Pantanal Matogrossense Research Articles

FOCOS DE CALOR E QUEIMADAS EM UNIDADES DE CONSERVAÇÃO FEDERAIS DO PANTANAL MATO-GROSSENSE NO PERÍODO DE 2016 – 2021

The Pantanal is one of the biomes that has suffered the most from burning, mainly due to its environmental characteristics. In view of this situation, this research sought to analyze the temporal space distribution of the sources of heat and recurrent fires in the Conservation Units Federal at the pantanal mato-grossense in the period 2016 to 2021 through Normalized Burn Ratio (NBR) and by the Forest Fires and Burns Program, made available by the National Institute for Space Research (INPE). Satellite images and analyzes of the NBR index were processed in a virtual platform (GEE) and a database was created, which were treated and generated two types of maps, the NBRs and the distribution of hotspots. The results showed that 2020 was the year with the highest occurrence of hotspots in the studied period, totaling 54,140 thousand hotspots inside of UCs. The UCs Mato-grossense Pantanal National Park, SESC-Pantanal Private Reserve of Natural Heritage Ecological Resort and the Taiamã Ecological Station, showed the highest area burned in the year 2021 throughout the study period. Compared to 2020, there was an increase in burned area in 2021 in the UCs, Taiamã Ecological Station, RPPN Reserve Jubran, RPPN Ecological Resort SESC-Pantanal, Mato-grossense Pantanal National Park. It has been shown that in UCs, RPPN Resort Farm Dorochê, RPPN Ecological Resort SESC-Pantanal, Mato-grossense Pantanal National Park the Low Severity, Low Moderate Severity and High Moderate Severity classes, which represent less dense vegetation, increased considerably from 2016 to 2021. The UCs that showed the highest burn were: RPPN Resort Farm Dorochê and Mato-grossense Pantanal National Park. The NBR in this study presented results that disagree with what actually happened in the UCs, showing that the period used in the study from July to October is not recommended, because the fires may not have occurred yet, however, it shows that for the following year when hot spots occurred, the NBR detects scars from the fires of the previous year.

Epidemiology of horse pythiosis in the Pantanal of Mato Grosso: Exploring the host-parasite-vector relationship

Horse pythiosis is considered an endemic disease in the Brazilian Pantanal region, causing devastating health and economic losses. This study aimed to enhance the understanding of pythiosis epidemiology, map the distribution of horse body lesions, and investigate the correlation between these lesions and warm body surface areas, potentially implicating hematophagous vectors in the disease's transmission. A prospective study was conducted on equids in the Pantanal Mato-grossense and adjacent areas from 2012 to 2022, with 112 horses and three mules diagnosed with pythiosis. Clinical and epidemiological data, lesions' photographic records, and healthy equids' thermal imaging were collected. Most pythiosis cases occurred between January and March, correlating with regional flood cycles. Most lesions were found on limbs and the ventral abdomen, with dark-colored horses exhibiting a higher frequency of lesions. Interestingly, the thermal mapping revealed that warm areas on a healthy horse's body overlapped significantly with lesion distribution – blood-sucking insects also prefer these areas. The results suggest that pythiosis lesions in horses correlate with warmer areas of the animal body, reinforcing the hypothesis of vector involvement in disease transmission. This study underscores the need for further observational research to fully understand the complex epidemiological dynamics of pythiosis in horses.

Genetic diversity and population structure of locally adapted Brazilian horse breeds assessed using genome-wide single nucleotide polymorphisms

