Orientador: Roberto André Kraenkel / Coorientador: Renato Mendes Coutinho / Banca: Marcus Aloízio Martinez de Aguiar / Banca: Camilo Rodrigues Neto / Resumo: Muito é discutido dentro e fora do meio acadêmico a respeito do impacto que o desmatamento e a atividade humana de forma geral têm sobre a diversidade das paisagens naturais. Por se tratar de uma preocupação recente da perspectiva da escala de tempo da história da civilização, trata-se de um fenômeno cujos mecanismos ainda se encontram em pleno processo de esclarecimento, embora não haja dúvida de sua existência. Nesse contexto, as ferramentas matemáticas e computacionais podem fornecer contribuições substanciais para a sistematização e a descrição precisa das causas e efeitos envolvidos nesse processo, muitas vezes por meio de resultados importantes e pouco intuitivos. Por exemplo, podem-se criar modelos matemáticos que avaliem os efeitos da restrição de habitat nos chamados módulos de comunidade, fornecendo previsões relevantes para casos limite de sistemas biológicos reais. Apesar disso, ainda existem muitas lacunas teóricas na literatura subjacente. O seguinte trabalho procurou então contribuir para o caso particular do módulo de comunidade conhecido como Predação Intraguilda utilizando Equações Diferenciais Parciais do tipo Reação-Difusão. Após uma breve revisão bibliográfica de alguns modelos de Dinâmica de Populações, o estudo dessas equações se deu por métodos de aproximação das soluções. Além de integrações numéricas, utilizamos um método de aproximação baseado em princípios variacionais capaz de reproduzir os principais aspectos esperados das soluções das equações. ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Much is discussed within and outside the academic world about the impact that de-forestation and human activity in general have on the diversity of natural landscapes.Because it is a recent concern from the perspective of the time scale of the history ofcivilization, it is a phenomenon whose mechanisms are still in the process of clarification,although there is no doubt of its existence.In this context, mathematical and computational tools can provide substantial contri-butions to the systematization and precise description of the causes and effects involved inthis process, often through important and unintuitive results. For example, it is possibleto create mathematical models that evaluate the effects of habitat restriction on the so-calledcommunity modules, providing relevant predictions for limit cases of real biologicalsystems. Despite this, there are still many theoretical gaps in the underlying literature.The following work then sought to contribute to this in the particular case of thecommunity module known as Intraguild Predation using Reaction-Diffusion Partial Dif-ferential Equations. After a brief bibliographical review of some models of PopulationDynamics, the study of these equations was given by methods of approximation of thesolutions. In addition to numerical integrations, we used a method of approximationbased on variational principles capable of reproducing the main expected aspects of the solutions...(Complete abstract click electronic access bellop) / Mestre

Natural populations of small rodents fluctuate continually over time and the population dynamics of any living organism are shaped by both intrinsic and extrinsic factors. Small mammals populations can show a continuum dynamic activity, ranging from stability to regular cycles of variable amplitude. The species dynamics is also known to be influenced by the seasonal structure of the environment. The community of small mammals present in the Araucaria forest could present similar patterns to forests occurring in other temperate regions of the planet and the large seeds of Araucaria angustifolia (dominant tree) are consumed by a large array of vertebrates, mainly rodents and large birds, which act as seed dispersers and predators simultaneously. When species are very similar like the two most abundant of this community (Akodon montensis and Oligoryzomys nigripes) the outcome of competition is often the partitioning of resources such as habitat or food. Plant species are crucial for rodents, because they are the main food source for many species, and this particular relation between rodents and plants is crucial for the process of forest regeneration, since the regeneration development are associated with details on the role of each rodent species as a seed disperser or seed predator. There are a lot of important factors interfering in the regeneration process, and changes in these factors are manifested in variables such as density of tree individuals, basal