Spatial modeling of deforestation processes in the Central Peruvian Amazon

This study examines the relation between primary forest loss and landscape characteristics in the Ucayali region, Peru. Seven variables (rivers, elevation, annual precipitation, soil suitability for agriculture, population density, paved roads, and unpaved roads), were identified as potential deforestation drivers. The variables were converted into spatially explicit layers of continuous data and divided into a 9 km² grid. A multiple regression analysis was conducted to determine variable significance. Distance to paved and unpaved roads were strongly associated with deforestation, followed by distance to rivers, annual precipitation and elevation. All significant variables were negatively correlated with deforestation. Variables excluded from the model were population density and soil suitability for agriculture, suggesting that the influence of population density on forest clearing across the study area was not significant, and that deforestation activities were undertaken regardless whether soils are suitable for agriculture or not. Based on the linear regression analysis, the significant variables were selected and added to the Land Change Modeler in order to project primary forest coverage by 2025. The modeling results predict extensive deforestation along the Aguaytia River and at the forest/non-forest interface along the paved highway. The rate of primary forest removal is expected to increase from 4783 ha y⁻¹ (for the 2007–2014 period) to 5086 ha y⁻¹ (for the 2015–2025 period). A preliminary survey questionnaire conducted to explore deforestation intentions by farmers in the region, partly confirmed the overall deforestation trends as projected by the model.     

Lightning-caused disturbance in the Peruvian Amazon

We surveyed seven lightning strike sites in the northern Peruvian Amazon. An average of 17.3 trees were damaged per strike; large trees (> 60 cm diameter) were disproportionately affected. The results contribute to a growing body of evidence that lightning is an important agent of disturbance pantropically. Abstract in Spanish is available with online material.     

Three days for weeping: dreams,emotions, and death in the Peruvian Amazon

Funeral customs and beliefs about the dead among the Matsigenka of Peru reflect great anxiety over the contagion of death and the power of the dead over the living. In this article, these beliefs and practices are interpreted in light of a native theory about emotion. For the Matsigenka, excessive displays of emotion, especially grief, anger, and aggressive sexuality, cause a vicious cycle of unhappiness, social disruption, illness, and death. Moving beyond a culturally particular, symbolic-interpretive perspective, the author also draws on personal experiences both in the field and at home to reflect on the phenomenology of grief across cultures.     

Characterizing a tropical deforestation wave: a dynamic spatial analysis of a deforestation hotspot in the Colombian Amazon

Tropical deforestation is the major contemporary threat to global biodiversity, because a diminishing extent of tropical forests supports the majority of the Earth's biodiversity. Forest clearing is often spatially concentrated in regions where human land use pressures, either planned or unplanned, increase the likelihood of deforestation. However, it is not a random process, but often moves in waves originating from settled areas. We investigate the spatial dynamics of land cover change in a tropical deforestation hotspot in the Colombian Amazon. We apply a forest cover zoning approach which permitted: calculation of colonization speed; comparative spatial analysis of patterns of deforestation and regeneration; analysis of spatial patterns of mature and recently regenerated forests; and the identification of local‐level hotspots experiencing the fastest deforestation or regeneration. The colonization frontline moved at an average of 0.84 km yr^?1 from 1989 to 2002, resulting in the clearing of 3400 ha yr^?1 of forests beyond the 90% forest cover line. The dynamics of forest clearing varied across the colonization front according to the amount of forest in the landscape, but was spatially concentrated in well‐defined ‘local hotspots’ of deforestation and forest regeneration. Behind the deforestation front, the transformed landscape mosaic is composed of cropping and grazing lands interspersed with mature forest fragments and patches of recently regenerated forests. We discuss the implications of the patterns of forest loss and fragmentation for biodiversity conservation within a framework of dynamic conservation planning.     

Forest Canopy Gap Distributions in the Southern Peruvian Amazon

Canopy gaps express the time-integrated effects of tree failure and mortality as well as regrowth and succession in tropical forests. Quantifying the size and spatial distribution of canopy gaps is requisite to modeling forest functional processes ranging from carbon fluxes to species interactions and biological diversity. Using high-resolution airborne Light Detection and Ranging (LiDAR), we mapped and analyzed 5,877,937 static canopy gaps throughout 125,581 ha of lowland Amazonian forest in Peru. Our LiDAR sampling covered a wide range of forest physiognomies across contrasting geologic and topographic conditions, and on depositional floodplain and erosional terra firme substrates. We used the scaling exponent of the Zeta distribution (λ) as a metric to quantify and compare the negative relationship between canopy gap frequency and size across sites. Despite variable canopy height and forest type, values of λ were highly conservative (λ _mean  = 1.83, s  = 0.09), and little variation was observed regionally among geologic substrates and forest types, or at the landscape level comparing depositional-floodplain and erosional terra firme landscapes. λ-values less than 2.0 indicate that these forests are subjected to large gaps that reset carbon stocks when they occur. Consistency of λ-values strongly suggests similarity in the mechanisms of canopy failure across a diverse array of lowland forests in southwestern Amazonia.     

