Appendix 5
Round the Mountain Cycle Trail – Oreti Valley and Mararoa Valley Route Options – Terrestrial Ecology Report Simon Beale, MWH New Zealand Ltd – September 2014
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Round the Mountain Cycle Trail Oreti Valley and Mararoa Valley Route Options Terrestrial Ecology Report
Prepared for Southland District Council SEPTEMBER 2014
Southland District Council Round the Mountain Cycle Trail Terrestrial Ecology Report
This document has been prepared for the benefit of Southland District Council. No liability is accepted by this company or any employee or sub-consultant of this company with respect to its use by any other person.
This disclaimer shall apply notwithstanding that the report may be made available to other persons for an application for permission or approval to fulfil a legal requirement.
QUALITY STATEMENT PROJECT MANAGER PROJECT TECHNICAL LEAD Claire Perkins Simon Beale
PREPARED BY
Simon Beale ………………………………...... 09/09/2014 CHECKED BY ………………………………...... 09/09/2014 Grant Kluyts REVIEWED BY
Kristy Hall …………… …………. 09/09/2014 APPROVED FOR ISSUE BY
Claire Perkins …………… 09/09/2014
QUEENSTOWN 134a Gorge Rd, Queenstown 9300 PO Box 649, Queenstown 9348 TEL +64 3 450 0890, FAX +64 3 450 0891
REVISION SCHEDULE
Rev Signature or Typed Name (documentation on file). Date Description No Prepared by Checked by Reviewed by Approved by
Status: Final September 2014 Project number: 80506020 Our ref: Terrestrial Ecology Report
Southland District Council Round the Mountain Cycle Trail Terrestrial Ecology Report
Southland District Council Round the Mountain Cycle Trail Oreti Valley and Mararoa Valley Route Options Terrestrial Ecology Report
CONTENTS
1 Introduction ...... 1 1.1 Project Background...... 1 1.2 Purpose and Scope of Report ...... 3 1.3 Report Structure ...... 3
2 Methodology ...... 4 2.1 Desktop Investigations ...... 4 2.2 Site Investigations ...... 4
3 Ecological Setting ...... 5 3.1 Climate ...... 5 3.2 Geology ...... 5 3.3 LENZ Classification...... 5 3.4 Vegetation and Habitats ...... 6
4 Existing Vegetation Types ...... 7 4.1 Oreti Valley Route Option ...... 7 4.1.1 Overview ...... 7 4.1.2 Section 1OV: Mt Nicholas Road to the Ashton Burn (Ashton Flat North) ...... 7 4.1.3 Section 2OV: Ashton Burn to Oreti River Crossing (Ashton Flat South) ...... 9 4.1.4 Section 3OV: Oreti River Crossing to Three Kings ...... 9 4.1.5 Three Kings to Consented Trail ...... 10 4.2 Mararoa Valley Route Option ...... 11 4.2.1 Overview ...... 11 4.2.2 Section 1MV: Mavora Lakes Road to Mararoa River ...... 11 4.2.3 Section 2MV: Mararoa River Margins ...... 12 4.3 Nationally Threatened Plants ...... 12
5 Fauna ...... 13 5.1 Avifauna ...... 13 5.2 Herpetofauna ...... 13 5.3 Bat Fauna ...... 14 5.4 Introduced Mammals ...... 14
6 Effects on Terrestrial Ecology ...... 15 6.1 Construction of Cycle Trail ...... 15 6.1.1 Grassland ...... 15
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Southland District Council Round the Mountain Cycle Trail Terrestrial Ecology Report
6.1.2 Copper Tussockland...... 15 6.1.3 Shrubland ...... 15 6.2.4 Oreti Riverbed ...... 16 6.2.5 Beech Forest ...... 16 6.2.6 Seepages and Streams ...... 17 6.2 Gravel Borrow Areas, Dump Sites and Machinery Storage Sites ...... 17 6.3 Operation of Cycle Trail ...... 18 6.3.1 Vegetation Management ...... 18 6.3.2 Human Intrusion ...... 18
7 Proposed Avoidance and Mitigation Measures ...... 19 7.1 Route Alignment ...... 19 7.2 Mitigating Effects of Construction ...... 19 7.2.1 Site Definition ...... 19 7.2.2 Earthworks ...... 20 7.2.3 Vegetation Clearance ...... 20 7.2.4 Vegetation Disposal...... 20 7.2.5 Timing of Riverbed Works ...... 21 7.2.6 Restoration of Areas Affected by Earthworks ...... 21 7.2.7 Noxious Weed Control ...... 21 7.2.8 Protection of Lizards ...... 21
8 Monitoring ...... 22
9 Conclusions ...... 23
References ...... 24
Appendix 1: Plant Species List
Appendix 2: Site Photographs
LIST OF FIGURES Figure 1-1 : Indicative Trail Options and Sections ...... 2
Figure 4-1 : Distribution of Broad Vegetation Types Routes and Study Sections ...... 8
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Southland District Council Round the Mountain Cycle Trail Terrestrial Ecology Report
1 Introduction
1.1 Project Background
The proposed Round the Mountain Cycle Trail connects Walter Peak Station to Kingston via Mossburn over a distance of approximately 180 km. The trail route follows the Mount Nicholas Road before heading down the Oreti Valley to Mossburn and then on to Lumsden and Kingston via an old railway line formation.
