Amazonian Sites Research Articles

Effects of forest degradation classification on the uncertainty of aboveground carbon estimates in the Amazon

BackgroundTropical forests are critical for the global carbon budget, yet they have been threatened by deforestation and forest degradation by fire, selective logging, and fragmentation. Existing uncertainties on land cover classification and in biomass estimates hinder accurate attribution of carbon emissions to specific forest classes. In this study, we used textural metrics derived from PlanetScope images to implement a probabilistic classification framework to identify intact, logged and burned forests in three Amazonian sites. We also estimated biomass for these forest classes using airborne lidar and compared biomass uncertainties using the lidar-derived estimates only to biomass uncertainties considering the forest degradation classification as well.ResultsOur classification approach reached overall accuracy of 0.86, with accuracy at individual sites varying from 0.69 to 0.93. Logged forests showed variable biomass changes, while burned forests showed an average carbon loss of 35%. We found that including uncertainty in forest degradation classification significantly increased uncertainty and decreased estimates of mean carbon density in two of the three test sites.ConclusionsOur findings indicate that the attribution of biomass changes to forest degradation classes needs to account for the uncertainty in forest degradation classification. By combining very high-resolution images with lidar data, we could attribute carbon stock changes to specific pathways of forest degradation. This approach also allows quantifying uncertainties of carbon emissions associated with forest degradation through logging and fire. Both the attribution and uncertainty quantification provide critical information for national greenhouse gas inventories.

Species richness of Antbirds (Thamnophilidae) in more central and peripheral sites of terra firme forest in the eastern edge of the Amazonia

Antbirds (Thamnophilidae) comprise many insectivorous, mostly understory birds present in all Neotropical biomas. Many species occur specifically in the Amazonia, so a decline in species richness is expected from central Amazonian sites, to peripheral ones; this pattern is due primarily to the evolutionary history of the taxon. Rapid surveys to state the antbird species richness were performed in six sites of terra firme forest in the Belém Center of Endemism, the Easternmost and one of the most threatened regions in the Amazonia. These sites followed a series from more central to more peripheral areas, the latter being located in the edge of the Amazonia. The antbird species richness of every site was stated by presence-absence criteria. Two surveys were made in each site, by walking three transects in each of two trails in every survey. This species richness progressively fell from 19 species in the most central site (Gurupi Biological Reserve) to only two in the most peripheral one (São Luís). Probably, the gradient in the species richness is primarily associated to the evolutionary history of this group, however new studies using methods appropriated to assess the effects of environmental degradation in the regional richness of Thamnophilidae and other forest bird species should be encouraged.

Relationship between Land Use and Spatial Variability of Atmospheric Brown Carbon and Black Carbon Aerosols in Amazonia

The aerosol radiative effect is an important source of uncertainty in estimating the anthropogenic impact of global climate change. One of the main open questions is the role of radiation absorption by aerosols and its relation to land use worldwide, particularly in the Amazon Rainforest. Using AERONET (Aerosol Robotic Network) long-term measurements of aerosol optical depth (AOD) at a wavelength of 500 nm and absorption AOD (AAOD) at wavelengths of 440, 675, and 870 nm, we estimated the fraction and seasonality of the black carbon (BC) and brown carbon (BrC) contributions to absorption at 440 nm. This was conducted at six Amazonian sites, from central Amazon (Manaus and the Amazon Tall Tower Observatory—ATTO) to the deforestation arc (Rio Branco, Cuiabá, Ji-Paraná, and Alta Floresta). In addition, land use and cover data from the MapBiomas collection 6.0 was used to access the land transformation from forest to agricultural areas on each site. The results showed, for the first time, important geographical and seasonal variability in the aerosol optical properties, particularly the BC and BrC contributions. We observed a clear separation between dry and wet seasons, with BrC consistently accounting for an average of approximately 12% of the aerosol AAOD at 440 nm in the deforestation arc. In central Amazon, the contribution of BrC was approximately 25%. A direct relationship between the reduction in forests and the increase in the area dedicated to agriculture was detected. Moreover, places with lower fractions of forest had a smaller fraction of BrC, and regions with higher fractions of agricultural areas presented higher fractions of BC. Therefore, significant changes in AOD and AAOD are likely related to land-use transformations and biomass burning emissions, mainly during the dry season. The effects of land use change could introduce differences in the radiative balance in the different Amazonian regions. The analyses presented in this study allow a better understanding of the role of aerosol emissions from the Amazon Rainforest that could have global impacts.

