| 1. |
- Dietz, R., et al.
(författare)
-
The Baltic Sea: An ecosystem with multiple stressors
- 2021
-
Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 147
-
Tidskriftsartikel (refereegranskat)abstract
- © 2020 The Authors This introductory chapter to our Environment International VSI. Future work should examine waterbirds as food web sentinels of multiple stressors as well as Baltic Sea food web dynamics of hazardous substances and how climate change may modify it. Also, future work should aim at further extending the new frameworks developed within BALTHEALTH for energy and contaminant transfer at the population level (Desforges et al., 2018, Cervin et al., 2020/this issue Silva et al., 2020/this issue) and their long term effects on Baltic Sea top predators, such as harbour porpoises, grey seals ringed seals, and white-tailed eagles. Likewise, the risk evaluation conducted for PCB in connection with mercury on Arctic wildlife (Dietz et al., 2019, not a BONUS BALTHEALTH product) could be planned for Baltic Sea molluscs, fish, bird and marine mammals in the future. Finally, future efforts could include stressors not covered by the BONUS BALTHEALTH project, such as food web fluxes, overexploitation, bycatches, eutrophication and underwater noise.
|
|
| 2. |
- Johannesson, Kerstin, 1955, et al.
(författare)
-
Ten years of marine evolutionary biology - challenges and achievements of a multidisciplinary research initiative
- 2023
-
Ingår i: Evolutionary Applications. - : Wiley. - 1752-4571. ; 16:2, s. 530-41
-
Tidskriftsartikel (refereegranskat)abstract
- The Centre for Marine Evolutionary Biology (CeMEB) at the University of Gothenburg, Sweden, was established in 2008 through a 10-year research grant of 8.7 m€ to a team of senior researchers. Today, CeMEB members have contributed >500 scientific publications, 30 PhD theses and have organised 75 meetings and courses, including 18 three-day meetings and four conferences. What are the footprints of CeMEB, and how will the centre continue to play a national and international role as an important node of marine evolutionary research? In this perspective arcticle we first look back over the 10 years of CeMEB activities and briefly survey some of the many achievements of CeMEB. We furthermore compare the initial goals, as formulated in the grant application, with what has been achieved, and discuss challenges and milestones along the way. Finally, we bring forward some general lessons that can be learnt from a research funding of this type, and we take also look ahead, discussing how CeMEB’s achievements and lessons can be used as a springboard to the future of marine evolutionary biology.
|
|
| 3. |
- Liu, X. D., et al.
(författare)
-
Origin and expansion of the world's most widespread pinniped: Range-wide population genomics of the harbour seal (Phoca vitulina)
- 2022
-
Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 31:6, s. 1682-1699
-
Tidskriftsartikel (refereegranskat)abstract
- The harbour seal (Phoca vitulina) is the most widely distributed pinniped, occupying a wide variety of habitats and climatic zones across the Northern Hemisphere. Intriguingly, the harbour seal is also one of the most philopatric seals, raising questions as to how it colonized its current range. To shed light on the origin, remarkable range expansion, population structure and genetic diversity of this species, we used genotyping-by-sequencing to analyse similar to 13,500 biallelic single nucleotide polymorphisms from 286 individuals sampled from 22 localities across the species' range. Our results point to a Northeast Pacific origin of the harbour seal, colonization of the North Atlantic via the Canadian Arctic, and subsequent stepping-stone range expansions across the North Atlantic from North America to Europe, accompanied by a successive loss of genetic diversity. Our analyses further revealed a deep divergence between modern North Pacific and North Atlantic harbour seals, with finer-scale genetic structure at regional and local scales consistent with strong philopatry. The study provides new insights into the harbour seal's remarkable ability to colonize and adapt to a wide range of habitats. Furthermore, it has implications for current harbour seal subspecies delineations and highlights the need for international and national red lists and management plans to ensure the protection of genetically and demographically isolated populations.
|
|
| 4. |
- Naepflin, Kathrin, et al.
(författare)
-
Genomics of host-pathogen interactions: challenges and opportunities across ecological and spatiotemporal scales
- 2019
-
Ingår i: PeerJ. - 2167-8359. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- Evolutionary genomics has recently entered a new era in the study of host-pathogen interactions. A variety of novel genomic techniques has transformed the identification, detection and classification of both hosts and pathogens, allowing a greater resolution that helps decipher their underlying dynamics and provides novel insights into their environmental context. Nevertheless, many challenges to a general understanding of host-pathogen interactions remain, in particular in the synthesis and integration of concepts and findings across a variety of systems and different spatiotemporal and ecological scales. In this perspective we aim to highlight some of the commonalities and complexities across diverse studies of host-pathogen interactions, with a focus on ecological, spatiotemporal variation, and the choice of genomic methods used. We performed a quantitative review of recent literature to investigate links, patterns and potential tradeoffs between the complexity of genomic, ecological and spatiotemporal scales undertaken in individual host-pathogen studies. We found that the majority of studies used whole genome resolution to address their research objectives across a broad range of ecological scales, especially when focusing on the pathogen side of the interaction. Nevertheless, genomic studies conducted in a complex spatiotemporal context are currently rare in the literature. Because processes of host-pathogen interactions can be understood at multiple scales, from molecular-, cellular-, and physiological-scales to the levels of populations and ecosystems, we conclude that a major obstacle for synthesis across diverse host-pathogen systems is that data are collected on widely diverging scales with different degrees of resolution. This disparity not only hampers effective infrastructural organization of the data but also data granularity and accessibility. Comprehensive metadata deposited in association with genomic data in easily accessible databases will allow greater inference across systems in the future, especially when combined with open data standards and practices. The standardization and comparability of such data will facilitate early detection of emerging infectious diseases as well as studies of the impact of anthropogenic stressors, such as climate change, on disease dynamics in humans and wildlife.
|
|
| 5. |
- Näpflin, Kathrin, et al.
(författare)
-
Genomics of host-pathogen interactions: challenges and opportunities across ecological and spatiotemporal scales
- 2019
-
Ingår i: PeerJ. - : PeerJ. - 2167-8359. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- Evolutionary genomics has recently entered a new era in the study of host-pathogen interactions. A variety of novel genomic techniques has transformed the identification, detection and classification of both hosts and pathogens, allowing a greater resolution that helps decipher their underlying dynamics and provides novel insights into their environmental context. Nevertheless, many challenges to a general understanding of host-pathogen interactions remain, in particular in the synthesis and integration of concepts and findings across a variety of systems and different spatiotemporal and ecological scales. In this perspective we aim to highlight some of the commonalities and complexities across diverse studies of host-pathogen interactions, with a focus on ecological, spatiotemporal variation, and the choice of genomic methods used. We performed a quantitative review of recent literature to investigate links, patterns and potential tradeoffs between the complexity of genomic, ecological and spatiotemporal scales undertaken in individual host-pathogen studies. We found that the majority of studies used whole genome resolution to address their research objectives across a broad range of ecological scales, especially when focusing on the pathogen side of the interaction. Nevertheless, genomic studies conducted in a complex spatiotemporal context are currently rare in the literature. Because processes of host-pathogen interactions can be understood at multiple scales, from molecular-, cellular-, and physiological-scales to the levels of populations and ecosystems, we conclude that a major obstacle for synthesis across diverse host-pathogen systems is that data are collected on widely diverging scales with different degrees of resolution. This disparity not only hampers effective infrastructural organization of the data but also data granularity and accessibility. Comprehensive metadata deposited in association with genomic data in easily accessible databases will allow greater inference across systems in the future, especially when combined with open data standards and practices. The standardization and comparability of such data will facilitate early detection of emerging infectious diseases as well as studies of the impact of anthropogenic stressors, such as climate change, on disease dynamics in humans and wildlife.
|
|
| 6. |
- Sonne, C., et al.
