Department of Conservation ranger Peter Russell (above right) has a vision - to turn 24-hectare Matiu/Somes Island in the middle of Wellington Harbour into a perfect native forest ecosystem, one that is a snapshot of local pre-human vegetation. The Lower Hutt Branch of Forest and Bird kick-started the process when they grew and planted more than 100,000 native plants on the island during the 1980s and 1990s. When they began planting the island was essentially a grass-covered farm, with a few native plants clinging to inaccessible cliffs. Today the plantings are thriving, but in their midst are native species that are out of their natural range, pohutukawa and karo, for instance, which are both northern North Island species. It is these interlopers, as well as more obvious exotic weeds such as boxthorn and barberry, that weed-buster Peter Russell has in his sights as he crawls across the island on his hands and knees. He gives Alison Ballance a tour of the island to share his thoughts on what plants constitute weeds, and why he believes it's important that neighbours on the adjacent mainland manage weeds to prevent them reaching the island. Part two of this story plays next week.