Influência da estrutura da paisagem nos padrões de movimento do cachorro-do-mato (Cerdocyon thous)
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Data
2021-09-27
Autores
Kanda, Claudia Zukeran [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Compreender os mecanismos que impulsionam o movimento dos animais em diferentes condições de paisagem pode contribuir para prever como os efeitos das mudanças na paisagem podem alterar a dinâmica do uso do espaço e consequentemente, a interação entre os organismos. Neste sentido, o cachorro-do-mato apresenta características ecológicas interessantes para começarmos a entender um pouco mais sobre a sua ecologia de movimento, por possuírem uma ampla distribuição geográfica e ocorrer desde ambientes naturais a antropizados. Desta forma, eu abordo nesta tese, diferentes análises de padrões de movimento e uso do espaço deste carnívoro social generalista em dois contextos florestais de paisagem, uma com aproximadamente 15% e outra com cerca de 50% de cobertura florestal. Para investigar o tema proposto, meus objetivos específicos foram desenvolvidos ao longo dos capítulos de minha tese, as quais descrevo abaixo. No capítulo 01 faço uma revisão bibliográfica a respeito da ecologia geral e ecologia do movimento da espécie e informações obtidas durante o desenvolvimento desta tese. A maior parte das informações disponíveis sobre a ecologia espacial da espécie no Brasil foram estudos de monitoramento realizados via rádio-telemetria, sendo estas disponíveis em literatura cinza (dissertações e teses) na língua portuguesa. Somado a esta carência de publicações científicas, quase todos os estudos se limitaram a estimar o tamanho da área de vida e sobreposição entre elas, assim como o uso e seleção de habitat. Nenhum estudo se aprofundou em analisar os mecanismos que poderiam estar moldando os padrões de movimento observados. Apesar de ser um canídeo generalista, os resultados reforçam a divergência entre os registros de ocorrência da espécie e os conhecimentos reais a acerca da espécie. Estas lacunas de conhecimento a respeito da ecologia da espécie podem dificultar a avaliação do impacto das ameaças na população e do entendimento dos efeitos de sua ecologia de movimento nos processos ecológicos. No capítulo 02, eu avalio se os padrões de movimento do cachorro-do-mato diferem entre as paisagens. Para isso, eu classifico as estratégias de movimento (e.g. residente, nômade, migratório ou dispersivo) e modos de movimento (e.g., exploratório ou estacionário) do cachorro-do-mato em duas escalas temporais, série temporal de um ano e série temporal de dois anos. Os resultados indicaram que o cachorro-do-mato possui estratégia sedentária com alguns modos exploratórios eventuais e também, alguns indivíduos dispersivos, independente do contexto da paisagem estudado. No capítulo 03, eu avalio se o tamanho e o tempo de cruzar a sua área de vida, assim como a distância diária percorrida e o padrão de atividade diferem entre as duas paisagens florestais estudadas. Nossos resultados fornecem indicações da inter-relação entre o contexto da paisagem e a organização espacial da população, indicando um aumento na área de vida e na sobreposição espacial entre os indivíduos na paisagem florestal contínua. Por fim, no capítulo 04, eu avalio a existência e o intervalo temporal de movimentos periódicos dentro das áreas de vida. Os padrões de movimentos periódicos foram mais presentes e com alta significância da periodicidade diária em indivíduos na paisagem de manchas florestais do que na paisagem florestal, possivelmente ocasionada pelo maior efeito na patrulha territorial e no uso de manchas de recursos dentro de suas áreas de vida neste ambiente. Ao final da tese, apresento as conclusões gerais e as atividades acadêmicas de ensino e pesquisa desenvolvidas ao longo do meu período do doutorado. Em resumo, essa tese ressalta a importância em se considerar a influência do contexto de paisagem no movimento e organização espacial de uma população. Estas variações implicam em diferentes efeitos quando interligarmos a relação existente entre o movimento animal e sua função ecológica no ambiente, moldando o tempo e o local na qual esta função poderá ocorrer.
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.
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.
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Palavras-chave
Ecologia de movimento, Ecologia de paisagem, Ecologia de população, Movement ecology, Landscape ecology, Population ecology