| 1. |
- Ahlgren, Hans, 1984-
(författare)
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Prehistoric human impact on wild mammalian populations in Scandinavia
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis aims to study the interactions of pre-agricultural societies in Scandinavia with wild mammals, for example in terms of hunting and translocation. More specifically, the aim is to investigate the possibility of identifying examples of overexploitation, targeted hunting or translocation of wild mammals in prehistoric Scandinavia, and to discuss the implications this could have had for both the wild animals and the humans. The thesis also studies translocation to evaluate the feasibility of using it as a proxy for prehistoric human mobility, and to understand the motivation for this action. Although the focus is on the animals in this thesis, the ultimate purpose is to study humans and their interactions with animals in prehistory. The thesis applies genetic analyses to zooarchaeological material of various mammalian species from different Scandinavian sites, in order to study whether the genetic structures have changed in these species over time, and to assess whether these changes were induced by different human actions. The species studied in this thesis were selected on the basis of the importance they are considered to have had for prehistoric people.The dissertation comprises five studies. The first study investigates the occurrence of mountain hares on the island of Gotland, and discusses how they got there and where they came from. The second study explores the temporal genetic structure of the grey seal in the Baltic Sea, and discusses whether humans and/or climate were the drivers for the sudden disappearance of grey seals from the island of Stora Karlsö. The third study concerns a shift where moose apparently became less important as prey in northern Sweden at the end of the Neolithic period, and discusses whether humans targeted female moose in hunting. The fourth study analyses and discusses the history of the harp seal in the Baltic Sea. The fifth study is a methodological paper which involves identifying seals according to sex, using the dog genome.The overall result of the different case studies shows that there were major population fluctuations over time in all the species studied, and that in some cases, humans are likely to have contributed to this, e.g. through overhunting and translocation. The study also shows that the population fluctuations often occurred in connection with certain climatic events, though it was not possible to separate climatic effects from human impact in terms of the cause.
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| 2. |
- Kempe Lagerholm, Vendela, 1983-
(författare)
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Animal movement on short and long time scales and the effect on genetic diversity in cold-adapted species
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The genetic diversity in modern species is strongly affected by contemporary gene flow between populations, which in turn is governed by individual dispersal capacities and barriers in the landscape. However, current patterns of variation have also been shaped by movement over longer time-scales, such as the successive shifts in species distributions that have occurred during past climate changes. This thesis is focused on cold-adapted species, and one parameter that has greatly influenced their current genetic diversity is how they coped with climate warming at the last glacial/interglacial transition, ca 11.7 thousand years ago. I examined this in three different small herbivore taxa; true lemmings (Lemmus), ptarmigan (Lagopus) and hares (Lepus), whose modern distributions stretch from the exposed tundra to the subarctic moorlands and taiga. In the first paper, I investigated contemporary genetic structure in the cyclic Norwegian lemming (Lemmus lemmus) and proposed that mass movements during peak years act as pulses of gene flow between mountain areas, which homogenise the gene pool over surprisingly vast geographic distances. However, when I used ancient DNA to analyse the lemmings’ ability for long-term directional movement, I found that the Ice Age populations that inhabited the former midlatitude European tundra-steppe appear to have been incapable of shifting their distribution northwards following post-glacial climate warming. Instead, the results suggest that the endemic Norwegian lemming descends from an isolated population that survived the last glacial maximum in situ in a restricted ice free refugium. In contrast to the glacial lemmings, as well the majority of previously studied mammals, the ptarmigan (L. lagopus and L. muta) and hare (L. timidus) analyses revealed a long-term genetic continuity in Europe, where the midlatitude populations were able to keep pace with the rapidly changing climate at the last glacial/interglacial transition, enabling them to shift their ranges to northern and high-alpine regions. These different outcomes might be explained by ptarmigans’ flight capability that allows a less restricted dispersal across fragmented landscapes, and that the generalist nature of mountain hares makes them less vulnerable to habitat alterations. Species distribution modelling, however, indicated that continued climate warming will make some isolated regions unsuitable in the future, thereby forcing populations to adapt the new environmental conditions in order to avoid local extinctions.
