River Ecology and Management


Biology – Karlstad University

17

JUN 2021

New paper out: Landlocked Atlantic salmon in a large river–lake ecosystem: managing an endemic, large-bodied population of high conservation value

Posted by Louis Addo | Conservation, Ecology, and Evolution of Nonanadromous Atlantic Salmon

Two current members of NRRV, Larry Greenberg and Eva Bergman, and two former members, Johnny Norrgård and Pär Gustafsson, have recently published an overview of 15 years of research on the endemic, large-bodied population of landlocked River Klarälven-Lake Vänern population of Atlantic salmon (Salmo salar).

Large bodied adult Atlantic salmon from Lake Vänern

They highlight the major findings from studies of each of the salmon’s life stages and conclude that the Klarälven salmon population is below carrying capacity. Greenberg et al. (2021) suggest measures to increase the number of spawners and downstream passage success, and they also recommend habitat restoration to compensate for losses from, for example, former log-driving activities. They also discuss the ecological and legislative problems that need to be addressed if one wishes to re-establish salmon in Klarälven’s upper reaches in Norway. Managing, conserving and conducting research on this migratory salmonid population has been challenging not only because of the ecosystems’ large size, but also because there is more than one anthropomorphic stressor involved.

Read more about the paper here: https://cdnsciencepub.com/doi/full/10.1139/cjfas-2020-0163

(B) Schematic diagram showing the different phases of the salmon life cycle in relation to the hydropower dams and the different studies undertaken in the River Klarälven – Lake Vänern ecosystem

17

JUN 2021

Contribution to an Issue on nonanadromous Atlantic Salmon: “Conservation, Ecology, and Evolution of Nonanadromous Atlantic Salmon”

Posted by Louis Addo | Canadian Journal of Fisheries and Aquatic Sciences

Professor Larry Greenberg, NRRV, and William Ardren, US Fish & Wildlife Service, have co-edited a special issue on nonanadromous Atlantic Salmon in the Canadian Journal of Fisheries and Aquatic Sciences. The issue is entitled “Conservation, Ecology, and Evolution of Nonanadromous Atlantic Salmon” and has contributions from experts from North America and Europe, consisting of 13 papers. The papers cover four themes, namely (1) ecology, evolution, and behavior, (2) conservation and management (3) improving hatchery programs and (4) re-introduction efforts. Three of the papers come from NRRV researchers;

 1.     https://cdnsciencepub.com/doi/abs/10.1139/cjfas-2019-0271

2.     https://cdnsciencepub.com/doi/full/10.1139/cjfas-2020-0163

3.     https://cdnsciencepub.com/doi/abs/10.1139/cjfas-2020-0155 

Larry Greenberg and William Ardren have written a general overview of the 13 papers in a paper entitled ‘Introduction to “Conservation, Ecology, and Evolution of Nonanadromous Atlantic Salmon”. This can be found at: https://cdnsciencepub.com/doi/full/10.1139/cjfas-2021-0035

Maximum reported age and maximum fork length for globally distributed populations of nonanadromous Atlantic salmon (A). Closed circles represent an extreme example of the variation observed at these life-history traits with the Ouananiche Beck population from Newfoundland that has a maximum length of 13 cm (B — photo credit Dylan Fraser) and the Gullspångsälven population from Lake Vänern in Sweden that has a maximum length of 108.5 cm (C — photo credit Fredrik Nilsson). Data for this figure are from Hutchings et al. 2019

17

JUN 2021

New paper out: The impact of livestock grazing and canopy gaps on species pool and functional diversity of ground flora in the Caspian beech forests of Iran.

Posted by Louis Addo | Applied Vegetation Science

Professor Lutz Eckstein is senior author in a new paper in the journal Applied Vegetation Science led by Zahed Shakeri (Kassel University, Germany). Livestock grazing is still an important disturbance in many forest ecosystems of the world. While studies have addressed the general impact of different grazing and light intensities on temperate forest ecosystems, little is known about how the combination of these two factors can affect the species pool and functional diversity of temperate forests.

