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Integrating regional and continental scale comparisons of tree composition in Amazonian terra firme forests  [PDF]
E. N. Honorio Coronado,T. R. Baker,O. L. Phillips,N. C. A. Pitman
Biogeosciences Discussions , 2009,
Abstract: We contrast regional and continental-scale comparisons of the floristic composition of terra firme forest in South Amazonia, using 55 plots across Amazonia and a subset of 30 plots from northern Peru and Ecuador. Firstly, we examine the floristic patterns using both genus- or species-level data and find that the species-level analysis more clearly distinguishes different plot clusters. Secondly, we compare the patterns and causes of floristic differences at regional and continental scales. At a continental scale, ordination analysis shows that species of Lecythidaceae and Sapotaceae are gradually replaced by species of Arecaceae and Myristicaceae from eastern to western Amazonia. These floristic gradients are correlated with gradients in soil fertility and to dry season length, similar to previous studies. At a regional scale, similar patterns are found within north-western Amazonia, where differences in soil fertility distinguish plots where species of Lecythidaceae, characteristic of poor soils, are gradually replaced by species of Myristicaceae on richer soils. The main coordinate of this regional-scale ordination correlates mainly with concentrations of available calcium and magnesium. Thirdly, we ask at a regional scale within north-western Amazonia, whether soil fertility or other distance dependent processes are more important for determining variation in floristic composition. A Mantel test indicates that both soils and geographical distance have a similar and significant role in determining floristic similarity across this region. Overall, these results suggest that regional-scale variation in floristic composition can rival continental scale differences within Amazonian terra firme forests, and that variation in floristic composition at both scales is dependent on a range of processes that include both habitat specialisation related to edaphic conditions and other distance-dependent processes. To fully account for regional scale variation in continental studies of floristic composition, future floristic studies should focus on forest types poorly represented at regional scales in current datasets such as terra firme forests with high soil fertility from north-western Amazonia.
Tree communities of white-sand and terra-firme forests of the upper Rio Negro
Stropp, Juliana;Sleen, Peter Van der;Assun??o, Paulo Apóstolo;Silva, Adeilson Lopes da;Steege, Hans Ter;
Acta Amazonica , 2011, DOI: 10.1590/S0044-59672011000400010
Abstract: the high tree diversity and vast extent of amazonian forests challenge our understanding of how tree species abundance and composition varies across this region. information about these parameters, usually obtained from tree inventories plots, is essential for revealing patterns of tree diversity. numerous tree inventories plots have been established in amazonia, yet, tree species composition and diversity of white-sand and terra-firme forests of the upper rio negro still remain poorly understood. here, we present data from eight new one-hectare tree inventories plots established in the upper rio negro; four of which were located in white-sand forests and four in terra-firme forests. overall, we registered 4703 trees > 10 cm of diameter at breast height. these trees belong to 49 families, 215 genera, and 603 species. we found that tree communities of terra-firme and white-sand forests in the upper rio negro significantly differ from each other in their species composition. tree communities of white-sand forests show a higher floristic similarity and lower diversity than those of terra-firme forests. we argue that mechanisms driving differences between tree communities of white-sand and terra-firme forests are related to habitat size, which ultimately influences large-scale and long-term evolutionary processes.
Structure and composition of the ground-herb community in a terra-firme Central Amazonian forest
Costa, Flávia Regina Capellotto;
Acta Amazonica , 2004, DOI: 10.1590/S0044-59672004000100007
Abstract: the herb community of tropical forests is very little known, with few studies addressing its structure quantitatively. even with this scarce body of information, it is clear that the ground herbs are a rich group, comprising 14 to 40% of the species found in total species counts in tropical forests. the present study had the objective of increasing the knowledge about the structure and composition of the ground-herb community and to compare the sites for which there are similar studies. the study was conducted in a tropical non-inundated and evergreen forest 90 km north of manaus, am. ground herbs were surveyed in 22 transects of 40 m2, distributed in five plots of 4 ha. the inventoried community was composed of 35 species, distributed in 24 genera and 18 families. angiosperms were represented by 8 families and pteridophytes by 10 families. marantaceae (12 sp) and cyperaceae (4 sp) were the richest families. marantaceae and poaceae were the families with greatest abundance and cover. marantaceae, poaceae, heliconiaceae and pteridophytes summed 96% of total herb cover, and therefore were responsible for almost all the cover of the community. the 10 most important species had 83.7% of the individuals. in general, the most abundant species were also the most frequent. richness per transect varied from 7 to 19 species, and abundance varied from 30 to 114 individuals. the community structure was quite similar to 3 other sites in south america and one site in asia.
