Peruvian Amazon Research Articles

Resilience of Aboveground Biomass of Secondary Forests Following the Abandonment of Gold Mining Activity in the Southeastern Peruvian Amazon

Amazon rainforests are critical for providing a wide range of ecosystem services. In the Southeastern Peruvian Amazon; however, goldmining activities are causing severe soil degradation and forest loss. We analyzed aboveground biomass (AGB), forest structure, and species diversity recovery during secondary succession in 179 forest plots. Our study provides the first field-based quantification of AGB recovery following the abandonment by two types of goldmining (heavy machinery and suction pumping) in Madre de Dios (Peru). We found that successional secondary forests in areas subjected to suction pumping were more resilient than those in areas subjected to heavy machinery. After 20 years, mean AGB in suction pumping mining areas had reached 56% of reference forest AGB, while in areas of heavy machinery mining it was only 18%. Mining type, stand age, and distance from the forest edge had a significant effect on AGB. The influence of the distance from the forest edge on AGB varies according to mining type because the effects of species diversity on AGB are mediated by the distance from the forest edge. Our results clearly showed the dynamics of AGB recovery across a secondary succession after goldmining, and the contrasting responses of AGB between the two mining types. Our study disentangles the importance of key factors in forest recovery after mining and improves understanding of the resilience of biomass accumulation in these highly degraded ecosystems.

Helicobacter pylori exposure among the Awajún of the Peruvian Amazon: Prevalence and environmental, social, and biological associations.

Helicobacter pylori (H. pylori)-a gastric bacteria affecting almost 50% of the global population and leading to ulcers and cancer in severe cases-is a growing health concern among Indigenous populations who report a high burden of reported poor general health and gastrointestinal distress. We test hypothesized associations between H. pylori exposure patterns and environmental, social, and biological conditions among a sample of 212 Indigenous Awajún adults (112 males, 100 females, ages 18-65 years) living in the northern Peruvian Amazon. Dried blood spots were analyzed for H. pylori-specific IgG using a recently developed enzyme-linked immunosorbent assay. Resulting seropositivity rates and antibody concentrations, proxying past exposures to H. pylori were analyzed in relation to relevant environmental (toilet type, floor material, reported water quality), social (household size and education level), and biological (age, sex, BMI, blood pressure, immune and metabolic biomarkers) factors using multivariable regression analyses. We found near ubiquitous seropositivity for H. pylori exposure in our sample (99.1% seropositive). In the regression analyses, elevations in H. pylori antibody concentrations were significantly higher among males compared to females (β = 0.36, p = 0.01). No associations were found with any other factors. Anthropological research in the study communities suggests that the male bias in elevations of H. pylori antibody concentrations is related to cultural and biological factors. Future research is needed to further unravel these biocultural dynamics and determine whether elevations in H. pylori antibody concentrations have clinical relevance for gastrointestinal health outcomes in this population.

Diet choices determine mercury exposure risks for people living in gold mining regions of Peru

