Vegetation types of the upper Madeira River in Rondônia,Brazil

We characterize the vegetation types of the upper basin of the Madeira River in the Brazilan state of Rondônia, a biodiverse region with elevated rates of habitat loss. Vegetation and environmental parameters were recorded from 37 observation points distributed along and near a 160 km stretch of the Madeira River and representing the range of regional environments. Analysis of structure and floristic variables, as well as associated edaphic attributes and water table fluctuation, permitted recognition of five main vegetation types and seven subtypes. Open Ombrophilous Forest was the most frequently encountered vegetation type and occurred on well-drained, nutrient-poor soils, whereas Dense Ombrophilous Forest was seldom recorded. Alluvial Ombrophilous Forests (várzea) were found along a narrow strip of land along the banks of the Madeira River on the most fertile soils in the study area. Semideciduous Forests were found on small areas of rocky outcrops with shallow soils and reduced water availability during the dry season. Campinaranas, which range from open savanna physiognomies to closed canopy forests, were found to be a key environment in the lowlands south of the Madeira River on silty hydromorphic soils, where they harbor a peculiar flora tolerant of flooding during the rainy season. Our classification of the main vegetation types in the upper Madeira River illuminates a high degree of floristic and environmental heterogeneity in a highly threatened region. Our results will be useful for designing conservation strategies aimed at protecting the full range of floristic diversity present in the region.     

Effects of pasture introduction on soil CO2 emissions during the dry season in the state of Rondônia,Brazil

Soil CO₂ evolution rates, soil temperatures and moisture were measured during the dry season in two forest-to-pasture chronosequences in Rondônia, Brazil. The study included pastures ranging from 3 to 80 years-old. Mean dry-season CO₂ evolution from the forest in chronosequence 1, 88.8 mg CO₂-C m^–2h^–1 was lower than from the pastures which ranged from 111 to 158 mg CO₂-C m^–2h^–1. We found that temperature was not a good predictor of CO₂ emissions from pasture but that there was a significant relationship (r = 0.72,p < 0.05) between soil moisture and pasture emissions. The ¹³C of the soil CO₂ emissions also was measured on chronosequence I; ¹³C of the CO₂ emitted from the C3 forest was –29.43%. Pasture¹³CO₂ values increased from –17.91%. in the 3 year-old pasture to –12.86% in the 80 year-old, reflecting the increasing C₄ inputs with pasture age. Even in the youngest (3 year-old) pasture, 70 percent of the CO₂ evolved originated from C₄ pasture-derived carbon.     

An autochthonous case of Echinococcus vogeli Rausch & Bernstein, 1972 polycystic echinococcosis in the state of Rondônia, Brazil

The present case report refers to a patient from the State of Rond?nia, North region of Brazil, attended with clinical suspicion of hepatic echinococcosis. Examination by imaging (ultrasonography and computerized tomography) revealed a conglomerate of cystic lesions, with mobile contents within the cyst. The serology (immunoblot) for Echinococcus sp. was positive (21 and 31 kDa bands). This case is the first reported in Rond?nia, suggesting the need to investigate the polycystic echinococcosis in individuals with hepatic cysts from areas of tropical forest and hunting habits where wild life was present as wild dogs, cats and rodents, particularly Agouti paca (paca) and Dasyprocta aguti (agouti).     

Population structure of the malaria vector Anopheles darlingi in Rondônia, Brazilian Amazon, based on mitochondrial DNA

Anopheles darlingi is the most important Brazilian malaria vector, with a widespread distribution in the Amazon forest. Effective strategies for vector control could be better developed through knowledge of its genetic structure and gene flow among populations, to assess the vector diversity and competence in transmitting Plasmodium. The aim of this study was to assess the genetic diversity of An. darlingi collected at four locations in Porto Velho, by sequencing a fragment of the ND4 mitochondrial gene. From 218 individual mosquitoes, we obtained 20 different haplotypes with a diversity index of 0.756, equivalent to that found in other neotropical anophelines. The analysis did not demonstrate significant population structure. However, haplotype diversity within some populations seems to be over-represented, suggesting the presence of sub-populations, but the presence of highly represented haplotypes complicates this analysis. There was no clear correlation among genetic and geographical distance and there were differences in relation to seasonality, which is important for malarial epidemiology.     