(författare)
-
Health effects from contaminant exposure in Baltic Sea birds and marine mammals: A review
- 2020
-
Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 139
-
Tidskriftsartikel (refereegranskat)abstract
- Here we review contaminant exposure and related health effects in six selected Baltic key species. Sentinel species included are common eider, white-tailed eagle, harbour porpoise, harbour seal, ringed seal and grey seal. The review represents the first attempt of summarizing available information and baseline data for these biomonitoring key species exposed to industrial hazardous substances focusing on anthropogenic persistent organic pollutants (POPs). There was only limited information available for white-tailed eagles and common eider while extensive information exist on POP exposure and health effects in the four marine mammal species. Here we report organ-tissue endpoints (pathologies) and multiple biomarkers used to evaluate health and exposure of key species to POPs, respectively, over the past several decades during which episodes of significant population declines have been reported. Our review shows that POP exposure affects the reproductive system and survival through immune suppression and endocrine disruption, which have led to population-level effects on seals and white-tailed eagles in the Baltic. It is notable that many legacy contaminants, which have been banned for decades, still appear to affect Baltic wildlife. With respect to common eiders, changes in food composition, quality and contaminant exposure seem to have population effects which need to be investigated further, especially during the incubation period where the birds fast. Since new industrial contaminants continuously leak into the environment, we recommend continued monitoring of them in sentinel species in the Baltic, identifying possible effects linked to climate change, and modelling of population level effects of contaminants and climate change. © 2020 The Authors
|
|
| 7. |
- Stephens, P. A., et al.
(författare)
-
The scaling of diving time budgets: Insights from an optimality approach
- 2008
-
Ingår i: American Naturalist. - : University of Chicago Press. - 0003-0147 .- 1537-5323. ; 171:3, s. 305-314
-
Tidskriftsartikel (refereegranskat)abstract
- Simple scaling arguments suggest that, among air-breathing divers, dive duration should scale approximately with mass to the one-third power. Recent phylogenetic analyses appear to confirm this. The same analyses showed that duration of time spent at the surface between dives has scaling very similar to that of dive duration, with the result that the ratio of dive duration to surface pause duration is approximately mass invariant. This finding runs counter to other arguments found in the diving literature that suggest that surface pause duration should scale more positively with mass, leading to a negative scaling of the dive-pause ratio. We use a published model of optimal time allocation in the dive cycle to show that optimal decisions can predict approximate mass invariance in the dive-pause ratio, especially if metabolism scales approximately with mass to the two-thirds power (as indicated by some recent analyses) and oxygen uptake is assumed to have evolved to supply the body tissues at the required rate. However, emergent scaling rules are sensitive to input parameters, especially to the relationship between the scaling of metabolism and oxygen uptake rate at the surface. Our results illustrate the utility of an optimality approach for developing predictions and identifying key areas for empirical research on the allometry of diving behavior.
|
|
| 8. |
- Arcalis-planas, A., et al.
(författare)
-
Limited use of sea ice by the Ross seal (Ommatophoca rossii), in Amundsen Sea, Antarctica, using telemetry and remote sensing data
- 2015
-
Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 38:4, s. 445-461
-
Tidskriftsartikel (refereegranskat)abstract
- To understand the use and importance of the Antarctic sea ice to the Ross seal (Ommatophoca rossii), four adult females were tagged with Argos satellite transmitters in the Amundsen Sea, Antarctica. The Ross seal is the least studied of the Antarctic seal species and nothing was previously known about their behaviour in the Amundsen Sea. During almost 1 year, their movements, haul out behaviour and time spent at different temperatures were logged. By comparing their movements with daily ice maps, distances to the ice edge were calculated, and seals dependence on sea ice for resting, breeding and moulting was analysed. The tagged seals spent on average 70.8 % (range 66.8–77.8 %) of their time in the water and hauled out mainly during the moult in December–January, and in late October–mid-November during breeding. During the pelagic period, they were on average 837.5 km (range 587–1,282 km) from the ice edge indicating a fully pelagic life during several months. Their pelagic behaviour suggests that Ross seals, although being an ice obligate species, may adapt comparatively easy to climate change involving ice melting and recession and thereby potentially being less sensitive to the reduction of sea ice than other Antarctic seal species. Although nothing is known about their mating behaviour, they appear to be relatively stationary during moulting and breeding, hence requiring a small ice surface. Although previous studies in other parts of Antarctica have found similar results, still many questions remain about this peculiar species.
|
|
| 9. |
- Brault, Emily K., et al.
(författare)
-
Trophic position and foraging ecology of Ross, Weddell, and crabeater seals revealed by compound-specific isotope analysis
- 2019
-
Ingår i: Marine Ecology Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 611, s. 1-18
-
Tidskriftsartikel (refereegranskat)abstract
- © The authors 2019. Ross seals Ommatophoca rossii are one of the least studied marine mammals, with little known about their foraging ecology. Research to date using bulk stable isotope analysis suggests that Ross seals have a trophic position intermediate between that of Weddell Leptonychotes weddellii and crabeater Lobodon carcinophaga seals. However, consumer bulk stable isotope values not only reflect trophic dynamics, but also variations in baseline isotope values, which can be substantial. We used compound-specific isotope analysis of amino acids (CSI-AA) to separate isotopic effects of a shifting baseline versus trophic structure on the foraging ecology of these ecologically important Antarctic pinnipeds. We found that Ross seals forage in an open ocean food web, while crabeater and Weddell seals forage within similar food webs closer to shore. However, isotopic evidence suggests that crabeater seals are likely following sea ice, while Weddell seals target productive areas of the continental shelf of West Antarctica. Our CSI-AA data indicate that Ross seals have a high trophic position equivalent to that of Weddell seals, contrary to prior conclusions from nitrogen isotope results on bulk tissues. CSI-AA indicates that crabeater seals are at a trophic position lower than that of Ross and Weddell seals, consistent with a krill-dominated diet. Our results redefine the view of the trophic dynamics and foraging ecology of the Ross seal, and also highlight the importance of quantifying baseline isotope variations in foraging studies.
|
|
| 10. |
- Carroll, Daire, et al.
(författare)
-
120-years of ecological monitoring data shows that the risk of overhunting is increased by environmental degradation for an isolated marine mammal population: The Baltic grey seal
- 2024
-
Ingår i: Journal of Animal Ecology. - 0021-8790 .- 1365-2656. ; 93, s. 525-539
-
Tidskriftsartikel (refereegranskat)abstract
- The Baltic Sea is home to a genetically isolated and morphologically distinct grey seal population. This population has been the subject of 120-years of careful documentation, from detailed records of bounty statistics to annual monitoring of health and abundance. It has also been exposed to a range of well-documented stressors, including hunting, pollution and climate change. To investigate the vulnerability of marine mammal populations to multiple stressors, data series relating to the Baltic grey seal population size, hunt and health were compiled, vital demographic rates were estimated, and a detailed population model was constructed. The Baltic grey seal population fell from approximately 90,000 to as few as 3000 individuals during the 1900s as the result of hunting and pollution. Subsequently, the population has recovered to approximately 55,000 individuals. Fertility levels for mature females have increased from 9% in the 1970s to 86% at present. The recovery of the population has led to demands for increased hunting, resulting in a sudden increase in annual quotas from a few hundred to 3550 in 2020. Simultaneously, environmental changes, such as warmer winters and reduced prey availability due to overfishing, are likely impacting fecundity and health. Future population development is projected for a range of hunting and environmental stress scenarios, illustrating how hunting, in combination with environmental degradation, can lead to population collapse. The current combined hunting quotas of all Baltic Nations caused a 10% population decline within three generations in 100% of simulations. To enable continued recovery of the population, combined annual quotas of less than 1900 are needed, although this quota should be re-evaluated annually as monitoring of population size and seal health continues. Sustainable management of long-lived slowly growing species requires an understanding of the drivers of population growth and the repercussions of management decisions over many decades. The case of the Baltic grey seal illustrates how long-term ecological time series are pivotal in establishing historical baselines in population abundance and demography to inform sustainable management.
|
|
| 11. |
- Cervin, Linnea, et al.