area, floristic composition, and species richness and diversity. To analyse the populational aspects of the rodents in the area and identify correlations between the Araucaria angustifolia trees with rodent community, to evaluate arthropod-small mammals species association and test the relationship between natural forest regeneration and rodent community, we established a trapping grid of two hectares with 231 trap stations (11 X 21 configuration, 10m spacing). Every trapping series, which consisted of 6 days, traps were placed on the ground and a capture-mark-recapture program was carried out two times per season between November 2008 and August 2009. We followed Cormarck-Jolly-Seber (CJS) method to estimate population parameters and density was estimated for each trapping session. The mean of population density was used as a dependent variable in a linear regression to investigate possible relations between densities and extrinsic factors. The arthropod abundance was quantified with pitfall traps during four of the eight sample periods and we measured regeneration variables that could potentially influence the spatial distribution of the small mammals. The association between rodent and arthropod communities was compared with the similarity matrix based on rodent composition using simple Mantel tests and we used DCA analysis to ordinate sample units based on rodent community. Significance of the associations between regeneration and rodent community was tested by 1000 Monte Carlo permutations based on Pearson's correlation. The populations of the two most abundant rodents in the community (Akodon montensis and Oligoryzomys nigripes) were considered inconstant and their population variations could have indirect effects on other species. Our result suggests that these two species are the main small mammal present in the area and if extrinsic factors do not operate all the times as showed, it strongly suggests that there must be variation in spacing and dispersal behavior of these species or extrinsic factors can also be acting in indirect ways. The presence of the species Mus musculus indicates that this forest area had or still haves anthropic influence. In general, secondary forests provide important habitats and resources to the rodent community and are distinctly associated to the species. Although indirectly, our results indicate that there is a complex combination of regeneration predation/dispersal by rodents and it seems that generalist species might select habitat characteristics primarily at a site level because they are able to use different local factors that exist in a variety of landscapes. Based on our results we can assume that small mammals associated with herbaceous or shrub cover, particularly in riparian areas, will decline when deforestation remove this cover. We also provide initial insight for habitat features that are related to rodent community pointed out the correlations between numbers of individuals and natural regeneration.

Orientador: Roberto André Kraenkel / Banca: Marcone Corrêa Pereira / Banca: Fernando Fagundes Ferreira / Banca: Juliana Berbert / Banca: Maria Cristina Varriále / Resumo: A biologia matemática tem se tornado cada vez mais importante para se obter resultados qualitativos em ecologia. Particularmente, em ecologia espacial, pode-se perguntar como o espaço influencia a dinâmica de sistemas que apresentam biestabilidade, como em espécies obrigatoriamente mutualistas ou sujeitas ao efeito Allee. Apresentamos um método de aproximação de equações de reação e difusão para analisar estes e outros modelos. O método recupera resultados clássicos e também permite obter alguns novos, gerando bastante otimismo para aplicações futuras em casos mais complicados. / Abstract: Mathematical biology has become more and more important to obtain qualitative results in ecology. Specially, in spatial ecology, one may wonder how does space alter the dynamics in bistable systems, such as obligate mutualistic species and those under Allee effects. We present an approximation method for reaction-diffusion equations in order to analyze these and other models. The method recoups classical results whilst also allow us to obtainnew ones, giving an optimistic perspective for future applications in more complex cases / Mestre