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| 3. |
- Lindgren, Åsa, 1973-
(författare)
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Effects of herbivory on arctic and alpine vegetation
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The distribution of plant species and functional traits in alpine and arctic environments are determined by abiotic conditions, but also by biotic interactions. In this thesis, I investigate interactions among plants and herbivory effects on plant community composition and plant functional traits in three different regions: Swedish Lapland, Beringia (USA/Russia) and Finnmark (Norway). Reindeer grazing was found to be extensive in southern Lapland and had limited effects on plant community composition and seedling germination. However, reindeer presence was found to influence plant functional traits, particularly in the subalpine birch forest. Tall herbs were lower and had lower SLA when reindeer were present, while small herbs showed an opposite pattern. The contrasting effects on the two herb groups are probably explained by a competitive release for small herbs when the tall herbs are suppressed by reindeer. Rodents had the largest relative impact on plant community composition in southern Lapland and this is consistent with the study from Finnmark, where rodents heavily affected dwarf shrubs on predator-free islands. With no predators present, vole densities increased profoundly and almost depleted some dwarf shrub species. These results support the idea that small mammals in arctic and alpine tundra are controlled by predators (i.e. top-down). However, a decrease in the nutritional quality in a sedge after defoliation gives support for the idea that small mammals are regulated by plant quality (i.e. bottom-up). In Beringia, small and large herbivores differed in the relation to plant community composition, since large herbivores were related to species richness and small herbivores were related to plant abundance. Plant functional traits were related only to large herbivores and standing crop of vascular plants.
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| 4. |
- Norén, Karin, 1980-
(författare)
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Genetic structure in the North- population connectivity and social organization in the Arctic fox
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Genetic variation is distributed on different spatial and temporal scales, reflecting the ecological and geographical complexity in the habitat. In this thesis, the primary objective was to obtain a comprehensive understanding of the genetic structuring in the Arctic fox (Vulpes lagopus) and to identify the underlying factors forming these structures. Using microsatellites, presence of sea ice was identified as the main factor determining the large-scale genetic structure in the Arctic fox. Genetic distinctiveness was demonstrated for populations surrounded by year-round open water (i.e. Iceland and Scandinavia) and among areas connected by sea ice, genetic differentiation was mainly determined by the geographic distance (PAPER I). Movement across the sea ice was influenced by fluctuations in resource abundance caused by the lemming cycle. As a consequence of low lemming abundance, long-distance movement from inland habitats into coastal habitats influenced the genetic structure on a temporal scale (PAPER II). Although the global connectivity was determined by few underlying factors, local population structures were influenced by population-specific historical, demographic and ecological factors (PAPER II, III, IV). Geographical barriers determined genetic structure within the isolated population on Iceland (PAPER III), whereas immigration influenced the local genetic structure in both Svalbard (PAPER II) and Scandinavia (PAPER IV). When population size is low, few immigration events cause rapid changes in genetic composition (PAPER IV), while immigration had a less pronounced effect in larger populations (PAPER II). On the social scale, high flexibility regarding the composition of social groups was recorded as a likely response to local habitat conditions (PAPER V). Complex social groups were more common in habitats with high resource availability and presence of predators than in habitats without predation. This thesis illustrates the importance of ecology and demography forming genetic structure at different scales, and highlights the Arctic fox vulnerability to the ongoing climate change.
