Hunting for bryophytes in the mountains

By Konsta

Part of the Edge Lab’s field campaign last year was to do a bryophyte survey of the plots around Latnjajávri in the Scandinavian mountains in which we also monitor microclimate. The ultimate aim of the project is to be able to relate bryophytes’ traits to their niches. Most work on this aspect of bryophyte functional ecology has been done on categorical traits or with qualitative methods; our focus is on developing and testing hypotheses using quantitative data on both traits and environmental conditions. That work is still ongoing though, so in this post, I will share some of my favourite bryophyte observations instead, along with a bunch of bryophyte factoids!

A stereotypical botanist makes hikes miserable for their friends by stopping constantly to look at interesting species growing in e.g. gutters and other lovely habitats. When in the mountains, it’s important to keep an eye out for poo and rotting animal corpses. If one does, they might spot Tetraplodon pallidus, a coprophilous species that occupies short-lived nutrient-rich habitats such as reindeer droppings and pellets spit out by meat-eating birds. Species in this genus are often quite beautiful with bunches of brightly-colored sporophytes, but looks can be deceiving, in this case literally! Tetraplodon species use devious tactics involving visual and chemical attractants to trick flies into unwilling dispersal agents. Because the species’ habitat is so short-lived it needs an effective strategy for locating new patches of dung or animal remains. The colonization of new habitat patches is greatly aided by the flies that the moss attracts by emitting volatile compounds. I know of no study that has quantified the volatiles emitted by just this species, but other species in the family use compounds such as dimethyl disulfite (the smell of rotting flesh), octane-derivatives (smells of fungi), and indole and phenols (also present in herbivore feces). The sticky-sticky spores get attached to the unknowing insects, effectively turning them into silver bullet -solutions to the problem of finding a suitable habitat patch from the vast tundra landscape. Even though flies provide a crucial service for the mosses, they get nothing in return; the colorful divas of the tundra are not generous.

Probably Polytrichastrum hyperboreum (I forgot to write down the species when I took the picture), with something that looks a lot like mycorrhiza. But it’s not! Mosses are not known to form true mycorrhizal symbioses. The fungi colonizing the moss might well be a species capable of forming mycorrhizal symbiosis with vascular plants, but here it is likely just degrading the senescent bryophyte stem. In fact, the ability of ecto- and ericoid mycorrhizal species to break down organic matter is an important reason for why plants capable of hosting such fungi (Empetrum, Betula, Vaccinium, just to name a few genera) can be so dominant in severely nutrient-limited environments such as in many parts of the Arctic.

The liverwort Tetralophozia setiformis mixed with what are likely Dicranum shoots. I’ve always found liverworts to be mysterious, a view which has not been weakened by the fact that many species can only be identified by microscopic features that are only observable in fresh samples. Luckily there are also easily identifiable species, such as Tetralophozia. One interesting feature of liverworts is that more than 90% of the species have oil bodies in some of their cells. Oil bodies, as their name implies, are tiny droplets of essential oils and other terpenoids. Their number and shape are some of the microscopic features used to identify liverwort species. But what is the function of these oil bodies? There are many hypotheses. They might provide protection against herbivores, pathogens, radiation, cold temperatures, and desiccation, but much research still needs to be done to verify this. In any case, terpenoids from liverworts have been demonstrated to have among antiviral, antimicrobial, and insect-repelling properties, which makes liverworts seem like a negative bunch. In many environments this cocktail of anti-life substances combined with hard-to-digest structural compounds and relatively low energy and nutrient concentrations seem to make liverworts unappealing targets to gnaw upon, especially for vertebrates.

Although some moss species are hard to identify so that microscopic characteristics and/or mature spore capsules are needed for a certain ID, others are easily recognizable. One easy species even for a beginner is Conostomum tetragonum with its bright blue-green coloration setting it apart from other species. This beautiful moss can be found growing high up in the mountains on heaths and at the edges of late-lying snow patches. Such easy species are in my opinion psychologically important for learning to identify mosses. The self-doubt caused by confusing forms of common mosses like Dicranum scoparium is most effectively remedied by the feeling of accomplishment one gets from firmly recognizing distinctive species. The characteristic blue gloss of Conostomum is caused by a mesh-like layer of wax that covers the leaf surface. One might think that being covered by wax would impair the water uptake of these plants that don’t have roots, but leaf-wax is actually a pretty common trait in endohydric mosses, i.e. mosses that can transport water within their tissues. The reduced uptake of water from the leaf surface is more than compensated by the increased desiccation resistance.

Concluding remarks

Mosses/

Are the bosses/

Me and liverworts/

Click with the frequency of a gigahertz

Bryophytes in the Arctic tundra (including its altitudinal extension in the Scandinavian mountains) exhibit an interesting variety of life cycles and life forms and partake in a multitude of ecological interactions. Getting to study them is well worth the time needed to invest in species identification.

What can genomics reveal about mountain sorrel and adaptations to life in the tundra?