Necromass in forests of Madre de Dios, Peru: a comparison between terra firme and lowland forests Necromasa de los bosques de Madre de Dios, Perú; una comparación entre bosques de tierra firme y de bajíos  [cached]
Alejandro Araujo-Murakami,Alexander G. Parada,Jeremy J. Terán,Tim R. Baker
Revista Peruana de Biología , 2011,
Abstract: Stocks of dead wood or necromass represent an important portion of biomass and nutrients in tropical forests. The objectives of this study were: 1) to evaluate and compare the necromass of “terra firme” and lowlands forests, (2) to study the relationship between necromass, above-ground biomass and wood density, and (3) to estimate the necromass of the department of Madre de Dios, Peru. Stocks of necromass and above-ground biomass were estimated at three different locations using permanent plots and line intercept transects. The average volume of necromass for the three sites was 72.9 m3 ha-1 with an average weight varying between 24.8 and 30.7 Mg ha-1, depending on the estimations of dead wood density used for the calculations. Terra firme forests had significantly higher stocks of necromass than lowland forests. The amount of necromass was 11% of the total above-ground biomass in Madre de Dios forests. The total stock of carbon stored in dead wood for the entire department of Madre de Dios was estimated to be approximately 100 mega tonnes of carbon. This is ten times more than the annual fossil fuel emissions of Peru between 2000 and 2008. The substantial stocks of necromass emphasize the importance of these types of field studies, considering that this component of tropical forest carbon cannot be detected using other methods such as satellite remote sensing. La cantidad de madera muerta o necromasa representa una importante porción de la biomasa y de los nutrientes en los bosques tropicales. Los objetivos de este estudio son: 1) hacer una evaluación y comparación entre la necromasa de los bosques de altura o tierra firme y los bosques inundables o bajíos, (2) estudiar las relaciones entre la necromasa, la biomasa aérea y la densidad de madera del bosque, y (3) proporcionar una primera estimación de la necromasa para todo el departamento de Madre de Dios. La necromasa gruesa y la masa aérea vegetativa fueron estudiados en tres diferentes lugares utilizando parcelas permanentes y líneas de intersección. El promedio del volumen de madera muerta gruesa fue de 72,9 m3 ha-1, con un peso entre 24,8 y 30,7 Mg ha-1 dependiendo de la densidad de madera muerta usada en los cálculos. Los bosques de tierra firme contienen significativamente más madera muerta que los bosques inundables. La necromasa constituye 11% de la masa aérea vegetativa almacenada en los bosques de Madre de Dios. Finalmente, se estima que el departamento de Madre de Dios contiene alrededor de 100 mega toneladas de carbono en su madera muerta. Este valor es bastante alto, siendo diez veces más
Floristic, edaphic and structural characteristics of flooded and unflooded forests in the lower Rio Purús region of central Amazonia, Brazil
Haugaasen, Torbj?rn;Peres, Carlos Augusto;
Acta Amazonica , 2006, DOI: 10.1590/S0044-59672006000100005
Abstract: despite a natural history interest in the early 1900s, relatively little ecological research has been carried out in the rio purús basin of central amazonia, brazil. here we describe a new study area in the region of lago uaua?ú with an emphasis on the climate, forest structure and composition, and soil characteristics between adjacent unflooded (terra firme) and seasonally inundated forests; situated within both the white-water (várzea) and black-water (igapó) drainage systems that dominate the landscape. the climate was found to be typical of that of the central amazon. várzea forest soils had high concentrations of nutrients, while terra firme and igapó soils were comparatively nutrient-poor. terra firme forests were the most floristically diverse forest type, whereas várzea was intermediate, and igapó the most species-poor. the lecythidaceae was the most important family in terra firme while the euphorbiaceae was the most important in both várzea and igapó. there were significant differences between forest types in terms of number of saplings, canopy cover and understorey density. in contrasting our results with other published information, we conclude that the lago uaua?ú region consists of a typical central amazonian forest macro-mosaic, but is a unique area with high conservation value due to the intimate juxtaposition of terra firme, várzea and igapó forests.