Do you dig your grave with your teeth? Potential interest of the elementary analysis of ancient ceramics regarding public health (Pre-Columbian era, Ecuador)

Following several studies considering the potential toxicity of food-type containers, we hypothesized elemental analysis would help us test and classify a collection of Ecuadorian ceramic sherds from Andean and Amazonian sites. μ-XRF spectrometer analyses were carried out on 48 ceramic sherds coming from 4 different archaeological sites. Major elements values were transformed into oxides and data were constrained to 100%, making our results semi-quantitative. A principal component analysis (PCA) was then performed on the additive log-ratio (ALR) transformed data to identify main compositional axes and plot the sherds. Besides, a hierarchical cluster analysis (HCA) was applied on the coordinates of the individuals from the PCA to estimate the chemical similarity between the ceramic samples. The lead detected on the internal face of the ceramics locally produced in Quito was generally below the limit of quantification, while the lead concentration mean in the Cosanga ceramics was 180 ± 34 μg/g. The lead concentration values in the Pucará ceramics and the type labelled Mango Montaño were of the same order. Arsenic, mercury, cobalt, chromium and antimony values proved to be below the quantification limits. The PCA on the ALR transformed data evidenced 2 main axes. The first main axis PC1 made it possible to graphically distinguish the “local Quito” ceramics from the “Cosanga” ceramics. The second main axis PC2 made it possible to refine the distribution of the samples. Three of four samples from Pucará were close to the ceramics locally produced in Quito. The HCA was applied on the first five factors to take into account about 80% of the total variance of the sample set. The dendrogram discriminated two main clusters, demonstrating a significant clustering pattern of certain fragments belonging to the same craft tradition, essentially the Cosanga ceramics vs. the Local Quito ones. No particular hazard was identified regarding the exposure of past populations to potentially toxic pottery. We managed through elemental analysis followed by a principal component analysis and a graphic representation to clearly identify 2 groups of pottery out of 4 different locations, 3 different periods and 4 cultural traditions corresponding to 4 different populations. We aim in the near future at testing the samples we presented for lead leachability and comparing them with ceramic samples from other locations.

Species-rich but defaunated: the case of medium and large-bodied mammals in a sustainable use protected area in the Amazon

ABSTRACT Neotropical medium and large-bodied mammals are key elements in forest ecosystems, and protected areas are essential for their conservation. In Brazil, sustainable use protected areas (SU-PAs) allow both the conservation of biodiversity and the sustainable use of natural resources, especially in the Amazon region. However, SU-PAs usually suffer both internal and external pressures, and may be subject to variable degrees of defaunation. We sampled mammals using camera traps in two areas with different forest management and human occupation history in the Tapajós National Forest (TNF), in the western Amazon. Overall, we recorded a rich assemblage of medium and large-sized mammals, though both areas differed in species composition. The area with older and more intense human occupation and forest exploitation had more independent records of generalist species, while large species such as Tapirus terrestris and Panthera onca were recorded exclusively in the area with lower human occupation and no forest management. A comparison of our results with similar studies in other Amazonian sites suggests a reduction in the population size of large-bodied mammals, such as Tapirus terrestris and Tayassu pecari, likely in response to increased human activities. Local differences in human occupation within and between protected areas are common in the Amazon, demanding area-specific actions from public authorities to minimize impacts on wildlife caused by human activities. Specifically in TNF, we recommend long-term monitoring of the responses of mammals to human activities, to better subsidize conservation and management actions.

