Middle Araguaia River Research Articles

Mercury distribution in organisms, litter, and soils of the Middle Araguaia floodplain in Brazil.

Mercury (Hg) is a chemical element that, depending on its concentration, may become toxic to living organisms due to the ability of Hg to bioaccumulate in food chains. In this study, we collected samples of soil, litter, and organisms in the Middle Araguaia floodplain, Brazil. Total mercury (THg) concentrations in litter were significantly higher (p < 0.0001) than that in soil, ranging from 10.68 ± 0.55 to 48.94 ± 0.13 and 20.80 ± 1.07 to 55 .19 ± 1.59 ng g-1, respectively. Total mercury concentration levels in soil showed a linear, inversely proportional relationship with soil organic matter (SOM) contents and soil pH, consistent with the geochemical behavior of chemical elements in flooded environments. Ten orders of organisms were identified, and the average THg concentrations determined in their bodies were up to 20 times higher than those in soil and litter. We found a significant linear relationship between the levels of THg in litter and those found in soil organisms, thereby allowing the prediction of THg concentration levels in soil organisms through the analysis of litter at the sample units. The different dynamics and feeding habits of soil organisms and the concentration of THg in these organisms may be influenced by the river's course. This study provides evidence of the bioaccumulation of THg in soil organisms in the floodplain of the Middle Araguaia River, an important river basin in the Brazilian savanna.

Mercury Contamination as an Indicator of Fish Species' Trophic Position in the Middle Araguaia River, Brazil.

This study evaluates the use of mercury (Hg) concentrations in fish muscle tissue to determine a species' trophic position (TP) in its environment. A campaign conducted in 2019 along 375 km in the middle Araguaia River basin, Brazil, resulted in 239 organisms from 20 species collected. The highest total mercury (THg) concentrations were found in Pellonacastelnaeana (6.93 µg·g-1, wet weight) and in Triportheus elongatus (3.18 µg·g-1, wet weight), whose TPs were different according to the FishBase database. However, they occupied the same trophic level in this study. The intra-specific comparison showed a difference in Hg concentrations between individuals captured in distinct sites. The study of the biota-sediment accumulation factor (BSAF) showed that spatiality interferes with a species' TP. Statistical analyses revealed that when we used a predicted species' TP based on each individual's size, it explained 72% of the variability in THg concentration across all fish species. Multiple regression analysis confirmed that standard length and FishBase values are positively associated with THg (R2 = 0.943). These results point to Hg as a viable indicator of a fish species' TP since it reflects regional, biological, and environmental factors, as demonstrated here for the middle Araguaia River.

Sediment Mercury, Geomorphology and Land Use in the Middle Araguaia River Floodplain (Savanna Biome, Brazil)

In order to assess the influencing factors of the presence of mercury in a river within the Savanna biome (Cerrado), we surveyed total mercury (THg) in bottom sediment from 50 lakes along 750 km of the Middle Araguaia floodplain. The sampling sites included non-urban and urban surroundings over three distinct geomorphologies. We measured water physicochemical parameters at each site and tested statistically if land use nested within the geological formation influenced the THg concentration in bottom sediments and related water parameters. Multivariate results indicate that the interaction between geological groups and land use is statistically significant (p &lt; 0.05). Nested ANOVA and Tukey HSD tests confirmed that the geological formation with its nested land use influences the THg, pH, DO, conductivity, and TDS (p &lt; 0.05). THg was significantly lower in Quaternary terrains (p &lt; 0.05) and differed significantly between non-urban and urban areas in Neoproterozoic terrains (p = 0.02). The spatial projections of the THg eigenvector on the main axes with the scoring factors of the Neoproterozoic/Paleoproterozoic terrains, and urban/non-urban, confirmed the spatial correlations. These results indicate that the association of land use and geology could be the main driver of THg in the bottom sediments of lakes from the Middle Araguaia floodplain.

