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‘Smart life trap’ recognizes and catches first coypu on Dutch border

For the first time a coypu has been recognized and caught by a ‘smart life trap’, rigged with image-recognition on the Dutch-German border near Winterswijk. This animal species is not native to Europe and this new technology will help water authorities to catch them.

A ‘smart life trap’ uses image-recognition to recognize and trap animal species: the cage closes catching muskrats and coypu, while it remains open when entered by, for example, birds or otters. In January a coypu in the Wooldseveen moor near Winterswijk walked into the cage, was recognized and caught. It was the first catch in the field, after a long preliminary phase of testing and refining.

More efficiënt

Pest controller Jari Bremer: “With image-recognition in the cage we avoid unwanted by-catches and we are more efficient, we only catch animals that pose a risk. It’s great that we’re able to catch only the right animals, thanks to a camera and technique that keeps improving.” Bremer received a signal from the cage in Winterswijk on his smartphone and confirmed the catch in the field. He delivered ‘smart life traps’ in German project areas as part of the Life Mica project. This will happen in Belgium as well.

Risk to dikes and nature

Muskrat and coypu are alien species in the Netherlands. They have no natural enemies, they weaken banks and dikes and they interfere with inland species. In the past half century the muskrat population declined from half a million to less than 10%. In 2021, fewer than 45,000 muskrats were caught in the Netherlands. Hundreds of coypu are caught in the Netherlands along the border, but they are hardly found further inland.

Up to the border

The water authorities want to push back the muskrat up to the border alike. “Technical innovations will help”, says Pascal van der Linden, team leader pest management. Such as image-recognition, which now yielded the first catch. “This was preceded by a period in which we created an extensive image bank with all kinds of species, modeling and data analysis. For example, the camera has also been tested in a German otter center.”

50 traps

A total of 50 traps will be rigged with image-recognition based on AI software, supplied by Robor Electronics bv in Bentelo. The ‘smart life trap’ will further develop in the coming years. Muskrattenbeheer Rivierenland works on the Dutch-German border between Haaksbergen and Groesbeek, with a working area that extends over 4 water boards between the border and the sea: Rijn and IJssel, Vallei and Veluwe, Hollandse Delta and Rivierenland.

Does DNA mapping help to manage the influx?

One of the components of the Life MICA project is a study into the interrelationship of muskrats. This allows migration routes to be determined. In the period February 2020 – February 2021, muskrat trappers in the Netherlands, Belgium and Germany collected tail tips from muskrats for this research.

Central to the research is the muskrat population in the province of Friesland. Samples were collected in Friesland and in a surrounding area. As a reference, samples were also collected in Germany (Vechte), Flanders, Rivierenland and Tiengemeten.

Research questions

Three research questions have been formulated for the study:

  1. Can source areas be recognized through a difference in DNA profile?
  2. Is there reproduction within Friesland?
  3. Is there immigration from surrounding regions?

Source areas and Friesland

The results of the DNA analysis are plotted in the graph above. Each color represents a trapping organization. Red dots between yellow dots means that the muskrats trapped in Friesland show a strong relationship with the population in Zuiderzeeland, and especially the Noordoostpolder. The 3 free red dots on the right side represent the ‘own’ Frisian population.

Origin of muskrats trapped in Friesland

3% of the muskrats sampled come from the presumably ‘own’ population of Friesland. The distribution of the origin of the other sampled muskrats is:

  • 58% Noorderzijlvest
  • 26% WDO Delta
  • 13% Zuiderzeeland

The answers to the questions:

  1. Can source areas be recognized through a difference in DNA profile?
    Yes, the DNA method used can be used to tell the different source areas apart.
  2. Is there reproduction within Friesland?
    Yes, some animals have been found from the (presumably) original muskrat population in Friesland.
  3. Is there immigration from surrounding regions?
    Yes, except from North Holland, muskrats have been found from all surrounding areas.

What’s next?

Based on the results, the trap intensity along the probable inflow locations in Friesland will be increased by placing a cordon of traps here. In addition, in the period from February 2022 – February 2023, the tail tips of all muskrats trapped in Friesland will be collected for follow-up research.

Muskrats trapped in Friesland after positive eDNA sample

In August/September 2021, 3 muskrats were caught in Friesland thanks to eDNA. It concerned an area with a low muskrat population.