Wild meat consumption in tropical forests spares a significant carbon footprint from the livestock production sector

Whether sustainable or not, wild meat consumption is a reality for millions of tropical forest dwellers. Yet estimates of spared greenhouse gas (GHG) emissions from consuming wild meat, rather than protein from the livestock sector, have not been quantified. We show that a mean per capita wild meat consumption of 41.7 kg yr−1 for a population of ~ 150,000 residents at 49 Amazonian and Afrotropical forest sites can spare ~ 71 MtCO2-eq annually under a bovine beef substitution scenario, but only ~ 3 MtCO2-eq yr−1 if this demand is replaced by poultry. Wild meat offtake by these communities could generate US$3M or US$185K in carbon credit revenues under an optimistic scenario (full compliance with the Paris Agreement by 2030; based on a carbon price of US$50/tCO2-eq) and US$1M or US$77K under a conservative scenario (conservative carbon price of US$20.81/tCO2-eq), representing considerable incentives for forest conservation and potential revenues for local communities. However, the wild animal protein consumption of ~ 43% of all consumers in our sample was below the annual minimum per capita rate required to prevent human malnutrition. We argue that managing wild meat consumption can serve the interests of climate change mitigation efforts in REDD + accords through avoided GHG emissions from the livestock sector, but this requires wildlife management that can be defined as verifiably sustainable.

Amazonia as a carbon source linked to deforestation and climate change.

Amazonia hosts the Earth's largest tropical forests and has been shown to be an important carbon sink over recent decades1-3. This carbon sink seems to be in decline, however, as a result of factors such as deforestation and climate change1-3. Here we investigate Amazonia's carbon budget and the main drivers responsible for its change into a carbon source. We performed 590 aircraft vertical profiling measurements of lower-tropospheric concentrations of carbon dioxide and carbon monoxide at four sites in Amazonia from 2010 to 20184. We find that total carbon emissions are greater in eastern Amazonia than in the western part, mostly as a result of spatial differences in carbon-monoxide-derived fire emissions. Southeastern Amazonia, in particular, acts as a net carbon source (total carbon flux minus fire emissions) to the atmosphere. Over the past 40 years, eastern Amazonia has been subjected to more deforestation, warming and moisture stress than the western part, especially during the dry season, with the southeast experiencing the strongest trends5-9. We explore the effect of climate change and deforestation trends on carbon emissions at our study sites, and find that the intensification of the dry season and an increase in deforestation seem to promote ecosystem stress, increase in fire occurrence, and higher carbon emissions in the eastern Amazon. This is in line with recent studies that indicate an increase in tree mortality and a reduction in photosynthesis as a result of climatic changes across Amazonia1,10.

Reconstructing freshwater fishing seasonality in a neotropical savanna: First application of swamp eel (Synbranchus marmoratus) sclerochronology to a pre-Columbian Amazonian site (Loma Salvatierra, Bolivia)

Sclerochronology is a method used to estimate the season of death (season of capture) of archaeological individuals based on a modern growth model. This method has been increasingly accepted in South America and has mainly been applied to coastal archaeological sites (on the Atlantic and Pacific Oceans). This is the first time that this method has been applied to a freshwater species, the marbled swamp eel (Synbranchus marmoratus), in archaeology. Excavations undertaken at Loma Salvatierra, a human-built platform located in the Bolivian Amazon and occupied from 500 until 1400 CE, have yielded 111 zooarchaeological vertebrae of the marbled swamp eel, which is one of the most widely distributed species recovered in South American continental archaeological sites. In order to estimate the fishing season for these archaeological individuals, we developed a modern osteological reference collection, made up of 61 specimens with known capture dates sampled monthly over a one-year period, about 60 km from Loma Salvatierra. The vertebrae present periodic growth patterns with a succession of dark and light bands alternately. Consequently, the vertebrae are a reliable basis for the estimation of the marbled swamp eel fishing season. The analysis of the marginal increments of vertebrae in present-day fish allowed us to elaborate a modern growth model showing that the seasonal growth of the marbled swamp eel is related to the hydrological cycle, whereby the fast growth period coincides with the onset of rainfall in the region. On the basis of this modern-based model, the analysis of zooarchaeological vertebrae demonstrates that fish were captured over several seasons. Demonstrating that human groups occupied villages year-round does not mean that they were not mobile but shows year-round fishing in the savanna. This year-round fishing practice raises questions concerning the generalized idea of fishing as an exclusively dry-season activity. As wild resources are generally seasonal, the evidence of the year-round fishing of swamp eels might suggest year-round fishing at Loma Salvatierra and contributes to the understanding of late-Holocene mobility patterns in pre-Columbian times.

