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.
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).
Figure 1. Roots of different diameters after heat treatment. The roots on the left were cooked in boiling water for 10 minutes, the roots on the right were not treated with heat. Red color indicates viability
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)!
Figure 2. Species-rich road verge in Värmland invaded by Garden Lupine
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!
Fig. 1 View on river Vramsån, Scania, Sweden
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
Fig. 2 Field assistant Anna Elmlund on her way to bring trout to their new place to stay
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.
Fig. 3 Different modes of plant dispersal throughout an ecosystem. Derived from Haldre S Rogers, Noelle G Beckman, Florian Hartig, Jeremy S Johnson, Gesine Pufal, Katriona Shea, Damaris Zurell, James M Bullock, Robert Stephen Cantrell, Bette Loiselle, Liba Pejchar, Onja H Razafindratsima, Manette E Sandor, Eugene W Schupp, W Christopher Strickland, Jenny Zambrano, The total dispersal kernel: a review and future directions, AoB PLANTS, Volume 11, Issue 5, October 2019, plz042, https://doi.org/10.1093/aobpla/plz042
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).
Fig. 4 Hanna and Jacqueline surrounded by tanks with pooping trout and minnows
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!
a
b
(Fig. a) shows the wind traps in place for 40 hours of seed catching while (Fig. b) shows one of the water traps, just taken out of the water
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.
Daniel Nyqvist from Politecnico di Torino will be giving a seminar entitled Fish movement and behavior in industrial waters – electromagnetism, noise and ecohydraulics on Tuesday 31 May 2022 at 13.15 CEST over zoom https://kau-se.zoom.us/my/kaubiology.
Daniel’s current research focuses on fish behavior and ecology in regulated rivers. Also, he is interested in movement ecology, effects of acoustic noise and electromagnetism on fish behavior, conservation, and the connections between ecology and socioeconomics.
Jason Lee Anders, a Postdoc researcher from CEES, Oslo will be giving a seminar entitled “Effects of dietary shift and intestinal helminths on the gut microbiota of two sympatric rodents in urban environments“. Cities are among the most extreme forms of anthropogenic ecosystem modification and urbanization processes that exert profound effects on animal populations through multiple ecological pathways. Understanding how urbanization alters the gut microbiome of wildlife is essential as it plays a pivotal role in health and development. The focus of this project is to understand how the gut microbiota of two sympatric species of rodents, the omnivorous large Japanese field mouse (Apodemus speciosus) and the relatively more herbivorous grey red-backed vole (Myodes rufocanus), is altered within urban ecosystems and what factors may be affecting those changes. Both species exhibited an expanded dietary niche width within the urban areas potentially attributable to novel anthropogenic foods and altered resource availability. We detected a dietary shift in which urban A. speciosus consumed more terrestrial animal protein and M. rufocanus more plant leaves and stems. These changes in resource use may be associated with an altered gut microbial community structure such as an increased abundance of the presumably probiotic Lactobacillus in the small intestine of urban A. speciosus. While urbanization negatively impacted several intestinal helminth species (i.e. lower prevalence and abundance), the cosmopolitan nematode Heterakis spumosa may be important for maintaining high gut microbial alpha diversity. Furthermore, it may promote lower relative abundance of the potentially pathogenic Helicobacter in the lower gastrointestinal tract of urban M. rufocanus. Together, these results suggest that even taxonomically similar species may exhibit divergent responses to urbanization with consequences for the gut microbiota and broader ecological interactions.
Lutz Eckstein, professor at Karlstad University, is involved in a recently published paper, studying techniques for control of the invasive Garden Lupine (Lupinus polyphyllus) and the introduction of target species in mountain meadow plant communities.
This paper with Wiebke Hansen as the lead author, published in the journal Restoration Ecology (https://doi.org/10.1111/rec.13682), tested the restoration techniques “seed bank activation” and “green hay transfer” in combination with “manual removal of the invasive L. polyphyllus” on three types of grassland (Nardus grassland, mesic and wet mountain hay meadows) in the Rhön UNESCO Biosphere Reserve in Central Germany.
The main implications for restoration practice are the following:
Green hay application might not be a suitable tool for restoring Nardus grassland since small species might not be able to grow through the plant material layer.
Lupinus polyphyllus cover on restoration sites can be reduced by manual removal of all parts of the plants, but a lasting reduction requires at least repeated applications
Reinvasion of Lupinus polyphyllus into restoration sites must be prevented with an appropriate management, e.g. early and/or repeated mowing.
Active restoration through seed bank activation failed to promote mountain meadow target species and reduced the cover of wet mountain hay meadow target species.
Dr. Tom Staveley, an aquatic ecologist and a researcher from SLU Aqua, Sweden will be giving a talk entitled Coastal seascapes and seagrass ecosystems on Tuesday 10 May at 13.15 CET over zoom. Tom’s research interest is in marine landscape ecology concepts and applications, particularly fish ecological connectivity using methods such as acoustic telemetry. You can visit Tom’s page to read more about his research interest and publications.
Road verges act as important refuges for grassland species since the areas of semi-natural grassland have declined during the last century. However, as linear habitats, road verges increase connectivity in fragmented landscapes, which also makes them prone to colonization by non-native species. This is currently seen as the greatest threat to species-rich road verges. The invasive Garden Lupine is commonly found in road verges where it alters competitive interactions, reduces native populations, and even causes extinctions of native species.
This project is funded by The Swedish Transport Administration (Trafikverket) and the aim is to improve ecosystem functions and services of species-rich road verges and green infrastructure through evidence-based control and monitoring of Garden Lupine at the landscape scale.
During this seminar, I’m going to introduce the background for the project, and talk about what has been done and what I am planning to do in the next years.
The seminar will be streamed live over zoom on Tuesday 26th April at 13.15 CET. The zoom link for the seminar is https://kau-se.zoom.us/my/kaubiology. You are welcome
Dr. Navinder Singh, a researcher at SLU Silva will be giving a talk about Movement ecology on Tuesday XX th April at 13.15 CET over zoom. Navinder’s research focuses on Moose and how spatio-temporal variation in environment, human influence and life history interact to influence the demography and population dynamics of moose and their movement ecology. Navinder’s seminar is entitled “Movement ecology”. You can visit Navinder’s page to read more about her research interest. You are welcome to join this seminar free of charge via https://kau-se.zoom.us/my/kaubiology.
RivEM – Karlstad University
… is a research group associated to the subject of Biology and the Department of Environmental and Life Sciences at Karlstad University, Sweden. We conduct both basic and applied research on human impact on river ecosystems, and how this impact can be minimized.
In Swedish the research group is called Naturresurs Rinnande vatten (Acronym NRRV, hence the url nrrv.se).