Geomorphic diversity of the middle Araguaia River, Brazil: A segment-scale classification to support river management

The complex mosaic of geomorphic units that characterizes the fluvial corridor of large rivers poses challenges to effectively describe and discriminate the landforms diversity, and is relationships with the hydrosedimentological dynamics and state of the system. Consequently, the classification of the diverse array of fluvial features into discrete segments can be a systematic and organized approach useful to sustain geomorphically-informed management strategies. Here we propose a methodological approach and characterize the geomorphic diversity of the middle Araguaia River by applying a classification of reaches into segments with a certain consistent level of morphological variability. A GIS framework developed for this purpose relied on the survey, analysis, and statistical treatment of morphological variables derived from remote sensing data. It allowed to differentiate 19 distinct reaches (R1-R19) that were further clustered into five major segments (SI-SV). We investigated the first-order controls of the fluvial style in each of the identified segments and found that changes in valley gradient influence in a major way the segments I, III, and IV, while the entrance of important tributaries and the nature of the valley floor are natural governing factors in segments II and V, respectively. The system exhibits a significant morphological diversity among segments, and it is strongly influenced by the late Holocene avulsion history of the river. Given the increasing pressure of human activities on the hydrological system, the present study can be of use to subsidize sustainable management plans aiming to safeguard the last large free-flowing river of the Cerrado biome, and our methodological proposal is valid for use in other large rivers worldwide.

Landscape features affect caiman body condition in the middle Araguaia River floodplain

AbstractLandscape modifications often undermine habitat suitability for species’ persistence, with initial effects observed through the physiological responses of individuals and populations. However, some landscape features can allow tolerant wildlife species to persist in human‐modified landscapes, but they are still overlooked. Across distinct agricultural landscapes, we assessed landscape features affecting the body condition (estimate through scaled mass index ‐ SMI) of Caiman crocodilus (Crocodylia, Alligatoridae) in human‐modified landscapes of the Araguaia floodplain, central Brazil. We used a spatial Bayesian model averaging approach to determine the effects of landscape attributes, ectoparasites, tail damage and severe body injuries on caiman body condition. We found that caimans had higher SMI in anthropogenic (ditches and artificial ponds) than natural habitats (lakes or rivers). Overall, caiman SMI was negatively associated with wetland cohesion (an aggregation and connectivity metric). Otherwise, landscape composition did not influence caiman SMI. Further, ectoparasites and body injuries did not affect SMI, whereas tail damage negatively affected SMI. Our findings underscore that caiman populations can adapt to artificial wetlands and irrigated rice fields, provided they incorporate natural and semi‐natural habitat patches that enhance environmental heterogeneity, prey availability, and waterbody availability and connectivity.

Priority areas and integrated actions for the conservation of Amazonian turtle populations historically over-exploited by humans

The definition of priority areas for conservation and integrated management actions are essential for the effective maintenance and recovery of natural populations, especially for species overexploited by humans. Amazonian chelonians are a food resource historically used by people, resulting in the decline of species populations and worsening the risk of local extinctions. In this paper, we establish priority areas and define integrated conservation actions for populations of three Amazonian chelonians most threatened by human consumption in Brazil (Podocnemis expansa, P. unifilis and P. sextuberculata). To do so, we used 15 prioritization criteria (ecological, logistical and socioeconomic) estimated with 30 years monitoring data in 15 areas by the Amazon Chelonian Program (in portugues Projeto Quelonios da Amazonia, PQA). Each criterion presented four levels of priority with scores increasing according to the relevance for conservation of chelonian populations. The sum of the scores obtained in each area of the PQA allowed a ranking and four categories of importance for conservation to be defined. We also analyzed the similarity of scores among areas of the PQA and among the prioritization criteria to evaluate the application of integrated conservation action strategies. The areas of PQA were classified as Extremely Important for Conservation (Rebio Trombetas River, Middle Xingu River, Middle Araguaia River, Upper Guaporé River), Very Highly Important for Conservation (Middle Purus River, Middle Juruá River, Crixás-Açu River Mouth, Sub-middle Tapajós River); Highly Important for Conservation (Sub-Middle Araguaia River, Amazonas River Mouth, Middle Mortes River); and Important for Conservation (Middle Guaporé River, Lower Branco River, Flechal River, Afuá River). The prioritization and similarity analyses can support the development of a national integrated plan of conservation actions to reduce the overexploitation of Amazon chelonian populations, according to the ecological, logistical and socioeconomic needs of each PQA area.

