From Friends of Mangarakau website
"A translation of Mangarakau is  “plenty of sticks; a great many trees” and this site describes some of the work that is being done to restore the area to that description.
Mangarakau Swamp is a national treasure, a unique and special place. It is the largest remaining wetland in the Nelson/Marlborough region - almost as big as all the other freshwater swamps in Nelson put together.
The swamp has survived to this day because it has defied every attempt made in the last 150 years to drain it.  Mangarakau was considered by early European settlers as an impediment to the access they wanted to the goldfields, timber, flax beds and coal mines of the locality, and a source of little more than eels and mosquitoes. Unable to drain it, they had to work around it. A few traces remain of their endeavors and settlements, but the wetland remains in all its glory, one of only 10% of our wetlands that have survived in all of New Zealand.
The wetland covers about 350 hectares, of which half is owned by the Department of Conservation. The Native Forest Restoration Trust owns most of the balance and the swamp is currently managed by Friends of Mangarakau Inc. which was formed in 2003.
The mature forest that once covered the wetland was Kahikatea and Pukatea-dominant, with a wide array of understorey species. Only a remnant now remains along the western edge, and this will be extended by planting.