Lower Madeira River Research Articles

Age, Religion, and Taboos Influence Subsistence Hunting by Indigenous People of the Lower Madeira River, Brazilian Amazon

Subsistence hunting is an essential livelihood strategy of Indigenous people in the Amazon. The present study examines the aspects influencing hunting practices by the Indigenous Maraguá people in the central Amazon, Brazil. We used a Generalized Additive Model to test the effects of economic (breeding of domestic animals), demographic (individual age), cultural (preference for hunting vs. fishing), and religious (Adventism, an Evangelical denomination vs. other Christian beliefs) factors on the frequency of hunting. We used a Principal Coordinate Analysis to assess how religious taboos associated with Adventism determine the composition of target taxa. The average hunting frequency of the 26 interviewees was 10.2 trips per month. Sixty-five percent (n = 17) of the interviewees were non-Adventists, and 35% (n = 9) were Adventists. Both younger and older people hunted less frequently than those in the middle age group (c. 50 years old). We found no influence of religious affiliation or breeding of domestic animals on the frequency of hunting. Ten taxa were cited as favorite game by the informants, and while Adventists avoided eating several mammalian taxa, non-Adventists did not declare any religious dietary restrictions. This study is one of the first to approach the influence of modern Christian belief systems on hunting habits of Indigenous Amazonian people. We highlight the importance of considering of cultural and religious particularities in research on subsistence hunting and design of management plans for Indigenous lands in Amazonia.

Genetics and telemetry indicate unexpected movements among structured populations for Brachyplatystoma platynemum in the Amazon.

The genetic analysis of Brachyplatystoma platynemum individuals sampled from the lower Madeira River reinforces the existence of two structured populations in the Amazon Basin (Madeira and Amazon populations). However, the recapture of an individual from the Amazon population in the Solimões River, which was telemetry-tagged in the Madeira River after the damming, indicates that fish from the Amazon population move between the two river systems. This has not yet been observed, however, in the Madeira River population, which is currently divided and isolated in the lower and upper Madeira River by the construction of two dams.

Indigenous Agency in the Amazon: The Mojos in Liberal and Rubber-Boom Bolivia, 1842–1932

“On a hot day in May 1887, a group of Bolivian soldiers halted their march across a flat savanna laced by lakes and tributaries of the Amazon. They were taking ten indigenous prisoners back to their headquarters in Trinidad, the local capital, but stopped to administer several hundred lashes to each. The soldiers took special delight in whipping an eighty-year-old man before finishing him off with gunshots. They saw the old man, Andrés Guayocho, not as the pathetic figure who begged them for a drink of water before dying, but as the leader of a major indigenous rebellion. . . . The local government ruthlessly crushed Guayocho’s millenarian movement not so much because of its religious unorthodoxy, but because it deprived the white elite of the Mojo labor necessary for the extraction and export of rubber for the world market.”Now that he has our attention, Gary Van Valen uses it well. The Mojos lived in savannas along the Mamoré River as it flows toward Brazil. From 1682 onward, they congregated onto Jesuit missions in what later became the Department of Beni. Van Valen traces their trajectory through the eighteenth and nineteenth centuries, particularly during the rubber boom (1875–1910) and its aftermath. He focuses on their agency in retaining their ethnic identity even as they accommodated the emerging Bolivian state. “Any attempt to renegotiate power relations is agency,” he writes, “from engagement in overt resistance such as a rebellion or millenarian movement, to the use of discourse, or language encoding a vision or plan for social relations. . . . By adapting to political and economic change, they remained Mojos.”In general, we know relatively little about western Amazonia during the century after 1787, when Jesuit missionaries were expelled from Spanish colonies. Van Valen provides a useful account of those “lost years.” By the 1860s, for example, several thousand Beni Indians worked for white patrones along the lower Madeira River and its tributaries—a generation before Indians in Peru, Ecuador, or Colombia underwent similar fates. Bolivian traders, borne by native paddlers, often made the round trip to Manaus loaded with agricultural products and returned with European manufactures. Until the 1880s, Van Valen writes, native people exercised considerable choice in escaping the tightening noose of taxation and repression in their homelands. After 1885, however, as the rubber boom quickened, their alternatives became much worse.And herein lies the problem with Van Valen’s view of agency. “There can be no doubt,” he writes, “that the former mission Indians of Beni suffered exploitation by the [whites] during the rubber boom—but it is equally true that the Indians were not helpless victims. They were constantly exercising their agency, looking out for their own best interests and choosing the best strategies for survival that their changing circumstances offered.” Of course, many people exercise some degree of choice within broader political, economic, and social conditions that lie completely beyond their control. But calling this kind of limited choice “agency” threatens to render the term analytically meaningless. It also ignores the millions who made a wrong choice—or no real choice at all—and disappeared from our analysis.Nonetheless, Van Valen has written a valuable book that should be widely read. It adds to our growing understanding of how groups like the Mojos endured forced labor, loss of land, oppressive taxation, and violent suppression during the late nineteenth and early twentieth centuries. The rubber boom was a needle’s eye through which they had to pass as they formulated their modern ethnic identity. Van Valen has given us another essential chapter in that story.

