Diversity of palm uses in the western Amazon

We used palm knowledge to understand the interaction between people and the rainforests and the factors that influence this dynamic process. We interviewed 278 informants in 12 villages in the Pastaza and Madidi areas of the western Amazon basin. Together they used 38 different palm species for 38 different uses in six use-categories (food, construction, utensils, ritual, medicine, commercial). Euterpe precatoria, Iriartea deltoidea, and Oenocarpus bataua were best known and were mentioned as useful by 76–72% of the informants in the 12 villages. There was a great variation in number of uses and in how widespread the uses were and five of the 38 useful palms were mentioned by only one informant. Among the socioeconomic factors analyzed, the residence village influenced the informants’ knowledge of palms and their uses more than any other factor. Length of education, prosperity and for how long the informant had lived in the village were also positively correlated to how many palms and palm uses were known. Gender differences in informants’ knowledge of palm uses were not observed in our data. We suggest, that the high importance of forest products to the livelihood of the villagers, the great variation in the knowledge they possess, and the fact that the differences between villages is so great, are important elements to consider when developing management plans for the sustainable use of the rainforest resources in the western Amazon.     

Flowering phenology of a palm community in a central Amazon forest

The flowering phenology of 27 taxa of palms in a lowland moist forest in the central Amazon was recorded over a 40 month period. Phenological data were transformed into measures, of synchrony, regularity, and duration. Flowering was observed at all times of year and there was no correlation with rainfall either for the current month or for any monthly lag interval. The 27 taxa were divided into three pollination groups—weevil, bee/fly, or beetle—based on their behavior at anthesis. Phenology was significantly correlated with pollination groups. Weevilpollinated palms had higher synchrony and shorter duration of flowering than other groups. Bee/fly-pollinated palms had lower synchrony and longer duration of flowering. The beetle-pollinated palms were intermediate between the two other groups. Seasonal regularity of flowering was similar in all three groups. We suggest that, at least inBactris, taxa exhibit staggered flowering.     

Long-term potential for tropical-forest degradation due to deforestation and fires in the Brazilian Amazon

Biome models of the global climate-vegetation relationships indicate that most of the Brazilian Amazon has potential for being covered by tropical forests. From current land-use processes observed in the region, however, substantial deforestation and fire activity have been verified in large portions of the region, particularly along the Arc of Deforestation. In a first attempt to evaluate the long-term potential for tropical-forest degradation due to deforestation and fires in the Brazilian Amazon, we analysed large-scale data on fire activity and climate factors that drive the distribution of tropical forests in the region. The initial analyses and results from this study lead to important details on the relations between these quantities and have important implications for building future parameterizations of the vulnerability of tropical forests in the region.     

Variations in Amazon forest productivity correlated with foliar nutrients and modelled rates of photosynthetic carbon supply

The rate of above-ground woody biomass production, W(P), in some western Amazon forests exceeds those in the east by a factor of 2 or more. Underlying causes may include climate, soil nutrient limitations and species composition. In this modelling paper, we explore the implications of allowing key nutrients such as N and P to constrain the photosynthesis of Amazon forests, and also we examine the relationship between modelled rates of photosynthesis and the observed gradients in W(P). We use a model with current understanding of the underpinning biochemical processes as affected by nutrient availability to assess: (i) the degree to which observed spatial variations in foliar [N] and [P] across Amazonia affect stand-level photosynthesis; and (ii) how these variations in forest photosynthetic carbon acquisition relate to the observed geographical patterns of stem growth across the Amazon Basin. We find nutrient availability to exert a strong effect on photosynthetic carbon gain across the Basin and to be a likely important contributor to the observed gradient in W(P). Phosphorus emerges as more important than nitrogen in accounting for the observed variations in productivity. Implications of these findings are discussed in the context of future tropical forests under a changing climate.     