Population Genetics of Plasmodium vivax in the Peruvian Amazon

Background

Characterizing the parasite dynamics and population structure provides useful information to understand the dynamic of transmission and to better target control interventions. Despite considerable efforts for its control, vivax malaria remains a major health problem in Peru. In this study, we have explored the population genetics of Plasmodium vivax isolates from Iquitos, the main city in the Peruvian Amazon, and 25 neighbouring peri-urban as well as rural villages along the Iquitos-Nauta Road.

Methodology/ Results

From April to December 2008, 292 P. vivax isolates were collected and successfully genotyped using 14 neutral microsatellites. Analysis of the molecular data revealed a similar proportion of monoclonal and polyclonal infections in urban areas, while in rural areas monoclonal infections were predominant (p = 0.002). Multiplicity of infection was higher in urban (MOI = 1.5–2) compared to rural areas (MOI = 1) (p = 0.003). The level of genetic diversity was similar in all areas (He = 0.66–0.76, p = 0.32) though genetic differentiation between areas was substantial (PHI_PT = 0.17, p<0.0001). Principal coordinate analysis showed a marked differentiation between parasites from urban and rural areas. Linkage disequilibrium was detected in all the areas (IAs = 0.08–0.49, for all p<0.0001). Gene flow among the areas was stablished through Bayesian analysis of migration models. Recent bottleneck events were detected in 4 areas and a recent parasite expansion in one of the isolated areas. In total, 87 unique haplotypes grouped in 2 or 3 genetic clusters described a sub-structured parasite population.

Conclusion/Significance

Our study shows a sub-structured parasite population with clonal propagation, with most of its components recently affected by bottleneck events. Iquitos city is the main source of parasite spreading for all the peripheral study areas. The routes of transmission and gene flow and the reduction of the parasite population described are important from the public health perspective as well for the formulation of future control policies.     

Primates of the Río Curaray,Northern Peruvian Amazon

We conducted a short survey of primates along the Río Curaray in the northern Peruvian Amazon, emphazing rare, threatened or little known species. Contrary to Thorington, (Thorington, R. W., Jr., 1988, Am. J. Primatol. 15:367–371), we found no evidence for sympatry between Saguinus tripartitus and Saguinus fuscicollis, with the former being restricted to the north bank and the latter to the south bank of the Río Curaray. The Curaray also separates two species of Pithecia. The height above ground at which species were encountered increased with body size, providing evidence for vertical stratification within the primate community. The Curaray area still has rich primate diversity compared to other areas in the northern Peruvian Amazon, even though larger species, such as the spider monkeys, are hunted.     

Socioeconomic dimensions,migration, and deforestation: An integrated model of territorial organization for the Brazilian Amazon

The territory organization of the Brazilian Amazon, understood as a socioeconomic network of municipalities, reflects the diversity of human settlements and their potentials for environmental changes, especially deforestation. This paper characterizes the urban network in the Brazilian Amazon through a model that integrates the levels of socioeconomic organization of municipalities and their interrelationships, as determined through migratory movements. The model of territorial organization combines five components: (i) the hierarchy of central places (poles) established by the concentration of urban specialized services, (ii) the geographical distance between central poles and other centers, (iii) the poles’ populations, (iv) the migratory movements among them, and (v) a socioeconomic dimension index. These components are combined into a gravitational model to produce measures and maps of the socioeconomic municipality network of the Brazilian Amazon. As a result, out of 792 municipalities in the Brazilian Amazon, 9 were classified as macro-poles, 29 were classified as meso-poles and 48 as micro-poles. The areas of influence of these poles were determined according to the three hierarchy levels. The Amazon region network comprises a nested spatial pattern of municipalities not constrained by the state boundaries. Socioeconomic space and population movements influence the mobility of the deforestation frontier. This analysis provides insights to predict deforestation as well as to guide formulation of sustainable development policies suitable for each region's specificity.     

