CECAV
URI permanente desta comunidadehttps://bdc.icmbio.gov.br/handle/cecav/1
Centro Nacional de Pesquisa e Conservação de Cavernas
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6 resultados
Resultados da Pesquisa
Item The role of turnover in structuring subterranean aquatic communities in Southeastern Brazil(2024) Zepon, Tamires; Bichuette, Maria ElinaSimilarly to other animal communities, the diversity of subterranean aquatic fauna is influenced by several factors and processes, such as habitat fragmentation, dispersion, environmental heterogeneity, and physical and chemical water characteristics. Here, we studied cave aquatic communities of the Alto Ribeira hydrographic basin, regarding troglobitic and non-troglobitic species, located in a single karst area to evaluate the influence of sub-basins in fauna differentiation. We investigated how abiotic variables (flow, electrical conductivity, temperature, pH, and substrate) influence the fauna composition and the contribution of beta diversity components (nestedness and turnover) in explaining communities’ dissimilarities. Fauna composition differed between sub-basins, as most species did not co-occur in different caves. Caves with higher flow and substrate diversity were the richest. In addition, each cave community was influenced by a unique set of abiotic variables. Dissimilarity among caves was mainly explained by turnover, and our findings suggest the restricted species distribution could be due to ecological (e.g., limited dispersion capacity, tolerance to abiotic variables), hydrogeological (e.g., dispersion barriers, isolation of sub-basins), and historical (e.g.,colonization, paleoclimatic events) factors and processes. Therefore, different elements are responsible for determining the composition of cave aquatic communities in different sub-basins, reflecting the variability within a single karst area.Item A new species of the troglobitic genus Spelaeogammarus da Silva Brum, 1975 (Amphipoda: Artesiidae) from a cave in the Brazilian semi-arid region, with new records of its congener, Spelaeogammarus spinilacertus Koenemann and Holsinger, 2000(2022-06-17) Bueno, Alessandra Angélica de Pádua; Bichuette, Maria Elina; Zepon, Tamires; Penoni, Ludmila RochaWe propose a new species of the troglobitic genus Spelaeogammarus da Silva Brum, 1975, with data on its distribution, ecology, aspects of behavior, and conservation status. Spelaeogammarusginae sp. nov. occurs in a single cave in the Serra do Ramalho karst area, of the northeastern Brazilian semi-arid region. We also provide new data on the distribution and conservation status of its congener, Spelaeogammarus spinilacertus Koenemann and Holsinger, 2000 that occurs in the upper phreatic aquifer inside caves from Chapada Diamantina domain. Both species occur in caves in the state of Bahia, northeastern Brazil.Item Under the surface: what we know about the threats to subterranean fishes in Brazil(2021-03) Bichuette, Maria Elina; Eduardo Gallão, JonasThe present work brings information on threats to the subterranean fishes in Brazil. Currently, at least 36 species are known, 22 of which are already formally described. Endemism is the rule for most of them. Regarding their conservation, these fishes are in general considered threatened: and most of the already formally described species are included in national lists of threatened fauna, and only four of them are included in the global list of the IUCN. Regarding habitats, Brazilian subterranean fishes occur in alluvial sediments (part of the hyporheic zone), shallow base-level streams, flooded caves, lakes in the water table, upper vadose tributaries, and epikarst aquifers. We detected 11 main threats, mainly related to agriculture, pasture, and hydroelectric plans, but unmanaged tourism and pollution are also significant threats. Two threats affect a high number of species (physical change of the habitat and food restriction). The river basins with the higher number of identified threats are the upper Tocantins (eight) followed by the upper Paraguaçu (six). Effective proposals to protect this neglected component of the Brazilian biodiversity are still scarce, such as monitoring projects and their function in the subterranean communities, besides education projects aiming to develop public awareness.- New records of the troglobitic Hyalella veredae Cardoso & Bueno, 2014 (Crustacea, Amphipoda, Hyalellidae) from Minas Gerais caves, southeast Brazil, with notes on its natural history(2021-01-18) Zepon, Tamires; Resende, Leonardo; Bueno, Alessandra Angélica de Pádua ; Bichuette, Maria ElinaSince its description, the troglobitic amphipod Hyalella veredae Cardoso & Bueno, 2014 has been recorded only in its type locality, Vereda da Palha cave, in southeastern Brazil. We report this species from three other caves in the region, expanding its distribution by at least 20 km². Inter- and intra-population variability in eye size was observed. Two caves had larger populations, probably due to the presence of biofilm. The species was classified as Critically Endangered due to its restricted area of occurrence, and regional impacts and threats.
