After years of decline, there are signs of improvement in Dutch flora and fauna stocks, the national statistics office CBS said on Tuesday.

The strongest improvement is shown by dragonflies and mammals but there has been little change in the position of amphibians and butterflies, the CBS said. Researchers looked at 1,800 different plants and animals.

The recovery is partly due to environmental project measures introduced over the past decades. For example, air pollution has been drastically reduced and this has helped nature to recover in many places, the CBS said.

In addition, action has been taken to improve the country’s natural resources and encourage plants and birds to thrive.

Many animal and plant species in the Netherlands have declined drastically since 1950 but since 1995 the decline has been either halted or reversed, the CBS said.

Nevetheless, despite the improvements, one in three species in the Netherlands remains under threat.