Navegando por Assunto "Impacto ambiental - avaliação"

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Acesso aberto (Open Access)
Diversidade morfológica de aves e extinções na Região Metropolitana de Belém, Pará, Brasil
(Universidade Federal do Pará, 2018-03) SILVA, Victória de Nazaré Gama Silva; ALEIXO, Alexandre Luis Padovan; SILVA, Rogério Rosa da; http://lattes.cnpq.br/5989181105383977
Morphological diversity, a concept intimately related to functional diversity, involves the characterization of the diversity of phenotypic characters and can be used as a measure of diversity in communities. The morphological approach has traditionally been applied in studies on structuring bird communities. In this study, we evaluated if bird extinctions documented in the Metropolitan Region of Belém (MRB), located in the northeast of the State of Pará, may have altered the morphological space of birds in the region. Initially, bird records for the MRB were compiled from the literature, resulting in 490 species documented. The database on regional extinctions of birds or endangered species was determined for the MRB, from literature, which resulted in four lists (subsets of the total species list in the MRB). In the final phase of data acquisition, we organized a morphological matrix for the birds of the MRB, defined by measurements of 2,360 individuals and nine characters commonly used in studies on bird ecology and morphology (beak, wing, tail, and tarsus length data). The morphological space occupied by the bird fauna in the MRB was described by a Principal Component Analysis. Morphological diversity metrics (MPD and MNND) were used to compare observed values with scenarios of extinctions in the MRB (the four lists of species that were a subset of the regional fauna). Simulated extinctions of MRB’s bird fauna were used to determine expected values in random extinction models or probability models of extinction. The results suggest that if the MRB lose species that delimit the periphery of the morphological space, changes in the morphological structure of the bird fauna can be expected, although a relatively small number of species disappear. Simulated models of extinction indicate a monotonic relationship between morphological diversity and species richness, strictly decreasing, indicating that the MRB will lose functional diversity with accumulated extinction of species; on the other hand, morphological space structure (such as MPD and MNND), suggest a greater functional redundancy of birds in the region. Taken together, the results indicate significant effects of regional extinctions on the morphological structure of MRB birds, with possible functional consequences for the region.
Acesso aberto (Open Access)
Efeitos de atividades de subsistência de ribeirinhos sobre a heterogeneidade ambiental e a diversidade de insetos aquáticos em diferentes níveis espaciais de riachos amazônicos
(Universidade Federal do Pará, 2021-09) COSENZA, Jorge Felipe Abreu; FARIA, Ana Paula Justino de; http://lattes.cnpq.br/6041546003155327; https://orcid.org/0000-0003-2729-5358; SANTOS, Raphael Ligeiro Barroso; http://lattes.cnpq.br/7227882802366966; https://orcid.org/0000-0001-9717-5461
The deleterious effects of large-scale impact activities such as agriculture, intensive ranching, dam construction and mining on Amazonian biodiversity have been constantly studied. On the other hand, the effects of smaller-scale impact activities are neglected. An example is the activities practiced by traditional populations, such as riverside populations, who have lived for generations on the banks of rivers and streams in the Amazon basin. There are still few studies that evaluate the effects of anthropic activities considered to have less impact on the diversity patterns of aquatic insects at different spatial scales using taxonomic and functional approaches concurrently. Thus, we evaluated how subsistence activities practiced by riverside populations affect the taxonomic and functional alpha and beta diversity of aquatic insects of the orders Ephemeroptera, Plecoptera and Trichoptera - (EPT), at different spatial levels (between sampling units within streams and between streams). We tested the hypotheses that (H1) the altered streams have less environmental heterogeneity among themselves and the composition of environmental characteristics different from the control streams; (H2) altered streams have lower alpha taxonomic and functional diversity than control streams; (H3) the taxonomic and functional beta diversity between sampling units and between altered streams is lower than between sampling units and control streams; (H4) the beta diversity observed between sampling units and between altered streams is generated primarily by richness difference, while between sampling units and control streams, the replacement of species/functional groups predominates. We conclude that the disturbance caused by the riverside populations subsistence activities, specially navigation, altered the characteristics of the habitats and, in certain aspects, the EPT assemblages of the streams of the Caxiuanã region. Beta diversity patterns did not change, but there was a loss and increase in abundance of some genera as a result of the changes. Thus, the maintenance of beta diversity is not necessarily a sign of high diversity and ecological integrity, as the increased variation in the composition of these assemblages may be a result of the loss of sensitive species and the increase of more generalist species. The functional approach responded similarly to the taxonomic one in all environments and spatial levels, which suggests that this effect is dependent on the biological group analyzed and on the type and intensity of change in the environment. The activities practiced by the riverside populations altered the local community of aquatic insects in a less impactful way compared to other activities commonly practiced in the Amazon, such as logging, agriculture, palm plantation, grazing and mining. To reduce a possible loss of species in the streams in the region, it is necessary to maintain the natural conditions of the habitats, such as a high density of vegetation cover on the banks, a large number of leaf banks in the riverbed and a high frequency of slow flows.
