<p>Genetic variation within and among populations is a result of past and ongoing processes. Among the most important of such processes are dispersal, habitat fragmentation and selection. This thesis use neutral genetic variation as a tool to investigate these processes in three bird species.</p><p>In the Siberian jay, the timing of dispersal is dependent on social dominance among siblings. Mark-recapture data, radio-tracking and genetic variation was used to investigate whether timing of dispersal had an effect on dispersal distance. The results show that early dispersing individuals also disperse longer. In the same species, genetic correlation between neighbours was used to find areas with high production of philopatric individuals, which could be indicative of high habitat quality.</p><p>Great snipe populations in northern Europe have a breeding range divided into two regions. A Q_ST-F_STapproach was applied to study variation in selection between regions. Differentiation between the regions in neutral molecular markers was low, indicating high gene flow, or short time available for neutral divergence. Morphological divergence between the regions was high, and Q_ST > F_ST, which indicates divergent selection. Thus, neutral genetic markers can be misleading in identifying evolutionary significant units, and the Q_ST-F_ST approach might be valuable to identify targets for conservation.</p><p>Rock ptarmigan, or its ancestors, originated in Beringia, and spread throughout the Holarctic region. Their distribution has subsequently been affected by glaciations, most likely leading to withdrawals and re-colonisations. Neutral genetic variation among five populations around the northern Atlantic was investigated. There was strong genetic structure among the populations, and evidence that Scandinavian rock ptarmigan has been isolated from other populations for considerable time. Rock ptarmigan in Svalbard showed slightly lower genetic variation than others, and comparisons with other studies suggested an eastern colonisation route to Svalbard.</p>

Studies of the maternally inherited mitochondrial DNA in loggerhead sea turtles (Caretta caretta) demonstrate that females are philopatric, returning to nest in the region where they hatched. Eleven genetic stocks of maternal lineages have been identified in the Atlantic Ocean. An analysis of the conventionally-used 380 bp of the mitochondrial control region of a sample of individuals from the genetic stock of loggerheads in Mexico (N = 175) revealed 13 haplotypes. When a longer sequence read of 815 bp was analyzed, 17 haplotypes were uncovered. In the genetic stock of loggerheads in northwestern Florida (N = 25), three haplotypes were identified with both control region sequence lengths. Based on the currently known distributions of the three long CC-A1 and CC-A2 haplotypes, two of each are unique to Mexico. This makes the longer sequence reads useful for stock identification. Within Mexico, there was evidence of significant population structuring between Cozumel and the northern region of the sampling area on mainland Mexico (pairwise ϕST = 0.1003, p = 0.0197), but not after Bonferroni correction. A direct comparison of female and male nuclear microsatellite genotypes indicated male-biased dispersal between Mexico and northwestern Florida. Within Mexico, microsatellite analysis indicated significant structuring of females between sampling years and between the northern and the southern region of the sampling area on the mainland. Consequently, this genetic stock, while perhaps not in equilibrium, shows signs of female natal homing. An analysis of clutches indicated that significantly more clutches in Mexico had multiple paternity compared to the northwestern Florida (66% and 23%, respectively). The frequency of multiple paternity was not correlated with female abundance, nest density or sex ratio of reproductively successful individuals. There was no evidence of females benefiting through increased reproductive success from multiple paternity. This is consistent with other studies of sea turtles.