Animals first introduced in Brazil with the discovery were submitted to various selective pressures over five centuries, developing adaptive traits specific to the hostile environments found in the country. A high quantity of genotypic information can be generated quickly and with high repeatability and reliability using genome-wide Single Nucleotide Polymorphism (SNP) panels. Blood samples from 285 horses belonging to eight Brazilian breeds (Baixadeiro, Lavradeiro, Marajoara, Puruca, Campeiro, Crioulo, Mangalarga Marchador and Pantaneiro) and two commercial breeds sampled in Brazil (Arabian and English Thoroughbred) were genotyped focusing on elucidating the genetic structure and composition within and among Brazilian horse breeds and some of their possible founders. Data from the GGP Equine BeadChip (GeneSeek® Genomic Profiler™ Equine, 65.157 SNPs) was used to assess basic diversity parameters, genetic distance (pairwise FST and Nei), Principal Component Analysis (PCA), Analysis of Molecular Variance (AMOVA) and population structure (ADMIXTURE). Results showed that Crioulo (few animals), Pantaneiro, Mangalarga Marchador, and Campeiro breeds possess distinct genetic bases from the others and each other. The Lavradeiro, Baixadeiro, Puruca, and Marajoara breeds have a shared genetic basis, hindering their differentiation. The results also reflected a geographic division of the Brazilian equine breeds, with those originally from the North and Northeast regions (Lavradeiro, Marajora, Puruca and Baixadeiro) grouped. On the other hand, animals from the South and Southeast regions (Crioulo, Campeiro and Mangalarga Marchador) were genetically closer although distinguished. The Pantaneiro breed originating from Pantanal Matogrossense in the Midwest region of Brazil, separated from all the others. Overall, high values of genetic variability and low values of FIS were observed for the Brazilian naturalized breeds. Both Arabian and English Thoroughbred sampled in Brazil presented a similar genetic variability to the Brazilian breeds but were genetically differentiated. This study aims to understand better the genetic variability and relation among Brazilian naturalized horse breeds and their possible origins. This information helps establish and maintain conservation nuclei and programs for each horse breed. Results found here can be used as a base for backup decisions regarding management to optimize conservation programs and other support sampling strategies for the National Animal Germplasm Program.

O surgimento do direito ambiental no Brasil, sua evolução e o cumprimento da agenda 2030

This article aims, as a general objective, to make a brief presentation on the evolution of Brazilian environmental law, its phases, and its current setback regarding sustainability. Although the Atlantic Rainforest, as well as the Amazon Forest, the Serra do Mar, the Pantanal Matogrossense, and the Coastal Zone have the status of national heritage, according to the Constitution of the Federative Republic of Brazil of 1988, these biomes have been losing space for deforestation, agriculture, and livestock, and currently only 12.4% of the original Atlantic Rainforest area is left in Brazil. As specific objectives of this article, it intends to analyze whether the commitments made by Brazil in the 2030 Agenda for Sustainable Development, an action plan adopted by the country and 192 other UN member states, have been fulfilled and also to make an analysis of the current Federal Senate Bill No. 168/2018. After the chronological survey of environmental legislation, it concludes that the Brazilian Environmental Legislation is currently not being effective in the protection of Brazilian biomes, meeting interests in deforestation, at the expense of Brazilian native species and in disagreement with the commitment made to Sustainability in the 2030 Agenda and the Sustainability principles presented in the Constitution of the Federative Republic of Brazil of 1988.

Diversity of insect galls from Mato Grosso State, Brazil: North Pantanal

Abstract: The Pantanal Biome occupies 20% of the Brazilian territory extending its distribution over two Brazilian States, Mato Grosso and Mato Grosso do Sul. This Biome is one of Brazil's poorly known regions concerning insect gall and their interactions with host plants. In this study, we characterized for the first time the gall morphology, identified host plants and the gall makers from an area of Brazilian wetlands from Mato Grosso State, known as Pantanal Matogrossense. We sampled Pantanal Biome areas in Poconé municipality, along the Transpantaneira Road, Mato Grosso State, Brazil, in two expeditions, July 2012 and January 2013, with a total effort of 2 hours. We characterized 91 morphotypes of insect galls in 54 host plant species; 28 gall makers in 24 host plant species; the richest host plant families are Fabaceae, Myrtaceae, and Sapindaceae. Psidium guineense Sw. is the super host species. This area in Pantanal Matogrossense is the second in the richness of gall morphotypes (N=91) and average morphotypes/plant species (1.7), comparing phytophysiognomies. Additionally, 15 plant species are new record as host in galler-host plant interaction in the world. This number represents 30% of the total of host plant species sampled in Poconé. This inventory is new knowledge to the Pantanal Matogrossense and representing a unique testimony of insect-plant interactions consumed by the unprecedented fire that occurred in Pantanal Biome in the dry season of 2020.

