Arctic charr habitat in northern Iceland.

On Tuesday 5 November, Stefán Óli Steingrímsson, Professor at Hólar University College, Iceland, will visit Karlstad University and give a seminar titled “Salmonid behaviour in space & time: Some lessons from Iceland”. The seminar starts at 13:15 in room 5F416 at Karlstad University. Everyone who wants to are welcome to attend the seminar.

Hjaltadalur valley on northern Iceland, seen from Hólar.

Jeff (right) and a former colleague inspecting Santeria sacrifices in Miami, Florida, USA. Santeria worshipers use a variety of plants, herbs, and animals to perform religious sacrifices. Some hypothesize that the very invasive African land snail (Achatina fulica) was brought into the United States to use in these rituals. Photo by Kelsey Branch

Jeff Marker recently started his PhD at Karlstad University. Here he writes about his previous work and what he intends to do as a PhD student at Karlstad University:

“Hej and hello, my name is Jeff Marker and I am a PhD student here at Karlstad University in the NRRV Research Group. Originally hailing from the Great Plains region of the United States, I am now settled here in Sweden working on riparian ecology, food webs, spider predation, and forestry policy. I began my academic career focused on tropical plant science questions, specifically the best ways to grow and maintain a year round seed corn nursery in Hawaii. After a short stretch in the agribusiness industry, I turned my attention to invasive pests and plant disease monitoring with the United States Department of Agriculture.  As a Plant Protection and Quarantine Officer I was tasked with enforcing USDA quarantine laws related to invasive species, agricultural smuggling, and agricultural trade compliance. It was here that I rediscovered my love of insects, especially the beetles. Over the years I amassed a large working and personal collection of beetles from the Cerambycidae and Buprestidae families from the Midwest and Great Plains regions of the U.S. Eventually I left the beetles behind, put on a suit and tie, and ended up in Washington D.C. as an agricultural policy analyst where I focused on international quarantine regulations and the agricultural quarantine inspection process.

After meeting a wonderful Swedish woman and taking stock of my life, I was easily convinced to move to Gothenburg in 2016. Upon moving to Sweden, I restarted my graduate education and completed my MSc here at KAU through the Ecology and Conservation Biology Program. My thesis focused on the effects of urban areas on Swedish beetles that utilize dead or decaying wood for all or part of their life cycle. I believe that urban areas have a mixed, but often overlooked, effect on insect biodiversity. On one hand increased urbanization and a focus on specific types of habitat removal (i.e. dead or decaying wood) can be a direct threat to ecosystem health and/or function. However, urban areas often have significantly more plant and arthropod diversity when compared to the surrounding natural, managed, and rural landscapes. And while urban areas can be prone to invasive pest outbreaks and poor management decisions, with proper care and monitoring they also have potential to become biodiversity hotspots and some of the most resilient ecosystems in the face of a changing climate and changing attitudes about nature.

Jeff in Gothenburg admiring some giant hogweed/jätteloka (Heracleum mantegazzianum), a European and North American invasive species with the potential to cause a severe phototoxic effect on human skin. Photo by Johanna Jonstrand

As a researcher at KAU I will combine my love of arthropods and my background in public policy to analyze forestry management practices and their effects on riparian ecosystems. While here I hope to share my knowledge about insects and agriculture but more importantly, I am excited to learn about spiders and cutting edge genetic techniques including stable isotope analysis and DNA-barcoding. Under the supervision of Eva Bergman, Lutz Eckstein, Ann Erlandsson, Rachel Bowes, and Denis Lafage I will carry out a range of experiments to examine the link between riparian forest buffer width and its effect on predator community functional diversity, riparian ecosystem function, and food web complexity.  Currently I am conducting feeding experiments on wolf spiders (Lycosidae) to determine the time that specific prey DNA is detectable in their guts after predation events. This lab experiment will act as a primer for our future field studies in the Värmland and Örebro areas that will include intensive ecosystem sampling of terrestrial and aquatic communities. Our project will collaborate closely with forestry stakeholders, Swedish country administrative boards, Skogsstyrelsen, and other scientists involved in similar work. Ultimately we will work with these same groups to craft riparian buffer strip guidelines that intersect the needs of Swedish forestry with the health of Swedish riparian ecosystems to help build on sustainable forestry concepts.

