Human activities have being responsible for the global environmental changes, resulting in an increase number of incident of vector- and rodent-borne diseases worldwide. Rodents and arthropods-borne viruses are important globally emerging and re-emerging viruses and most of them are RNA viruses. Efficient and early diagnosis of these infections are very important to prevent their spread, to improve clinical management of the patients, as wells to protect livestock and domestic animals. Currently, available diagnostic methods such as immunoassays, polymerase chain reaction and virus isolation can detect only one or few viruses in a single assay. The DNA microarray platform has emerged as diagnostic tool suitable for high throughput screening of pathogenic agents. The aim of this study was to develop a DNA microarray platform (RoboArboVirusChip) for detecting rodent- and arthropod-borne viruses, which belong to seven families: Bunyaviridae (genera Orthobunyavirus, Nairovirus and Phlebovirus), Flaviviridae (genus Flavivirus), Togaviridae (genus Alphavirus), Reoviridae (genera Orbivirus, Seadornavirus and Coltvivirus), Rhabdoviridae (genera Vesiculovirus and Ephemerovirus), and Asfarviridae (genus Asfarvirus). Specific oligonucleotide probes of 60-mer (n=4209) targeting 412 virus species and generic probes of 25-35-mer (n=87) targeting viruses at the genus level were designed. A total of 17 reference viruses belonging to the Bunyaviridae, Flaviviridae, Rhabdoviridae and Togaviridae families were used to standardize RoboArboVirusChip. All reference viruses were specifically detected without any cross hybridization; however, the generic probes were not able to identify the viruses at the genus level. The RoboArboVirusChip was able to specifically identify four viruses contained in three different mixtures: i) virus of different families, ii) virus of the Flavivirus genus, and iii) the Dengue virus (DENV) serotypes. The four DENV serotypes were use to evaluate the sensitivity of the RoboArboVirusChip, which was able to detect a minimum of 25 RNA copies/mL of the viruses, confirming its high sensitivity. The applicability of the RoboArboVirusChip to detect viruses in clinical samples was tested with serum samples obtained from dengue suspected cases (four positive cases and 40 negative cases). DENV was detected in the four positive serum samples, while in the 40 negative serum samples, it was not detected any virus. The results obtained in this study suggest that the RoboArboVirusChip platform could be a useful tool for early diagnosis of robovirus and arbovirus infections during epidemic outbreaks, helping in the rapid implementation of disease containment strategies / As atividades humanas têm sido responsável por mudanças ambientais globais, resultando num aumento do número de casos de doenças transmitidas por vetores e roedores em todo o mundo. Os vírus transmitidos por roedores e artrópodes são vírus emergentes e re-emergentes de importância global, sendo que a maioria deles são vírus de RNA. O diagnóstico eficiente e precoce dessas infecções são muito importantes para evitar a sua propagação, para melhorar o manejo clínico dos pacientes e também, para proteger o gado e os animais domésticos. Atualmente, os métodos de diagnóstico disponíveis, tais como os imunoensaios, a reação em cadeia da polimerase e o isolamento viral podem detectar apenas um ou poucos vírus em um único ensaio. A plataforma de microarranjo de DNA tem surgido como uma ferramenta de diagnóstico apropriada para o monitoramento em larga escala de agentes patogênicos. O objetivo deste estudo foi desenvolver uma plataforma de microarranjo de DNA (RoboArboVirusChip) para a detecção de vírus transmitidos por roedores e artrópodes, os quais pertencem a sete famílias: Bunyaviridae (gêneros Orthobunyavirus, Nairovirus e Phlebovírus), Flaviviridae (gênero Flavivirus), Togaviridae (gênero Alphavirus), Reoviridae (gênero Orbivirus, Seadornavirus e Coltvivirus), Rhabdoviridae (géneros Vesiculovirus e Ephemerovirus), e Asfarviridae (gênero Asfarvirus). Sondas oligonucleotídicas de 60-mer (n=4209) específicas contra 412 espécies virais, e sondas genéricas de 25-35-mer (n=87) para detecção de vírus a nível do gênero foram desenhados. Um total de 17 vírus de referência, pertencentes às famílias Bunyaviridae, Flaviviridae, Rhabdoviridae e Togaviridae foram utilizados para padronizar o RoboArboVirusChip. Todos os vírus de referência foram detectados especificamente sem apresentação de hibridação cruzada, porem as sondas genéricas não foram capazes de detectar os vírus a nível do gênero. O RoboArboVirusChip foi capaz de identificar especificamente quatro vírus contidos em diferentes misturas: i) vírus de diferentes famílias, ii) vírus pertencentes ao gênero a Flavivirus, e iii) os sorotipos do vírus da dengue (DENV). Os quatro sorotipos do DENV foram utilizados para determinar a sensibilidade do RoboArboVirusChip, o qual foi capaz de detectar um mínimo de 25 copias de RNA/mL. A aplicabilidade do RoboArboVirusChip para detectar vírus em amostras clínicas foi avaliada testando amostras de soro de pacientes com suspeita de dengue (quatro casos positivos e 40 casos negativos). Os resultados obtidos neste estudo sugerem que o RoboArboVirusChip poderá ser uma ferramenta útil para o diagnóstico precoce da infecção causada por robovírus e arbovírus, auxiliando na rápida implementação de estratégias de contenção das doenças causadas por esses vírus

