe Ourapterygini, but no consistent body size patterns were found in the other six taxa studied. In most taxa, body size variation increases with altitude, suggesting that factors acting to constrain body size might be weaker at high elevations. Main conclusions, The results are in accordance with previous studies that could not detect consistent body size patterns in insects at the interspecific level along climatic gradients. [source] Carbon and nutrient limitation of soil microorganisms and microbial grazers in a tropical montane rain forestOIKOS, Issue 6 2010Valentyna Krashevska We investigated the role of carbon, nitrogen and phosphorus as limiting factors of microorganisms and microbial grazers (testate amoebae) in a montane tropical rain forest in southern Ecuador. Carbon (as glucose), nitrogen (as NH4NO3) and phosphorus (as NaH2PO4) were added separately and in combination bimonthly to experimental plots for 20 months. By adding glucose and nutrients we expected to increase the growth of microorganisms as the major food resource of testate amoebae. The response of microorganisms to experimental treatments was determined by analysing microbial biomass (SIR), fungal biomass and microbial community composition as measured by phospholipid fatty acids (PLFAs). We hypothesized that the response of testate amoebae is closely linked to that of microorganisms. Carbon addition strongly increased ergosterol concentration and, less pronounced, the amount of linoleic acid as fungal biomarker, suggesting that saprotrophic fungi are limited by carbon. Microbial biomass and ergosterol concentrations reached a maximum in the combined treatment with C, N and P indicating that both N and P also were in short supply. In contrast to saprotrophic fungi and microorganisms in total, testate amoebae suffered from the addition of C and reached maximum density by the addition of N. The results indicate that saprotrophic fungi in tropical montane rain forests are mainly limited by carbon whereas gram positive and negative bacteria benefit from increased availability of P. Testate amoebae suffered from increased dominance of saprotrophic fungi in glucose treatments but benefited from increased supply of N. The results show that testate amoebae of tropical montane rain forests are controlled by bottom,up forces relying on specific food resources rather than the amount of bacterial biomass with saprotrophic fungi functioning as major antagonists. Compared to temperate systems microbial food webs in tropical forests therefore may be much more complex than previously assumed with trophic links being rather specific and antagonistic interactions overriding trophic interactions. [source] Fine Root Distribution in a Lower Montane Rain Forest of PanamaBIOTROPICA, Issue 3 2009Dirk Hölscher ABSTRACT In a Panamanian lower montane rain forest we: (1) analyzed the vertical and horizontal distribution of fine roots; and (2) assessed the relationship of fine root mass to thickness of the soil organic layer, soil pH, and soil-extractable nitrogen. The soil in the study area has developed on volcanic ash deposits and was classified as Hapludand. In randomly distributed samples, the median fine root mass (biomass and necromass, diam , 2 mm) to a depth of 100 cm mineral soil was 544 g/m2, 41 percent of which was found in the organic layer. Fine root mass was approximately twice as high in the vicinity of stems of the tree species Oreomunnea mexicana (1069 g/m2) and the palm species Colpothrinax aphanopetala (1169 g/m2) and was associated with thick organic layers. The median thickness of the soil organic layer in a larger random sample (N= 64) was 8 cm with a considerable variation (interquartile range: 7 cm). In these samples, the density of fine root biomass was correlated with the concentration of extractable nitrogen (r= 0.33, P= 0.011), and on an areal basis, fine root biomass in the organic layer increased with increasing thickness of the organic layer (r= 0.63, P < 0.001) and decreasing pHKCl (r=,0.33, P < 0.01). Fine root biomass in the upper mineral soil did not show significant correlations with any of the studied parameters. RESUMEN En un bosque panameño bajo montano tropical (1) analizamos la distribución horizontal y vertical de las raíces finas, y (2) evaluamos la relación de la masa de las raíces finas con el espesor de la capa de suelo orgánico, pH del suelo, y nitrógeno extraíble del suelo. El suelo del área de estudio se ha desarrollado en depósitos de ceniza volcánica y fue clasificado como Hapludand. En muestras distribuidas aleatoriamente, la media de la masa de raíces finas (biomasa y masa necrosada, diámetro , 2 mm) a una profundidad de 100 cm del suelo mineral fue 544 g/m2, 41 por ciento de las cuales fueron encontradas en suelo orgánico. La masa de raíces finas fue aproximadamente el doble en la vecindad entre los pies de especies de árboles Oreomunnea mexicana (1069 g/m2) y especies de palmera Colpothrinax aphanopetala (1169 g/m2) y fue asociada con el espesor de capa orgánica. El espesor mediano de la capa de suelo orgánico en una amplia muestra aleatoria (N= 64) fue 8 cm con una considerable variación (intervalo entre cuartilas: 7 cm). En estas muestras, la densidad de raíces finas fue correlacionada con la concentración de nitrógeno extraíble (r= 0.33, P= 0.011), y en base al área, la biomasa de raíces finas en la capa orgánica aumentó con el incremento del espesor de la capa orgánica (r= 0.63, P < 0.001) y decrecimiento del pHKCl (r=,0.33, P < 0.01). La biomasa de raíces finas en el suelo mineral superior no mostró ninguna significante correlación con los parámetros estudiados. [source] Soil Phosphorus Fractionation during Forest Development on Landslide Scars in the Luquillo Mountains, Puerto Rico,BIOTROPICA, Issue 1 2002Jacqueline Frizano ABSTRACT Mineral soils from a chronosequence of landslide scars ranging in age from 1 to more than 55 years in a subtropical