(författare)
-
Multiple stressors and data deficient populations; a comparative life-history approach sheds new light on the extinction risk of the highly vulnerable Baltic harbour porpoises (Phocoena phocoena).
- 2020
-
Ingår i: Environment international. - : Elsevier BV. - 1873-6750 .- 0160-4120. ; 144
-
Tidskriftsartikel (refereegranskat)abstract
- Many endangered marine mammal populations are difficult to study, spread out over large areas, and capturing them for branding and research purposes would be unethical. Yet, they are in urgent need for assessment and conservation actions. We suggest collecting data from other more abundant populations of the same species, with careful consideration of body size, age at sexual maturity, and ecological conditions to produce scientifically sound best approximations of vital rates of data deficient endangered populations. The genetically distinct Baltic Sea harbour porpoise population amounts to about 500 animals and is classified as 'Critically Endangered' according to the IUCN red list. Data deficiency on nearly all demographic parameters have precluded systematic investigations of the relative importance of stressors affecting population viability. We took a comparative life history approach and investigated the phenotypic plasticity in somatic and demographic vital rates of seven larger, well studied North Atlantic harbour porpoise populations, enabling us to approximate the missing pieces of the life history of the Baltic population. We parameterized a stochastic, individual-based population model, and performed a population viability analysis for a range of biologically realistic parameter values and scenarios of environmental stressors. The baseline scenario was based on the most representative samples of healthy harbour porpoise populations and challenged with three different levels of bycatches. Due to high levels of endocrine disruptive contaminants observed in Baltic harbour porpoises, we also investigated the effect of a possible reduction in fecundity. Subsequently, the combined effects of bycatches and reduced fecundity were investigated in terms of population growth rate and quasi-extinction risk. The Baltic harbour porpoise population is viable in the baseline scenario without anthropogenic stressors. However, even the lowest estimated bycatch level of 7 individuals per year will lead to a population collapse to ≤50 animals with high probability (0.4-1.0) over the next century, assuming an intermediate or low (<73%) fecundity. Adult survival is of critical importance and mitigation of fishery impacts and reduction of anthropogenic disturbances in the identified main breeding areas are recommended.
|
|
| 12. |
- Garde, E., et al.
(författare)
-
Life history parameters of narwhals (Monodon monoceros) from Greenland
- 2015
-
Ingår i: Journal of Mammalogy. - : Oxford University Press (OUP). - 0022-2372 .- 1545-1542. ; 96:4, s. 866-879
-
Tidskriftsartikel (refereegranskat)abstract
- Life history parameters for narwhals (Monodon monoceros) were estimated based on age estimates from aspartic acid racemization of eye lens nuclei. Eyes, reproductive organs, and measures of body lengths were collected from 282 narwhals in East and West Greenland in the years 1993, 2004, and 2007-2010. Age estimates were based on the racemization of L-aspartic acid to D-aspartic acid in the nucleus of the eye lens. The ratio of D- and L-enantiomers was measured using high-performance liquid chromatography. The age equation used, 420.32X - 24.02 center dot year where X is the D/L ratio, was determined from data from Garde et al. (2012). Asymptotic body length was estimated to be 405 +/- 5.8cm for females and 462 +/- 16.2cm for males from East Greenland, and 399 +/- 5.9cm for females and 456 +/- 6.9cm for males from West Greenland. Due to several indeterminant age class estimates, age at sexual maturity was subjectively assessed based on data from reproductive organs and was estimated to be 8-9 years for females and 12-20 years for males. Pregnancy rates for East and West Greenland were estimated to be 0.38-0.42 and 0.38, respectively. Maximum life span expectancy was found to be approximately 100 years. A population projection matrix was parameterized with the data on age structure and fertility rates. The annual rate of increase of narwhals in East Greenland was estimated to be 3.8% while narwhals in West Greenland had a rate of increase at 2.6%.
|
|
| 13. |
- Garnier, Romain, et al.
(författare)
-
Length of intervals between epidemics: evaluating the influence of maternal transfer of immunity
- 2014
-
Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 4:5, s. 568-575
-
Tidskriftsartikel (refereegranskat)abstract
- The length of intervals between epidemic outbreaks of infectious diseases is critical in epidemiology. In several species of marine mammals and birds, it is pivotal to also consider the life history of the species of concern, as the contact rate between individuals can have a seasonal flux, for example, due to aggregations during the breeding season. Recently, particular interest has been given to the role of the dynamics of immunity in determining the intervals between epidemics in wild animal populations. One potentially powerful, but often neglected, process in this context is the maternal transfer of immunity. Here, we explore theoretically how the transfer of maternal antibodies can delay the recurrence of epidemics using Phocine Distemper in harbor seals as an example of a system in which epidemic outbreaks are followed by pathogen extinction. We show that the presence of temporarily protected newborns can significantly increase the predicted interval between epidemics, and this effect is strongly dependent on the degree of synchrony in the breeding season. Furthermore, we found that stochasticity in the onset of epidemics in combination with maternally acquired immunity increases the predicted intervals between epidemics even more. These effects arise because newborns with maternal antibodies temporarily boost population level immunity above the threshold of herd immunity, particularly when breeding is synchronous. Overall, our results show that maternal antibodies can have a profound influence on the dynamics of wildlife epidemics, notably in gregarious species such as many marine mammals and seabirds.
|
|
| 14. |
|
|
| 15. |
- Harding, Karin C., 1968, et al.
(författare)
-
A unifying framework for metapopulation dynamics.
- 2002
-
Ingår i: The American Naturalist. - : University of Chicago Press. - 1537-5323 .- 0003-0147. ; 160:2, s. 173-185
-
Tidskriftsartikel (refereegranskat)abstract
- Many biologically important processes, such as genetic differentiation, the spread of disease, and population stability, are affected by the (natural or enforced) subdivision of populations into networks of smaller, partly isolated, subunits. Such "metapopulations" can have extremely complex dynamics. We present a new general model that uses only two functions to capture, at the metapopulation scale, the main behavior of metapopulations. We show how complex, structured metapopulation models can be translated into our generalized framework. The metapopulation dynamics arising from some important biological processes are illustrated: the rescue effect, the Allee effect, and what we term the "antirescue effect." The antirescue effect captures instances where high migration rates are deleterious to population persistence, a phenomenon that has been largely ignored in metapopulation conservation theory. Management regimes that ignore a significant antirescue effect will be inadequate and may actually increase extinction risk. Further, consequences of territoriality and conspecific attraction on metapopulation-level dynamics are investigated. The new, simplified framework can incorporate knowledge from epidemiology, genetics, and population biology in a phenomenological way. It opens up new possibilities to identify and analyze the factors that are important for the evolution and persistence of the many spatially subdivided species.
|
|
| 16. |
- Harding, Karin C., 1968, et al.