Genetic variation within and among populations is a result of past and ongoing processes. Among the most important of such processes are dispersal, habitat fragmentation and selection. This thesis use neutral genetic variation as a tool to investigate these processes in three bird species. In the Siberian jay, the timing of dispersal is dependent on social dominance among siblings. Mark-recapture data, radio-tracking and genetic variation was used to investigate whether timing of dispersal had an effect on dispersal distance. The results show that early dispersing individuals also disperse longer. In the same species, genetic correlation between neighbours was used to find areas with high production of philopatric individuals, which could be indicative of high habitat quality. Great snipe populations in northern Europe have a breeding range divided into two regions. A QST-FST approach was applied to study variation in selection between regions. Differentiation between the regions in neutral molecular markers was low, indicating high gene flow, or short time available for neutral divergence. Morphological divergence between the regions was high, and QST &gt; FST, which indicates divergent selection. Thus, neutral genetic markers can be misleading in identifying evolutionary significant units, and the QST-FST approach might be valuable to identify targets for conservation. Rock ptarmigan, or its ancestors, originated in Beringia, and spread throughout the Holarctic region. Their distribution has subsequently been affected by glaciations, most likely leading to withdrawals and re-colonisations. Neutral genetic variation among five populations around the northern Atlantic was investigated. There was strong genetic structure among the populations, and evidence that Scandinavian rock ptarmigan has been isolated from other populations for considerable time. Rock ptarmigan in Svalbard showed slightly lower genetic variation than others, and comparisons with other studies suggested an eastern colonisation route to Svalbard.

Die Beziehung zwischen Genen und Verhalten ist in der Evolutionsbiologie von besonderem Interesse. Bestimmte Verhaltensweisen können die genetische Struktur natürlicher Populationen gestalten, dadurch deren genetische Diversität verändern und so ihr evolutives Schicksal beeinflussen. Abwanderung aus der Geburtsgruppe ist eine dieser Verhaltensweisen. Sie beeinflusst Genfluss, dessen Ausmaß die genetische Struktur von Populationen bestimmt. Paviane (Gattung Papio) sind ein besonders interessantes Forschungssystem um die Beziehung zwischen Verhalten und populationsgenetischer Struktur zu untersuchen. Die Evolution der Paviane wurde sowohl von historischem als auch gegenwärtigem Genfluss geprägt. Innerhalb dieser Gattung treten sowohl die überwiegende Abwanderung von Männchen als auch die überwiegende Abwanderung von Weibchen auf. Zudem wurde ihre gegenwärtige Verbreitung maßgeblich von Populationsausbreitung und –rückzug beeinflusst und es tritt häufig Genfluss zwischen verschiedenen Arten auf. In meiner Doktorarbeit untersuchte ich, wie verschiedene Abwanderungsmuster den Genfluss bei Pavianen beeinflussen. Damit hoffe ich zu einem besseren Ver-ständnis der Wechselbeziehung zwischen Verhaltensökologie und Genetik in natürlichen Populationen beizutragen. Ich fokussierte mich darauf, wie Unterschiede in den Sozialsystemen unterschiedlicher Pavianarten deren genetische Struktur beeinflussen. Die beobachteten Muster nutzte ich, um auf das geschlechtsspezifische Abwanderungsmuster bei Guineapavianen zu schließen, eine der am wenigsten untersuchten Pavianarten. Zudem untersuchte ich, wie sowohl historischer als auch gegenwärtiger Genfluss die genetische Struktur der Guineapaviane formten und ob es möglich ist von der Populationsausbreitung der Paviane Rückschlüsse auf die menschliche Evolutionsgeschichte zu ziehen. Um diese Fragen zu beantworten nutzte ich einen populationsgenetischen Ansatz, basierend auf im gesamten Verbreitungsgebiet gesammelten Kotproben, deren exakter geographischer Ursprung bekannt war. Ich analysierte sowohl autosomale Mikrosatelliten als auch Sequenzen der mitochondrialen Hypervariablen Region I. Meine Ergebnisse zeigen, dass die genetische Struktur der Guineapaviane am besten durch die überwiegende Abwanderung von Weibchen erklärt werden kann, sowohl in einem lokalen als auch im globalen Kontext. Weiblicher Genfluss führt zu einer hohen Diversität innerhalb von Populationen sowie einem Fehlen von genetisch-geographischer Struktur in mitochondrialer DNA. Nukleäre DNA hingegen zeigt eine starke globale geographische Struktur und Männchen sind im Vergleich zu Weibchen durch eine stärkere lokale Struktur gekennzeichnet. Dies entspricht den Vorhersagen für ein System, in welchem hauptsächlich Weibchen abwandern und Männchen in ihrer Geburtsgruppe verbleiben. Insgesamt scheint lokal begrenzte Abwanderung den wirksamen Genfluss auf eine Distanz unter 200 km zu beschränken, was zu einem starken Isolation-durch-Distanz Effekt und genetisch differenzierten Populationen führt. Anzeichen für Populationsausbreitung, die graduelle Struktur genetischer Variation, und mögliche Hinweise auf das “Allele-surfing” Phänomen, deuten auf eine historische westwärts gerichtete Ausbreitung von Guineapavianen hin. Introgressive Hybridisierung mit benachbarten Anubispavianen könnte genetische Muster im Bereich der Kontaktzone erklären, muss aber im Detail noch untersucht werden. Zusätzlich konnte ich zeigen, dass Mantelpaviane vermutlich im gleichen Zeitraum des Späten Pleistozäns von Afrika nach Arabien wanderten, wie Hypothesen für den modernen Menschen vorschlagen. Meine Studie ist die erste umfassende Analyse der genetischen Populationsstruktur der Guineapaviane und liefert Belege für die überwiegende Abwanderung von Weibchen in dieser Art. Dies untersützt die Ansicht, dass das Sozialsystem der Guineapaviane einige vergleichbare Merkmale zum System der Mantelpaviane aufweist und deutet somit darauf hin, dass während der Evolution dieser beiden Arten besondere evolutionäre Drücke gewirkt haben, die sie von allen anderen Pavianarten abgrenzen. In Kombination mit dem starken Einfluss von Populationsausbreitungen auf ihre Verbreitung und genetische Diversität, bekräftigt meine Arbeit Paviane als interssanten analogen Modellorganismus, der helfen kann, die Prozesse die während der Evolution des Menschen maßgeblich waren, aufzuklären.

