Johan Watz, Assistant Professor at Karlstad University, recently published two papers on juvenile salmonid ecology:

 

Temperature‐dependent competition between juvenile salmonids in small streams

By Johan Watz, Yasuhiko Otsuki, Kenta Nagatsuka, Koh Hasegawa & Itsuro Koizumi, published in the journal Freshwater Biology.

In the abstract, the authors write:

Johan Watz, doing field work during his PostDoc in Japan.

1) Biotic interactions affect species distributions, and environmental factors that influence these interactions can play a key role when range shifts in response to environmental change are modelled.

2) In a field experiment using enclosures, we studied the effects of the thermal habitat on intra‐ versus inter‐specific competition of juvenile Dolly Varden Salvelinus malma and white‐spotted charr Salvelinus leucomaenis, as measured by differences in specific growth rates during summer in allopatric and sympatric treatments. Previous laboratory experiments have shown mixed results regarding the importance of temperature‐dependent competitive abilities as a main driver for spatial segregation in stream fishes, and no study so far has confirmed its existence in natural streams.

3) Under natural conditions in areas where the two species occur in sympatry, Dolly Varden dominate spring‐fed tributaries (cold, stable thermal regime), whereas both species often coexist in non‐spring‐fed tributaries (warm, unstable thermal regime). Enclosures (charr density = 6 per m2) were placed in non‐spring‐fed (10–14°C) and spring‐fed (7–8°C) tributaries.

A forest stream on Hokkaido, northern Japan.

4) In enclosures placed in non‐spring‐fed tributaries, Dolly Varden grew 0.81% per day in allopatry and had negative growth (−0.33% per day) in sympatry, whereas growth rates were similar in allopatry and sympatry in spring‐fed tributaries (0.68 and 0.58% per day). White‐spotted charr grew better in sympatry than in allopatry in both thermal habitats. In non‐spring‐fed tributaries, they grew 0.17 and 0.79% per day and in spring‐fed tributaries 0.46 and 0.75% per day in allopatry and sympatry, respectively.

5) The negative effect of inter‐specific competition from white‐spotted charr on Dolly Varden thus depended on the thermal habitat. However, there was no strong evidence of a temperature‐dependent effect of intra‐ and inter‐specific competition on white‐spotted charr growth.

6) Multiple factors may shape species distribution patterns, and we show that temperature may mediate competitive outcomes and thus coexistence in stream fish. These effects of temperature will be important to incorporate into mechanistic and dynamic species distribution models.

 

Read more about the Koizumi lab at Hokkaido University (where Johan did his PostDoc) on their website!

 

Structural complexity in the hatchery rearing environment affects activity, resting metabolic rate and post‐release behaviour in brown trout Salmo trutta

By Johan Watz, published in the Journal of Fish Biology

In the abstract, Johan writes:

The effects of structural enrichment in the hatchery rearing environment of brown trout Salmo trutta was linked to post‐release performance. Enrichment resulted in reduced swimming activity scored in an open field test and reduced movement in a natural river after release. Also, enrichment increased resting metabolic rates, which correlated positively with overwinter growth.

 

Contact the author to access the papers.

 

The left photographs show Dolly Varden (a) and white‐spotted charr (b). The right photographs show enclosures in a non‐spring‐fed (c) and a spring‐fed (d) tributary.

 

The structurally enriched (left) and barren (right) tanks used in the study on how structural complexity in the hatchery environment affects juvenile brown trout.

 

River Rottnan in winter.

Yves P. Klinger, Sarah Harvolk-Schöning, Lutz Eckstein, Wiebke Hansen, Annette Otte and Kristin Ludewig recently published the paper ”Applying landscape structure analysis to assess the spatio-temporal distribution of an invasive legume in the Rhön UNESCO Biosphere Reserve” in the journal Biological Invasions.

Lutz Eckstein, Professor in Biology at Karlstad University, writes about their work:

The legume Lupinus polyphyllus. Photo by Lutz Eckstein

“We applied a combination of aerial mapping and GIS-based landscape analysis to study the invasion of the legume, Lupinus polyphyllus, in the Rhön UNESCO Biosphere Region as a case. We assessed the changes in lupine distribution between 1998 and 2016 in a strictly protected part of the Biosphere Region by means of landscape structure analysis. The area invaded by L. polyphyllus doubled from 1998 to 2016. The number of lupine stands decreased by 25%, but average stand size increased by 300%. In 2016, large and well-connected mesic grasslands that were situated close to roads were more heavily invaded than small and remote wet grasslands. Our results show that landscape composition plays an important role for the spread of invasive plants. Specifically, invasive stand characteristics, such as stand size, form, and connectivity, are crucial for driving the invasion process. Therefore, in addition to landscape composition, invasive stand characteristics should be included in the planning of conservation measures. Overall, aerial mapping combined with landscape analysis provides a cost-effective and practical tool for landscape managers to prioritize invasive control measures.”

Access the paper here, or contact any of the authors.

European eel, Anguilla anguilla

On Tuesday 18 June, Niclas Carlsson, lab/field technician and master student at Karlstad University, will give a seminar titled: “Low-sloping racks and the importance of bar spacing for eel passage”. The seminar starts at 13:15 in room 5F416 at Karlstad University. Everyone who wants to are welcome to attend the seminar.

