|Our Environment: Issue 14 Autumn 1998|
Rare Plants Found In Landfill
visits by botanist Colin Muerk and council staff to the Christchurch
landfill area near Bottle Lake Plantation have turned up several interesting
rare plants, including two species of sedge.
Waste Management has decided that the third stage site is not suitable for waste disposal because of its proximity to the coast. The area consists of an old sand dune system vegetated predominately with marram grass, scattered pine and grey willow.
It is now home to some significant rare plants including the sand-binding sedge Carex pumila growing in some old bulldozed tracks, and a large patch of Potentilla anserinoides silver weed, a delightfully soft, green plant with a distinctive silver underside to the leaf.
Carex pumila once grew abundantly in moist hollows in the sand dunes and sandy plains behind the northern portion of New Brighton beach, but is now rare due to dune modification and the invasion by more aggressive, introduced species such as marram grass.
While Colin Meurk was on his hands and knees taking a close look at the carex, he spotted the tiny sedge Schoenus constansus. This patch of Schoenus in the landfill area is one of only a couple of known sites of this plant in Canterbury. According to Colin Meurk, the dark oily green and orange-leaved plant growing to just 25mm would once have lived in the numerous wet hollows between sand dunes.
These new finds are in addition to the only known specimen on the Christchurch coast of the ground cover Gunnera dentata found a couple of years ago on a beach access track near Spencer Park. About the size of a dinner plate, this example is now fenced off for protection.
All these plants are now tenacious survivors of threatened species. The grey willows and pines invading their habitats need controlling. Parks Unit and Waste Management staff will co-operate to protect and manage these rare plants in the hope of increasing their distribution.
Carex pumila, sand sedge - note the nearby grey willow seedling invading the habitat.
Photo by Joe Cartman
|Our Environment Index|