Modern and fossil pollen record from region of the middle Araguaia River floodplain, Tocantins State (Brazil)

The Araguaia river is one of the most important hydrographic basin in Brazil. Its drainage system reaches two dominant Brazilian biomes that are Amazon Rainforest and Brazilian Cerrado (savanna). This study was carried out in a zone of ecotone between rainforest and savanna formations, in the Middle Araguaia River basin, specifically at the floodplain of Javaés River its tributary by right margin, in the State of Tocantins. The goal of this present study was to provide information about the vegetational succession in this forest-savanna ecotone area, in order to contribute to the understanding of this landscape dynamics. For this reason, a sedimentary core collected from a lake (Lago da Mata Verde) was submitted to palynological and radiocarbon dating analyses. The results showed that during the last 400 years this site was bordered by forest reflecting a wet climate with some increase of the flooded margins in the present day. The modern pollen rain and local vegetation data supported in the interpretation of the fossil pollen results. Our findings are according to other studies carried out in the similar ecotone zones and floodplains in Amazonian regions during the Late Holocene.Keywords. Lacustrine sediments, Late Holocene, pollen analysis. Resumo. O rio Araguaia constitui uma das mais importantes bacias hidrográficas brasileiras. Seu sistema de drenagem atravessa dois dominantes biomas brasileiros a saber o bioma Amazônico e o Cerrado brasileiro (savanas). Este estudo, foi realizado em uma zona de ecótono entre as formações de floresta tropical e savana, na bacia do Médio Rio Araguaia, especificamente na planície de inundação do rio Javaés, seu tributário pela margem direita, no estado do Tocantins. O objetivo deste estudo foi fornecer informações sobre a sucessão vegetal nesta área de ecótono floresta-savana, visando contribuir para o entendimento da dinâmica desta paisagem. Dessa forma, um testemunho sedimentar coletado no Lago da Mata Verde foi submetido às análises palinológicas e de datação radiocarbônica. Os resultados mostraram que durante os últimos 400 anos este ambiente foi cercado por floresta refletindo um clima úmido, com um ligeiro aumento de margens inundadas nos dias atuais. Os dados de chuva polínica atual e de vegetação local fundamentaram a interpretação dos resultados palinológicos fósseis. Os resultados obtidos são similares a outros estudos realizados em outras áreas de ecótonos e planícies de inundação em regiões da Amazônia durante o Holoceno Tardio.Palavras-chave. Sedimentos lacustres, Holoceno Tardio, análises palinológicas

CONSERVATION OF THE ORINOCO GOOSE (NEOCHEN JUBATA) IN THE MIDDLE ARAGUAIA RIVER, TOCANTINS, BRAZIL.

The Orinoco goose, (Neochen jubata) is a grazing herbivore of open habitats that was once widely distributed in tropical South America. Centuries of overhunting and habitat loss have reduced it to widely scattered remnant populations; it is categorized as Near Threatened globally. Within the Cerrado biome, the Middle Araguaia River houses the largest remnant population. In August 2017, a study was started to assess the situation of the Orinoco Goose in the regions of Araguaia National Park, Cantão State Park, and adjacent rice fields. We conducted counts from an aerial census (a 700 km transect), monthly boat censuses (40 km) and land censuses in rice plantations. The aircraft census counted 367 individuals in August 2017, while monthly monitoring of a stretch of the lower Javaés River over more than two years showed a seasonal population variation associated with the flood regime, with the species virtually disappearing during the flood period between January and April when river beaches are submerged. During this period, large flocks of about 1,000 Orinoco Geese were discovered not far away, concentrated in small stretches of rice plantation agro-systems in the region. This behavioral seasonal concentration makes the species susceptible to poisoning and epizootic diseases. The findings suggest the need to re-categorize the Orinoco Goose population of the Middle Araguaia River as “Threatened” for the State of Tocantins due to the decline observed in the last 10 years, the maximum estimated population size, and the significant seasonal concentrations in a restricted area. At the same time, it is necessary to develop an action plan for its conservation in the surroundings of Ilha do Bananal, and throughout Brazil, where its threat status must be reviewed.

