Special features of urban natural areas

Natural areas in a city can be highly diverse, varying from nature almost in its original state to nature highly impacted by human activity.

People often favour early phases of natural growth, for example, uniform lawns. Various development phases may also be mixed in peculiar ways. For example, very old trees may grow on new lawns.

Green areas can be small and so isolated that their species have no connection with individuals of the same species in nearby areas. This makes it more difficult for the species to multiply and can weaken their genetic conditions. Ultimately small habitats and their species disappear.

Human activity is reflected in natural areas in many ways. For example, overgrowth of land caused by human activity can bias ecosystems, and species that thrive on nitrogen such as the nettle become more prevalent. Rare species become even more rare.

On the other hand, human activity has powerfully increased the variety of species. Helsinki still has species imported in the ballast of old sailing ships and other species imported by troops from Russia during Finland’s Russian era. As regards the built environment, biodiversity is highest in manor parks, although yards and gardens can also be highly biodiverse.

New species can have surprising impacts on ecosystems. Invasive species may prove to be harmful to established species and cause habitats to change. Harmful invasive species are avoided and controlled.

According to the Nature Conservation Act, invasive species must not be allowed to spread in nature if there is reason to suspect that they can become permanent species.

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06.12.2019 18:30