The amphibians pond near the school work gardens has been looking sad for some time now. Last year a large carp was caught from it, but since then the pond has never returned to good condition. There were still some frogs this spring, but most of the aquatic plants are gone, and the water looks grey and lifeless.
It was suspected that an invasion of American crayfish might be the cause. To determine that, the pond had to be pumped out.
Because this could not be properly arranged through the municipality, where only a small pump was available that would have to be used for two days, the idea was born to ask the fire brigade for assistance. They were willing to do this as a service to the local community and would also use it as a training opportunity for a group of aspiring volunteer firefighters. They had 2 large pumps at their disposal and arrived on site on Sunday 12 September with two large fire engines and a van for passenger transport.
The firefighters arrived earlier than announced, so when I arrived (well on time), they were already pumping, and the job was done within half an hour. But it still took a long time to rinse and clean the hoses, pumps and other equipment afterwards.
Meanwhile, a group of children, local residents, members of the Bijlmerweide nature working group and volunteers had gradually arrived, who would catch as many lobsters as possible with landing nets and sieves. Some of the men donned waders and ventured into the pond and among the reeds to search the banks and remaining water.
Quite a few crayfish were caught, about 130, but that number was not nearly enough to be the cause of the problems. Koen Wonders, biologist of Urban Ecology, was also present. He examined the water of 2 pools and the open water of the Bijlmerweide for acidity and salinity, but those values were completely normal and comparable, so no cause could be identified there either.
After all the activities and bustle around it, the pool can now slowly fill up again with seeping ground- and rainwater. The proposal is now to turn this into an internship project for 1 or 2 students, who would then study the further development of the pool in the coming year.
(Most of the info comes from Ruud Wolterman's emails to the Bijlmerweide nature working group - thank you for that - and from my conversations with Koen Wonders and one of the instructors of the Firebrigade)
It was suspected that an invasion of American crayfish might be the cause. To determine that, the pond had to be pumped out.
Because this could not be properly arranged through the municipality, where only a small pump was available that would have to be used for two days, the idea was born to ask the fire brigade for assistance. They were willing to do this as a service to the local community and would also use it as a training opportunity for a group of aspiring volunteer firefighters. They had 2 large pumps at their disposal and arrived on site on Sunday 12 September with two large fire engines and a van for passenger transport.
The firefighters arrived earlier than announced, so when I arrived (well on time), they were already pumping, and the job was done within half an hour. But it still took a long time to rinse and clean the hoses, pumps and other equipment afterwards.
Meanwhile, a group of children, local residents, members of the Bijlmerweide nature working group and volunteers had gradually arrived, who would catch as many lobsters as possible with landing nets and sieves. Some of the men donned waders and ventured into the pond and among the reeds to search the banks and remaining water.
Quite a few crayfish were caught, about 130, but that number was not nearly enough to be the cause of the problems. Koen Wonders, biologist of Urban Ecology, was also present. He examined the water of 2 pools and the open water of the Bijlmerweide for acidity and salinity, but those values were completely normal and comparable, so no cause could be identified there either.
After all the activities and bustle around it, the pool can now slowly fill up again with seeping ground- and rainwater. The proposal is now to turn this into an internship project for 1 or 2 students, who would then study the further development of the pool in the coming year.
(Most of the info comes from Ruud Wolterman's emails to the Bijlmerweide nature working group - thank you for that - and from my conversations with Koen Wonders and one of the instructors of the Firebrigade)
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