Life-history and disease ecology of the brown-nosed coati (Nasua nasua) and the crab-eating fox (Cerdocyon thous) in the Brazilian Pantanal

Title from PDF of title page (University of Missouri--Columbia, viewed on August 23, 2010).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. Matthew Gompper.Vita.Ph. D. University of Missouri--Columbia 2010.Infectious diseases can be significant threats to public health and wildlife. Yet, there is still a relatively poor understanding of the impact parasites have on the health and demography of wild hosts. Understanding the effects of parasites on hosts requires not only knowledge about the parasites themselves, but also about the ecology of their hosts. This dissertation was developed with this aim in mind. The first and second chapters regard, respectively, the development of a tool for aging coatis (Nasua nasua: Linnaeus, 1766) and the crab-eating fox (Cerdocyon thous; Linnaeus, 1766) and the collection of basic information on the life-history of these species in the Brazilian Pantanal. In the third chapter, I focus on ectoparasites of coatis and foxes, particularly on ticks. I investigate how abiotic factors and the host attributes influence tick abundance and prevalence on hosts. This chapter can be considered a model for investigating the relative importance of biotic and abiotic factors in parasite dynamics. Finally, in chapter 4 I focus on how hemoparasites and gastro-intestinal parasites affect coati health. There are few studies which have investigated the effects of multiple parasites on direct measures of the health parameters of free-ranging hosts. In this sense, this last chapter can also be viewed as a model for future studies focusing in the interplay between parasites and health of wild, free-ranging mammals.Includes bibliographical references

Modulating Variables ofTrypanosoma cruziandTrypanosoma evansiTransmission in Free-Ranging Coati (Nasua nasua) from the Brazilian Pantanal Region

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Immediate impact of fires on roadkilling of wild vertebrates on a highway in southeast Brazil

Fires cause wild vertebrates to try to escape, thereby leading to an increase in attempts to cross roads and consequently an increase in the number of roadkills. However, the study of the impact of fires on roadkilling of wild vertebrates is practically nonexistent. In this study, we analyzed the relationship between fires near a 180 km highway stretch in Southeast Brazil and wild vertebrate roadkills using a 7-year dataset on roadkills and satellite data on fires, hypothesizing that roadkills would increase after fires. We found that the number of roadkilled wild vertebrates increased by about 144% (P = 0.020) in highway sections up to 1 km from fires, within 7–8 days after the fires. The number of roadkills in highway sections affected by fires was also higher than that of neighboring (control) section (P = 0.028). Taken together, these results show there was a significant increase in the number of roadkills on road sections close to or within burned areas. This work emphasizes the importance of analyzing the synergistic effects of fires and roadkill of wild vertebrates and guides research on adopting an experimental design which allows for temporal and spatial controls using retrospective data on fires and roadkilling. We recommend decreasing traffic flow and/or vehicle speed near areas recently affected by fires, as a preventive management strategy

Comparing the effectiveness of tracking methods for medium to large-sized mammals of Pantanal

Most Neotropical mammals are not easily observed in their habitats, and few studies have been conducted to compare the performance of methods designed to register their tracks. We compared the effectiveness of track registry between sand plots and two tracking methods that use artificial materials to record tracks: the sooted paper, and the plastic board methods. The latter is described here for the first time. From 2002 to 2005, we conducted two experiments in three study sites in the Pantanal region of Brazil. We compared the artificial methods with the sand plot by registering track presence/absence, the number of identifiable tracks, and the total number of tracks (identifiable and unrecognizable) in each tracking plot. Individuals avoided artificial tracking plots either by not stepping on them or by doing it fewer times than on the sand plots. The use of artificial materials to register mammal tracks resulted in underestimates that are especially relevant to short-term ecological studies. We recommend the use of the traditional sand plot method whenever possible and the development of detailed studies on the efficiency of artificial methods under a variety of environmental conditions and time lengths. Despite their relatively lower efficiency, we believe that artificial methods are useful under specific conditions and may be more efficient if used in more comprehensive sampling efforts