Land use change in the Amazon estuary: Patterns of caboclo settlement and landscape management

Landsat TM scenes for 1985 and 1991 are used to produce a georeferenced map of land cover and land use for an area of the Amazon estuary inhabited by three populations of caboclos with distinct patterns of land use. This information is combined in a geographic information system with ethnographic and survey research carried out over the past 5 years to develop representative spectral signatures which permit measurement and differentiation of land uses and the detection of change even between small areas of managed floodplain forest and unmanaged forest, and between three distinct age/growth classes of secondary succession following deforestation. Implementation of these procedures permit the scaling up or down of research at different resolutions. Three distinct patterns of land use are examined with differential impact on the environment. Mechanized agriculture at one site has eliminated virtually all the mature upland forest and is now dominated by secondary successional vegetation. The more traditional system of diversified land use at the next site shows a subtle cycling of flooded forest to managed palm forest through time in response to the price of palm fruit and cycling in the use of fallow land. A third site, based on palm fruit extractivism, shows minimal changes in land cover due to persistent specialization on management of flooded forest extraction. There is little evidence that the community with the greatest impact on forest cover is any better off economically than the two communities which have minimal impact on the landscape. This study suggests how a balance between use and conservation in Amazonia may be achieved in floodplain and estuarine areas, and the effectiveness of monitoring these types of land cover from satellite platforms.     

The stable carbon and nitrogen isotopic composition of vegetation in tropical forests of the Amazon Basin, Brazil

Here we present the within-site, seasonal, and interannual variations of the carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope ratios of leaves, wood, bark and litter from four sites in the Amazon region, Brazil. Samples were collected in Manaus (3° 06′07′′ S; 60°01′30′′ W), Ji-Paraná (10°53′07′′ S; 61°57′06′′ W), and Santarém (2°26′35′′ S; 54°42′30′′ W) with mean annual precipitation of 2207, 2040 and 1909 mm respectively. The overall average for all leaf samples was for δ¹³C and for δ¹⁵N (n=756). The leaf δ values at these sites were often but not always statistically distinct from each other. The δ¹³C values varied from to . Pronounced differences in δ¹³C values occurred with height associated with differences in forest structure. The δ¹³C of leaf dry matter showed seasonal variations associated with the length of the dry season, despite the fact that total annual precipitation was similar among the studied sites. Leaf δ¹⁵N values ranged from to a maximum value of , and the Santarém sites showed more enriched values than Manaus and Ji-Paraná sites. No seasonal variation was detected in the δ¹⁵N of leaves, but significant differences were observed among sites and with changes in canopy height. The isotope ratio data are consistent with our current understanding of the roles of light, water availability, and recycling of soil-respired CO₂ influences on δ¹³C and consistent with our understanding that an open nitrogen cycle can lead to high δ¹⁵N values despite a significant number of legumes in the vegetation.     

Transport of larval fish in the Amazon

In the Amazon near Manaus, larvae of Characiformes, Clupeiformes, Tetraodontiformes, Pleuronectiformes, Gymnotiformes, Belonidae and Sciaenidae were sampled in the river during most of the year, except in June and July, when the water level was at its maximum. Characiformes, Tetraodontiformes and Siluriformes were found in the ichthyoplankton mostly during the rising waters, but Clupeiformes and Sciaenidae drifted in the river almost all year around. Egg abundance was extremely low, suggesting that they do not drift or have a very short residence time. Two types of larval drift seemed to occur: a rising water drift and a lowering water drift. Characiformes, Tetraodontiformes and some Clupeiformes drifted mostly during the rising waters and were more abundant near the banks. Their strategy seemed to be a passive dispersion towards the floodplain with the flood pulse. The high densities near the banks optimized their chances of reaching a floodplain inlet. The groups that drifted during the lowering waters showed an alternative strategy. They were flushed from the floodplain lakes and may have stayed in the main river channel for a few months before returning to the floodplain. Predation in the lakes during the period when water level decline was probably the force behind this drift.     

