Influence of the landscape structure on the movement patterns of the crab-eating fox (Cerdocyon thous)

Author(s)

Claudia Zukeran Kanda

• Document type: Doctoral Thesis
• Press: Rio Claro. 2021-10-29.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Biociências. Rio Claro
• Defense date: 2021-09-27
• Advisor: Milton Cezar Ribeiro

Abstract

Understanding the mechanisms that drive the movement of animals in different landscape conditions can help to predict how the effects of changes in the landscape can change the dynamics of space use and, consequently, the interaction between organisms. In this context, the crab-eating fox has interesting ecological characteristics to we start to explore more about its movement ecology, as it has a wide geographic distribution and occurs from natural to anthropized environments. Thus, in this thesis, I approach different analyzes of movement patterns and space use of this generalist social carnivore in two forest landscape contexts, one with approximately 15% and the other with approximately 50% forest cover. To investigate the proposed theme, my specific objectives were developed in distinct chapters, which I describe below. In chapter 01, I did literature review about the ecology and movement ecology of this species. I also included information obtained during the development of this thesis. Most of the information about the spatial ecology of the species in Brazil was obtained through radio monitoring and is present in gray literature (dissertations and theses) in Portuguese. Added to these lack of scientific publications, almost all studies were limited to assessing the size of the home range and overlap, as well as the use and selection of habitat. No study explored details of the mechanisms that could be shaping the observed movement patterns. Despite the crabeating fox being considered a generalist canid, my results highlight the divergence between the high records of the species distribution and limited ecological knowledge about it. These knowledge gaps regarding its ecology could be difficult to assess the impact of threats on the population and the effects of its movement ecology on the ecological process. In chapter 02, I assess whether movement patterns differ between landscapes. For this purpose, I classify the movement strategies (e.g., resident, nomadic, migratory or dispersal) and movement modes (e.g., exploratory or stationary) of the wild dog into two temporal scales, oneyear time series and two-year time series. My results indicate that the crab-eating fox has a residency strategy with occasional exploratory modes and also, some dispersal individuals, regardless of the landscape context studied. In chapter 03, I estimate the size and the time to cross its home range, as well as if the daily distance moved and the activity pattern differs between the two forest landscapes studied. Our results provide indications of the relationship between the landscape context and the spatial organization of the population, indicated by an increase in home range and a decrease in the spatial overlap between individuals in the continuous forest landscape. 5 Finally, in Chapter 04, I assess the presence and the interval of periodic movements within the home range in two forest landscape contexts. Periodic movement patterns were more present and with the high significance of daily periodicity in the forest patches landscape than in the forest landscape. These results, possibly indicating high border patrol of territory and the use of resource patches within their home ranges in the patchy landscape. At the end of the thesis, I present the general conclusions and the research activities developed during my doctoral period. In summary, this thesis highlights the importance of considering the influence of the environmental context on the movement and spatial organization of a population. And also, these variations could imply different effects in the environment when we integrate the relationship between animal movement and its ecological function, shaping the time and place in which this function may occur. (AU)

• FAPESP's process: 16/11595-3 - Influence of landscape structure in movement patterns and population density of the Crab-Eating Fox (Cerdocyon thous)
• Grantee: Claudia Zukeran Kanda
• Support Opportunities: Scholarships in Brazil - Doctorate