Most of Namibia's savanna rangelands, dry woodlands and Nama-Karoo shrublands are threatened by encroachment of indigenous woody species, which become denser and expand their range. Estimated at more than 30 million hectares of affected land, bush encroachment drastically reduces the grazing capacity of farmland, biodiversity, soil moisture content and groundwater recharge. Some ten indigenous tree species are declared as encroachers.