Abstract Artisanal and small-scale gold mining (ASGM) is the largest global anthropogenic mercury (Hg) source and is widespread in the Peruvian Amazon. Consuming Hg-laden foods exposes people to this potent neurotoxin. While numerous studies have examined fish Hg content near ASGM, Hg accumulation in other commonly consumed animal- and plant-based foods from terrestrial environments is often overlooked. In this study, we aim to address understudied dietary Hg exposures. 
To understand Hg exposure from food staples in the Peruvian Amazon, we measured total and methyl Hg in local crops, fish, chicken meat, chicken feathers, and eggs from ASGM-impacted and upstream (reference) communities. Diet surveys were used to estimate probable weekly Hg intake from each food. Fish and chicken stable carbon and nitrogen isotope signatures were analyzed to evaluate trophic magnification. 
Though few crops exceeded food safety recommendations, rice methyl Hg proportions were high (84%). Trophic level was an expected key predictor of fish Hg content. 81% (17 of 21) of local carnivorous fish exceeded WHO and USEPA recommendations. Compared to upstream communities, mining-impacted communities demonstrated elevated total Hg in crops (1.55 (IQR: 0.60-3.03) μg/kg upstream versus 3.38 (IQR: 1.62-11.58) in mining areas), chicken meats (2.69 (IQR: BDL-9.96) μg/kg versus 19.68 (IQR: 6.33-48.1)), and feathers (91.20 (IQR: 39.19-216.13) μg/kg versus 329.99 (IQR: 173.22-464.99)). Chicken meats from mining areas exhibited over double the methyl Hg concentrations of those upstream. Methyl Hg fractions in chicken muscle tissue averaged 93%. Egg whites and livers exceeded Hg recommendations most frequently. Proximity to mining, but not trophic position, was a predictor of chicken Hg content. 
Our results demonstrate that terrestrial and aquatic foods can accumulate Hg from mining activity, introducing additional human Hg exposure routes. However, locally sourced carnivorous fish was the largest contributor to an estimated three-fold exceedance of the provisional tolerable weekly Hg intake.

Implementation of new technologies designed to improve cervical cancer screening and completion of care in low-resource settings: a case study from the Proyecto Precancer

BackgroundThis case study details the experience of the Proyecto Precancer in applying the Integrative Systems Praxis for Implementation Research (INSPIRE) methodology to guide the co-development, planning, implementation, adoption, and sustainment of new technologies and screening practices in a cervical cancer screening and management (CCSM) program in the Peruvian Amazon. We briefly describe the theoretical grounding of the INSPIRE framework, the phases of the INSPIRE process, the activities within each phase, and the RE-AIM outcomes used to evaluate program outcomes.MethodsProyecto Precancer iteratively engaged over 90 stakeholders in the Micro Red Iquitos Sur (MRIS) health network in the Amazonian region of Loreto, Perú, through the INSPIRE phases. INSPIRE is an integrative research methodology grounded in systems thinking, participatory action research, and implementation science frameworks such as the Consolidated Framework for Implementation Research. An interrupted time-series design with a mixed-methods RE-AIM (Reach, Effectiveness, Adoption, Implementation, and Maintenance) evaluation framework was used to examine the adoption of human papillomavirus (HPV) testing (including self-sampling), with direct treatment after visual inspection with portable thermal ablation, at the primary level.ResultsThis approach, blending participatory action research, implementation science, and systems-thinking, led to rapid adoption and successful implementation of the new cervical cancer screening and management program within 6 months, using an HPV-based screen-and-treat strategy across 17 health facilities in one of the largest public health networks of the Peruvian Amazon. Monitoring and evaluation data revealed that, within 6 months, the MRIS had surpassed their monthly screening goals, tripling their original screening rate, with approximately 70% of HPV-positive women reaching a completion of care endpoint, compared with around 30% prior to the new CCSM strategy.ConclusionsProyecto Precancer facilitated the adoption and sustainment of HPV testing with subsequent treatment of HPV-positive women (after visual inspection) using portable thermal ablation at the primary level. This was accompanied by the de-implementation of existing visual inspection-based screening strategies and colposcopy for routine precancer triage at the hospital level. This case study highlights how implementation science approaches were used to guide the sustained adoption of a new screen-and-treat strategy in the Peruvian Amazon, while facilitating de-implementation of older screening practices.

Hunting and wildmeat trade: Case study in three amazonian indigenous communities in Ucayali, Peru

Little is known about how bushmeat markets operate in the Peruvian Amazon and the influence they have on levels of extraction for food and commercial purposes. The research analyzes how the price of wildmeat is related to the intensity of hunting in native communities near the city of Pucallpa. The study confirms that the extraction, trade and use of bushmeat in these native communities are related to the trade of the resource in the city. The amount of meat shared, meat sold, and the average price influence the total amount of meat hunted. If prices vary, the quantities of meat hunted for sale also vary. It is recommended to promote local self-regulation, through which the communities organize themselves to guarantee the permanence of healthy populations of wildlife and benefit without harming the ecosystem. It is suggested to promote the legal sale of bushmeat in formal markets of Pucallpa for managed species so that it can be subject to greater control, allowing prices to achieve a sustainable level of equilibrium in the extraction and sale of bushmeat.

