River Ecology and Management


Biology – Karlstad University

1

JUN 2025

New paper: How Do Salmon and Trout Handle Life in a River Rollercoaster? New Study Reveals Surprising Answers

Posted by Louis Addo | Papers

By Louis Addo, Lise Meneboo, Mahboobeh Hajiesmaeili, John J. Piccolo & Johan Watz

Flume setup for observing juvenile salmonids, featuring cobble substrate, spatial gridlines, and a flow-through refuge structure.

In the world of riverine fish, life isn’t always calm and flowing. In fact, for young Atlantic salmon and brown trout, the river can sometimes feel like a wild rollercoaster ride—especially in areas impacted by hydropeaking, where dam operations cause rapid and frequent changes in water flow.

Experimental flume used to study juvenile salmonid behavior under controlled flow. The setup includes cobble substrate, red gridlines for spatial tracking, and a black refuge structure on the left. Flow enters from the left.

A new peer-reviewed study led by Louis Addo and colleagues at Karlstad University investigates how sudden shifts in flow affect the foraging behavior, social dynamics, and habitat use of young salmon and trout. The study’s twist is that it examines whether it matters whether the two species were raised together (sympatric) or separately (allopatric).

What Did They Find?

Contrary to what many ecologists might expect, the study found that:

  • Rapid flow fluctuations did not impact how well the fish could forage for drifting food.
  • Group composition, not flow, was the big game-changer when it came to social spacing (nearest neighbor distance) and microhabitat selection.
  • Salmon stayed closer to the bottom of the tank regardless of conditions, suggesting a preference for stable positions, while trout were more mobile, especially when raised with salmon.

So, does hydropeaking make life harder for juvenile salmonids? Not necessarily. The findings suggest that as long as the water stays within a certain range of temperatures and flows, the fish adapt surprisingly well.

Why does this matter?

Many environmental models that simulate salmon and trout populations often leave out behavioral details like social spacing and microhabitat selection under changing flow. This study provides encouraging news: those simplifications may not lead to big errors, at least when it comes to modeling energy intake and growth.

In other words, salmon and trout parr seem to hold their own in fast-changing rivers, using different strategies to navigate their environment—some stick together, some spread out, some hug the substrate—depending on who they’re with.

Big Picture

As river managers, ecologists, and hydroelectric developers look for ways to balance renewable energy with aquatic biodiversity, studies like this are crucial. They remind us that behavioral flexibility in fish may be a powerful buffer against environmental change—though we shouldn’t assume they’re invincible.

This paper is open access and can be downloaded on https://onlinelibrary-wiley-com.bibproxy.kau.se/doi/epdf/10.1002/rra.4464

11

MAR 2025

PhD Defense: Ecosystem Engineering by Freshwater Mussels:

Posted by Louis Addo | Okategoriserad

Raviv Gal, a PhD student at the Department of Environmental and Life Sciences, will defend his PhD entitled “Ecosystem Engineering by Freshwater Mussels: Effects on macroinvertebrate communities, decomposition processes, and fish behaviour.” The date and venue are shown on the poster below. You are all welcome to this event.

Raviv Gal

28

FEB 2025

New paper out about the optimal mowing time for the invasive Garden lupine based on species phenology and nutrient dynamics

Posted by Louis Addo | Papers

Elin Blomqvist and Lutz Eckstein are main and senior authors, respectively, of a paper that studied the links between phenology and biomass and nutrient dynamics in the invasive herb Lupinus polyphyllus to identify the optimal timing for control mowing along road verges. The paper, which has recently been published open access in the journal Basic and Applied Ecology (https://doi.org/10.1016/j.baae.2025.02.006), was a cooperation between Karlstad University and Justus Liebig University Giessen (Germany: Yves P. Klinger and Till Kleinebecker).

The main findings of the study were that biomass and nutrients of Lupinus polyphyllus in the roots are lowest during the flowering phase and that shoot-to-root ratios peak during flowering and the seed ripening phase. Therefore, control mowing during flowering and before seed dispersal will weaken the plants the most. Generally, the planning of control management of this invasive species by mowing should be based on the species’ phenology.

The pictures show Lupinus polyphyllus in three different phenological phases in which control through removal of above-ground biomass is expected to be most effective.

15

JAN 2025

Seminar: Ecosystem services as an analytical framework: it can help to answer questions of management, planning and policy

Posted by Louis Addo | Seminar

On 21 January, Jan Vermaat will be giving a seminar to our department with the title “Ecosystem services as an analytical framework: it can help to answer questions of management, planning and policy”. His work centers on ecosystem services, catchment biogeochemistry and floodplains as well as macrophytes.

Jan Vermaat

Jan is a professor at the Department of Environmental Sciences of the Norwegian University of Life Sciences and research dean at the Faculty of Environmental Sciences and Natural Resource Management. He will be visiting our department on 21 and 22 January. The seminar will take place on 21 January, at 13:15 CET in 5D307 and on https://kau-se.zoom.us/j/65816884688!

16

DEC 2024

New paper out about the effects of the invasive Garden lupine on vascular plant diversity of road verges of high conservation value

Posted by Louis Addo | Papers

Lutz Eckstein is senior author of a paper showing that the invasive herb Lupinus polyphyllus significantly reduces the richness of vascular plants along valuable road verges in Sweden. The paper, which has recently been published open access in the journal Nordic Journal of Botany (https://nsojournals.onlinelibrary.wiley.com/doi/full/10.1111/njb.04438), is led by Juliana Dániel-Ferreira (SLU Uppsala). The study was a cooperation between Karlstad University and SLU (Swedish Biodiversity Centre – CBM) and is partly based on data collected by Karola Knudsen during her Master thesis at KaU.

