Navegando por Assunto "Impacto antrópico"

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Acesso aberto (Open Access)
Aplicação de dados multisensor (SAR e ETM+) no reconhecimento de padrões de uso e ocupação do solo em costas tropicais: Costa Amazônica, Amapá, Brasil
(2009) SANTOS, Valdenira Ferreira dos; POLIDORI, Laurent; SILVEIRA, Odete Fátima Machado da; FIGUEIREDO JÚNIOR, Alberto Garcia de
Environmental studies require information on land use and land cover. This paper presents the applicability of multi-sensor satellite data (optical and radar) for land use and land cover on the Amapá coastal plain for mapping and recognition of natural and anthropogenic dynamics. This area is influenced by the Amazon River, by tides (tidal bore) and by the Intertropical Convergence Zone (ITCZ). Anthropogenic processes are associated with water buffalo ranching. The environmental information was acquired from previous data and field observation and was correlated with remote sensing data (JERS-1, RADARSAT-1, image from ETM+ sensor from Landsat 7 and DEM SRTM), digitally processed for multi-sensor, multi-scale and multi-date approach. Eight patterns of land use and land cover were identified (mangrove, "várzea" forest, arbustive vegetation area, freshwater marsh, anthropic field, intertidal plain, estuarine channel and lakes) as well with indication of natural and anthropogenic geomorphic features. The results from the evaluation of remote sensing data and the techniques applied demonstrated the potential of the remote sensing tool for studying environments in highly dynamic tropical coastal areas of difficult access. However, these tools may present some limitations once applied to application to the Amazon coast, which is a region under strong dynamic natural and anthropogenic processes.
Acesso aberto (Open Access)
Diversidade de insetos aquáticos em riachos urbanos: a importância de fragmentos florestais
(Universidade Federal do Pará, 2024-12-13) JORDAN BOUCHON, Yildiz Thais; BEASLEY, Colin Robert; http://lattes.cnpq.br/6310836748316181; HTTPS://ORCID.ORG/0000-0003-1413-1469; QUINTEIRO, Fábio Batagini; http://lattes.cnpq.br/1531054078905516
Urban expansion is a reality in the Amazon biome, which has transformed aquatic ecosystems, with a decrease in water quality and a reduction in the diversity of organisms. Groups of species, such as aquatic insects, can indicate the biotic condition of the ecosystem through the frequency and occurrence of taxa indicators. The environmental disturbances caused by urbanization can be detrimental to the survival of some sensitive aquatic insects in Amazon rivers. The aim of our study was to evaluate the environmental condition and diversity of aquatic insects in streams in secondary forest and urban streams in the municipality of Bragança, Pará, Brazil. Data on insect groups, environmental variables and levels of disturbance (using the Habitat Integrity Index, HII) were collected between October and December 2023. A total of 423 individuals were collected, 69 in the streams of the secondary forest and 354 in the urban streams, distributed in the orders Ephemeroptera, Trichoptera, Odonata, Diptera, Coleoptera and Hemiptera. Twenty-two families were recorded in urban streams and 12 families in the secondary forest. The patterns of abundance and richness showed a decrease as the months progressed in both environments. The BergerParker dominance index in both environments showed an increase as the months went by, indicating a change between the insect communities. On the other hand, the Margalef diversity index in both environments decreased over the months. According to the levels of environmental disturbance assessed, both environments were classified as “altered” (IIH<0.70) A positive association was demonstrated between the abundance of Hydropsychidae and the variables of electrical conductivity and total dissolved solids. Environmental variables such as electrical conductivity, total dissolved solids, phosphate and dissolved oxygen are associated with variation in the composition of aquatic insect groups. Strong relationships were recorded between the distribution of Gomphidae and phosphate concentrations. Corduliidae was related to total dissolved solids and electrical conductivity. Coenagrionidae and Caenidae showed positive responses to dissolved oxygen. The study showed a greater number of aquatic insect families in the area with strong anthropogenic pressure than in the secondary forest area, possibly due to a high diversity of microhabitats. In addition, urbanization factors could be negatively affecting both environments.