Titi monkeys (Callicebus spp., Atelidae: Platyrrhini) in the Brazilian state of Rondônia

Five species of titi monkey (Callicebus brunneus, Callicebus caligatus Callicebus cinerascens, Callicebus donacophilus, andCallicebus moloch) were recorded in surveys of primate populations at 26 sites throughout the Brazilian state of Rondônia. The distribution of the two species,C. cinerascens andC. donacophilus (recorded in the state for the first time), appeared to be related to that of non-forest ecosystems, the former in thecerrado woodlands, and the latter in gallery forests of the Guaporé grasslands. The results of the surveys also indicate thatC. brunneus has a more restricted distribution in southern Rondônia than was previously thought, whereasC. moloch is more widespread. However, the ecological factors that determine species distribution in the south of the state remain unclear on the basis of the available data. All species were observed in small social groups of no more than five individuals, which are typical of the genus, generally in the middle and lower forest strate.     

A checklist of Lecythidaceae in the upper Madeira River,Rondônia,Brazil with comments on diversity and conservation

The Lecythidaceae or Brazil Nut family are ubiquitous in non-flooded lowland forests of the Amazon, where they are indicative of well-preserved or little-disturbed habitats. A recent checklist of the Brazilian flora reported 10 genera and 119 species for that country, of which 104 are found in the Amazon region. However, the botanical knowledge in many regions of the country remains far from complete. This study aimed to analyze the diversity of Lecythidaceae in the upper Madeira River region in Rondônia, an area where botanical data is scarce. Lecythidaceae collections deposited in the CEN, INPA and RON herbaria were examined, and four field expeditions in the study area were carried out. For that region, we recorded 37 species of Lecythidaceae belonging to 7 genera: Eschweilera (21 species), Couratari (6), Cariniana (3), Gustavia (3), Allantoma (2), Bertholletia (1) and Lecythis (1). Among these species, five are listed as threatened in the IUCN Red List. The total number of species found in the upper Madeira River of Rondônia alone is higher than the 28 species reported to date for the entire state of Rondônia in the Brazilian Flora Checklist (Smith et al., 2015), and adds 13 new records of Lecythidaceae for the state. Considering that this study is restricted to the northern part of the state, our results suggest that the number of Lecythidaceae species in Rondônia is severely underestimated. Our findings highlight the need for more intensive floristic studies in the Amazon region, which should target areas that are botanically unexplored but have high biodiversity potential. Such studies will provide valuable information to support both taxonomic studies and species conservation assessments.     

Rotavirus and adenovirus in Rondônia

Acute gastroenteritis is one of the most common diseases in humans worldwide. Viral gastroenteritis is a global problem in infants and young children. In this study the incidence of diarrhea was assessed in 877 hospitalized children under five years old, over a period of 24 months and distributed in 470 cases of diarrhea and 407 age-matched group with other pathologies, as control group. Two antigen detection techniques based on enzyme immunoassay (EIA) and latex particles were used for detection of rotavirus and adenovirus. Rotavirus A was a major cause of gastroenteritis with 23.6% of cases, being 90% of these cases in young children. Adenovirus infections was detected by EIA with frequency of 6.4%. Rotavirus and adenovirus were detected in 10.1 and 1.7% of stools from control group, respectively. Interestingly, the frequency of the youngest children in the control group excreting Rotavirus A was comparable to that detected in stools from diarrheic children. We cannot rule out the existence of other enteric viruses because the etiology of 171 cases of diarrhea was not determined and active search for astrovirus and calicivirus was not done. This is the first study that shows the presence of enteric viruses in the infantile population from Western Brazilian Amazonia and it was important to help physicians in the treatment of viral gastroenteritis.     