Activity patterns of jaguar and puma and their main prey in the Greater Madidi-Tambopata Landscape (Bolivia, Peru)

Abstract Activity pattern studies can help explain the coexistence of competing species. Between 2001 and 2017 we evaluated the activity pattern overlap of jaguar (Panthera onca), puma (Puma concolor), and their main prey, using camera traps at 17 Amazonian sites in the Greater Madidi-Tambopata Landscape. We used the Kernel density estimation to generate species activity patterns and the overlap between both cats. We then calculated the overlap coefficient (Δ) by carrying out 10,000 bootstraps (95%). Both cats were active 24 h a day. The puma has higher nocturnal activity (57%), whilst jaguar activity is split almost equally between night (53%) and day (47%). We did not find temporal segregation between jaguars and pumas, which showed similar activity patterns with a high overlapping coefficient (Δ4 = 0.84; 0.78–0.91). Also, we did not find significant differences between Male and Female activity patterns for both species (X2 = 0.50, gl = 1, P = 0.47). Moreover, both cats had significant overlap with the activity patterns of their main prey. Temporal segregation was not detected in any of our study sites within the Greater Madidi-Tambopata Landscape, suggesting that in this region, these predators employ other mechanisms to avoid competition.

Involving local communities for effective citizen science: Determining game species' reproductive status to assess hunting effects in tropical forests

Abstract Involving communities in sustainable wildlife management in tropical forests can ensure food security and livelihoods of millions of forest dwellers that depend on wild meat, and also safeguard hunted species. Mathematical models have been developed to assess hunting sustainability; but these require empirical information on reproductive parameters of the prey species, often challenging to obtain. Here, we suggest that if local people can accurately identify the reproductive status of hunted animals in the field, these data could fill the existing knowledge gap regarding species' life‐history traits and enable better assessments of hunting impacts. We first tested whether local people in 15 rural communities in three Amazonian sites could accurately diagnose, before and after training, the pregnancy status of hunted pacas Cuniculus paca, which we use as our model. We then applied the results from these tests to correct reproductive status data of hunted specimens, voluntarily collected over 17 years (2002–2018) as part of a citizen-science project in one of our study sites. We ran generalized additive models to contrast these corrected reproductive rates with those obtained from the direct analysis of genitalia by researchers, and with indices describing game extraction levels (catch‐per‐unit‐effort, CPUE, and age structure of hunted individuals). Before training, interviewees correctly diagnosed pregnancy in 72.5% of tests, but after training, interviewees accurately diagnosed pregnancy in 88.2% of tests, with high improvements especially for earlier pregnancy stages. Monthly pregnancy rates determined by hunters and by researchers were similar. Reported annual pregnancy rates were negatively correlated with CPUE, and positively correlated with the percentage of immatures in the hunted population, in accordance with an expected density‐dependent response to variations in hunting levels. Synthesis and applications. We show that the voluntary diagnosis of game species' reproductive status by local people is a feasible method to obtain accurate life‐history parameters for hunted tropical species, and to assess hunting effects on game populations. Given that almost half of the protected areas in the world are co‐managed by local people, our results confirm the potential of integrating local communities in citizen-science initiatives to ensure faster, low‐cost and more accurate data collection for wildlife management.

New populations of pampas deer Ozotoceros bezoarticus discovered in threatened Amazonian savannah enclaves

AbstractThe savannah enclaves (i.e. patches) in the southern Brazilian Amazonia are among the most threatened and poorly surveyed sites in Amazonia. As part of an extensive mammal survey, we set camera traps in three of these savannah enclaves. We obtained 23 independent records of pampas deer Ozotoceros bezoarticus, a medium sized Neotropical cervid that is strongly associated with open habitats and categorized as Vulnerable on the Brazilian Red List of threatened species. These savannah enclaves with confirmed populations of pampas deer lie outside the species’ previously presumed historical range and are at least 350 km from any known extant population. Together, these savannah enclaves add c. 4,000 km2 to the pampas deer's currently known range. The small pampas deer populations in these enclaves are probably isolated by a matrix of Amazon forest, raising questions about spatial genetic structure and meta-population dynamics, and making them vulnerable to local extinction. We highlight the need for further studies, particularly genetic, to assess the conservation status of these populations, the results of which could potentially inform management decisions in other areas of the heavily fragmented range of this species.