Acesso aberto (Open Access)
Mangrove vegetation in Amazonia: a review of studies from the coast of Pará and Maranhão States, north Brazil
(Instituto Nacional de Pesquisas da Amazônia, 2008) MENEZES, Moirah Paula Machado de; BERGER, Uta; MEHLIG, Ulf
The present study is a compilation of the literature about vegetation of mangrove forest of the north coast of Brazil. It synthesizes the knowledge about this important ecosystem and lists the currently available literature. The study focuses on the coast of Pará and Maranhão states, which are covered by a continuous belt of mangroves. The mangrove flora comprises six mangrove tree species and several associated species. Mangrove tree height and stem diameter vary as a function of abiotic local stand parameters. Seasonal variation in rainfall and salinity affect the species' phenology and litter fall. Local population use products derived from mangrove plants for different purposes (e.g. fuel; medicinal; rural construction). The increase in the coastal population has given rise to conflicts, which impact on mangrove forest.
Acesso aberto (Open Access)
Relationship of Neotropical otter vestiges with environmental and anthropogenic factors
(Instituto Nacional de Pesquisas da Amazônia, 2019-09) COSTA, Ana Marta Andrade; ARCOVERDE, Danilo Leal; ALBERNAZ, Ana Luisa Kerti Mangabeira
The Neotropical otter, Lontra longicaudis (Mustelidae) is a semi-aquatic mustelid that exploits a variety of freshwater habitats. To understand the relative influence of human activities and environmental factors affecting its distribution and habitat use, we conducted systematic, seasonal surveys of otter signs along the middle Guamá River, in Pará state in the eastern Brazilian Amazon. We applied generalized additive models to compare distribution of otters along the river with data collected on environmental factors (landcover type derived from satellite imagery, and in situ measurements of physicochemical water characteristics) and anthropogenic factors (fishing gear in the river and human habitation along the river). Most otter signs (indicators of otter habitat use) occurred along the shoreline of the main river channel during the dry season; we observed fewer signs during peak flow, probably because the shoreline and floodplain are flooded, which hid signs and made access to the floodplain difficult. The best-fit model included variables for proportion of forest, presence of fishing gear and boats, bank steepness, and presence of rock formations and sand banks. Otter occurrence was negatively related to forested area and positively related to the presence of fishing gear and boats. Otters are likely attracted to fish trapped in fishing gear because they can easily predate on the trapped fish.
Acesso aberto (Open Access)
Tree responses to soil and edge effects in a semideciduous forest remnant
(Instituto de Florestas da Universidade Federal Rural do Rio de Janeiro, 2018-07) TERRA, Marcela de Castro Nunes Santos; TEODORO, Grazielle Sales; PIFANO, Daniel Salgado; FERNANDES, Fernando Bonillo; SILVA, Tainá Mamede Cirne; BERG, Eduardo van den
The present study seeks to characterize the composition, structure, and functional traits of the tree stratum of a Semideciduous Forest in Pouso Alegre, MG, Brazil (22º12’43”S and 45º59’30”W), by comparing Edge and Interior habitats and their relation to human impacts and soil variables. The tree community (diameter at 1.3 m (DBH) higher than 5 cm) was inventoried using the point-centered quarter method by laying out 12 transects of 450 m each (six transects in the Edge and six in the Interior). Functional traits – wood density and seed mass – were obtained by genus. The impact evaluation and soil sample collection were realized per transect. We found significant differences in terms of the basal area (higher in Interior), diversity (higher in Interior) and community seed mass (higher in Edge). The effects of higher values of soil traits such as Calcium, Magnesium, cation sum (CS) and base saturation (V) on species composition were stronger in the Interior, while human induced impacts and soil Potassium had an overwhelming effect on the Edge.