A hearing on the resource consent application for construction and operation of the trail was held before an Independent Commissioner in April 2012. Following the hearing, resource consent was granted for the trail with the exception of a section of the trail route adjacent to the Eyre Mountains Conservation Park between the Mount Nicholas Road and a proposed bridge crossing, the Oreti River downstream of Windy Point. The affected section of trail follows the true left bank of the River and is notated in the resource consent documentation and the terrestrial ecology report dated April 2011 as Route Option 5A.
On the basis of the Commissioner’s decision the trail proponent, the Southland District Council (SDC), embarked on investigations to determine the viability of using an alternative route in the Mararoa Valley (Option MV). This would initially extend through part of the Snowden Forest Conservation Area, then along the Mararoa River before linking to the consented section of trail via the Mavora Lakes Road and Centre Hill Road. During the early stages of the route investigations the SDC sought advice about the possible existence of a paper road alongside the Oreti River downstream of the Mount Nicholas Road Bridge. Investigations undertaken by LINZ established that a paper road does exist despite its absence from survey plans which was attributed to a historic cartographic error. The paper road was subsequently reinstated on the survey plans which show that it follows an existing 4WD track across the Ashton Flats, crossing the Oreti River just upstream of Trig 14191 and connecting with Crown bordering the true right bank of the Oreti River and fronting Centre Hill Station owned by Landcorp Farming Limited (Landcorp). The upper part of the paper road upstream of Trig 14191 follows the originally proposed Route Option 5A to a large degree.
With official sanction of the paper road and in view of the large Landcorp holding situated beyond the true right bank of the Oreti River, the SDC elected to investigate another Oreti Valley route between the Mt Nicholas Road and the consented section of trail on the true right side of the Oreti River downstream of a point opposite Trig 15027. This route would include a long suspension bridge over the Oreti River where the unformed legal road crossing exists upstream of Trig 14191. The Mavora Lakes/Centre Hill Road corridor is considered an alternative route option and forms part of the overall route investigations.
On the basis of these investigations covering a range of disciplines the SDC is seeking resource consent for the trail options in the Oreti (Option OV) and Mararoa Valleys (Option MV). The indicative routes of the trail options are displayed on Figure 1-1 on page 2 along the key place names that are referred to in this report.
For ease of reporting and in particular in describing the local ecology, the two trail options are divided into four and two study sections respectively on the basis of broad topographic features as follows:
Oreti Valley Option: Section 1OV: Mt Nicholas Road to the Ashton Burn (Ashton Flat North); Section 2OV: Ashton Burn to Upper Oreti River Crossing near Trig 14191 (Ashton Flat South); Section 3OV: Upper Oreti River Crossing to Three Kings; Section 4OV: Three Kings to start of consented trail.
Mararoa Valley Option: Section 1MV: Mavora Lakes Road to Mararoa River (Snowdon Forest Conservation Area); Section 2MV: Mararoa River Margins.
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N Mt Nicholas Road
Snowdon Forest Conservation Area 1MV 1OV 2MV
Ashton Burn Trig 14182 2OV
Mavora Lakes Road Trig 14191
3OV
Eyre Mountains Conservation Park
Three Kings
4OV
Windy Hill
Centre Hill Road
Trig 15027
Figure 1-1 : Indicative Trail Options and Sections
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1.2 Purpose and Scope of Report
This report provides an overview of the terrestrial ecology along the two route options, descriptions of vegetation and habitat types encountered along both options, the potential effects of the construction and operation of the cycle trail and outlines measures to avoid, mitigate or remedy adverse ecological effects.
