Question

how can we contribute to save natural vegetation

Answer 1

Do not plant or import non native plants. Pull up and destroy non-native plants. Do not carry plants, firewood, leaves, nuts, cones etc. from one area to another. This can introduce pests and disease. Do not use herbicides, insecticides, or fertilizer if possible. They can all cause unintended negative effects. Do not clear out wooded areas, the rotting leaves are part of a nutrient cycle. The most important thing, of which all the above is related to, is to introduce nothing and take away nothing from natural areas. Let them do their own thing.

Answer 2

Do not import native plants...
Do not use herbicides, fertilizer and insectisides
Do not clearout wooded areas.
Do not carry plants, firewood from one place to other