Regionalization of reference streamflows for the Araguaia River basin in Brazil

Hydraulic projects and water management require reliable hydrological data. The Araguaia-Tocantins River basin, in addition to agricultural use, has great potential for hydroelectric exploitation. However, the streamflow monitoring network in the Araguaia River basin is composed of only a few stations, resulting in a lack of hydrological data. The regionalization of the reference streamflows is a technique that can help circumvent this lack of data, enabling the estimation of streamflows from easily obtainable explanatory variables. In this context, the objective of this study was to develop regional functions for the maximum streamflow (Qmax) applicable to different Return Periods (RP), the long-term mean streamflow (Qmlt) and the 95% streamflow permanence (Q95) of the upper and middle Araguaia River sub-basins. The dimensionless streamflow methodology was adopted with the drainage area as an explanatory variable. The tested regressive models were the linear, potential and quotient models. Leave-one-out cross-validation was used to assess the quality of the regional models. Ten statistical distributions of 2 to 5 parameters were used. (i) Satisfactory results were obtained for all reference streamflows. (ii) The cross-validation technique proved to be essential for the selection of the most robust model. (iii) The quotient model was shown to be superior to the potential linear model in most cases.

A new miniature cryptic species of the seasonal killifish genus Spectrolebias from the Tocantins River basin, central Brazil (Cyprinodontiformes, Aplocheilidae)

The miniature seasonal killifishSpectrolebiascostae, first described for the middle Araguaia River basin, has been also recorded from two areas in the middle Tocantins River basin, from where male specimens exhibit some differences in their colour pattern. Analyses directed to species delineation (GMYC and bPTP), using a fragment of the mitochondrial gene COI, strongly support two species,S.costaefrom the Araguaia River basin and a new species from the Tocantins River basin.Spectrolebiasgracilissp. n.is described on the basis of specimens collected from two localities separated by about 530 km, Canabrava River floodplains near Alvorada do Tocantins and Tocantins River floodplains near Palmeirante. Field inventories were unsuccessful in finding additional populations in the region, which is attributed to the high environmental degradation, including several large dams that have permanently inundated typical killifish habitats.Spectrolebiasgracilisis member of a clade also includingS.costae,S.inaequipinnatus, andS.semiocellatus, diagnosed by having the dorsal and anal fins in males with iridescent dots restricted to their basal portion, caudal fin in males hyaline, and caudal-fin base with two pairs of neuromasts. Within this clade, a single miniaturisation event is supported for the most recent common ancestor of the subclade comprisingS.costaeandS.gracilis, which differ from other congeners by reaching only about 20 mm standard length as maximum adult size.

Assessing the spatial variation of functional diversity estimates based on dendrograms in phytoplankton communities

ABSTRACT Variation in phytoplankton functional diversity is partioned and mapped using several indices and linkage methods based on dendrograms. The relationships between diversity metrics and major environmental predictors, including zooplankton density, were assessed in 29 phytoplankton communities of floodplain lakes distributed along the Middle Araguaia River in central Brazil. The dendrogram-based functional diversity indices were Functional Group Richness, Functional Diversity, Mean Pairwise Distance and Mean Nearest Taxon Distance, whereas seven different hierarchical agglomerative linkage methods we used. The performance of indices were compared using ANOVA and their spatial variation in response to major environmental predictors evaluated. The results indicate that variation in functional diversity values is primarily a product of the type of index chosen. This variation was statistically significant in 90 % of the floodplain lakes studied; however, a spatial pattern of variation in index values along the river was not detected. Furthermore, environmental constraints, including zooplankton density, were weak predictors of functional diversity indices. Therefore, the mathematical characteristics of indices are of primary importance in explaining variation among functional diversity values.

Sampling sufficiency for estimating zooplankton diversity in neotropical floodplain lakes

AbstractThis study focuses on determining how many samples are needed to effectively assess the species richness of a community. Zooplankton samples at 40 sampling sites distributed among four lakes in the floodplain of the middle Araguaia River (Central‐West region of Brazil) were evaluated to determine the effect of the accumulation of collecting points by lake on species richness estimates. The results indicated the zooplankton community has high spatial heterogeneity. Thus, using a single sampling unit per lake would not be sufficient to accurately estimate their diversity (i.e. the zooplankton composition in these cases would be represented mainly by abundant species). Sampling designs that include a minimum of seven sampling sites in each lake are needed to record 70% of the total species richness. It is recommended, therefore, that researchers use a larger number of sampling sites per lake or, alternatively, that the water obtained and filtered through plankton nets is extracted from a wide area and in different lake compartments, rather than from a single site.

