Very few remnants of dryland grey scrub in North Canterbury are protected on private land. This ecosystem type is also under-represented in the public conservation estate.
Understanding the significance of dryland shrublands and their management requirements is fundamental in encouraging landowners to both recognise and protect grey scrub sites.
Right: Dryland shrubland on Collessie in an arid part of North Canterbury.
On Collessie, David Anderson’s 1,053ha sheep and beef farm in the Lowry Peaks Range, a hilltop stand of dryland grey scrub is unusual in that two kowhai species are growing close together.
As a rule, either tree kowhai Sophora microphylla or prostrate kowhai S. prostrata is dominant.
The Collessie shrubland is exceptional with both species co-existing and equally abundant.
David protected two blocks of grey scrub with the 21ha Cameron’s Knee covenant in March 2009.
Above: This unusual shrubland containing both tree kowhai Sophora microphylla and prostrate kowhai S. prostrata is now protected in perpetuity with an open space covenant.
As well as protecting the kowhai, the covenant is habitat for the threatened Coprosma wallii and several species uncommon in the Waiau Ecological District including C. virescens, Melicope simplex, Scandia geniculata and Vittadinia australis.
Above: Coprosma wallii
Porcupine shrub Melicytus alpinus along with Melicytus aff. alpinus (“Blondin”) and Melicytus aff. alpinus (“Dark”) are also present.
Above: Melicytus aff. alpinus ("Blondin")
To safeguard the high biodiversity values, a fence protecting the northern 11ha block from grazing stock has been constructed with contributions from QEII, the Biodiversity Condition Fund, Environment Canterbury and the landowner.
‘The southern block is on steep rocky land and will remain unfenced in the meantime,’ says Miles Giller, QEII North Canterbury Regional Representative.
'This area has regenerated under a light grazing regime for over 150 years, a practice that is considered sustainable.
'Monitoring the two blocks will give us valuable insights on management regimes for dryland ecosystems.’
Above: Looking north along the western fence line towards the Lowry Peaks Range. Comparing the sustainability and succession of vegetation in the fenced block with the lightly grazed block will improve understanding of dryland ecosystem management.
With some steep terrain to take into account, a measured approach was taken to planning and constructing the fence.
‘I like doing a fence well the first time as this reduces maintenance later,’ says David.
‘Much of the line was bulldozed but we did use an existing bank in one area rather than forming a new track which would have left a scar.
‘Part of the line is on a vertical rock face and we had to blow some holes and dig others by hand. Doug Taylor was contracted to do the post driving and Les Exton who works on the farm did most of the construction.
‘I’ve been on the farm for 49 years and have always had a soft spot for this area,’ explains David.
‘Having the assistance of Miles Giller gave me the motivation to protect it with QEII.’
Above: David Anderson checks the new fence protecting one block of the covenant from grazing stock.
The fence consists of wooden posts with 7 wires and lightning droppers.
For more about the biodiversity of Cameron's Knee covenant download Dr Brian Molloy's report (PDF 42KB)
Above: The threatened Coprosma wallii (Declining) has light grey bark with a red inner layer, numerous dark green, shiny, small leaves and violet-black fruits.
C. wallii habitat tends to have rather fertile substrates with vegetation limited by frost, water logging or severe summer drought.
Photos: Miles Giller
Open SpaceTM Magazine No. 77, November 2009 © QEII National Trust