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| 5. |
- Erlandsson, Rasmus, 1985-
(författare)
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Spatial and temporal population dynamics in the mountain tundra – mesopredator and prey
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- It is well known that competition, predation and fluctuating food resources can have strong effect on individual fitness and population dynamics. The complexity of natural systems can make it complicate to disentangle those processes, but environments with relatively simple food webs, and strong cyclic population dynamics offer contrasting conditions resembling experimental treatments. This thesis concerns the spatial and temporal implications of fluctuations in small rodent abundance on two trophic levels in a highly cyclic ecosystem, the Scandinavian mountain tundra. The first two chapters focus on plant biomass and spatiotemporal distribution in the Norwegian lemming (Lemmus lemmus), while the three last papers focus on the direct and indirect effects of small rodent fluctuations and territory quality on reproductive success, juvenile survival and group living in a lemming specialist mesopredator, the arctic fox (Vulpes lagopus). By developing, validating and applying a novel application of aerial photos for remote sensing of plant biomass (Chapter I), we found that food availability predicted lemming distribution during population peaks, but that they were more habitat specific during increase years when intraspecific competition was lower (Chapter II). Arctic fox reproduction is tightly connected to small rodent abundance but the effects of geographical variation in food availability is less well known. We used 17 years of population surveys of an arctic fox subpopulation in mid Sweden (Helagsfjällen) to investigate potential effects. During small rodent increase years, we found that arctic fox litter sizes were smaller in territories of intermediate plant productivity, compared to both more and less productive territories (Chapter III). This could be an effect of limited food availability together with increased presence of red foxes (Vulpes vulpes), a stronger and potentially lethal competitor. However, when small rodents peaked, and competition would be expected to decrease, we saw no effect of territory productivity. Based on a smaller data set concerning juvenile summer survival, we found that the mortality rate among juveniles born by first time breeding arctic fox females were more sensitive to low small rodent prey abundance (Chapter IV). We explain it with an increased predation pressure from top-predators that switch from small rodents to alternative prey when small rodents decline, as suggested by an observed positive effect on juvenile survival by adult presence on den sites. Arctic foxes are socially flexible, and several adults can share a den with the resident pair, potentially increasing juvenile survival and help in territorial defence. Returning to the 17-year data set, we tested the Resource Dispersion Hypothesis predicting that increased resource availability should increase group size (Chapter V). We found support for this prediction as group living increased during the small rodent peak phase. However, it remained unexpectedly high during the decrease phase, when resources are scarce. This could however be related to increased predation pressure, and an increasing benefit of group living.
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| 6. |
- Hellström, Peter, 1978-
(författare)
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Predator responses to non-stationary rodent cycles
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Regular fluctuations in population size, cycles, are common in small mammals and have important effects on predator populations and life histories. In this thesis, I identify long-term patterns and processes in two specialist predators, the arctic fox Vulpes lagopus and the rough-legged buzzard Buteo lagopus, in relation to their prey (lemmings and voles) and in the case of the arctic fox also to a dominant competitor, the red fox Vulpes vulpes. The results demonstrate that the specialist predators as expected were limited by food supply, which was revealed by combining long-term monitoring with a pseudo-experimental approach. But dampening of cycles has led to long-term declines in the predator populations. Cycles in red and arctic foxes disappeared in the 1970s and 1980s. A return to cyclic dynamics was found locally in the red fox in the boreal zone, but monitoring in the mountain region identified a widespread return of cycles in both lemmings and voles in the early 2000s. This increase in natural food was sufficient to halt the decline in the arctic fox population, but a large-scale field experiment revealed that only supplementary fed subpopulations increased in size. Competition with the red fox further had a negative impact on the arctic fox population. A theoretical model suggested that this asymmetric competition is context dependent and most severe if red fox numbers are independent of rodent density due to access to alternative food. The number of breeding rough-legged buzzards was determined primarily by rodent abundance, but has been nearly halved since the 1970s and was decoupled from rodents in the most recent years. Reproductive output is currently also lower due to smaller clutch sizes. The functional responses of the rough-legged buzzard were complex and differed between lemmings and voles. Rodent cycles are clearly essential for maintaining biodiversity, but spatiotemporal patterns and effects on ecological communities are increasingly variable.
