On 13 September, Aafke Schipper will be giving a seminar with the title Biodiversity modelling for policy support to our department. Her work centers on the development and application of large-scale biodiversity assessment models to understand past and future effects of anthropogenic activity on biodiversity globally, and she works on a wide range of taxa to do so.

Aafke Schippers

As an assistant professor at Radboud University and researcher at the Netherlands Environmental Assessment Agency, Aafke also informs policymakers on both the national and international level. Read about some of her current and future work on https://www.globio.info/ and https://www.ru.nl/en/research/research-news/vidi-grants-for-research-into-freshwater-fish-geometry-our-sense-of-smell-and-more, and join us for the first autumn seminar on Tuesday 12 September at 13:15 CEST via https://kau-se.zoom.us/my/kaubiology!

Emil Nordström (former Master student), together with Lutz Eckstein and Lovisa Lind published a paper studying decomposition along the bog-forest edge (also known as “lagg”) using the tea-bag-index.

This paper, which was based on Emil Nordström’s Master thesis, is published in the journal Ecosphere (https://doi.org/10.1002/ecs2.4234). The authors studied the mass losses (90 days) of green and rooibos tea bags placed across the bog-forest transition of six bogs in Dalarna (Sweden). Three 20-m transects, each containing seven pairs of tea bags, were buried across the margins of each bog, centered at the edge of the Sphagnum moss (Figure 1). The results confirmed their hypothesis, showing a strong edge effect across the bog-forest transition (Figure 2).

Figure 1. Placement of tea bag pairs relative to the bog edge, where 0 m indicates the edge between bog and forest
Figure 2. Interaction between where tea bags were placed relative to the edge of the bog, with the -10 position furthest out into the bog, and their resulting (a) stabilization factor (S) and (b) decomposition rate (k) values. The shaded area represents 95% CI of the line fit.

Soil moisture levels had the strongest negative effects on decomposition rates. In comparison to soil moisture, pH and temperature had minor or no significant effects. Plants indicative of low decomposition rates included Vaccinium oxycoccos, Drosera rotundifolia, and Sphagnum species. In contrast to other studies, the authors did not find an increase in decomposition with increased species richness among the studied bog ecosystems.

In conclusion, there is an edge effect on decomposition and maintaining or restoring the hydrology of a peatland is the most important factor for continued carbon storage. A rough estimation of an areas’ decomposition rate appears to be possible based on its vegetation.

Johan Watz (Associate Professor at University of Karlstad Biology Department) together with others from the department, DHI Sverige and Fortum Sverige have recently published an article with VATTEN- Journal of Water Management and Research. The article, entitled ” HOW MUCH WATER DO SEA TROUT NEED? A COMPARISON BETWEEN A CORRELATIVE AND AN INDIVIDUAL-BASED MODEL TO PREDICT EFFECTS OF FLOW ON STREAM FISH POPULATIONS” used both a correlative model and an individual-based fish habitat model called InSTREM 7 as a management tool to assess water requirements for salmon and trout in a river reach located below Blanka-ström hydropower plant in river Emån, Sweden.

To read more about the paper this paper visit https://www.researchgate.net/publication/363272777_Hur_mycket_vatten_behover_havsoringen_En_jamforelse_av_en_korrelativ_och_en_individbaserad_modell_for_att_forutsaga_effekter_av_floden_pa_stromlevande_fiskar

Sebastian Rock (P.h.D Student) at Karlstad University and others from the Department oF Environmental and Life Sciences and Lund University, Department of Biology – Aquatic Ecology have recently published a review article entitled “Effects of parasitic freshwater mussels on their host fishes: a review”.

The findings are heavily biased towards Margaritifera margaritifera, a unique mussel not well suited for cross-species generalizations.

This paper is open access and can be found at https://pubmed.ncbi.nlm.nih.gov/36050917/

Hej! My name is Lise Meneboo. I am a student at l’Institut Agro Dijon (France) in a 5-year degree equivalent to a master’s level. My student programme focuses on agriculture and the environment and includes a 5-month internship abroad.

