Rodent-induced damage to pine plantations: a South African case study

Rodent-induced damage to trees is common to first-rotation pine plantations in Mpumalanga, South Africa. Surveys of rodents in a pine plantation in this area were performed, including 1 year during which significant damage was caused by these animals. Damage to trees occurred 4-5 years after planting, with tree mortality amounting to 8% of the total planting. The rodent assemblage structure in areas with damage did not differ from that in plantations with no rodent damage. Eight years after planting, rodents were confined to edges or to clearings within the plantations, with a significantly reduced relative abundance in plantations compared to grassland. Rodent abundance was correlated with changes in the assemblage structure of shrubs and grasses within the plantation: 5 years after planting, the natural grassland under trees was moribund, and the rodents turned to feed on the remaining pine trees. Eight years after planting, the ground cover was reduced to such a degree that a rodent population could not survive in the plantation. Habitat manipulation before planting may contribute towards minimising rodent damage to pine plantations in Mpumalanga.