Distribution of Agrobiodiversity in Home Gardens along the Corrientes River,Peruvian Amazon

Distribution of Agrobiodiversity in Home Gardens along the Corrientes River, Peruvian Amazon. This paper examines crop species diversity in home gardens of traditional communities along a remote tributary in northeastern Peru. A large-scale survey was conducted of 300 gardens in 15 villages along a 150 km reach of the Corrientes River. Study villages vary notably in community size, ethnicity of residents (Achuar, Urarina, mestizo), and proximity to the regional town (Trompeteros) as well as to oil wells. Gardens were inventoried and interviews conducted with garden tenders to provide data on socioeconomic characteristics of the household and contextual conditions. Multiple regression analyses identified the determinants of species diversity. Results indicate high crop diversity—the highest yet reported for sites in the Amazon basin—particularly among the Achuar people. Garden species diversity is greatest in larger villages and, surprisingly, in those villages located nearer to the oil company. Within villages, households with larger land holdings (and gardens), more in-house labor, and garden tenders who are older and female tend to have more diverse gardens. A small number of households (15/300) were found to hold exceptional diversity, often older and land-wealthier households located on the outskirts of villages. These farmers held, on average, three times the number of species as a typical village garden and 60% of all species encountered in the study.     

Strategies for genetic conservation of trees in the Peruvian Amazon

Forestry practices and high rates of land clearance for agriculture are causing genetic erosion of valuable tree species in the Peruvian Amazon, thereby endangering the economic sustainability of rural communities and limiting Peru's opportunities for the development of new timber and non-timber forest products. The potential utility and limitations of six low-input interventions to help forestall further genetic erosion in the region are discussed, with a focus on local community involvement. Improved agroforestry systems may help reduce deforestation by increasing farm productivity, although methods to increase the currently low adoption rate of these technologies need to be developed. Use of strategic tree domestication techniques can also improve farm productivity and prevent inadvertent genetic drift and inbreeding associated with traditional domestication practices, although to have a major impact, current programs need to be extended across the region. Woodlot forestry could supplant selective extraction of timber and offers an attractive opportunity for poverty alleviation if appropriate credit and land tenure policies can be developed. However, it may also result in increased deforestation if activities on public land cannot be controlled. The implementation of improved seed collection systems and simple seed transfer guidelines would help to reduce the collection of seed of poor quality and low genetic diversity, and avoid maladapted plantings, although such programs are difficult to monitor and seed costs may increase. Strategic identification and design of in situ conservation areas would help to ensure the viability of conserved populations, but requires the forfeiture of significant revenue from timber concessions.     

Pteridophyte species diversity in the central Peruvian Amazon: Importance of edaphic specialization

Sixty-one species of pteridophytes were found growing in a two-hectare study area that contained two major soil types. Approximately one-third of that species richness was due to the presence of edaphic variation, because 19 species were only found on the sandy loam soil and 24 were restricted to the clay soil. In the Amazon basin, within a particular climatic zone, diversity of soil type and topographic position can result in a habitat mosaic where both edaphic specialists and generalists can be found growing in one area. Sesentaiún especies de pteridófitos se hallaron en el área de estudio de dos hectáreas, el cual contenía dos tipos resaltantes de suelos. Aproximadamente un tercio de la riqueza de especies se debió a la diferencia edáfica, así 19 de ellas se hallaron en el suelo arenoso y 24 sólo en el arcilloso. En la Amazonía, dentro de una determinada zona climática, la diversidad en tipos de suelos y la posición topográfica pueden dar lugar a un habitat en mosaico, donde tanto especialistas edáficos como generalistas pueden crecer en una sola área.     

The ghosts of forests past and future: deforestation and botanical sampling in the Brazilian Amazon

The remarkable biodiversity of the Brazilian Amazon is poorly documented and threatened by deforestation. When undocumented areas become deforested, in addition to losing the fauna and flora, we lose the opportunity to know which unique species had occupied a habitat. Here we quantify such knowledge loss by calculating how much of the Brazilian Amazon has been deforested and will likely be deforested until 2050 without having its tree flora sufficiently documented. To this end, we analysed 399 147 digital specimens of nearly 6000 tree species in relation to official deforestation statistics and future deforestation scenarios. We find that by 2017, 30% of all the localities where tree specimens had been collected were mostly deforested. Some 300 000 km² (12%; 485 25 × 25 km grid cells) of the Brazilian Amazon had been deforested by 2017, without having a single tree specimen recorded. An additional 250 000–900 000 km² of severely under-collected rainforest will likely become deforested by 2050. If future tree sampling is to cover this area, sampling effort has to increase two- to six-fold. Nearly 255 000 km² or 7% of rainforest in the Brazilian Amazon is easily accessible but does yet but remain under-collected. Our study highlights how progressing deforestation increases the risk of losing undocumented species of a hyper-diverse tree flora.     