Este trabalho foi realizado numa paisagem composta por 7 diferentes fisionomias de cerrado e uma floresta homogênea de eucaliptos, adjacente ao cerrado. Durante 12 meses amostrou-se os mamíferos mensalmente, por 3 noites consecutivas, procurando cobrir as variações sazonais de períodos secos e chuvosos, utilizando-se 2 tipos de armadilhas para os pequenos mamíferos: gaiola, dispostas ao longo das trilhas, de 25 em 25m, totalizando 114 armadilhas, amostrando todas diferentes fisionomias; e uma estação de pitfall, com 4 baldes de 40cm cada um, em cada fisionomia. O esforço de coleta foi de 4.896 trapnigths e 324 estações/ dia de pitfall, onde capturou-se 121 indivíduos de 12 gêneros, sendo 8 de roedores (Oligoryzomys sp, Calomys sp, Akodon sp, Oryzomys sp, Bolomys lasiurus, Pseudoryzomys simplex, Oxymicterus sp, Nectomys squamipes) e 4 de marsupiais (Didelphis albiventris, Marmosa sp, Gracilinanus microtarsus, Micoureus cinereus). A espécie dominante da comunidade é do gênero Oligoryzomys sp. O N. squamipes aparece sempre intimamente relacionado à água, já os gêneros B. lasiurus, Pseudoryzomys sp, Oxymicterus sp ocorrem em regiões de campo aberto. Os marsupiais G. microtarsus e Marmosa sp preferem fisionomias arbustivas de cerrado, já o M. cinereus, P. opossum, e D. albiventris preferem formações mais florestais, sendo este último, ao lado do Oligoryzomys sp os únicos a utilizar o reflorestamento. O maior número de capturas ocorreu no período seco e o nímero de roedores capturados foi muito maior que o de marsupiais. O maior valor de H’ apareceu na fisionomia de mata de transição entre cerradão e floresta ripária. Apesar do pitfall parecer um método muito mais eficiente que as armadilhas de gaiola, este estudo mostrou que os dois métodos são complementares, pois aquelas espécies que são capturadas nos pitfalls, com raras exceções, são capturadas também pelas gaiolas. As espécies de menor tamanho corporal foram capturadas nos pitfalls, como Oligoryzomys sp, Calomys sp, Gracilinanus microtarsus, Marmosa sp, já aquelas de maior tamanho corporal foram capturadas nas gaiolas, como Nectomys squamipes, Pseudoryzomys simplex, Oryzomys sp, Oxymicterus sp, Micoureus cinereus, Didelphis albiventris. Somente duas espécies foram capturadas tanto nas armadilhas quanto nos pitfalls, o Akodon sp e o Bolomys lasiurus. O cálculo do índice da Jaccard (= 0,17) forneceu um resultado que corrobora a idéia de que os dois tipos de armadilhas são complementares num estudo da comunidade de pequenos mamíferos. / The work has been performed in a landscape coposed of seven different Brazilian savanna physiognomie and an eucalyptus forest, adjacent of the Brazilian savanna. Small mammals, during 12 moths, were sampled, every 30 days for 3 consecutive nights, in dry and wet seasons, through 2 kinds of small mammal traps: Tomahawk style, arranged along trails, every twenty 5 meters, amounting a 114 traps sampling all physiognomies; and a pitfall satation, with four 40 centimeter deep buckets each, in each physiognomy. The capture effort was 4 896 tapnights and 324 pitfall/stations/day where a 121 individuals were captured, in 12 genera, with 8 rodents (Oligoryzomys sp, Calomys sp, Akodon sp, Oryzomys sp, Bolomys lasiurus, Pseudorizomys simplex, Oxymicterus sp, Nectomys squamipes) and 4 marsupials (Didelphis albiventris, Marmosa sp, Gracilinanus microtarsus, Micouerus cinereus). The community dominant specie is Oligoryzomys sp. The N.squamipes always appears closely related to water. In contrast, B. lasiurus, P. simplex and Oximycterus sp occur in open field regions. The marsupials G. microtarsus and Marmosa sp prefer Brazilian savannas shrubby vegetation, whereas M. cinereus, P. opossum and D. albiventris commonly use forested vegetation, and the llatter, side with the Oligoryzomys sp are the only ones to exploit the reforest areas. The largest number of captures occurred in the transition forest between the cerradão and the riparian forest. Despite of the fact that, pitfalls may seem a much more efficient method than Tomahawk traps themselves, said work has proved both methods to be complementary for those species were captured through pitfalls, with rare exceptions, were captured through Tomahawk traps as well. The smaller body mass species were captured through pitfalls, like Oligoryzomys sp, Calomys sp, G. microtarsus, Marmosa sp, whereas the bigger body mass ones were captured through Tomahawk traps, such as N. squamipes, P. simplex, Oryzomys sp, Oxymicterus sp, M. cinereus, D. albiventris. Only two species were captured through both methods Akodon sp and B. lasiurus. The Jaccard index (=0,17) performed a result that corroborates the idea that the two kinds of traps are complementary in a small mammals community study.

