Long-term effects of reduced impact logging on primate assemblages in eastern Amazonia, Brazil.
Master thesis
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https://hdl.handle.net/11250/3148339Utgivelsesdato
2024Metadata
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- Master’s theses (MINA) [759]
Sammendrag
In the Amazonian rainforest, logging poses a significant threat to the ecosystem integrity. This study researches the impacts of reduced impact logging on primate species in a secluded forest area in the Northeastern Amazon biome. The objectives are to assess the trend for primate populations and primate assemblage composition and comparing these parameters over a decided time period covering 20 years (2002-2023) and dividing the data into three time periods to get a good estimate of differences over the years (Period 1, 2 and 3). However, the long-term effects of RIL are poorly studied, especially for primates. Many studies that have researched the short-term effects of RIL on vertebrates show that the populations for most the part are more or less unaffected. The data for the years 2002-2013 are from the database by Universidade Federal do Para and was gathered by walking line transects in various lengths, depending on the year. Our own data was collected by walking transect lines of 5km from October to November in 2023. In total six primate species were recorded, and the species with the most decline in observations from Period 1 to Period 3 were Red-handed howler monkey, Black tamarin, and Tufted capuchin, also being the most common species in the area. Black saki observations remained consistent over the time periods, while Collins Squirrel monkey and Kaapori capuchin observations increased over time. The mean group size increased for the Red-handed howler monkey, Black saki, Black tamarin, Collins squirrel monkey, and the Tufted capuchin, and decreased for the Kaapori capuchin. This indicates that the group sizes for most species are increasing, even though the observations of individuals are decreasing, resulting in fewer but larger groups. The encounter rate (individuals per km) declined for the Red-handed howler monkey, Black tamarin, and Tufted Capuchin, and increased for Kaapori capuchin, Black saki, and Collins squirrel monkey. Statistical calculations showed that there were significant differences among the time periods for three of the species, Red-handed howler monkey, Kaapori capuchin and Black tamarin. The results suggest that even if the mean group size and encounter rate has declined for some of the species RIL does not seem to have a heavy negative impact on primate assemblage in the area.
Keywords: primates, reduced impact logging, amazon