Instituto Nacional de Pesquisas da Amazônia
Recent publications
The Atlantic and Amazon rainforests have a shared but unclear past, with intermittent connections resulting from historical climate change. We investigate these connections by studying the phylogeography and climatic niche of the disjunct distributed frog Lithobates palmipes. We sequenced two fragments of mitochondrial DNA from Atlantic Forest (AtF) and Amazonia (AmF) individuals and evaluated how genetic diversity is distributed in space and whether past demographic changes occurred. Also, we evaluated the existence of past suitable connections between biomes for L. palmipes through ecological niche models (ENM) and tested for niche divergence. The AtF group is nested within the AmF group and closely related to individuals from eastern Amazonia, a pattern recovered in many species that used northeast connection routes. We found evidence of recurrent use of connections in different directions and time during the Pleistocene, resulting in genetic structure between biomes, with no signal of demographic change and evidence of niche divergence across both genetic groups. ENMs indicated suitable areas connecting forests throughout northeastern Brazil during the Pleistocene. Mitochondrial lineages do not match biomes exactly. One lineage is composed of AtF populations and eastern Amazonia individuals. The other is composed of western Amazonia individuals, suggesting an effect of past climatic heterogeneity within the Amazonia forest. This is the first evidence that this route drove genetic and ecological diversity for amphibians recently, a group with habits and ecological requirements different from other vertebrates that have been shown to use this putative corridor.
Cryptic diversity is extremely common in widespread Amazonian anurans, but especially in nurse frogs of the genus Allobates . There is an urgent need to formally describe the many distinct but unnamed species, both to enable studies of their basic biology but especially to facilitate conservation of threatened environments in which many are found. Here, we describe through integrative taxonomy a new species of the Allobates tapajos species complex from the upper Madeira River, southwestern Amazonia. Species delimitation analyses based on molecular data are congruent and delimit five candidate species in addition to A. tapajos sensu stricto. The new species is recovered as sister to A. tapajos clade F, a candidate species from Teles-Pires River, southeastern Amazonia. The new species differs from nominal congeners in adult and larval morphology and in male advertisement call. Egg deposition sites differ between east and west banks of the upper Madeira River, but there is no evidence of corresponding morphologic or bioacoustic differentiation. The new species appears to be restricted to riparian forests; its known geographic range falls entirely within the influence zone of reservoirs of two large dams, which underscores the urgent need of a conservation assessment through long-term monitoring. This region harbors the richest assemblage of Allobates reported for Brazilian Amazonia, with six nominal species and four additional candidate species awaiting formal description.
The tension between the large global demand for tropical timber, and ecological sustainability and local socioeconomic development in the fragile natural ecosystems of the Amazon region has challenged many generations. In this case study, carried out in an ecotone forest in the northern Brazilian Amazon, we seek to demonstrate how forest management can became more sustainable through silvicultural prescriptions that reduce forest degradation and soil erosion. We evaluated the effects of the sustainable forest management (SFM) on tree diversity, timber volumes, and carbon stocks. A continuous forest inventory was carried out in nine 1-ha permanent plots (900 subplots of 100 m²), distributed in three treatments with three repetitions: T1 = control without selective logging, T2 = SFM, and T3 = SFM + silvicultural treatment of thinning release by tree girdling and poisoning. SFM was carried out with an average of three commercial timber trees harvested per hectare with DBH (diameter at breast height) ≥ 50 cm, corresponding to a timber volume of 20 ± 6 m³ ha⁻¹, equivalent to the removal of 7 ± 2 Mg C ha⁻¹ (5% of the original C). The formation of clearings (gaps) arising from the falling of exploited trees (0.12 ± 0.09 ha) resulted in greater impacts on the forest structure than the construction of 4 m skidder trails (0.06 ± 0.04 ha), with an average of 7 ± 4 damaged trees ha⁻¹ and 5 ± 3 dead trees ha⁻¹. Although six trees species became locally extinct, tree diversity was little altered, and timber volumes and forest carbon volume stocks remained essentially constant at this average logging intensity. Based on our results, sustainable forest management can become an efficient model for land use in the Amazon when harvesting is carried out using this average logging intensity. However, long-term monitoring studies using permanent plots in ecotone forests in the Brazilian Amazon will still be necessary. Quantifying, evaluating, and reporting impacts related to forest management will enable the formation of an empirical basis to support sustanaible forestry practices and for updating environmental legislation, contributing to local socioeconomic development, and maintaining the environmental services provided globally by tropical forests.