Orientador: Wesley Augusto Conde Godoy / Coorientador: Patricia Jacqueline Thyssen / Banca: Aricio José Linhares / Banca: Carolina Reigada / Banca: Claudio José Von Zuben / Banca: Lucas Del Bianco Faria / Resumo: Moscas-varejeiras apresentam características biológicas complexas, e constituem excelentes modelos de organismos em estudos ecológicos, principalmente aqueles que envolvem processos matematicamente modeláveis. No presente estudo, foram coletados insetos necrófagos e selecionadas três espécies de Calliphoridae com o objetivo de estimar parâmetros demográficos de séries temporais, e estudar o comportamento dinâmico destas espécies. A abordagem proposta é de grande utilidade para a entomologia forense, principalmente no estado de São Paulo, onde há necessidade de utilização de novas ferramentas para a resolução de crimes, tendo em vista a crescente taxa de homicídios / Abstract: Blowflies have complex biological features, and are models of organisms with great value in ecological studies, mainly the ones that involve processes that can be mathematically modelled. In the present study, we carried out an extensive survey of necrophagic insects and selected three blowfly species to estimate demographic parameters of time series, and to study their dynamic behavior. We believe that the proposed approach will be valuable in the field of forensic entomology, mainly in São Paulo state, where the rising rates of homicides are cause of great concern, and impel the prompt utilization of novel tools to resolve crimes / Doutor

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Biológicas, Programa de Pós-Graduação em Zoologia, 2016. / Submitted by Albânia Cézar de Melo (albania@bce.unb.br) on 2016-04-28T16:42:08Z No. of bitstreams: 1 2016_WesleySilveiraRocha.pdf: 1736805 bytes, checksum: 59cf38669e63a0900a011189e7d0f4f0 (MD5) / Approved for entry into archive by Raquel Viana(raquelviana@bce.unb.br) on 2016-04-28T21:12:14Z (GMT) No. of bitstreams: 1 2016_WesleySilveiraRocha.pdf: 1736805 bytes, checksum: 59cf38669e63a0900a011189e7d0f4f0 (MD5) / Made available in DSpace on 2016-04-28T21:12:14Z (GMT). No. of bitstreams: 1 2016_WesleySilveiraRocha.pdf: 1736805 bytes, checksum: 59cf38669e63a0900a011189e7d0f4f0 (MD5) / Neste estudo foram investigadas as características populacionais, a palatabilidade e as relações miméticas entre Siderone galanthis e Callicore sorana em uma área de cerrado sensu stricto no Brasil central. Os resultados obtidos mostraram que estas espécies exibem um padrão de dinâmica populacional bastante semelhante entre si, com ambas as espécies ocorrendo durante a estação seca (abril a setembro) e atingindo picos populacionais em agosto em 2014 e 2015. Além disto, ambas as espécies mostraram fortes semelhanças nos tamanhos populacionais, no tempo de residência na área de estudos e padrões de dispersão. Experimentos de palatabilidade conduzidos com aranhas (Nephila clavipes) e lagartos (Tropidurus itambere) não indicaram a presença de compostos químicos defensivos, sugerindo que ambas as espécies são palatáveis para predadores. Estes resultados sugerem que Siderone galanthis e Callicore sorana não constituem um caso clássico de mimetismo Batesiano ou Mülleriano, mas podem constituir um caso de mimetismo de escape. Esta possibilidade também é sugerida pela grande quantidade de marcas de bicadas de aves encontradas nas asas destas borboletas, que indica que foram fortemente atacadas, mas escaparam dos ataques de aves insetívoras. Uma tentativa para testar a vantagem do mimetismo para estas borboletas em condições naturais, independentemente do tipo de mimetismo envolvido entre elas, também é apresentada. _______________________________________________________________________________________________ ABSTRACT / This study investigates some population traits, the palatability, and the mimetic relationship between Siderone galanthis and Callicore sorana in a site of cerrado sensu stricto in central Brazil. The results obtained showed that these butterflies exhibit a very similar population dynamics with both species occurring during the dry season (April to September) and reaching peak numbers in August in both 2014 and 2015 censuses. In addition, both butterflies showed similar population sizes, longevity (residence in the study site), and dispersal patterns. Palatability experiments conducted with spiders (Nephila clavipes) and lizards (Tropidurus itambere) did not indicate the presence of defensive chemicals, suggesting that both butterflies are palatable to predators. These results indicate that Siderone galanthis and Callicore sorana do not constitute a classic case of Batesian or Müllerian mimicry, but rather a case of escape mimicry. Such a possibility is supported by a large number of bird beak marks found on the wings of live butterflies, which indicate they were heavily attacked by escaped attacks of insectivorous birds. An attempt to test the advantage of mimicry for these butterflies in natural conditions, regardless the type of mimicry involved between them, is also reported.

