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Montane Forest (montane + forest)
Kinds of Montane Forest Selected AbstractsComparing the Dispersal of Large-seeded Tree Species by Frugivore Assemblages in Tropical Montane Forest in AfricaBIOTROPICA, Issue 4 2009Nicole D. Gross-Camp ABSTRACT We examined frugivore visitation and seed dispersal of five large-seeded (, 5 mm) tree species in tropical montane forest based on their occurrence in frugivorous primate diets: Ekebergia capensis, Olea capensis, Parinari excelsa, Prunus africana, and Syzygium guineense. A total of 21 frugivores in five assemblages (i.e., chimpanzees, cercopithecines, large-bodied birds, small-bodied birds, and squirrels) were observed over the study period (August 2006 and October,April 2007). We observed seed dispersal in four of five tree species studied; no dispersal was observed for P. excelsa. Frugivore assemblages did not visit tree species equally. Primates spent the most time in trees and had the largest group size. Large-bodied birds (LB) and chimpanzees dispersed the highest number of seeds per minute. LB and cercopithecines potentially dispersed the greatest number of seeds for E. capensis, and chimpanzees for S. guineense. Our analyses indicated that the mean fruiting duration of the focal tree, time in the tree, and number of species present are important predictor variables for seed dispersal by small- and large-bodied birds, and cercopithecines. The number of fruiting trees in the immediate vicinity of the focal tree further predicted seed dispersal for small-bodied birds (SB). Large-bodied birdseed dispersal also was predicted by time in tree by SB, and the number of individuals for SB and cercopithecines. Cercopithecines (CS) were further explained by the time in tree and number of species (SB & LB), and number of individuals for CS. Our study highlights the complexity of describing the relative importance of a frugivore assemblage to the dispersal of a tree species seeds. [source] Retention of Inorganic Nitrogen by Epiphytic Bryophytes in a Tropical Montane Forest,BIOTROPICA, Issue 3 2005Kenneth 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] The Influence of Topography on Tree Growth, Mortality, and Recruitment in a Tropical Montane Forest,BIOTROPICA, Issue 3 2000P. J. Bellingham ABSTRACT To determine if there were consistent differences in growth, mortality, and recruitment on slopes and ridge crests in tropical montane forests, which could explain the (frequent but not universal) low stature of trees in the ridgetop forests, we analyzed data from long-term plots in Jamaica (1990,1994; sixteen 200-m2 plots, six on ridge crests and five each on north and south slopes). Mortality was higher on north slopes, while growth and recruitment rates were not significantly different among positions. Soil pH and effects of recent disturbance by Hurricane Gilbert were positively correlated with growth and recruitment, while slope angle and disturbance effects were the best predictors of mortality. The patterns we found in Jamaica, that growth and recruitment were not higher on ridge crests than slopes, are different than those found by Herwitz and Young in Australia where growth and turnover were greater on a ridge crest. Therefore, it is not possible at present to make simple generalizations about dynamics of ridge crest versus slope forests in the montane tropics. [source] Nest Selection by Cavity-nesting Birds in Subtropical Montane Forests of the Andes: Implications for Sustainable Forest ManagementBIOTROPICA, Issue 3 2009Natalia Politi ABSTRACT Development of sustainable forestry has been hampered in tropical countries by a scarcity of research on the ecological effects of logging. We focused on cavity-nesting birds, a group known to be sensitive to logging. Cavities used for nesting were not a random subset of all available suitable cavities. Birds selected cavities that were relatively high above the ground, had smaller entrances, and were excavated by woodpeckers. The use of tree species was also not random: Calycophyllum multiflorum, Blepharocalyx gigantea, and Podocarpus parlatorei were disproportionately important. Cavity nests were also more likely to be found in areas with trees with high mean diameter at breast height. This study emphasizes the need to maintain some unlogged forest patches within logging areas and retain certain species of trees. This study has implications for forest management in Argentina, where a new law mandates the sustainable use of forest resources and where many landowners are interested in forest certification. RESUMEN En los países tropicales la implementación del manejo forestal sostenible se ha visto limitado debido a la escasez de estudios sobre los efectos ecológicos de la explotación forestal. Nos focalizamos en aves que nidifican en huecos de árboles porque este es un grupo sensible a las prácticas de manejo forestal. Los huecos en árboles utilizados para nidificar no fueron un conjunto al azar de todos los huecos adecuados disponibles. Las aves seleccionaron huecos en árboles que estaban a una altura elevada desde el suelo, con entradas chicas y excavadas por carpinteros. El uso de las especies de árboles tampoco fue al azar: Calycophyllum multiflorum, Blepharocalyx gigantea y Podocarpus parlatorei fueron desproporcionadamente importantes. Fue más probable encontrar nidos en parches de árboles que tuvieron un promedio de diámetro a la altura del pecho más alto. Este estudio resalta la necesidad de retener algunos parches del bosque sin intervención dentro del área de manejo y retener ciertas especies arbóreas. Este estudio tiene implicancias en el manejo forestal en Argentina, donde una nueva ley plantea un uso sostenible de los recursos forestales y donde muchos propietarios están interesados en obtener una certificación forestal. [source] Size and Structure of Fine Root Systems in Old-growth and Secondary Tropical Montane Forests (Costa Rica)BIOTROPICA, Issue 2 2003Dietrich Hertel ABSTRACT The fine root systems of three tropical montane forests differing in age and history were investigated in the Cordillera Talamanca, Costa Rica. We analyzed abundance, vertical distribution, and morphology of fine roots in an early successional forest (10,15 years old, ESF), a mid-successional forest (40 years old, MSP), and a nearby undisturbed old-growth forest (OGF), and related the root data to soil morphological and chemical parameters. The OGF stand contained a 19 cm deep organic layer on the forest floor (i.e., 530 mol C/m2), which was two and five times thicker than that of the MSF (10 cm) and ESF stands (4 cm), respectively. There was a corresponding decrease in fine root biomass in this horizon from 1128 g dry matter/m2 in the old-growth forest to 337 (MSF) and 31 g/m2 (ESF) in the secondary forests, although the stands had similar leaf areas. The organic layer was a preferred substrate for fine root growth in the old-growth forest as indicated by more than four times higher fine root densities (root mass per soil volume) than in the mineral topsoil (0,10 cm); in the two secondary forests, root densities in the organic layer were equal to or lower than in the mineral soil. Specific fine root surface areas and specific root tip abundance (tips per unit root dry mass) were significantly greater in the roots of the ESF than the MSF and OGF stands. Most roots of the ESF trees (8 abundant species) were infected by VA mycorrhizal fungi; ectomycorrhizal species (Quercus copeyemis and Q. costaricensis) were dominant in the MSF and OGF stands. Replacement of tropical montane oak forest by secondary forest in Costa Rica has resulted in (1) a large reduction of tree fine root biomass; (2) a substantial decrease in depth of the organic layer (and thus in preferred rooting space); and (3) a great loss of soil carbon and nutrients. Whether old,growth Quercus forests maintain a very high fine root biomass because their ectomycorrhizal rootlets are less effective in nutrient absorption than those of VA mycorrhizal secondary forests, or if their nutrient demand is much higher than that of secondary forests (despite a similar leaf area and leaf mass production), remains unclear. [source] Long-term reproductive behaviour of woody plants across seven Bornean forest types in the Gunung Palung National Park (Indonesia): suprannual synchrony, temporal productivity and fruiting diversityECOLOGY LETTERS, Issue 10 2007Charles H. Cannon Abstract For 68 months, we observed the reproductive behaviour of 7288 woody plants (172 figs, 1457 climbers and 5659 trees) spanning major soil and elevational gradients. Two 2,3 month community-wide supra-annual fruiting events were synchronized across five forest types, coinciding with ENSO events. At least 27 genera in 24 families restricted their reproduction to these events, which involved a substantial proportion of tree diversity (> 80% of phylogenetic diversity). During these events, mean reproductive levels (8.5%) represented an almost four-fold increase compared with other months. These patterns indicate a strong behavioural advantage to this unusual reproductive behaviour. Montane forest experienced a single, separate fruiting peak while the peat swamp forest did not participate. Excluding these events, no temporal reproductive pattern was detectible, at either the landscape or forest type. These phenological patterns have major implications for the conservation of frugivore communities, with montane and swamp forests acting as ,keystone' forests. [source] Counting elephants in Montane forests: some sources of errorAFRICAN JOURNAL OF ECOLOGY, Issue 2 2009Hilde Vanleeuwe Abstract The dung count method is widely used to estimate elephant numbers in forests. It was developed in the lowland forests of Central Africa but it is also used in Montane forests in eastern Africa. Using data collected on Mount Kenya and computer simulations, this paper explores the following issues associated with dung surveys in Montane forests: ,,High rainfall at 3000 m altitude on Mount Kenya was expected to accelerate dung pile decay but no significant difference was found between 3000 and 2500 m where less rain falls, possibly because high rainfall at 3000 m is counteracted by lower temperatures; ,,Physical obstacles make it difficult to walk long, straight transects in Montane forests. Deviating from a straight line pushes the distribution of distance measurements from dung piles to the transect centre line (pdist) towards a negative exponential (NE), which complicates data analysis and may give inaccurate estimates. Using short transects largely alleviate this problem; ,,Analysis of dung count simulations shows that the expected sightability curve of pdist pushes towards a NE with increasing numbers of obstacles blocking the view, even along perfectly straight transects; ,,Extrapolating measured dung density to map area on Mount Kenya resulted in an underestimate of c. 13%. An unstratified correction of map area to ground area for Montane areas would be biased because of the strong tendency for elephants to avoid steeply sloping areas. Résumé La méthode par comptage des crottes est largement utilisée pour estimer le nombre des éléphants en forêt. Elle a été mise au point dans les forêts de basse altitude d'Afrique centrale, mais elle est aussi employée dans les forêts de montagne d'Afrique de l'Est. Utilisant les données collectées sur le Mont Kenya et des simulations informatiques, cet article explore les questions suivantes liées au comptage des crottes dans les forêts de montagne: ,,Les fortes chutes de pluies à 3 000 mètres d'altitude sur le Mont Kenya étaient censées accélérer la décomposition des tas de crottes, mais on n'a pas trouvé de différence significative entre 3 000 et 2 500 mètres où il tombe moins de pluie, peut-être parce que les fortes pluies à 3 000 mètres sont compensées par de plus basses températures; ,,Les obstacles physiques rendent plus difficiles de marcher le long de transects rectilignes dans les forêts de montagne. Le fait de dévier de la ligne droite pousse la distribution des mesures des distances entre les tas de crottes et la ligne droite du transect (pdist) vers un modèle exponentiel négatif (EN) qui complique l'analyse des données et peut donner des estimations inexactes. Le fait de recourir à des transects courts réduit considérablement ce problème; ,,L'analyse des simulations de comptages de crottes montre que la courbe de visibilité attendue de pdist pousse vers un EN lorsque le nombre d'obstacles bloquant la vue augmente, même le long de transects parfaitement rectilignes; ,,L'extrapolation de la densité mesurée des crottes sur une carte du Mont Kenya a abouti à une sous-estimation d'environ 13%. Une correction non stratifiée de la surface cartographiée des zones montagneuses vers une surface plane serait biaisée étant donné que les éléphants ont fortement tendance àéviter les zones escarpées et glissantes. [source] Nutrients, diversity, and community structure of two phytotelm systems in a lower montane forest, Puerto RicoECOLOGICAL ENTOMOLOGY, Issue 3 2000Barbara A. Richardson Summary 1. Bromeliad and heliconia phytotelmata in the same forest area were compared in terms of their animal assemblages, nutrient inputs, and plant architecture. 2. For all major elements, nutrient inputs from canopy-derived debris and rainfall in bromeliads were significantly lower than those derived from decaying flower parts and plant secretions in heliconia bracts. Bromeliads contained significantly fewer organisms per unit volume of water and unit dry weight of organic matter than did heliconia inflorescences. They also contained a significantly lower animal biomass (199 mg DW from 15 bromeliads, 527 mg DW from 15 heliconia inflorescences). 