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| 7. |
- Larm, Malin, 1990-
(författare)
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Relationship between wildlife and tourism - interdisciplinary insights from Arctic fox tourism in Sweden
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Interactions between wildlife and tourism can be studied from several different perspectives and the effects of such interactions can influence animals both positively and negatively with effects on both individual and population levels. This thesis takes an interdisciplinary approach, combining both natural and social perspectives, when studying the effects of tourism activity on a small population of the endangered arctic fox (Vulpes lagopus). We have studied arctic foxes inhabiting disturbed and undisturbed den sites in Helagsfjällen, which is the southernmost population of arctic foxes in Sweden and a popular area for recreational activities such as hiking, skiing and camping. The overall objective of the thesis has been to contribute to good management of both arctic foxes and tourism within the study area, as well as to contribute with a comprehensive study of simultaneous disturbance effects and fitness consequences of wildlife tourism activities to the scientific field of wildlife-tourism interactions. The first two papers focus on different aspects of behavioral responses of arctic foxes towards human activity, the third paper evaluates potential fitness consequences and the fourth paper focus on the tourist aspect of the interaction. Behavioral changes in response to tourism disturbance that have been identified in the foxes include changes in vigilance and probability of hiding (Paper I), temporal activity shift at the den site (Paper II) and increased tolerance to human activity (Paper I, Paper II). Juvenile summer survival was higher at disturbed dens compared with undisturbed dens during years of declining small rodent densities (Paper III). Small rodent decline years is when the predation on arctic foxes is presumed to be highest and we suggest that the positive fitness effect could be mediated by a human-induced predator refuge for the foxes in close proximity of human activity. On the tourist aspect, we have identified effects on behavior, knowledge and awareness of the situation for arctic foxes and related conservation work (Paper IV). Overall, results in this thesis showed a high level of context-dependency, which highlights the importance of considering factors such as food availability, intra-species interactions and individual traits such as previous experience with humans. Consequently, the work in this thesis together with ongoing studies of hormonal stress responses constitutes one of the more comprehensive scientific studies of tourism effects on terrestrial mammals. The output from this thesis brings important deliverables for species-specific management and conservation, but also for other species given the rapidly growing interest for wildlife tourism.
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| 8. |
- Meijer, Tomas, 1980-
(författare)
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To survive and reproduce in a cyclic environment – demography and conservation of the Arctic fox in Scandinavia
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis concerns the conservation and life history of the Arctic fox (Vulpes lagopus) in Scandinavia. The Arctic fox was historically a widely distributed species in the Scandinavian mountain tundra with a population size of approximately 10 000 individuals during years with high resource availability, i.e. rodent peaks. However, due to over-harvest in the end of the 19th century, the population numbers declined to a few hundred individuals. Although legally protected for more than 80 years, the population has remained small. The main causes of the non-recovery have been attributed to irregularities in the lemming cycle and increased competitions with the larger red fox. Through conservation actions including red fox culling and supplementary feeding, the population has started to recover in parts of its former distribution range. The Arctic fox is highly adapted to the lemming cycle and determine whether to reproduce or not and adjust the litter size relation to small rodent phase in combination with food abundance. In the small rodent increase phase, females produce litters equal to the peak phase, despite higher food abundance in the later. This overproduction of cubs can be selected for through a higher juvenile survival and reproductive value of cubs born in the increase phase compared to the other phases. The most important component affecting the reproductive value seem to be the survival during the first year after birth. In the small rodent increase phase 32% of the cubs survives their first year compared to 9% in the decrease phase. The Arctic fox in Scandinavia constitute an example of how a species can adapt their reproductive strategy to a fluctuating environment by adjustment of the reproduction.
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| 9. |
- Nyström, Veronica, 1979-
(författare)
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Studies of declining populations - temporal genetic analyses of two arctic mammals
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Many populations and species are threatened with extinction today. Understanding the extinction process and the factors behind population decline is therefore important. In this thesis, genetic analyses were performed on temporally spaced samples to investigate the demographic history and genetic effects of population reduction of two species: the arctic fox (Vulpes lagopus) and the woolly mammoth (Mammuthus primigenius). We used ancient DNA techniques to measure genetic variation in both mitochondrial DNA and microsatellites. In paper I, we investigated the genetic consequences of a human-induced demographic bottleneck in the Scandinavian arctic fox population. By comparing genetic data from museum specimens with genetic data from the contemporary population, we found a loss of genetic variation. However, the loss was less than expected, probably due to gene flow from North Russia. Using the same approach, we also found that Pleistocene arctic foxes from midlatitude Europe do not seem to have contributed to the genetic composition of contemporary populations (paper II). This suggests that they went extinct rather than track their habitat when it shifted northwards at the end of Pleistocene. Further, by analysing genetic data from radiocarbon dated fossils, we also found that the woolly mammoth lost genetic variation in connection to a marked decline in population size at the end of Pleistocene (paper III and IV). However, no further losses were detected during the time that mammoths were isolated on Wrangel Island, which suggests a rapid extinction process possibly caused by the arrival of humans or a short-term change in climate (paper III and IV). The results in this thesis demonstrate the usefulness of temporal genetic analyses for identifying population decline and evaluating its consequences.