This report incorporates sections from the ecological report prepared in April 2011 for continuity sake since part of the initial route section of the Oreti Valley option as the crossing of the Oreti River remains relatively unchanged. Discussions on the study methodology and ecological setting of this part of the Oreti catchment remain relevant.
1.3 Report Structure
The report is structured as follows:
Section 1 - Introduction including background to the project; Section 2 – Methodology in terms of the desktop and site investigations undertaken; Section 3 – The ecological setting of the route options; Section 4 - Description of vegetation types and patterns including commentaries on defined route sections; Section 5 – Description of local fauna, based primarily on desk top investigations and field observations; Section 6 - The ecological effects of the construction and operation of the cycle trail; Section 7 – Proposed avoidance and mitigation measures. These are described in general terms with respect to construction methodologies and rehabilitation; Section 8 - Monitoring measures recommended. Section 9 – Conclusions; References.
Appendices attached to this report are:
A list of plant species observed on site; Site photographs taken along the route options. These are demarcated according to each route section displayed on Figure 1-1.
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2 Methodology
2.1 Desktop Investigations
A review of literature was undertaken in advance of the field investigations. This involved a review of relevant scientific reports, the Conservation Management Strategy (CMS) for Southland-West Otago 1995, anecdotal information provided by Department of Conservation staff, Land Cover Database (LCDB3), Land Environments New Zealand (LENZ) and DOC, the NZ Herpetofauna Database as well as the Atlas of Bird Distribution in New Zealand.
Scientific literature relating to the botany of this part of the Oreti catchment was limited to a botanical report of the Ashton Flats, prepared by Brian Rance from the Department of Conservation.
Colour orthophoto images (flown in 2002/2003) sourced from the Land Information New Zealand (LINZ) website and Google Earth images were used in combination with the Land Cover Database (LCDB3) to assess the landforms and broad vegetation types along the cycle trail. Examination of these images and LCDB3 allowed landform features and broad vegetation and habitat types to be discerned within the respective reaches of the Oreti and Mararoa Valleys in advance of site investigations.
2.2 Site Investigations
A walk over survey of the Oreti Valley route was conducted on 14 and 15 July 2009 from the Mount Nicholas Road to as far as the Oreti River/Windley River confluence. A further site visit was conducted in 24 January 2011 examining part of the original Route 5A along the base of Lincoln Hill and at a crossing of the Oreti River downstream of Windy Hill. Recent site investigations were conducted on 5 and 12 June and 4 July 2014. These covered the boulderfield on the South Ashton Flat, the section of the Oreti Valley option between the Oreti River crossing and the start of the consented trail and the section of the alternative Mararoa Valley option between the Mavora Lakes Road and the Mararoa River. The section of the trail following the margins of the Mararoa River as far as the exit point to the Mavora Lakes Road was observed by helicopter.
During the surveys, which were conducted in the company of a SDC appointed project manager, the trail alignment was assessed and adjusted where necessary in accordance with engineering requirements and to avoid sensitive ecological sites.
Vegetation and habitat types as well as sightings of native birds or calls heard were recorded.
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3 Ecological Setting
The section of the proposed Oreti Valley route option that extends across the Ashton Flats lies within the Mavora Ecological Region and Eyre Ecological Districts. The valley borders the Eyre Mountains/Taka Ra Haka Conservation Park. Part of the Oreti route downstream of the Oreti River crossing and the Mararoa Valley route option lies within the Livingstone Ecological District and border the Snowdon Forest Conservation Area. Snowdon Forest contains extensive areas of mountain, silver and red beech forest and is part of the South West New Zealand World Heritage Area.
3.1 Climate
Both trail route options lie within the montane climatic zone with exit points off the Mt Nicholas Road and Mavora Lakes Road situated at approximately 600 metres a.s.l. The Oreti River trail option gradually drops over a distance of approximately 35 kilometres to 400 metres a.s.l at the start of the consented section of trail. A rainfall gradient exists along the trails with rainfall steadily decreasing down valley reflecting the prevailing westerly airstream and orographic effect of the Livingstone Mountains to the west.
The broad vegetation patterns in both the Oreti and Mararoa valleys reflect the rainfall gradient and previous human induced disturbances. More subtle patterns reflect more localised factors such as drainage patterns and underlying geological and soil conditions.
