Estudo do efeito da antropização sobre a diversidade de animais silvestres e o parasitismo por ectoparasitas no assentamento Rio Pardo - AM

Abstract

The Amazon is the largest tropical forest in the world, home to enormous biodiversity, including several species of small mammals and their parasites. Anthropization, especially through the creation of rural settlements and agricultural expansion, has caused significant changes in local ecosystems, affecting the distribution and prevalence of ectoparasites such as ticks and mites. The objective of this study was to investigate the diversity of small wild mammals and the prevalence of ectoparasites, specifically ticks and mites, in the Rio Pardo Rural Settlement, in the municipality of Presidente Figueiredo, AM. Data collection was carried out in different types of environments (Forest, Capoeira, Plantation and Home) and in two distinct periods in different climatic seasons (dry and rainy). Ectoparasites from small mammals were collected using Sherman and Tomahawk traps. The ectoparasites were removed from the animals' skin by inspection and removed manually, stored in 70% alcohol until identification, with the aid of a stereomicroscope, taxonomic keys and literature database. For hard ticks, they were photographed with the ZEN Pro 2 software, which is attached to a Stereo Discovery V12 stereomicroscope. As for soft tick larvae (Argasidae), it was clarified and a slide was made and its morphology was compared with other literature. For analyzes of host diversity indices, rarefaction curves, relative abundance versus richness, Margalef index, equitability and the non-parametric Simpson index (1 -D) were used. To analyze animal infestation, univariate analysis was used to verify the association between a higher prevalence of infestation and potential risk factors using Person's Chi-square test or Fisher's exact test. The prevalence, mean abundance and mean intensity of ticks and their respective confidence intervals (95% CI) were calculated using the Quantitative Parasitology 3.0 software. The capture rate of animals was prevalent in the Rodentia order. Capoeira presented the greatest diversity of animals with 124 registered species and the highest Margalef index, indicating a high specific diversity. The Forest presented high levels of Simpson and J Equitability. There was a prevalence of ectoparasite infestation of 21.2%, ticks with 6.7% and mites with 14.4%. Factors such as lower anthropization, order didelphimorphia and the Cricetidae family showed a significant presence of mites. In view of the tick analyses, there was a prevalence in relation to the order didelphimorphia. The most prevalent species was Amblyomma sp., of the infested animals examined. The study brought unprecedented results on the tick fauna in Northern Brazil, as well as parasite-host relationships. The results indicate that less anthropic environments, such as Forest and Secondary vegetation, have a greater diversity of small mammals and a significant prevalence of ectoparasites. The conservation of heterogeneous habitats is crucial for maintaining biodiversity and mitigating the risks associated with ectoparasites. This study provides a solid foundation for future research and conservation strategies in the Central Amazon.