Made available in DSpace on 2014-06-11T19:35:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-11Bitstream added on 2014-06-13T20:07:15Z : No. of bitstreams: 1 moretti_tc_dr_botib_parcial.pdf: 27000 bytes, checksum: ce411b9cc560f2657fddee4482450bf5 (MD5) Bitstreams deleted on 2015-06-25T13:01:00Z: moretti_tc_dr_botib_parcial.pdf,. Added 1 bitstream(s) on 2015-06-25T13:03:21Z : No. of bitstreams: 1 000648089_20160211.pdf: 26821 bytes, checksum: 3a960d20ec13ef803c8ffc9e931f3a09 (MD5) Bitstreams deleted on 2016-02-11T11:32:24Z: 000648089_20160211.pdf,. Added 1 bitstream(s) on 2016-02-11T11:33:01Z : No. of bitstreams: 1 000648089.pdf: 3040067 bytes, checksum: 6e164d8fa1054c636cc628e427838cf0 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Moscas-varejeiras apresentam características biológicas complexas, e constituem excelentes modelos de organismos em estudos ecológicos, principalmente aqueles que envolvem processos matematicamente modeláveis. No presente estudo, foram coletados insetos necrófagos e selecionadas três espécies de Calliphoridae com o objetivo de estimar parâmetros demográficos de séries temporais, e estudar o comportamento dinâmico destas espécies. A abordagem proposta é de grande utilidade para a entomologia forense, principalmente no estado de São Paulo, onde há necessidade de utilização de novas ferramentas para a resolução de crimes, tendo em vista a crescente taxa de homicídios / Blowflies have complex biological features, and are models of organisms with great value in ecological studies, mainly the ones that involve processes that can be mathematically modelled. In the present study, we carried out an extensive survey of necrophagic insects and selected three blowfly species to estimate demographic parameters of time series, and to study their dynamic behavior. We believe that the proposed approach will be valuable in the field of forensic entomology, mainly in São Paulo state, where the rising rates of homicides are cause of great concern, and impel the prompt utilization of novel tools to resolve crimes

Este trabalho é o resultado do nosso interesse em estudar os princípios fundamentais que envolvem a questão do desenvolvimento sustentável, mais especificamente a questão do gerenciamento econômico ótimo de recursos biológicas renováveis. Modificamos modelos populacionais extremamente simples incluímos retirada contínua. Em relação à pesca, examinamos com maior detalhe o modelo de produção geral de Schaefer. Calculamos e analisamos a estabilidade linear em cada ponto de equilíbrio dos sistemas com os quais trabalhamos. O comportamento dinâmico global é obtido pela integração numérica. A partir da modelagem de exploração de recursos biológicos, introduzimos o conceito de produção máxima sustentável (MSY), que é o objetivo de muitas agências de gerenciamento de recursos renováveis. Após observarmos a ineficiência da NI SY por não incorporar os custos de exploração de recursos, estudamos o modelo bioeconômico de Gordon, e a definição de produção máxima econômica (M EY). Aprendemos da teoria econômica padrão o conceito de "desconto" , que reflete o valor do tempo, e então o problema dinâmico é formulado para determinar a função que ma.ximize o valor presente descontado. Após uma breve discussão sobre o problema variacionallinear e a teoria de controle, concluímos que, ao considerar os custos de exploração e o valor do tempo, a política de retirada ótima consiste na política de aproximação mais rápida (M RAP) ao nível do estoque de equilíbrio ótimo, ao qual corresponde a produção econômica ótima (OEY). Como casos especiais, observamos que se ambos os custos de exploração e a taxa de desconto forem nulos, então a NI SY é ótima; e se a taxa de desconto for zero mas o custo de exploração for maior que zero, então a 1\1 EY é ótima. Finalmente, incluímos também um exemplo baseado no modelo de Schaefer, no qual podemos observar que o nível do estoque de equilíbrio ótimo pode ser muito sensível à taxa do desconto. / We are interested in studying the fundamental principies underlying the problem of sustainable development, more specifically the economics of optimal management of biological renewable resources harvesting. Vi/e modify extremely simple population models to allow for continuous harvesting. Concerning fisheries, we examine in greater detail the Schaefer's general production model. We calculate and develop the linear stability analysis for each equilibrium state of the systems we are concerned with. The global dynamic behavior is obtained by numerical integration. From the modeling of biological resource exploitation, we introduce the Maximum Sustainable Yield (MSY) concept, which is the objective of many resource management agencies. After realizing the failure of MSY to incorporate costs of resource exploitation, we study