Geastrum is a genus with worldwide distribution and the most species-diverse in the family Geastraceae and is easily recognized by the star-like basidioma in the majority of species. The most recent and accepted classification based on phy-logenetic, morphological and chemical data, subdivided the genus into 14 sections. The section Exareolata is formed by eleven species from which only G. echinulatum and G. verrucoramulosum are truly stipitate. During field trips in Brazilian Amazonia, we found a stipitate species of Geastrum. Based on morphological and phylogenetic data, we propose it as a new species for the genus, which forms a sister group of G. verrucoramulosum and is allocated in sect. Exareolata. Geastrum squameoramulosum sp. nov. is characterized by a prominent and well-developed ramified stipe and the presence of scales on the outer surface of the exoperidium. It is known so far only from the Amazon rainforest. We also provide an updated key to the species in this section.
The reliable identification of the fish species found in Amazonian streams requires a considerable investment of both time and resources, which often hampers the biodiversity pattern mapping and conservation planning. This problem can be overcome using biological surrogates such taxonomic families, this would reduce the number of fish to be identified and thus facilitate the development of studies. The present study analyzes the potential of families as surrogates of the fish diversity of Amazonian streams. For this, we verified the degree of congruence between the distribution of species organized by family and the composition of the assemblage in two different spatial scenarios. At the biome scale, we verified the degree of congruence in the fish faunas of 54 streams located within six drainage basins in Brazilian Amazonia. At the regional scale, we compared the data from the basins located on the lowland floodplain and those at higher altitudes. The Cichlidae and Lebiasinidae were identified as potential biological surrogates at both spatial scenarios, demonstrating more than 80% similarity with species matrix in all the analytical approaches. The families Crenuchidae and Hypopomidae were the most congruent with the fish from the floodplain basins, both were more than 80% congruent with the species matrix. In upland basins, Characidae, Gymnotidae and Rivulidae were highly similar to the species matrix, in particular Gymnotidae and Rivulidae with more than 90% similarity. Overall, we can conclude that the biological surrogacy approach is a potentially valuable alternative for species diversity evaluation of Amazonian streams ecosystems, considering the accelerated loss of the diversity of these systems.
This work reports on the concentration of dissolved ions and identifies water chemistry patterns by the analysis of 79 water samples from rivers and streams in the Jaú and Uatumã basins, Negro and Solimões/Amazon rivers in the Brazilian Amazon central part. This dataset was analyzed by means of a principal component analysis (PCA) followed by a one-way analysis of similarities (ANOSIM) and a Neighbor Joining Cluster analysis of the samples, explaining 50.8% of the limnological data variation, which was strongly influenced by electrical conductivity, alkalinity, Fe total, P total, NH4, Fe dissolved, SiO2 and pH. This analysis showed the formation of five groups such as: 1) Solimões-Amazon River; 2) Jaú basin streams; 3) Padre stream; 4) Jaú and Carabinani rivers (Jaú basin); and 5) Uatumã basin streams, Uatumã and Abacate rivers, and Negro River. These waters showed typical Amazonian characteristics, with the exception of the Jaú River and the Padre stream. The hydrochemical parameters of the former did not correspond to the typical values of Amazonian blackwater rivers. The mean concentrations of color, COD, chloride, NH4 and dissolved iron of the latter are unusually high if compared with other rivers and streams on the Uatumã basin. However, the K and silica concentrations were exceptionally lower than those of other Uatumã basin streams. The evaluated samples from the Jaú and Uatumã basins could fit within the current classification as Intermediate Type A. Furthermore, the Jaú River, during low water period, could fit within the Intermediate Type B category according to its geochemical features. This chemical characterization is extremely important when it comes to water Brazilian legislation and its adjustments for inclusion of the Amazon region waters. Hence, this paper may contribute to understanding such water chemical patterns, and to water resources management and conservation of these Amazon aquatic ecosystems.