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| 10. |
- Carlén, Ida, 1976-
(författare)
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Ecology and Conservation of the Baltic Proper Harbour Porpoise
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The Baltic Proper harbour porpoise (Phocoena phocoena) population is listed by IUCN as Critically Endangered, but conservation action has been lacking for decades, partly due to very limited knowledge on important ecological parameters such as distribution range and abundance. This thesis provides some of the information needed for implementing effective conservation. The seasonal distribution of harbour porpoises in the study area in the Baltic Sea is modelled based on two years of passive acoustic monitoring data. Results reveal an area of high probability of detection on and around the offshore banks in the Baltic Proper south of the island of Gotland in summer (May – October). This area is likely to be the most important breeding area for the Baltic Proper population given the concentration of animals during the summer reproductive season. A summer management border is identified for the population, going from Jarosławiec on the Polish coast to the inner Hanö Bay on the Swedish coast. The abundance of the population is estimated to 491 individuals (95% CI 71-1105), which confirms the redlist status of the population and underlines the need for immediate conservation measures. The conservation policy of the Baltic Proper harbour porpoise and other harbour porpoise populations in Europe is discussed, detailing the latest developments including the 2020 ICES scientific advice on bycatch mitigation for the Baltic Proper harbour porpoise and noting that the legal framework for protection is mostly present, but that there is still a lack of concrete conservation action. It is suggested that this failure to protect porpoises may be a result of low motivation for decision-makers to take action which in turn is likely due to some politically difficult prioritisations having to be made, in combination with the low public recognition of the harbour porpoise as a species throughout Europe. Suggestions are made for next steps.One technical solution to mitigating harbour porpoise bycatch is acoustic deterrent devices, pingers, which are placed on fishing nets to alert harbour porpoises to the presence of nets. However, in the Baltic there has been discussions that pingers work as dinner bells for seals, and fishermen have been hesitating to use them. Here, it is shown that high-frequency pingers do not cause an increase in seal depredation on static nets and hence that they are a viable solution for much needed bycatch mitigation within the distribution range of the Baltic Proper harbour porpoise population.
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| 11. |
- Granquist, Sandra
(författare)
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Harbour seals (Phoca Vitulina) and tourists in Iceland : Who´s watching who?
- 2013
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Wildlife tourism is at the moment a fast growing sector in the tourism industry. Therefore, there is a need for balancing the protecting of wildlife with the right of tourists and operators to use nature as a resource. Mutual exchange and acceptance of research results between biological- and tourism research has until recently been scarce. In this thesis, I have investigated interactions between harbour seals (Phoca vitulina) and tourists on Vatnsnes Peninsula, NW Iceland. In Paper I the effect of land-based seal watching on the haul-out behaviour and spatial distribution of harbour seals (Phoca vitulina) was investigated. In addition, the behaviour of tourists during seal watching was studied. The results showed that disturbance due to tourists caused an increased vigilance of the seals and affected their spatial distribution. The behaviour of tourists depended on group type with single tourists and couples behaving more passively compared to families and tourist groups of more than two adults. However, all tourist group types were significantly more active in an approaching zone than in the seal watching zone.The absence of discipline-independent guidance on how to manage wildlife tourism, in combination with a lack of knowledge-transfer from academia to the wildlife tourism sector regarding how human impact can be reduced, could contribute to unintended disturbance of wildlife. In Paper II we discuss how a synergetic gain of intergrading knowledge from different disciplines may occur and be implemented when it comes to managing wildlife tourism. We then present a method, where use and protection constitute equal interdisciplinary importance, when the aim is to create a sustainable relation between watchers and watched within wildlife tourism. The possibility is exemplified through an interdisciplinary academic approach, by combining the results found in Paper I with results derived from a tourist research study on the perception of tourists regarding wildlife. The combined results suggest that tourists do not always have a conscious idea of how to behave to minimise disturbance, underlining that focus should be put on education. We suggest how to transfer knowledge from academic research derived from the interdisciplinary approach to the industry through a teleological code of conduct.
