Louis Addo (Ph.D. Student at Karlstad University)

Louis Addo (Doctoral Student), Mahboobeh Hajiesmaeli (Post-doctoral Researcher), John Piccolo (Professor) and John Watz (Associate Professor in Biology) all from the River Ecology and Management Research Group RivEM, Department of Environmental and Life Sciences at Karlstad University have recently published a paper entitled “Growth and mortality of sympatric Atlantic salmon and brown trout fry in fluctuating and stable flows” with the journal Ecology of Freshwater Fish.

In their paper, they explore the potential effects of hydropeaking or short-term regulated rivers on the growth and mortality of sympatric Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) at the fry life stage.

This paper is open-access and can be found at https://onlinelibrary.wiley.com/doi/epdf/10.1111/eff.12685

Professor John Piccolo was involved in two recently published articles and a podcast about ecological sustainability.  The two articles and the podcast are part of a larger project on ecological sustainability that John is part of,  with researchers from around the globe.

The focus of the research is on sustaining biodiversity in social-ecological systems, and on understanding social and ecological values.  Upcoming events include a webinar organized by the Society for Conservation Biology Europe Section https://conbio.org/groups/sections/europe/activities-fall-2021-webinar-series/ And the 2022 European Congress for Conservation Biology (ECCB) in Prague, Czech Republic: https://www.eccb2022.eu/ The network is always interested in developing new partnerships, so feel free to contact John (john.piccolo@kau.se.) if you are interested.

To read both papers, visit:

https://www.frontiersin.org/articles/10.3389/fcosc.2021.761292/abstract and

https://www.mdpi.com/2673-7159/1/4/22

You can listen to the podcast interview via https://open.spotify.com/episode/4gk0dTO4ng0MXf9Whhlnai

Mattias Hansson, Lovisa Lind, Andreas Vernby, Larry Greenberg and Johan Watz from Karlstad University have a new paper out! It describes how Hester-Dendy samplers perform under different flow regimes. This was tested in a laboratory experiment by studying the colonization of the Hester-Dendy samplers in relation to a predetermined benthic macroinvertebrate composition in a fluctuating (and increasing) flow regime and in a constant flow regime.

An aquarium setup for the fluctuating and increasing flow regime with a Hester-Dandy sampler on the bottom. Photo by Mattias Hansson.

The results showed that flow conditions didn’t affect the number of colonizing individuals, but the sampled species diversity was negatively affected by the fluctuating flow regime. This indicates that sampling benthic macroinvertebrates from rivers and streams with sub-daily flow changes, for example downstream of hydropeaking power plants, may be subject to a negative sampling bias.

You can read the full paper here: https://onlinelibrary.wiley.com/doi/10.1002/rra.3805.

Professor Lutz Eckstein is co-author in a new paper in the journal Applied Vegetation Science led by Yves Klinger (Justus-Liebig-University Giessen, Germany). The authors assessed the role of mowing machinery and endozoochory by migratory sheep as dispersal vectors in semi-natural grasslands by comparing the species compositions and traits of species found in the vectors to the regional above-ground vegetation and soil seed bank. Plant material from mowers (n = 12 from one date) and dung samples from migratory sheep (n = 39 from 13 dates) were collected and the dispersed plant species were determined using the emergence method. We compared the species compositions to the regional above-ground vegetation and seed bank using non-metric multidimensional scaling (NMDS) and indicator species analysis. Furthermore, we compared functional traits of the dispersed species to traits of non-dispersed species of the regional species pools by calculating log-response ratios and performing metaregressions.

Sheep in the Rhön Mountains. Photo by Yves Klinger.

We found that mower samples were more similar to the above-ground vegetation whereas dung samples were more similar to the seed bank. Mowers and sheep endozoochory favored the dispersal of species with different traits and phenologies. Species with small seed sizes were prevalent in both vectors. Mowers were less selective concerning most traits, but favored high-growing grasses such as Alopecurus pratensis and Trisetum flavescens. Sheep dung samples contained less grasses and more palatable species, such as Urtica dioica.

Log-response ratios dispersal vectors vs species pools of sheep vs above-ground. LDMC = Leaf Dry Mass Content, EIV N = Ellenberg Indicator Value for Nutrients. Zero indicates the mean value of the non-dispersed species from the respective species pool, bars show mean log-response ratios ± confidence intervals. Figure is part of Figure 3 in the paper.

Sheep endozoochory and mowing machinery are complementary dispersal vectors favoring species with differing functional traits. Sheep endozoochory enables dispersal of species that have unfavorable traits (e.g. low releasing heights) or phenologies for dispersal by mowing machinery. To ensure the dispersal of a high number of plant species in semi-natural grasslands, the interplay of different vectors should be considered.

Read more about the paper here: https://doi.org/10.1111/avsc.12579.

Professor Lutz Eckstein is involved in a new article led by Eva Svensson (Dept. of Political, Historical, Religious and Cultural Studies, KaU) and co-authored by Jan Haas (Geomatics, KaU) in the journal Landscapes (Taylor & Francis). They tested the potential of a low-budget method for integrating information on human impact and natural responses in the vegetation of boreal forested Scandinavia. The information from two national databases in Sweden – the National Inventory of Landscapes in Sweden (NILS) covering surveyed vegetation, and the Register of Ancient Monuments (Fornsök) – were combined and visualized using Geographical Information Systems (see Figure).

Rännberget, Northern Värmland, close to the study area described in the paper. Photo taken by Lutz Eckstein.

