Author: isabel

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On the whereabouts of high arctic lemmings in winter

Lemmings are key species in the arctic tundra. Yet, their whereabouts during the long winter is highly understudied. Luckily, we can use lemming winter nests as an indicator of habitat use by lemmings under the snow. Here we analyzed location data for more than 4200 collared lemming winter nests, collected each year since 1996 at Zackenberg in NE Greenland as part of Greenland Ecosystem Monitoring. We found that lemming select habitats where snow accumulates, but also showed that the strength of the habitat selection varies with lemming density. Moreover, by examining the winter nests for signs of breeding and predation by stoats, we found the larger lemming nests were found in the most preferred habitat (Salix snow beds), and that these were more likely to used for breeding, but also more likely to be depredated than smaller nests. These patterns suggest that the observed density-dependent habitat selection appeared to equalize fitness across the various habitat types.

You can read the full article here.

Reference: Schmidt, N.M., van Beest, F.M., Dupuch, A. et al. Long-term patterns in winter habitat selection, breeding and predation in a density-fluctuating, high Arctic lemming population. Oecologia (2021). https://doi.org/10.1007/s00442-021-04882-2

Text written by Niels Martin Schmidt.

Picture: Collared lemming (photo credit: Lars Holst Hansen)

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PhD position in terrestrial ecology at the University of Iceland

Deadline for applications: March 8, 2021

The Faculty of Life- and Environmental Sciences at the University of Iceland is seeking a motivated candidate for a three-year PhD position for the project “Trapped in a degraded state? Tundra ecosystem responses to grazing cessation” (TRAPP). The project is funded by the Icelandic Research Fund and will investigate processes that prevent transition of degraded ecosystems to healthier states. Iceland provides good settings for the study because centuries of heavy grazing by livestock have driven extensive tundra rangelands into degraded states. The PhD student will focus on the role of different plant functional types in retarding the recovery process by using both large scale surveys and field experiments.

Research team and collaboration – The PhD student will be a part of an international research team, led by Ingibjörg Svala Jónsdóttir and including Isabel C. Barrio (Agricultural University of Iceland), Bryndís Marteinsdóttir, (Soil Conservation Service of Iceland), Kari Anne Bråthen (UiT-The Arctic University of Norway, Tromsø) and David Hik (Simon Fraser University, Vancouver, Canada). In addition, five other national and international collaborators will be involved in specific research tasks.

Education, desired skills and work experience

We are seeking a highly motivated candidate with outstanding track-record and:

  • A masters degree in Biology, Ecology or related fields
  • Strong background knowledge in botany and ecology
  • Good skills in statistical analysis (the R software) is desirable
  • Experience of microbial research and application of molecular methods is desirable
  • Experience of laboratory work and fieldwork under demanding conditions in the tundra is desirable

Other requirements:

  • Excellent English, both written and spoken
  • Good planning and organization skills
  • Good communication and teamwork skills
  • The ability to work independently

For further information, please contact Ingibjörg Svala Jónsdóttir at isj@hi.is

The Application process:

Deadline for application is 8th of March 2021. The student is expected to start as soon as possible, or no later than April 2021

Applications should be submitted electronically by March 8th 2021 at https://english.hi.is/vacancies (choose the relevant option and register – the option will show up after February 15). Attach the following information to your application:

  • A short letter (max. 2 pages) of motivation where the candidate also provides her/his future vision and why pursuing a PhD degree
  • CV (curriculum vitae) including education, research and work experience.
  • Certificates of education (BS and MSc degree) and course transcripts with grades.
  • Names and full contact information for two professionals referees (including their relationship to the applicant).
  • Overview of publications (if any).
  • (Optional) Applicants are also invited to send PDF of MS thesis (in any language) and any other relevant publications if available (max. 5 documents).

Further information

All applications will be answered and applicants will be informed about the appointment when a decision has been made. Applications are valid in the system for 6 months after the application deadline. After the hiring process is completed the applicant must apply formally for PhD studies at the University of Iceland.

The University of Iceland is committed to diversity and we encourage all qualified candidates to apply. Appointments to positions at the University of Iceland are made in consideration of the Equal Rights Policy of the University of Iceland. http://www.hi.is/haskolinn/jafnrettisaaetlun#markmid2

The University of Iceland is a growing community of knowledge and is a very dynamic and interesting workplace. Our values are academic freedom, professionalism and equality. The University strives to provide flexibility and encourages participation in the progression of the studies and research in all fields within the realm of the University.