Floristic, edaphic and structural characteristics of flooded and unflooded forests in the lower Rio Purús region of central Amazonia, Brazil
Haugaasen Torbj?rn,Peres Carlos Augusto
Acta Amazonica , 2006,
Abstract: Despite a natural history interest in the early 1900s, relatively little ecological research has been carried out in the Rio Purús basin of central Amazonia, Brazil. Here we describe a new study area in the region of Lago Uaua ú with an emphasis on the climate, forest structure and composition, and soil characteristics between adjacent unflooded (terra firme) and seasonally inundated forests; situated within both the white-water (várzea) and black-water (igapó) drainage systems that dominate the landscape. The climate was found to be typical of that of the central Amazon. Várzea forest soils had high concentrations of nutrients, while terra firme and igapó soils were comparatively nutrient-poor. Terra firme forests were the most floristically diverse forest type, whereas várzea was intermediate, and igapó the most species-poor. The Lecythidaceae was the most important family in terra firme while the Euphorbiaceae was the most important in both várzea and igapó. There were significant differences between forest types in terms of number of saplings, canopy cover and understorey density. In contrasting our results with other published information, we conclude that the Lago Uaua ú region consists of a typical central Amazonian forest macro-mosaic, but is a unique area with high conservation value due to the intimate juxtaposition of terra firme, várzea and igapó forests.
Vertical stratification of bat assemblages in flooded and unflooded Amazonian forests  [cached]
Maria Jo?o Ramos PEREIRA, Jo?o Tiago MARQUES, Jorge M. PALMEIRIM
Current Zoology , 2010,
Abstract: Tropical rainforests usually have multiple strata that results in a vertical stratification of ecological opportunities for animals. We investigated if this stratification influences the way bats use the vertical space in flooded and unflooded forests of the Central Amazon. Using mist-nets set in the canopy (17 to 35 m high) and in the understorey (0 to 3 m high) we sampled four sites in upland unflooded forests (terra firme), three in forests seasonally flooded by nutrient-rich water (várzea), and three in forests seasonally flooded by nutrient-poor water (igapó). Using rarefaction curves we found that species richness in the understorey and canopy were very similar. An ordination analysis clearly separated the bat assemblages of the canopy from those of the understorey in both flooded and unflooded habitats. Gleaning carnivores were clearly associated with the understorey, whereas frugivores were abundant in both strata. Of the frugivores, Carollinae and some Stenodermatinae were understorey specialists, but several Stenodermatinae mostly used the canopy. The first group mainly includes species that, in general, feed on fruits of understorey shrubs, whereas the second group feed on figs and other canopy fruits. We conclude that vertical stratification in bat communities occurs even within forests with lower canopy heights, such as Amazonian seasonally flooded forests, and that the vertical distribution of bat species is closely related to their diet and foraging behaviour [Current Zoology 56 (4): 469–478, 2010].