Land Use Patterns in the Brazilian Amazon: Comparative Farm-Level Evidence from Rondônia

Since the 1970s the Brazilian Amazon has received over 1 million migrant farm households from other regions of the country, many of whom were attracted to government-sponsored frontier settlement programs that offered free tropical forest land. As a result, pressures on tropical forests have intensified along several settlement corridors throughout the region. Despite their importance as agents of landscape change, surprisingly little is known about the land use practices of these farmers. This paper briefly reviews the research literature on smallholder land use patterns in Amazonia, describes the recent history of one important agricultural land settlement program in the western Brazilian Amazon state of Rondônia, and, based on 240 household surveys conducted in three separate settlement locations in the state, highlights key differences in land use patterns among the rural population. Typologies of farming systems are presented on the basis of cluster analysis of land use data and ANOVA tests. The findings indicate considerable complexity and heterogeneity in smallholder farming systems. Spatial variations in farming system types may be due to geographic differences in soil regimes, the social histories of specific communities, and site-specific responses to exogenous variables.     

Effects of Land-Use Change on Soil Nutrient Dynamics in Amazônia

Over the past several decades, the conversion of native forest to agricultural land uses has accelerated across the Amazon Basin. Despite a growing body of research on nutrient dynamics in Amazonian primary forest and forest-derived land uses, the effects of widespread land-use change on nutrient contents and cycles in soil and vegetation are not well understood. We reviewed over 100 studies conducted in Amazônia over the past 40 years on nutrient dynamics in natural forests and forest-derived land uses (pasture, shifting cultivation, and tree plantations). Our objectives were to compare soil data from land uses across Amazônia and identify any gaps in our present knowledge that might offer direction for future research. Specifically, by analyzing data we tested the following five widely cited hypotheses concerning the effects of land-use change on soil properties compiled from 39 studies in multifactorial ANOVA models; (a) soil pH, effective cation exchange capacity (ECEC), and exchangeable calcium (Ca) concentrations rise and remain elevated following the slash-and-burn conversion of forest to pasture or crop fields; (b) soil contents of total carbon (C), nitrogen (N), and inorganic readily extractable (that is, Bray, Mehlich I, or resin) phosphorus (P_i) decline following forest-to-pasture conversion; (c) soil concentrations of total C, N, and P_i increase in secondary forests with time since abandonment of agricultural activities; (d) soil nutrient conditions under all tree-dominated land-use systems (natural or not) remain the same; and (e) higher efficiencies of nutrient utilization occur where soil nutrient pools are lower. Following the conversion of Amazonian forest to pasture or slash-and-burn agriculture, we found a significant and lasting effect on soil pH, bulk density, and exchangeable Ca concentrations. Unlike the other three land uses studied, concentrations of extractable soil P_i were equally low in both forest and pastures of all age classes, which demonstrates that postburning pulses in soil P_i concentration following a slash-and-burn decrease rapidly after forest-to-pasture conversion, perhaps due to accumulation in organic P fractions. Neither the concentrations nor the contents of total C and N appeared to change greatly on a regionwide basis as a result of forest-to-pasture conversion, but surface soil C:N ratios in 5-year-old pastures were significantly higher than those in older pastures, suggesting changes in the soil concentrations of at least one of these elements with time after pasture creation. Pasture soils did have higher total C and N concentrations than land uses such as annual cropping and secondary forest fallow, indicating that soil C and N maintenance and/or accumulation following forest conversion may be greater in pastures than in these other two land uses. The low concentrations of C and N in shifting cultivation soils appear to persist for many years in secondary forests regenerating from abandoned crop fields, suggesting that the recuperation of soil losses of C and N resulting during no-input annual cropping is slower than previously thought. Soil C, N and P concentrations were strongly related to clay content. Across all land uses, efficiencies of N, P, and Ca use (estimated as the inverse of litterfall N, P, and Ca contents) were not related to the sizes of their soil pools. More work is needed to test and standardize P extraction procedures that more accurately reflect plant availability. Few studies have been conducted to determine the role of organic P fractions and dissolved organic N (DON) in the elemental cycles of both natural and managed systems in this region. In general, we recommend further study of annual and perennial cropping systems, as well as more detailed examination of managed pastures and fallows, and secondary forests originating from various disturbances, since the intensity of previous land use likely determines the degree of soil degradation and the rate of subsequent secondary regrowth.     