The School of Engineering and Natural Sciences employs around 400 people involved with teaching and research. The School offers an international working environment, with the number of international employees and students increasing each year. Currently about quarter of all employees and graduate students are international. The school has 2000 students, thereof around 180 PhD students and 340 MS students. The School of Engineering and Natural Sciences is proud of its’ diversity and reform-minded environment where knowledge acquisition and sharing is paramount.

The Biomedical Center BMC (lifvisindi.hi.is) is a co-operation between research groups in life-sciences in Iceland.  Through the center the student will have access to well-equipped core facilities and a collaborative cross-disciplinary research environment.

If you are interested in this project, you may also be interested in another related PhD position at the Agricultural University of Iceland.

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Postdoctoral position in Tromsø within the CHARTER project

Two-year postdoctoral position at UiT The Arctic University of Norway and The Norwegian Institute for Nature Research (NINA).

We are looking for a postdoctoral fellow to join the EU-project “Drivers and Feedbacks of Changes in Arctic Terrestrial Biodiversity (CHARTER)”. The project is an ambitious effort to advance the adaptive capacity of Arctic communities to climatic and biodiversity changes through state-of-the-art synthesis based on thorough data collection, analysis and modelling of Arctic change with major socio-economic implications and feedbacks. CHARTER involves 21 research institutions across nine countries and is led by the Arctic Centre at the University of Lapland.

In CHARTER, the postdoc will primarily work with topics on Arctic biodiversity and transitions in land cover and the cryosphere related to direct and indirect impacts of major drivers of change over decadal time scales using mainly existing datasets collected on the ground and through remote sensing (mainly work packages 1 and 2 in CHARTER). Research topics will include:

  • herbivory, and relationships between different herbivores in tundra ecosystems
  • predator community composition/changes
  • climatic and environmental changes driving rapid vegetation transitions with impacts on local communities and nature-based industries

CHARTER has a strong focus on involving various stakeholders, including reindeer herders and managers, and in communicating with public authorities on multiple levels. The postdoc will be involved in communication with stakeholders and authorities.

You can find more information and the link to the application portal here.

Deadline for applications is March 3, 2021. For more information please contact Dorothee Ehrich (dorothee.ehrich@uit.no), Hans Tømmervik (hans.tommervik@nina.no) or Jarle Bjerke (jarle.bjerke@nina.no).

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PhD position at the Agricultural University of Iceland

Deadline for applications: March 5, 2021

We are looking for a motivated PhD student to join the project “Herbivores in the tundra: linking diversity and function (TUNDRAsalad)” funded by the Icelandic Research Fund.

TUNDRAsalad will explore the role of herbivore diversity in tundra ecosystems, and how different assemblages of herbivores influence ecosystem functions in high latitude ecosystems. The PhD project will focus on Iceland, to understand the impacts of herbivore diversity and guide sustainable grazing management at a regional scale. Iceland represents a unique situation with no native large mammalian herbivores but extensive grazing by domestic and introduced mammals (sheep and reindeer), ptarmigan and increasing populations of migratory avian herbivores (geese and swans). Current knowledge of species abundance and distribution will be used to estimate herbivore pressure and diversity across Iceland and target field sites in the grazing commons above the alpine treeline. The PhD project will involve mapping the distribution of herbivores in Iceland and conducting fieldwork to measure ecosystem function across Iceland, as well as modelling the potential impacts of changes in herbivore assemblages in Iceland over time.

The PhD project will focus on Iceland, to understand the impacts of herbivore diversity and guide sustainable grazing management at a regional scale.

The PhD student will be based at the Reykjavík campus of the Agricultural University of Iceland, and will be co-supervised by Isabel C Barrio (Agricultural University of Iceland), James Speed (Norwegian University of Science and Technology) and Noémie Boulanger-Lapointe (University of Iceland).

The deadline for applications is March 5, 2021 and the position will start as soon as possible after April 1, 2021. The project has a duration of three years.

Applications are welcome from candidates with a MSc degree in ecology, environmental sciences or related fields. Applicants should ideally have experience in conducting fieldwork in remote areas and be able to work as part of a team and independently. Knowledge on the use of Geographic Information Systems (GIS), the statistical software R and a driving license are desirable skills.

In your application you should include:

  • Cover letter that explains how your research interests and experience align with the position
  • CV or resume, including your overall grade and relevant experience
  • List of two professional references and their contact information

Please send your application and any questions to Isabel C Barrio (isabel@lbhi.is). For more details see the ad on the website of the Agricultural University of Iceland.

If you are interested in this project, you may also be interested in another related PhD position at the University of Iceland.

