Category: news

The Tundra Exclosure Network (TExNet) is a coordinated research initiative that aims at understanding the role of herbivore diversity on the functioning of tundra ecosystems. To do this, TExNet has established a network of experimental sites across the tundra, where herbivore diversity is manipulated using size selective exclosures that allow isolating the effects of different herbivores. Setting up an experimental site requires an initial investment and a commitment of at least five years, which can limit the number of participating sites. To expand the geographical spread of the study, an observational protocol was proposed, that required a single visit to the sites, while still collecting data comparable to data collected in the first year of the experiment.

During 2022-2024 data has been collected at six TExNET experimental sites and at 21 additional sites using the observational protocol. Last May 14-19, 2025, part of the TExNet team got together in Nuuk to compile and start analysing the first dataset collected across TExNet sites. The workshop was hosted by the Greenland Institute of Natural Resources. The workshop took place in Nuuk for the first two days at the facilities of GINR, while the last three days part of the team went on a writing retreat to Kapisillit.

During the workshop, the team compiled and curated the database, which is now almost ready for analyses. The different possibilities for analyses were discussed, as well as the opportunities for future data collection and collaboration across the network.  

Funding to organize this workshop was provided by the 2024 UArctic Project Call for Networking Activities on UArctic Research and Education, for the project: “Implications of changes in tundra herbivore diversity -West Greenland in a multiscale circumpolar experiment” led by Mathilde Le Moullec. This project will also help set up two TExNet experimental sites in West Greenland. Support for early career researchers to travel to the workshop was provided by the Nordic Borealization Network (NordBorN) funded by NordForsk (project nr. 164079).

You can read more about the workshop in the TExNet workshop report.

Research networks, including coordinated distributed experiments, have become a key way to conduct ecological research, yet we have limited understanding of their drivers of success. Such networks are founded on the participation of persons like you who implement research methods in a coordinated way.

Some colleagues are asking researchers involved in collaborative research networks to answer a survey to understand the motivations, perceptions and satisfaction of participants in such initiatives. They are gathering information across 53 ecological networks, and have asked HN members to participate. Deadline for completing their survey is June 8!

As a HN member, you should have received an email with the link to the survey and a bit more information about the project. If you have not, please let us know and we can resend it!

Are you, or someone from your group, planning tundra fieldwork for summer 2024? We are too!

Summer 2024 will be the last opportunity to contribute to our observational study on herbivore diversity in tundra. This is a one-time, low-effort sampling campaign across multiple tundra sites, where your effort will contribute to a growing database including 12 sites already. The sampling protocol is simple, and the work can be done by a student or a field assistant.

What we offer:

• Clear field protocols, tested across a range of tundra sites.
• Co-authorship in 1-2 manuscripts assessing the large-scale drivers of herbivore diversity across tundra.
• Opportunity to use the dataset for your own research questions.

What we ask:

• 2-4 person days of field work anywhere in tundra during peak of the growing season. Exact time commitment depends on herbivore abundance at your site.
• Data entry to the database by October 2024.

More information on background, study questions and methods can be found here. If you have any questions or comments, please contact Elina Kaarlejärvi or Isabel Barrio.

We hope you consider joining this study!

After 10 years of contributing to circumpolar research on plant-herbivore interactions, the Herbivory Network is proposing to use a horizon scan to identify research priorities in Arctic herbivory for the coming decade, as a contribution to the ICARP IV (Fourth International Conference on Arctic Research Planning – 2025) process.

For this exciting aim, we are asking for input that will help identify the most important questions to solve the puzzle of herbivory dynamics in the Arctic, by completing this short online survey.

The survey asks you to name one or more priorities for Arctic research in the next decade. These priorities can range from local- to large-scale issues, well-known topics or under-appreciated ones, urgent concerns as well as more distant ones.

Deadline for submissions has been extended until January 28, 2024.

The survey responses will be compiled and organised into thematic categories by a core working group. Subsequently, an in-person workshop is scheduled for March 12, 2024 in Lund, as part of the NSO 2024 conference, to further refine the emerging themes and determine key action points. We anticipate that this collaborative process will be beneficial to ICARP’s objectives while fostering the generation of new knowledge in the field of Arctic herbivory.

---

Photograph: Cambridge Bay (Cléa Frapin)

Herbivores are important drivers of nutrient dynamics in terrestrial ecosystems. By consuming plants and releasing nutrient-rich resources to the soil, herbivores affect nutrient cycling. Near Infrared Spectroscopy (NIRS) represents an effective, low-cost method to assess the nutrient contents of herbivore dung, alternative to more expensive traditional chemical laboratory analyses, but it requires calibration with samples of known chemical content.

Here is where we need your help! We need to collect fresh faecal samples from accurately identified herbivore species. If you are going to the field this summer and you have the chance to collect very fresh faecal matter that you can unequivocally ascribe to a species of herbivore (for example, if you are working with live trapping, culled animals, enclosure experiments, or visiting colonies and nests), we would be very happy to receive samples from you!