3. Species richness was independent of abundance, demonstrating that, at least for small container habitats, higher abundance does not necessarily lead to a greater species richness. Communities were remarkably similar in patterns of relative abundance and species richness (23 spp. in bromeliads, 21 spp. in heliconia), probably due to functional similarities in plant architecture, with the two most abundant species comprising 60,62% of the total community. Coefficients of similarity were low because of marked differences in species assemblages. 4. Some taxa were phytotelm generalists but most showed a preference for one particular habitat, indicating differential selection in the choice of oviposition sites and larval development within the forest ecosystem. In common with many island communities, species richness was lower than that reported for these phytotelm habitats in mainland central and south America. [source] Assessing factors that influence spatial variations in duff moistureHYDROLOGICAL PROCESSES, Issue 15 2008L. D. Raaflaub Abstract Patterns and spatial variations in the moisture of the decomposing organic matter on the forest floor (the duff) of a montane forest were analysed in an effort to determine the primary factors shaping these patterns. Above and below canopy meteorological conditions were monitored to determine the influence of canopy cover on duff moisture. The spatial and temporal distributions of duff moisture were assessed through daily duff moisture measurements collected at regular intervals in ten 10 × 10 m plots representing a variety of canopy types and densities. Meteorological conditions ranged from very wet to very dry and resulted in duff moisture variations that were more pronounced during wet periods than in extended periods of drying. Investigations on the influence of canopy type, tree density, and tree proximity on duff moisture patterns indicated that canopy type and tree proximity are the most important factors affecting duff moisture. Interception seems to be the primary controller of duff moisture patterns with an influence at the centimetre scale. Copyright © 2008 John Wiley & Sons, Ltd. [source] Rainfall interception in a lower montane forest in Ecuador: effects of canopy propertiesHYDROLOGICAL PROCESSES, Issue 7 2005Katrin Fleischbein Abstract Rainfall interception in forests is influenced by properties of the canopy that tend to vary over small distances. Our objectives were: (i) to determine the variables needed to model the interception loss of the canopy of a lower montane forest in south Ecuador, i.e. the storage capacity of the leaves S and of the trunks and branches St, and the fractions of direct throughfall p and stemflow pt; (ii) to assess the influence of canopy density and epiphyte coverage of trees on the interception of rainfall and subsequent evaporation losses. The study site was located on the eastern slope of the eastern cordillera in the south Ecuadorian Andes at 1900,2000 m above sea level. We monitored incident rainfall, throughfall, and stemflow between April 1998 and April 2001. In 2001, the leaf area index (LAI), inferred from light transmission, and epiphyte coverage was determined. The mean annual incident rainfall at three gauging stations ranged between 2319 and 2561 mm. The mean annual interception loss at five study transects in the forest varied between 591 and 1321 mm, i.e. between 25 and 52% of the incident rainfall. Mean S was estimated at 1·91 mm for relatively dry weeks with a regression model and at 2·46 mm for all weeks with the analytical Gash model; the respective estimates of mean St were 0·04 mm and 0·09 mm, of mean p were 0·42 and 0·63, and of mean pt were 0·003 and 0·012. The LAI ranged from 5·19 to 9·32. Epiphytes, mostly bryophytes, covered up to 80% of the trunk and branch surfaces. The fraction of direct throughfall p and the LAI correlated significantly with interception loss (Pearson's correlation coefficient r = ,0·77 and 0·35 respectively, n = 40). Bryophyte and lichen coverage tended to decrease St and vascular epiphytes tended to increase it, although there was no significant correlation between epiphyte coverage and interception loss. Our results demonstrate that canopy density influences interception loss but only explains part of the total variation in interception loss. Copyright © 2004 John Wiley & Sons, Ltd. [source] Elevation and forest clearing effects on foraging differ between surface , and subterranean , foraging army ants (Formicidae: Ecitoninae)JOURNAL OF ANIMAL ECOLOGY, Issue 1 2009Anjali Kumar Summary 1Forest fragmentation often results in a matrix of open areas mixed with patches of forest. Both biotic and abiotic factors can affect consumer species' ability to utilize the altered habitat, especially for species that range over large areas searching for prey. 2Army ants (Formicidae: Ecitoninae) are highly mobile top predators in terrestrial Neotropical ecosystems. Army ant foraging behaviour is influenced by forest clearing at lowland sites, and clearing can reduce army ant population persistence. 3Because high temperatures are implicated in hindering above-ground army ant foraging, we predicted that forest clearing effects on army ant foraging would be reduced at higher (cooler) elevations in montane forest. We also predicted that subterranean foraging, employed by some army ant species, would buffer them from the negative effects of forest clearing. 4We quantified the foraging rates of above-ground and underground foraging army ants at eight sites along an elevational gradient from 1090 to 1540 m a.s.l. We asked whether these two foraging strategies cause a difference in the ability of army ants to forage in open matrix areas relative to elevationally matched forested habitats, and whether elevation predicts open area vs. forest foraging rate differences. 5As predicted, army ants that forage above-ground had lower foraging rates in open areas, but the open area vs. forest difference declined with elevation. In contrast, underground foragers were not affected by habitat type, and underground foraging rates increased with elevation. Ground surface temperatures were higher in open areas than forested areas. Temperatures declined with elevation, and temperature differences between open and forested areas decreased with elevation. 