Navegando por Assunto "Natureza - influência do homem"
Item Acesso aberto (Open Access) Efeito da exploração madeireira na estrutura ecomorfológica das assembleias de peixes em riachos de terra firme na Amazônia Oriental(Universidade Federal do Pará, 2018-04) JACOB, Laís Lobato; PRUDENTE, Bruno da Silveira; http://lattes.cnpq.br/0790796091423878; https://orcid.org/0000-0003-4226-2431; SILVA, Rogério Rosa da; http://lattes.cnpq.br/5989181105383977Changes resulting from logging modify the physical structure of stream habitats indirectly, and consequently the ecomorphological structure of fish assemblages. The present study aimed to evaluate the effect of changes in the physical structure of the habitat resulting from conventional logging (CL) and reduced-impact logging (RIL), in the ecomorphological structure of the fish assemblages of streams of the Eastern Amazon, verifying (1) which variables of the physical structure of the habitat are associated to the different methods of exploration; (2) if there is a difference in the ecomorphological structure of the fish assemblages of the different treatments, and (3) which ecomorphological characters are associated with physical variables of the habitat. In each stream 14 physical variables of the habitat were measured, as well as fish samples collected using hand nets. The collected specimens were affected in Eugenol, fixed in 10% formalin and after 48h transferred to 70% alcohol. Possible differences in habitat structure and ecomorphological structure of fish assemblages between treatments were evaluated by Multiple Linear Discriminant Analysis (MLDA). The relationships between the habitat variables and the ecomorphological characters were evaluated through Redundancy Analysis (RDA). The structure of the streams habitat differed among all treatments, with control areas showing higher vegetation cover and higher average substrate size. As for ecomorphology, we also found that there was a difference in ecomorphological structure among all treatments. In EC environments, species with greater relative head length, with the wider pectoral fin and with more compressed caudal peduncle were predominant in these environments; in control areas, species with wider mouth were favored; and in RIL areas, more flattened species were predominant. Logging affects the habitat structure of the streams, resulting in loss of plant cover and average substrate size. There was a reduction of plant cover and average substrate size in areas of EC and RIL areas. In this sense, it is believed that both the EC and the RIL have the potential to alter the ecomorphological structure, and consequently the ecosystem services provided by the assemblages of fish from streams in the Amazon. So even if EIR reduces damage to forests, it is failing to protect the ecosystems of streams, since changes have been observed in these environments when compared to control areas. However greater efforts should be employed to fully understand such a relationship and proportions that the damage can cause to the ecosystem.Item Acesso aberto (Open Access) O efeito das espécies raras e comuns na diversidade funcional de aves florestais em uma paisagem dominada por palma-de-dendê na Amazônia Oriental(Universidade Federal do Pará, 2024-03) PINHEIRO, Beatriz Tavares; ALMEIDA, Sara Miranda; http://lattes.cnpq.br/2785084573828283; HTTPS://ORCID.ORG/0000-0002-8372-5482; SANTOS, Marcos Pérsio Dantas; http://lattes.cnpq.br/7941154223198901; https://orcid.org/0000-0001-8819-867XThe advance of agro-industry in the Amazon is a major threat to biodiversity, causing intense deforestation to make way for cattle ranching and monocultures such as palm oil. Forest loss can alter the distribution and population size of rare species that are limited in number of individuals or area of occurrence, affecting the functional structure of communities and ecosystem services. In this study, we assessed the contribution of rare and common species to the functional diversity of forest bird communities in a landscape dominated by oil palm plantations. Bird sampling was conducted using a point count method in oil palm plantations and forest fragments in the eastern Amazon, Brazil. A total of 232 bird species was recorded, of which 198 occurred in the fragments and 53 in plantations. For each species occurring in forest fragments, we calculated a rarity index combining local abundance, geographic range and habitat specificity. We calculated functional richness (FRic), functional originality (FOri), functional specialization (FSpe) and community-weighted trait means (CWM), and compared them between forest and plantation communities considering three scenarios: 1) total pool of species recorded in forest versus plantation; 2) rarest species are removed from forest; and 3) more common species are removed from forest.There was a clear difference in trait composition between the two habitats. Removal of rare species increased functional