CECAV
URI permanente desta comunidadehttps://bdc.icmbio.gov.br/handle/cecav/1
Centro Nacional de Pesquisa e Conservação de Cavernas
Navegar
11 resultados
Resultados da Pesquisa
Item Global distribution of carbonate rocks and karst water resources(2021-04-21) Goldscheider, Nico; Chen, Zhao; S. Auler, Augusto; Bakalowicz, Michel; Broda, Stefan; Drew, David; Hartmann, Jens; Jiang, Guanghui; Moosdorf, Nils; Stevanovic, Zoran; Veni, GeorgeKarst regions offer a variety of natural resources such as freshwater and biodiversity, and many cultural resources. The World Karst Aquifer Map (WOKAM) is the first detailed and complete global geodatabase concerning the distribution of karstifiable rocks (carbonates and evaporites) representing potential karst aquifers. This study presents a statistical evaluation of WOKAM, focusing entirely on karst in carbonate rocks and addressing four main aspects: (1) global occurrence and geographic distribution of karst; (2) karst in various topographic settings and coastal areas; (3) karst in different climatic zones; and (4) populations living on karst. According to the analysis, 15.2% of the global ice-free continental surface is characterized by the presence of karstifiable carbonate rock. The largest percentage is in Europe (21.8%); the largest absolute area occurs in Asia (8.35 million km2). Globally, 31.1% of all surface exposures of carbonate rocks occur in plains, 28.1% in hills and 40.8% in mountains, and 151,400 km or 15.7% of marine coastlines are characterized by carbonate rocks. About 34.2% of all carbonate rocks occur in arid climates, followed by 28.2% in cold and 15.9% in temperate climates, whereas only 13.1 and 8.6% occur in tropical and polar climates, respectively. Globally, 1.18 billion people (16.5% of the global population) live on karst. The highest absolute number occurs in Asia (661.7 million), whereas the highest percentages are in Europe (25.3%) and North America (23.5%). These results demonstrate the global importance of karst and serve as a basis for further research and international water management strategies.Item Priority caves for biodiversity conservation in a key karst area of Brazil: comparing the applicability of cave conservation indices(2018-05-09) Rabelo, Lucas Mendes; Souza‑Silva, Marconi; Ferreira, Rodrigo LopesLandscapes in tropical regions have been greatly altered by human activities, as a product of growing demands for mineral and agricultural production, as well as those related to the generation of energy (e.g., hydroelectric, wind). In this scenario, caves have suffered several impacts, sometimes irreversible, as they are generally associated with rocks of high economic value and are closely related to epigean systems. Several indices have been proposed to guide conservation policies for the world’s speleological heritage, although few of them consider cave biodiversity as a criterion. To address this knowledge gap, we tested the applicability of four newly proposed indices to assist researchers and policy-makers select priority areas for global cave biodiversity conservation. To compare indices, we used data from 48 caves of the largest carbonate region of South America (Bambui geological group), all found within the Cerrado, a global biodiversity hotspot. Each of the four indices considered cave biodiversity as a criterion, although only three adequately evaluated this attribute. Based on results of Simões index and CCPi, which were the most appropriate in relation to indicate priority caves for biodiversity conserva-tion in regions where the fauna and its distribution are not fully known, 15 of the 48 caves were identified as conservation priorities.- Epigean and hypogean drivers of Neotropical subterranean communities(2020-10-29) Rabelo, Lucas Mendes; Souza-Silva, Marconi; Ferreira, Rodrigo LopesIn addition to cave size and other subterranean habitat characteristics, cave entrances are important structurers of neotropical cave communities. However, little is known about the epigean ecosystems factors that might dictate the influence of entrances and the relationship among surface and cave communities, as entrance re-gions are ecotonal zones between the epigean and hypogean ecosystems. We aimed to assess the influence of epigean and hypogean factors as potential drivers of inver-tebrate species richness in Neotropical caves as well as the influence of the regional pool of invertebrate diversity on cave invertebrate diversity.
- Assessment of a semi-automatic spatial analysis method to identify and map sinkholes in the Carste Lagoa Santa environmental protection unit, Brazil(2021-01-21) de Castro Tayer, Thiaggo; Horta Rodrigues, Paulo CésarSatellite imaging combined with geoprocessing routines is a promising alternative to establish a viable mapping model of specific landscape features and soil use, with high precision, fast results, and low operational costs. The present study examines the employment of a digital elevation model (DEM) combined with geoprocessing techniques for identifying closed depressions in karst landscapes with the objective of mapping potential sinkholes and uvalas within the limits of the Carste Lagoa Santa Environmental Protection Unit, located in the state of Minas Gerais, Brazil. The proposed method consists of using geoprocessing routines combined with DEMs, topographic analysis, individual points of elevation, and mathematical operations between rasters. To accomplish that, SRTM (Shuttle Radar Topographic Mission) data/images were used to extract contour lines and individual elevation points to identify depressions, delimit their edges, and obtain morphometric data referring to the area, perimeter, and their circularity index. The results were satisfactory, allowing the detection of 1076 depressions within the study area. The results were also analyzed for special morphological cases and circularity patterns and compared with a previous study. Field campaigns allowed the partial validation of the method, which proved to be a viable alternative for preliminary and extensive scale mapping of these important karst recharge features.