3.2 Geology
A review of the 1:250,000 series geological map of the Wakatipu area shows that upper Oreti and Mararoa River valleys contain post glacial floodplains comprising of gravels, sands and minor peats. Landforms associated with these floodplains include outwash fans, colluvial fans, river terraces and intervening terrace rises. The aerial photos and Google Earth images shows that the lower hill slopes including the toe slopes which are traversed in short sections by the trail routes are underlain by a variety of parent materials including graded volcaniclastic sandstones and mudstones, serpentine and volcanic breccias with minor components of siltstone and mudstone. Distinctive geological features along the trail include the Moonlight Fault that follows the Oreti River from the base of Lincoln Hill north across the Ashton Flats and the rock outcrops that occur alongside the riverbed and in places border some of the older river terraces. The most notable of these outcrops is Three Kings which consist of sound lithologies that are possibly derived from greywacke or volcanic parent material (Royden Thomson, pers comm.).
The soils associated with the floodplains are recent soils of the Tasman and Mataura series which, the Topoclimate Southland soil information sheets describe, as “typically free draining, with the occasional depression areas with imperfect drainage”. The soils of the adjacent hill country are upland yellow brown earths of the Taringatura and Blackridge series. These are described as well drained with a shallow rooting depth that is limited by the gravelliness and bedrock that commonly occurs with 45 cm depth.
3.3 LENZ Classification
The Level III Land Environments of New Zealand (LENZ) classifies the floodplains of the lower and mid reaches of the Oreti and Mararoa Rivers as L1.1 which are subject to a cold climate with low solar radiation and low annual water deficits. Parent materials are alluvial sands and gravels predominantly derived from greywacke but also from schist, basic volcanic rocks and loess. The recent, well-drained soils are free draining and of high natural fertility. In a national context L1.1 is an acutely threatened environment as less than 3% of the land area within this land environment remains under indigenous cover.
The lower hillslopes surrounding the valley floors are classified as land environments Q2.1 and Q4.1.These are described as rolling hills with low solar radiations and very low monthly water deficits.
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Parent materials include greywacke and schist with extensive areas of alluvium and loess and scattered areas of andesite and basalt. Soils are moderate to well drained and of moderate fertility.
The other land environment traversed by the trail routes is O1.4 which cover the Ashton Flats and part of the terrace adjacent to the Mavora Lakes Road toward the Mt Nicholas Road junction. O1.4 is described as undulating river terraces and plains with high monthly water balance ratios, parent material dominated by alluvium and gravels overlain by soils that are well drained and of low to moderate fertility.
3.4 Vegetation and Habitats
In pre-human times the vegetation below the tree line along the upper parts of the Oreti and Mararoa catchments would have been dominated by mountain beech forest along with patches of copper and short tussocklands associated with wetlands and frost pockets. Following the arrival of Maori, fire became a major influence on the forest vegetation and with the onset of European settlement, fire was used with more frequency for pastoral development. These disturbances lead to a fragmented forest cover and increased extent of tussockland, scrub and shrubland that are apparent in these valleys today. Across the valley floors and river terraces, the influence of burning, grazing and oversowing/topdressing has resulted in loss of indigenous grass species at the expense of exotic pasture species. The influence of fire is especially evident on the hillslopes bordering the Oreti River from Trig 14191 through to the Windley River which features a mosaic of forest, scrub, shrubland and grassland vegetation as shown on Figure 4-1 on page 8.
The Three Kings and rocky outcrops that abut the river downstream of Three Kings support assemblages of flora adapted to the rocky substrates. These outcrops are also likely to contain a range of habitats for certain skink species and invertebrate fauna as well providing nesting sites for the nationally threatened NZ Falcon.
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4 Existing Vegetation Types
4.1 Oreti Valley Route Option
4.1.1 Overview
The Oreti Valley route option initially follows the paper road (along the alignment of an existing 4WD track) across the Ashton Flats from the Mt Nicholas Road. The Ashton Flats encompass an expansive area of modified short tussockland that is contiguous with the modified grassland that occupies the wide valley floor of the upper Oreti Valley and upper Von Valley to the north. The route crosses the Oreti River near Trig 14191 at the northern margins of an expansive area of mountain beech forest. Beyond the crossing the route follows the river margins of the Landcorp farm to the Three Kings traversing the edges of paddocks of improved pasture and extensive areas of tall exotic grassland on adjacent lower river terraces. Pockets of grey shrubland donated by matagouri and mingimingi exist along the low terrace risers that form the riverside boundary to paddocks of improved pasture.