A apropriação da natureza e a reinvenção do capital nas áreas protegidas do Pantanal: o caso do Parque Nacional Otuquis (Bolívia), Parque Nacional do Pantanal Mato-Grossense (Brasil) e o Parque Nacional Rio Negro (Paraguai)

Este artigo visa identificar como as áreas protegidas localizadas no Pantanal (Bolívia, Brasil e Paraguai) têm sido apropriadas e reinventadas pelo capital. O objetivo principal é analisar como alguns grupos de interesse têm se apropriado destas áreas para implantar obras de infraestrutura, que em nada contribuem para a conservação. A partir da perspectiva de que, por trás do ideal conservacionista está embutido a apropriação da natureza e sua transformação, onde o capital se apropria dos recursos naturais na perspectiva de acumulação, optou-se por utilizar a concepção de natureza, enquanto uma produção social advinda das relações sociais. A metodologia utilizada foi uma combinação entre pesquisa bibliográfica, e a realização de pesquisas de campo. Portanto, esta análise surge com a possibilidade de identificar que tipo conservação está atrelada a essas áreas protegidas tendo em conta que o capital se apropria e se reinventa trazendo desdobramentos.

Morphological, physical and chemical attributes of the soil profile to the right margin of the Paraguay river, Baia da Campina, Cáceres (MT)

The fluvial dynamics corresponds to the natural changes of river channels that can influence the water energy, type and morphology of the gutter, geological structure and soil types. In this context, the type of soil present on the banks of the rivers stands out, which due to their morphological, physical and chemical characteristics, will offer greater or less resistance to marginal erosive processes. Whit this study, we aim to verify the contribution of soil morphological, physical and chemical attributes in the natural dynamics of the right bank of the Paraguay River. The studied area is located in the Pantanal Matogrossense, sub-region of Cáceres, and comprises the right bank of the Paraguay River, in the region of Baia da Campina, approximately 10 km away from the municipality of Cáceres, Mato Grosso, Brazil. We carry out morphological, granulometric and chemical description of the soil. The data were tabulated in a spreadsheet, being subsequently analyzed and discussed. The vegetation occurring in the study area is of the seasonal / cerrado and alluvial forests type, with the presence of low and semi-shrub vegetation. We classified the soil profile in the section studied as Fluvic Tb Endoeutrophic Neosol, presenting medium texture and, in general, high levels of sand and low levels of clay. The values referring to the effective cation exchange capacity (CTC) obtained in this study, were classified from low to very good, a characteristic that allows the existence of low and semi-shrubby vegetation, which contributes to the resistance to erosive processes, even that the soil has a low presenting resistance physical structure.

Salt-tolerant α-arabinofuranosidase from a new specie Aspergillus hortai CRM1919: Production in acid conditions, purification, characterization and application on xylan hydrolysis

Abstract Hemicelluloses are mainly branched heteropolysaccharides composed by xylose, arabinose, mannose, galactose, rhamnose and glucose. The main hemicellulose is xylan, a structure composed by xylose main chain branched with other monosaccharides or glucuronic and galacturonic acids. Among various hydrolytic enzymes acting on the degradation of xylan, α-L-arabinofuranosidases catalyze the hydrolysis of linkages between α-L-arabinofuranosides and the polysaccharide main chain. In this study, Aspergillus hortai strain CRM1919, isolated from soil surrounding saline and alkaline lagoons of the Nhecolândia region in Pantanal Matogrossense was investigated regarding the production of α-L-arabinofuranosidases. A. hortai produced α- l -arabinofuranosidase at high levels when cultivated in medium containing citrus pulp and orange peel at 1% (w/v) under static submerged cultures for 4 days and at pH 2.5 and 30 °C. The optimization steps increased 15-fold the enzymatic activity. The purified α- l -arabinofuranosidase was optimally active at pH of 4.0 and 60 °C, presenting half-lives of 265 and 230 min at 30 and 40 °C, respectively. High enzyme stability was observed after 24 h incubation at pH 5.0 and in presence of high concentration of NaCl in the reaction medium. The purified enzyme was mainly active against ρ-nitrophenyl-α- l -arabinofuranoside presenting the following kinetic parameters Km of 8.73 mmol/L, Vmax of 7.91 μmol/min.mg of protein and Kcat of 0.59/min. Hydrolysis of oat xylan performed in the presence of the purified α-arabinofuranosidase individually and in association with a purified xylanase made possible to verify the cooperation between these xylanolytic enzymes and the sequential action of each enzyme in the xylan structure hydrolysis.

Neotectonics as a structural control of the boundaries of the Pantanal Matogrossense Sub-Regions.