Household Agrobiodiversity Management on Amazonian Dark Earths, Oxisols, and Floodplain Soils on the Lower Madeira River, Brazil

Smallholder farmers play a critical role in the maintenance of global agrobiodiversity. However, the social and environmental factors that shape agrobiodiversity and its management in rural smallholder communities are still debated among scholars. This study examines variation in the diversity of useful plant species (i.e., species richness) managed by households located in three distinct environments along the Lower Madeira River in the Central Brazilian Amazon: Amazonian Dark Earths (ADE), upland Oxisols (OX), and floodplain soils (FP). Among the 106 households studied, those located on ADE managed a significantly higher number of useful species than those on floodplain soils but not than those on Oxisols. A generalized linear mixed effects model indicates that the age of the household head, number of household members and adults, and area of land under cultivation are statistically significant factors that influence species richness across all households. Ethnographic data are employed to contextualize these findings and discuss other influences on agrobiodiversity management in rural Amazonian communities, including regional historical ecology and the life histories of individual farmers.

Living between rapids: genetic structure and hybridization in botos (Cetacea: Iniidae:Iniaspp.) of the Madeira River, Brazil

Until the recent construction of hydroelectric dams, a series of 18 rapids divided the upper and lower Madeira River, and these rapids were thought to separate two species of Amazonian freshwater dolphins (boto): Inia boliviensis (above) and I. geoffrensis (below). Some reports and articles, however, mention the occurrence of botos within the rapids region and that they occasionally cross the rapids, but without mentioning the species concerned. Based on our previous studies, it is likely that I. boliviensis occurs in the region of the rapids. To test this supposition, we sampled 18 individuals from this region, and collected mitochondrial (control region, cytochrome b and cytochrome oxidase I) and nuclear (10 microsatellite loci) DNA data, in order to test if there is connectivity between the dolphins that were found within the rapids region and dolphins collected upstream and downstream of the rapids, and investigate population structuring between these localities. All animals in our study were molecularly identified using three mitochondrial markers as belonging to the species I. boliviensis. Animals upstream of the Teotonio waterfall, the main and highest waterfall of the region, had nuclear genome of I. boliviensis, while most dolphins downstream of the waterfall had nuclear genome of I. geoffrensis. Inia boliviensis collected in the rapids region above the Teotonio waterfall belong to a management unit (MU) distinct from the I. boliviensis MU occupying Bolivian rivers. Downstream of Teotonio waterfall most dolphins are I. boliviensis/geoffrensis hybrids, with remaining individuals being migrant I. boliviensis. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114, 764–777.

Provenance of sands from the confluence of the Amazon and Madeira rivers based on detrital heavy minerals and luminescence of quartz and feldspar

Source-to-sink systems are poorly known in tropical rivers. For the Amazonian rivers, the majority of the provenance studies remain focused on the suspended load, implying a poor understanding of the processes governing production and distribution of sands. In this study, we perform heavy mineral and optically stimulated luminescence (OSL) analysis to cover the entire spectrum (heavy and light minerals fraction) of 29 sand samples of the Lower Madeira river region (Amazon and Madeira rivers), of which the main goal was to find provenance indicators specific to these rivers. Despite the tropical humid climate, the sands of the Amazon and Lower Madeira rivers are rich in unstable heavy minerals as augite, hypersthene, green hornblende and andalusite. The Madeira river is highlighted by its higher content of andalusite, with source attributed to the Amazon Craton (medium-to-high grade metamorphic rocks), while the Amazon river, upstream of the Madeira river mouth, has a signature of augite and hypersthene, that suggests an Andean provenance (volcanic rocks). Sands from the Madeira river can be tracked in the Amazon river by the increasing concentration in andalusite. OSL analysis of the light minerals fraction was used as an index of feldspar concentration and sedimentary history of quartz grains. Lower feldspar concentration and quartz grains with longer sedimentary history (higher OSL sensitivity) also point to a major contribution of cratonic sources for the sands in the Madeira river. While the sands from the Lower Madeira would be mainly supplied by cratonic rocks, previous work recognised that suspended sediments (silt and clay) are derived from Andean rocks. Therefore, we interpret a decoupling between the sources of sand and mud (silt and clay) under transport in the Madeira river. Andean sands (rich in augite and hypersthene) would be trapped in the foreland zones of the Beni and Mamoré tributaries. In the Amazon river sands, the low OSL sensitivity of the quartz, higher content of feldspar and unstable heavy mineral assemblage dominated by augite and hypersthene suggest both a fast transport from Andean sources with fine sediment bypass over foreland areas.