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Environmental change reduces body condition, but not population growth, in a high‐arctic herbivore

The high Arctic is changing rapidly: climate change means advancing springs, and more treacherous winters, with more frequent extreme weather events. On top of this, barnacle geese breeding in the Arctic have been on a diet. So many geese are now migrating to northern breeding grounds that in some places there’s less food to go around. The good news is that it doesn’t seem to restrict their population growth — yet.

This study of individuals’ physical condition, over almost 30 years, showed a 10% decline in average body condition. Especially for herbivores, reduced condition should lead to reduce reproduction and survival. Surprisingly, however, this decline didn’t translate into noticeable effects on population numbers. This is because it’s overridden by other important environmental effects, such as positive impacts of earlier springs and negative effects of Arctic foxes on reproduction. Nevertheless, there is obviously a limit to how skinny the geese can be, if their summer habitat continues to degrade, so it’s likely to restrict population growth at some point in the future.

Fieldwork in Ny‐Ålesund, Svalbard where Barnacle geese were captured to measure body mass. (Photo credit: Christiane Hubner)

You can find the full paper here.

Reference: Layton‐Matthews, K., Grøtan, V., Hansen, B.B., Loonen, M.J., Fuglei, E. and Childs, D.Z., 2020. Environmental change reduces body condition, but not population growth, in a high‐arctic herbivore. Ecology Letters. doi: 10.1111/ele.13634

Link to full article write up: https://norwegianscitechnews.com/2020/12/skinnier-but-resilient-geese-thriving-in-the-high-arctic/

Text: Kate Layton-Matthews, Norwegian Institute for Nature Research

Photograph: Svalbard barnacle geese (Branta leucopsis) (photo credit Jasper Doest Photography)

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Two Arctic Postdoctoral Researcher positions at the University of Eastern Finland

The project Land use as a modulator of land cover transitions and the ecosystem–atmosphere carbon balance (LANDMOD) is associated with the Digital Geosciences Research Group at the University of Eastern Finland (Joensuu campus). The aim of the project is to unravel the impacts of land use on land cover changes and their consequences for the climate. We particularly look at reindeer management strategies as the type of land-use and focus on depicting land cover differences on wetlands. Our main objectives are 1) to contribute understanding of the rates, magnitudes and mechanisms of land cover changes under different reindeer management strategies and 2) to quantify how the differences in land cover reflect on the release and uptake of CO2 in a landscape level using Eddy Covariance technology. Besides estimating the impact of land use today, we will also estimate the influence of past land use on the cumulative carbon balance. With these approaches, the project will contribute understanding on how and why the rates and magnitudes of land cover transitions vary at high-latitudes in northern Fennoscandia, and how these feedback to the atmosphere.

In the project, we open two two-year postdoctoral researcher positions: a postdoctoral researcher position in Remote Sensing and a postdoctoral researcher position in Ecosystem-Atmosphere Biogeochemistry. Both postdoctoral researchers will take part in an international research team and collaborate with Timo Kumpula (University of Eastern Finland), Henni Ylänne (University of Eastern Finland / Lund University), Natascha Kljun (Lund University), Oliver Sonnentag (Université de Montréal), Christina Biasi (University of Eastern Finland) and Narasinha Shurpali (Natural Resources Institute Finland).

Deadline for applications is February 25, 2021.

More info on the positions can be found in the attachment or on the UEF application portal:

For further information, please contact: Timo Kumpula (timo.kumpula@uef.fi) or Henni Ylänne (henni.ylanne@cec.lu.se)

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Funding from UniOulu Arctic Researchers’ Network Call

Congratulations to Maria Väisänen who received funding for the project Impacts of grazers on litter decay rates across northern hemisphere revealed using peer-sourced research network and standardized protocols from the UniOulu Arctic Researchers’ Network Call for proposals for Early stage researchers.

The funding will allow purchasing teabags and temperature loggers to address the question: how do herbivory induced differences in vegetation cascade down to litter decay rates? Some pilot sites in Iceland, Norway and Finland with existing grazing exclosures will be used in summer 2021, with the aim of testing the field protocols and expanding the network of sites in coming years.

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Extensive grazing reduces plant and soil C stocks in the highlands of central Argentina

In this article we describe for the first time the amount of C stored in the plant and soil compartments of extensively grazed highland grasslands of central Argentina under different grazing pressure, to understand their contribution to regional carbon storage.