By Jon Henn

During the last year, a group of us at Gothenburg including myself, Maria Fernanda Jimenez Torres, Christine Bacon, and Anne Bjorkman have been working to build a project examining genomic variation in Oxyria digynaOxyria, or mountain sorrel, is a very widespread plant that grows basically anywhere that is somewhat open and that stays cold for much of the year (see range map from GBIF below). This massive range allows us to ask really exciting questions about how this plant is adapted to variation in temperature, day length, and other local environmental characteristics. By sequencing the genomes of a bunch of individual plants from around their range, we can ask about the genetic basis of adaptation to different conditions and whether the ability to live in so many places is because of a huge amount of plasticity or a long history of local evolution and adaptation. We are hoping that what we discover will help in determining climate change response strategies to conserve diversity as arctic and alpine regions rapidly change.

As you might imagine, if we are going to sequence the genome from plants across the range of Oxyria, we need to actually collect samples to sequence. So, in the late spring of 2020 we put out a call to crowd-source collections from the International Tundra Experiment (ITEX) network and other friends from around the world. To sum up that part of the story, we have gotten a ton of collections from all around the world including Greenland, Norway, Sweden, Austria, Slovakia, and Italy. More keep trickling in, and this ended up being a great way to find samples, especially during COVID when travel logistics are not easy.

I ended up devoting about a month of my summer to collecting samples from the US Rocky Mountains from southern Colorado to northern Montana. This was a very special experience in many ways. First, I had never seen so many places in the mountains and it really gave me a great idea of how diverse the Rocky Mountains are (see map of collection locations). Second, I was able to climb mountains just about every day (Oxyria likes it cold, so it’s mostly found only above tree line). And finally, I was able to coordinate this adventure so that my partner could come along with me to work during the week and collect with me during the weekends. I had never done collection-based field work and I learned a lot in the process. It is definitely discouraging to hike all day up a mountain only to be eluded by the plant that you want, but I think that by the end of my trip, I had a really good idea of where to look for Oxyria

Sampling locations in the Rockies

To cap it all off, I was lucky enough to spend a week in Barrow/Utqiagvik, Alaska with Adrian Hill to collect Oxyria from the northern-most part of the USA. The stark beauty of the area left a lasting impression. I feel extremely fortunate to have had this summer adventure, enjoy some pretty pictures!

Using giant screws to reduce the footprint of Arctic research

By Geerte Fälthammar

In the early summer of 2021, a team of researchers and students screwed meter-long soil-screws into the tundra in Northern Sweden and Greenland. Now, one stormy –and even snowy- summer later, they are still standing. The goal was to tackle the problem of tripods that keep falling over, and that need to be carried up and down the mountain each season.

How does microclimate affect the timing of plant growth? That is the main question that I am working on during my PhD. The timing of plant growth, or phenology, is often studied by observing the plants in the field throughout a season. In this case, the observing is done by the camera. We spread these out over a mountain slope, to catch all the small differences in for instance temperature and soil moisture around the mountain. These small differences can have a big impact on plant growth. Each tiny Arctic plant experiences the climate right where they are, their microclimate.

Phenocam set up the old school way! Photo by Ulrika Ervander.

So a large part of my research project involves setting up time-lapse cameras in difficult to reach places. Each camera usually stands on a tripod. Due to the extreme conditions at our research sites we don’t want to have all cameras on tripods out over the winter, risking damage to both the tripod and of course the cameras too if the tripod falls over. Each season we therefore need to distribute all material out into our ecosystem, and then before the winter we need to take it back in. A very cost-intensive set-up which means that many people needs to be flown in for many days. This is not only a large cost for the project, but also a major impact on the environment. Wouldn’t there be a better, more permanent solution that didn’t require that much work?

The new and improved phenocam set up. Photo by Ulrika Ervander.

After some thinking, the solution was found in soil screws, usually used to lay quick foundations for fences or small buildings. They could definitely support a camera, and hopefully withstand the winter conditions in the arctic. With soil movement due to frost and melt processes, high winds and high volumes of snow moving down the mountain slopes, the soil screws could hopefully keep standing. Another benefit was that they are fully made out of steel, and with no moving parts. This means no plastic, recyclable and low maintenance, they are very hard to break. Once they are set-up, we can leave them standing for a long time, allowing for long-term monitoring at a relatively low cost. The only problem would be to get them into the ground. Soils in the north are often very shallow and filled with rocks. We would not be able to use these at all of our plots, but hopefully at most of them. As we weren’t sure beforehand, what percentage of our plots they would work for, it was a big risk!

In 2021 we could finally test them in the field. One batch shipped to Disko island, Greenland, another to Latnjajaure, the north of Sweden. After a summer of hard work we now have installed almost 60 soil screws! Our risk paid off, the screws went in easier than expected and provided a very stable base for our cameras. There are still plots with tripods, but since they are a lot fewer, we can now combine setting these up with collecting the data from our plots every season. This requires a lot fewer people and resources!

Field successes and data collection in action. Photo by Ulrika Ervander.

Making field research more sustainable is not an easy task. It often involves sacrificing time and money in researching alternatives to the current way of working, and then taking a risk to see if your new ideas work out the way you hope. Scientific projects are always limited by money, and as an early career researcher you often don’t have a large budget, or the right to decide about your budget. Creating possibilities for more sustainable research should be a priority of universities and other financiers in the scientific community. Now we are dreaming about the next steps on this journey! Maybe we could get a small wind turbine for the field station to generate more power? Or add solar panels to our cameras so they don’t use as many batteries? If you have an interesting, new idea, let us know!