That is why I was in Karlstad in the River Ecology and Management group from mid-March 2022 to the beginning of August 2022! I chose this place because I was interested in ecology, the aquatic field, fish and more. I generally wanted to discover research in this field. Here, I mostly worked with John Piccolo (my supervisor), Mahboobeh Hajiesmaeili and Louis Addo. The main projects I was involved with focused on hydropower regulation, particularly hydropeaking and its effects on fish habitat and population dynamics. I had the wonderful opportunity to be part of a modelling project, a laboratory project and a field riverbed survey in Göteborg. All these different projects aimed at improving fish habitat and population on the river reach impacted by hydropower regulation.

Prior to starting the laboratory experiment and handling fish, I took a mandatory course in animal welfare and legislation in Sweden.

Moreover, I worked on InSTREAM 7 (an ecohydraulic model shown in Figure 1), an individual-based model. The goal was to estimate the effects of peaking flows on the abundance and the growth of Atlantic salmon (Salmo Salar) and brown trout (Salmo trutta) in the Gullspång Rapids, a residual flow stretch in the hydropower-regulated Gullspång River in Sweden. In fact, this modelling software is a useful tool to understand and manage fish population responses to short-term flow fluctuations.

Concerning the lab experiment, the main focus was to determine the effects of short-term flow fluctuations and flow changes on the drift-feeding behaviour of Atlantic salmon and brown trout parr. Three flow treatments are used: stable flow (one or two pumps) and fluctuating flow. After each trial, all the fish are dissected to see the quantity of food in their stomach. Cameras were set at a close range to film each trial to see the behaviour of the fish (particularly at the feeding time) and their location in the aquarium.

I also had the chance to go on a field in Göteborg with my team in May 2022. We took riverbed measurements with a GPS station and measured river velocity. It was the first days of rain of my stay! However, that was nice to enjoy fieldwork with all of them.

Another goal of this internship was to improve my English and I think I did pretty well. Compared to before, my English comprehension and expression are much better today even if there is still progress to be made (maybe another time). This semester was also a wonderful opportunity to discover the Swedish culture and cultures from all over the world with so many international meetings! Furthermore, I had an amazing time discovering Sweden (and Norway!) with either some friends, my mom, or people from the department!

Finally, I want to thank John Piccolo who coordinated my internship and all the staff including other researchers, PhD students, … of the KAU biology department, in particular Louis Addo, Mahboobeh Hajiesmaeili ( a Post-Doctoral Researcher) and Johan Watz (Associate Professor). That was a great teamwork with Mahboobeh and Louis. It was such a wonderful experience to meet so many researchers and to work in a nice environment. Erasmus+ funding made this internship possible for me, so a thank you also goes to the International Office, here in Karlstad and at my study university in Dijon

Lovisa Lind, together with Andrew Harbicht (former post-doc), Eva Bergman, Johannes Edwartz (former bachelor student) and Lutz Eckstein published a paper, dealing with the potential effects of initial leaching for estimates of mass loss in decomposition studies using the tea-bag-index (TBI).

This paper, published in the journal Ecology and Evolution (https://doi.org/ 10.1002/ece3.9118), studied the short-term mass losses (3–4 h) due to initial (physical) leaching under field and laboratory conditions for green and rooibos tea using the TBI and contextualized the findings using existing long-term mass loss (90 days) in the field for both aquatic and terrestrial environments. They found a fast and considerable initial leaching rate for both tea litter types, which could be mistaken for decomposition through microbial activity. When relating these estimates of initial leaching to long-term studies, they found that up to 30–50% of the mass loss of green tea reported as decomposition could be lost through leaching alone in high moisture environments (>90% soil moisture and submerged). Not accounting for such differences in initial leaching across habitats may lead to a systematic overestimation of the microbial decomposition in wet habitats. Future studies of microbial decomposition should adjust their methods depending on the habitat, and clearly specify the type of decomposition that the study focuses on.

The left panel shows the average mass loss (%) of tea bags (green and rooibos) after 90 days of incubation in boreal riparian habitats with different soil moisture levels and the right panel shows an average mass loss (%) of tea bags after 90 days of incubation in the Mörrumsån River. Shaded regions indicate the extent of mass loss (%) by leaching after 4 h from our field data at 65%– 80% and >90% soil moisture, respectively.