No relationships between human impact and vegetation were found at any of the five investigated sites. The authors discuss potential reasons for this, among others mismatches in time and scale between databases but also sectorized survey methods not paying attention to biocultural heritage, landscape perspectives or long-term processes. The paper concludes that further development of survey methods and registers targeting contexts and processes are called for. “This is a good example of `negative´ results, i.e. a study that does not demonstrate any significant patterns being published in an international scientific journal”, says Lutz Eckstein. Read more about the paper here: https://doi.org/10.1080/14662035.2020.1905202.

A group of international researchers, among which Martin Österling, have a new paper out! The authors, led by Ronaldo Sousa from the University of Minho in Portugal, investigated the role of anthropogenic habitats as refuges for freshwater mussels. The dataset of 709 sites comprised 228 mussel species, of which 34 are threatened, in a broad variety of anthropogenic habitat types. The authors assessed the conservation importance of these anthropogenic habitats, which included both refuges and ecological traps, and provide guidance for the conservation of freshwater mussels. Read the full paper here: https://onlinelibrary.wiley.com/doi/10.1111/gcb.15549

Irrigation canal in Morocco (river Bouhlou) colonized by Margaritifera marocana, one of the rarest species on the planet. Photo by Ronaldo Sousa.

Andrew Harbicht, Martin Österling, and Olle Calles from Karlstad University and Anders Nilsson of Lund University have a new paper out. By radio tagging Atlantic salmon smolt and following them along their downstream migration to the Baltic, they quantified the effect of both a dam and a reservoir on migratory rates while accounting for environmental covariates. The good news for salmon, if reservoirs are kept thin (river-like), and mitigative measures are taken at a dam (i.e., spilling water during the smolt migration), the effects of anthropogenic barriers can be dramatically reduced. Read more about the paper here: https://doi.org/10.1002/rra.3760

Tired of slugs eating fruit and veggies in your garden? Big holes in your strawberries? Johan Watz and Daniel Nyqvist (Politecnico di Torino, Italy) have a new paper out on the performance of copper and waterglass (sodium silicate) barriers against movements of Spanish slugs (Arion vulgaris).

Copper foil barriers delayed, but did not prevent slug passage. Waterglass, on the other hand, prevented passage completely and reduced crop damage in a semi-field validation. You can read the full paper here: https://www.sciencedirect.com/science/article/pii/S0261219420304580

Lutz Eckstein, professor at Karlstad University, is involved in two recently published papers, studying the effects of invasive Garden Lupine (Lupinus polyphyllus) on vegetation and seed bank of mountain meadow plant communities.

The first paper together with Wiebke Hansen (first author), Julia Wollny, Annette Otte and Kristin Ludewig, published in the journal Biological Invasions (https://doi.org/10.1007/s10530-020-02371-w), found that the invasion of Garden Lupine homogenizes vegetation composition. The similarity among plots increased with increasing lupine cover in three different vegetation types. L. polyphyllus affected species diversity in terms of richness and effective species number but in rather complex ways, i.e. plots with low to intermediate lupine cover had higher species diversity than control plots. Probably, the invasion though Garden Lupine is linked to significant species turnover. A very clear effect was found for community-weighted means of species trait. In all three vegetation types studied, the canopy height of the community increased with increasing lupine cover, whereas especially in the low-productive Nardus grasslands, leaf dry matter content decreased and specific leaf area increased. Thus, the Garden Lupine shifted the suite of community traits towards more competitive trait values. This may lead to overall more productive plant communities from which rare, low-growing herbs and grasses will disappear.

Germination experiment from the seed bank study in the paper published in Restoration Ecology. Photo: Kristin Ludewig

The second paper with Kristin Ludewig (first author), Wiebke Hansen, Yves Klinger, and Annette Otte, published in the journal Restoration Ecology (https://doi.org/10.1111/rec.13311), analyzed the effects of increasing cover of Garden Lupineon the seed bank of mountain meadows, and the potential of the seed bank of these stands for active restoration of mountain meadows in terms of species composition and number. The authors conducted a seed bank analysis on 84 plots with increasing cover of L. polyphyllus in three mountain-meadow types of the Rhön Biosphere Reserve, Germany. Seedlings from 119 species germinated from the seed bank samples, including 17 Red List species but only a few seedlings of L. polyphyllus. While the influence of L. polyphyllus on the current vegetation was visible, no effects on the seed bank were apparent. L. polyphyllus had no influence on total seed density, seed density of typical mountain-meadow species, or species numbers in the seed bank. Only the seeds of the Red List species were significantly related to the cover of L. polyphyllus. The authors conclude that the seed bank offers potential for active restoration of species-rich mountain meadows, but species absent from the seed bank have to be added by other measures.

Kristin Ludewig, Wiebke Hansen and Yves Klinger will presents these and other results from a large restoration project in the UNESCO Rhön Biosphere Reserve at the RivEM week.

Our former PhD student Anna Hagelin and several other researchers, amongst them Larry Greenberg, Olle Calles and Eva Bergman, recently published a new paper in the Canadian Journal of Fisheries and Aquatic Sciences.

They examined fishway passage of landlocked Atlantic salmon in River Klarälven, Sweden and brown trout in River Gudbrandslågen, Norway, and the influence of prior experience on passage success in 2012 and 2013. Fishway trap efficiency varied from 18 to 88% and was influenced by river discharge. Most salmon (81%) entered the fishway trap on days without spill, and salmon moved from the turbine area to the spill zone when there was spill, with small individuals showing a stronger reaction than large fish. Analysis of fish with and without prior trap experience showed that a higher percentage of the “naïve” fish (70% of salmon and 43% of the trout) entered the fishway traps than the “experienced” ones (25% of the salmon and 15 % of the trout). Delays for fish that entered the trap ranged from 3-70 days for salmon and 2-47 days for trout.

The paper is not publicly accessible, but can be requested via ResearchGate.