Temporal changes of mangrove vegetation boundaries in Amazônia: Application of GIS and remote sensing techniques

The present work analyses a 25-year timeseries of radar and satellite images, andidentifies areas with losses and gains ofvegetation coverage along 166 km of Para'scoastline (North Brazil) and in the innerparts of the Bragança peninsula. Thegeomorphology of this region hassignificantly changed in recent years. Aresult of these changes has been a retreatof the mangrove vegetation along thecoastline, mainly due to landward sandmigration, which covers the mudflat andasphyxiates the vegetation. Image analysissuggests that the loss of vegetationcoverage has been the dominating process inthe last 25 years, occurring on 42% ofthe Bragança coastline and adjacentareas. Vegetation has remained stable along 39% of the coastline, while mudsedimentation has allowed mangrovedevelopment along 19% of it. On the otherhand, during this period of time, mangroveshave invaded 3.4 km² ( 38%) of theelevated herbaceous flats in the highestsectors of the Bragança peninsula.Despite other possible causes for mangrovedeath along the coastline, such as littoraldrift currents or cyclical changes incoastal sediment dynamics, the invasion ofmangrove into herbaceous elevated flats inthe central peninsula cannot be attributedto these factors. The current dynamics ofvegetation coverage change seem to becompatible with a long-term trend relatedto the predicted rates of sea-level rise.     

Enteropathogens associated with diarrheal disease in infants of poor urban areas of Porto Velho, Rondônia: a preliminary study

One hundred and thirty cases of diarrhea and 43 age-matched controls, 0 to 5 years old, were studied in a pediatric outpatient unit from a poor peri urban area of Porto Velho, Rond?nia. Eighty percent of diarrheal cases were observed in the groups under 2 years of age. Rotavirus (19.2%) was the most frequent enteropathogen associated with diarrhea, followed by Shigella flexneri (6.15%) and S. sonnei (1.5%) and Salmonella sp. (6.9%). Four cases of E. coli enterotoxigenic infections (3.1%), E. coli enteropathogenic (EPEC)(2.3%) one case of E. coli enteroinvasive infection (0.8%) and one case of Yersinia enterocolitica (0.8%) were also identified. Mixed infections were frequent, associating rotavirus, EPEC and Salmonella sp. with Entamoeba histolytica and Giardia lamblia.     

Palm taxonomy in Brazilian Amazônia: The state of systematic collections in regional herbaria

Despite their economic and ecological importance, Amazonian palms have been largely neglected by contemporary taxonomists. The resulting confusion at the specific level is a serious impediment to research efforts by specialists in other fields. To assess the state of systematic collections presently available in Amazônia, we conducted a survey of the palm specimens in three Brazilian herbaria (MG, IAN and INPA). Twelve criteria were utilized to measure the quality of the specimens. We found that most of the 897 specimens are reasonably complete in a physical sense, but a large proportion lack crucial information on their labels. Curating facilities are in serious need of improvement, as is evident from the significant (26%) percentage of specimens found to be in an unreasonable state of preservation. A checklist of the 232 currently recognized palm species in Brazilian Amazônia shows that 145 (62.5%) are not represented by identified specimens, and that the representation which does exist lacks depth. To improve the quality and representativeness of collections in regional herbaria, we suggest procedures for collecting and storing palms as well as policies designed to intensify collecting efforts in Amazônia.     