One interesting finding of the study was that even though the direction of the effect of Garden lupine on vascular plant diversity was similar in both studied areas in Sweden, the magnitude was strongly dependent on the preexisting communities. The study area in the west (Värmland, Örebro) hosted a lower proportion of competitive species typical for nutrient poor soils compared to the area in the east (Västmanland, Uppland) (Fig. 1). The authors conclude that invasion by L. polyphyllus is a serious threat to vascular plant communities but that the response is context dependent. Communities with high abundance of vulnerable and poor competitive plant species should be prioritized for eradication and control of the invasive.

Fig. 1. Total plant occurrences belonging to the four categories of competitive ability in each type of plot for (a) the entire dataset, (b) the west area, and (c) the east area. No = plots without lupine, yes = plots dominated by lupine.

3

SEP 2024

PhD Defence: Rooting for riparian vegetation – processes underlying community composition in boreal ecosystems

Posted by Louis Addo | Research, riparian vegetation, Students

On 13 September, 10:00 AM, Jacqueline Hoppenreijs will defend her PhD thesis. The thesis, titled Rooting for riparian vegetation – processes underlying community composition in boreal ecosystems, covers the roles of hydrology and geomorphology in dispersal and environmental filtering of riparian vegetation, and builds on four papers:

1. Pressures on Boreal Riparian Vegetation: A Literature Review https://doi.org/10.3389/fevo.2021.806130

2. Seed dispersal of riparian plants: mapping hydrochory across hydrology and geomorphology

3. Effects of dispersal and geomorphology on riparian seed banks and vegetation in a boreal stream https://doi.org/10.1111/jvs.13240

4. Riparian vegetation in a regulated and a free-flowing river: effects of stream size, order and tributaries

The full thesis can be downloaded from DiVA. The defence is open to the public, and it is possible to follow it on our campus and on Zoom. Please contact jacqueline.hoppenreijs@kau.se for more information. 

18

JUN 2024

Call for abstract: Artificial Intelligence and Ecosystem Services – Advancements in AI in the field of ecosystem services for transformative change

Posted by Louis Addo | Conference

We (V. van ‘t Hoff & P. Cabral & F. O. Akinyemi, et al.) would like to bring to your attention an exciting session at the upcoming ESP Europe 2024 conference.

Conference Session: Artificial Intelligence and Ecosystem Services – Advancements in AI in the field of ecosystem services for transformative change
Date: 18-22 November 2024
Location: Wageningen, The Netherlands
Abstract Submission: Open from 15 May to 15 July 2024 (https://espconference.org/europe2024/home)

Hosted by: Felicia O. Akinyemi, Pedro Cabral, and Vince van ‘t HoffCo-hosts: Sara Alibakhshi, Bruna Almeida, Jan Haas, Ewa Orlikowska, Xi-Lillian Pang, Mieke Siebers, Guojie Wang Aim: This session explores the transformative potential of AI in understanding, monitoring, and managing ecosystem services (ES). It will highlight innovative AI solutions, such as satellite image analysis and natural language processing, which offer new ways to gather and analyze complex data. The session will cover various AI methodologies, including machine learning, deep learning, and GeoAI, and discuss their applications in assessing and modelling ES and ecosystem functions (EF).

For more information and to submit your abstract, please visit the ESP Europe 2024 website.

Why to attend?

1) This session is an excellent opportunity to stay at the forefront of advancements in AI and its applications in ecosystem services. I highly encourage you to attend and consider contributing your knowledge.


2) The communications presented at this session may be considered for inclusion in a synthesis paper or a review paper highlighting knowledge gaps in the use of AI for ecosystem services in both empirical and modelling contexts.

23

FEB 2024

Seminar: Ecomorphological effects of experimental floods in an alpine river: insights from the long-term e-flow program on the Spöl River

Posted by Louis Addo | Seminar

On 27 February, Gabriele Consoli will be giving a seminar to our department with the title Ecomorphological effects of experimental floods in an alpine river: insights from the long-term e-flow program on the Spöl River. His work centers on the ways in which large wood and flow management affect rivers and their ecological functioning. Having a background in ecology and geomorphology, he now works as a postdoc at the River Ecosystems research group at the University of Lausanne (Switzerland), where he combines abiotic, biotic and drone data to find out how flow affects the geomorphology and ecology of streams.

Read more about the River Ecosystems research group on their website and join us for the seminar on 27 February at 13:15 CET via  https://kau-se.zoom.us/j/65816884688

13

FEB 2024

Seminar: Ploughs, cows and heterogeneity across scales: Creating biodiverse landscapes

Posted by Louis Addo | Seminar

On February 20, Dr. Frank Jauker will be giving a talk about his work on agricultural landscapes and biodiversity promotion at the Justus Liebig University in Giessen, Germany. He will specifically present the GreenGrass project, where many societal stakeholders work together to improve grazing management, with the ultimate goal of making dairy production more sustainable.

Figure 1: View at one of the study sites in the GreenGrass project.

Attend the seminar via Zoom: https://kau-se.zoom.us/my/kaubiology, at 13:15 CET on February 20.