 

 

 

Jacqueline Hoppenreijs recently joined the NRRV research group. Here she writes about her previous work and what she intends to do as a PhD student at Karlstad University:

Hej! I’m Jacqueline Hoppenreijs and I recently started my PhD in the NRRV group at Karlstad University. During my MSc, which I did at the Department of Environmental Science at Radboud University in Nijmegen (the Netherlands) and the Department of Ecology at SLU Uppsala, I worked on different species groups: plants, birds and insects and wrote two theses. The first one, with fellow student Bas van Lith, explored possibilities for bird population restoration on the Indonesian island of Java, using historical sources on bird population development and land use change over the course of a century. During the second one, I studied the importance of different man-made habitat types for pollinators in Sweden, over the course of a season.

 

Bas and I birdwatching in Rancaekek, by Fachmi Azhar Aji

 

Despite studying quite different time frames and taxa, biodiversity, ecosystem functioning and conservation have been recurring themes. Coming from the overpopulated Netherlands, I find myself very interested in the interface of human society and nature, and more specifically nature restoration, conservation efforts and their ethical aspects.

As a junior researcher at the Department of Animal Ecology & Physiology at Radboud University, I dove a bit deeper in the influence that human actions can have on the natural world. I worked in Rob Leuven’s group to identify the potential risks of invasive (alien) species in horticulture, biological control and food forestry.

As from April 2019, I’m working with Lutz Eckstein and Lovisa Lind. We’re focusing on both fundamental and applied aspects of plant ecology and I’m looking forward to unravel the mechanisms that drive plant dispersal and community composition in boreal riparian zones. Next to that, I’m excited to be part of an active education environment and the passionate group of researchers that forms the NRRV, and can’t wait to meet the rest of Karlstad’s community!

 

Vegetation sampling on Omey Island, by Joop Schaminée

Seke Chainda

Global Swede is an initiative by the Swedish government to promote long-term relations with international students in Sweden, with the aim to create cross-border networks and future collaborations.

Seke Chainda, Master student in Biology at Karlstad University, was awarded as Global Swede 2019 together with 25 other international students studying in Sweden. The students have distinguished themselves in their areas of study and in terms of both innovation and entrepreneurship. They have therefore been deemed good representatives for both Sweden and their home countries. Seke Chainda is from Senanga, a town in western Zambia. On 21 May, Seke visited the Ministry of Foreign Affairs (Utrikesdepartementet) in Stockholm to participate in the Global Swede ceremony. Seke received his diploma from Ann Linde, the Swedish Minister for Foreign Trade.

 

 

 

 

Thomas Blom (Pro-Vice-Chancellor at Karlstad University), Seke Chainda and Stina Eriksson (Vice Head of the Biology Department at Karlstad University) at the Global Swede Ceremony

Seke is enrolled in the Master programme in Ecology and Conservation Biology at Karlstad University. In his master’s thesis, he examined the function of the adipose fin for the swimming performance and drift-feeding capability of juvenile salmonids, which usually is removed from juvenile fish reared at hatcheries for stocking purposes.

 

Seke Chainda, Erik Petersson (Professor at the Swedish University of Agricultural Sciences) and Elio Bottagisio (master student) doing lab work at Karlstad University

Seke Chainda together with other master students conducting field work

Seke Chainda tagging a fish

On 28 May (tomorrow), Martin Österling, Associate Professor at Karlstad University, will give a seminar titled:

“The genetic structure of mussels with complex life cycles and its relation to host fish migratory trait and density.”

The seminar starts at 13:15 in room 5F416 at Karlstad University. Everyone who wants to are welcome to attend the seminar.

Anna Hagelin and the opponent Professor Ian Fleming, Memorial University of Newfoundland, Canada, at Anna’s PhD defense

Anna Hagelin successfully defended her PhD thesis with the title “Conservation of landlocked Atlantic salmon in a regulated river: Behaviour of migratory spawners and juveniles12 April this year.

Anna also presented her research at “forskningspodden” (the research podcast), which is a popular science podcast at Karlstad University. Here you can listen to Anna talk about her research on salmon conservation in river Klarälven (in Swedish).

European eel, Anguilla anguilla. Photo: Jörgen Wiklund

Karlstad University has an opening for a PhD position in aquatic conservation biology. The project will focus on “Resolving production bottlenecks for the European eel”. Conserving biodiversity is one of the major challenges in applied aquatic ecology. The European eel functions as a flagship species in marine and freshwater conservation, and its population collapse is of major concern for ecologists, fishers and managers.

The aim of the PhD project is to identify:

(i) relationships between yellow eel habitat use, growth, behavior and survival.

(ii) effects of habitat characteristics and the surrounding landscape on eel large-scale movements within freshwater systems.

(iii) functioning downstream passage solutions at hydropower plants for a wide range of silver eel phenotypes.

The position is full-time for four years. Doctoral students may also be assigned departmental duties, such as teaching, which will extend the period of employment accordingly.

Read more and apply for the position here.

Last day to apply is 5 June 2019.

Seminar Tuesday 14 May

Posted by Karl Filipsson | Seminar

Tomorrow Tuesday 14 May, Lina Polvi Sjöberg, Assistant Professor at Umeå University, will give a seminar at Karlstad University:

“What controls the physical habitat template and disturbance regime of streams? — understanding sediment transport and channel form of semi-alluvial streams in northern Sweden”

The seminar starts at 13:15 in room 5F416.

Everyone is welcome to attend the seminar.

On Monday and Tuesday 6 – 7 May, Dr. Helen Kopnina from The Hague University of Applied Sciences, Netherlands, will visit Karlstad University. During her visit, Helen will give two talks:

 

Monday 6 May, 13:30 in room 1D350

Sustainable development goals – A critical evaluation in theory and educational practice

 

Tuesday 7 May, 13:15 in room 5F416

Ethical debates in biological conservation

 

Everyone that wants to are welcome to attend the seminars.