Malaria control in an agro-industrial settlement of Rondônia (Western Amazon region, Brazil)

A malaria control pilot project was developed in the Urupá agro-industrial farm that is situated in the State of Rond?nia (Western Amazon Region, Brazil). Around 180 inhabitants had been surveyed for the past five years. The control measures were based on (1) training a community agent to perform on the spot microscopical diagnosis of malaria and to treat the uncomplicated cases of malaria; (2) limiting the use of insecticides to a short period before the high transmission season. This resulted in a significant reduction in the time between the onset of clinical symptoms and specific chemotherapy which fell from 3.5 to 1.3 days. In relation to the previous three reference years the total number of malaria cases was reduced to 50% in the first year and to 25% in the second year. The introduction of these measures coincided with pronounced reduction in the frequency of Plasmodium falciparum infections but this was less marked for P. vivax infections. In the second year of the pilot experiment there was no P. falciparum transmission on the farm. During the last decade there was a general decrease in the endemicity of malaria in the State of Rond?nia. The linear regression coefficient values indicate that the decline was more pronounced in Urupá than in the general municipality and that the falciparum malaria API in Urupá farm is significantly lower than in the general municipality of Candeias were the farm is situated.     

Distribution of the CCR5delta32 allele (gene variant CCR5) in Rondônia, Western Amazonian region, Brazil

Since around 1723, on the occasion of its initial colonization by Europeans, Rondonia has received successive waves of immigrants. This has been further swelled by individuals from northeastern Brazil, who began entering at the beginning of the twentieth century. The ethnic composition varies across the state according to the various sites of settlement of each wave of immigrants. We analyzed the frequency of the CCR5Δ32 allele of the CCR5 chemokine receptor, which is considered a Caucasian marker, in five sample sets from the population. Four were collected in Porto Velho, the state capital and the site of several waves of migration. Of these, two, from the Hospital de Base were comprised of HB Mothers and HB Newborns presenting allele frequencies of 3.5% and 3.1%, respectively, a third from the peri-urban neighborhoods of Candelária/Bate-Estaca (1.8%), whereas a fourth, from the Research Center on Tropical Medicine/CEPEM (0.6%), was composed of malaria patients under treament. The fifth sample (3.4%) came from the inland Quilombola village of Pedras Negras. Two homozygous individuals (CCR5Δ32/CCR5Δ32) were detected among the HB Mother samples. The frequency of this allele was heterogeneous and higher where the European inflow was more pronounced. The presence of the allele in Pedras Negras revealed European miscegenation in a community largely comprising Quilombolas.     

Black piedra among the Zoró Indians from Amazônia (Brazil)

A total of 130 Zoró Indians from the Brazilian Amazon were observed as part of an epidemiological survey. Black piedra was found in 74 (56.9%) individuals. Infection rates between the sexes were not significantly different. The age group least infected comprised the children, 0–10 years of age. The authors comment on the epidemiology of the infection among the Zoró.     

The role of the shrub Cordia multispicata Cham. as a ‘succession facilitator’ in an abandoned pasture,Paragominas, Amazônia

We studied the conditions that permit the shrub, Cordia multispicata, to establish in Amazon pastures and the potential role of this shrub as a succession facilitator near the town of Paragominas, Pará State, Brazil. Local disturbances that reduce cover such as grazing and burning helped C. multispicata establish in pastures in active use. Germination of C. multispicata was significantly improved on sites subjected to simulated grazing and seedling growth was hastened following pasture burning. We found that below-ground competition, evaluated using root ingrowth cores, was reduced by burning and grazing. Recently abandoned pastures are frequently composed of a mix of forbs and grasses but as succession proceeds a mosaic of more discrete vegetation patches appears. At our site, a five-year-old abandoned pasture, grass patches (primarily Panicum maximum) and shrub patches (mainly C. multispicata) were common. We compared physical and biotic characteristics of zones dominated by C. multispicata and P. maximum and found: (1) the rain of bat and bird dispersed seeds of woody species was much greater in the zones of C. multispicata (92 seeds/m²/year) than in the patches of grass (6 seeds/m²/year); (2) the density of woody seedlings was eight times greater in the C. multispicata patches (0.65/m²) than in the zones of P. maximum (0.08 woody individuals/m²); (3) soil nutrient availability and litter nutrient concentrations were greater in the shrub zones than in the grass zones; and (4) photosynthetic photon flux density at the soil surface was generally more favorable for rainforest tree seedling growth in C. multispicata patches (16% of full sunlight) as compared to the grass zones (7.7% of full sun). We conclude that the shrub, C. multispicata, acts as a magnet, attracting volant seed vectors, and as a nurse plant, facilitating the establishment of woody species in abandoned Amazon pastures.     