Post Doctoral Researcher Mahboobeh Hajiesmaeili and others from Karlstad University’s biology department and the River Ecology and Management (RivEM) group have recently published an article (open access) entitled Individual-based modelling of hydropeaking effects on brown trout and Atlantic salmon in a regulated river where they parameterized and used inSTREAM version 7.2-SD (an individual based model with the capability of considering important fish ecological behavior) as a soft river management tool to analyze the effect of hydropeaking on juvenile fish in Lilla Åråsforsen (located downstream of the Gullspång dam along the Gullspång River in Sweden). Different scenarios of flows with and without hydropeaking were tested to access the impact of hydropeaking on growth, survival and distribution of age 0+ to 1+ juvenile brown trout (Salmo trutta) and Atlantic salmon (Salmo salar). Perhaps the most interesting finding was that hydropeaking had a modest negative effect on the survival and growth of both species but survival was more negatively affected than growth, especially in smaller juveniles. Most importantly, the study has demonstrated the potential use of IBMs for testing different research questions and assessing and prioritizing alternative management strategies in regulated rivers.

The paper is open access and can be found at https://onlinelibrary.wiley.com/doi/full/10.1002/rra.4037

Hej, my name is Hanna Paikert and I completed a three-month-long internship at NRRV. My main motivation for this internship was to gain insight into a different research environment and to expand my knowledge regarding different scientific methods. Additionally, I aimed to figure out if I want to pursue a Ph.D. (A question I can answer now: it’s a big yes!)

During my time in Karlstad, I was involved in different projects but mainly worked with Elin Blomqvist and Lutz Eckstein on the project “Evidence-based control and monitoring of Garden Lupine for the conservation of species-rich road verges”. (But see: “Fish, poop and plants: crap research isn’t as bad as it might sound.”) The Garden Lupine (Lupinus polyphyllus) is an invasive plant species originally from North America which has spread massively along road verges in Sweden. Due to its large height, its ability to fix nitrogen and the high numbers of seeds each plant can produce, it has become a threat to native biodiversity. Thus, the control of this species is of high relevance along species-rich road verges. At the beginning of my stay, I focused on the effects of heat treatment on seeds and roots of the Garden Lupine to investigate whether high temperatures could decrease the germination rate of seeds and the survival of treated root parts. This is particularly important when large soil masses, which contain seeds or roots from the Lupine are transferred from one site to another. Here we used Triphenyl tetrazolium chloride to visualize the viability of the roots and seeds after the treatment. The red color indicates viability, no staining shows a dead plant part (see figure 1).

With the beginning of summer, field season started. I joined Elin while setting up the plots for a mowing experiment which comprises eight sites all over Värmland and will go on for the next three years. The goal is to investigate the effects of different mowing heights and frequencies on the spread of the Garden Lupine, as well as the native species richness. After the experiment was set up, we started with species inventories in which I got to expand my knowledge of species identification and gained a lot of botanical vocabulary in Swedish [😊]. During my last weeks, I assisted Elin with the first round of mowing and was lucky enough to see some drone flights to visualize the spread of Lupine from the air. Due to the fact, that the sites for this experiment are located all over Värmland, I was very lucky to see a lot of beautiful places as well as some wildlife (see figure 2)!

Last but not least I want to thank my supervisor Lutz Eckstein who coordinated my stay and gave me a lot of tips for my future career, Elin Blomqvist for great times in the field and her patience in teaching me “botanical Swedish”, Jaqueline Hoppenreijs and Sebastian Rock for taking me along to the field. A big thank you goes out to the whole department who welcomed me very warmly and made me feel included from day one! It was great getting to know you and getting a sneak peek into your research!

The Scanian river Vramsån (Fig 1) has been a stage for RivEM research before, but not with the wide range of methods that Ph.D. candidate Sebastian, visiting intern Hanna Paikert and Ph.D. candidate Jacqueline tried out in May this year!

Vramsån has long been used for hydropower purposes but is now in the process of being restored to a more natural flow regime. It is one of seven rivers of interest to the LIFE Connects conservation project, which aims to improve their ecosystem functions and ecosystem services. Under six years the project will work with removal of hydropower plants and dams, create fauna passages and improve migration paths at barriers. The project also works on innovative passage solutions that enables both hydropower production and fish migration as well as riverbed restorations to gain more natural habitats and improved water quality. The goal is to improve survival and production of threatened fish species such as Atlantic salmon and European eel as well as the endangered mussel species Freshwater pearl mussel and Thick-shelled river mussel. Research and information efforts linked to river restorations within the project will constitute an important part of the project, that you can read more about on https://lifeconnects.se/!

