We characterized dung beetles food preference and diel activity and examined the way such characteristics may structure a Scarabaeinae community in a dry forest. We sampled a fragment of Arboreal Caatinga in Milagres, Bahia, Brazil, during the dry and wet seasons, using baited pitfall (bovine spleen, human feces, cow dung, and rotten banana). Species were classified by activity (nocturnal and diurnal) and food preference (coprophagous, necrophagous, saprophagous, copro-necrophagous, and generalist). In total, 1,581 individuals belonging to 16 morphospecies were sampled, with six new records for Caatinga. The dung beetles were mainly from generalist and coprophagous species; seven species presented nocturnal activity, and five were diurnal. There was higher species richness during the day and greater abundance during the night. Species composition differences were influenced by functional guilds and beetle size according to temporal segregation. These factors may be related to physiological, morphological, and behavioral differences.
Dichotomius schif leri Vaz-de-Mello et al is often cited as endemic to the preserved coastal sandy-dune vegetation (restinga) of Guriri Island, Espírito Santo state, and is included in the Brazilian List of Endangered Fauna as "critically endangered" (CR). However, we recorded its occurrence in twelve additional sites along the coasts of Espírito Santo, Bahia, Sergipe and Pernambuco. The geographic distribution of D. schif leri is limited to the coastal Atlantic Forest domain, mainly in preserved restinga patches. We recommend that D. schif leri remains in the List of Endangered species, but in the "endangered" (EN) category, according to the IUCN criteria.
A biodiversidade aquática e a elevada produtividade pesqueira da Bacia Amazônica se devem principalmente à dinâmica anual dos pulsos de inundação e às extensas áreas alagáveis. Alguns dos principais impactos da construção de barragens para geração de hidroeletricidade incidem precisamente nesta dinâmica hidrológica. A construção da Usina Hidrelétrica (UHE) Belo Monte interfere na dinâmica hidrológica da Volta Grande do Xingu (VGX) ao desviar a maior parte da vazão para fora desse trecho do rio. Com base em uma análise crítica da literatura sobre o impacto de barragens e de monitoramentos em campo, que vêm sendo conduzidos tanto pelo empreendedor quanto por pesquisas independentes, verificamos que seriam necessários volumes de água substancialmente maiores do que o hidrograma proposto pela empresa e pela Agência Nacional de Águas (ANA), para não causar a total ruptura na conexão do rio com as planícies alagáveis, com efeitos negativos em cascata que comprometem, inclusive, a segurança alimentar em toda a VGX. A proposta de testar o hidrograma estabelecido pela empresa por seis anos, com uma drástica redução de vazão e perda da previsibilidade e regularidade do pulso anual de inundação, fere o Princípio Precaucionário, contraria o conhecimento ecológico acumulado sobre o tema e coloca em risco o ambiente, a biota e os modos de vida das populações humanas estabelecidas naquela região.Palavras-chave: Volta Grande do Xingu. Juruna (Yudjá). Hidrograma de Consenso. Regras de operação. Belo Monte.
This study aims to analyze how the vegetation structure (physiognomy) and seasonal changes between seasons (wet and dry) influence richness, diversity and composition of ant species of arboreal and shrubby Caatinga environments. The vegetation structure was significantly different among the three strata for all parameters (mean diameter of vegetation, level of herbaceous cover, degree of coverage and thickness of litter and percentage of canopy cover). We collected 127 ant species. The mean number of species was approximately two times higher in the rainy season than in the dry season. There was no difference in species richness between the arboreal and shrubby Caatinga physiognomies nor interaction between season and physiognomy. Despite the similarity in richness, species composition differed between physiognomies, however we found no difference in composition between seasons. The seasonal differentiation may be mainly related to the variation in the overall numbers of individuals circulating in the environment, since the enhancement of resource availability during rainy season allows the colony to grow or expand foraging activities, which increases local diversity. Water restriction explains the limited diversity in both environments, while the occurrence of species with greater resource specificity may determine differences in ant composition. Differences in composition of each of Caatinga's physiognomy enhance beta diversity, therefore, raising the overall diversity in the Caatinga Domain.