diversity, but decreased functional redundancy. In contrast, the removal of common species reduced FOri and FSpe values, demonstrating that common forest bird species make unique functional contributions. We conclude that the loss of both rare and common species affects forest bird communities, and that it is essential to conserve and protect forested areas to ensure ecosystem health and resilience.Item 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/0000-0001-9717-5461The 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.Item Acesso aberto (Open Access) Efeitos de perturbações antrópicas sobre os fatores ambientais e espaciais na estruturação de metacomunidades de insetos aquáticos na Amazônia Oriental(Universidade Federal do Pará, 2022-07) OLIVEIRA, Stéfany Vitória Santos; 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/0000-0001-9717-5461Anthropogenic pressures resulting from changes in land use have great potential to impact the dynamics of aquatic insect metacommunities, once they alter the environmental quality of streams, and may impose barriers to dispersal. The objective of this study is to evaluate the structuring of aquatic insect assemblages (Ephemeroptera, Plecoptera and Trichoptera orders - EPT) in Amazonian streams under natural conditions (control streams) and under disturbance by human activities (altered streams) is influenced by characteristics of fluvial habitats and by the spatial structure. Our hypotheses is that in control streams, habitat characteristics are the main structuring factor of EPT assemblages, and that in altered streams, habitat characteristics related to human disturbances and spatial structure are the main assemblage structuring factors. A total of 74 streams were sampled in the Capim River basin, Pará, Brazil, wich 38 are control streams and 36 are altered streams. In each of them, environmental variables associated with water chemistry, channel hydromorphology, sediment types, riparian vegetation and insect shelter were measured, in addition to the proportion of land uses and EPT assemblages. Our results showed that several environmental characteristics of the streams were affected by human activities. Environmental factors had a greater influence on the structuring of EPT assemblages than the other factors evaluated, both in the control and altered streams. The influence of the spatial factor was weak. The assemblages of altered streams were structured both by environmental variables affected by disturbances and by variables subject to natural variation, demonstrating that the assemblages in these environments are not governed only by environmental changes. Our study demonstrates the importance of the species sorting process in metacommunities of Amazonian streams, and the role of disturbance in this process.Item 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/6664624762387564Deforestation, 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.Item Acesso aberto (Open Access) Trilha de pesquisador e trilha de morador: análise comparativa para o monitoramento da fauna em duas unidades de conservação na Terra do Meio, Amazônia Oriental, Brasil(Universidade Federal do Pará, 2021-04-30) SANTOS, Paola Maria Feio; ENDO, Whaldener; http://lattes.cnpq.br/8408566223923754; https://orcid.org/0000-0002-7305-4398; PEZZUTI, Juarez Carlos Brito; http://lattes.cnpq.br/3852277891994862; https://orcid.org/0000-0002-5409-8336The Amazon has a high diversity of medium and large vertebrates, which are essential for forest dynamics. They stand out for being the most hunted by local human populations and, as a result, it is likely that changes in the composition, wealth and abundance of this group of animals will occur throughout the territory. This human-animal interaction creates disturbances for both parties, reducing the chances of direct or indirect encounters, causing losses to the subsistence hunting of local communities. Due to this situation, the ability of wildlife to persist in areas of varying human densities is discussed, especially in protected areas, and it is necessary to establish monitoring programs to understand and deal with the threats mentioned above. This work sought to evaluate the feasibility of using trails of residents (TM) for monitoring vertebrates, comparing the results obtained in trails of researcher of the protocol TEAM (TPt) and trails of researcher of the Minimum Protocol (TPm). An Non-Metric Multidimensional Scaling (NMDS) analysis, rarefaction curves and richness demonstrated that there was a significant difference in the composition of species obtained in TM, TPt and TPm. Despite the significant difference between the areas, the richness and abundance data in TPt were more stable among all registered species, in addition to showing a similarity with the richness and abundance data obtained in TM. Therefore, it is possible that future monitoring actions may take place in the trails of residents present in extractive reserves.