Characterized by fluvio-alluvial sedimentation processes, the heterogeneity in the Pantanal Basin allows its division in several sub-regions, which present natural characteristics of their own. It is possible to find in the literature different proposals to subdivide the Pantanal plain, which vary in total area and number of sub-regions. Each author uses specific criteria - mainly vegetation, soil and humidity - in his delimitation, but does not consider the tectonic aspects of the basin. In this sense, we intend to analyze three Pantanal delimitations from the literature and to relate them to the neotectonic context of the Pantanal plain by comparing the boundaries proposed in the delimitations to structural lineaments present in the basin. As a result, we observe that the comparison of the Pantanal boundaries with the lineaments shows a high compatibility between them, suggesting the influence of these structures in the development of the sub-regions.

Geotechnology as support for the management of conservation units in Brazil's Pantanal

The aim of this paper is to study temporal variations in vegetation indices as a tool for monitoring the integral protection conservation units (parks, reserves, and ecological stations) in the Brazilian Pantanal, giving support to environmental management actions in these areas. The study was carried out in five conservation units. Evaluated data, beside the Normalized Difference Vegetation Index (NDVI), included information on wildfires and deforestation. Analyses showed that the Taiamã Ecological Station, the Pantanal Matogrossense National Park, and the Encontro das Águas State Park presented high vegetation indices, showing their effectiveness as areas of environmental protection. Although this latter state park presented one fire hotspot in 2015, there was significant improvement in this park. The Guirá State Park and the Pantanal of Rio Negro State Park presented relatively low NDVI values when compared with other analysed areas. The aggravating factor was that in the Rio Negro park 36 fire hotspots occurred in 2007, demonstrating the need for more vigorous monitoring and management of this protected area.

Flood regime and water table determines tree distribution in a forest-savanna gradient in the Brazilian Pantanal.

This study aimed to recognized the preferential location of species of the tree sinusiae in response to a moisture gradient in Pantanal Matogrossense, Brazil. We established sampling plots of arboreal sinusiae along a soil moisture and flood gradient. Piezometers were installed, allowing monthly measurements of water table depth and flood height during one year. Detrended Correspondence Analysis, Gradient Direct Analysis, Multi-response Permutation Procedures and Indicator Species Analysis were performed to evaluate the effect of moisture gradient on tree distribution. The annual variation of water table is shallower and similar in Seasonally Flooded Forest and Termite Savanna, with increasing depths in Open Savanna, Savanna Forest and Dry Forest. Circa 64% of the species were characterized as having a preferential location in "terrestrial habitats normally not subjected to inundation", while 8% preferentially occur in "wet habitats". Lowest tree richness in flood-affected vegetation types is related to both present-day high climatic seasonality and Late Pleistocene dry paleoclimates in the Pantanal wetland. The tree distribution across different formations in the Pantanal shows a direct relationship with soil moisture gradient.

<b>Rhizobial diversity from stem and root nodules of <i>Discolobium</i> and <i>Aeschynomene</i>

Among the genera that exhibit stem nodulation, Aeschynomene and Discolobium are found in the Pantanal Mato-grossense (wetlands in the state of Mato Grosso, Brazil). Isolates obtained from the stem and root nodules of D. pulchellum, D. psoraleaefolium, D. leptophyllum and A. fluminensis were collected from various locations in the Pantanal de Pocone sub-region and phenotypically characterized and genotyped by restriction analysis of the 16S rDNA gene. Of the 282 isolates obtained from the stem and root nodules, 84.3% alkalized YMA media and 74.1% showed slow growth. No differences in either the phenotype or the genotype among the rhizobial populations isolated from the root or stem nodules of the species Discolobium and A. fluminensis were observed. Among the isolates obtained from D. pulchellum, there was a group that was not similar to any of the reference strains used, and most of the isolates analyzed by PCR-RFLP were similar to the genus Bradyrhizobium.

Length-weight relationships of 26 fish species from the streams of the upper section of the Paraguay River basin (Mato Grosso, Brazil)

Summary This study provides data on the length-weight relationships (LWR) for 26 tropical fish species collected in August 2010 (dry season) and May 2011 (wet season), and represents the first LWR references for these species in the small tributary streams flowing into the major rivers of the Pantanal Matogrossense, Brazil.