Item ECOLOGIA DE PEIXES DE RIACHOS DE CAVERNAS E OUTROS HABITAT SUBTERRÂNEOS(2021) Bichuette, Maria ElinaBrasil desponta como um país rico em cavidades naturais subterrâneas, com mais de 20.000 cavernas cadastradas oficialmente. Além das cavernas, as quais se desenvolvem em diferentes tipos de rocha, há outros habitat subterrâneos (hipógeos) com corpos d’água na forma de drenagens (riachos de nível de base), de afloramentos do freático (zona saturada) em cavernas inundadas ou na forma de poças e lagos dentro de cavidades, além de bolsões de aquíferos superiores formados por água de infiltração na rocha. Em alguns casos, as águas subterrâneas não afloram em cavidades, e sim em aluviões próximos a rios, representando uma zona hiporreica. A ictiofauna subterrânea brasileira é composta por peixes restritos às cavernas e outros habitat subterrâneos (geralmente categorizados como troglóbios/estigóbios) ou por espécies que possuem populações bem estabelecidas nestes habitat, mas que também ocorrem em riachos e corpos d’água da superfície (categorizados como troglófilos). Atualmente há mais de 80 espécies de peixes com populações troglóbias e troglófilas no Brasil. Alguns estudos populacionais para peixes troglóbios/freatóbios apresentam estimativas de tamanhos e densidades populacionais variáveis, geralmente caracterizadas por populações pequenas; uma tendência ao sedentarismo; baixos valores de fator de condição e estratégias de ciclos de vida tendendo ao K dentro do continuum r-K. Estas características são relacionadas às condições abióticas únicas destes habitat, tais como aporte de nutrientes baixo, infrequente e muitas vezes imprevisível, o que pode representar um filtro acentuado. Em relação à conservação, os peixes de riachos de cavernas e de outros habitat subterrâneos encontram-se ameaçados e a maioria das espécies descritas formalmente está inserida em listas de fauna ameaçada no Brasil, apenas quatro espécies foram incluídas e avaliadas globalmente (a piaba Stygichthys typhlops e os bagres Pimelodella kronei, Phreatobius cisternarum e Phreatobius sanguijuela).- Monitoring Brazilian Cavefish: Ecology and Conservation of Four Threatened Catfish of Genus Ituglanis (Siluriformes: Trichomycteridae) from Central Brazil(2021-02-20) Bichuette, Maria Elina; Trajano, EleonoraWe investigated population parameters using the capture-mark-recapture method (Ituglanis passensis and I. bambui) and visual censuses (I. epikasrticus and I. ramiroi). The four species are regionally threatened (Brazilian Red List) and occur in caves of Terra Ronca State Park, São Domingos region, Central Brazil. We conducted seven fieldtrips across three years of dry seasons. For the capture-mark-recapture method, a 400 m long stream inside Passa Três cave, where I. passensis occurs and a 300 m long reach of an upper tributary where I. bambui occurs inside Angélica cave were divided into 20 and 17 study sections, respectively. Catfishes were hand-netted, measured (standard length), weighed, marked by subcutaneous injection of biocompatible pigments, and released. The four species show medium-to-low mean population densities (0.03 ind/m2 0.7 ind/m2). Capture-mark-recapture data pointed to a relatively small population size for I. passensis, restricted to a 1600 m long stream inside Passa Três cave (N = 719) and for I. bambui (N = 246; 300 m of epikarstic drainage). Ituglanis passensis and I. bambui move along relatively small areas with a restricted home range. We observed recruitment patterns and a trend of decrease in condition factor during the dry seasons for I. bambui but not for I. passensis, suggesting that epikarstic waters are probably more limiting concerning food input. Ituglanis passensis and I. bambui showed low growth and consequently high longevity, corroborated by captivity data (20 years). We suggest urgent actions and long-term monitoring projects to effectively protect this unique and endemic ichthyofauna.