8 A healthy creek
The water in the Haaganpuro creek is clearer than before thanks to restoration work. The nature in and along the creek is rich and diverse in organisms.
Endangered sea trout rise up the creek here and onwards up the Maunulanpuro creek to spawn. The playful dipper dives in the water in wintertime to feed on the larvae of caddisflies and stoneflies.
The signs of a healthy and naturally diverse creek include a meandering stream bed, babbling clear water, shady trees along the banks, trees and branches in the water, a bed of gravel and sand, water mosses, benthic invertebrates, fish larvae, flying insects and the birds that feed on them. Which of these characteristics can you identify in this creek?
Impatiens glandulifera is an invasive plant species that grows along the creek in places. It spreads rapidly and claims territory from indigenous plants. The help of volunteers is needed remove any of these invasive plants they come across.
Natural streams and creeks help purify the water. Rapids and waterfalls aerate the water, which is very important for the fish in particular. Countless microorganisms also play a vital role in cleaning the water. They convert the leaves and other organic materials that fall into the water into food suitable for fish and larger animals.