Dung beetle (Coleoptera: Scarabaeoidea: Scarabaeinae) activity is influenced by rainfall seasonality. We hypothesized that rainfall might also play a major role in regulating the community structure of this group. In this study, we describe seasonal changes in the richness, composition, and structure of the Scarabaeinae community in a Brazilian tropical dry forest. A fragment of arboreal Caatinga was sampled using baited pitfall traps during the early dry season (EDS), late dry season (LDS), early wet season (EWS), and middle wet season (MWS). We compared the dung beetle community in each season in relationship to species richness, rank-dominance, curves, and composition. We collected 1352 Scarabaeinae individuals , belonging to 15 species. Dichotomius aff. laevicollis Felsche (Coleoptera: Scarabaeidae) was the dominant species, representing 73.89% of the individuals. There were no seasonal changes in the rank dominance curves; all had a single dominant species and a few species with low abundance, typical for arid areas. Estimated richness was highest in MWS, followed by EWS. Dry-season samples (EDS and LDS) had lower richness, with no significant difference between the dry seasons. Although species richness increased as the habitat became wetter, the difference between the wet and dry seasons was small, which differs completely from the findings of other studies in Neotropical dry forests, where almost all species cease activities in the dry season. Species composition changes were found in non-metric multidimensional scaling and sustained by analysis of similarity. All the seasons had pairwise differences in composition, with the exception of EDS and MWS, which indicates that the dung beetle community in this fragment requires more than three months of drought to trigger changes in species composition; this is probably due to small changes in the forest canopy. There was no difference in composition between EDS and MWS. As in other tropical dry forests, although to a lesser extent, the dung beetle community of this fragment responded to rainfall seasonality with changes in species composition and reduced species richness. Such responses, even to this lesser extent, may occur because of small changes in tree cover and minor microclimate changes.
Response of the Histeridae (Coleoptera) Community to Different Restinga Physiognomies in Espírito SantoState, BrazilABSTRACT -Aiming to determine if the vegetation structure affects the local and regional richness and community structure of predator beetles (Histeridae), four habitats established on sandy soils (restingas and pasture) in Espírito Santo State, Brazil, with a structural complexity gradient and showing varying degrees of disturbance were surveyed with pitfall-baited traps (human and horse dung). Eight histerid species were registered. The species richness was almost equal in all habitats (4 to 5 species), and there was no significant difference in diversity and equitability. Although not significantly different in diversity, the communities could be considered different due to the gradual substitution of the dominant species and composition. The species substitution pattern was related to the change in vegetation physiognomy, which seems to impose barriers to the odour dispersion, affecting resource location, and allowing rare (but more efficient in resource localization) species to be maintained in the community. The local richness of histerids in pasture and in different physiognomies of restinga is similar and low due to the ephemeral nature of decaying resources, which impose a limit to the number of species that get to the resource. Its spatial and temporal unpredictability, by its turn, allows both common and rare species to remain in the community, the first through numeric advantage and the last through an eventual superiority in finding the resource.KEY WORDS: Community structure, dominance shift, ephemeral resource RESUMO -Buscando determinar se a estrutura da vegetação afeta a riqueza e estrutura da comunidade de besouros predadores (Histeridae), quatro ambientes no Espírito Santo, com grau decrescente de complexidade estrutural de vegetação (restinga arbórea preservada, restinga aberta de Clusia spp., restinga queimada e pastagem) foram amostrados com armadilha iscada (fezes humanas e de cavalo). Foram encontradas oito espécies de Histeridae, sendo que a riqueza de espécies foi praticamente igual nos oito ambientes (4 a 5 espécies), e a diferença de diversidade não foi significativa. Apesar da não significância, as comunidades podem ser diferenciadas pela substituição de espécies dominantes e diferenciação de composição. O padrão de substituição de espécies foi relacionado à diferença de fisionomia da vegetação, que ao impor barreiras à dispersão de odores, afeta a localização dos recursos, o que permite que espécies raras (porém mais eficientes na localização de recursos) sejam mantidas na comunidade. A riqueza local nos vários ambientes estudados não foi diferente devido à natureza efêmera (restritos quanto ao tempo em que fica disponível para colonização e terem seu poder de atração reduzido no tempo) dos recursos em decomposição, impondo uma restrição ao número de espécies. Sua distribuição aleatória e imprevisível, por sua vez, é responsável pelo caráter lotérico de sua colonização...
PhysiograPhic characterization of the olhos D'Água water basin in feira De santana/ba: gis aPPlieD to environmental analysis caracterización fisiografica De la cuenca olhos D'Água en feira De santana/ba: geoProcessamiento aPlicaDo al anÁlisis Del meDio ambiente
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