From Three Kings the trail traverses varying topography and improved and unimproved pasture interspersed with distinct patches of mountain beech forest and grey shrubland generally encountered on the steeper rockier terrain. The trail crosses extensive areas of floodplain covered in unimproved pasture, areas of tall exotic grassland and extensive areas of copper tussockland.
4.1.2 Section 1OV: Mt Nicholas Road to the Ashton Burn (Ashton Flat North)
This section of the trail follows a 4WD track that extends across an expansive terrace covered for the most part in modified fescue tussock grassland, reflecting previous pastoral use of the flats. The cover of fescue tussock (Festuca novae-zelandiae) varies considerably along the route, occurring often as scattered tussocks amongst extensive swards of exotic grasses consisting of mainly browntop and sweet vernal. The density of fescue tussock tends to increase in abundance towards the Ashton Burn where drier ground conditions prevail. The ground between the tussock and exotic grass swards tends to be dominated by extensive mats of the light green moss Racomitrium languinosum along with rosettes of mouse ear hawkweed (Pilosella officinarum), cushions of turf mat dairy Raoulia subsericea, and in patches blue tussock (Poa colensoi).
Other conspicuous inter-tussock plants include catsear (Hypochaeris radicata*), Californian thistle (Cirsium arvense), snowberry (Gaultheria depressa var. novae-zelandiae) and the low growing sub- shrubs Pimelea oreophila and dwarf mingimingi (Leucopogon fraserii).
Large areas of bare ground are a feature of this terrace especially at its northern end demonstrating the shallow and erodible nature of the terrace soils and exposure to strong winds, especially from the northerly quarter.
Very scattered shrubs of bog pine (Halocarpus bidwillii), mountain cottonwood (Ozothamnus vauvilliersii) and Acrothamnus colensoi as well as scattered clumps of snow tussock (Chionochloa rigida) occur across the fescue tussockland.
At various points where the 4WD track crosses small streams draining the terrace to the north of the track, narrow bans of wetland vegetation fringe these streams and feature turfs of the bright green moss (Drepanocladus sp.), tufts of Juncus novae-zelandiae, loose dark tufts of Juncus articulatus and taller clumps of Juncus effuses. Carex sinclarii is prevalent especially across the wider boggier crossings.
Further to the south towards the Ashton Burn the track skirts several large wetland complexes. These contain areas of open water and large areas of sedgeland and smaller localised areas of rushland. The sedgeland contains a diversity of species with the most dominant being tussocks of Carex virgata along the extensive tufts of Carex coriacea and Carex sinclarii. Dark patches of the jointed rush Juncus articulatus are scattered amongst the sedgeland.
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Mount Nicholas Road
Modified Fescue Tussockland Mararoa River
Ashton Flats North
Valley Floor Wetlands
Mountain Beech Forest Ashton Flats South Upper Oreti Hut
Boulderfield Oreti River Crossing Trig 14191
Improved Pasture
Lincoln Hill
Matagouri - Coprosma Three Kings shrubland
Windy Hill
Start of Modified consented section of Fescue Tussockland cycle trail
Copper Tussockland
Windley River
Figure 4-1 : Distribution of Broad Vegetation Types Routes and Study Sections
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Shallower areas of water contain the spike sedge (Eleocharis acuta). The bright green clumps of rushes that are scattered throughout the sedgeland consist of two species, Juncus effusus and Juncus gregiflorus. Sorrell and Yorkshire fog are common adventive plants around the edges of the wetlands.
At the Ashton Burn a narrow band of snow tussock line the banks along with the occasional speargrass Aciphylla glaucescens and shrubs of the native broom (Carmichaelia virgata) and mountain cottonwood as well as patches of silver tussock (Poa cita).
4.1.3 Section 2OV: Ashton Burn to Oreti River Crossing (Ashton Flat South)
The trail route between the Ashton Burn and the Oreti River crossing traverses a range of vegetation types reflecting the more variable terrain and ground moisture conditions. While exotic grassland-fescue tussockland covers much of the drier elevated terraces and colluvial fans, there are numerous areas of sedgeland along the route associated with seepage zones at the toe slopes and associated with the margins of side streams. These sedgelands support a variety of herbaceous species and dwarf shrubs.
The sedgelands are generally dominated by Carex coriacea with herbaceous species such as Hydrocotyle sulcata, Aceana anserinifolia, Maori onion (Bulbinella angustifolia) while the small fern Blechnum penna-marina is numerous amongst the sedge tufts. The sedgelands associated with the more boggy sites are punctuated by clumps of mainly Juncus effusus.