Juventude, sexualidade e saúde no universo rural: um olhar antropológico

O trabalho de cunho etnográfico tem como objetivo compreender, a partir do habitus, a aprendizagem e a vivência da sexualidade em jovens mulheres pertencentes às comunidades rurais do Pantanal Mato-grossense, no distrito de Joselândia – município de Barão de Melgaço. Foi desenvolvido de outubro/2007 a novembro/2008 e definiu-se como recorte para investigação mulheres na faixa etária de 14 a 20 anos que já vivenciaram experiências sexuais, resultando, ou não, na gravidez. Como recursos metodológicos foram utilizados: caderno de campo, observações diretas, fontes icnográficas e realizadas 32 entrevistas semiestruturadas. Caracterizar a vivência da sexualidade e da gravidez na juventude como um problema de saúde, enfatizados em estudos sobres as temáticas, denota desconsiderar os significados simbólicos sobre suas experiências no universo rural com especificidades culturais próprias. Os dados do estudo apontam que a vivência da sexualidade para jovens mulheres nesse lócus investigativo passa a se constituir um problema de saúde pela inexistência na localidade de ações de saúde que lhes garantam assistência, com resultados desastrosos para elas, que ficam susceptíveis a Doenças Sexualmente Transmissíveis (DST), à gravidez indesejada, sem atendimento pré-natal e ao parto.

Fishes from the Parque Nacional do Pantanal Matogrossense, upper Paraguai River basin, Brazil

The Pantanal Biosphere Reserve contains one of the highest concentration of animal species in the Neotropics, including about 300 fish species living in diverse environments associated with wetlands in the upper Paraguai River basin. This biome spans portions of Bolivia, Brazil and Paraguay and includes the Parque Nacional do Pantanal Matogrossense (PNPM), a region of the Pantanal which has been assigned as high conservation priority in Brazil. This study reports the results of an ichthyological survey within the PNPM, where samples were taken at 12 sites during the dry season in 2001, 2010 and 2011. We record 182 species representing three classes, 10 orders and 41 fish families. We report the first occurrence of the genus Anchoviella (order Clupeiformes), in the La Plata basin. This survey will provide information for future studies concerning conservation and management plans for the PNPM as well as for the Pantanal, which is one of the largest permanent wetland areas in the world and among the most unique and important South American biomes.

Fabaceae of the Rio São Francisco River sub-basin, Nova Marilândia, Mato Grosso, Brazil

The watershed of the São Francisco River is a large complex of headwaters of the Paraguay River, the main river of the Pantanal Matogrossense. Considering that Fabaceae are pointed out as the main family in floristic composition of various Brazilian biomes, however in some regions of Brazil is still little known upon the taxa, particularly in the Northern part of the Central-West, this study aimed to present a list of taxa occurring in the sub-basin of the São Francisco River, municipality of Nova Marilândia, State of Mato Grosso. For the taxa we give information on habit, vegetation, data on geographic distribution, potential use, successional strategy and dispersal syndrome, to subsidize habitat restoration projects. We recorded a total of 44 taxa, belonging to 25 genera. Inga stood out as the main genus in number of species. Among the identified taxa we found eight new records for the State of Mato Grosso: Chamaecrista brevicalyx (Benth.) H. S. Irwin & Barneby var. brevicalyx, Inga alba (Sw.) Willd., I. capitata Desv., I. heterophylla Willd., I. marginata Willd., I. nobilis Willd., Mimosa nitens Benth. and Ormosia coarctata Jacks. Vouchers are kept in the Herbarium UFMT.

Spatial, seasonal and ontogenetic changes in food resource use by a piscivore fish in two Pantanal lagoons, Brazil

We evaluated the factors that affect the food resource use by Plagioscion ternetzi using three approaches: spatial, seasonal, and ontogenetic changes. Fish were sampled between March 2000 and February 2001 and March 2003 and February 2004 in the Sinhá Mariana and Chacororé lagoons, wetlands of the Pantanal Matogrossense. Fish was the predominant food in the diet, but shrimps and insects have been also consumed. The diet of P. ternetzi was significantly different between lagoons, but no difference was detected between dry and flood periods. In Sinhá Mariana lagoon, the diet mainly consisted of Psectrogaster curviventris, in both periods. In the flood period in Chacororé lagoon, fish was the dominant food (especially Astyanax spp., Leporinus spp. and Schizodon borellii), and in dry, shrimp and Eigenmannia spp. The Spearman coefficient indicated no correlation between the abundance of caught fish species and their abundances in the diet of P. ternetzi in Sinhá Mariana lagoon, and a strong negative correlation at Chacororé lagoon, although some very consumed preys were numerically abundant in the environment. Despite the intake of insect and shrimp, P. ternetzi was piscivorous since immature stages. A correlation between each item and the size classes of P. ternetziwas tested by means of Pearson correlation that showed that the changes in the use of resources over ontogenetic development have been represented by increased intake of P. curviventris in Mariana lagoon, and S. borellii at Chacororé lagoon, accompanying the increase in the size of the predator. In this way, the results suggest that several factors can be involved in the use of food resources by P. ternezi, among them the abundance, the size and morphological characteristics of the prey.