Most of the basal area in Amazon forest is in large trees, many of which are species of interest for forest management. In forest management these trees are divided into the commercial bole that is harvested for wood production and the stump and crown that are left in the forest where they decompose and emit CO2 over a period of years. Part of the commercial bole is converted to wood products that store carbon according to their durability. The quantification of these components is difficult due to their size, especially in the case of the crown, which causes uncertainties in the estimates of biomass and carbon. Our study estimated the aboveground biomass and carbon of 223 trees and subsequently fit allometric equations to these estimates. Aboveground biomass was calculated from stem volume, wood density and a biomass expansion factor, while total carbon stock estimates used carbon content determined in the laboratory. Linear models (log-transformed) were tested to derive the best-fit allometric model for total aboveground biomass and carbon. The best-fit selected allometric models used squared tree diameter, tree height, and wood density for biomass, whereas the best carbon model also used carbon content. Our models were more efficient in estimating biomass than were frequently used regional and pan-tropical models. Our equations allow reducing the errors in estimates of forest biomass and carbon stocks, in addition to allowing estimation of the amount of carbon emitted after harvest, although the other models also had good fits and can be used according to the criteria of each researcher and the availability of data.
We used experimental chambers to evaluate the effect of the temperature increasing and microbial conditioning degree on the survival and leaf consumption of two plant species [Protium spruceanum (Burseraceae) and Goupia glabra (Celastraceae)] by larvae of the shredder Phylloicus elektoros. We also evaluated the sporulation rate of the conditioned leaf debris. The leaf discs were incubated for 0, 7, and 15 days in a stream. Posteriorly, the treatments were inserted in chambers with temperatures of 23.2 °C and 27.5 °C. The higher sporulation rate was found in leaves of G. glabra, with no difference in sporulation among the microbial conditioning treatments. The larval survival was lower in treatments with leaves of P. spruceanum, and in the warming temperature. The microbial conditioning time did not influence larval survival. The effect of the conditioning time and temperature on the leaf consumption depended on the plant species. The foreseen temperature increases and reduction of the palatability of the leaves due to the climate change may result in negative effects on the leaf consumption and survival of larvae of P. elektoros.
The Amazon region may present a high diversity of endoparasites with a high degree of endemism. In this sense, this study describes the endoparasite fauna in freshwater fish from the Upper Juruá, in the Western Amazon. The study was carried out around the municipalities of Cruzeiro do Sul, state of Acre, and Guajará, state of Amazonas, Brazil. Fish were caught between periods of droughts and floods, using passive and active sampling methods. In the laboratory, specimens were biometrically analysed and necropsied. As a result, a total of 23,740 endoparasites were recorded, belonging to 62 species, with 91 new host reports and 91 new occurrences for the Western Amazon. Nematoda and Digenea were the most diverse and abundant groups, and the increase in host fish richness and diversity influenced the diversity and richness of endoparasites in the environments. In this sense, the present study expands the number of new reports, and contributes data on the distribution and richness of endoparasites for South America.
Distribution data sharing in global databases (e.g. GBIF) allowed the knowledge synthesis in several biodiversity areas. However, their Wallacean shortfalls still reduce our capacity to understand distribution patterns. Including exclusive records from other databases, such as national ones (e.g. SpeciesLink), could mitigate these shortfall problems, but it remains not evaluated. Therefore, we assessed whether (i) the inventory completeness, (ii) taxo-nomic contribution and (iii) spatial biases could be improved when integrating both global and national biodiversity databases. Using Amazonian epiphytes as a model, we compared the available taxonomic information spatially between GBIF and SpeciesLink databases using a species contribution index. We obtained the inventory completeness from sources using species accumulation curves and assessed their spatial biases by constructing spatial autoregressive models. We found that both databases have a high amount of exclusive records (GBIF: 36.7%; SpeciesLink: 21.7%) and species (17.8%). Amazonia had a small epiphyte inventory completeness, but it was improved when we analyzed both databases together. Individually, both database records were biased to sites with higher altitude, population and herbarium density. Together, river density appeared as a new predictor, probably due to the higher species contribution of SpeciesLink along them. Our findings provide strong evidence that using both global and national databases increase the overall biodiversity knowledge and reduce inventory gaps, but spatial biases may persist. Therefore, we highlight the importance of aggregating more than one database to understand biodiversity patterns, to address conservation decisions and direct shortfalls more efficiently in future studies.
Nitrogen‐fixing symbiosis is globally important in ecosystem functioning and agriculture, yet the evolutionary history of nodulation remains the focus of considerable debate. Recent evidence suggesting a single origin of nodulation followed by massive parallel evolutionary losses raises questions about why a few lineages in the N2‐fixing clade retained nodulation and diversified as stable nodulators, while most did not. Within legumes, nodulation is restricted to the two most diverse subfamilies, Papilionoideae and Caesalpinioideae, which show stable retention of nodulation across their core clades. We characterize two nodule anatomy types across 128 species in 56 of the 152 genera of the legume subfamily Caesalpinioideae: fixation thread nodules (FTs), where nitrogen‐fixing bacteroids are retained within the apoplast in modified infection threads, and symbiosomes, where rhizobia are symplastically internalized in the host cell cytoplasm within membrane‐bound symbiosomes (SYMs). Using a robust phylogenomic tree based on 997 genes from 147 Caesalpinioideae genera, we show that losses of nodulation are more prevalent in lineages with FTs than those with SYMs. We propose that evolution of the symbiosome allows for a more intimate and enduring symbiosis through tighter compartmentalization of their rhizobial microsymbionts, resulting in greater evolutionary stability of nodulation across this species‐rich pantropical legume clade.