Este trabalho foi realizado numa paisagem composta por 7 diferentes fisionomias de cerrado e uma floresta homogênea de eucaliptos, adjacente ao cerrado. Durante 12 meses amostrou-se os mamíferos mensalmente, por 3 noites consecutivas, procurando cobrir as variações sazonais de períodos secos e chuvosos, utilizando-se 2 tipos de armadilhas para os pequenos mamíferos: gaiola, dispostas ao longo das trilhas, de 25 em 25m, totalizando 114 armadilhas, amostrando todas diferentes fisionomias; e uma estação de pitfall, com 4 baldes de 40cm cada um, em cada fisionomia. O esforço de coleta foi de 4.896 trapnigths e 324 estações/ dia de pitfall, onde capturou-se 121 indivíduos de 12 gêneros, sendo 8 de roedores (Oligoryzomys sp, Calomys sp, Akodon sp, Oryzomys sp, Bolomys lasiurus, Pseudoryzomys simplex, Oxymicterus sp, Nectomys squamipes) e 4 de marsupiais (Didelphis albiventris, Marmosa sp, Gracilinanus microtarsus, Micoureus cinereus). A espécie dominante da comunidade é do gênero Oligoryzomys sp. O N. squamipes aparece sempre intimamente relacionado à água, já os gêneros B. lasiurus, Pseudoryzomys sp, Oxymicterus sp ocorrem em regiões de campo aberto. Os marsupiais G. microtarsus e Marmosa sp preferem fisionomias arbustivas de cerrado, já o M. cinereus, P. opossum, e D. albiventris preferem formações mais florestais, sendo este último, ao lado do Oligoryzomys sp os únicos a utilizar o reflorestamento. O maior número de capturas ocorreu no período seco e o nímero de roedores capturados foi muito maior que o de marsupiais. O maior valor de H’ apareceu na fisionomia de mata de transição entre cerradão e floresta ripária. Apesar do pitfall parecer um método muito mais eficiente que as armadilhas de gaiola, este estudo mostrou que os dois métodos são complementares, pois aquelas espécies que são capturadas nos pitfalls, com raras exceções, são capturadas também pelas gaiolas. As espécies de menor tamanho corporal foram capturadas nos pitfalls, como Oligoryzomys sp, Calomys sp, Gracilinanus microtarsus, Marmosa sp, já aquelas de maior tamanho corporal foram capturadas nas gaiolas, como Nectomys squamipes, Pseudoryzomys simplex, Oryzomys sp, Oxymicterus sp, Micoureus cinereus, Didelphis albiventris. Somente duas espécies foram capturadas tanto nas armadilhas quanto nos pitfalls, o Akodon sp e o Bolomys lasiurus. O cálculo do índice da Jaccard (= 0,17) forneceu um resultado que corrobora a idéia de que os dois tipos de armadilhas são complementares num estudo da comunidade de pequenos mamíferos. / The work has been performed in a landscape coposed of seven different Brazilian savanna physiognomie and an eucalyptus forest, adjacent of the Brazilian savanna. Small mammals, during 12 moths, were sampled, every 30 days for 3 consecutive nights, in dry and wet seasons, through 2 kinds of small mammal traps: Tomahawk style, arranged along trails, every twenty 5 meters, amounting a 114 traps sampling all physiognomies; and a pitfall satation, with four 40 centimeter deep buckets each, in each physiognomy. The capture effort was 4 896 tapnights and 324 pitfall/stations/day where a 121 individuals were captured, in 12 genera, with 8 rodents (Oligoryzomys sp, Calomys sp, Akodon sp, Oryzomys sp, Bolomys lasiurus, Pseudorizomys simplex, Oxymicterus sp, Nectomys squamipes) and 4 marsupials (Didelphis albiventris, Marmosa sp, Gracilinanus microtarsus, Micouerus cinereus). The community dominant specie is Oligoryzomys sp. The N.squamipes always appears closely related to water. In contrast, B. lasiurus, P. simplex and Oximycterus sp occur in open field regions. The marsupials G. microtarsus and Marmosa sp prefer Brazilian savannas shrubby vegetation, whereas M. cinereus, P. opossum and D. albiventris commonly use forested vegetation, and the llatter, side with the