Valuing the rain forest: Economic strategies by small-scale forest extractivists in the Amazon estuary

The current interest in non-timber forest products as an economic option for the Brazilian Amazon represents a radical departure from the policies that have guided development in the region during recent decades. Despite this interest, little is currently known about the forms of resource management or economic strategies practiced by populations dependent on such resources. In this study, we measured the annual income and expenditures of ten households on Combu Island, located in the Amazon estuary near the major port city of Belém; in addition, we documented local uses and management of natural resources on the island Average annual income per household was found to be over U.S. $4000, derived primarily from the harvest and sale of non-timber forest products. The results of this study show that the combination of proximity to a major market and appropriate resource management can lead to high and apparently sustainable economic returns.Formerly Senior Researcher at the Museu Paraense Emílio GoeldiFormerly Student Fellow at the Museu Paraense Emílio Goeldi     

Production of cellulolytic enzymes from fungi and use in the saccharification of palm cake and palm fibre

Aspergillus niger ATCC 6275 possesses the highest carboxymethyl-cellulase, xylanase and -glucosidase activities under liquid and solid cultivations compared withMyceliophthora thermophila IFO 31843 and an isolate, F11. Palm cake proved to be a better substrate for enzyme production and saccharification than palm fibre. Saccharification of these two substrates, using crude enzyme solutions from three fungi and commercial enzymes, was investigated.     

Spatial and temporal dynamics of forest canopy gaps following selective logging in the eastern Amazon

Selective logging is a dominant form of land use in the Amazon basin and throughout the humid tropics, yet little is known about the spatial variability of forest canopy gap formation and closure following timber harvests. We established chronosequences of large‐area (14–158 ha) selective logging sites spanning a 3.5‐year period of forest regeneration and two distinct harvest methods: conventional logging (CL) and reduced‐impact logging (RIL). Our goals were to: (1) determine the spatial characteristics of canopy gap fraction immediately following selective logging in the eastern Amazon; (2) determine the degree and rate of canopy closure in early years following harvest among the major landscape features associated with logging – tree falls, roads, skid trails and log decks; and (3) quantify spatial and temporal differences in canopy opening and closure in high‐ and low‐damage harvests (CL vs. RIL). Across a wide range of harvest intensities (2.6–6.4 felled trees ha^?1), the majority of ground damage occurred as skid trails (4–12%), whereas log decks and roads were only a small contributor to the total ground damage (<2%). Despite similar timber harvest intensities, CL resulted in more ground damage than RIL. Neither the number of log decks nor their individual or total area was correlated with the number of trees removed or intensity of tree harvesting (trees ha^?1). The area of skids was well correlated with the ground area damaged (m²) per tree felled. In recently logged forest (0.5 years postharvest), gap fractions were highest in log decks (mean RIL=0.83, CL=0.99) and lowest in tree‐fall areas (RIL: 0.26, CL: 0.41). However, the small surface area of log decks made their contribution to the total area‐integrated forest gap fraction minor. In contrast, tree falls accounted for more than two‐thirds of the area disturbed, but the canopy gaps associated with felled trees were much smaller than for log decks, roads and skids. Canopy openings decreased in size with distance from each felled tree crown. At 0.5 years postharvest, the area initially affected by the felling of each tree was approximately 100 m in radius for CL and 50 m for RIL. Initial decreases in gap fraction during the first 1.5 years of regrowth diminished in subsequent years. Throughout the 3.5‐year period of forest recovery, tree‐fall gap fractions remained higher in CL than in RIL treatments, but canopy gap closure rates were higher in CL than in RIL areas. During the observed recovery period, the canopy gap area affected by harvesting decreased in radius around each felled tree from 100 to 40 m in CL, and from 50 to 10 m in RIL. The results suggest that the full spatial and temporal dynamics of canopy gap fraction must be understood and monitored to predict the effects of selective logging on regional energy balance and climate regimes, biogeochemical processes including carbon cycling, and plant and faunal population dynamics. This paper also shows that remote sensing of log decks alone will not provide an accurate assessment of total forest area impacted by selective logging, nor will it be closely correlated to damage levels and canopy gap closure rates.     