Caracterização morfológica e mineralógica de solos em ambientes de cordilheira e campo de inundação no pantanal de Poconé, Mato Grosso

The current study was carried out in the sub-region of Pocone, a wetland area located in Mato Grosso State. The Gleyic Luvisol (LVg) and Dystric Gleysol (GLd) soils were considered for the study as significant representatives of two distinct environments existent in the Pantanal Mato-grossense, the cordillera and periodical flooding field, respectively. The objective was to understand the genesis of the soils from the characterization and study of their morphological and mineralogical properties. The results showed that the difference in moisture between the soils is related to the low difference of elevation from these environments, which affects the soils’ properties. In the Cordillera environment, the soil presents higher contents of free iron, whereas in the periodical flooding field, the soil presents higher contents of amorphous iron or low crystallinity. The extractions pointed out the presence of aluminum under polymeric form or low crystallinity. Among the morphological characteristics, the highest effect of the hydromorphism occurred in the soil of the periodical flooding field. The mineralogy of the clay fraction in both soils showed to be quite similar by constituting a variability of minerals, with emphasis to kaolinite (Ct) and minerals 2:1 such as illite (Il), hydroxy layered vermiculite (VHE) and, possibly smectite (Es) in the soil of the Cordillera environment. It was also confirmed the presence of quartz (Qz). The iron oxides considered predominant in both soils were the hematite (Hm), goethite (Gt) and lepidocrocyte (Lp).

Prevalência, distribuição geográfica e sazonal de protozoários e mixozoários parasitos de jaú (Zungaro jahu) no Pantanal Matogrossense

Estudo realizado no Pantanal Matogrossense, avaliou a prevalência, a distribuição geográfica e sazonal de protozoários e mixozoários parasitos de jaú (Zungaro jahu). Os peixes foram capturados no Sul do Pantanal, na região dos rios Aquidauana, Miranda e Paraguai, em 2001, 2002 e 2003, na região Central (Parque Nacional do Pantanal - PARNA Pantanal) em 2003, 2004, 2005 e 2008, e na região Norte (rios Cuiabá e Manso, no município de Nobres) em 2003, 2004 e 2005. Foi identificado Trichodina sp. parasitando pele e brânquias de jaú nas três regiões estudadas. Ocorrência de Epistylis sp. na pele e Cryptobia sp. nas brânquias foram restritas às coletas da região Central, enquanto Ichthyophthirius multifiliis foi identificado parasitando a pele nas três regiões estudadas. Também foi observada a ocorrência de mixozoários, Myxobolus cordeiroi parasitando vários órgãos e Henneguya sp. parasitando brânquias de jaú das três regiões estudadas.

Genetic variability in local Brazilian horse lines using microsatellite markers

Genetic variability at 11 microsatellite markers was analyzed in five naturalized/local Brazilian horse breeds or genetic groups. Blood samples were collected from 328 animals of the breeds Campeira (Santa Catarina State), Lavradeira (Roraima State), Pantaneira (Pantanal Mato-Grossense), Mangalarga Marchador (Minas Gerais State), as well as the genetic group Baixadeiro (Maranhão State), and the exotic breeds English Thoroughbred and Arab. We found significant genetic variability within evaluated microsatellite loci, with observed heterozygosis varying between 0.426 and 0.768 and polymorphism information content values of 0.751 to 0.914. All breeds showed high inbreeding coefficients and were not in Hardy-Weinberg equilibrium. The smallest genetic distance was seen between the Pantaneira and Arab breeds. The principal component analyzes and Bayesian approach demonstrated that the exotic breeds have had a significant influence on the genetic formation of the local breeds, with introgression of English Throroughbred in Pantaneira and Lavradeira, as well as genetic proximity between the Arab, Pantaneira and Mangalarga Marchador populations. This study shows the need to conserve traits acquired by naturalized horse breeds over centuries of natural selection in Brazil due to the genetic uniqueness of each group, suggesting a reduced gene flow between them. These results reinforce the need to include these herds in animal genetic resource conservation programs to maximize the genetic variability and conserve useful allele combinations.