Compara??o entre florestas de várzea e de terra firme do Estado do Pará
Gama, Jo?o Ricardo Vasconcellos;Souza, Agostinho Lopes de;Martins, Sebasti?o Venancio;Souza, Deoclides Ricardo de;
Revista árvore , 2005, DOI: 10.1590/S0100-67622005000400013
Abstract: floristic groups among arboreous communities were analyzed in different regions of pará state, using 34 different forest inventory (24 on "terra firme" and 10 on "várzea" forests) data basis. the jaccard index was used to calculate the matrix of floristic similarity, which was turned into a euclidean matrix of distance, and the ward method to define groups. through the results it was possible to conclude that the floristic composition of varzea and terra firme forests are quite different. few species occur in both ecosystems; terra firme forest shows a higher tree species richness than varzea forest. there was a cluster tendency of terra firme forests, more related to the anthropic situation and geographic proximity than varzea forests; in general, the forests formed clusters according to a decreasing order of importance, such as: soil hydric saturation, anthropic situation and geographic proximity.
Influence of drainage status on soil and water chemistry, litter decomposition and soil respiration in central Amazonian forests on sandy soils  [cached]
Fabrício Berton Zanchi,Maarten Johannes Waterloo,Albertus Johannes Dolman,Margriet Groenendijk
Ambiente e água : An Interdisciplinary Journal of Applied Science , 2011,
Abstract: Central Amazonian rainforest landscape supports a mosaic of tall terra firme rainforest and ecotone campinarana, riparian and campina forests, reflecting topography-induced variations in soil, nutrient and drainage conditions. Spatial and temporal variations in litter decomposition, soil and groundwater chemistry and soil CO2 respiration were studied in forests on sandy soils, whereas drought sensitivity of poorly-drained valley soils was investigated in an artificial drainage experiment. Slightly changes in litter decomposition or water chemistry were observed as a consequence of artificial drainage. Riparian plots did experience higher litter decomposition rates than campina forest. In response to a permanent lowering of the groundwater level from 0.1 m to 0.3 m depth in the drainage plot, topsoil carbon and nitrogen contents decreased substantially. Soil CO2 respiration decreased from 3.7±0.6 μmol m-2 s-1 before drainage to 2.5±0.2 and 0.8±0.1 μmol m-2 s-1 eight and 11 months after drainage, respectively. Soil respiration in the control plot remained constant at 3.7±0.6 μmol m-2 s-1. The above suggests that more frequent droughts may affect topsoil carbon and nitrogen content and soil respiration rates in the riparian ecosystem, and may induce a transition to less diverse campinarana or short-statured campina forest that covers areas with strongly-leached sandy soil.
Sampling effort and fish species richness in small terra firme forest streams of central Amazonia, Brazil
Anjos, Maeda Batista dos;Zuanon, Jansen;
Neotropical Ichthyology , 2007, DOI: 10.1590/S1679-62252007000100006
Abstract: small streams are important components of the landscape in terra firme forests in central amazonia and harbor a large number of fish species. nevertheless, the lack of a common sampling protocol in studies of this ichthyofauna hinders comparisons among available results. this study evaluates how the length of stream reach sampled affects estimates of local fish species density in 1st, 2nd, and 3rd order streams, and proposes a mean minimum sampling length that best approximates the absolute number of species in a given stream segment. we sampled three streams in the biological dynamics of forest fragments project's study sites, between may and august 2004. at each stream, one 1st order, one 2nd order, and one 3rd order segment was sampled. we sampled five 20-m reaches in each stream segment. three to four people collected along each reach for 45 to 60 minutes. we used jaccard's coefficient to estimate the similarity of species composition among stream reaches and segments. estimates of species richness were obtained with jackknife 1 and bootstrap algorithms and species accumulation curves. we used simple linear regressions to look for relationships between species density and fish abundance and between species density and the volume of 100-m stream segments. species density in 1st order stream reaches was slightly higher than in 2nd and 3rd order stream reaches, whereas fish abundance was apparently higher in 3rd order reaches. similarity in fish species composition between 20-m reaches was low for all studied streams. species density values in pooled 100-m stream segments represented 71.4% to 94.1% of the estimated values for these streams. species density showed a direct relationship both with volume of the sampled stream segment and fish abundance. it seems plausible that larger streams contain a higher number of microhabitat types, which allow for the presence of more fish species per stream length. based on the values of asymptotes and equations for species acc
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