The sample collection protocol is very simple (more detailed guidelines are available here). Samples will be shipped to the Agricultural University of Iceland, where all analysis will be conducted. In addition to NIRS calibration curves, the data obtained from these samples will contribute to an open database on nutrient content of herbivore dung. Data contributors will be invited as co-authors of relevant outcomes of this project.

Developing NIRS calibration curves for faecal nutrient content of Arctic herbivores will allow analysing a much larger number of samples needed to address questions at finer temporal and spatial scales, for example, to assess seasonal variation of faecal nutrient contents over the growing season, or to assess herbivore diet quality at different sites. This project will provide a significant methodological advance in the field and will increase our understanding of how herbivores contribute to nutrient cycling in tundra ecosystems.

Relevant documents

• Sample collection protocol
• Data collection template

Zoe Xirocostas and Angela Moles at the University of New South Wales have developed a great app for training researchers to visually estimate leaf damage. We recommend all of you to have a look, and train yourself before you estimate leaf damage in the field 😊

The app presents randomised images of leaves with different amounts of damage. You have to visually estimate damage on those leaves using a slider tool under the image. After submitting your estimate, the correct answer is displayed. Estimates that are within 0-1% of the actual answer are considered accurate. After estimating 10 images, a running average of your estimate accuracy is displayed. Your training will continue until the running average of your last 10 images reaches 98-100% accuracy. Once you have completed your training you will see your progress displayed in a graph.

The app can be found here: ZAX Herbivory Trainer

Stefaniya Kamenova and collaborators are currently trying to elucidate possible methodological biases in the assessment of diet in large herbivores. This is motivated by our recent observation that considerable discrepancies occur in the estimation of dietary proportions in the Svalbard reindeer according to the method used (i.e. DNA metabarcoding, microhistology, stable isotope analysis…). Consequently, we aim at comparing these three methods using samples from the very same individuals, collected at the same time.

While we have a rather good grasp of the DNA metabarcoding and stable isotope methods, microhistology remains a technique requiring very specific training. Therefore, our call is for collaborators trained in the microhistological analysis of herbivore diets, to help us with the screening of 96 rumen and faecal Svalbard reindeer samples.

If you have the expertise and certain interest for this iconic Arctic herbivore, please get in touch with Stefaniya.

---

Photo: Svalbard reindeer (Eeva Soininen)

Interested in burying teabags into your grazing experiment plots?

Do you work in cold ecosystems, tundra or taiga, where you manipulate the intensity of herbivory with exclosures? If the answer is yes, you might be interested in participating in a newly launched research initiative entitled “Impacts of grazers on litter decay rates across northern hemisphere revealed using peer-sourced research network and standardized protocols”.

This research initiative aims at studying the effects of varying herbivory on the initial stages of organic matter decomposition and its underlying drivers across the North. This will be accomplished by the use of green and rooibos tea, following the established teabag index, accompanied by microclimate and vegetation measurements.

This initiative was started by researchers representing the different partner institutes of the UArctic Thematic Network on Herbivory in Spring 2021. The project will provide the protocols and supplies (teabags, microclimate sensors) for collaborating researchers.  

If you are interested to join, please contact Maria Väisänen (maria.vaisanen@oulu.fi). To facilitate communication, please, write “TBI” in the subject field.

You can find the call for collaboration here.

Contact info:
Maria Väisänen
Ecology and genetics research unit, University of Oulu, Finland
maria.vaisanen@oulu.fi

We are looking for enthusiastic collaborators to work on a systematic review on the effects of herbivore diversity in tundra ecosystems! Following the exciting work on the systematic map, we decided to embark on a systematic review. We have drafted a protocol that is currently under review in Environmental Evidence, and are now inviting colleagues to join forces for the next steps.

To join the co-author team, you will need to do about a week of work, including: i) few days on various tasks such as scoring papers for inclusion/exclusion and extracting data from papers, and ii) commenting on the manuscript. We will have a workshop at the Herbivory Network meeting in Tromsø in November to explain the project and the data extraction process, but you can already get involved helping out with some abstract screening.

Short intro to the project

Changes in the diversity of herbivore communities can strongly influence the functioning of northern ecosystems.  Different herbivores have different impacts on ecosystems, due to differences in their diets, behaviour and energy requirements.  The combined effects of different herbivores can in some cases compensate each other but lead to stronger directional changes elsewhere.  However, the diversity of herbivore assemblages has until recently been a largely overlooked dimension of plant-herbivore interactions.  Given the ongoing environmental changes in tundra ecosystems, with increased influx of boreal species and changes in the distribution and abundance of arctic herbivores, a better understanding of the consequences of changes in the diversity of herbivore assemblages is needed.  This systematic review aims to synthetise knowledge about effects of herbivore diversity on different ecosystem processes, functions and properties of tundra ecosystems.

---

Picture: Svalbard reindeer and rock ptarmigan (picture Nicolas Lecomte)