Local Convection and Turbulence in the Amazonia Using Large Eddy Simulation Model

Using a high resolution model of Large Eddies Simulation (LES), named PALM from PArallel LES Model, a set of simulations were performed to understand how turbulence and convection behave in a pasture and forest sites in Amazonia during the dry and rainy seasons. Related to seasonality, dry period presented higher differences of values (40 W m−2) and patterns over the sites, while in the wet period have more similar characteristics (difference of −10 W m−2). The pasture site had more convection than the forest, with effective mixing and a deeper boundary layer (2600 m). The vertical decrease of sensible heat flux with altitude fed convection and also influenced the convective boundary layer (CBL) height. Regarding the components of turbulent kinetic energy equation, the thermal production was the most important component and the dissipation rate responded with higher growth, especially in cases of greatest mechanical production at the forest surface reaching values up to −20.0.

Breeding seasonality in the lowland paca (Cuniculus paca) in Amazonia: interactions with rainfall, fruiting, and sustainable hunting

Abstract The resilience of a given species to hunting is conditioned by the effect of potential threats upon the more sensitive periods in its life history, such as when animals are breeding. We investigated the environmental drivers of breeding seasonality in the lowland paca (Cuniculus paca), and the potential impact of hunting on the species. As part of a participative study with hunters in 2 Amazonian sites, we obtained reproductive organs of pacas as well as information on the hunters’ daily wild meat extraction. Using data on rainfall, river water level, and fruiting phenology from the 2 study sites, we applied generalized additive models for location, scale, and shape (GAMLSS) to examine the effect of climatic and environmental factors on paca reproduction. Forest fruiting was directly linked to higher pregnancy rates in pacas, and when lactation and weaning of offspring mostly occurred. Hunting was highly seasonal in all studied years and positively correlated with higher levels of river water. The coincidence between hunting patterns and paca reproductive cycles during the wet season resulted in more pregnant females being harvested. In addition to the known slow reproductive rate of pacas, the disproportionate offtake of pregnant females may affect the long-term sustainability of hunting of this species. Reducing hunting during the flooded season may not be feasible because the lowland paca provides most of the wild meat consumed by thousands of rural Amazonians during this period. However, options to offset the negative effects of killing of pregnant females could include the zoning of hunting areas or encouraging hunters to target primarily males. Our results indicate that strategies for the sustainable harvest of pacas and other heavily hunted Amazonian mammals should consider the interaction between the species’ reproductive cycles and hunting by local people in order to enhance conservation and management efforts. A resiliência de uma espécie à caça é condicionada pela sua capacidade reprodutiva intrínseca e pelo efeito de potenciais ameaças durante os períodos mais sensíveis de sua história de vida, como o período reprodutivo. Neste trabalho, nós investigamos os fatores ambientais que determinam a sazonalidade reprodutiva da paca (Cuniculus paca) e o potencial impacto da caça sobre a espécie. Em um estudo participativo de 15 anos em duas áreas da Amazônia, obtivemos órgãos reprodutivos de pacas doados voluntariamente por caçadores, bem como informações sobre seus padrões diários de caça. Usando informações sobre precipitação, nível d’água dos rios e fenologia de frutificação, nós aplicamos modelos aditivos generalizados (GAMLSS) para examinar o efeito de fatores climáticos e ambientais na reprodução da paca. A precipitação esteve positivamente ligada a uma maior frutificação, que por sua vez foi correlacionada com maiores taxas de prenhes da paca e com os períodos de lactação e desmame da prole. A caça de paca foi altamente cíclica ao longo dos anos e positivamente associada aos níveis d’água mais elevados. A convergência entre os padrões de caça e os ciclos reprodutivos de paca resulta na extração de um grande número de fêmeas grávidas. Juntamente com a lenta taxa de reprodução da espécie, a captura desproporcional de fêmeas grávidas pode afetar a sustentabilidade do uso da paca. Reduzir a caça durante os períodos de inundação pode não ser viável, pois a paca é a espécie responsável por fornecer grande parte da carne silvestre consumida por milhares de moradores rurais da Amazônia neste período. No entanto, ações para compensar os efeitos negativos da extração de pacas grávidas poderiam incluir o zoneamento de áreas de caça ou o incentivo aos caçadores em abater preferencialmente machos. Nossos resultados indicam que estratégias para a extração sustentável da paca e outras espécies cinegéticas amazônicas devem considerar a interação entre a reprodução e a caça pela população local, a fim de melhorar as ações de conservação e manejo no bioma.