Flooding hydrology and peak discharge attenuation along the middle Araguaia River in central Brazil

The Araguaia River in central Brazil is the largest river draining the Brazilian savanna. Located in a tropical wet-dry climate, the middle Araguaia River has an extensive and complex alluvial floodplain composed of a mosaic of geomorphologic units, dense alluvial forest, and many floodplain lakes. The Araguaia River is not currently dammed, and thus it provides an opportunity to analyze flooding hydrology in a relatively un-altered tropical system. Using average daily discharge measurements from 1975 to 2011, we analyze patterns of peak discharge attenuation (defined as the reduction in absolute peak discharge in m3s−1). We link peak discharge attenuation to bankfull discharge, explore whether peak discharge attenuation results in increased base level flows in the dry season following peak discharge, and use a simplified short-term water budget to determine whether peak discharge attenuation results in the loss of discharge from the channel over the flooding season (November to May). In addition, we explore other potential factors causing peak discharge attenuation, including surface water connectivity between the channel and floodplain lakes and floodplain lake area change between the dry season and the wet season. Although fluvial connectivity between the main channel and the floodplains starts before bankfull stage, we find that large peak discharge attenuation (up to 30% reduction in peak discharge) in the middle Araguaia usually occurs when the river rises above bankfull discharge. The river flow that is lost to the floodplain and floodplain lakes when peak discharge attenuation occurs usually returns to the channel by the end of the flooding season. However, the odds of increased baseflows in the dry season after flooding seasons with peak discharge attenuation are higher compared to flooding seasons without peak discharge attenuation for one of the studied reaches. Some types of floodplain lakes greatly increase in area from the dry season to the wet season, and many floodplain lakes become connected via surface water in the wet season. We have not found similar examples of peak attenuation in this type of tropical wet-dry floodplain system, indicating that the middle Araguaia River may be a unique system or that further research is needed.

Relationships among vegetation, geomorphology and hydrology in the Bananal Island tropical wetlands, Araguaia River basin, Central Brazil

The Bananal Plain spreading on the Middle Araguaia River basin in Central Brazil at the Cerrado–Amazonia ecotone is a unique system that sustains the largest seasonal wetlands of the Cerrado biome. The huge Bananal Plain is an intracratonic sedimentary basin filled with Pleistocene sediments of the Araguaia formation. Covering approximately two million hectares, the Bananal Island is a major geomorphologic feature of the Bananal plain. Fieldwork and the analysis of a temporal series of MODIS–VI and Landsat ETM images allowed us to discriminate Cerrado phyto-physiognomies on the Bananal Island. Maps of vegetation and geomorphologic units were created, and from the correlation between landforms and vegetation types we identified morpho-vegetation units.Our approach allowed us to postulate that Pleistocene landforms strongly influence, if not dominate, the distribution of vegetation units.For example, the distribution of current gallery forest is not only controlled by active floodplains, but also by alluvial belts abandoned by avulsion. Additionally, arboreal Cerrado vegetation is supported by laterite developed on the sediments of the Araguaia Formation. Some of these inactive landforms are in part modified by the present day geomorphologic processes and colonized by successional vegetation that varies from alluvial forest to Cerrado.Characterized by a very flat landscape with a hindered drainage, the muddy sediments of the Araguaia Formation and the high seasonal rainfall favor the development of regional seasonal wetlands.The Bananal plain is a key area for understanding the Quaternary climatic and biogeographic changes in tropical South America. The control exerted by relict Quaternary landforms on the current vegetation units demonstrates the strong links between geomorphologic aspects of the landscape and ecological patterns. This multidisciplinary approach provides a better understanding of the biogeographic patterns in the Cerrado–Amazon ecotone, which is useful for identifying and designing areas for conservation.

Zoneamento dos lagos prioritários para conservação e manejo do peixe Pirarucu na reserva extrativista Lago do Cedro, rio Araguaia, Aruanã – GO

The Lago do Cedro Extractive Reserve is located on the right bank of the middle Araguaia River course, five miles north of the Aruana city, State of Goias, Brazil.It is estimated that approximately 52% of the area of the reserve is located in the floodplains of the Araguaia River. The floodplains of the Araguaia River are considered one of the largest wetland areas of the Brazilian Cerrado and have high ecological value. The high human pressure on the wetland areas led to the creation of the Lago do Cedro Extractive Reserve in 2006. Among other factors, this Reserve has the purpose of reducing human pressure on these areas to allow sustainable regional economic development. This article aims to evaluate morphological and morphometric characteristics of the lakes found in the Reserve in order to determine the lakes that should be conserved for preservation of the Pirarucu fish. Result was the zoning of the lakes located in the floodplain of the Araguaia River in the Reserve that was divided into two zones: Preservation Zone and Exploration Zone of the Pirarucu fish.