montane rain forest of eastern Puerto Rico were used to determine the rate at which labile P capital recovers during primary succession. Nine organic and inorganic soil P fractions were measured using the Hedley sequential extraction procedure. Deep soil cores (9 m) from a nearby site were also analyzed to determine the distribution of P fractions below the solum. Litterfall P was measured for two years in the landslide scars to estimate allochthonous litter P inputs, and published precipitation data were used to estimate annual atmospheric inputs of P to the recovering forests. In the upper solum (0,10 cm), organic matter increased with landslide age, as did resin-Pi, labile P (defined here as resin-Pi + HCO3 -Pi + HCO3 -Po) and total organic P. Occluded P decreased with increasing landslide age. No significant changes in P concentrations or pools were observed in 10 to 35 or in 35 to 60 cm depth intervals across the chronosequence. Labile soil P increased to approximately two-thirds of the pre-disturbance levels in the oldest landslide scar (>55 yr). Thus, plants, their associated microflora/fauna, and P inputs from off-site substantially altered the distribution of soil P fractions during forest recovery. Across the chronosequence, the increase in labile P accumulated in soil and biomass appeared to be greater than the estimated allochthonous inputs from litter and precipitation, indicating that as the forest developed, some occluded P may have been released for use by soil biota. Resin-Pi and labile P were correlated with soil organic matter content, suggesting, as in other highly weathered soils, organic matter accumulation and turnover are important in maintaining labile P pools. Primary mineral P (apatite) was scarce, even in deep soil cores. [source] Diversity and composition of Arctiidae moth ensembles along a successional gradient in the Ecuadorian AndesDIVERSITY AND DISTRIBUTIONS, Issue 5 2005Nadine Hilt ABSTRACT Andean montane rain forests are among the most species-rich terrestrial habitats. Little is known about their insect communities and how these respond to anthropogenic habitat alteration. We investigated exceptionally speciose ensembles of nocturnal tiger moths (Arctiidae) at 15 anthropogenically disturbed sites, which together depict a gradient of forest recovery and six closed-forest understorey sites in southern Ecuador. At weak light traps we sampled 9211 arctiids, representing 287 species. Arctiid abundance and diversity were highest at advanced succession sites, where secondary scrub or young forest had re-established, followed by early succession sites, and were lowest, but still high, in mature forest understorey. The proportion of rare species showed the reverse pattern. We ordinated moth samples by non-metric multidimensional scaling using the chord-normalized expected species shared index (CNESS) index at various levels of the sample size parameter m. A distinct segregation of arctiid ensembles at succession sites from those in mature forest consistently emerged only at high m -values. Segregation between ensembles of early vs. late succession stages was also clear at high m values only, and was rather weak. Rare species were responsible for much of the faunal difference along the succession gradient, whereas many common arctiid species occurred in all sites. Matrix correlation tests as well as exploration of relationships between ordination axes and environmental variables revealed the degree of habitat openness, and to a lesser extent, elevation, as best predictors of faunal dissimilarity. Faunal differences were not related to geographical distances between sampling sites. Our results suggest that many of the more common tiger moths of Neotropical montane forests have a substantial recolonization potential at the small spatial scale of our study and accordingly occur also in landscape mosaics surrounding nature reserves. These species contribute to the unexpectedly high diversity of arctiid ensembles at disturbed sites, whereas the proportion of rare species declines outside mature forest. [source] Geographic distribution and population size of the mountain tapir (Tapirus pinchaque) in ColombiaJOURNAL OF BIOGEOGRAPHY, Issue 1 2002D. J. Lizcano Aim We conducted a study to estimate the past and present distribution and population size of T. pinchaque in Colombia. Location The study included all mountain ranges above 2000 m. Methods The past distribution was obtained by plotting on a map of past distribution of montane rain forests, the geographical locations with the name `danta' or `tapir' above 2000 m obtained from topographic maps, the locations cited in bibliographic references, and the results of interviews in the 530 Andean municipalities. The present distribution was obtained by plotting the present distribution of montane rain forests, the results of interviews and ground control. Population size was estimated by combining measurements of population density with maps of present distribution. Results In the past, the species occurred in the central and eastern Cordilleras, as well as in the Andean Massive where the three cordilleras merge in the south of the country. Currently, the species occurs in the central Andes south of Nevados National Park, and in the eastern Andes, south of Paramo de Sumapaz, Bogotá. According to our most optimistic estimates, there are about 2500 tapirs in the Andes of Colombia. Main conclusions These individuals occur in a total of thirty-five forest patches that range from 5 to 3700 km2. Only five to six fragments have the minimum necessary size (826 km2) to maintain at least 150 individuals, the estimated number to maintain viable population in the short term. The populations most threatened are those of the central Cordillera between P.N. Las Hermosas and P.N. Nevado del Huila where large tracts of mature montane forests are being converted to opium fields. [source] | ||||||||||