“Half-time” Thesis presentation by David Åhlén

The 19 of November David Åhlén presented results from the Buffer project and the Management project as part of his “half-time” seminar in his thesis-work at Stockholm University. Opponent was Professor Riccardo Bommarco, SLU. It was a combined live and zoom event and we got to hear interesting discussions on invertebrate food we dynamics at wetland shorelines/flood zones, and effect of management regimes on species abundance and distribution.

A paper on interesting findings from the biodiversity surveys of 2020-2021 has been submitted

Today we submitted the first paper in the project. It is a popular science paper, consisting of a compilation with commentaries on interesting findings from the biodiversity sampling. It was submitted to the Swedish Entomological Society´s Journal; “Entomologisk tidskrift”. The title is: “Insekter och spindlar i anlagda våtmarker: Intressanta fynd från en systematisk undersökning i Uppland och södra Halland” (Insects and spiders in constructed wetlands: Interesting findings from a systematic survey in Uppland and southern Halland).

Conference and work shop in Stockholm

The whole project group attended a conference at Stockholm University (Multi-functional wetlands) the 27 of October and thereafter a 2-day workshop with ca 20 researchers discussing a joint paper on Constructed wetlands and synergies and trade-offs of wetland functions. A very good and rewarding 3-day event at Stockholm University and Tovetorp research station. Below are some photos from the conference and the workshop.

Second sampling of invertebrates for 2021

Today David arrived in Halmstad for sampling with Malaise traps and pitfall traps in the 14 wetlands that we will empty next year. This sampling toghether with another sampling next year before emptying will serve as comparisons with samplings done after the lowering of the water levels.

David loads the car with Malaise-traps and other field equipment at our office.

Sorting and identifying organisms continue…

The sorting work is progressing within the project with additional groups fully identified . The very large spider material is now identifed by Raul Vicente, and the dance flies (Empididae) by Sven Hellqvist. Examples from the two organism groups are shown below. Planning for this year’s studies is also in full swing. As we have received funding for nutrient analyzes in Uppland from Bolincentret’s RA3 and RA7, as well as the Albert and Maria Bergström Foundation, we will be able to collect very interesting data to investigate the impact of nutrients on spider and insect communities. We have also received funding for a drought experiment in Halland from Bolincentret’s RA8, and it will be very interesting to see how drought affects spiders’ condition and food preferences.

All the Crane flies (Tipuloidea) are now identified and counted

Another group of insects from the Malaise traps survey in 2020 has now been identified. it is the Crane flies, where we found a total of 47 species in Halland and 39 species in Uppland. Of these, 7 were new species for Halland and 4 new species for Uppland. The most exciting species was Paradelphomyia nigrina, which is a northern species and has only been found a few times in Finland and once each in Sweden (Dalarna) and Norway. The species was found in our traps in Uppland, and identified by Michael Andersson, Sweden’s leading expert on Crane flies. He has also taken the photo below

New species for Sweden in our sampling!

The first results from last years sampling of invertebrates have now been delivered by the experts that have spent the winter sorting, counting and identifying the specimens. One group that has been done so far is the family of dancing flies (Empididae). Among the specimens was a species never encountered in Sweden before! It is the fly Hilara manicata. Apart from this new species for Sweden, also 3 new species for the County (Halland) were found. Several organsim groups remain to be counted and identified, e.g. spiders and beetles and it will be interesting to see if we get more surprises.

Sorting of samples

Now the sorting of the samples is on the way. Victor Eriksson is hired to sort out the groups of interest, that will later be sent out to experts for species determination.


The collection of arthropods is done for 2020! The season has been very rewarding, with more than 550 samples collected between the 75 total wetlands in Halland and Uppland.


When doing sampling close to livestock, you always have to anticipate setbacks. The cattle at this location close to Båstad on the border between Halland and Skåne, showed a particular interest in trampling the Malaise trap, twice!

Last collection this year

The last collection of the year in Halland is now on the way with Malaise trapping and suction sampling. Just east of Halmstad, close to Årnarp we found this Wasp spider (Argiope bruennichi) which is a rather recent immigrant to Sweden.

Collection spiders

In Uppland we are also collecting spiders for gut content analyses. The process is similar to that of the suction sampling, only we are using an InsectaZooka and exchangeable collection socks to minimize the cross-contamination risks, as well as cleaning the equipment with bleach. This concludes the sampling period in Uppland for 2020 in late-August.

Third collection

The third and last leg of collection is on the way, with Malaise-, and pitfall trapping, as well as with suction sampling in both Uppland and Halland. Seen here is the pitfall trap that measures 7cm in diameter and 6.5cm deep, and is filled with soapy water; mounted at Senneby wetland, close to the Baltic coast north of Stockholm.

Second collection

The second collection, with more Malaise-trapping in both Uppland and Halland is now in action. After the hot-streak during the midsummer week, we hope to find plenty of insects around the wetlands. This picture is taken at Hemmesta sjöäng, a reconstructed wetland east of Stockholm.

Inverted leaf blower

Collecting ground living arthropods using an inverted leaf blower is an effective way to gauge the density of their communities. The spiders and insects that get sucked up is transferred to a white tub, from which it is easy to pooter-out the individuals of focus.

Arthropod collection

The start of the years arthropod collection! The collection methods we use are suction sampling, pitfall trapping, and Malaise trapping. The tent-like trap is a Malaise trap, invented in the 1930’s by René Malaise, and optimized for catching flying insects. The collections will be done at 25 wetland locations in Uppland, and 50 in Halland (see distribution in Project Area section). This trap is placed at a constructed wetland at the Bergianska garden, just west of Stockholm University.

BioWetland is launched

Welcome to BioWetland!

Wetlandscapes & Biodiversity – Buffer, Biodiversity and Bees

Research on how constructed wetlands(CWs) function hydrologically in a river basin perspective and how hydrology and its interactions with wetland design, location and management affect the biodiversity in wetlands and at the landscape level, with focus on arthropods in terrestrial-aquatic boundaries and pollinators.