the bioeconomic Gordon's model and the definition of Maximum Economic Yíeld (MEY). We learn from standard economic theory the "discounting" concept, for reflecting the "value of time" , and so the dynamic problem is formulated as to determine the function effort that maximizes the discounted present value. After a brief discussion about linear variational problem and control theory, we conclude that, when both exploitation costs and value of time are considered, the optimal harvest policy consists of the most rapid approach policy (MRAP) to the optimal equilibrium stock level, corresponding to the Optimal Economic Yield (OEY). As special cases, we observe that if both exploitation costs and the discount rate are zero, then MSY is optimal; and if the discount rate is zero but the costs are greater than zero, then MEY is optimal. Finally, we also include examples based on the Schaefer model, from which we can observe that the optimal equilibrium stock level can be quite sensitive to the rate of discount.

Gubernatrix cristata, o cardeal-amarelo, é uma espécie de ave rara do Pampa. Ele tem uma distribuição geográfica restrita ao sul da América do Sul (Uruguai, Argentina e sul do Brasil) e é exclusivo deste bioma. Quatorze viagens de campo foram feitas de Abril de 2006 a março de 2009, em uma tentativa de encontrar indivíduos e coletar amostras para análise genética. Desenvolvemos dez marcadores microssatélites isolados a partir desta espécie e caracterizamos a sua variabilidade alélica. O número de alelos observados em cada locus variou de 4 a 14, com uma média de 7,5 alelos por locus. Os microssatélites mostraram-se úteis em revelar os níveis de diversidade de G. cristata e, portanto, podem ser usados para explorar a estrutura genética das populações dispersas ao longo de sua distribuição geográfica atual. Um total de 72 amostras de cardeal-amarelo foi usado neste estudo, 59 foram de amostras contemporâneas e 13 amostras de espécimes de museu. Nós acessamos a diversidade genética da espécie através dos dez loci polimórficos de microssatélites nucleares do G. cristata desenvolvidos nesse estudo e através de um fragmento do gene ND2 do DNA mitocondrial. Encontramos apenas três haplótipos com diversidade nucleotídica e haplotípica respectivamente igual a π = 0,00277 e Hd = 0,6219. O Fst (0,00340) e Nm (73,18) mostraram uma fraca estruturação com pouca diferenciação genética. A estatística Fs de Fu foi significativamente diferente de zero (2,248) e D de Tajima foi positivo (2,17506). Ambos os testes mostraram um indicativo de evidência provável de uma diminuição no tamanho da população e/ou seleção equilibradora. As análises usando o "no admixture model" e um grande burnin (500000) não resultaram em clustering dos indivíduos. Devido a esse resultado nenhuma atribuição individual a uma área geográfica foi possível. O presente estudo auxilia na compreensão das necessidades de conservação do cardeal-amarelo, fornecendo informações sobre a diversidade genética e estruturação populacional ao longo de sua área de distribuição. Embora não tenhamos encontrado estruturação dentro da nossa área de estudo, é preciso mais estudos, analisando a diversidade genética e estruturação populacional em toda a área de distribuição da espécie, e adicionando mais amostras de animais silvestres da população de La Pampa e de Corrientes. O mapa da área de distribuição do cardeal-amarela parece estar ultrapassado devido à situação cada vez mais crítica que a espécie está enfrentando na natureza. Dada a recente falta de conhecimento sobre sua distribuição e seu estado de conservação em seu habitat natural, decidimos modelar a distribuição potencial da espécie. A principal idéia por trás dessa informação era propor estratégias para sua conservação. Para melhor alcançar esse objetivo, focamos nossa pesquisa especificamente em a) localizar as populações silvestres desta espécie no Rio Grande do Sul, Uruguai e Argentina, e b) identificar as áreas de ocorrência do cardeal-amarelo que poderiam ser transformadas em áreas protegidas. Todos os registros georeferenciados de G. cristata foram extraídos de diferentes fontes: através de trabalho de campo, peles de museu, literatura e bases de dados da Internet. Para modelar a distribuição da espécie, foram selecionadas 20 variáveis ambientais e o aplicativo de modelagem Maxent v. 3.3.2. Mapas de distribuição histórica e atual de G. cristata foram criados usando DIVA GIS. O modelo que melhor prediz o índice relativo de adequação ambiental para a espécie é o modelo onde a AUC resultante sobre dados de testes foi 0,868. O resultado do teste de jackknife acerca da importância das variáveis mostrou que a variável ambiental com maior ganho quando usada isoladamente é bio1_sa_30s_cut (temperatura média anual) que, portanto, parece ter as informações mais