1. The seasonality of tropical rivers, induced mainly by water level changes, shapes many interrelated aspects of ecological communities and the populations they contain, including animal movement, feeding, growth, and reproductive activity. However, the role played by seasonality in structuring the diversity of tropical assemblages is not yet fully understood. 2. We examined the effects of seasonality on community structure and composition of benthic fish assemblages comparing two consecutive receding and rising water seasons in a major tributary of the Amazon basin. We quantified seasonal shifts in species abundance distributions and in composition using a multivariate dispersion test, total β diversity and its decomposition into local (LCBD) and species contribution to β diversity (SCBD). Additionally, we tested for relationships between LCBD values and richness, total abundance, and environmental variables. 3. Many benthic fish species were rare in terms of numerical abundance. Rarity was most pronounced in the rising seasons, which had a higher proportion of singletons. A logseries was the best-fit model for both the receding and one of the rising season's species abundance distributions, while a lognormal was selected for the second rising season. We detected variation in species composition between seasons—the rising seasons were distinct from one another in terms of species composition, as well as differing from the receding seasons. LCBD showed strong negative relationships with species richness and total abundance, particularly in the rising seasons, indicating that seasons with high uniqueness in their composition also had low richness and abundance. LCBD was negatively correlated with temperature, while depth presented a positive relationship, as observed mainly in rising seasons with colder temperatures and greater water depth. Approximately one third of the species had higher than average SCBD values and were considered major contributors to β diversity. 4. These significant seasonal differences in both species relative abundances and assemblage composition might be explained by the asymmetrical spatial use of habitats during different seasons, strongly suggesting the importance of the flood–pulse cycle for maintaining diversity in this environment. 5. Studies that seek to identify the species inhabiting a particular environment (e.g. bottom rivers habitats) and the factors that affect the dynamics, structure and composition of these communities are fundamental for future management and conservation. This is particularly urgent for understudied tropical freshwater ecosystems, as human pressures including anthropogenic climate change are expected to become increasingly severe. Rising temperatures and changing precipitation patterns modify water temperature and flow regimes, thus affecting the hydrologic regime that determines the structure and dynamics of the ecological communities, with potential consequences for their integrity.
Wild pigs (Sus scrofa L.) are considered one of the 100 worst invasive species, causing adverse social, economic, and environmental impacts worldwide. Understanding their historical invasion process and following the distribution across the territory can serve as a preoccupant alert for the species’ quick expansion. Our goal was to update the information about the invasion history and spatial distribution of wild pigs in Brazil. Using extant occurrence records in the literature and from official agencies, we built distribution maps of wild pigs’ distribution in Brazil over time. We identified wild pigs reports in 1152 municipalities across the country, primarily concentrated in the southeast region of Brazil (52.95%). Our results revealed an accelerated increase of wild pigs in the last 30 years, especially across the southern, southeast and mid-west regions. This reinforces the need for immediate measures to control wild pigs and halt expansion. This is the first research showing complete historical invasion of wild pigs in Brazil.
Atopocelyphus ruficollis (Macquart, 1844) is the only known species of Celyphidae to occur in the Neotropical region, registered only in French Guiana. Here we provide the first record of this species and family for Brazil, based on material collected in Oyapock, Amapá state, along with detailed photographs of male and female terminalia.
A new species of dobsonfly from Venezuela, Corydalus ralphi Martins, Azevêdo, Hamada & Contreras, sp. nov. , was discovered a decade after the last description of a species of this genus in the country. The new species is morphologically similar to C. wanningeri Contreras-Ramos & von der Dunk, sharing a uniform reddish coloration of body and wings and similar male genitalic structures. Likewise, it shares this particular coloration with C. neblinensis Contreras-Ramos but the genitalic structure fits within the C. crossi Contreras-Ramos species group. Two specimens, one male and one female, were collected on Tarotá River, in the Gran Sabana region, Canaima National Park, in southern Venezuela. A key to identify males of the Venezuelan species of Corydalus is provided.