(författare)
-
Acquired immunity and stochasticity in epidemic intervals impede the evolution of host disease resistance
- 2005
-
Ingår i: American Naturalist. - : University of Chicago Press. - 0003-0147 .- 1537-5323. ; 166:6, s. 722-730
-
Tidskriftsartikel (refereegranskat)abstract
- Disease can generate intense selection pressure on host populations, but here we show that acquired immunity in a population subject to repeated disease outbreaks can impede the evolution of genetic disease resistance by maintaining susceptible genotypes in the population. Interference between the life-history schedule of a species and periodicity of the disease has unintuitive effects on selection intensity, and stochasticity in outbreak period further reduces the rate of spread of disease-resistance alleles. A general age-structured population genetic model was developed and parameterized using empirical data for phocine distemper virus (PDV) epizootics in harbor seals. Scenarios with acquired immunity had lower levels of epizootic mortality compared with scenarios without acquired immunity for the first PDV outbreaks, but this pattern was reversed after about five disease cycles. Without acquired immunity, evolution of disease resistance was more rapid, and long-term population size variation is efficiently dampened. Acquired immunity has the potential to significantly influence rapid evolutionary dynamics of a host population in response to age-structured disease selection and to alter predicted selection intensities compared with epidemiological models that do not consider such feedback. This may have important implications for evolutionary population dynamics in a range of human, agricultural, and wildlife disease settings.
|
|
| 17. |
|
|
| 18. |
|
|
| 19. |
- Harding, Karin C., 1968, et al.
(författare)
-
Increased migration in host–pathogen metapopulations can cause host extinction
- 2012
-
Ingår i: Journal of Theoretical Biology. - : Elsevier BV. - 1095-8541 .- 0022-5193. ; 298, s. 1-7
-
Tidskriftsartikel (refereegranskat)abstract
- There are at least two potentially counteracting effects of migration in host–pathogen metapopulations. On the one hand increased migration leads to increased colonization of empty habitats by healthy hosts; on the other hand migrants can carry infectious diseases to susceptible populations. Earlier metapopulation models have found that the beneficial effects of increasing migration (reduced infection) are likely to dominate, and a general recommendation for managers of endangered metapopulations has been to increase connectivity between habitat patches. We extend the model framework to simultaneously allow for (1) Allee effects in host colonization rate, (2) spillover of pathogens from a second host species, and (3) differential colonization success by infected and healthy hosts. We find that the dynamics of a host–pathogen system can be highly sensitive to increased migration rates. Allee effects make host populations vulnerable to spillover of pathogens from other hosts, and metapopulation extinction can emerge from seemingly stable situations of endemic coexistence. Increasing connectivity in endangered metapopulations can be a risky management action unless the details of the biology of the host–pathogen system are known.
|
|
| 20. |
|
|
| 21. |
- Harding, Karin C., 1968, et al.
(författare)
-
Population Wide Decline in Somatic Growth in Harbor Seals—Early Signs of Density Dependence
- 2018
-
Ingår i: Frontiers in Ecology and the Environment. - : Frontiers Media SA. - 1540-9295 .- 1540-9309 .- 2296-701X. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- The harbor seal populations of Danish and Swedish waters have had turbulent population dynamics during the last century. They were severely depleted by hunting in the beginning of the twentieth century, followed by rapid recovery due to protective measures. They were victims to two mass mortalities caused by Phocine Distemper Virus (PDV) epidemics. Long term monitoring and intensive sampling during the last decades now allow analysis of population level phenomena in response to shifting population size. We compare somatic growth curves from several seal populations including 2,041 specimens with known age, length and population size at birth. Asymptotic body lengths of female harbor seals were 148 cm in all four regions in 1988, when seal abundances had been kept low by hunting for decades. Males were 158 cm, being 10 cm longer. However, in 2002 the asymptotic lengths of seals differed among regions. While seals in the Kattegat showed similar asymptotic lengths as in 1988, seals in the Skagerrak were significantly shorter, where both male and female asymptotic lengths declined by 7 cm. We estimate the area of available feeding grounds in the two sea regions and find the density of seals per square kilometer feeding ground to be three times greater in the Skagerrak compared to the Kattegat. Thus, the shorter body length of seals in the Skagerrak can be an early signal of density dependence. Hampered body growth is known to trigger a suite of changes in life history traits, including delayed age at sexual maturity, higher juvenile mortality and lowered fecundity. These mechanisms all point at a possible “smooth route toward carrying capacity” with gradually reduced population growth rate as the main response to high population density. Recent aerial surveys confirm declining rates of population increase in the Skagerrak.
|
|
| 22. |
|
|
| 23. |
- Harding, Karin C., 1968, et al.
(författare)
-
The 2002 European seal plague: epidemiology and population consequences
- 2002
-
Ingår i: Ecology Letters. - 1461-023X. ; 5:6, s. 727-732
-
Tidskriftsartikel (refereegranskat)abstract
- We present the first epidemiological data on the 2002 outbreak of phocine distemper virus (PDV) in European harbour seals (Phoca vitulina). The epizootic curve to date supports a mortality rate and probability of infection identical to that of the 1988 outbreak, which killed 58% of the population. Thus immunity is playing no significant role in the dynamics of the current outbreak. Because the timing of the outbreak is important in determining local mortality rates, we predict higher mortality rates on the European continent than in Great Britain or Ireland. A stochastic model is used to quantify how recurrent epizootics affect the long-term growth, fluctuation, and persistence of the population. Recurrent PDV epizootics with the observed frequency and severity would reduce the long-term stochastic growth rate of the harbour seal population by half, and significantly increase the risk of quasi-extinction.
|
|
| 24. |
|
|
| 25. |
- Harkonen, Tero, et al.
(författare)
-
Age- and sex-specific mortality patterns in an emerging wildlife epidemic: the phocine distemper in European harbour seals.
- 2007
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 2:9
-
Tidskriftsartikel (refereegranskat)abstract
- Analyses of the dynamics of diseases in wild populations typically assume all individuals to be identical. However, profound effects on the long-term impact on the host population can be expected if the disease has age and sex dependent dynamics. The Phocine Distemper Virus (PDV) caused two mass mortalities in European harbour seals in 1988 and in 2002. We show the mortality patterns were highly age specific on both occasions, where young of the year and adult (>4 yrs) animals suffered extremely high mortality, and sub-adult seals (1-3 yrs) of both sexes experienced low mortality. Consequently, genetic differences cannot have played a main role explaining why some seals survived and some did not in the study region, since parents had higher mortality levels than their progeny. Furthermore, there was a conspicuous absence of animals older than 14 years among the victims in 2002, which strongly indicates that the survivors from the previous disease outbreak in 1988 had acquired and maintained immunity to PDV. These specific mortality patterns imply that contact rates and susceptibility to the disease are strongly age and sex dependent variables, underlining the need for structured epidemic models for wildlife diseases. Detailed data can thus provide crucial information about a number of vital parameters such as functional herd immunity. One of many future challenges in understanding the epidemiology of the PDV and other wildlife diseases is to reveal how immune system responses differ among animals in different stages during their life cycle. The influence of such underlying mechanisms may also explain the limited evidence for abrupt disease thresholds in wild populations.
|
|
| 26. |
- Harkonen, T., et al.
