editorial the Dutch birding organisation is pleading for a more bird friendly Oostvaardersplassen. They specifically want room for the Eurasian Spoonbill and Eurasian Bittern. The reason why they are in decline are carp, mature carp. They eat anything including small fish and, they can live to be some eighty years old. There is no real predation on the carp.
There is only one predator that will have a significant impact when it finds its way into the Oostvaardersplassen; it is the Wels Catfish. A current proposal is to drain the Oostvaardersplassen regularly consequently most water animals will die and repeats will be "needed". When the Wels Catfish is introduced after a drainage, they will eat the maturing carp and ensure a more healthy age distribution in carp and make room for birds and other fish as well.
In this way we come to rely on ecological processes and realise a more complete (age) distribution of species. In the editorial they call for ecological connections so that animals can migrate for optimal results. Introducing such connections for fish as well would be of a huge benefit for the birds that predate on smaller fish. One of the fish that would find its way into the Oostvaardersplassen is the Three-Spined Stickleback. It serves birds like the European Spoonbill really well.
One other thing to consider; the Oostvaardersplassen was developed to support the goose, a bird that was rare at the start of the Oostvaardersplassen. When we make the ecosystem more complete, we will end up with a different environment, an environment that will be more diverse with more species finding their niche.