Oligoryzomys sp are the only ones to exploit the reforest areas. The largest number of captures occurred in the transition forest between the cerradão and the riparian forest. Despite of the fact that, pitfalls may seem a much more efficient method than Tomahawk traps themselves, said work has proved both methods to be complementary for those species were captured through pitfalls, with rare exceptions, were captured through Tomahawk traps as well. The smaller body mass species were captured through pitfalls, like Oligoryzomys sp, Calomys sp, G. microtarsus, Marmosa sp, whereas the bigger body mass ones were captured through Tomahawk traps, such as N. squamipes, P. simplex, Oryzomys sp, Oxymicterus sp, M. cinereus, D. albiventris. Only two species were captured through both methods Akodon sp and B. lasiurus. The Jaccard index (=0,17) performed a result that corroborates the idea that the two kinds of traps are complementary in a small mammals community study.

Livestock grazing is a common and extensive land use practice in the United States occurring in a wide range of habitat types. As such, livestock grazing has the potential to alter ecosystem structure, function and community composition. The primary component (Chapter 1) of this thesis examined the effects of cattle grazing in a San Joaquin Valley grassland on two target taxa: reptiles and small mammals. The study took place on the Chimineas Unit of the Carrizo Ecological Reserve, San Luis Obispo County, California during Fall 2009 and Spring 2010. These taxa were sampled on matched pairs of two grazed and two ungrazed sites. Live trapping methods appropriate to sampling reptiles (coverboards and pit fall traps) and small mammals (Sherman live traps) were used to determine species richness and abundance of these taxa. Uta stansburiana (side-blotched lizard) abundances were greatest on Ungrazed1 (Fall: 1.75±0.49 captures/night, Spring: 3.58±0.35 captures/night). In addition, Chaetodipus californicus (Spiny pocket mouse) abundance was also greatest on Ungrazed1. Population estimates generated by Program CAPTURE suggest C. californicus could be 6.27 times more abundant on Ungrazed1 than Grazed1. However, sample size issues and site level effects confounded and made it difficult to determine significant differences between the grazed and ungrazed treatments for both reptile and small mammal taxa. Habitat structure at these sites was also evaluated including small mammal burrow abundance and vegetation structure. Again, differences between the grazed and ungrazed pasture could not be discerned because of site level effects occurring among matched pairs. As such, this thesis illustrates the difficulty in studying grazing and its potential effects on biotic systems because an array of variables can make unclear the differences between grazed and ungrazed areas. As a follow up study (Chapter 2) I used logistic regression to model U. stansburiana presence to examine possible sources of variation observed at trapping array locations utilized in the main study (Chapter 1). Shrubs exhibited a quasi-complete separation of data points and the three best models included: 1) Bare soil cover (AICc = 28.12), 2) Holes (AICc = 29.76), and 3) Bare soil cover + Holes (AICc = 29.90). Shrubs, bare soil cover and small mammal burrow density were all positively associated with U. stansburiana presence at array locations. Although species have general habitat requirements based upon their ecology and evolution, variations in habitat utilization exists depending upon the resources present at a specific location. Quantifying basic ecological information on a site specific basis is important to managing populations by identifying important resources and habitat components utilized by a given species on a given site.