Soil carbon stock potential in pastoral and silvopastoral systems in the Peruvian Amazon

AbstractResearch evaluating the impact of silvopastoral systems on physical and biological properties of Amazonian soils is scarce. Thus, this study aimed to compare the soil carbon storage potential and physical and chemical soil properties of silvopastoral systems (SPS) and conventional pastoral systems (CPS) in the San Martin region of Peru. Using the Walkley and Black method, we analyzed soil organic matter at two different depths (0–15 cm and 15–30 cm). In addition, bulk density, soil moisture, total porosity, and mechanical resistance were measured in both systems. The highest (P < 0.05) carbon stocks were reported at 0–15 cm of depth with values of 31.4 Mg ha−1 and 34.4 Mg ha−1 for CPS and SPS, respectively. At 15–30 cm depth, the total carbon stock was higher for SPS, with 29.12 Mg ha−1, than for CPS, which had 26.4 Mg ha−1. Despite the absence of statistically significant differences, soil carbon stocks were higher in SPS. No significant differences in soil moisture were found between systems, although soil moisture was slightly greater in SPS than CPS (28 and 25%, respectively). The CPS had 59% of the total porosity, which was higher than the SPS. Mechanical resistance was lower in SPS (2.15 kg/cm2) than in CPS (2.33 kg/cm2) at 10 cm of depth. These results indicated that the SPS has the potential to store more carbon and improve physical and chemical traits in the soil than the CPS.

Slow environmental justice: the Cuninico oil spill and the legal struggle against oil pollution in Peruvian Amazonia

ABSTRACT This paper analyzes a case of environmental activism after one of the largest oil spills in Peruvian Amazonia, the 2014 Cuninico oil spill. A relatively more independent judiciary, environmental legislation, and weak though autonomous regulatory agencies led to a shift in institutional opportunity structure over the previous 20 years. The embryonic environmental state produced evidence of environmental harm and sanctioned state-owned oil enterprise Petroperú. However, that was not enough to produce timely measures to protect the affected communities. Indigenous peoples affected by the spill worked with human rights lawyers and civil society coalitions to bring the company to court. Almost a decade of high court activism has meant a burdensome process of ‘lawfare’ with important legal triumphs for plaintiffs. In 2020, a historic ruling mandated financial compensation for affected communities. Despite these triumphs, the long wait for the restitution of justice hints at an uncertain future.

Plant species richness, not hygrothermal stress, is the main predictor of gall‐inducing insect richness in Peruvian Amazon forests

AbstractPatterns of gall‐inducing insect diversity tend to be influenced by both habitat‐related and plant‐related characteristics. We investigated the distribution patterns of galling insects in four vegetation types (terra firme forest, white‐sand dry forest, white‐sand wet forest and palm swamp forest) of the Peruvian Amazon to test if the insect gall diversity (1) differs among different types of vegetation and (2) depends on host plant richness. In total, we found 11,579 galls belonging to 249 insect gall morphotypes, distributed across 30 botanical families and 75 plant species. Among host plant families, Fabaceae showed the greatest richness of insect gall morphotypes. We found that galling species richness was lower in palm swamp forest than in white‐sand forests, which can be explained by the lower richness of plants in this type of vegetation. However, we found no evidence of greater richness in xeric habitats (e.g., white‐sand dry forest) than in more mesic vegetation (terra firme forest), contradicting the hypothesis of hygrothermal stress. We also found that plant species richness was positively influenced with the richness and abundance of galling species, regardless of vegetation type. Galling insect species composition differed significantly between vegetation types, similarly to the floristic composition. Our findings show that the diversity of galling insects in the tropical rainforests of Peruvian Amazon are mainly influenced by host plant composition and host plant richness.Abstract in Spanish is available with online material.