Tracking down muskrats and coypu can be made easier by detecting the DNA they leave behind in the water. This DNA is called environmental DNA (eDNA) and comes from, for example, intestinal cells in faeces.

Sampling

In this case, a 5 km section between the towns of Bolsward and Hartwerd turned out to be positive. Subsequently, 1 km sections were sampled, of which 1 was positive for muskrat eDNA. Afterwards point samples were taken.

Feed traces

During point sampling, the muskrat trappers found some questionable feed traces. These did not directly indicate a muskrat, but could also have come from a water vole. Thanks to the eDNA the muskrat trappers knew that muskrats had been present, so they so they carefully scanned the water’s edge. There was indeed a muskrat burrow. This is how the first muskrats of 2021 were trapped in this area.

Caught muskrats between Bolsward and Hartwerd

A. In red, positive 5 km route;
B. In red, positive 1 km localization section;
C. Localization point samples. Red: highest positive concentration, orange: moderate positive, green: negative. Arrow: location of the trapped muskrats. At the second red dot at the top, the water was too deep;
D. The trapped muskrats.

Latest progress in development Smart Life Trap: first catch

This project aims to develop smart life traps that use image-recognition. Thus we prevent unwanted bycatches of protected species as European beaver or otter and only catch target species like coypu and muskrat. Recently we made good progress on the Smart Life Trap project. The first catch was made in the field.

Image-recognition is dependent of many pictures; we received lots from the field. Thanks to people from the regional water authorities and volunteers from zoos as well.

New model

A new model was made and tested. Overall the new model already makes good predictions. The Artificial intelligence specialists made a model that is quite accurate. Below is a ‘confusion matrix’. It shows the number of accurate predictions: mainly correct ones. It predicts ‘Rat group’ when it is actually a ‘Rat group’ indeed and the same with birds and the ‘Others group’ category. However, it still made some incorrect analysis. This was improved in the last months of 2021, with new photos from the field.

Real life tests and results

Below are photos with a ‘heatmap’ overlay. The more yellow/red the image is, the more this part of the picture was used for recognition. We can see from the photos that it concentrates mainly on the actual animal even when other objects like leaves or food are in the picture as well. And recognition succeeds at night as well.

Many images

In the past months we also succeeded in entering many images of otters and beavers, with the help of a German otter centre (Otter-Zentrum Hankensbüttel) amongst others. This will make the model even more accurate, even when animals look like the target species but are different.

Camera

The camera was built into 5 traps and tested in different settings, day and night. The first actual catch in the field occurred in December: a muskrat. As a control set-up, we use 24h wild game camera’s to observe the test traps and the animals entering it.

50 Smart Life Traps

In the first months of 2022 a total of 50 Smart Life Traps will be deployed across national borders: Germany (20), Belgium (5) and the Netherlands (25).

Dragonflies and damselflies as indicators for biodiversity

The month of June was dominated by dragonflies and damselflies for the Life MICA employees of the Institute for Nature and Forest Research (INBO). An important part of the Life MICA project is monitoring biodiversity in the project areas.

This data can help to estimate the impact of muskrats, coypu and their impact on nature. In Flanders, birds, plants and dragonflies are monitored in the De Luysen nature reserves in Bree (Limburg) and in the East Flemish creek area in Sint-Laureins.

9 species of damselflies

The first monitoring on 2 June took place under ideal weather conditions in the Luysen. We immediately observed a large number of species along the transects. We saw 9 species of damselflies, including the variable damselfly, the white-legged damselfly, the common winter damselfly and the Large Redeye damselfly.

Dragonfly

It was also clearly the peak of the flight time of the glass cutter, which flies unobtrusively among the reeds. We also saw the brown corn bolt whose males are on the lookout for the reeds. In total we saw 7 species of large dragonflies in this swamp area, including the Blue Emperor dragonfly. On subsequent visits, we were able to add several more armored spread-winged damselflies to this list. We also saw large numbers of Ruddy Darter.

The dragonfly monitoring is over for this year. We are already looking forward to next year!

Raccoon detected with camera trap

It is clear that camera traps are useful for tracking muskrats and coypu. The Life MICA partners have already collected more than 2000 images of muskrats. More than 1000 coypu were also captured on image.