Acesso aberto (Open Access)
Fatores determinantes na ocorrência de espécies de carnívoros (Mammalia: Carnivora) em áreas degradadas na amazônia oriental
(Universidade Federal do Pará, 2018-05) RIBEIRO, Ana Carolina da Cunha; OLIVEIRA, Ana Cristina Mendes de; http://lattes.cnpq.br/1199691414821581; https://orcid.org/0000-0002-7863-9678; WIIG, Oystein; http://lattes.cnpq.br/6664624762387564
Deforestation, habitat fragmentation, and forest impoverishment have led to a reduction in biodiversity and loss of ecosystem functions in the Amazon Rainforest. Due to the context of high anthropogenic pressure, the importance of degraded primary forests and secondary forests for the conservation of tropical species has been discussed in the literature. In this work, we investigate the characteristics of a degraded landscape have been determinant for the occurrence of species of the order Carnivora, in a context of high anthropic pressure in the eastern Amazon. As the use of photographic traps, we related environmental and landscape variables with the abundance of the species using Generalized Global Models analyzes. The responses of the carnivorous species were differentiated about some variables. However, we concluded that even in a context of high degradation, the factor that still modulates the occurrence of most carnivores is the forest, even if degraded.
Acesso aberto (Open Access)
Variação temporal de Ephemeroptera, Plecoptera e Trichoptera (EPT) com base em sua especificidade ambiental em riachos impactados pela mineração na Amazônia Oriental
(Universidade Federal do Pará, 2022-03) PÉREZ, Juan Mateo Rivera; JUEN, Leandro; http://lattes.cnpq.br/1369357248133029; https://orcid.org/0000-0002-6188-4386; FEITOZA, Yulie Shimano; http://lattes.cnpq.br/7380463661182614; https://orcid.org/0000-0003-2931-4719
Knowing aquatic diversity and understanding how different species are distributed in time and space has become one of the main focuses of research in ecology in recent decades. This is mainly due to the rapid environmental changes caused by human activities. In this scenario, aquatic insects of the orders Ephemeroptera, Plecoptera, and Trichoptera (EPT) are used to monitor environmental conditions because they are sensitive to these changes. The intensity of the response depends directly on the breadth of the niche of each taxon given the variability and changes in the habitat. With the general objective of investigating the effects of iron mining based on the environmental specificity of EPT in streams of the Carajás National Forest in Pará, over six years, this dissertation is divided into two chapters. In the first, we classified EPT taxa into generalists and specialists and evaluated whether the estimated abundance and richness of these groups vary according to the level of alteration of the streams impacted by mining activities. In the second, we evaluated the spatial and temporal variation of the beta diversity of generalist and specialist EPT. In both studies, EPT data sampled annually in 24 streams over six years were used in streams conserved and impacted by mining in the Carajás Flona. A total of 49,922 individuals distributed in 59 genera were collected, of which 31 were classified as specialists and 28 as habitat generalists. In the first chapter, we verified that there was a negative effect of mining on the estimated wealth and a positive effect on the abundance of specialist genera. On the other hand, the abundance and estimated wealth of generalists were negatively influenced by the mining effect. In the second chapter, no differences were found in gender composition or heterogeneity between treatments. However, over time, both generalists and specialists changed their composition. Mining affects the communities of EPT generalists and specialists, in particular, specialists from sites impacted by mining that showed an increase in their abundances, possibly due to the expansion of habitat made available by the process of habitat homogenization. For generalists, gender loss was the main component in temporal beta diversity, while specialists showed gender gains and losses. Therefore, mining has affected communities of both generalist and specialist groups over the years, despite their habitat specificity, presenting different patterns of environmental changes.