Hydrogeomorphic Characterization of the Huallaga River for the Peruvian Amazon Waterway

Hydrogeomorphic Characterization of the Huallaga River for the Peruvian Amazon Waterway

SUSTAINABLE MODULAR PROTOTYPE WITH BAMBOO FOR COMMUNITY CENTERS

This contribution presents the results of research carried out in two areas of the Peruvian Amazon within the framework of two community projects for technology transfer and capacity development in construction with bamboo, with the objective of designing and building a modular prototype with bamboo for 1/1 scale with the function of a community center, capable of incorporating sustainable strategies, replicability and adaptability, as an architectural alternative to the deterioration of the Amazonian natural and cultural habitat. The methodology contemplates two phases of experimentation, the first of design and construction of the Model Prototype in the Southwest Amazon (Pilcopata), studying the local context, the bamboo species, the participatory construction process, to formulate the modular proposal with the function of a Center Tourist Community; the second validation of the Prototype, identifying the bamboo species and adding a module in the design format for use in the Communal Transformation Center in the Central Amazon (Native Community of Pampa Michi), both executed with the local population. Among the results, the efficiency, practicality and flexibility of the design and construction stand out, and the verification of sustainable strategies, with the use of carbon neutral materials such as bamboo, the revaluation of traditional knowledge with palm leaves and the replicability in similar conditions with models of participatory learning, which validate the Prototype. In a third phase, the construction processes are systematized, being part of the Manual for the construction of light structures with bamboo in Peru.

Possible Spreading of SARS-CoV-2 from Humans to Captive Non-Human Primates in the Peruvian Amazon.

Human-to-animal transmission events of SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) have been reported in both domestic and wild species worldwide. Despite the high rates of contagion and mortality during the COVID-19 (Coronavirus Diseases 2019) pandemic in Peru, no instances of natural virus infection have been documented in wild animals, particularly in the Amazonian regions where human-wildlife interactions are prevalent. In this study, we conducted a surveillance investigation using viral RNA sequencing of fecal samples collected from 76 captive and semi-captive non-human primates (NHPs) in the Loreto, Ucayali, and Madre de Dios regions between August 2022 and February 2023. We detected a segment of the RNA-dependent RNA polymerase (RdRp) gene of SARS-CoV-2 by metagenomic sequencing in a pooled fecal sample from captive white-fronted capuchins (Cebus unicolor) at a rescue center in Bello Horizonte, Ucayali. Phylogenetic analysis further confirmed that the retrieved partial sequence of the RdRp gene matched the SARS-CoV-2 genome. This study represents the first documented instance of molecular SARS-CoV-2 detection in NHPs in the Peruvian Amazon, underscoring the adverse impact of anthropic activities on the human-NHP interface and emphasizing the importance of ongoing surveillance for early detection and prediction of future emergence of new SARS-CoV-2 variants in animals.

Elevated mercury exposure in bird communities inhabiting Artisanal and Small-Scale Gold Mining landscapes of the southeastern Peruvian Amazon.

Artisanal and Small-Scale Gold Mining (ASGM) represents a significant source of anthropogenic mercury emissions to the environment, with potentially severe implications for avian biodiversity. In the Madre de Dios department of the southern Peruvian Amazon, ASGM activities have created landscapes marred by deforestation and post-mining water bodies (mining ponds) with notable methylation potential. While data on Hg contamination in terrestrial wildlife remains limited, this study measures Hg exposure in several terrestrial bird species as bioindicators. Total Hg (THg) levels in feathers from birds near water bodies, including mining ponds associated with ASGM areas and oxbow lakes, were analyzed. Our results showed significantly higher Hg concentrations in birds from ASGM sites with mean ± SD of 3.14 ± 7.97 µg/g (range: 0.27 to 72.75 µg/g, n = 312) compared to control sites with a mean of 0.47 ± 0.42 µg/g (range: 0.04 to 1.89 µg/g, n = 52). Factors such as trophic guilds, ASGM presence, and water body area significantly influenced feather Hg concentrations. Notably, piscivorous birds exhibited the highest Hg concentration (31.03 ± 25.25 µg/g, n = 12) exceeding known concentrations that affect reproductive success, where one measurement of Chloroceryle americana (Green kingfisher; 72.7 µg/g) is among the highest ever reported in South America. This research quantifies Hg exposure in avian communities in Amazonian regions affected by ASGM, highlighting potential risks to regional bird populations.