A nice advantage for the muskrat control is that other invasive species can also be seen on the camera images. A raccoon was spotted in the De Luysen area (Limburg, Flanders) in May. The raccoon is already widespread in Europe, but in Flanders the species is still on the rise and often remains under the radar.

Circulation of muskrats and coypu

Images like these can help to map the circulation of muskrats and coypu. They also can help with targeted management of the species.

Searching and catching in Sint-Laureins

The landscape of creeks and polders in the border municipality of Sint-Laureins houses the last large population of muskrats in East Flanders. It is important to continuously monitor this area to avoid expansion and to reduce the species.

In 2021, the Flemish Environment Agency (VMM) started its control campaign here with the spring migration of muskrats at freezing temperatures. These migratory muskrats are often difficult to catch.

324 muskrat catches

During summer traces are very different. Territories are marked and plenty of food remains can be seen. Six months of hard work, aided by observations of 10 camera traps, yielded 324 muskrat catches. 195 of these were captured within the contours of the Life MICA project area.

Next control campaign

As soon as the high summer levels in the polder drop again, the VMM is organizing a next control campaign in the area.

First virtual Open day at the project site Aschauteiche

Raising awareness on invasive alien species – a focus of MICA

The MICA project is dealing with the management of two invasive alien species, coypu and muskrat, and therefore intends to raise public awareness on this subject. During the course of the project, several communication events, such as open days, are organized. Due to the coronavirus pandemic, some of those public events had to be cancelled or postponed.

It was originally planned to welcome different stakeholders and interested public for open days in the 11 project areas (in Germany, the Netherlands and Belgium) in order to introduce them to local project activities, to discuss about the project progress and receive suggestions for improvements. However, facing ongoing restrictions for public events and considering the safety of the participants, we decided to set up our first open day for the project area Aschauteiche as online event using Microsoft teams.

The German project site Aschauteiche

The German project site Aschauteiche, close to Eschede in the municipality of Celle, is a sustainable fishpond cultivation comprising near-natural lakes. The project site is part of a FFH and EU-bird protection area and home to several protected species. About a decade ago, coypus established at the lakes and, recently, the fish otter settled there as well. At this site, the Life MICA project intends to assess the impact of coypus on biodiversity and to test intelligent live traps closing only for target species like coypus.

The first virtual open day at Aschauteiche

The event took place on July 2nd 2021, when stakeholders from the local nature conservation office, the mayor of Eschede, the hunters association, a nature conservation organization, the Otterzentrum Hankensbüttel, members of the Agricultural Chamber of Lower Saxony and interested public participated in the event.

After a general introduction to the Life MICA project, we presented a short film (in German) about our activities at the project site and the characteristics of the area.

Helge John, employee at the fishpond cultivation and member of the hunters association, offered an interesting insight into the history of the Aschauteiche and the local occurrence and management of coypu populations as well as protected bird species. Furthermore, we had a great guest contribution from Martin Brühne, project leader from Reeds-for-Life (www.lebendige-roehrichte.de), about coypu management in the nature conservation area Bienener Altrhein and the successful replantation of reed vegetation to recover the damage caused by coypu during the past years.

A total of 21 persons participated in the event and several topics ranging from live trapping to the impact of coypus on biodiversity were lively discussed. In general, the feedback from the participants was very positive, highlighting once again the importance of communicating with different stakeholders and related projects about the problematic of invasive alien species.

Outlook for 2022

In 2022, we hope to be able to welcome interested stakeholders in person at the project site!

Watch: Life MICA event of February 9, 2021

On February 9, the Life MICA project organized a webinar. This webinar looked back on the first year and a half of the project. What have we done so far and what have we learned from it?

Watch webinar

To log in, use the email address lifemica@wsrl.nl

Enjoy watching!

9 February: Webinar Life MICA

Life MICA is an EU Life project with the aim to reduce and manage muskrat and coypu populations in order to prevent damages to dikes, biodiversity and crops in Europe. Institutions from Belgium, Germany and the Netherlands work out a number of best practices and develop new techniques for a more efficient muskrat and coypu control.

The Life MICA project has now been running for 1.5 years. During this project we are assisted by a project board.

We would like to invite you to a varied online event on Tuesday 9 February at 10:00 hrs. During this event you will hear all about the knowledge we have gained, we will tell you where we are now and what to expect. There is plenty of room for questions and discussions. We are looking forward to meet you.

> Attend the webinar