úteis por si só. A variável ambiental que mais diminui o ganho quando é omitida é alt_sa_30s_cut (altitude) que, portanto, parece ter o máximo de informação que não está presente nas outras variáveis. Se o objetivo de pesquisas futuras do cardeal-amarelo em sua área de distribuição for detectar outras populações, então as áreas preditas em ter elevada adequabilidade relativa no modelo espacial são um bom ponto de partida para a pesquisa mais direcionada. A pressão da caça sobre a espécie é tão grande que o cardeal-amarelo hoje em dia parece ser encontrado apenas em áreas de difícil acesso. Muitas das áreas adequadas para a espécie mostrada pelo modelo podem ainda conter populações e também podem ser usadas como áreas-chave para futuras reintroduções dentro do programa de conservação do cardeal-amarelo. / Gubernatrix cristata, the yellow cardinal, is a rare bird species from the Pampas grassland. It has a restricted geographical distribution in southern South America and is unique to this Biome (Uruguay, Argentina, and Southern Brazil). Fourteen field trips were made from April 2006 to March 2009 in an attempt to find individuals and collect samples for genetic analysis. We developed ten microsatellite markers isolated from this species and the characterization of their allele variability. The number of alleles observed for each locus ranged from 4 to 14, with an average of 7.5 alleles per locus. The microsatellites proved to be useful in revealing levels of diversity in G. cristata, and thus can be used to explore the genetic structure of scattered populations across its present geographic range. A total of 72 yellow cardinal samples was taken in this study, 59 were from contemporary specimens and 13 samples were from museum specimens. We accessed the species genetic diversity through ten polymorphic nuclear microsatellite loci of G. cristata and a ND2 mtDNA fragment. We found only three haplotypes with nucleotide and haplotype diversity equals to π = 0.00277 and Hd = 0.6219. The Fst (0,00340) and Nm (73,18) shown a weak structuring with little genetic differentiation. Fu's Fs statistic was significantly different from zero (2,248) and Tajima's D was positive (2,17506). Both tests showed likely evidence indicating a decrease in population size and/or balancing selection. Analyses using the “no admixture model” and a larger burn-in (500000) yielded no clustering of individuals. Due to this result no individual assignment to any geographical area was possible. The present study assists in understanding the conservation needs for yellow cardinal by providing information on the genetic diversity and population structuring along its distribution range. Although we found no structuring within our study area, further study is needed, examining the genetic diversity and population structuring throughout the species’ range, adding more samples from wild animals from La Pampa population and Corrientes. The yellow cardinal distribution range map seems to be outdated because of the increasingly critical situation the species is facing in nature. Given the recent lack of knowledge regarding its distribution and its state of preservation in its natural habitat we decided to model the species potential distribution. The main idea behind this information was to propose strategies for their conservation. To better achieve that target we specifically focused our research on a) locating wild populations of this species in Rio Grande do Sul, Uruguay and Argentina, and b) identifying areas of occurrence of yellow cardinal that could be turned into protected areas. We extracted all georeferenced G. cristata records from different sources: field working, museum skins, literature, and internet datasets. To model the species distributions, 20 environmental predictors were selected. To model the species distributions we selected the modeling application Maxent v. 3.3.2. Historical and current distribution maps of G. cristata were created using DIVA GIS. The model that best predicts the relative index of environmental suitability for the species is the model where resulting AUC on test data was 0.868. The results of the jackknife test of variable importance showed that the environmental variable with highest gain when used in isolation is bio1_sa_30s_cut (Annual Mean Temperature), which therefore appears to have the most useful information by itself. The environmental variable that decreases the gain the most when it is omitted is alt_sa_30s_cut (Altitude), which therefore appears to have the most information that isn't present in the other variables. If the objective of future surveys of the yellow cardinal in its distribution range is to detect other populations, then areas predicted to have high relative suitability in the spatial model is a good starting point for further targeted survey. The hunting pressure on the species is so great that the yellow cardinal nowadays seems to be only found in areas of difficult access. Many of the areas suitable for the species shown by the model may still contain populations and can also be used as key areas for future reintroductions into the yellow cardinal conservation program.