Using DNA metabarcoding for simultaneous inference of common vampire bat diet and population structure.

Metabarcoding diet analysis has become a valuable tool in animal ecology; however, co‐amplified predator sequences are not generally used for anything other than to validate predator identity. Exemplified by the common vampire bat, we demonstrate the use of metabarcoding to infer predator population structure alongside diet assessments. Growing populations of common vampire bats impact human, livestock and wildlife health in Latin America through transmission of pathogens, such as lethal rabies viruses. Techniques to determine large‐scale variation in vampire bat diet and bat population structure would empower locality‐ and species‐specific projections of disease transmission risks. However, previously used methods are not cost‐effective and efficient for large‐scale applications. Using bloodmeal and faecal samples from common vampire bats from coastal, Andean and Amazonian regions of Peru, we showcase metabarcoding as a scalable tool to assess vampire bat population structure and feeding preferences. Dietary metabarcoding was highly effective, detecting vertebrate prey in 93.2% of the samples. Bats predominantly preyed on domestic animals, but fed on tapirs at one Amazonian site. In addition, we identified arthropods in 9.3% of samples, likely reflecting consumption of ectoparasites. Using the same data, we document mitochondrial geographic population structure in the common vampire bat in Peru. Such simultaneous inference of vampire bat diet and population structure can enable new insights into the interplay between vampire bat ecology and disease transmission risks. Importantly, the methodology can be incorporated into metabarcoding diet studies of other animals to couple information on diet and population structure.

Historical Archaeology in the Amazon: the Murutucu Sugar Cane Mill Field School Project

Based on research on the Murutucu Sugar Cane Mill Field School Project in Belem City, Para State, Brazil, this article presents a novel approach to historical archaeology in the Amazon. An anthropological view is described with a focus on ethnic, social, economic, political, gender, and generational groups. Although archaeology in the Amazon has a long tradition of more than 150 years of research, most studies on the region examine precontact sites. In contrast, the few pioneering studies on Amazonian historical sites have pursued chronological and technological objectives and have been primarily restricted to military and religious sites.

Persistent effects of pre-Columbian plant domestication on Amazonian forest composition.

The extent to which pre-Columbian societies altered Amazonian landscapes is hotly debated. We performed a basin-wide analysis of pre-Columbian impacts on Amazonian forests by overlaying known archaeological sites in Amazonia with the distributions and abundances of 85 woody species domesticated by pre-Columbian peoples. Domesticated species are five times more likely than nondomesticated species to be hyperdominant. Across the basin, the relative abundance and richness of domesticated species increase in forests on and around archaeological sites. In southwestern and eastern Amazonia, distance to archaeological sites strongly influences the relative abundance and richness of domesticated species. Our analyses indicate that modern tree communities in Amazonia are structured to an important extent by a long history of plant domestication by Amazonian peoples.

Vegetation chlorophyll estimates in the Amazon from multi-angle MODIS observations and canopy reflectance model