The long-horned caddisfly genus Notalina Mosely, 1936 contains 27 species divided into two subgenera. The Neotropical N. (Neonotalina) Holzenthal, 1986 occurs exclusively in South America. Its species are organized into two species groups, brasiliana and roraima . Nine species have been recorded so far in Brazil, mainly distributed in the Cerrado and Atlantic Forest biomes of Southeast Region, and only one species has been recorded from the Central-West and Northeast Regions. In this paper a new species of N. (Neonotalina) is described and illustrated based on adult males from two protected and preserved areas in the Cerrado biome of Brazil. Notalina (Neonotalina) ralphi sp. nov. belongs to the brasiliana species group and can be recognized mainly by the morphology of the preanal appendages and segment X. New distributional records are provided for N. (Neonotalina) brasiliana Holzenthal, 1986. Additionally, a key to identify males of the ten species in the brasiliana species group is provided.
This work aimed to assess if nonlinear models accurately predict the wood productive capacity of B. excelsa plantations in Amazonia and identify topoedaphic characteristics more linked to growth variations in these plantations. Nonlinear models were tested to classify the productive capacity of B. excelsa stands of different ages (14 to 21 years), by algebraic difference method. We used a database of 75 temporary plots and complete stem analyses of 30 trees. Soil sampling was performed at depths of 0–20 cm and 20–40 cm, for chemical analyses ( pHH2O , pHKCl, C, P, K+, Ca2+, Mg2+, Al3+, Fe2+, Mn2+, Zn2+ and Na+) and physical (soil density, penetration resistance, granulometry). Topographic information was obtained by GPS and digital elevation image. Site classes were spatialized in the study area by method ordinary point kriging. Relationships between topoedaphic variables and site index were evaluated by correlation matrix to identify major characteristics limiting site productivity, and regression models were generated by stepwise backward method to evaluate whether topoedaphic characteristics explain growth variation in B. excelsa stands. The Chapman-Richards model presented good statistical performance, good distribution of residues, and resulted in consistent polymorphic curves. Polymorphism evaluation indicated differentiated growth patterns of specie among sites. Soil texture (sand content) and topography (elevation) were the main drivers of site productivity, followed by some soil chemical variables (K+, Mn2+ and pHKCl). These results can support planning of activities related to installation and management of B. excelsa stands in the Amazon, besides identifying potential areas of expansion of plantations of this species.
Increasing food production while preserving natural ecosystem services linked to native biodiversity is one of the most important societal challenges in the 21st-century. Natural pollination performed by bees significantly increases yields even in crops that do not strictly depend on animal pollination, such as soybean. However, several factors, such as habitat loss and degradation, have contributed to the decline in abundance and diversity of bees. Here, we assess the effects of the type, complexity and amount of native habitats on Neotropical bee assemblages within agricultural landscapes. We sampled bees at 43 landscapes in the state of Mato Grosso, Brazil, within a region encompassing Amazonian rainforests, the drier Cerrado savannahs, and transitional vegetation between these biomes. We collected 1359 individuals representing 134 bee species. Bee species richness differed between soybean and core native only in Amazonian forest landscapes, while species composition differed in both forest and transition landscapes. Overall bee species richness did not differ between the three vegetation types, but species composition in forest landscapes diverged from those in transition and Cerrado areas. The amount of native habitat remaining had a positive effect on both species richness and composition. Our results show that the relentless replacement of natural ecosystems with soybean monoculture detrimentally affects bee species richness, and substantially changes the species composition. Pollinator decline has negative consequences for economics and biodiversity conservation. Therefore, we suggest that areas of native vegetation should be protected and monitored due their crucial importance for maintain biodiversity and ecosystem services through the landscape. Ideally, we suggest that strategies for the conservation of bee diversity consider the amount of native habitats at landscape scale.
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890 members
Antonio Pontes
  • Coordenação de Assuntos Estratégicos (COAE)
Daniell Rodrigo Rodrigues Fernandes
  • Programa de Pós Graduação em Entomologia (PPGEnto)
José Celso De Oliveira Malta
  • Coordenação de Pesquisas em Biodiversidade (CBIO)
Noemia Kazue Ishikawa
  • Coordenação de Biodiversidade (CBIO)
Reinaldo Imbrozio Barbosa
  • Núcleo de Pesquisas de Roraima (NPRR)
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