Since pastoralism began in Australia???s rangelands, the number of artificial watering points (AWPs) has increased dramatically, such that today, few areas of rangeland are further than 10 km from water. This increased availability of water has caused many ecological impacts. Unfortunately, such impacts are poorly understood in the context of an Australian conservation reserve, thus hindering strategic management. This study examined the spatial distribution of vertebrate (kangaroos, small mammals, lizards and avifauna) and vegetative variables around open AWPs as well as AWPs that have been closed since pastoralism (sheep-grazing) ceased nearly thirty years ago in Sturt National Park, arid New South Wales. The study also examined vertebrate use of AWPs, with a particular emphasis on kangaroos and avifauna. The study revealed that most variables showed few differences in spatial distribution with distance from open and closed AWPs, thus suggesting that the observed piospheric impacts were primarily attributable to historical sheep-grazing. Indeed, piospheric patterns were weak suggesting some recovery over the last thirty years. That kangaroos did not exhibit water-focused grazing is no surprise, since despite their regular use of AWPs, particularly during hot, dry times, the current spatial arrangement of AWPs facilitates regular travel to, and from, such resources allowing kangaroos, like much other fauna, to distribute themselves in relation to food and shelter preferences rather than in relation to water supply. In contrast, the majority of avifaunal groups (excluding ground-dwelling species) were clustered around open AWPs, often irrespective of season, because of food and water requirements. Such spatial concentrations of avifauna are thought to cause a range of interspecific effects. Experimental AWP closure and GIS modelling showed that whilst closure of AWPs will increase the average distance to water, which will have key benefits, the majority of areas in Sturt National Park would still be accessible to most water-dependent species even if all unused AWPs were closed. Strategic retention of AWPs to replace water sources lost since European settlement, aid threatened and migratory species??? conservation and enhance nature-based tourism opportunities is thus recommended and an example of a strategic management and monitoring plan outlined.

The adaptive evolutionary potential of a species or population to cope with omnipresent environmental challenges is based on its genetic variation. Variability at immune genes, such as the major histocompatibility complex (MHC) genes, is assumed to be a very powerful and effective tool to keep pace with diverse and rapidly evolving pathogens. In my thesis, I studied natural levels of variation at the MHC genes, which have a key role in immune defence, and parasite burden in different small mammal species. I assessed the importance of MHC variation for parasite burden in small mammal populations in their natural environment. To understand the processes shaping different patterns of MHC variation I focused on evidence of selection through pathogens upon the host. Further, I addressed the issue of low MHC diversity in populations or species, which could potentially arise as a result from habitat fragmentation and isolation. Despite their key role in the mammalian evolution the marsupial MHC has been rarely investigated. Studies on primarily captive or laboratory bred individuals indicated very little or even no polymorphism at the marsupial MHC class II genes. However, natural levels of marsupial MHC diversity and selection are unknown to date as studies on wild populations are virtually absent. I investigated MHC II variation in two Neotropical marsupial species endemic to the threatened Brazilian Atlantic Forest (Gracilinanus microtarsus, Marmosops incanus) to test whether the predicted low marsupial MHC class II polymorphism proves to be true under natural conditions. For the first time in marsupials I confirmed characteristics of MHC selection that were so far only known from eutherian mammals, birds, and fish: Positive selection on specific codon sites, recombination, and trans-species polymorphism. Beyond that, the two marsupial species revealed considerable differences in their MHC class II diversity. Diversity was rather low in M. incanus but tenfold higher in G. microtarsus, disproving the predicted general low marsupial MHC class II variation. As pathogens are believed to be very powerful drivers of MHC diversity, I studied parasite burden in both host species to understand the reasons for the remarkable differences in MHC diversity. In both marsupial species specific MHC class II variants were associated to either high or low parasite load highlighting the importance of the marsupial MHC class II in pathogen defence. I developed two alternative scenarios with regard to MHC variation, parasite load, and parasite diversity. In the ‘evolutionary equilibrium’ scenario I assumed the species with low MHC diversity, M. incanus, to be under relaxed pathogenic selection and expected low parasite diversity. Alternatively, low MHC diversity could be the result of a recent loss of genetic variation by means of a genetic bottleneck event. Under this ‘unbalanced situation’ scenario, I assumed a high parasite burden in M. incanus due to a lack of resistance alleles. Parasitological results clearly reject the first scenario and point to the second scenario, as M. incanus is distinctly higher parasitised but parasite diversity is relatively equal compared to G. microtarsus. Hence, I suggest that the parasite load in M. incanus is rather the consequence than the cause for its low MHC diversity. MHC variation and its associations to parasite burden have been typically studied within single populations but MHC variation between populations was rarely taken into account. To gain scientific insight on this issue, I chose a common European