Identifying animals and plants, restoring habitats https://berlin.nabu.de/
The Berlin senate helps to support a variety of projects – have a look: https://www.berlin.de/senuvk/natur_gruen/biologische_vielfalt/de/aktiv/index.shtml
Polically engaged in a wide variety of topics
Want to set up an Umwelt AG /climate club in school?
Here are some tips: https://www.schule-klima-wandel.de/
Useful films you can watch (in German)