On March 30th Jeff Marker, PhD student in our group, will be giving a talk on his work involving stable isotopes in spiders. He investigated the feasibility of using non-lethal samples in laboratory and field-collected spiders finding, in general, spider legs are reliable proxies for stable isotope values in whole bodies. Jeff will discuss some of the implications including more robust conservation efforts and the possibility of endangered species sampling.

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.

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 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.

Raft spider (Dolomedes sp.)

A PhD position in biology (community and food web ecology) is now open for application at Karlstad University. The project will focus on evaluating the ability of forested buffer strips to maintain cross boundaries fluxes between streams and riparian ecosystems.

The aim of the PhD project is to (i) analyse the link between riparian forest buffer width and functional diversity of riparian predator communities, (ii) define optimal buffer zones for conservation of riparian ecosystem functions, based on food web complexity and ecological niches (using stable isotopes) and (iii) use DNA-barcoding to study variation in prey preference with varying buffer width and test stable isotopes as a tool to assess riparian ecosystem functions in forestry affected landscapes.

The position is full time for four years but may be extended if department duties such as teaching (maximum 20 % of a full-time position) are included.

Last application date is 14 March 2019.

Read more and apply for the position here!


River Mörrumsån, Sweden



On Tuesday October 30, Peter Hambäck, Professor at Stockholm University, will give a seminar at Karlstad University titled “Spatial subsidies for shore-line spiders: evidence from molecular gut content analysis and stable isotopes”. The seminar will start at 13:15 in room 5F416, everyone who wants to are welcome to attend the seminar.

Dammutrivning i Nianån

Posted by Daniel Nyqvist | Dam removal

NRRV bedriver just nu flera studier av ekologiska effekter av dammutrivningar. I en studie undersöks ekologin i Gnarpån och Nianån (båda i Hälsingland) före och efter utrivningen av flera dammar. En mängd lokaler undersöks före och efter dammutrivningarna, både i de aktuella vattendragen och i opåverkade kontroller (Åtjärnsbäcken). Lokaler elfiskas för att studera förändringar i fisksamhället, bottenfauna provtas, vattenhastigheter, vattenkemi och bottensubstrat mäts in och landväxter inventeras. Dessutom har gruppen tagit vävnadsprover av fisk, flodpärlmussla, alger, terrestra växter, spindlar och akvatiska invertebrater för att undersöka förändringar i älvnärvaron av marina (eller bräkta) näringsämnen på olika platser i näringsväven.

Förra veckan revs dammen vid Sofieholms kraftverk i Nianån. Jessica Dolk är fältassistent i projektet och rapporterar om dammrivningen:

“Runt lunchtid torsdagen den 24/8 tog grävmaskinen sin första ansträngning för att avveckla Sofieholms kraftverk som utgjort ett vandringshinder i Nianån sedan 1909. Efter att smidigt tuggat sig igenom tuben var det dags att riva ut den gamla dammen. Många hade samlats för att följa händelseförloppet, både lokalbefolkning och sportfiskare, samt media.

Innan man rev dammen och släppte på vattnet elfiskades den gamla torrfåran (som nu blir huvudfåran) och fåran nedanför kraftverket för att sumpa fisken för att sedan släppa tillbaka den. SVTs Mitt i naturen fanns på plats, så också Sportfiskarna som följde utrivningen med kameror, både från land och från luften med en drönare. Detta för att göra en film om avvecklingen av det gamla kraftverket

Nianån hyser stora biologiska värden och genom utrivning och återställning gynnas b la havsöring, flodnejonöga, sik och andra vandrande arter, samt stationära organismer. Projektet med avvecklingen som nu alltså står klart ger havsöringen tillgång till tusentals kvadratmeter lekbottnar.

I och med avvecklingen kommer även ett tre hektar stort naturreservat att bildas.”

Dammen vid Sofieholms kraftverk i Nianån rivs.

En spindel av släktet Dolmedes, funnen under provtagningarna.

Denis Lefage och Rachel Bowes provtar evertebrater.

Rachel Bowes has recently joined the NRRV-research group. Here she writes about her previous work and what she intends to do as a postdoc at Karlstad University:


Rachel Bowes (right) with Brendan Martin, sampling algae.

“Hello! I’m Rachel Bowes and I am so excited to be joining NRRV! I just wanted to take a moment and tell you a little about me and my previous research. I have always had a deep appreciation and fascination for the natural world, and this has developed over the years into an insatiable desire to learn everything I possibly can about it. Not only do I want to discover, but I want to share these findings with everyone, and protect the Earth that I care about so much.

I completed my doctorate in May 2016 from the Department of Ecology and Evolutionary Biology at the University of Kansas (KU). My dissertation was entitled: Temporal Analysis of River Food Webs. Rivers and their tributaries are the arteries of the planet, pumping freshwater to wetlands and lakes and out to sea. Understanding energy flow up trophic levels, nutrient cycling pathways, and relative importance of terrestrial and aquatic carbon sources supporting aquatic consumers in large river food webs is essential in planning for wildlife conservation, environmental protection, and floodplain management. The principal goal of my dissertation was to understand better the factors controlling the complexity of river food webs through time.


Rachel Bowes (right) with Holly Lafferty, seining for fish in the Kansas River.

At a shorter time scale, I first looked at how season and food availability affect fish in rivers. I employed bulk tissue stable isotope analysis to determine trophic position of fish in the field, over different seasons, and fish in the lab, under different amounts of nutrient stress.

In the remaining chapters of my dissertation, I utilized a new technique, applying nitrogen and carbon stable isotope analysis of amino acids to samples to determine trophic position and carbon food sources over time.  First, I demonstrated the utility these new methods in a controlled feeding experiment in the laboratory, determining fish trophic positions. I showed that the new methods seemed to offer more accuracy and precision in trophic position estimates when compared to more traditional methods of bulk tissue isotope analysis. With these new analytical methods, I proposed multidimensional metrics for use with compound specific analyses of food webs, as well as other multidimensional community measures (e.g., fatty acids, ordinal traits). Then, I evaluated long-term historical changes in trophic position and food sources of fish museum specimens using amino acid stable isotope analyses of both the Mississippi and Ohio rivers.


Rachel Bowes (right) in the laboratory at University of Kansas.

Rivers are among the most extensively altered ecosystems on earth. Over 60% of the world’s large river basins are now affected by dams for irrigation, urban development, navigation, and energy production. Many countries are recognizing the negative implications of these impoundments and are now actively removing dams. For my post-doc research here at Karlstad, I will be using my expertise in stable isotopes to look at river connectivity and the implications of dam removal on river ecosystems. There are several potential facets that we will be looking at, including fish movement, population genetics, and transfer of nutrients from marine to freshwater to terrestrial ecosystems. Stay tuned for more developments coming soon!

If you want to follow my current research and its progress, learn more about specific projects I have been involved in previously, or read about my diverse teaching experiences, please visit my website: rebowesecology.com. You can also follow me on Twitter @EcologyRachel.”