6We conclude that army ants that forage above-ground may be restricted to forested areas due to a thermal tolerance threshold, but that they are released from this limitation at higher elevations. We further suggest that underground foraging permits some army ants to persist within modified landscapes. Our findings have implications for the effects of habitat modification and climate change on these top predators. [source] Fire regimes and forest changes in mid and upper montane forests of the southern Cascades, Lassen Volcanic National Park, California, U.S.A.JOURNAL OF BIOGEOGRAPHY, Issue 1 2000A. H. Taylor Abstract Aim Spatial and temporal variation in fire regime parameters and forest structure were assessed. Location A 2630-ha area of mid- and upper montane forest in Lassen Volcanic National Park (LVNP). Methods Two hypotheses were tested concerned with fire-vegetation relationships in southern Cascades forests: (1) fire regime parameters (return interval, season of burn, fire size, rotation period) vary by forest dominant, elevation and slope aspect; and (2) fire exclusion since 1905 has caused forest structural and compositional changes in both mid- and upper montane forests. The implications of the study for national park management are also discussed. Results Fire regime parameters varied by forest compositional group and elevation in LVNP. Median composite and point fire return intervals were shorter in low elevation Jeffrey pine (Pinus jeffreyi) (JP) (4,6 years, 16 years) and Jeffrey pine,white fir (Abies concolor) (JP-WF) (5,10 years, 22 years) and longer in high elevation red fir (Abies magnifica), western white pine (Pinus monticola) (RF-WWP) forests (9,27 years, 70 years). Median fire return intervals were also shorter on east-facing (6,9 years, 16.3 years) and longer on south- (11 years, 32.5 years) and west-facing slopes (22,28 years, 54-years) in all forests and in each forest composition group. Spatial patterns in fire rotation length were the same as those for fire return intervals. More growing season fires also occurred in JP (33.1%) and JP-WF (17.5%) than in RF-WWP (1.1%) forests. A dramatic decline in fire frequency occurred in all forests after 1905. Conclusions Changes in forest structure and composition occurred in both mid- and upper montane forests due to twentieth-century fire exclusion. Forest density increased in JP and JP-WF forests and white fir increased in JP-WF forests and is now replacing Jeffrey pine. Forest density only increased in some RF-WWP stands, but not others. Resource managers restoring fire to these now denser forests need to burn larger areas if fire is going to play its pre-settlement role in montane forest dynamics. [source] Abiotic and biotic drivers of seedling survival in a hurricane-impacted tropical forestJOURNAL OF ECOLOGY, Issue 6 2009Liza S. Comita Summary 1. ,Many forests experience periodic, large-scale disturbances, such as hurricanes and cyclones, which open the forest canopy, causing dramatic changes in understorey light conditions and seedling densities. Thus, in hurricane-impacted forests, large variations in abiotic and biotic conditions likely shape seedling dynamics, which in turn will contribute to patterns of forest recovery. 2. ,We monitored 13 836 seedlings of 82 tree and shrub species over 10 years following Hurricane Georges in 1998 in a subtropical, montane forest in Puerto Rico. We quantified changes in the biotic and abiotic environment of the understorey and linked seedling dynamics to changes in canopy openness and seedling density, and to spatial variation in soil type, topography and tree density. 3. ,Canopy openness was highest when first measured after Hurricane Georges and dropped significantly within c. 3 years, while seedling densities remained high for c. 5 years post-hurricane. When all species and census intervals were analysed together, generalized linear mixed effects models revealed that canopy openness, seedling and adult tree densities were significant drivers of seedling survival. 4. ,The relative importance of abiotic and biotic factors changed over time. Separate analyses for each census interval revealed that canopy openness was a significant predictor of survival only for the first census interval, with lower survival at the highest levels of canopy openness. The effect of conspecific seedling density was significant in all intervals except the first, and soil type only in the final census interval. 5. ,When grouping species into life-history guilds based on adult tree susceptibility to hurricane damage, we found clear differences among guilds in the effects of biotic and abiotic factors on seedling survival. Seedlings of hurricane-susceptible and intermediate guilds were more strongly influenced by canopy openness, while seedlings of the hurricane-resistant group were less affected by conspecific seedling density. Individual species-level analyses for 12 common species, however, showed considerable variation among species within guilds. 6. ,Synthesis. Our results suggest that hurricanes shape species composition by altering understorey conditions that differentially influence the success of seedlings. Thus, predicted increases in the intensity and frequency of hurricanes in the Caribbean will likely alter seedling dynamics and ultimately the species composition in hurricane-impacted forests. [source] Soil properties and tree growth along an altitudinal transect in Ecuadorian tropical montane forestJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 2 2008Wolfgang Wilcke Abstract In tropical montane forests, soil properties change with increasing altitude, and tree-growth decreases. In a tropical montane forest in Ecuador, we determined soil and tree properties along an altitudinal transect between 1960 and 2450 m asl. In different vegetation units, all horizons of three replicate profiles at each of eight sites were sampled and height, basal area, and diameter growth of trees were recorded. We determined pH and total concentrations of Al, C, Ca, K, Mg, Mn, N, Na, P, S, Zn, polyphenols, and lignin in all soil horizons and in the mineral soil additionally the effective cation-exchange capacity (CEC). The soils were Cambisols, Planosols, and Histosols. The concentrations of Mg, Mn, N, P, and S in the O horizons and of Al, C, and all nutrients except Ca in the A horizons correlated significantly negatively with altitude. The C : N, C : P, and C : S ratios increased, and the lignin concentrations decreased in O and A horizons with increasing altitude. Forest stature, tree basal area, and tree growth decreased with altitude. An ANOVA analysis indicated that macronutrients (e.g., N, P, Ca) and micronutrients (e.g., Mn) in the O layer and in the soil mineral A horizon were correlated with tree growth. Furthermore, lignin concentrations in the O layer and the C : N ratio in soil affected tree growth. These effects were consistent, even if the effect of altitude was accounted for in a hierarchical statistical