Outside of the research arena I spend my time teaching my daughter to love and respect all the småkryp and playing and collecting board games. If you ever want to talk beetles or board games feel free to swing by my KAU office any time. You can follow my research and occasional musing on Instagram or Twitter both @sverige_saps.”

250+ wolf spider females in the lab at KAU. Inset: a Pardosa sp. (Lycosidae) paralyzing a collembola prey. Photos by Jeff Marker

On Tuesday 8 October, Ann Erlandsson, Assistant Professor at Karlstad University, will give a seminar titled “DNA barcoding of spider gut contents”. The seminar starts at 13:15 in room 5F416. Everyone who wants to are welcome to attend the seminar.

The paper led by scientists of the Department of Engineering and Chemical Sciences, Karlstad University, was co-authored by Lutz Eckstein, professor of biology at the Department of Environmental and Life Sciences.

He writes about their work:

“Sweden has about 28 million hectares of forests, and pine trees constitute 40% of the total standing volume. Since the country is the world’s second largest exporter of pulp, paper and wood products, a total of 400 million containerized tree seedlings are produced by Swedish forest nurseries to restock forests each year. However, intensive annual forest harvests remove essential soil nutrients, which may cause problems for forest productivity.

In Sweden, container-grown seedlings are dominantly produced in peat and peat-based growth media. Peat-based substrates have many advantages such as long-term drainage ability, good aeration for tree seedling roots, good fertilizer absorbance and release capability. However, peat-based media are considered non-sustainable as their extraction have adverse environmental impacts. Therefore, sustainable approaches towards forest production and plantation management are urgently needed.

Therefore, the aim of this paper was to study the effects of hydrochar, derived from paper mill biosludge, on growth, quality, mycorrhizal associations and nutrient/heavy metal uptake of pine tree seedlings. We analyzed whether effects varied significantly between hydrochar forms (powder or pellets) or hydrochar proportions mixed with peat (10% or 20% hydrochar v/v). The effects of hydrochar addition on pine tree seedling was evaluated under three fertilization regimes (no fertilizer, 50% fertilizer and 100% fertilizer). We hypothesized that the growth, quality and mycorrhizal colonization of pine tree seedlings grown in substrate mixed with hydrochar would improve. We also expected pine tree seedlings grown with hydrochar to require less fertilizer to achieve similar or higher growth, mycorrhizal colonization and associated nutrient uptake relative to seedlings grown without hydrochar but with optimum rates of fertilizer (100% fertilizer). To our knowledge, this current study is the first paper to explore the potentials of hydrochar powder and pellets for being used as a growing media component in production of containerized pine tree seedlings.

Application of hydrochar had positive or neutral effects on shoot biomass and stem diameter compared with control seedlings (without hydrochar) under tested fertilizer levels. Analysis of the natural logarithmic response ratios (LnRR) of quality index and nutrient and heavy metal uptake revealed that application of 20% (v/v) hydrochar powder or pellet with 50% fertilizer resulted in same quality pine seedlings with similar heavy metal (Cu, Ni, Pb, Zn and Cr) and nutrient (P, K, Ca and Mg) contents as untreated seedlings supplied with 100% fertilizer. Colonization percentage by ectomycorrhizae significantly increased when either forms of hydrochar were applied at a rate of 20% under unfertilized condition. The results of this study implied that application of proper rates of hydrochar from biosludge with adjusted levels of liquid fertilizer may reduce fertilizer requirements in pine nurseries.”

Read the paper for free here! 

On Tuesday 24 September Ryan Lepak, Postdoc at the University of Wisconsin-Madison and the United States Environmental Protection Agency, will give a seminar at Karlstad University entitled: “Use of Stable Isotope Signatures to Determine Mercury Sources in Aquatic Ecosystems”. The seminar starts at 13:15 in room 5F416. Everyone who wants to are welcome to attend the seminar.

On Friday 20 September, Ivan Olsson, Senior Project Manager at the County Administrative Board (länsstyrelsen) Skåne (and former RivEM PhD student), will give a seminar titled “LIFE CONNECTS – River connectivity, habitats and water quality towards restored ecosystem services“. The seminar starts at 10:00 in room 5F416. Everyone who wants to are welcome to attend the seminar.

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.