We quantified C stocks of standing plant, litter, and roots biomass, and soil in three coexisting grassland types associated with different livestock use and analysed how those stocks vary across grassland types. Our main results showed that these mountain grasslands represent an important regional C reservoir, with total C stocks (plant plus soil) ranging from 110 to 472 Mg C ha−1, with more than 95% of C being stored in soils. Differences in soil C stocks up to 30 cm depth were not associated with grassland types. However, in patches associated with higher livestock use, belowground plant C increased, whereas aboveground plant C was reduced.

Our study shows that highland grasslands of central Argentina maintain huge soil C reservoirs. Livestock use could reduce surface C stocks by affecting the plant biomass compartments, which could have a long-term effect on soil C stocks, with direct implications for mountain grasslands management and conservation in the context of climate change mitigation.

You can find the full article here, or ask Georgina Conti for a copy 🙂

Reference: Vaieretti, M.V., Conti, G., Poca, M., Kowaljow, E., Gorné, L., Bertone, G., Cingolani, A.M. and Pérez‐Harguindeguy, N. (2021) Plant and soil carbon stocks in grassland patches maintained by extensive grazing in the highlands of central Argentina. Austral Ecology.
https://doi.org/10.1111/aec.12992

Picture: Extensive grazing in the central highlands of Argentina (photo: Georgina Conti, Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina)

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Novel trophic interactions under climate change promote alpine plant coexistence

Elevational shifts in the distribution of species can have large consequences to high-elevation ecosystem. More so, when we are talking about herbivores.

In a field experiment, Patrice Descombes and collaborators translocated various species of grasshoppers from medium elevations (1,400 m a.s.l.) to three alpine grassland sites at 1,800, 2,070 and 2,270 m a.s.l. in the Anzeindaz region in the Vaud Alps. They measured how the biomass, structure and composition of the alpine plant communities changed under the influence of the herbivorous insects. They also investigated whether some plant species were more susceptible to herbivory, for instance plants with tougher leaves, or those containing more silica or other constituents such as phenols or tannins.

Roesel’s bush-​cricket is one of the many grasshoppers that might migrate to higher elevations once the climate in lower elevations has become unsuitable (photograph: Christian Roesti)

The grasshoppers’ feeding behaviour had a clear influence on the vegetation structure and composition of the alpine flora. Alpine communities display clear structure in the organisation of the canopy, with plants with tough leaves at the top, and more shade-​tolerant plants with softer leaves at the bottom. But this natural organisation was disturbed, because the translocated grasshoppers preferred to feed on taller and tougher alpine plants, that were more similar to their lower-​elevation food plants. As a result, the insects reduced the biomass of dominant alpine plants, favouring the growth of small-​statured plants. The overall plant diversity thus increased in the short term.

Global warming can disrupt the ecological balance of biotic communities because mobile animals, including many herbivorous insects, can expand their habitat to higher elevations more rapidly than sedentary plants. Herbivorous insects from lower altitudes could therefore have an easy time in alpine habitats with resident plants that are insufficiently prepared to defend themselves against those new herbivores. This could change the current structure and functioning of alpine plant communities as a whole. Climate change would thus have an indirect impact on ecosystems, in addition to the direct consequences of rising temperatures.

Their study has been published in Science. You can find the full article here.

Reference: Descombes, P., Pitteloud, C., Glauser, G., Defossez, E., Kergunteuil, A., Allard, P.M., Rasmann, S. and Pellissier, L. (2020) Novel trophic interactions under climate change promote alpine plant coexistence. Science, 370(6523):1469-1473.

Picture: Research site at 1,800 m in the Chablais region. In the background: Vallon de Nant and the Grand Muveran (photo: P. Descombes)

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DISENTANGLE: Disentangling the impacts of herbivory and climate on ecological dynamics

The project led by James Speed, started in 2017 and investigated the interactive effects of herbivory and climate on northern ecosystems. The DISENTANGLE project was hosted by the NTNU University Museum, Norwegian University of Science and Technology. Partners included Isabel Barrio (Agricultural University of Iceland), Alison Hester (James Hutton Institute, Scotland), John-Arvid Grytnes (University of Bergen), Jean-Pierre Tremblay (Université Laval) and Gunnar Austrheim and Mike Martin (NTNU). 

There are three components to the project, the first used dendroecology to tease apart the effects of herbivory and climate on woody plant growth in boreal and tundra ecosystems, and long-term plant community data to investigate the herbivore and climate impacts on vegetation change. Katariina Vuorinen, a PhD student at the NTNU University Museum led this work (Vuorinen et al. 2022). The second aspect of the project investigated how herbivores affect the distribution of plant species. The third section of the project mapped out herbivore communities across the boreal and tundra biomes (Speed et al. 2021). 

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