Ground devoid of fescue tussocks and dense exotic grass swards across the drier terraces and fans is colonised by sub-shrubs such as Pimelia oreophila, Leucopogon fraserii and Gaultheria depressa var. novae-zealandiae, cushions of Raoulia subsericea, herbs such as the adventive mouse ear hawkweed Pilosella officarum, Ranunculus lappaceous, Gnaphalium audax, Celmisia gracilenta and catsear, the clubmoss Lycopodium fastigiatum as well as the mosses Rhacomitrium lanuginosum and Hypnum cupressiforme. The straggling sub-shrub Pernettya macrostigma is also common in these areas but occurs in boggy areas as well.
The lower lying land beyond the edge of the toe slopes and fans, particularly to the south of the Upper Oreti hut consists of a large wetland complex. This wetland features a mosaic of sedgeland types as well as rushlands which tend to occur as discrete clumps while patches of copper tussockland occur on the slightly more elevated ground.
The dominant shrub along the trail route is matagouri (Discaria toumatou) which is scattered in small and large patches across many of the terraces, fans and lower hill slopes. Many of the matagouri shrubs are covered in Old Man’s Beard lichen. Occasional shrubs of Copromsa cheesemanii, Coprosma rigida and koromiko (Hebe salicifolia) are encountered along the banks of some of the side streams while the shrub Leucopogon colensoi, the creeping pohuehue (Muehlenbeckia axillaris) and bracken are scattered amongst the fescue tussockland and some of the more open matagouri stands on the drier sites.
The greatest concentration of shrubland occurs in association with a large boulderfield downstream of the wetlands. This mixed shrubland contains a diverse array of shrubs which apart from the dominant matagouri and mingimingi (Coprosma propinqua) cover, includes Olearia bullata, Hebe odora, Hebe salicifolia, Coprosma tayloriae, Coprosma rigida, Aristotelia fruticosa, Melicytus alpina, stunted trees of mountain beech and the occasional mountain ribbonwood (Hoheria lyalli).
4.1.4 Section 3OV: Oreti River Crossing to Three Kings
From the Oreti River bridge crossing to Three Kings the trail for the most part traverses low (recent) river terraces on the true right side of the Oreti valley. The route passes in front of a Landcorp farm containing large paddocks of improved pasture.
The route initially heads across the floodplain of the river from the bridge crossing. The floodplain is covered in tall exotic grassland dominated by Chewings fescue, cocksfoot, browntop and numerous flowering heads of Californian thistles. Abutting the floodplain here are steep hillslopes featuring screes and a discrete shrubland dominated by Coprosma rigida with the occasional shrubs of Coprosma
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virescens. Some of the shrubs are covered in vines of the bush lawyer Rubus schmidelioides. The route bypasses the scree slopes linking with an existing farm track on a slightly elevated terrace. From this point the trail generally follows fencelines that form the riverside boundary to the Landcorp farm, alternating between areas of improved and unimproved pasture.
The route passes through an isolated area of mountain beech forest situated on the valley floor approximately two kilometres downstream of the bridge. The forest consists of mature trees with a canopy height of around 20 metres with discrete groups of younger trees, including pole stands and thickets of beech saplings where canopy gaps exist. Apart from young beech trees and saplings the sub- canopy woody vegetation comprises the occasional shrubs of Coprosma colensoi and herbaceous forest floor plants featuring prickly shield fern (Polystichum vestitum). Sedges such as hook grasses occur in the vicinity of a spring fed stream that flows through the forest.
Beyond the forest the route follows the edge of the Landcorp farm passing through improved and unimproved pasture, and tall exotic grassland, the latter generally associated with the floodplain. Extensive areas of sedgeland occur along the floodplain channels and around areas of standing water. The drier or more elevated areas of the floodplain feature a cover of exotic grasses and short tussockland (Fescue novae-zelandiae). In places the route crosses low terrace risers that mark the transition between the flood plain and slightly elevated terraces where the farm is situated. Patches of grey shrubland dominated by matagouri of varying age and density are encountered on the terrace rises. Pasture grasses generally exist beneath the shrubland cover. Rushlands and some sedgeland exist beside the numerous seepages that exist along the toe of the terrace risers.