rodent species. In the yellow necked mouse (Apodemus flavicollis), I investigated the effects of genetic diversity on parasite load not on the individual but on the population level. I included populations, which possess different levels of variation at the MHC as well as at neutrally evolving genetic markers (microsatellites). I was able to show that mouse populations with a high MHC allele diversity are better armed against high parasite burdens highlighting the significance of adaptive genetic diversity in the field of conservation genetics. An individual itself will not directly benefit from its population’s large MHC allele pool in terms of parasite resistance. But confronted with the multitude of pathogens present in the wild a population with a large MHC allele reservoir is more likely to possess individuals with resistance alleles. These results deepen our understanding of the complex causes and processes of evolutionary adaptations between hosts and pathogens. / In einer sich ständig verändernden Umwelt ist es unverzichtbar, sich fortwährend zu verändern und anzupassen. Dabei gründet sich das Anpassungsvermögen oder das evolutionäre Potential einer Art auf ihre genetische Variabilität. In der Krankheitsabwehr ist die Variabilität der Immungene ein besonders wichtiges und effektives Instrument, weil Pathogene sehr vielfältig sind und schnell evolvieren. Im Rahmen meiner Doktorarbeit habe ich mich mit der Variabilität des Immungen-Komplexes MHC (major histocompatibility complex) beschäftigt, der eine Schlüsselrolle in der Immunabwehr bei Vertebraten einnimmt. Anhand verschiedener Arten und Populationen von Kleinsäugern habe ich den Einfluss der MHC Vielfalt auf den Parasitenbefall unter natürlichen Bedingungen untersucht. Dabei interessierte mich insbesondere das Vorkommen geringer MHC Variabilität in Populationen, das möglicherweise eine Folge von Lebensraum-fragmentierung und Isolation ist. Obwohl Beuteltiere eine zentrale Rolle in der Evolution der Säugetiere spielen, ist über ihren MHC bislang nur sehr wenig bekannt. Einige Studien befassten sich mit Labor- oder Zootieren, und deuteten auf geringe oder sogar gar keine Variation im MHC Klasse II bei Beuteltieren hin. Allerdings gab es bislang nahezu keine Studien an frei lebenden Beuteltieren, deshalb war bislang ein natürliches Ausmaß der MHC Variabilität unbekannt. Anhand von zwei endemischen neotropischen Beuteltieren aus dem brasilianischen Küstenregenwald (Gracilinanus microtarsus, Marmosops incanus) habe ich überprüft, ob sich diese geringe MHC Vielfalt unter natürlichen Freilandbedingungen bestätigt. Erstmals konnte ich zeigen, dass der MHC II bei Beuteltieren charakteristische Merkmale positiver Selektion aufweist, die bisher nur von placentalen Säugern, Vögeln und Fischen bekannt waren: Positive Selektion auf spezifischen Aminosäurepositionen, Rekombination und Trans-Species-Polymorphismus. Darüber hinaus unterschieden sich die beiden Beuteltierarten beträchtlich in ihrer MHC II Variabilität. Während M. incanus sich als relativ wenig divers erwies, zeigte G. microtarsus eine zehnmal höhere Vielfalt und widerlegt damit die generelle Gültigkeit der ursprünglich angenommenen geringen MHC II Variabilität bei Beuteltieren. Um diese beachtlichen Diversitätsunterschiede zwischen den beiden Arten zu erklären, habe ich die Parasitenbelastung untersucht. Bei beiden Arten konnte ich nachweisen, dass bestimmte MHC Varianten mit entweder hoher oder niedriger Parasitenbelastung verknüpft waren. Solche Assoziationen spiegeln Pathogen-vermittelte Selektion wider, untermauern die Funktionalität des MHC Klasse II bei Beuteltieren und weisen auf dieselbe Bedeutsamkeit des MHC wie bei placentalen Säuger, Vögeln und Fischen hin. Ich entwickelte zwei alternative evolutionäre Szenarien, unter denen eine geringe MHC Variabilität denkbar ist. Im Szenario des ‘evolutionären Gleichgewichts’ ist geringe MHC Variabilität die Folge eines verminderten Selektionsdruckes durch wenige Parasiten, sodass eine geringe Parasitendiversität zu erwarten ist. Alternativ könnte eine geringe MHC Variabilität aber auch Folge eines kürzlich erlittenen Verlustes an genetischer Variabilität sein, beispielsweise durch ein Flaschenhalsereignis. Unter diesem Szenario des ‘Ungleichgewichts’ wäre bei M. incanus im Falle eines potentiellen Verlustes von Resistenzallelen eine starke Parasitenbelastung zu erwarten. Die parasitologischen Ergebnisse widersprechen dem ersten und deuten eher auf das zweite Szenario. M. incanus war deutlich stärker parasitiert als G. microtarsus, wohingegen die Parasitendiversität bei beiden Arten ungefähr gleich war. Die hohe Parasitenbelastung bei M. incanus ist offenbar weniger der Auslöser als vielmehr eine Folge seiner geringen MHC Vielfalt zu sein. Üblicherweise werden sowohl die Variabilität des MHC als auch seine Verknüpfung mit Parasitenbelastung innerhalb von einzelnen Populationen untersucht, nur selten wird die Variation zwischen Populationen in Betracht gezogen. Um Erkenntnisse auf dieser Ebene zu gewinnen, habe ich den Zusammenhang zwischen genetischer Vielfalt und Parasitenbelastung nicht auf der Ebene des Individuums, sondern auf der Populationsebene anhand der europäischen Gelbhalsmaus (Apodemus flavicollis) erforscht. Dabei wurden Populationen mit unterschiedlicher genetischer Variabilität am MHC und an neutralen genetischen Markern (Mikrosatelliten) betrachtet. Ich konnte nachweisen, dass Populationen, die über ein großes Spektrum verschiedener MHC Allele verfügen, besser gegen starke Parasitenbelastung gewappnet sind als Populationen mit einer geringen Anzahl MHC Allele. In einer MHC-diversen Population ist die Gegenwart von Individuen mit Resistenzallelen deutlich wahrscheinlicher, und damit die Überlebenswahrscheinlichkeit der Population. Diese Ergebnisse erweitern und vertiefen unsere Erkenntnisse zu die komplexen evolutionären Vorgängen und Mechanismen zwischen Wirt und Parasit in ihrem fortwährenden Wettstreit.