- An approach to map karst groundwater potentiality in an urban area, Sete Lagoas, Brazil(2020-09-28) Magnabosco, Rafael; Galvão, Paulo; de Carvalho, Ana MacielDue to complex hydrogeological contexts, mapping groundwater potential zones in karst regions is a difficult task. This study was conducted on a karst terrain in Sete Lagoas, Brazil, where rapid urban growth without adequate water resources management resulted in the drilling of unproductive wells and possible aquifer over-exploitation due to the concentration of wells. The objective was to develop a method for mapping groundwater potentiality for karst aquifers, serving as water resources management tool, based on 3D geological modelling, field work and pumping test data, remote sensing, geophysics analysis and production of thematic maps, resulting in the hydrogeological conceptual model. The groundwater potentiality map showed that most potential zones are on the central area, limited by grabens, where limestones are in contact with unconsolidated sediments, on areas with higher density of morphostructural and geophysical lineaments, mainly in east–west and north–east directions, near karst surface features, on thicker karstified zones, with higher recharge rates.
- Inside or out? Cave size and landscape effects on cave-roosting bat assemblages in Brazilian Caatinga caves(2020-04-08) Carlos Vargas-Mena, Juan; Cordero-Schmidt, Eugenia; Rodriguez-Herrera, Bernal; A. Medellín, Rodrigo; de Medeiros Bento, Diego; M. Venticinque, Eduardo; Jorge OrtegaCave bats have an intimate association with their roosts. Size, structural heterogeneity, and microclimatic conditions are traits of caves known to affect the structure of these assemblages. The effects of the natural and anthropogenic landscape factors around caves on the structure of these assemblages are poorly known, especially in areas with large cave clusters. We assessed the effects of cave size and surrounding landscape attributes on the richness and species composition of cave-roosting bats in 13 caves distributed in two landscapes with large cave clusters in Caatinga dry forests, Brazil. In a 1-km buffer around caves, we obtained 13 internal cave and external landscape variables. Candidate univariate models using generalized linear models were constructed and the Akaike information criterion was used for model selection. The cave size model explained richness and variance in the species composition; larger caves tended to have greater richness and assemblage composition varied depending on the cave size, hence affecting the occurrence of certain species, some of conservation concern (Natalus macrourus, Furipterus horrens). The cave connectivity model affected only the richness; caves located in denser cave clusters had higher richness likely attributed to movement of bats among caves by a more diverse array of species. Both environmental and anthropic variables affected species composition, but differently depending of the landscape context of cave location (protected versus nonprotected area). The extent these landscape variables affected the species composition was due to species-specific responses, and observed in the mean colony sizes of the species shared between the cave systems. All the landscape variables that we tested affected the structuring process of cave-roosting bats assemblages, and evidences that variables found in disturbed karstic landscapes also affect the structure of the assemblage (e.g., large colonies of vampire bats). However, the ubiquitous effect of cave size on both richness and species composition reinforces the critical importance of the roost in the life of these flying mammals.
Item Assessment of a semi-automatic spatial analysis method to identify and map sinkholes in the Carste Lagoa Santa environmental protection unit, Brazil(2021-01-21) Tayer, Thiaggo de Castro; Rodrigues, Paulo César HortaSatellite imaging combined with geoprocessing routines is a promising alternative to establish a viable mapping model of specific landscape features and soil use, with high precision, fast results, and low operational costs. The present study examines the employment of a digital elevation model (DEM) combined with geoprocessing techniques for identifying closed depressions in karst landscapes with the objective of mapping potential sinkholes and uvalas within the limits of the Carste Lagoa Santa Environmental Protection Unit, located in the state of Minas Gerais, Brazil. The proposed method consists of using geoprocessing routines combined with DEMs, topographic analysis, individual points of elevation, and mathematical operations between rasters. To accomplish that, SRTM (Shuttle Radar Topographic Mission) data/images were used to extract contour lines and individual elevation points to identify depressions, delimit their edges, and obtain morphometric data referring to the area, perimeter, and their circularity index. The results were satisfactory, allowing the detection of 1076 depressions within the study area. The results were also analyzed for special morphological cases and circularity patterns and compared with a previous study. Field campaigns allowed the partial validation of the method, which proved to be a viable alternative for preliminary and extensive scale mapping of these important karst recharge features.Item Quaternary depositional facies in cave entrances and their relation to landscape evolution: The example of Cuvieri Cave, eastern Brazil(Catena, 2017) Martim, Paulo M. Haddad; Hubbe, Alex; Giannini, Paulo C.F; Auler, Augusto S; Piló, Luís B; Hubbe, Mark; Mayer, Elver; Wang, Xianfeng; Cheng, Hai; Edwards, R. Lawrence; Neves, Walter AUm estudo na Caverna de Cuvieri permitiu novos conhecimentos sobre a dinâmica e evolução de tipos de facies sedimentares e sua relação com a paisagem próxima.Item Environmental and legal aspects of karst areas. Lamoreaux, P.E.(Environmental Geology, 1997) Lamoreaux, P. E.; Powell, W. J.; LeGrand, H.E.implicações regulatórias Karst para configurações cárstica subsidência de proteção ambientalItem Habitat and Population Data of Troglobitic Armored Cave Catfish, Ancistrus Cryptophthalmus Reis, 1987, from Central Brazil (Siluriformes: Loricariidae)(Environmental Biology of Fishes, 2001) Trajano, Eleonora