Cattle grazing in a canopy gap in a beech forest in northern Iran . Photo by Zahed Shakeri

The authors studied vegetation and environmental data of 104 relevés from Oriental beech forests (Fagus orientalis) of northern Iran. These were assigned to four groups based on their light and grazing intensities. Non-metric multidimensional scaling was used to analyze vegetation compositional relationships among groups. They used nine functional traits related to growth, reproduction, and survival for a total of 147 plant species. Redundancy analysis of community-weighted means was used to determine the response of single traits to disturbance and environmental variables. Both light and grazing intensities significantly affected species pools, single traits, and functional divergence. Suites of trait attributes including hemicryptophytes, therophytes, grass-like, hygromorphic leaves, insect-pollinated, rhizomes, and runner plants were associated with high-light sites. In closed-canopy (low-light) sites, the strong filtering effect of shade resulted in suites of trait attributes including taller plants, macrophanerophytes, scleromorphic leaves, simple leaves, and berry fruits. While high-light sites had a larger species pool, they exhibited less functional diversity. Cattle grazing can mediate the filtering effect of light, and increase functional diversity in both low-light and high-light sites. Conservation measures in this region should acknowledge that moderate traditional cattle grazing combined with individual-tree and group-tree selection in these forests may maintain or even enhance functional diversity in these valuable ecosystems.

Read more about the paper here: https://doi.org/10.1111/avsc.12592.

Oriental beech forest in Northern Iran. Photo by Zahed Shakeri

8

JUN 2021

Seminar coming up: Parasitic Freshwater Mussels and their Effects on Host Fishes

Posted by Jacqueline Hoppenreijs | Naturresurs rinnande vatten, Project LIFE Connects, Research, Seminar

On 15-6-2021 Sebastian Rock will be giving a talk introducing his work on the host-parasite interactions of unionid mussels. Within the broader LifeConnects projects, this work will improve mussel conservation and reintroduction efforts of this little studied order of bivalves in Sweden and around the world.

River Vramsån, a spot for future mussel reintroduction (photo by Sebastian Rock).

The seminar starts at 13.15 and will be streamed live over Zoom. Contact Olle Calles (olle.calles@kau.se) to receive the zoom link to this seminar.

27

MAY 2021

New paper out: The suitability of Hester-Dendy macroinvertebrate samplers in fluctuating flows.

Posted by Jacqueline Hoppenreijs | Papers

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.

24

MAY 2021

New paper out: Mowing machinery and migratory sheep herds are complementary dispersal vectors for grassland species.

Posted by Jacqueline Hoppenreijs | Papers

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.

20

MAY 2021

Seminar coming up: How does landscape change affect plant diversity?

Posted by Jacqueline Hoppenreijs | Seminar

On 25 May, Sara Cousins, professor in Physical Geography and associate professor in Plant Ecology at Stockholm University, will give a talk entitled “How does landscape change affect plant diversity?”. Sara combines plant community ecology and landscape history to improve the understanding of how land use changes affects plant dispersal and community composition, and also focuses on how climate change affects these processes.

The seminar starts at 13.15 and will be streamed live over Zoom. Contact Olle Calles (olle.calles@kau.se) to receive the zoom link to this seminar.

4

MAY 2021

New paper out: Integrating Nature and Heritage in the Boreal Forests of Scandinavia? Exploration of a Low-Budget Method

Posted by Jacqueline Hoppenreijs | Naturresurs rinnande vatten, Papers, Research

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.

8

APR 2021

New paper out: The role of anthropogenic habitats in freshwater mussel conservation

Posted by Jacqueline Hoppenreijs | Freshwater mussels, Nyheter, Papers, Research

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.

31

MAR 2021

Seminar coming up: Sexually antagonistic genes in flies and humans

Posted by Jacqueline Hoppenreijs | Seminar

On 6 April, Ted Morrow will give a talk entitled “Sexually antagonistic genes in flies and humans”. Sexually antagonistic selection occurs when natural selection on traits shared by males and females operates opposite directions in the two sexes. Sexually antagonistic genetic variation is apparently common and taxonomically widespread and yet very few specific genetic loci have been identified. The talk will give an overview of experimental work that has been carried out in the Morrow lab to find these genes in the fruit fly model as well as ask why no sexually antagonistic genes have been reported from humans.

The seminar starts at 13.15 and will be streamed live over Zoom. Contact Olle Calles (olle.calles@kau.se) to receive the zoom link to this seminar.