The goal of this study was to examine several aspects of the population genetics and population biology of the Nigeria-Cameroon chimpanzee at seven sampling locations in the south of Taraba State, Nigeria. Three of the sampling locations are within GGNP and two are situated just outside the southern boundary of GGNP. The final two sampling locations are found within Ngel Nyaki forest reserve, at each of the two forest fragments inside the reserve. Ngel Nyaki forest reserve was the focus of the study and the principal goal was to 16 determine if the community of chimpanzees at Ngel Nyaki forest reserve has become isolated from the chimpanzees at GGNP using microsatellite loci extracted from non-invasive sources of DNA. In Chapter two, the methods used to extract and amplify the DNA and the protocols used to confirm the genotypes are outlined. Chapter three examines the population structure of the chimpanzees among the regions sampled in this study, particularly addressing the question as to whether the chimpanzees at Ngel Nyaki forest reserve are isolated from the chimpanzees at GGNP. Chapter four investigates patterns of sex biased dispersal in the Nigeria-Cameroon chimpanzee. In Chapter five, population viability analysis is used to determine the fate of the chimpanzees at Ngel Nyaki forest reserve under a range of management scenarios. Chapter six summarizes the conclusions of the study and presents a conservation strategy to ensure the viability of the population of chimpanzees at Ngel Nyaki forest reserve.

No description available.

