Activities

Tobias Engzell studied the water level fluctuations of constructed wetlands in relation to CW location, size and soil types. Read the paper by following the link in the title: ”Anlagda våtmarkers vattennivådynamik: Typmönster och dess samband med omgivande faktorer”

Ellen Nein studied drought effects on Diptera, Follow the link to read the paper: Hydrological drought effects on Diptera families and functional groups in constructed wetlands: Differences between sampling methods

Today we submitted a paper to ”Svensk Botanisk Tidskrift” (Swedish Botanical Journal) on the method (Stand up paddle, GIS-transects) and results from our survey of submersed vegetation in the constructed wetlands.

An article about the work by Peter and David at Stockholm University, on the invertebrates in the constructed wetlands in our project was published by TT and several newspapers. To read the article (in Swedish) follow one of the links:

https://www.ystadsallehanda.se/nyheter/spindeljakt-med-dammsugare-ger-svar-om-vatmarker-15644fe5/

https://www.svd.se/a/8J51p2/spindeljakt-med-dammsugare-ger-svar-om-vatmarker

https://www.aftonbladet.se/nyheter/a/O862kV/spindeljakt-med-dammsugare-ger-svar-om-vatmarker

This week Peter and assistant biology student Ellen Nein are doing a new sampling campaign in the 8 wetlands that were emptied this summer and the 8 controll wetlands. This follow-up sampling will also be repeated next year to study more long-term effects of droughts on the arthropod communities in the floodzones of wetlands.

The vegetation surveys of ca 25 wetlands are now finished. In total ca 15 submersed species were found, including at least 4 Charophyte species. Among the more interesting findings were the Bryozoa Plumatella repens and 2 Nitella species that are on the Redlist (NT); N. gracilis and N. mucronata. Unfortunately we also found the invasive species Elodea nutallii in some wetlands. Below are some photos of some species. It is clear that constructed wetlands in the agricultural landscape can be important also for threathened and rare plant species, and the the occurrence of invasive species is frequent.

We have started with the surveys of submersed vegetation in the wetlands. This is also part of our networking with the Cyano bacteria project at Lund University run by Pablo Pablo Urrutia Cordero. The macrophytes are surveyed every 10 meters at 2 transects perpendicular to each other in each wetland. It is always interesting to see how the planning (first photo) holds up when it meets the reality of the field work (second photo)…So far so good, Our idea with two persons on the SUP where one handles the GPS to find the right sampling site and does steering and paddling, and one person doing the actual sampling seems to work.

John had an online presentation at the 36th SIL conference in Berlin, Germany. The presentation focused on the project LIFE-Goodstream, but some results on arthropods in the flood zones and adult dragonflies from the Buffer project were also presented.

After David and Beata did the final arthropod sampling the first week in August we know have started to return the water levels to normal again. Below are some photos from David during the final sampling when the water tables were lowered.

This week David is in Halland to do the follow up-sampling in the field experiment where we have emptied 8 wetlands. He had help from an Intern from the biology course at Stockholm University, Beata Wolgers. Some maintanence of one of the Malais trap was also neccessary since the cattle can be a bit too curious.

David presented the studies on arthropods in the constructed wetland flood zones at the entomology congress in Helsinki, Finland. The poster can be seen above.

Here Sofia and Kalle do the emptying of one of the 8 wetlands. In some wetlands it is an easy process…

This week we started a field experiment where we simulate drought by emptying (lowering the water table) some wetlands. We emptied 8 wetlands and have another 8 as controls. The purpose is to see the effect of drought on the arthropod communities at the shorelines of the wetlands. Peter did the ”pre-drought” sampling with Malaise traps, color bowls, suction sampling and pitfall traps. We also took photos of the wetlands with a drone before and after emptying. After a month of dry-out we will repeat the invertebrate sampling, and also repeat it next year to study long-term effects.

The first paper from our surveys is now published. The title is: Insects and spiders in constructed wetlands: interesting findings from a systematic survey in Uppland and southern Halland, and is published in Entomologisk Tidskrift 143 (1–2): 47–66. It can be viewed and downloaded by clicking on the image below:

Today we got the news that our paper submitted to ”Entomologisk Tidskrift” has been been accepted, after a minor revision.

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 web dynamics at wetland shorelines/flood zones, and effect of management regimes on species abundance and distribution.

Today we submitted the first scientific paper in the project. It is 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).

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.

Peter has spent some 10 days in July in Halland to repeat the invertebrate sampling in the 50 selected wetlands that were investigated also last year. Focus was on Maialsie-traps. The photo shows the trap at the wetland ”TA25”

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.

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

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.