Ecophysiological traits of plant functional groups in forest and pasture ecosystems from eastern Amazônia,Brazil

The plant functional group approach has the potential to clarify ecological patterns and is of particular importance in simplifying the application of ecological models in high biodiversity ecosystems. Six functional groups (pasture grass, pasture sapling, top-canopy tree, top-canopy liana, mid canopy tree, and understory tree) were established a priori based on ecosystem inhabited, life form, and position within the forest canopy profile on eastern Amazonian region. Ecophysiological traits related to photosynthetic gas exchange were then used to characterize such groups. The ecophysiological traits evaluated showed considerable variations among groups. The pasture grass functional group (a C₄ photosynthetic pathway species) showed high instantaneous water use efficiency (A _max/g _s@A _max), high photosynthetic nitrogen use efficiency (A _max/N _area), and high ratio of A _max to dark respiration (A _max/R _d). Among the species with the C₃ photosynthetic pathway, the top-canopy liana group showed the highest mean of A _max/g _s@A _max, statistically distinct from the lowest average presented by the understory tree group. Furthermore, the pasture sapling group showed the lowest average of A _max/R _d, statistically distinct from the high average observed for the understory tree group. Welch-ANOVAs followed by Games–Howell post hoc tests applied to ecophysiological traits produced reasonable distinctions among functional groups, although no significant distinction was detected between the groups top-canopy tree and pasture sapling. Species distribution within the functional groups was accurately reproduced by discriminant analyses based on species averages of ecophysiological traits. The present work convincingly shows that the functional groups identified have distinct ecophysiological characteristics, with the potential to respond differently to environmental factors. Such information is of great importance in modeling efforts that evaluate the effects of dynamic changes in tropical plant communities over ecosystem primary productivity.     

Nitrogen oxide emissions following wetting of dry soils in forest and pastures in Rondônia, Brazil

Rains at the end of the dry season can trigger increases in emissions of nitric oxide (NO) and nitrous oxide from forest and pasture soils in the Amazon Basin. The relative importance of the rain-stimulated emissions in the seasonal and annual budgets of these nitrogen gases for forests and pastures in the western Amazon is not well established. We measured soil emissions of NO and N₂O from a forest and two pastures, 11 and 26 years old, after a simulated rain event. Wetting the soil resulted in very small pulses of NO or N₂O from forest soils and no significant NO or N₂O pulses from the pastures. We estimated that in the forest, the amounts of each gas emitted from pulses during the dry to wet transition period represented 3.4% of the NO and 1.8% of the N₂O dry-season emissions, but amounted to less than 2% of the annual emissions of either gas. Total N oxide emissions of 5.6 kg N/ha/yr from the forest were nearly evenly divided between NO (42%) and N₂O (58%). The emissions of NO were evenly distributed over the wet and dry seasons, while over 84% N₂O fluxes occurred during the wet season.     

The rôle of the spermathecal gland of the boll weevil,Anthonomus grandis

Spermatozoa were relatively inactive and did not enter the spermatheca of female boll weevils, Anthonomus grandis, whose spermathecal glands were removed as teneral adults. However, these females were able to lay fertile eggs for a 2 week period. When the spermathecal gland was removed from older females, spermathecal filling occurred, and although the spermatozoa retained their fertilizing capacity for extended periods, spermathecal emptying did not occur. Spermatozoa gradually lost their motility and fertilizing capacity, indicating that spermathecal secretions are effective in very small amounts. Spermatozoa were not activated by any of the materials contained in the normal male ejaculate. These materials alone did not effect spermathecal filling nor were they capable of maintaining the fertilizing capacity of the spermatozoa for very long. Sperm economy is low with less than 1 fertile egg laid per 100 spermatozoa used.