model. This suggests a contribution of nutrient deficiencies to reduced tree growth possibly caused by reduced organic-matter turnover at higher altitudes. [source] Soil phosphorus and disturbance influence liana communities in a subtropical montane forestJOURNAL OF VEGETATION SCIENCE, Issue 3 2010Agustina Malizia Abstract Questions: What are the effects of soil, topography, treefall gaps, tree species composition, and tree density on liana species composition and total liana abundance? Location: A 6-ha permanent plot in a subtropical montane forest in northwest Argentina. Methods: Multiple regressions were used to quantify associations of liana species composition and total liana abundance with edaphic, disturbance and tree community variables. Gradients in liana and tree species composition were quantified using principal components analysis (PCA). Results: Liana species composition was correlated most strongly with soil phosphorus concentration (R2=0.55). Total liana aanased with phosphorus and the density of recent treefall gaps (R2=0.60). Conclusions: In our study area, liana composition and abundance are most strongly correlated with features of the physical environment, rather than host tree characteristics. Our results support the hypothesis that recent increases in liana abundance in mature tropical forests may be related to increased rates of gap formation. [source] Ancestry and divergence of subtropical montane forest isolates: molecular biogeography of the genus Abies (Pinaceae) in southern México and GuatemalaMOLECULAR ECOLOGY, Issue 10 2008JUAN P. JARAMILLO-CORREA Abstract The genus Abies has a complex history in southern México and Guatemala. In this region, four closely related species, Abies flinckii, A. guatemalensis, A. hickelii, and A. religiosa, are distributed in fragmented and isolated montane populations. Range-wide genetic variation was investigated across species using cytoplasmic DNA markers with contrasted inheritance. Variation at two maternally inherited mitochondrial DNA markers was low. All species shared two of the nine mitotypes detected, while the remaining seven mitochondrial DNA types were restricted to a few isolated stands. Mitochondrial genetic differentiation across taxa was high (GST = 0.933), it was not related to the taxonomic identity (amova; P > 0.05) of the populations, and it was not phylogeographically structured (GST , NST). In contrast, variation at three paternally inherited chloroplast DNA microsatellites was high. Chloroplast genetic differentiation was lower (GST = 0.402; RST = 0.547) than for mitochondrial DNA, but it was significantly related to taxonomy (amova; P < 0.001), and exhibited a significant phylogeographical structure (GST < RST). Different analyses of population structure indicated that A. flinckii was the most divergent taxon, while the remaining three species formed a relatively homogeneous group. However, a small number of the populations of these three taxa, all located at the limits of their respective ranges or in the Transverse Volcanic Belt, diverged from this main cluster. These trends suggest that the Mesoamerican Abies share a recent common ancestor and that their divergence and speciation is mainly driven by genetic drift and isolation during the warm interglacial periods. [source] Fallback foods and dietary partitioning among Pan and gorillaAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2009Juichi Yamagiwa Abstract Recent findings on the strong preference of gorillas for fruits and the large dietary overlap between sympatric gorillas and chimpanzees has led to a debate over the folivorous/frugivorous dichotomy and resource partitioning. To add insight to these arguments, we analyze the diets of sympatric gorillas and chimpanzees inhabiting the montane forest of Kahuzi-Biega National Park (DRC) using a new definition of fallback foods (Marshall and Wrangham: Int J Primatol 28 [2007] 1219,1235). We determined the preferred fruits of Kahuzi chimpanzees and gorillas from direct feeding observations and fecal analyses conducted over an 8-year period. Although there was extensive overlap in the preferred fruits of these two species, gorillas tended to consume fewer fruits with prolonged availability while chimpanzees consumed fruits with large seasonal fluctuations. Fig fruit was defined as a preferred food of chimpanzees, although it may also play a role as the staple fallback food. Animal foods, such as honey bees and ants, appear to constitute filler fallback foods of chimpanzees. Tool use allows chimpanzees to obtain such high-quality fallback foods during periods of fruit scarcity. Among filler fallback foods, terrestrial herbs may enable chimpanzees to live in small home ranges in the montane forest, whereas the availability of animal foods may permit them to expand their home range in arid areas. Staple fallback foods including barks enable gorillas to form cohesive groups with similar home range across habitats irrespective of fruit abundance. These differences in fallback strategies seem to have shaped different social features between sympatric gorillas and chimpanzees. Am J Phys Anthropol 140:739,750, 2009. © 2009 Wiley-Liss, Inc. [source] Chimpanzee seed dispersal quantity in a tropical montane forest of RwandaAMERICAN JOURNAL OF PRIMATOLOGY, Issue 11 2009Nicole D. Gross-Camp Abstract We describe chimpanzee seed dispersal in the tropical montane forest of Nyungwe National Park (NNP), Rwanda, for a total of three years from January 1998 through May 2000 and May 2006 through March 2007. Relatively few studies have examined chimpanzee seed dispersal in montane communities where there are generally fewer fruiting tree species than in lowland forests. Such studies may reveal new insights into chimpanzee seed dispersal behaviors and the role that they play in forest regeneration processes. Chimpanzees are large-bodied, highly frugivorous, and tend to deposit the seeds of both large- and small-seeded fruits they consume in a viable state. We found that chimpanzees dispersed a total of 37 fruiting species (20 families) in their feces, 35% of which were large-seeded trees (,0.5,cm). A single large-seeded tree, Syzygium guineense, was the only species to be dispersed in both wadges and feces. Based on phenological patterns of the top five large-seeded tree species found in chimpanzee feces, our results indicate that chimpanzees do not choose fruits based on their availability. There was, however, a positive relationship between the presence of Ekebergia capensis seeds in chimpanzee feces and S. guineense seeds in chimpanzee wadges and their respective fruit availabilities. Our data reveal that proportionately fewer chimpanzee fecal samples at NNP contained seeds than that reported in two other communities in the Albertine Rift including one at mid-elevation and one in montane forest. As in other chimpanzee communities, seeds of Ficus spp. were the most common genus in NNP chimpanzee feces. Our data do not support previous studies that describe Ficus spp. as a fallback food for chimpanzees and highlights an intriguing relationship between chimpanzees and the large-seeded tree species, S. guineense. Am. J. Primatol. 