(författare)
-
Collapse of a Marine Mammal Species Driven by Human Impacts
- 2012
-
Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 7:9
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding historical roles of species in ecosystems can be crucial for assessing long term human impacts on environments, providing context for management or restoration objectives, and making conservation evaluations of species status. In most cases limited historical abundance data impedes quantitative investigations, but harvested species may have long-term data accessible from hunting records. Here we make use of annual hunting records for Caspian seals (Pusa caspica) dating back to the mid-19th century, and current census data from aerial surveys, to reconstruct historical abundance using a hind-casting model. We estimate the minimum numbers of seals in 1867 to have been 1-1.6 million, but the population declined by at least 90% to around 100,000 individuals by 2005, primarily due to unsustainable hunting throughout the 20th century. This collapse is part of a broader picture of catastrophic ecological change in the Caspian over the 20th Century. Our results combined with fisheries data show that the current biomass of top predators in the Caspian is much reduced compared to historical conditions. The potential for the Caspian and other similar perturbed ecosystems to sustain natural resources of much greater biological and economic value than at present depends on the extent to which a number of anthropogenic impacts can be harnessed.
|
|
| 27. |
- Harkonen, Tero, et al.
(författare)
-
Seasonal activity budget of adult baltic ringed seals.
- 2008
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 3:4
-
Tidskriftsartikel (refereegranskat)abstract
- Although ringed seals are important components in oceanic and fresh water ecosystems at high latitudes, little is known about how they exploit these harsh environments. Seasonal activity and diving behaviour of 19 adult Baltic ringed seals were studied by satellite telemetry. We elaborated an activity budget for ten months of the year, extending over the period from moult to the breeding season. Seals from three main regions showed explicit site fidelity and the distributions of animals tagged from different areas did not overlap, suggesting separate stocks. Both the mean duration and the mean depth of dives peaked in June and July. Seals spent 70% (females) to 85% (males) of their time diving in June and July which decreased to 50% in late autumn. Less than one percent of dives exceeded 10 min in females, while 10% of male dives lasted longer than 10 min in June to September. Less than one percent of dives lasted for more than 25 min. Both females and males were most active during day time and hauled out predominantly during the night. Activity patterns during the summer are suggested to be correlated to energy accumulation and prey availability. The information on seasonal activity budget is crucial for developing population energetic models where interactions between ringed seals and other trophic levels can be evaluated.
|
|
| 28. |
- Heide-Jørgensen, Mads Peter, et al.
(författare)
-
Rate of increase and current abundance of humpback whales in West Greenland.
- 2012
-
Ingår i: Journal of Cetacean Research and Management. - 1561-0713. ; 12, s. 1-14
-
Tidskriftsartikel (refereegranskat)abstract
- Aerial line transect surveys of the density of humpback whales (Megaptera novaeangliae) conducted off West Greenland eight times between 1984 and 2007 were used to estimate the rate of increase on the summer feeding ground. Only surveys in 1993, 2005 and 2007 had enough sightings to construct independent density estimates, whereas the surveys in 1984–85 and 1987–89 had to be merged and treated as two surveys. The annual rate of increase was 9.4% yr–1 (SE = 0.01) between 1984 and 2007. This rate of increase is higher than the increase estimated at the breeding grounds in the West Indies, but is of the same magnitude as the observed rate of increase at other feeding grounds in the North Atlantic. A matrix model based on observed life history parameters revealed that the theoretical growth rate of a humpback whale population ranged between 1 and 11%. This confirms that the observed growth in West Greenland is within the plausible values. The survey in 2007 was used to make a fully corrected abundance estimate including corrections for whales that were submerged during the passage of the survey plane. The line transect estimate for 2007 was 1,020 (CV = 0.35). When the estimate was corrected for perception bias with mark-recapture distance sampling (MRDS) methods, the abundance increased to 1,505 (0.49). A correction for availability bias was developed based on time-depth-recorder information on the time spent at the surface (0–4m). However, used directly this correction leads to a positively-biased abundance estimate and instead a correction was developed for the non-instantaneous visual sighting process in an aircraft. The resulting estimate for 2007 was 3,272 (CV = 0.50) for the MRDS analysis. An alternative strip census estimate deploying a strip width of 300m resulted in 995 (0.33) whales. Correction for perception bias resulted in 991 (0.35) whales and corrected for the same availability bias as for the MRDS method resulted in a fully corrected estimate of 2,154 (0.36) humpback whales in West Greenland in 2007.
|
|
| 29. |
|
|
| 30. |
- Härkönen, T., et al.
(författare)
-
Colonization history of the baltic harbor seals: Integrating archaeological, behavioral, and genetic data
- 2005
-
Ingår i: Marine Mammal Science. - : Wiley. - 0824-0469 .- 1748-7692. ; 21:4, s. 695-716
-
Tidskriftsartikel (refereegranskat)abstract
- Detailed knowledge about the history of colonization, population dynamics and behavior greatly enhance evaluation of genetic models of population units and migration rates in spatially structured populations. Here, the genetic uniqueness of harbor seals (Phoca vitulina) in the eastern Baltic is evaluated in the light of new information on the distribution and abundance of Baltic and eastern North Sea populations during the last 11,000 yr, recent hunting statistics, and population counts. Archaeological records reveal that the Baltic population of harbor seals was founded about 8,000 yr ago. Adjacent populations in the North Sea areas were either small, or went extinct, and became significant only during the last 300 yr. This information generates the hypothesis that the Baltic population has been isolated during the last 8,000 yr, despite the lack of geographical barriers. We show that stochastic effects, isolation, and a documented recent population bottleneck can account for the low observed genetic variation in Baltic harbor seals.
|
|
| 31. |
|
|
| 32. |
- Härkönen, Tero, et al.
(författare)
-
Predicting recurrent PDV epizootics in European harbour seals (Phoca vitulina)
- 2010
-
Ingår i: NAMMCO scientific publications. - 1560-2206. ; 8, s. 275-284
-
Tidskriftsartikel (refereegranskat)abstract
- Phocine Distemper Virus (PDV) caused mass mortality in European harbour seals (Phoca vitulina) in 1988 and in 2002. Both epizootics likely originated from refugia in Arctic seals, where data indicate PDV hops among populations and species. The metapopulation structure of host populations is suggested to be the reason why PDV is preserved among Arctic seals, since the high rate of spread of PDV would require much larger panmictic populations to maintain an infection. The pattern of sudden outbreaks of PDVi s also seen in grey seals (Halichoerus grypus), the only to date identified species that could act as a vector between Arctic and North Sea seal populations. Harbour seal populations along mainland Europe were below critical herd immunity levels by 3-5 years after the events, and thus vulnerable for new outbreaks, but historical data and the 14 years between the 2 epizootics suggest that harbour seals in the North Sea area are only rarely exposed to the infective agent. The risk for new outbreaks of the seal plague in North Sea harbour seals is likely linked to the dynamics of the disease in Arctic seal species as well as vector species.
|
|
| 33. |
- Härkönen, T., et al.
(författare)
-
Rates of increase in age-structured populations: a lesson from the European harbour seals
- 2002
-
Ingår i: Canadian Journal of Zoology-Revue Canadienne De Zoologie. - 0008-4301. ; 80:9, s. 1498-1510
-
Tidskriftsartikel (refereegranskat)abstract
- Behavioural differences among population segments coupled with the transient dynamics of perturbed population structures lead to severely biased estimates of the intrinsic rates of increase in natural populations. This phenomenon is expected to occur in most populations that are structured by age, sex, state, or rank. The 1988 epizootic in European harbour seals (Phoca vitulina) perturbed the population composition radically. Detailed documentation of mass mortality, 20 years of population surveys, and data on age- and sex-specific behaviour were used to quantify biases in the observed rate of increase (lambda(obs.)), which in many areas substantially exceeded the "maximum rate of increase". This is serious, since lambda(obs.) is a key parameter, for example, in estimating potential biological removal or modelling population dynamics. For populations where the underlying age and sex composition is unknown, we suggest that data on fecundity and survival rates be used to find the upper theoretical rate of population increase. We found that the intrinsic rates of increase (lambda(1)) in populations of true seals with even sex ratios and stable age structures cannot exceed 13% per year (lambda(1max.) = 1.13). Frequently reported larger values are indicative of nonstable population structures or populations affected by migrations.
|
|
| 34. |
|
|
| 35. |
|
|
| 36. |
- Infantes, Eduardo, et al.
