Habitat Biodiversity & Pest Management Ltd

Preserving Our World

Proposal for Exotic Weed Control

at Arapaoanui 3E

Introduction Habitat BPM Ltd has recently completed a multi faceted restoration project at Arapaoanui 3E on the coast of Northern Hawke’s Bay. The land is owned and administered by the Arapaoanui 3E Trust and has a Nga Whenua Rahui Kawenata (covenant) over much of the land. The attached ’Map of Arapaoanui 3E’ shows the legal boundary of the block and the fenced area which encompasses most of the Nga Whenua Rahui area. However, the coastal cliff face was unable to be fenced due to contour and erosion processes but this area is part of the Nga Whenua Rahui. Arapaoanui 3E also has additional land that is being farmed as cropland outside of the Nga Whenua Rahui. This is labeled on the attached map as Figure 1. The project to date has involved erecting a goat-proof fence, removing feral goats and cattle from the block, designing and implementing a planting plan, wetland development and an ETS Assessment. Some exotic weed control was also carried out during planting preparation but this was limited by budget constraints. Several exotic weed species remain in the block and pose a threat to the future success of the native trees and shrubs which have been planted. Previously, these weeds have been suppressed by the feral goat population and cattle within the block. Now that these animals have been excluded from the block, weeds will grow uninhibited. Species such as pampas grass (Cortaderia selloana) and blackberry (Rubus fruticosus) grow quickly, are highly fecund and have the potential to rapidly expand their distribution and crowd out native trees and shrubs.

Coastal section of the new fence. The cliff face shown here is outside the fenced area but within the Nga Whenua Rahui area.

Pampas Grass Pampas grass is present at a moderate scale on the coastal cliff face of the block and to a lesser extent further inland. The cliff face is outside of the fenced area but is within the Nga Whenua Rahui Kawenata (Figure 2 on the attached map). These grasses are predominantly distributed on the lower slopes of the cliff faces meaning control now would be considerably easier and more cost effective than in a few years when their distribution has spread higher. The area atop the cliff has been planted with trees, shrubs and the native toetoe grass (Austroderia fulvida). Removing the pampas would prevent the species from establishing within the planted areas and potentially crowding out the slower growing native species. Native coastal plants such as Spinifex sericeus and Pimelea prostrata are also present on the boundary of the kawenata area. These are at risk of being crowded out by the pampas as it expands in range. Effective control would be achieved through a combination of slashing crown and backpack spraying with glyphosate at a concentration of 1L/100L.

Coastal cliff face of Arapaoanui 3E with pampas grass and wilding pines

Spinifex sericeus

Blackberry Blackberry is present throughout the block at various levels. In lowland areas, blackberry clumps are growing sporadically (Figure 3). Previously, this growth has been suppressed by feral goat and cattle grazing. This has mostly prevented large masses of blackberry forming but has failed to prevent the species from expanding it’s range. These clumps are growing between the newly planted trees and shrubs and threaten to crowd them out if left uncontrolled. This is particularly true of one valley basin (labeled as Figure 4) where blackberry is growing on the forest margin and reaching a significant height. These areas could be virtually cleared of blackberry through backpack spraying with Matrix at a rate of 35g/100L. On steeper hill faces which have been grazed less consistently, blackberry growth has amassed and covered relatively large tracts of land. This includes areas on the northern hill faces which were not able to be planted due to the dense blackberry cover (Figure 5). These areas would also be controlled through backpack spraying but may require a repeat dosage to clear patches which survive the initial control operation.

Typical clumps of blackberry which are growing sporadically through the lowland valley basins.

Wilding Pines Wilding pines (Pinus radiata) are also present in the block. These have self seeded from the large forestry blocks in the surrounding areas. Approximately 60 wilding pines of varying sizes have already been removed from amongst kanuka-manuka forest on the northern hill face of the block (Figure 6). Control has been through felling of smaller trees and ring-barking of larger trees. However, there is potentially a large number of smaller trees remaining through the rest of the block plus a few very large trees which will require stem poisoning via coring and control with Glyphosate.

Pricing Ground control $45 + GST per hour for ground/loose tool work (backpack spraying, wild pine removal) Blackberry control for northern hill faces = 32 hours Blackberry control for valleys and flat areas = 16 hours Control for cliff face - pampas and wilding pines = 16 hours Wilding pine control within fenced area = 8 hours Ground control = $3,240.00 Materials 1 x 1kg container of Matrix 1L of glyphosate Materials = $100.00 Travel 72c per km 90km per day 5 days travel 5 x 90km = 450 km Travel = $324.00

Total = $3,664.00 + GST

Preserving Our World