11. It is a pioneer species , growing on bare outcrops unoccupied by any other plants. 12. Plants such as rushes grow once the mud has been vegetated by the pioneer species . 13. It is a pioneer species sometimes used in revegetation efforts in riparian habitat in Brazil. 14. Ragweed ( and locusts ) are called pioneer species . 15. The plant is a pioneer species found in dry areas of California, Arizona, and Mexico. 16. The plantings have been mainly of hardy pioneer species best able to withstand the rigorous conditions. 17. Pioneer species are the first organisms that colonise an area, of which lithoseres are an example.18. "Cordyline australis " is a light-demanding pioneer species , and seedlings die when overtopped by other trees. 19. Today one comes across both pioneer species like European Rowans and different sorts of shrubs there. 20. It is a pioneer species in rough terrain.