Natural populations of small rodents fluctuate continually over time and the population dynamics of any living organism are shaped by both intrinsic and extrinsic factors. Small mammals populations can show a continuum dynamic activity, ranging from stability to regular cycles of variable amplitude. The species dynamics is also known to be influenced by the seasonal structure of the environment. The community of small mammals present in the Araucaria forest could present similar patterns to forests occurring in other temperate regions of the planet and the large seeds of Araucaria angustifolia (dominant tree) are consumed by a large array of vertebrates, mainly rodents and large birds, which act as seed dispersers and predators simultaneously. When species are very similar like the two most abundant of this community (Akodon montensis and Oligoryzomys nigripes) the outcome of competition is often the partitioning of resources such as habitat or food. Plant species are crucial for rodents, because they are the main food source for many species, and this particular relation between rodents and plants is crucial for the process of forest regeneration, since the regeneration development are associated with details on the role of each rodent species as a seed disperser or seed predator. There are a lot of important factors interfering in the regeneration process, and changes in these factors are manifested in variables such as density of tree individuals, basal area, floristic composition, and species richness and diversity. To analyse the populational aspects of the rodents in the area and identify correlations between the Araucaria angustifolia trees with rodent community, to evaluate arthropod-small mammals species association and test the relationship between natural forest regeneration and rodent community, we established a trapping grid of two hectares with 231 trap stations (11 X 21 configuration, 10m spacing). Every trapping series, which consisted of 6 days, traps were placed on the ground and a capture-mark-recapture program was carried out two times per season between November 2008 and August 2009. We followed Cormarck-Jolly-Seber (CJS) method to estimate population parameters and density was estimated for each trapping session. The mean of population density was used as a dependent variable in a linear regression to investigate possible relations between densities and extrinsic factors. The arthropod abundance was quantified with pitfall traps during four of the eight sample periods and we measured regeneration variables that could potentially influence the spatial distribution of the small mammals. The association between rodent and arthropod communities was compared with the similarity matrix based on rodent composition using simple Mantel tests and we used DCA analysis to ordinate sample units based on rodent community. Significance of the associations between regeneration and rodent community was tested by 1000 Monte Carlo permutations based on Pearson's correlation. The populations of the two most abundant rodents in the community (Akodon montensis and Oligoryzomys nigripes) were considered inconstant and their population variations could have indirect effects on other species. Our result suggests that these two species are the main small mammal present in the area and if extrinsic factors do not operate all the times as showed, it strongly suggests that there must be variation in spacing and dispersal behavior of these species or extrinsic factors can also be acting in indirect ways. The presence of the species Mus musculus indicates that this forest area had or still haves anthropic influence. In general, secondary forests provide important habitats and resources to the rodent community and are distinctly associated to the species. Although indirectly, our results indicate that there is a complex combination of regeneration predation/dispersal by rodents and it seems that generalist species might select habitat characteristics primarily at a site level because they are able to use different local factors that exist in a variety of landscapes. Based on our results we can assume that small mammals associated with herbaceous or shrub cover, particularly in riparian areas, will decline when deforestation remove this cover. We also provide initial insight for habitat features that are related to rodent community pointed out the correlations between numbers of individuals and natural regeneration.