(författare)
-
An automated work-flow for pinniped surveys: A new tool for monitoring population dynamics
- 2022
-
Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Detecting changes in population trends depends on the accuracy of estimated mean population growth rates and thus the quality of input data. However, monitoring wildlife populations poses economic and logistic challenges especially in complex and remote habitats. Declines in wildlife populations can remain undetected for years unless effective monitoring techniques are developed, guiding appropriate management actions. We developed an automated survey workflow using unmanned aerial vehicles (drones) to quantify the number and size of individual animals, using the well-studied Scandinavian harbour seal (Phoca vitulina) as a model species. We compared ground-based counts using telescopes with manual flights, using a zoom photo/video, and pre-programmed flights producing orthomosaic photo maps. We used machine learning to identify and count both pups and older seals and we present a new method for measuring body size automatically. We evaluate the population’s reproductive success using drone data, historical counts and predictions from a Leslie matrix population model. The most accurate and time-efficient results were achieved by performing pre-programmed flights where individual seals are identified by machine learning and their body sizes are measured automatically. The accuracy of the machine learning detector was 95–97% and the classification error was 4.6 ± 2.9 for pups and 3.1 ± 2.1 for older seals during good light conditions. There was a clear distinction between the body sizes of pups and older seals during breeding time. We estimated 320 pups in the breeding season 2021 with the drone, which is well beyond the expected number, based on historical data on pup production. The new high quality data from the drone survey confirms earlier indications of a deteriorating reproductive rate in this important harbour seal colony. We show that aerial drones and machine learning are powerful tools for monitoring wildlife in inaccessible areas which can be used to assess annual recruitment and seasonal variations in body condition.
|
|
| 37. |
- Jagers, Peter, 1941, et al.
(författare)
-
Viability of small populations experiencing recurring catastrophes
- 2009
-
Ingår i: Mathematical Population Studies. - 0889-8480. ; 16:3, s. 177-198
-
Tidskriftsartikel (refereegranskat)abstract
- Some small populations are characterized by periods of exponential growth, interrupted by sudden declines in population number. These declines may be linked to the population size itself, for example through overexploitation of local resources. We estimate the longterm population extinction risk and the time to extinction for thistype of repeatedly collapsing populations. Our method is based on general branching processes, allowing realistic modelling of reproduction patterns, litter (or brood or clutch) sizes, and life span distributions, as long as individuals reproduce freely and density effects are absent. But as the population grows, two extrinsic factors enter: habitat carrying capacity and severity of decline after hitting the carrying capacity. The reproductive behaviour of individuals during periods when the population is not experiencing any density effects also has a fundamental impact on the development. In particular, this concerns the population's potentialfor recovery, as mirrored by the intrinsic rate of increase as well as the extinction probability of separate family lines of unhampered populations. Thus, the details of life history which shape demographic stochasticity and determine both rate of increase and extinction probability of freely growing populations,can have a strong effect on overall population extinction risk. We are interested in consequences for evolution of life history strategies inthis type of systems. We compare time to extinction of asingle large system (high carrying capacity) with that of a population distributed over several small patches, andfind that for non-migrating systems a single large ispreferable to several small habitats.
|
|
| 38. |
- Jonasson, Johan, 1966, et al.
(författare)
-
A Unifying Framework for Estimating Generation Time in Age-Structured Populations: Implications for Phylogenetics and Conservation Biology
- 2022
-
Ingår i: American Naturalist. - : University of Chicago Press. - 0003-0147 .- 1537-5323. ; 200:1
-
Tidskriftsartikel (refereegranskat)abstract
- Generation time is a measure of the pace of life and is used to describe processes in population dynamics and evolution. We show that three commonly used mathematical definitions of generation time in age-structured populations can produce different estimates of up to several years for the same set of life history data. We present and prove a mathematical theorem that reveals a general order relation among the definitions. Furthermore, the exact population growth rate at the time of sampling influences estimates of generation time, which calls for attention. For phylogenetic estimates of divergence times between species, included demographic data should be collected when the population growth rate for each species is most common and typical. In conservation biology, demographic data should be collected during phases of population decline in declining species, contrary to common recommendations to use predisturbance data. The results can be used to improve the International Union for Conservation of Nature's recommendation in parameterizing models for evaluating threat categories of threatened species and to avoid underestimating extinction risk.
|
|
| 39. |
- Kauhala, K., et al.
(författare)
-
The effect of prey quality and ice conditions on the nutritional status of Baltic gray seals of different age groups
- 2017
-
Ingår i: Mammal Research. - : Springer Science and Business Media LLC. - 2199-2401 .- 2199-241X. ; 62:4, s. 351-362
-
Tidskriftsartikel (refereegranskat)abstract
- We analyzed a long-term data set of the body condition of Baltic gray seals (Halichoerus grypus) over time and investigated how average subcutaneous blubber thickness of different age groups of seals corresponds to environmental factors. Blubber thickness of pups declined until 2010. The decreasing weight of 5-6-year-old herring (Clupea harengus), the main prey fish for Baltic gray seals, explained well the decline. In the Gulf of Finland, the blubber thickness of pups declined also in recent years (2011-2015) with declining number of days with permanent ice cover. In other regions, the blubber thickness of pups increased during recent years with increasing weight of herring. The blubber thickness of sub-adults in Baltic Proper and that of hunted adult females in the Bothnian Bay also increased during recent years, and the weight of age 6+ or 7-year-old herring best explained the increase. The blubber thickness of all age groups of seals was thinnest in the Bothnian Bay where also herring weight was lowest. There was a negative correlation between blubber thickness of seals and herring catch size (an index of herring abundance) suggesting that herring quality, not the quantity, is important for the nutritional status of Baltic gray seals. Nutritional status of gray seals may thus reveal changes in the marine food web which affect herring quality. Marine food web, in turn, may be affected, e.g., by climate change. The warming climate also has an impact on ice cover and thus body condition of seal pups.
|
|
| 40. |
- Khairy, M., et al.
(författare)
-
Bioaccumulation of PCBs, OCPs and PBDEs in Marine Mammals From West Antarctica
- 2021
-
Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- To understand the bioaccumulation and food web dynamics of persistent organic pollutants (POPs) as a function of species, age and sex in Antarctic mammals, blubber samples of 3 killer whales (Type C) and 77 pinnipeds (Weddell, Ross and crabeater seals) were collected from the Southern Ocean, Antarctica. They were analyzed for polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs). sigma DDTs, sigma(29)PCBs and chlordanes (12 - 4,600, 13 - 1,600, and < 1.5 - 1,700 ng/g lipid, respectively) were the most abundant POPs. Killer whales typically displayed several times greater concentrations of POPs compared to seals, except for PBDEs. PCBs and PBDEs were consistently higher in adult crabeater and Weddell seal males, and in adult female Ross seals than in other sex and age groups reflecting an age accumulation and possible influence of segregated diet, foraging areas, and metabolic transformation rates. POPs concentrations significantly correlated with gene transcription of nuclear receptors involved in detoxification of contaminants and immune relevant cell mediators in the crabeater seals, indicating possible immunotoxic and deleterious health effects. This represents one of the largest studies on POPs in Antarctic marine predators and highlights the complexity of POPs bioaccumulation.
|
|
| 41. |
- Kleinhans, David, et al.