Abstract Fishpond area of Sihcao, Tainan City, approximate 488 hectors, is a part of coastal wetlands of Taiwan. Fishponds can be found almost everywhere in the wetlands, readily forming a fragmented ecosystem. Previous studies on populations of small mammals in coastal wetlands of Taiwan are scarce. Disturbance types found in the study area include straying dogs, working farmers, tillaging of the fishponds, and typhoons, etc, which would probably reduce the abundance of small mammals. The resources such as shelter, vegetation coverage, insects and seeds would increase the abundance of small mammals. The seasonal changes of these environmental factors may in turn affect the population dynamics of small mammals. I monitored the monthly population fluctuation of small mammals and invertebrates in the fishpond habitats, 2008. Six species of small mammals and 106 species of invertebrates were found. The small mammal populations in the Hairy Beggar Ticks region were compared with those within the non-Hairy Beggar Ticks region. More small mammals were found in the Hairy Beggar Ticks region in the sampling period. The vegetation coverage of the former was higher than that of the latter. There was positive correlation between evenness of small mammals and temperature. No differences of the biodiversity of invertebrates were found between the regions in the year. Significant correlation existed between the sunshine duration and the richness of invertebrates. The correlation may be due to the change of photoperiod. There was no significant correlation between the richness of small mammals and that of invertebrates.

Studies of secondary seed dispersal by small mammals have largely been focused on the interaction between nut-bearing tree species and sciurid rodents such as squirrels, and on heteromyid rodents in the southwestern United States. However, there is now evidence that wind-dispersed tree species such as pines also undergo a process of secondary seed dispersal, where animals redistribute (cache) seeds that have already fallen to the ground, often in microhabitats more suitable for successful seed germination. In Florida sandhill, where fire suppression has threatened wind-dispersed longleaf pine ( Pinus palustris) by encouraging the encroachment of hardwoods such as sand live oak ( Quercus geminata), secondary seed dispersal may be an important factor in determining community composition and persistence of longleaf pine systems. Using a combination of seed depots and seed predator exclosures, I looked at both longleaf pine and sand live oak in terms of whether small animals such as squirrels ( Sciurus carolinensis) and cotton mice ( Peromyscus gossypinus) cache the seeds, and where the seeds of these two tree species best germinate. Since sand live oak acorns are prone to infestation by weevils ( Curculio spp.), I also examined whether nut condition affects acorn germination potential. I found that longleaf pine seeds are cached by small mammals to a small degree. While these seeds are not moved great distances from where they originate, they are often redistributed into microhabitats that promote successful seed germination. Caging experiments indicated that seeds were most likely to germinate when buried in open areas between adult trees, and to some degree, under shrub cover. On the other hand, sand live oak acorns appear to face heavy predation by large seed predators such as raccoons ( Procyon lotor) and wild pigs (Sus scrofa). Those acorns that do escape predation, including weevil-infested acorns, may provide an opportunity for seedling establishment. However, it appears that sand live oak depends heavily on vegetative sprouting for regeneration. This suggests that even in the absence of fire, longleaf pines in Florida sandhill are able to persist through secondary seed dispersal by small animals coupled with heavy seed predation on competing sand live oak.