Avaliação do transporte de carga sedimentar no médio rio Araguaia

The study estimates the bed load sediment in the middle Araguaia River, through the height and dunes daily displacement. The studied region is located between the mouth of the Crixás-Açú River and the Bananal Island, Goiás. The dunes migrated at the rate of 7 m/day, the average water velocity was 1.25 m/sec, corresponding to a total transport of 2195.60 ton of bed load/day. Two methods were compared in order to verify possible sources of error, the Van Rijn one showed a difference of 1414 tons less then the Struckrath method, difference of 0,06% in the estimated bed load between both methods. Results were compared with the bed load of the Araguaia River in the region of Aruanã.

LISTAGEM FLORÍSTICA DAS CYPERACEAE HIDRÓFILAS DA REGIÃO DO ALTO E MÉDIO RIO ARAGUAIA, GOIÁS, MATO GROSSO E TOCANTINS, BRASIL – PARTE I

This work provides the first part of the checklist of hydrophilous Cyperaceae from the upper and middle Araguaia river, located in the states of Goi&aacute;s, Mato Grosso and Tocantins, in Brazil. The taxa were identified based on the literature and by comparison with the following herbarium collections: UEC, UFG, R and RB. So far, 10 genera and 29 species have been identified for the studied area. The geographic distribution and a list of the specimens examined are presented.

Phytoplankton diversity (alpha, beta, and gamma) from the Araguaia River tropical floodplain lakes (central Brazil)

Alpha, beta and gamma are three components of species diversity. Knowing these attributes in floodplain lake phytoplankton communities is vital when selecting conservation areas. Species diversity is commonly used with other taxonomic groups, but rarely with phytoplankton. We compared the number of phytoplankton species (alpha diversity) from 21 Middle Araguaia River floodplain lakes in the 2000 and 2001 rainy and dry seasons. From these samples we estimated complete survey species richness (gamma diversity), quantified differences in species composition between lakes (beta diversity) and assessed the influence of abiotic variables on beta diversity. We recorded a total of 577 taxa. The Sjack1 estimator indicated that 62.31% of taxa were sampled in the 2000 rainy and 67.65% dry seasons, and 68.36% in the 2001 rainy and 73.5% dry seasons. In almost all seasons, alpha diversity negatively correlated with latitude. Beta diversity (β-1) was higher in high water periods, especially in 2000. This may have been caused by isolated heavy rainfall, which would have increased environmental heterogeneity and raised beta diversity. DCA showed differences in phytoplankton composition between rainy and dry seasons in 2000 and 2001, reflecting the influence of flood pulses on phytoplankton composition. The Mantel test indicated spatial distribution patterns where geographically more distant lakes had less-similar phytoplankton communities.

Chromosomal characterization of the bonytongue Arapaima gigas (Osteoglossiformes: Arapaimidae)

The mitotic chromosomes of the pirarucu Arapaima gigas inhabiting the middle Araguaia River and collected in the municipality of Araguaiana (MT, Brazil) were studied. The chromosomes were analyzed through Giemsa staining, C-banding, Ag-NOR staining and in situ hybridization using an 18S rRNA gene probe. The karyotype had 2n=56 comprising 14 biarmed and 14 uniarmed chromosome pairs in both sexes. No cytologically distinguishable sex chromosome was identified. A single NOR-bearing chromosome pair was detected by Ag-NOR staining and confirmed by 18S rDNA- FISH. Faint constitutive heterochromatin was C-banded in the centromeric region of some chromosomes.

Alismatales from the upper and middle Araguaia river basin (Brazil)

The present study deals with a survey of the order Alismatales (except Araceae) in the upper and middle Araguaia River region located between the states of Mato Grosso and Goias, Brazil. Field expeditions were carried out during the rainy and dry seasons. The route covered approximately 2,000 km and 41 aquatic environments were visited. Thirteen taxa, representing the families Alismataceae (nine), Hydrocharitaceae (three) and Najadaceae (one) were identified. Keys for the identification of families and species in field, brief diagnoses, schematic illustrations and relevant comments were elaborated based on field observations as well as on the analysis of the specimens collected.