Hello everyone, thanks for checking our blog, I’m Mariette and I will keep you updated on our research.
Two weeks ago we arrived at Ivalo Airport, at least 4 of us, as two students decided to take the long economic travel with buses and trains. We picked them up in Ivalo and in two takes we drove to the Kevo Subarctic Research Station, our stay for the next five weeks. I have never been to Finnish Lapland or even Finland so I was amazed by what I saw. Finland is overwhelmingly green, with beautiful rivers and lakes. The good weather was of course playing a role in this as well. Every now and then there are a couple of reindeer walking next to or on the road and the smell of the trees is really nice. To put it in perspective, I’m from the Netherlands and the forest cover there is about 11 percent, which is 3,650 km2. In Finland the forest cover is about 74 percent, which is 225,000 km2. But you might know this already. This at least gave us a lot of excitement to start with our research.
In the first week we selected the sites where would like to run our experiments. The aim of our research is to understand the ecological conditions that trigger tree regeneration and expansion in the boreal and tundra region. Vegetation might shift due to climate warming and a possibility is that the boreal forest might expand in the direction of the tundra. Our main question is whether shrubs facilitate tree seedling establishment under contrasting permafrost conditions. To answer this question we are setting up our experiments in palsa mires. The palsa mires consist of elevated features with patches of permafrost, the palsas, and a poorly drained wet environment without permafrost, the mire. The palsas support shrub vegetation, which differs in height and density per palsa, depending on the amount of permafrost.
Selecting sites is an interesting thing to do. I discovered how the Finnish mountains looked like from the top, how not to sink in the mire and how nice it is to walk with a couple of ecologist through a certain ecosystem and stop everywhere where someone sees something interesting. You probably recognize the trips you make with friends that are not ecologists/biologists or something like that and they think it is quite odd to stop for every little interesting nature phenomenon. Our quest for suitable sites made me realize that I’m not the only one who is doing that, which is quite nice, also to share your thoughts and interests.
We decided with the help of Harri, a professor at the University of Helsinki who has also worked with Milena and Juul in Southern Finland, that we could conduct two experiments in addition to our correlational studies. After this big discussion the professors left and we, the students, are now on our own. This might sounds scary to leave the research in the hands of four students, but for us, or at least for me, it felt as excitement, now it will finally really starts. We are enough prepared, we practiced almost every measurement and talked trough the protocols so everything will work out fine.
In the second week we started setting up the experiments. In the first experiment we aim to assess the role of shrubs on the establishment of seedlings from four tree species on pounu with and without permafrost. Pounu is a Finnish word that is used for small palsa features. The tree species we will study are Betula pubescens (Mountain birch), Picea Abies (Norway spruce), Pinus sylvestris (Scots Pine) and Larix Sibirica (Siberian larch).
In Vaisejaggi and in Pulmankijarvi-jaggi we started a planting experiment in two palsa mires with contrasting reindeer browsing. At each site we have selected 15 pounu with and without permafrost. On each pounu we laid out four plots of 20x40cm. Two plots were situated at the top of the pounu, whereas the other two were placed at the edge of the pounu. Before we removed the vascular plants in half of the plots we assessed the species in each plot with the help of our own made herbarium. Within these plots we will plant seedlings and seeds of our four tree species. We will also record environmental measurements, such as the soil temperature, soil moisture, irradiance, aboveground biomass and nutrient availability. After 3 weeks and next year we will assess the emergence of seeds and survival of seedlings.
In the second experiment we want to assess the potential effect of voles on seeds and seedlings of the four tree species. In the same palsa mires, but further away from the planting experiment, we started a cafeteria experiment. At each site we selected 15 additional pounu with and without permafrost. On top of each pounu we established two plots. Effect of voles on seeds and seedlings will be assessed by recording damage on seeds/seedlings offered inside the plots. Vole presence will be recorded by three techniques: counting vole burrows within a 1.25 m radius from the middle of the selected pounu in experiment 1, so the voles are not disturbed in experiment 2, track-camera’s for 6 pounu for 5 days at each site and death trapping for all pounu in experiment 2 for 2 days per site using the same trapping lure as that is used by Kevo station to assess vole densities.
In addition to the above experiments, we will also collect leaves of 22 tree species in the arboretum experiment of the Kevo station to assess epigenetic variation between the collection sites. The collecting sites are all in a different environment. The variation will tell us something about how well the tree species adapt to their environment. We expect that the variation between species will be higher if the trees adapted to the environment than when they did not adapt. The tree species were planted about 40 years ago and they used all species that were treeline species somewhere in the world.
This week we started planting in experiment 1, which means that we had to count the seeds and put them in tubes in groups of five. After one day of counting, we started planting the seedlings and seeds in both Vaisejaggi and in Pulmankijarvi-jaggi. The planting gave me the feeling of normal gardening but then in the arctic. Although we had to work long days, the realization of experiment 1 gave us an exciting and satisfied feeling. At the end of this week we will also start the cafeteria experiment in Pulmankijarvi-jaggi. Hereafter, all our experiments are running.
Thanks for visiting this blog, I will keep you updated!