The effect of land-use on the local distribution of palm species in an Andean rain forest fragment in northwestern Ecuador

The northern Andes is extremely rich in plant species, but this diversity is threatened by extensive deforestation. This study reports on how five palm species respond to human disturbance in an area of montane forest in Ecuador. The abundance of each species was determined in 250 40 × 30m plots, established in disturbed and undisturbed forest within an area of 3 × 3km and altitudes spanning 1248–1938m. Aiphanes erinacea (H. Karst.) H. Wendl. and to a lesser degree Geonoma undata Klotzsch were negatively affected by even moderate human disturbance, while Chamaedorea linearis (Ruiz & Pav.) Mart. and C. pinnatifrons (Jacq.) Oerst. benefitted from such disturbance and Prestoea acuminata (Willd.) H.E. Moore was unaffected given time enough to replenish its population after disturbance. At the scale of the plots, species richness was maximized in undisturbed forest. Aiphanes erinacea is endemic to northern Ecuador and southern Colombia and must be considered threatened by the extensive deforestation here. If the behaviour of these palms is representative of Andean rain forest plans in general, the negative effect of moderate anthropogenic disturbance on plant biodiversity at scales of 1km2 might be negligible. Thus, biologically sustainable logging could be possible.     

Modeling changes in soil organic matter in Amazon forest to pasture conversion with the Century model

Land use and land cover changes in the Brazilian Amazon region have major implications for regional and even global carbon cycling. We analyzed the effects of the predominant land use change, conversion of tropical forest to pasture, on total soil C and N, using the Century ecosystem model and data collected from the Nova Vida ranch, Western Brazilian Amazon. We estimated equilibrium organic matter levels, plant productivity and residue carbon inputs under native forest conditions, then simulated deforestation following the slash and burn procedure. Soil organic matter dynamics were simulated for pastures established in 1989, 1987, 1983, 1979, 1972, 1951, and 1911. Using input data from the Nova Vida ranch, the Century model predicted that forest clearance and conversion to pasture would cause an initial decline in soil C and N stocks, followed by a slow rise to levels exceeding those under native forest. Simulated soil total C and N levels (2500 g C m^?2 and 245 g N m^?2 in the 0–20 cm layer) prior to conversion to pasture were close to those measured in the native forest. Simulated above‐ and below‐ground biomass for the forest and pasture were comparable with literature values from this region. The model predicted the long‐term changes in soil C and N under pasture inferred from the pasture chronosequence, but there was considerable variation in soil C stocks for pastures <20 years in age. Differences in soil texture between pastures were relatively small and could not account for much of the variability between different pastures of similar ages, in either the measured or simulated data. It is likely that much of the variability in C stocks between pastures of similar ages is related to initial C stocks immediately following deforestation and that this was the largest source of variability in the chronosequence. Internal C cycling processes in Century were evaluated using measurements of microbial biomass and soil δ¹³C. The relative magnitude and long‐term trend in microbial biomass simulated by the model were consistent with measurements. The close fit of simulated to measured values of δ¹³C over time suggests that the relative loss of forest‐derived C and its replacement by pasture‐derived C was accurately predicted by the model. After 80 years, almost 90% of the organic matter in the top 20 cm was pasture derived. While our analysis represents a single ‘case study’ of pasture conversion, our results suggest that modeling studies in these pasture systems can help to evaluate the magnitude of impacts on C and N cycling, and determine the effect of management strategies on pasture sustainability.     