Near to Three Kings the route climbs from the valley floor through a series of wide switch backs through extensive areas grey shrubland dominated by matagouri with mingimingi a sub-dominant components and intervening areas of semi-improved (oversown) pasture. The route levels off near a rocky promontory situated at the end of a spur that ends abruptly above the Oreti River. A shelter and toilet will be established beside a patch of young mountain beech forest by the promontory overlooking the Three Kings rock formation. The vegetation cover here is a more diverse shrubland community reflecting a variety of micro habitats afforded by the rocky terrain. Resident plants include matagouri, mingimingi, Corokia cotoneaster, Coprosma rugosa, porcupine scrub, the shrubby wineberry Aristotelia fruticosa, along with the occasional stunted Halls totara (Podocarpus hallii), mountain cottonwood (Ozothamnus vauvilliersii), the distinctive scrambling shrub Helichrysum selago, the golden spaniard (Aciphylla aurea) and Gaultheria antipoda. Blue and silver tussock is common on some of the broader sunnier sites amongst the shrubs.
4.1.5 Three Kings to Consented Trail
This section of the route traverses, climbs and descends around a series of steep hillslopes, gullies and rocky outcrops and across several floodplains to consented trail which commences near a rocky outcrop situated near the Oreti River.
From the rocky outcrop the route traverses around the top of an extensive area of shrubland dominated by mingimingi which covers steep slopes separating improved pasture from a narrow floodplain situated adjacent to the Oreti River. The shrubland merges with a remnant of mountain beech forest occupying similarly steep terrain. The route descends through the forest by switch backs to a low terrace slightly elevated about the river flood plain. The forest canopy consists of mature trees with moderate canopy closure. Beneath the canopy the understory vegetation is generally sparse except where canopy gaps or seepages occur.
Beyond the beech forest the route extends across the low terrace before gradually climbing in wide sweeps across the side of a hill and around a shallow side gully to another rocky knoll mostly across areas of improved pasture and sparse shrubland of young matagouri. Beyond the knoll the steep slopes overlooking the river are covered in shrubland dominated by matagouri and mingimingi with Coprosma rugosa and Coprosma tayloriae, cottonwood and kohuhu also present. The bush lawyer Rubus schmidelioides is commonly entwined in the canopies of a number of shrubs. In places bracken is co- dominant adding to the texture, pattern and colour of the scrub. Other characteristic species around the
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edges include koromiko, tutu (Coraria sarmentosa) and the speargrass Aciphylla glaucescens. Prickly shield fern (Polystichum vesticum) forms a patchy ground cover where the overhead shrubland cover is more extensive. The route follows the upper edge of the shrubland as it tracks south before gradually descending again through the shrubland to maintain a low gradient towards a small area of mountain beech forest associated with a rocky outcrop. Beyond the forest the route consists of a series of switchbacks in order to descend to a low terrace of improved pasture and then across an extensive area of tall exotic grassland to a rocky knoll covered in scrub near the Centre Hill Station homestead.
Thereafter the route enters a wide floodplain over a distance of approximately 3 km to the start of the consent section of the trail. The drier gravelly parts of the floodplain are typically dominated by tall swards of exotic grasses such as cocksfoot, Chewings fescue and browntop with herbaceous plants like Californian thistle and red clover locally dominant. The edges of numerous rivulets and channels that criss-cross the floodpain and other areas where drainage is impeded are colonised by sedgelands dominated by Carex coriacea and Carex sinclarii along with the occasional Carex virgata, clumps of Juncus gregiflorus, small loose groups of the twiggy shrubs of Olearia virgata var. virgata and the occasional toetoe (Cortaderia richardii) plus swards of Yorkshire fog and patches of Lotus pedunculata*. Towards the start of the consented trail the route passes through an extensive area of copper tussockland considered to be in good condition by virtue of the density and stature of the tussocks.
4.2 Mararoa Valley Route Option
4.2.1 Overview
The Mararoa Valley route option initially follows a 4WD track that provides access to the Red Stag Lodge from the Mavora Lakes Road over undulating terrain of modified short tussockland. Beyond the lodge the route follows the edge of mountain beech forest and then extends through the forest for a short distance before exiting onto a series of elevated river terraces in improved pasture located within a Landcorp farm. The route then descends to lower river terraces bordering the Mararoa River generally following fencelines defining the riverside boundary of a Landcorp farm (Haycocks Station) beyond which areas of tall exotic grassland and matagouri shrubland prevail.
The route joins Mavora Lakes Road near Trig 14182 following the margins of Mavora Lakes Road and Centre Hill Road and then along a short section of farm track to the start of the consented section of the trail.