Assessment of Information Literacy Competences in Peruvian University Students: An Exploratory Study

The objective was to evaluate the perception of the informational literacy competences of the university students of the Peruvian Amazon. The investigation was developed under a quantitative approach, the design was non-experimental and cross-sectional descriptive type. The sample was made up of 707 students to whom the Informational Literacy Competences Questionnaire was given, an instrument with an adequate level of content validity and reliability. According to the results, the level of development of the informational literacy competencies of 37.5% of students was low, 35% was medium, and 27.5% was high. Likewise, the dimensions of information retrieval, information assessment and information processing were also valued at a low level. However, the information communication dimension of information was valued at a medium level. On the other hand, it was found that the level of informational literacy competences was significantly associated with the year of study in which the students were (p<0.05). It was concluded that the level of development of the informational literacy competencies that characterized the students was low.

Correction: A multiple linear regression model for the prediction of summer rainfall in the northwestern Peruvian Amazon using large-scale indices

Correction: A multiple linear regression model for the prediction of summer rainfall in the northwestern Peruvian Amazon using large-scale indices

Malaria seroepidemiology in very low transmission settings in the Peruvian Amazon

Despite progress towards malaria reduction in Peru, measuring exposure in low transmission areas is crucial for achieving elimination. This study focuses on two very low transmission areas in Loreto (Peruvian Amazon) and aims to determine the relationship between malaria exposure and proximity to health facilities. Individual data was collected from 38 villages in Indiana and Belen, including geo-referenced households and blood samples for microscopy, PCR and serological analysis. A segmented linear regression model identified significant changes in seropositivity trends among different age groups. Local Getis-Ord Gi* statistic revealed clusters of households with high (hotspots) or low (coldspots) seropositivity rates. Findings from 4000 individuals showed a seropositivity level of 2.5% (95%CI: 2.0%-3.0%) for P. falciparum and 7.8% (95%CI: 7.0%-8.7%) for P. vivax, indicating recent or historical exposure. The segmented regression showed exposure reductions in the 40–50 age group (β1 = 0.043, p = 0.003) for P. vivax and the 50–60 age group (β1 = 0.005, p = 0.010) for P. falciparum. Long and extreme distance villages from Regional Hospital of Loreto exhibited higher malaria exposure compared to proximate and medium distance villages (p < 0.001). This study showed the seropositivity of malaria in two very low transmission areas and confirmed the spatial pattern of hotspots as villages become more distant.

Disentangling shade effects for cacao pest and disease regulation in the Peruvian Amazonia

Disentangling shade effects for cacao pest and disease regulation in the Peruvian Amazonia

Characterization and phylogenetic analysis of the complete plastid genome of Theobroma bicolor (Malvaceae) from Peru

Theobroma bicolor Bonpl. 1806 is distributed in the Neotropics from southern Mexico to the Peruvian and Brazilian Amazon. High-throughput sequencing of T. bicolor from Peru (KUELAP2926) resulted in the assembly of its complete plastid genome (GenBank accession number OQ557154). The chloroplast genome of T. bicolor is A + T-rich (62.97%), having 160,317 bp in size and containing 130 genes; including a pair of inverted repeat regions (IRs) of 25,462 bp separated by a large single copy region (LSC) of 89,221 bp and a small single copy region (SSC) of 20,172 bp. This plastid genome is similar in length, content, and organization to other members of the genus Theobroma. Phylogenetic analyses of T. bicolor support its sistership to the clade comprising T. cacao and T. grandiflorum. This study may contribute valuable information to the phylogenetic relationships within the genus Theobroma.