Coarse woody debris in undisturbed and logged forests in the eastern Brazilian Amazon

Coarse woody debris (CWD) is an important component of the carbon cycle in tropical forests. We measured the volume and density of fallen CWD at two sites, Cauaxi and Tapajós in the Eastern Amazon. At both sites we studied undisturbed forests (UFs) and logged forests 1 year after harvest. Conventional logging (CL) and reduced impact logging (RIL) were used for management on areas where the geometric volumes of logs harvested was about 25–30 m³ ha^?1. Density for five classes of fallen CWD for large material (>10 cm diameter) ranged from 0.71 to 0.28 Mg m^?3 depending upon the degree of decomposition. Density of wood within large fallen logs varied with position relative to the ground and with distance from the center of the log. Densities for materials with diameters from 2 to 5 and 5 to 10 cm were 0.36 and 0.45 Mg m^?3, respectively. The average mass (±SE) of fallen CWD at Cauaxi was 55.2 (4.7), 74.7 (0.6), and 107.8 (10.5) Mg ha^?1 for duplicate UF, RIL, and CL sites, respectively. At Tapajós, the average mass of fallen CWD was 50.7 (1.1) Mg ha^?1 for UF and 76.2 (10.2) Mg ha^?1 for RIL for duplicate sites compared with 282 Mg ha^?1 for live aboveground biomass. Small‐ and medium‐sized material (<10 cm dia.) accounted for 8–18% of the total fallen CWD mass. The large amount of fallen CWD at these UF sites relative to standing aboveground biomass suggests either that the forests have recently been subjected to a pulse of high mortality or that they normally suffer a high mortality rate in the range of 0.03 per year. Accounting for background CWD in UF, CL management produced 2.7 times as much CWD as RIL management. Excess CWD at logging sites would generate a substantial CO₂ emission given the high rates of decay in moist tropical forests.     

The effect of income on the extraction of non-timber tropical forest products: Model,hypotheses, and preliminary findings from the Sumu Indians of Nicaragua

We use microeconomic theory to frame hypotheses about the effects of income on the use of non-timber rain forest products. We hypothesize that an increase in income: (a) encourages foraging specialization, resulting in the extraction of fewer goods; (b) increases the share of household income from occupations besides foraging; (c) produces a yearly value from the extraction of nontimber forest goods of about $50 per hectare; and (d) produces depletion of forest goods entering commercial channels and sustainable extraction of goods facing cheaper industrial substitutes. To examine these hypotheses we present worldwide ethnographic information and preliminary findings from field work carried out among the Sumu Indians of Nicaragua. Field work suggests that higher income produces: (a) foraging specialization with animals rather than with plants; (b) a decline in the economic importance of forest goods in household income; (c) and a rise in the value of non-timber goods removed from the forest to about $35/ha/year. We did not have time to test hypothesis d.     

Seasonal Foliage Changes in the Eastern Amazon Basin Detected from Landsat Thematic Mapper Satellite Images1

Seasonal changes in tropical forests are difficult to measure from the ground, especially in areas of high species diversity and low phenological synchrony. Satellite images, which integrate individual tree canopies and cover a large spatial extent, facilitate tests for stand-level canopy phenology. Variability in near-infrated radiance (TM bands 4 and 5) of several distinct vegetation types was used to detect seasonal changes in a series of three Landsat Thematic Mapper (TM) images from the wet season to the dry season in Marabá, Brazil (eastern Amazon basin). Despite different atmospheric and instrumental conditions among the images, spectral changes were distinguishable. A phenological process (leaf aging, leaf drop, water stress) was determined from the spectral changes for each vegetation type. Changes in the spectral properties suggest that during the dry season, upland terra firme forest increased the rate of leaf exchange and some riparian vegetation was deciduous. Terra firme forest that had been altered by penetration of fires from nearby pastures increased in leaf biomass over a 14-month period. This study shows that a time series of images can provide information on temporal changes in primary vegetation and guide field studies to investigate seasonal changes that may not be detectable from the ground.     