The use, construction, and importance of canoes among the Maijuna of the Peruvian Amazon

Canoe construction was studied in a Maijuna community to better understand the role and significance of canoes in the life and subsistence strategies of an Amazonian group. In this community the types of canoes constructed and used by the Maijuna have changed considerably over the past 20 years. Twenty-seven species were identified as being specifically employed by the Maijuna to construct the type of dugout canoe currently being made in the community. The scarcity of preferred species used for canoe hulls directly affects the trees chosen for construction and may have been a contributing factor behind the complete switch from making the traditional type of dugout canoe.     

Market Incorporation, Agricultural Change, and Sustainability Among the Machiguenga Indians of the Peruvian Amazon

By marshaling empirical data from five Machiguenga communities studied over 20 years, this paper disputes two common assumptions about the behavior of indigenous peoples in the face of increasing commercialization. First, many Amazonian researchers suggest that the social and ecological deterioration confronting native populations results from externally-imposed political, legal and market structures that compel local groups to pursue short-term, unstable economic strategies. Second, these structural explanations are combined with the increasing recognition that indigenous peoples possess a substantial agroecological knowledge to suggest that, if indigenous people receive control of adequate land and resources, they will implement their traditional knowledge in conservative resource management practices. In contrast to these assumptions, this analysis shows that the Machiguenga are not compelled by external forces (such as land tenure, migration policies or economic trends), but instead are active enthusiastic participants seeking to engage the market in order to acquire western goods. Further, despite highly adaptive traditional subsistence patterns and a vast agroecological knowledge, households and communities facing increasing degrees of market integration are progressively altering their traditional cropping strategies, planting practices, labor allocation and land use patterns toward a greater emphasis on commodity crop production and domesticated animal breeding. This increasing concentration on income generating activities subverts the environmentally-friendly nature of traditional productive practices and creates a socially, economically, and ecologically unsustainable system.     

Indigenous diversity of Cassava: Generation, maintenance, use and loss among the Amuesha, Peruvian upper Amazon

For cassava (Manihot esculenta Euphorbiaceae), results from field collection, semistructured interviews, phenetic and cluster analyses, and Global Information Systems (G1S) indicate that cassava phenotypes vary with elevation and topography, but less with soils or pests and diseases. Amuesha women with a sense of tradition maintain many cassava varieties along with associated myths, songs, names and indigenous production. The shaman plays a key role in breeding new and maintaining traditional cassava germplasm, while the rest of the tribe nurtures cassava germplasm dynamics through collecting, trading, stealing, maintaining favored cassava varieties, and purging the less desirable. The future of cassava diversity is of concern to some Amuesha as production and market interests surmount more traditional attention to variety.     

Patterns of Geographic Expansion of Aedes aegypti in the Peruvian Amazon

Background and Objectives

In the Peruvian Amazon, the dengue vector Aedes aegypti is abundant in large urban centers such as Iquitos. In recent years, it has also been found in a number of neighboring rural communities with similar climatic and socioeconomic conditions. To better understand Ae. aegypti spread, we compared characteristics of communities, houses, and containers in infested and uninfested communities.

Methods

We conducted pupal-demographic surveys and deployed ovitraps in 34 communities surrounding the city of Iquitos. Communities surveyed were located along two transects: the Amazon River and a 95km highway. We calculated entomological indices, mapped Ae. aegypti presence, and developed univariable and multivariable logistic regression models to predict Ae. aegypti presence at the community, household, or container level.

Results

Large communities closer to Iquitos were more likely to be infested with Ae. aegypti. Within infested communities, houses with Ae. aegypti had more passively-filled containers and were more often infested with other mosquito genera than houses without Ae. aegypti. For containers, large water tanks/drums and containers with solar exposure were more likely to be infested with Ae. aegypti. Maps of Ae. aegypti presence revealed a linear pattern of infestation along the highway, and a scattered pattern along the Amazon River. We also identified the geographical limit of Ae. aegypti expansion along the highway at 19.3 km south of Iquitos.

Conclusion

In the Peruvian Amazon, Ae. aegypti geographic spread is driven by human transportation networks along rivers and highways. Our results suggest that urban development and oviposition site availability drive Ae. aegypti colonization along roads. Along rivers, boat traffic is likely to drive long-distance dispersal via unintentional transport of mosquitoes on boats.