71:901,911, 2009. © 2009 Wiley-Liss, Inc. [source] Floristic diversity in fragmented Afromontane rainforests: Altitudinal variation and conservation importanceAPPLIED VEGETATION SCIENCE, Issue 3 2010Christine B. Schmitt Abstract Question: How does the floristic diversity of Afromontane rainforests change along an altitudinal gradient? What are the implications for conservation planning in these strongly fragmented forest areas that form part of the Eastern Afromontane Biodiversity Hotspot? Location: Bonga, southwestern Ethiopia. Methods: Based on evidence from other montane forests, we hypothesized that altitude has an effect on the floristic diversity of Afromontane rainforests in southwestern Ethiopia. To test this hypothesis, detailed vegetation surveys were carried out in 62 study plots located in four relatively undisturbed forest fragments situated at altitudes between 1600 m and 2300 m. Floristic diversity was evaluated using a combination of multivariate statistical analyses and diversity indices. Results: Ordination and indicator species analyses showed gradual variations in floristic diversity along the altitudinal gradient with a pronounced shift in species composition at ca. 1830 m. Upper montane forest (>1830 m) is characterized by high fern diversity and indicator species that are Afromontane endemics. Lower montane forest (<1830 m) exhibits a greater diversity of tree species and a higher abundance of the flagship species Coffea arabica. Conclusions: Our results provide crucial ecological background information concerning the montane rainforests of Ethiopia, which have been poorly studied until now. We conclude that both forest types identified during this study need to be considered for conservation because of their particular species compositions. Owing to the high degree of forest fragmentation, conservation concepts should consider a multi-site approach with at least two protected areas at different altitudinal levels. [source] Seed plants of Fiji: an ecological analysisBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2006MICHAEL HEADS An annotated list of indigenous Fijian seed plant genera is presented and comprises 484 genera and 1315 species in 137 families. The relative diversity of the largest families and genera in Fiji is indicated and compared with floras in New Caledonia and the Upper Watut Valley, Papua New Guinea. Differences and similarities appear to be due to biogeographical/phylogenetic factors rather than ecological differences or means of dispersal. Generic diversity for the seed plants as a whole is greatest between 0,100 m and decreases monotonically with altitude. However, in the largest family, Orchidaceae, maximum diversity occurs between 200,400 m. Fifty percent of the families are recorded from shore habitat. Twenty-seven percent of the families and 80 species occur in or around mangrove, where the most diverse families are Orchidaceae, Rubiaceae, and the legumes. Some of the mangrove-associate species are pantropical or Indo-Pacific but most are locally or regionally endemic. Fifty-six percent of the Fijian families are recorded on limestone. Twenty-nine species are restricted to limestone and 12 species usually occur on limestone. The importance of calcium in reducing the effects of salinity is emphasized and 39 species are recorded from both mangrove and limestone. A plagiotropic habit occurs in 38 species which occur on limestone or around beaches, and 20 of these are Pacific endemics. Genera restricted to higher altitudes include many present elsewhere in Melanesia but absent from Australia despite suitable habitat there, again indicating the importance of biogeographical and historical factors. Altitudinal anomalies in Fiji taxa are cited and include 7 anomalously high records from northern Viti Levu, a site of major uplift, and 22 anomalously low altitudinal records in the Lau Group, a site of subsidence. It is suggested that the Fijian flora has not been derived from immigrants from Asia, but has evolved more or less in situ. Taxa would have survived as metapopulations on the individually ephemeral volcanic islands always found at oceanic subduction zones and hot spots, and the atolls which characterize areas of subsidence. The complex geology of Fiji is determined by its position between two subduction zones of opposite polarity, the Vanuatu and Tonga Trenches, in what is currently a region of transform faulting. The large islands comprise fragments of island arcs that have amalgamated and welded together. There has been considerable uplift as well as subsidence in the islands and it is suggested that both these processes have had drastic effects on the altitudinal range of the taxa. Limestone and mangrove floras could have provided a widespread, diverse ancestral species pool from which freshwater swamp forest, lowland rainforest, dry forest, secondary forest, thickets, and montane forest have been derived during phases of uplift. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 89, 407,431. [source] Comparing the Dispersal of Large-seeded Tree Species by Frugivore Assemblages in Tropical Montane Forest in AfricaBIOTROPICA, Issue 4 2009Nicole D. Gross-Camp ABSTRACT We examined frugivore visitation and seed dispersal of five large-seeded (, 5 mm) tree species in tropical montane forest based on their occurrence in frugivorous primate diets: Ekebergia capensis, Olea capensis, Parinari excelsa, Prunus africana, and Syzygium guineense. A total of 21 frugivores in five assemblages (i.e., chimpanzees, cercopithecines, large-bodied birds, small-bodied birds, and squirrels) were observed over the study period (August 2006 and October,April 2007). We observed seed dispersal in four of five tree species studied; no dispersal was observed for P. excelsa. Frugivore assemblages did not visit tree species equally. Primates spent the most time in trees and had the largest group size. Large-bodied birds (LB) and chimpanzees dispersed the highest number of seeds per minute. LB and cercopithecines potentially dispersed the greatest number of seeds for E. capensis, and chimpanzees for S. guineense. Our analyses indicated that the mean fruiting duration of the focal tree, time in the tree, and number of species present are important predictor variables for seed dispersal by small- and large-bodied birds, and cercopithecines. The