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| 12. |
- Haage, Marianne, 1985-
(författare)
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Conservation, personality and ecology of the European mink (Mustela lutreola)
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Loss of biodiversity is a growing problem and hence conservation of species is becoming increasingly important. In this dissertation conservation issues related to the critically endangered European mink (Mustela lutreola) are examined in situ (in the wild) and ex situ (in captivity) on both an individual and community level. It also contains fundamental research as conservation contexts often allow for conclusions beyond applied biology. Individual behavioural differences, e.g. personality, can impact fitness and are hence relevant for conservation. Paper I thus experimentally explores the structure, expression and plasticity of personality in captive European minks. Thereafter paper II investigates if personality affects survival of reintroduced captive-bred animals and if spatiotemporal conditions affects the relationship between personality and survival. Paper III experimentally explores individual dietary specialism and learning in relation to novel prey as this could also impact survival. One of the main threats to the European mink is displacement by the invasive American mink (Neovison vison) wherefore management of American mink is important for European mink conservation. Paper IV hence analyses survey data to study whether native otters and red foxes can suppress American mink populations in north-eastern Europe. In the results three personality trait domains were identified in the European mink: boldness, exploration and sociability. The domains were repeatable but plastic between the non-breeding and breeding season. Reintroduced personality-tested animals survived longer if they were bolder but the effect of exploration was either positive or negative depending on spatiotemporal conditions. This is not only interesting for conservation but provides new insights on how individual behavioural differences could be maintained over evolutionary time. Whilst exploration is likely to be maintained by fluctuating selection pressures, the mechanism seem to vary with domain. The feeding experiments revealed diet choices similar to those found in wild individuals as there were both generalists and different types of specialists. Still, individuals differed in learning time towards novel but natural prey, suggesting that reintroduced animals might differ in their ability to find food after release. This could affect survival also and be related to personality. Survey data revealed that American mink abundances were suppressed by those of red foxes. Previous studies show that foxes are suppressed by lynx, and the abundance pattern of mink in relation to red fox found here indicate the existence of a predator cascade as mink were most abundant where lynx were abundant and vice versa. In several regions in the study area population dynamics indicated either exploitation or interference competition as probable mechanisms whereby foxes suppress minks. However, in many regions there were no relationships between dynamics. This could be due to that exploitation and interference competition might occur simultaneously and thus cancel each other out in the dynamics. Overall this thesis shows the importance of considering individual traits in conservation efforts, and also provides knowledge on the structure, plasticity and evolution of personality. As American mink was suppressed by foxes, management efforts might be most beneficial for species impacted by the mink if they to a larger extent are undertaken in areas with low fox abundances.
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| 13. |
- Särnblad Hansson, Anna, 1975-
(författare)
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Ecology and genetic population structure of Indo-Pacific bottlenose dolphins in East Africa
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Many marine mammal populations are threatened by anthropogenic activities. The Indo-Pacific bottlenose dolphins (Tursiops aduncus) off Zanzibar are subject to high levels of bycatch, negative impact from tourism and were previously hunted. To assess conservation status and to formulate necessary management actions for viable dolphin populations, knowledge of their population ecology is vital. This thesis provides information on population size, distribution, social structure, genetic diversity and population differentiation for Indo-Pacific bottlenose dolphins off southern Zanzibar. To investigate these parameters, individual identification and group structure data collected during boat based surveys were used in combination with genetic analyses of tissue samples from bycaught animals and skin biopsies from free ranging animals. The results show that the area off southern Zanzibar potentially constitute an important nursing ground (Paper I, II) for the relatively small population of Indo-Pacific bottlenose dolphins present year round (Paper I). The dolphins in this area live in a fission-fusion society where some animals also form long-term relationships (Paper II). Genetic analyses indicate limited exchange of reproducing females between northern and southern Zanzibar suggesting female philopatry with a greater dispersal by males (Paper III, IV). The relatively high genetic diversity of the Indo-Pacific bottlenose dolphins off Zanzibar indicates no current threat to their genetic health, despite recent anthropogenic impacts. (Paper IV). On a greater geographical scale the results show that the Indo-Pacific bottlenose dolphins in the western Indian Ocean, ranging from Oman to South Africa, share a relatively recent common founder population and belong to a proposed third species within the genus Tursiops (Paper III, IV). Finally, the results presented demonstrate the value of a multi-disciplinary approach to determine the conservation status of animal populations.
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