As a preparatory study for future hyperspectral missions that can measure canopy chemistry, we introduce a novel approach to investigate whether multi-angle Moderate Resolution Imaging Spectroradiometer (MODIS) data can be used to generate a preliminary database with long-term estimates of chlorophyll. MODIS monthly chlorophyll estimates between 2000 and 2015, derived from a fully coupled canopy reflectance model (ProSAIL), were inspected for consistency with eddy covariance fluxes, tower-based hyperspectral images and chlorophyll measurements. MODIS chlorophyll estimates from the inverse model showed strong seasonal variations across two flux-tower sites in central and eastern Amazon. Marked increases in chlorophyll concentrations were observed during the early dry season. Remotely sensed chlorophyll concentrations were correlated to field measurements (r2=0.73 and r2=0.98) but the data deviated from the 1:1 line with root mean square errors (RMSE) ranging from 0.355μgcm−2 (Tapajós tower) to 0.470μgcm−2 (Manaus tower). The chlorophyll estimates were consistent with flux tower measurements of photosynthetically active radiation (PAR) and net ecosystem productivity (NEP). We also applied ProSAIL to mono-angle hyperspectral observations from a camera installed on a tower to scale modeled chlorophyll pigments to MODIS observations (r2=0.73). Chlorophyll pigment concentrations (ChlA+B) were correlated to changes in the amount of young and mature leaf area per month (0.59≤r2≤ 0.64). Increases in MODIS observed ChlA+B were preceded by increased PAR during the dry season (0.61≤r2≤ 0.62) and followed by changes in net carbon uptake. We conclude that, at these two sites, changes in LAI, coupled with changes in leaf chlorophyll, are comparable with seasonality of plant productivity. Our results allowed the preliminary development of a 15-year time series of chlorophyll estimates over the Amazon to support canopy chemistry studies using future hyperspectral sensors.

Analysis of biological and meteorological controls of evapotranspiration in pristine forests and a pasture site in Amazonia

This work studied the behavior and seasonality of evapotranspiration influenced by biotic and abiotic factors through analysis of diurnal variation of aerodynamic resistance (ra), stomatal resistance (rs) and decoupling factor (Ω). This index was proposed by Jarvis and McNaughton (1986) as an indicative of the control of these resistances on the evapotranspiration of vegetation. Selection of representative data from wet and dry seasons from a primary forest in Central Amazonia and a primary forest and a pasture sites in Southwestern Amazonia had shown that: (i) ra is about 20 s.m-1 in both forests in both seasons, and ranges from 70 to 100 s.m-1 in the pasture site; (ii) rs varies both throughout the day and seasonally, with medians increasing from 40 in the morning, to 150 s.m-1 in late afternoon, in the wet season in the forests and from 50 to 160 s.m-1 in the pasture. These values increase in the dry season, with the forests rs ranging from 50 up to 500 s.m-1 and pasture rs starting from 140 s.m‑1 and reaching up to more than 1800 s.m-1 in the dry afternoons; (iii) Ω ranges from 0.5 to 0.8 during the wet season, and reduces to values below 0.5 in the afternoons during the dry season, indicating that, although a strong influence of net radiation in the evaporative loss is present, to a large extent the evapotranspiration fluxes are coupled to the biotic control of stomatal closure in the vegetation, especially in the pasture and during dry periods.

Study of exchange networks between two Amazon archaeological sites by INAA

This work comprises the utilization of instrumental neutron activation analysis to determine the concentration of 24 chemical elements in pottery shards from two large archaeological sites in central Amazon, Lago Grande and Osvaldo. The multidimensional data set was analyzed by cluster and principal component analysis for defining chemical groups of pottery. The results were correlated to potential exchange networks driven by three mechanisms: trade, exogamic marriage and territorial integration in the region. All of them have important consequences for archaeological research regarding the Amazonian pre-colonial occupation.

Fruits eaten by woolly monkeys (Lagothrix lagothricha) at local and regional scales.

Woolly monkeys are endangered New World Primates whose natural ecological requirements are known from few sites. This study aimed to investigate the diet of woolly monkeys (Lagothrix lagothricha, Atelidae) to examine how availability determines fruit choice at local and regional scales. We followed two groups of woolly monkeys in the Mosiro Itajura-Caparú biological station in the Colombian Amazon for 16months, and then compared our observations with previous studies for this and other sites in the Amazon and eastern Andes. We found a high prevalence of fruits in the diet of woolly monkeys in Caparú, which was supplemented with arthropods and leaves. This pattern was observed in all age/sex classes, although juveniles ate more arthropods, and females with dependent young ate more leaves than other classes. We suggest these differences might be due to intragroup competition and particular nutritional requirements in each age/sex class. When comparing the fruit diet composition in Caparú (>190 species) with four other places, we found that Moraceae, Fabaceae, and Sapotaceae were consistently important tree families in the Amazonian sites, and that forest richness is a good predictor of the diet richness. Overall, the results support the hypothesis that woolly monkeys are opportunistic frugivores that are able to adapt their diet to the forest supply and to the temporal variation in resource availability.