(författare)
-
The role of asymmetric dispersal in metapopulations
- 2009
-
Ingår i: Presented at First Swedish meeting on Theory and Mathematics in Biology and Medicine, Uppsala, December 17th and 18th, 2009.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Metapopulations consist of a number of sub-populations connected through the dispersal of migrants. In many theoretical approaches often rather simple dispersal patterns are investigated, while typically complex dispersal patterns are observed in nature. This especially is the case for larvae dispersal in marine environments driven by ocean currents. In a recent work Vuilleumier and Possingham investigate the role of symmetry in dispersal patterns and draw the conclusion, that asymmetric dispersal has a distinct negative impact on population viability. Our results based on artificial dispersal patterns, however, suggest that symmetry actually only could have a vanishing impact. The simulation results are in good agreement with tests on realistic dispersal patterns of mussel larvae in the Baltic Sea. We demonstrate the importance of artificially generated dispersal patterns for the disentanglement of the complexity intrinsic to natural systems. Although many aspects of larvae dispersal might not yet have been understood we can draw the conclusion, that asymmetry might not be as severe as expected by Vuilleumier and Possingham. That is of course good news for many systems of biological relevance.
|
|
| 42. |
- Kleinhans, David, 1979, et al.
(författare)
-
The role of asymmetric dispersal in metapopulations
- 2009
-
Ingår i: Presented at First Swedish meeting on Theory and Mathematics in Biology and Medicine, Uppsala, December 17th and 18th, 2009.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Metapopulations consist of a number of sub-populations connectedthrough the dispersal of migrants. In many theoretical approachesoften rather simple dispersal patterns are investigated, whiletypically complex dispersal patterns are observed in nature. Thisespecially is the case for larvae dispersal in marine environmentsdriven by ocean currents.In a recent work Vuilleumier and Possingham investigate the role ofsymmetry in dispersal patterns and draw the conclusion, thatasymmetric dispersal has a distinct negative impact on populationviability. Our results based on artificial dispersal patterns,however, suggest that symmetry actually only could have a vanishingimpact. The simulation results are in good agreement with tests onrealistic dispersal patterns of mussel larvae in the Baltic Sea.We demonstrate the importance of artificially generated dispersalpatterns for the disentanglement of the complexity intrinsic tonatural systems. Although many aspects of larvae dispersal might notyet have been understood we can draw the conclusion, that asymmetrymight not be as severe as expected by Vuilleumier and Possingham. Thatis of course good news for many systems of biological relevance.
|
|
| 43. |
- Lehnert, K., et al.
(författare)
-
Antarctic seals: Molecular biomarkers as indicators for pollutant exposure, health effects and diet
- 2017
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697. ; 599, s. 1693-1704
-
Tidskriftsartikel (refereegranskat)abstract
- Weddell (Leptonychotes weddellii), Ross (Ommatophoca rossii) and crabeater seals (Lobodon carcinophaga) are phocid seals with a circumpolar distribution around Antarctica. As long-lived and large top predators, they bioaccumulate contaminants and are considered as sentinels of ecosystem health. Antarctic seals are increasingly exposed to climate change, pollution, shipping and fisheries. To reveal and understand possible anthropogenic impacts on their immune and health status, this study investigates sensitive biomarkers of the xenobiotic metabolism and immune system in relation to mercury (Hg) burden. Gene-transcription studies using minimally invasive blood samples are useful to monitor physiological processes in wildlife that can be related to different stressors. Blood samples of 72 wild-caught seals (Weddell n = 33; Ross n = 12; crabeater n = 27) in the Amundsen and Ross Seas in 2008-2011 were investigated. Copy numbers per mu l mRNA transcription of xenobiotic biomarkers (aryl hydrocarbon receptor (AHR)), aryl hydrocarbon receptor nuclear translocator (ARNT) and peroxisome proliferator-activated receptor (PPAR alpha) and immune relevant cell mediators (cytokines interleukin-2 (IL-2), interleukin-10 (IL-10) and heat-shock-protein 70 (HSP70)) were measured using reference genes Tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, zeta polypeptide (YWHAZ) and ribosomal protein L4 (RPL4) by real time RT-qPCR. Hg concentration was analysed in fur. Hg concentration increased with body weight and standard length in all species. Crabeater seals showed a lower Hg concentration than Ross and Weddell seals. Species-specific differences in gene-transcription were found between all species with highest levels of AHR, ARNT and PPARa in crabeater seals. Ross seals showed highest IL-10 and HSP70 transcription, while HSP70 was exceptionally low in crabeater seals. Between Hg and HSP70 a clear negative relationship was found in all species. The species-specific, age and sex-dependent gene-transcription probably reflect dietary habits, pollutant exposure and immune status. (C) 2017 Published by Elsevier B.V.
|
|
| 44. |
- Leidenberger, Sonja, et al.
(författare)
-
Ecology and Distribution of the Isopod Genus Idotea in the Baltic Sea: Key Species in a Changing Environment
- 2012
-
Ingår i: Journal of Crustacean Biology. - : Oxford University Press (OUP). - 0278-0372 .- 1937-240X. ; 32:3, s. 359-381
-
Tidskriftsartikel (refereegranskat)abstract
- Marine isopods of the genus Idotea [I. balthica (Pallas, 1772), I. chelipes (Pallas, 1766), and I. granulosa Rathke, 1843] are common meso-grazers that enter deep into the Baltic Sea and here appear to live at their physiological limit, determined by salinity and temperature tolerance. We review available data on distribution and community ecology to assess the functional role of Idotea in the Baltic Sea and how global change may affect essential ecological interactions. Data from the last 150 years suggest an on-going shift southward for I. chelipes and I. granulosa that may be caused by a changing climate. Several studies report local extinctions and mass abundances, which may be caused by a changing food web from over-fishing and eutrophication. The three species of Idotea have clear habitat segregation in the Baltic Sea, where salinity, temperature and vegetation are the main dimensions. Idotea spp. have a central role as grazers and in communities dominated by the perennial macrophytes Fucus spp. and Zostera marina and attain impressive feeding rates on a range of epiphytes/filamentous algae (top-down effect). Idotea can have both a direct negative grazing effect on macrophytes but also an indirect positive effect by removing epiphytes. The relative role of nutritional value and chemical defence for food preference is yet unclear for Idotea. Baltic idoteids are also important prey for several fish (bottom-up effect) and fish predation may have increased following overfishing of piscivorous fish. It is concluded that Idotea is a key taxon in the Baltic Sea food web, where guilds often contain few dominant species. Changes in population dynamics of Idotea, as a function of human generated global change, may have large-scale consequences for ecosystem functions in a future Baltic Sea, e.g. the extent of vegetation cover in the coastal zone.
|
|
| 45. |
|
|
| 46. |
- Mauritsson, Karl, et al.