Natural populations of small rodents fluctuate continually over time and the population dynamics of any living organism are shaped by both intrinsic and extrinsic factors. Small mammals populations can show a continuum dynamic activity, ranging from stability to regular cycles of variable amplitude. The species dynamics is also known to be influenced by the seasonal structure of the environment. The community of small mammals present in the Araucaria forest could present similar patterns to forests occurring in other temperate regions of the planet and the large seeds of Araucaria angustifolia (dominant tree) are consumed by a large array of vertebrates, mainly rodents and large birds, which act as seed dispersers and predators simultaneously. When species are very similar like the two most abundant of this community (Akodon montensis and Oligoryzomys nigripes) the outcome of competition is often the partitioning of resources such as habitat or food. Plant species are crucial for rodents, because they are the main food source for many species, and this particular relation between rodents and plants is crucial for the process of forest regeneration, since the regeneration development are associated with details on the role of each rodent species as a seed disperser or seed predator. There are a lot of important factors interfering in the regeneration process, and changes in these factors are manifested in variables such as density of tree individuals, basal area, floristic composition, and species richness and diversity. To analyse the populational aspects of the rodents in the area and identify correlations between the Araucaria angustifolia trees with rodent community, to evaluate arthropod-small mammals species association and test the relationship between natural forest regeneration and rodent community, we established a trapping grid of two hectares with 231 trap stations (11 X 21 configuration, 10m spacing). Every trapping series, which consisted of 6 days, traps were placed on the ground and a capture-mark-recapture program was carried out two times per season between November 2008 and August 2009. We followed Cormarck-Jolly-Seber (CJS) method to estimate population parameters and density was estimated for each trapping session. The mean of population density was used as a dependent variable in a linear regression to investigate possible relations between densities and extrinsic factors. The arthropod abundance was quantified with pitfall traps during four of the eight sample periods and we measured regeneration variables that could potentially influence the spatial distribution of the small mammals. The association between rodent and arthropod communities was compared with the similarity matrix based on rodent composition using simple Mantel tests and we used DCA analysis to ordinate sample units based on rodent community. Significance of the associations between regeneration and rodent community was tested by 1000 Monte Carlo permutations based on Pearson's correlation. The populations of the two most abundant rodents in the community (Akodon montensis and Oligoryzomys nigripes) were considered inconstant and their population variations could have indirect effects on other species. Our result suggests that these two species are the main small mammal present in the area and if extrinsic factors do not operate all the times as showed, it strongly suggests that there must be variation in spacing and dispersal behavior of these species or extrinsic factors can also be acting in indirect ways. The presence of the species Mus musculus indicates that this forest area had or still haves anthropic influence. In general, secondary forests provide important habitats and resources to the rodent community and are distinctly associated to the species. Although indirectly, our results indicate that there is a complex combination of regeneration predation/dispersal by rodents and it seems that generalist species might select habitat characteristics primarily at a site level because they are able to use different local factors that exist in a variety of landscapes. Based on our results we can assume that small mammals associated with herbaceous or shrub cover, particularly in riparian areas, will decline when deforestation remove this cover. We also provide initial insight for habitat features that are related to rodent community pointed out the correlations between numbers of individuals and natural regeneration.