Habitat fragmentation and destruction caused by linear infrastructure, including roads, railways, and power line corridors, are recognized as major threats to biodiversity around the world. Roads can act as barriers by impeding animal movement and restricting animal space use. An understanding of factors that influence barrier effects is important to discern the impacts of habitat fragmentation and to develop appropriate mitigation. The barrier effects of roads are driven by several distinct but not mutually exclusive mechanisms that include traffic, edge, and gap avoidance. We used an endangered forest obligate, the Mount Graham red squirrel (Tamiasciurus hudsonicus grahamensis), as our study organism to assess effects of traffic noise on animal occurrence and demonstrated that traffic noise had spatially extensive and negative effects on site occupancy after accounting for effects of distance from roads and the environment. We investigated barrier effects of forest roads and assessed effects of traffic, road edges, and canopy gaps on space use of Mt. Graham red squirrels and compared to the response of introduced, edge-tolerant Abert's squirrels (Sciurus aberti). Forest roads acted as partial barriers for red squirrels regardless of traffic volume likely due to avoidance of canopy gap created by roads, whereas Abert's squirrels showed no avoidance of roads. Therefore, roads restricted movement and space use of a native forest-dependent species while creating habitat preferred by an introduced, edge-tolerated species. Through a meta-analysis of studies that quantified road crossing behavior by mammals, we found that all types of roads, from major highways to narrow forest roads, can impede movement for certain species of mammals. Magnitude of barrier effects of roads decreased as species body mass increased, and was affected positively by increasing road width. We suggest that the species-specific magnitude of barrier effects of roads may be anticipated with basic information from life history traits and road characteristics that are readily accessed through open resources or easily measured.

SMULKIŲJŲ ŽINDUOLIŲ RŪŠINĖ SUDĖTIS IR MIGRACIJA NEMUNO DELTOS REGIONINIO PARKO UŽLIEJAMOSE PIEVOSE Agnė Janonytė Nemuno deltos regioninis parkas – vienintelis gamtinis kompleksas Lietuvoje ir visame Baltijos jūros regione, pasižymintis didele biotopų įvairove gana nedidelėje teritorijoje. Europinės svarbos buveinės – tai šiame parke esančios užliejamos pievos, turinčios unikalių biotos ir kraštovaizdžio elementų. Per Nemuno deltą eina Arktikos-Europos-Rytų Afrikos paukščių migracijos kelias, todėl didelė paukščių įvairovė patraukia ornitologų dėmesį, o smulkieji žinduoliai šiame regione mažai ištirti. Tyrimai buvo vykdomi nuo 2004 m. iki 2006 m. Rusnės saloje ir Žalgirių miške. Iš viso sugautas 621 individas, priklausantis 10 rūšių. Absoliutus dominantas buvo pelkinis pelėnas (M. oeconomus) kuris sudarė 55% visų individų. 2006 m. pelkinių pelėnų (M. oeconomus) bendras vados dydis buvo didesnis neužliejamose pievose – 6.20±0.38 (3–10) embrionai, palyginus su užliejamomis – 5.87±1.10 (2–11) embrionai. Jis priklausė nuo sezono. Pavasarį (gegužės mėn.) buvo didesnis užliejamose pievose, nei neužliejamose, atitinkamai: 10.0±1.0 ir 7.75±0.63 embrionai. Kiekvienais metais dalis Rusnės salos pievų užliejamos, o vandeniui atslūgus rekolonizuojamos. Rekolonizacija – laipsniškas procesas. Be to, smulkieji žinduoliai pasižymi skirtingomis šlapios pievos rekolonizacijos strategijomis. Pirmieji į šlapią pievą migruoja pelkiniai pelėnai (M. oeconomus) – tipiški drėgnų pievų gyventojai... [toliau žr. visą tekstą] / THE SPECIFIC STRUCTURE AND MIGRATION OF SMALL MAMMALS IN THE FLOODED MEADOWS OF THE NEMUNAS DELTA Agnė Janonytė The Nemunas Delta Regional Park (W. Lithuania) is characterized by exceptional habitat diversity. Flooded meadows on Rusnė Island border with non-flooded meadows and are separated by channels and dikes. Birds are well known in the area, as the site is enlisted as a habitat of the European importance and Ramsar site, but small mammals were scarcely investigated to date. Small mammals were trapped from June 2004 to October 2006. The total catch in both flooded and non-flooded meadows was 621 specimens. They belong to 10 species. The absolute dominant was root vole (M. oeconomus), with the share of 55% in the whole area. For the first time in Lithuania, the data on breeding of M. oeconomus were collected (32 cases). We found litter size differences according to the season and habitat. Totally, litter size of M. oeconomus in flooded meadows was 5.87±1.10 (2–11), while that in non-flooded meadows – 6.20±0.38 (3–10) embryo. In May, litter size was higher in flooded meadows – 10.0±1.0 vs. 7.75±0.63 embryo. Each year a part of the meadows is flooded and re-colonized. Migration is an inevitable process in small mammal ecology. Recolonization was found to be a progressive process, resulting in heterogeneous distribution of small mammals in the floodplain. From summer to autumn densities increased and specimens could be observed on larger distances from the non-flooded areas... [to full text]