(författare)
-
Maternal Transfer and Long-Term Population Effects of PCBs in Baltic Grey Seals Using a New Toxicokinetic-Toxicodynamic Population Model
- 2022
-
Ingår i: Archives of Environmental Contamination and Toxicology. - : Springer Science and Business Media LLC. - 0090-4341 .- 1432-0703. ; 83:4, s. 376-394
-
Tidskriftsartikel (refereegranskat)abstract
- Empirical evidence has shown that historical exposure of polychlorinated biphenyls (PCBs) to Baltic grey seals not only severely affected individual fitness, but also population growth rates and most likely caused the retarded recovery rate of the depleted population for decades. We constructed a new model which we term a toxicokinetic-toxicodynamic (TKTD) population model to quantify these effects. The toxicokinetic sub-model describes in detail the bioaccumulation, elimination and vertical transfer from mother to offspring of PCBs and is linked to a toxicodynamic model for estimation of PCB-related damage, hazard and stress impacts on fertility and survival rates. Both sub-models were linked to a Leslie matrix population model to calculate changes in population growth rate and age structure, given different rates of PCB exposure. Toxicodynamic model parameters related to reproductive organ lesions were calibrated using published historical data on observed pregnancy rates in Baltic grey seal females. Compared to empirical data, the TKTD population model described well the age-specific bioaccumulation pattern of PCBs in Baltic grey seals, and thus, the toxicokinetic parameters, deduced from the literature, are believed to be reliable. The model also captured well the general effects of PCBs on historical population growth rates. The model showed that reduced fertility due to increased PCB exposure causes decreased vertical transfer from mother to offspring and in turn increased biomagnification in non-breeding females. The developed TKTD model can be used to perform population viability analyses of Baltic grey seals with multiple stressors, also including by-catches and different hunting regimes. The model can also be extended to other marine mammals and other contaminants by adjustments of model parameters and thus provides a test bed in silico for new substances.
|
|
| 47. |
- McNamara, J. M., et al.
(författare)
-
Measurement error and estimates of population extinction risk
- 2004
-
Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 7:1, s. 16-20
-
Tidskriftsartikel (refereegranskat)abstract
- It is common to estimate the extinction probability for a vulnerable population using methods that are based on the mean and variance of the long-term population growth rate. The numerical values of these two parameters are estimated from time series of population censuses. However, the proportion of a population that is registered at each census is typically not constant but will vary among years because of stochastic factors such as weather conditions at the time of sampling. Here, we analyse how such sampling errors influence estimates of extinction risk and find sampling errors to produce two opposite effects. Measurement errors lead to an exaggerated overall variance, but also introduce negative autocorrelations in the time series (which means that estimates of annual growth rates tend to alternate in size). If time series data are treated properly these two effects exactly counter balance. We advocate routinely incorporating a measure of among year correlations in estimating population extinction risk.
|
|
| 48. |
- Pertold, Cino, et al.
(författare)
-
Prevalence of skull pathologies in European harbor seals (Phoca vitulina) during 1981–2014
- 2018
-
Ingår i: Mammal Research. - : Springer Science and Business Media LLC. - 2199-2401 .- 2199-241X. ; 63:1, s. 55-63
-
Tidskriftsartikel (refereegranskat)abstract
- Harbor seals (Phoca vitulina) inhabit the seas surrounding Denmark and are an important top predator in the marine food chain. This trophic position exposes them to environmental contaminants with disease epi- demics and hunting being additional threats to this popu- lation. It is therefore important to study how environmen- tal pollution at the current order of magnitude affects the health of the population. Earlier studies have shown that occurrence of periodontitis could be linked to the amount of pollution the seals were subjected to. In order to inves- tigate this further, 380 skulls and 141 mandibles of harbor seals (Phoca vitulina) from the Wadden Sea, the Limfjord, and Kattegat collected during the period 1970–2014 were examined. The skulls were examined for pathological le- sions. The Hounsfield Units (HU) which are correlated to the bone mineral density (BMD) were measured in a sub- sample (n= 34) using CT scans. The macroscopic examination revealed (with the exception of the Swedish part of Kattegat) a significant increase of pathological lesions over the study period of 1981–2014. The exami- nation of HU showed that median HU measured at mul- tiple sites was highest in the healthy skulls compared to the skulls with one or more of the lesions. A discriminant analysis allowed high discriminatory capacity to separate healthy skulls from the skulls with pathologies, simply by the utilization of the HU data. Former studies of BMD in marine mammals have shown that exposure to environ- mental chemicals alter BMD and cause periodontitis. The present study, based on temporal and spatial trends in BMD, confirms the results of previous studies Prevalence of skull pathologies in European harbor seals (Phoca vitulina) during 1981–2014 (PDF Download Available). Available from: https://www.researchgate.net/publication/320586176_Prevalence_of_skull_pathologies_in_European_harbor_seals_Phoca_vitulina_during_1981-2014 [accessed Dec 15 2017].
|
|
| 49. |
- Roy, M., et al.
(författare)
-
Generalizing Levins metapopulation model in explicit space: Models of intermediate complexity
- 2008
-
Ingår i: Journal of Theoretical Biology. - : Elsevier BV. - 0022-5193. ; 255:1, s. 152-161
-
Tidskriftsartikel (refereegranskat)abstract
- A recent study [Harding and McNamara, 2002. A unifying framework for metapopulation dynamics. Am. Nat. 160, 173-185] presented a unifying framework for the classic Levins metapopulation model by incorporating several realistic biological processes, such as the Allee effect, the Rescue effect and the Anti-rescue effect, via appropriate modifications of the two basic functions of colonization and extinction rates. Here we embed these model extensions on a spatially explicit framework. We consider population dynamics on a regular grid, each site of which represents a patch that is either Occupied or empty, and with spatial coupling by neighborhood dispersal. While broad qualitative similarities exist between the spatially explicit models and their spatially implicit (mean-field) counterparts, there are also important differences that result from the details of local Processes. Because of localized dispersal, spatial correlation develops among the dynamics of neighboring populations that decays with distance between patches. The extent of this correlation at equilibrium differs among the metapopulation types, depending on which processes prevail in the colonization and extinction dynamics. These differences among dynamical processes become manifest in the spatial pattern and distribution of "clusters" of occupied patches. Moreover, metapopulation dynamics along a smooth gradient of habitat availability show significant differences in the spatial pattern at the range limit. The relevance of these results to the dynamics of disease spread in metapopulations is discussed. (C) 2008 Elsevier Ltd. All rights reserved.
|
|
| 50. |
- Saremi, Sadaf, et al.
(författare)
-
Bio accumulation of radioactive caesium in marine mammals in the Baltic Sea – Reconstruction of a historical time series
- 2018
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697. ; 631-632, s. 7-12
-
Tidskriftsartikel (refereegranskat)abstract
- Radionuclides from the Chernobyl accident in 1986 still circulate in the Baltic marine ecosystem and activity levels in water, sediments and fish species such as herring and perch are monitored annually. However, the activity levels of radionuclides in marine mammals have only been sporadically reported. Tissue samples from a museum collection were analysed in two species of seals, and the trends over time in activity level of radioactive caesium (Cs-137) after the Chernobyl accident were reconstructed. We also performed a literature review summarizing activity levels in marine mammals world-wide. We found activity concentrations of Cs-137 in Baltic ringed seals and grey seals to be elevated also in the most recent samples, and during the entire study period measurements ranged between 19 and 248Bq/kg wet weight. A declining trend in time over the last 30years follow the general trend of decline in activity levels in other Baltic biota. Accumulation was found to be species specific in the two seal species studied, with 9 times higher activity concentration in grey seals compared to herring, and 3.5 times higher in ringed seals compared to herring. We discuss potential paths and rates of bioaccumulation of radioactive caesium in the Baltic Sea including species specific prey choice of the two seal species and estimate life time exposure. The study contributes one important piece of information to predictive models in risk assessments for nuclear accidents.
|
|