Demography of the vegetable ivory palm Phytelephas seemannii in Colombia, and the impact of seed harvesting

1. The demography of the vegetable ivory palm Phytelephas seemannii was studied on the Pacific coast of Colombia and a female-based matrix model was used to determine the proportion of seed that can be sustainably harvested from the population.
2. The density of the palm stands ranged from 240 to 420 adult palms ha⁻¹. The sex ratio was 1:1 and palms of both sexes produced leaves at the same rate. Seedlings produced 1·2 leaves per year on average, juveniles 1·8, and adults 6·1–7·4.
3. Adult females had fewer leaves than males (18·5 vs. 21·3 on average). Leaves of females lasted about 2·7 years in the crown, those of males about 3·2 years.
4. Stems creep on the ground, growing at the apex and often dying behind, the extant portion not always reflecting the palm's total age. The longest stem of a female palm in the study plots was 2·5 m, corresponding to an 'extant' age of 85 years; the longest stem recorded was that of a male (outside the plots) 10·5 m long, corresponding to an 'extant' age of 184 years. These figures reflect differences in growth habit, not in longevity.
5. Reproduction began at about 24 years, when the palm still lacked an above-ground stem.
6. The population growth rate λ was 1·059, and was most sensitive to changes in survival of juveniles and adults, and relatively insensitive to changes in fecundity and growth.
7. River channel migration is the most important cause of adult mortality. Phytelephas seemannii is apparently an efficient colonizer of the understorey in the late phases of riverine forest succession.
8. The population can tolerate a harvest intensity of 86% of all seeds before λ decreases to the equilibrium level of 1·00. Monitoring of the populations under intensive harvesting is required.     

Indigenous Land Use in the Ecuadorian Amazon: A Cross-cultural and Multilevel Analysis

Among the remaining tropical forests of lowland Latin America, many are inhabited by indigenous peoples, and the sustainability of their land uses is a point of heated debate in the conservation community. Numerous small-scale studies have documented changes in indigenous land use in individual communities in the context of expanding frontier settlements and markets, but few studies have included larger populations or multiple ethnic groups. In this paper we use data from a regional-scale survey of five indigenous populations in the Northern Ecuadorian Amazon to describe their agricultural land use practices and investigate the factors that affect those practices. We find the areas cultivated by indigenous households to be small compared to those of nearby mestizo colonists, but a large proportion of indigenous cultivated area is in commercial land uses. We also construct multilevel statistical models to investigate the household and community-level factors that affect indigenous land use. The results reveal significant influences on cultivated area from contextual factors such as access to markets, oil company activities, and the land tenure regime, as well as from household characteristics such as demographic composition, participation in alternative livelihood activities, and human, social and physical capitals. Overall the results are most consistent with market integration as an underlying driver of land use change in indigenous territories of the study area.

Distribution of aboveground live biomass in the Amazon basin

The amount and spatial distribution of forest biomass in the Amazon basin is a major source of uncertainty in estimating the flux of carbon released from land‐cover and land‐use change. Direct measurements of aboveground live biomass (AGLB) are limited to small areas of forest inventory plots and site‐specific allometric equations that cannot be readily generalized for the entire basin. Furthermore, there is no spaceborne remote sensing instrument that can measure tropical forest biomass directly. To determine the spatial distribution of forest biomass of the Amazon basin, we report a method based on remote sensing metrics representing various forest structural parameters and environmental variables, and more than 500 plot measurements of forest biomass distributed over the basin. A decision tree approach was used to develop the spatial distribution of AGLB for seven distinct biomass classes of lowland old‐growth forests with more than 80% accuracy. AGLB for other vegetation types, such as the woody and herbaceous savanna and secondary forests, was directly estimated with a regression based on satellite data. Results show that AGLB is highest in Central Amazonia and in regions to the east and north, including the Guyanas. Biomass is generally above 300 Mg ha⁻¹ here except in areas of intense logging or open floodplains. In Western Amazonia, from the lowlands of Peru, Ecuador, and Colombia to the Andean mountains, biomass ranges from 150 to 300 Mg ha⁻¹. Most transitional and seasonal forests at the southern and northwestern edges of the basin have biomass ranging from 100 to 200 Mg ha⁻¹. The AGLB distribution has a significant correlation with the length of the dry season. We estimate that the total carbon in forest biomass of the Amazon basin, including the dead and belowground biomass, is 86 Pg C with ±20% uncertainty.