ACAP: COMMUNICATION AND EDUCATION Students Secure the Safe Migration of Amphibians in Leeuwarden By David Brouwer1, Remco Ploeg1, Tariq Stark2 & Koen van Lieshout1
T
he Potmarge is a small river meandering through the city of Leeuwarden, in the North of the Netherlands. A large proportion of this river is guided by small streaks of fairly natural riverbanks on both sides. Unfortunately, there is also a busy bicycle road, situated alongside the river, causing fragmentation of amphibian habitats. As a consequence, a large number of amphibians are killed while crossing the road during their migration from hibernation sites to breeding waters. However, as detrimental as this situation to the amphibian community is, it also provides a remarkable opportunity. The bicycle road is right in front of Van Hall Larenstein, University of Applied Sciences. Passionate students are given the opportunity to get involved in a road mitigation project (initiated by Carlijn Laurijssens and Tariq Stark) as a volunteer or member of the coordination team to learn essential research- and natural history skills, get experience with project management and help employ outreach programs for the local community. Five years down the road the project still exists and expands with each consecutive year, all thanks to the dedication of students, the municipality of Leeuwarden and VHL University of Applied Sciences.
2016, we a reached the wider public with our message about why amphibians and other animals are so important.
THE FINGERPRINT OF A NEWT
The students that were directly involved in the project learned a lot about amphibian ecology, behaviour and, of course, how to protect them. In addition, this year we started to explore certain scientific methods regarding capture-mark-recapture techniques. Identification of individuals was based on photographs of the unique belly patterns in individual Smooth Newts, providing us with a non-invasive method.
HELPING THE AMPHIBIANS CROSS THE ROAD
Every year in spring, when the amphibians are migrating to their breeding waters, the cycle road is fenced at both sides, preventing amphibians from crossing it by themselves (Fig. 1, 2). Subsequently, the amphibians are trapped in pitfalls that are emptied by students twice a day. This resulted in a safe passage for more than 3,000 amphibians in the past five years. The majority consists of Smooth Newts (Lissotriton vulgaris) but also decent numbers of Common Toads (Bufo bufo) are present. Just a small proportion consists of Grass Frogs (Rana temporaria), Marsh Frogs (Pelophylax ridibundus) and Edible Frogs (Pelophylax kl. esculentus) (Fig. 3). The Edible Frog is a hybrid between the Marsh- and Pool Frog (Pelophylax lessonae). The low numbers of Marsh- and Edible Frogs can probably be linked to their late period of activity. More importantly, they hibernate at the bottom of breeding sites and rarely need to cross roads or migrate great distances. In 2016, David Broek, David Brouwer and Remco Ploeg coordinated a team (with the support from Van Hall Larenstein lecturer Koen van Lieshout) of more than 20 enthusiastic students, all contributing to the success of this project. Thanks to them, 558 amphibians safely reached the other side of the road. Figure 3 depicts the numbers per species from 2012 to 2016. We observed a small early peak of activity in the last week of February 2016 due to some warm days. This only lasted for a few days however, because the temperatures dropped again in the first half of March. The vast majority of amphibians migrated in the second half of March and the first half of April when the temperatures were suitable again. Helping hundreds of amphibians to safely cross the road each year is of course a good thing on its own merits. However, the educational value of the whole project may be even more important. In Van Hall Larenstein, University of Applied Science; 2RAVON, Reptile, Amphibian and Fish Conservation in the Netherlands. 1
Fig. 1: Volunteers and the municipality of Leeuwarden set up the fencing. Photo: David Broek.
Fig. 2: From left to right: The Potmarge river, the fencing and the bicycle road. Photo: David Broek.
Fig. 3: The number of transferred amphibians per species during five years of the Potmarge amphibian road mitigation project.
62 | FrogLog 25 (1), Number 118 (February 2017)