With that in mind, the first goal of this research adventure was to collect fish and mussel specimens for a study on the impact of light pollution on the host-parasite relationship of the endangered Thick-shelled river mussel (Unio crassus) and its host the common Eurasian minnow (Phoxinus phoxinus).  

This incredibly endangered, and ecologically significant mussel has rapidly diminishing populations, something that LIFE Connects is trying to change. While many people don’t think much of these simple bivalves they play a key role in keeping environmental conditions stable. By filtering suspended particulates from the water column large populations of mussels can keep water cleaner, a benefit to both fish and humans. When they need to poop, the majority goes into the surrounding sediment, fertilizing it and improving both benthic fauna communities and plant growth. Together, these help fortify fish and bird populations. Not only does the increased plant growth provide habitat but the increase in benthic fauna provides more food sources as a large part of benthic fauna communities are comprised of the larval forms of terrestrial insects.

One of the main ways we try to prevent the Thick-shelled river mussel from going extinct is to increase the chances of their reproductive success, a complex cycle and significant factor in their population decline. These mussels are partial parasites on fish, with this extra step making their reproduction rate be quite a bit slower than other freshwater bivalves. We can help by forcefully infecting host fish with mussel larvae and keeping them safe for a large part of the reproductive cycle before releasing them back into the wild. As such the first part of this study was to go electrofishing for fish to use as hosts in for the mussels to be reintroduced, primarily minnows and trout. The trout got to stay in the river (Fig 2) while the minnows were destined to come back to KAU to be used in some experiments. More on that in another blog post

Re-naturalizing the flow regime of a river doesn’t just affect the fish and their ecological functions in it, but other processes as well. Dispersal is one of these processes, and is thought to be important for the composition of all plant communities, including those that we find in-water and in the riparian zone. There are many ways in which plants disperse (Fig 3), and a large part of Jacqueline’s Ph.D. project focuses on dispersal via water. Most of this dispersal is in the direction of the water flow, but many people overlook a tiny component: the animals in the water that swim in the opposite direction! These animals can carry seeds on their outsides or, via foraging, in their bodies. This relatively little-studied function called endozoochory builds on the thought that animals spread other species by eating them in one place and pooping them out elsewhere.

A second goal of this week was finding out whether this pathway is an important route for riparian vegetation in Vramsån. The fish that we were catching thus had a double function: not only will they be used for mussel larva infestation, but we collected their poop to compare the seeds therein with seeds and vegetation in other parts of the ecosystem (Fig 4).

Which other parts, you ask? Well, of course, fish stomachs are not the only place where you find seeds – far from that! Given that there are so many ways in which plants disperse, we planned a comparison of the seed composition in different parts of the ecosystem. So, equipped with self-built traps to filter seeds from the water (Fig. a), to catch seeds from the air (Fig. b) and loads of boxes to sample riparian litter, riparian soil and aquatic soil, we went to work!

It took some hours to get everything in place, but while Seb will spend his spring infesting his fish in Karlstad University’s (KAUs) aquarium facility, Hanna and Jacqueline are running a germination study to see which species pop up in the samples of the different ecosystem parts. After two weeks in KAUs plant growing room, over 200 seeds of at least 10 different species have germinated across the different sample types. We are giving the samples a few more weeks to see what else poops up before we’re going to try and sniff out if there’s anything interesting in there!

Regina Lindborg, a Professor from Stockholm University will be giving a seminar entitled Biodiversity and ecosystem services from grasslands – towards a more sustainable agriculture on Tuesday 7 June 2022 at 13.15 CEST over zoom https://kau-se.zoom.us/my/kaubiology.

Regina’s research focuses on the conservation of biodiversity, with a special focus on natural pastures, and how to combine the management of ecosystem services and the conservation of biodiversity with sustainable food production in the agricultural landscape. Regina works mainly with issues that are linked to landscape ecology and processes that concern large space and time scales such as changes in land use and the effects of climate change. Several of Regina’s studies are done in interdisciplinary collaboration with researchers from other disciplines, such as economics and cultural geography.