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:

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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.

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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.

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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.”