number of fruiting trees in the immediate vicinity of the focal tree further predicted seed dispersal for small-bodied birds (SB). Large-bodied birdseed dispersal also was predicted by time in tree by SB, and the number of individuals for SB and cercopithecines. Cercopithecines (CS) were further explained by the time in tree and number of species (SB & LB), and number of individuals for CS. Our study highlights the complexity of describing the relative importance of a frugivore assemblage to the dispersal of a tree species seeds. [source] Elevational Patterns of Diversity and Abundance of Eusocial Paper Wasps (Vespidae) in Costa RicaBIOTROPICA, Issue 3 2009Anjali Kumar ABSTRACT We used a standard sampling protocol to measure elevational patterns of species richness and abundance of eusocial paper wasps (Hymenoptera: Vespidae) in Costa Rica. The sample transect of six sites spanned approximately 2000 m in elevation from lowland to montane forest. Species accumulation curves and species richness estimates both document a low elevation peak in paper wasp species richness at 50 and 300 m asl, with a decline in species richness at higher elevations. Comparison of species composition among elevations revealed strong species turnover from a rich lowland fauna to a depauperate, but distinct, montane fauna. We also observed a general trend toward a greater abundance of paper wasps at higher elevations, a pattern not usually observed in eusocial insects. Army ant species that prey on paper wasps declined in abundance with elevation across the sample transect, a pattern that has been observed at other sites. We discuss the possibility that elevational changes in predation pressure affect variation in paper wasp abundance and species richness. Eusocial paper wasp species employ one of two modes of colony founding, independent and swarm founding. We found that the total abundance of individual swarm-founding wasps was higher at all elevations than the abundance of independent-founding wasps, supporting previous suggestions that Neotropical swarm founders are more successful ecologically. [source] Community Structure of Large Mammals in Tropical Montane and Lowland Forest in the Tenasserim-Dawna Mountains, ThailandBIOTROPICA, Issue 3 2008Robert Steinmetz ABSTRACT Montane evergreen forest in SE Asia is structurally and floristically different from lowland habitats. The response of large mammals to this variation is largely unexplored. We used sign transects to compare community structure of large mammals in montane (>1100 m), and lowland (<1100 m) forest types over 4 yr in western Thailand. Relative abundance of most ungulate species was significantly higher in lowland forest, except for elephant (Elephas maximus) and tapir (Tapirus indicus), which were most abundant in montane forest (based on chi-square tests of sign encounter rates). Sexual segregation was apparent for gaur (Bos gaurus): breeding herds were concentrated in the lowlands, whereas single males were most abundant in montane forest. Large cat abundance was similar in both elevation zones. Tapir, single gaur, and bears (Ursus spp.) characterized the montane mammal community, whereas most other ungulate species and social groups were indicative of lowland forest (based on discriminant function analysis). Results pertain only to the dry season; seasonal movements could alter the patterns we observed. Differences in community structure between elevation zones are hypothesized to result from differences in habitat structure, resource availability, and human impacts. Lowland forests provide bamboo, grass, and mineral licks, probably accounting for higher ungulate densities despite higher levels of hunting. These resources are scarce in montane forest. However, montane forest functions as a refuge for at least three globally threatened large mammal species, because commercial hunting is concentrated in the more accessible lowlands. [source] Retention of Inorganic Nitrogen by Epiphytic Bryophytes in a Tropical Montane Forest,BIOTROPICA, Issue 3 2005Kenneth 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] Comparison and Origin of Forest and Grassland Ant Assemblages in the High Plateau of Madagascar (Hymenoptera: Formicidae),BIOTROPICA, Issue 1 2002Brian L. Fisher ABSTRACT We assessed species richness and composition of ant assemblages in adjacent montane forest and secondary (anthropogenic) grassland habitats in the central plateau of Madagascar. We used five quantitative methods (leaf litter sifting, two types of pitfall traps, beating low vegetation, and soil digging) and compared methods within and across habitats. Sample,based and occurrence,based accumulation curves demonstrated that die efficiency of ant inventory methods is habitat specific. Litter sifting, however, was the single most efficient method in both habitats. Overall, our analyses of the relative efficiency of methods recommend the use of sifting and beating in the montane forest site, and sifting alone in the grassland site. In four of five methods, more species were collected in the grassland site (31 spp.) than in the forest site (26 spp.). Occurrence,based accumulation curves based on all methods demonstrated that species richness was similar in the two habitats, reaching a maximum difference of approximately one species. Only five species were shared between the grassland and forest sites. The presence of a high number of ant species restricted to the grassland site (18 spp.) is the first record of high endemism in this habitat in Madagascar and may have strong implications for the reconstruction of the natural vegetation types at the time humans arrived. Their presence suggests that a comparable open habitat, such as montane woodland, shrubland, or thicket, was present on Madagascar long before humans developed the secondary grasslands less than 2000 years ago. These results are contrary to the "classical hypothesis" that the central plateau was a continuous region of closed forest. These results support the hypothesis that the montane regions, including the central plateau, once contained areas of habitat with an open structure and that the endemic ants now found in the secondary grasslands were originally native to such a habitat. RéSUMé La richesse en espéces et la composition des fourmis ont été inventoriées dans la for,t montagneuse du plateau central de Madagascar et dans la prairie secondaire adjacente. Cinq méthodes quantitatives ont été utilisées (tamisage des litières, deux types de trous-pièges, battage des végétations basses et lavage de terre). Nous avons comparé I'efficacité de ces méthodes dans chacun et entre les deux habitats. Les courbes d'accumulation d'espèces basées sur I'échantillon et sur I'occurrence ont montré que I'efficacité des méthodes