Training with a psychosocial health neurolearning approach in Peruvian professionals with health insurance: Experimental study.

Psychosocial risk factors as determinants of health at work can affect both the physical and psychological well-being of the worker. Training systems that include cognitive-preventive content work best when knowledge construction is based on neurolearning. The purpose of this study was to compare the degree of content processing with the insertion of deterrent (group A) versus persuasive sentences (group B) as an effect of a training with a neurolearning approach to psychosocial health in the work of a group of professionals with health insurance in the Peruvian Amazon. Experimental design with pre-/post-test, including two experimental groups plus a control group, n = 48 subjects in total and 16 per group, aged 22-36 years. The training took place between December 2018 and January 2019 with a duration of 18 hours spaced over six weeks. A register previously validated by five experts was used for data collection. The distribution of data in the groups was adequate in both pre-test and post-test, except in post-test in group "B" (p = 0.002). In the control group, the results of content processing in both pre-test and post-test remained similar (p = 0.667). The processing of psychosocial occupational health content in the post-test was significantly different between the intervention and control groups (p = 0.001), distinguishing the processing of content with the insertion of deterrent phrases. The results indicate that training with a neurolearning approach can improve the processing of content with the insertion of deterrent phrases for compliance with regulations aimed at promoting psychosocial health at work.

Soil characteristics and allometric models for biometric characteristics and nutrient amounts for high yielding “Bolaina” (Guazuma crinita) trees

The Peruvian amazon is very diverse in native forestry species, the Guazuma crinita “Bolaina” being one of the most planted species in the country; however, little or no information about soil requirements and nutrient demands is known. The objective of this work was to assess the general conditions of soil fertility, biomass and macro- and micronutrient amounts in high-productivity Guazuma crinita plantations. Fields of high yielding Bolaina of different ages (1–10 years) were sampled in two regions. Soil and plant samples were collected in each field and biometric measurements of fresh weight, diameter at breast height and height were performed. For soil and plant analysis, both macro- (N, P, K, Ca, Mg, S) and micronutrients (B, Cu, Fe, Mn, Zn) were determined. Finally, allometric equations were constructed for biometric and nutrient amounts. This study is the first to assess and model macro- and micronutrient amounts in the productive cycle in this species, which grows in fertile soils. In the case of biometric equations, the logarithmic and logistic models performed better. For nutrient amounts, this species followed a pattern of Ca > N > K > P > S > Mg for macronutrients and Fe > B > Mn > Zn > Cu for micronutrients. The best prediction models for nutrients were the square root and logistic models.

Two new species of dactylogyrids (Monogenea: Dactylogyridae) infecting the gill filaments of fishes in the southern Peruvian Amazon.

Two new dactylogyrid species were found infecting the gill filaments of two freshwater fishes collected in the Amazon River basin around Madre de Dios, Peru, namely, Demidospermus wilveri n. sp. from Loricaria sp. (Siluriformes: Loricariidae), and Notozothecium agusti n. sp. from Brycon amazonicus (Spix & Agassiz) (Characiformes: Bryconidae). Demidospermus wilveri n. sp. is characterized by having the following combination of characteristics: (1) a male copulatory organ (MCO) with 1½ rings and a spoon-shaped distal end, (2) an accessory piece with expanded distal end, (3) dorsal and ventral bars with broadly V-shaped and expanded ends, and (4) hooks similar in size. Notozothecium agusti n. sp. differs from its ten congeners by the following combination of characteristics: (1) a coiled MCO with 1½ rings and a sinuous accessory piece with kidney-shaped distal end, (2) an rod-shaped and straight dorsal bar, (3) and anchors with robust superficial roots. Demidospermus wilveri n. sp. represents the thirty-second species in the genus, the eighth from Peru and the fifth parasitising a loricariid catfish from the Peruvian Amazon. Notozothecium agusti n. sp. is the second species of the genus described in Peru and the first species infecting a bryconid host.