Habitat fragmentation can have an impact on a wide variety of biological processes including abundance, life history strategies, mating system, inbreeding and genetic diversity levels of individual species. Although fragmented populations have received much attention, ecological and genetic responses of species to fragmentation have still not been fully resolved. The current study investigated the ecological factors that may influence the demographic and genetic structure of the giant white-tailed rat (Uromys caudimaculatus) within fragmented tropical rainforests. It is the first study to examine relationships between food resources, vegetation attributes and Uromys demography in a quantitative manner. Giant white-tailed rat densities were strongly correlated with specific suites of food resources rather than forest structure or other factors linked to fragmentation (i.e. fragment size). Several demographic parameters including the density of resident adults and juvenile recruitment showed similar patterns. Although data were limited, high quality food resources appear to initiate breeding in female Uromys. Where data were sufficient, influx of juveniles was significantly related to the density of high quality food resources that had fallen in the previous three months. Thus, availability of high quality food resources appear to be more important than either vegetation structure or fragment size in influencing giant white-tailed rat demography. These results support the suggestion that a species’ response to fragmentation can be related to their specific habitat requirements and can vary in response to local ecological conditions. In contrast to demographic data, genetic data revealed a significant negative effect of habitat fragmentation on genetic diversity and effective population size in U. caudimaculatus. All three fragments showed lower levels of allelic richness, number of private alleles and expected heterozygosity compared with the unfragmented continuous rainforest site. Populations at all sites were significantly differentiated, suggesting restricted among population gene flow. The combined effects of reduced genetic diversity, lower effective population size and restricted gene flow suggest that long-term viability of small fragmented populations may be at risk, unless effective management is employed in the future. A diverse range of genetic reproductive behaviours and sex-biased dispersal patterns were evident within U. caudimaculatus populations. Genetic paternity analyses revealed that the major mating system in U. caudimaculatus appeared to be polygyny at sites P1, P3 and C1. Evidence of genetic monogamy, however, was also found in the three fragmented sites, and was the dominant mating system in the remaining low density, small fragment (P2). High variability in reproductive skew and reproductive success was also found but was less pronounced when only resident Uromys were considered. Male body condition predicted which males sired offspring, however, neither body condition nor heterozygosity levels were accurate predictors of the number of offspring assigned to individual males or females. Genetic spatial autocorrelation analyses provided evidence for increased philopatry among females at site P1, but increased philopatry among males at site P3. This suggests that male-biased dispersal occurs at site P1 and female-biased dispersal at site P3, implying that in addition to mating systems, Uromys may also be able to adjust their dispersal behaviour to suit local ecological conditions. This study highlights the importance of examining the mechanisms that underlie population-level responses to habitat fragmentation using a combined ecological and genetic approach. The ecological data suggested that habitat quality (i.e. high quality food resources) rather than habitat quantity (i.e. fragment size) was relatively more important in influencing giant white-tailed rat demographics, at least for the populations studied here . Conversely, genetic data showed strong evidence that Uromys populations were affected adversely by habitat fragmentation and that management of isolated populations may be required for long-term viability of populations within isolated rainforest fragments.

Black grouse (Tetrao tetrix) is a bird species with a lek mating system found in the Palearctic boreal taiga. It is assumed that it has a continuous distribution along Scandinavia and Siberia, whereas in Central Europe it has declined during the last decades. The primary objective of this thesis was to obtain a deeper understanding of the history, systematic classification and the genetic structure of black grouse on different geographical scales using microsatellites and control region mtDNA sequences (CR). I determined how much the mating system, habitat fragmentation and historical population processes have influenced the partitioning of genetic diversity in this species. Phylogeographical results are consistent with a demographic population expansion, and the patterns of postglacial dispersal suggest that a glacial refugium was located somewhere in central Asia, and from there black grouse spread out to Europe following the retreat of glacial ice sheets. I suggest that the two European black grouse subspecies, T. t. Tetrix and T. t. britannicus correspond to only one subspecies: T. t. tetrix, and that this lineage has diverged from T.t. viridanus, a subspecies found in Kazakhstan. The British population is significantly divergent from the remaining Eurasian samples for microsatellites but it is not for mtDNA. Therefore, they should regard as a separate Management Unit and not as a subspecies. Furthermore, British black grouse occur in three independent genetic units, corresponding to Wales, northern England/southern Scotland and northern Scotland. There was also genetic structure within Sweden. Habitat fragmentation is the main cause of population genetic structure in southern Swedish black grouse. In contrast, low levels of genetic differentiation and high connectivity were found in northern Sweden due to female-biased dispersal. On a finer geographical scale, I found genetic differences between leks due to a mixture of related and unrelated individuals within leks. However, mean relatedness values hardly differed from zero. Some leks were similar to one another and I interpret this as a result of variation in local reproductive success and philopatry. These factors would cause genetic structuring but this by itself would not reveal that kin selection is operating within black grouse leks.