Organização social baseada na lógica de cadeia-rede para potencializar a exploração do açaí nativo na Amazônia Ocidental Brasileira.

DOI: 10.5902/198346598903 The present paper has the objective to expose a proposition of organization within a chain and network logic, aiming to potentiate the extraction of the Native Açaí Berry at the Western Brazilian Amazon rainforest. This exploratory study involves the municipalities of Porto Velho, Guajará-Mirim and Machadinho D’Oeste, at the Brazilian state of Rondônia, with primary data originating mostly from conservation areas at the lower Madeira River region. As a result, it was possible to infer that from the native Açai Berry, derives food, pharmaceuticals and cosmetics, for both local consumption and international markets. It was found that beyond Açai Berry plantations availability, the lower Madeira River provides better transport logistic, consumer market and greater possibility of interaction with middleman than most Açai production areas. As a conclusion, it is made a proposition of an organizational arrangement to strengthen the extrativist productive chain of the Native Açaí Berry, based on the network and chain logic, oriented towards an organization based upon social organizations, manufacturing regularization and marketing.

Mercury in the environment and riverside population in the Madeira River Basin, Amazon, Brazil

This work presents quality control results on the mercury concentrations in different environmental (river sediments, forest soils, river suspended matter and fish) and human samples from the lower Madeira River, Amazon sampled between 2001 and 2003, about 15–20 years after the nearly cessation of gold mining activities in the region, which reached its peak in the late 1980s. The study aimed to compare mercury concentrations in these environmental samples with those reported by other authors during the gold rush of the Madeira River Basin. Today, in the Madeira River the releases of mercury register a sudden reduction due the gold price fall in the international trade. However, about 100 t of Hg were released to the atmosphere and to aquatic systems in the region during the gold rush. The present survey shows that notwithstanding the reduction of Hg emissions to the Madeira River Basin from gold mining proper, concentrations in fish and humans are similar to those measured during the gold rush. Reduction in Hg concentrations is restricted to areas close to old point sources and only for abiotic compartments (air and sediments). Remobilization of Hg from bottom sediments plus re-emission from soils due to land use changes are probably responsible for keeping high Hg concentrations in biological samples.

A new species of Echimys Cuvier, 1809 (Rodentia, Echimyidae) from Brazil

Here we describe a new species of Echimyidae Amazonian rodent, Echimys vieirai sp. nov., based on two individuals from the south bank of Amazon river between the lower Madeira river to the right bank of the Tapajós, respectively in the Brazilian states of Amazonas and Pará, Brazil. The main diagnostic characteristic of this new species is the presence of a dorsal median dark maroon stripe on the head, running from the rostrum to the nape. Skull morphology is quite similar to that of Echimys chrysurus (Zimmermann, 1780), but our new species differ from other species in the genus by the development of the alisphenoid canal and dp4 morphology. Additionally, we offer a refinement of the diagnosis of the genera Echimys and Makalata.

Description of a New Species of Pionopsitta (Aves: Psittacidae) Endemic to Brazil

Abstract A new species from Brazil—Pionopsitta aurantiocephala—is described, which is easily distinguished from the other species of that genus by its completely bare, intensely orange colored head. Specimens of this species have been historically identified as immatures of P. vulturina, which occur in simpatry with P. aurantiocephala on the Middle Tapajós River and possibly on the Lower Madeira River. The description of a new species of Psittacidae stresses the importance of new studies in the regions of the Madeira and Tapajós rivers.

Description of a New Species of Pionopsitta (Aves: Psittacidae) Endemic to Brazil

Abstract A new species from Brazil—Pionopsitta aurantiocephala—is described, which is easily distinguished from the other species of that genus by its completely bare, intensely orange colored head. Specimens of this species have been historically identified as immatures of P. vulturina, which occur in simpatry with P. aurantiocephala on the Middle Tapajos River and possibly on the Lower Madeira River. The description of a new species of Psittacidae stresses the importance of new studies in the regions of the Madeira and Tapajos rivers.