d'inventaire de fourmis est habitat-dépendant. Cependant, le tamisage des litières se montrait la méthode la plus efficace dans les deux habitats. Nos analyses sur I'efficacité relative des méthodes recommandent I'utilisation combinée du tamisage des litières et du battage de végétation dans la for,t montagneuse, et I'utilisation seule du tamisage des litières dans la prairie secondaire. Dans quatre des cinq méthodes, plus d'espèces ont été collectées dans la prairie (31 spp.) que dans la for,t (26 spp.). Les courbes d'accumulation d'occurrence basées sur routes les méthodes ont démontré que la richesse en espèces de ces deux habitats est similaire, atteignant seulement une difference maximale d'approximativement une espèce. Pourtant, seulement cinq espèces parta-geaient les deux habitats. La présence de plusieurs espèces de fourmis uniquement trouvées dans la prairie (18 spp.) est la première observation d'une forte endémicité de cet habitat et peut avoir une importante implication pour la restauration des types de végétation naturelle initiale de I'ile. Leur présence suggère que des habitats ouverts similaires tels que les formations arbustives de montagnes et les fourrés, étaient présentsà Madagascar longtemps avant la transformation de ces habitats en prairie secondaire par les humains. Ces résultats contredisent I'hypothèse classique qui avance que le plateau central a é té uniquement composé d'une région de for,t dense. Ainsi, ces résultats supportent I'hypothese que la région montagneuse contenant le plateau central, renfermait des habitats àstructure ouverte et que les fourmis endémiques actuellement trouvées dans la prairie secondaire sont, a I'origine natives de ces habitats. [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] 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] Applying climatically associated species pools to the modelling of compositional change in tropical montane forestsGLOBAL ECOLOGY, Issue 2 2008Duncan J. Golicher ABSTRACT Aim, Predictive species distribution modelling is a useful tool for extracting the maximum amount of information from biological collections and floristic inventories. However, in many tropical regions records are only available from a small number of sites. This can limit the application of predictive modelling, particularly in the case of rare and endangered species. We aim to address this problem by developing a methodology for defining and mapping species pools associated with climatic variables in order to investigate potential species turnover and regional species loss under climate change scenarios combined with anthropogenic disturbance. Location, The study covered an area of 6800 km2 in the highlands of Chiapas, southern Mexico. Methods, We derived climatically associated species pools from floristic inventory data using multivariate analysis combined with spatially explicit discriminant analysis. We then produced predictive maps of the distribution of tree species pools using data derived from 451 inventory plots. After validating the predictive power of potential distributions against an independent historical data set consisting of 3105 botanical collections, we investigated potential changes in the distribution of tree species resulting from forest disturbance and climate change. Results, Two species pools, associated with moist and cool climatic conditions, were identified as being particularly threatened by both climate change and ongoing anthropogenic disturbance. A change in climate consistent with low-emission scenarios of general circulation models was shown to be sufficient to cause major changes in equilibrium forest composition within 50 years. The same species pools were also found to be suffering the fastest current rates of deforestation and internal forest disturbance. Disturbance and deforestation, in combination with climate change, threaten the regional distributions of five tree species listed as endangered by the IUCN. These include the endemic species Magnolia sharpii Miranda and Wimmeria montana Lundell. Eleven vulnerable species and 34 species requiring late successional conditions for their regeneration could also be threatened. Main conclusions, Climatically associated species pools can be derived from floristic inventory data available for tropical regions using methods based on multivariate analysis even when data limitations prevent effective application of individual species modelling. Potential consequences of climate change and anthropogenic disturbance on the species diversity of montane tropical forests in our study region are clearly demonstrated by the method. [source] Influences of climate on fire regimes in montane forests of north-western MexicoJOURNAL OF BIOGEOGRAPHY, Issue 8 2008Carl N. Skinner Abstract Aim, To identify the influence of interannual and interdecadal climate variation on the occurrence and extent of fires in montane conifer forests of north-western Mexico. Location, This study was conducted in Jeffrey pine (Pinus jeffreyi Grev. & Balf.)-dominated mixed-conifer forests in the central and northern plateau of the Sierra San Pedro Mártir, Baja California, Mexico. Methods, Fire occurrence was reconstructed for 12 dispersed sites for a 290-year period (1700,1990) from cross-dated fire-scarred samples extracted from live trees, snags and logs. Superposed epoch analysis was used to examine the relationships of tree-ring reconstructions of drought, the El Niño/Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) with fire occurrence and extent. Results, Years with no recorded fire scars were wetter than average. In contrast, years of widespread fires were dry and associated with phase changes of the PDO, usually from positive (warm) to negative (cold). The influence of the PDO was most evident during the La Niña phase of the ENSO. Widespread fires were also associated with warm/wet conditions 5 years before the fire. We hypothesize that the 5-year lag between warm/wet conditions and widespread fires may be associated with the time necessary to build up sufficient quantity and continuity of needle litter to support widespread fires. Two periods of unusually high fire activity (1770,1800 and 1920,1950) were each followed by several decades of unusually low fire activity. The switch in each case was associated with strong phase changes in both PDO and ENSO. Main conclusions, Climate strongly influences fire regimes in the mountains of north-western Mexico. Wet/warm years are associated with little fire activity. However, these years may contribute to subsequent fire years by encouraging the production of sufficient needle litter to support more widespread fires that occur in dry/cool years. [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] | |||||||||||||||||||||||||