4.2.2 Section 1MV: Mavora Lakes Road to Mararoa River
This section of the trail follows a 4WD track that extends across undulating terrain associated with the moraine deposits. The vegetation cover in this area is modified short tussockland surrounded by mountain beech forest. The grassland contains extensive swards of browntop and sweet vernal and scattered tussocks of snow tussock (Chionichoa rigida) and contrasting bright green circular bushes of the whipcord hebe (Hebe propinqua), the latter a distinctive feature of this grassland. The ground between the tussock and exotic grass swards tends to be dominated by extensive mats of the light green moss Racomitrium languinosum along with rosettes of mouse ear hawkweed (Hieracium pilosella), patches blue tussock (Poa colensoi) and the sub shrubs Gaultheria depressa var. novae-zelandiae and Pernettya macrostigma.
The route follows the edge of mountain beech forest by a fenceline for a short distance beyond the Red Stag Lodge. The route skirts a peat bog dominated by combe sedge (Oreobolus pectinatus) and other low stature sedges and mosses and then passes through a section of mature beech forest on mostly flat to undulating terrain before dropping diagonally across a terrace riser and exiting from the forest onto Haycocks Station. The forest interior along the route consists of mature mountain beech trees and the occasional large specimens of silver beech. The interior consists of discrete groups of younger beech trees, including pole stands and thickets of beech saplings where canopy gaps exist. Apart from young beech trees and saplings the sub-canopy woody vegetation comprises the occasional shrubs of
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mingimingi near the forest edge. The forest floor is dominated by mats of the bright green moss, Dicranoloma spp.
4.2.3 Section 2MV: Mararoa River Margins
The trail route follows the margins of the Mararoa River generally alongside a fenceline that forms the riverside boundary of the Landcorp farm. Although the inspection of this section of the route was conducted by helicopter, the vegetation types along the trail route were easy to discern from the air. Much of the route extends along riparian margins dominated by unimproved pasture and sward of tall exotic grasses and in places scattered matagouri and mingimingi shrubs. In places more extensive and continuous areas of shrubland occur which include the occasional bog pine (Halocarpus bidwillii). More extensive areas of grey shrubland dominated by matagouri and mingimingi occur on the landward side of the fence within the Landcorp farm. Several distinct areas of copper tussock exist near the river banks.
4.3 Nationally Threatened Plants
No nationally threatened plants were observed during the site inspections along the Oreti Valley route option or along the initial section of Mararoa Valley option within the Snowdon Forest Conservation Area.
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5 Fauna
The trail traverses across a variety of vegetation and habitat types as previously described, including open and tall grassland, forest, scrub/shrubland, wetlands, boulderfields, screes and braided riverbed. Of particular note are the numerous transitions or ecotones that exist between beech forest/grassland, beech forest/scrub and scrub/wetland (sedgeland) which more frequently occur downstream of Three Kings. These are particularly important for indigenous fauna, such as insectivorous birds, lizards and mobile invertebrates that can exploit a greater variety of habitat over a short distances and where enhanced hunting opportunities occur.
5.1 Avifauna
During the various site inspections a small number of birds were observed across the tussocklands and in and around the forest and scrub margins. These included a pair of Paradise Ducks near the Ashton Burn, a solitary black shag and oystercatcher in flight near the Three Kings and the nationally threatened New Zealand Falcon observed at two locations; flying at a low level over the shrubland upstream of Three Kings and attacking a Harrier hawk near a rock outcrop. It is likely that the rock outcrops that occur along this stretch of the Oreti River including Three Kings provide suitable nesting habitat for falcon. The threatened riflemen was heard on the mountain beech forest behind the Upper Oreti Hut and a male tomtit was observed within a matagouri/Coprosma shrubland near the boulderfield on South Aston Flat. Bellbird and grey warbler were heard in a patch of beech forest and scrub within a small gully downstream of Three Kings. During the site visit in January 2011 several black fronted terns were observed feeding above the flow channel immediately downstream of Three Kings. Blackbirds, chaffinches and yellowhammers were observed occasionally near the Upper Oreti Hut and around scrub margins between the Three Kings and Windy Point. A small group of magpies and a solitary grey-faced heron were observed flying across the riverbed near Windy Hill.
The beech forest remnants along the initial part of the Mararoa route and along parts of the Oreti Valley route contain large cavity-bearing mountain and silver beech trees in proximity to the trail routes that could provide suitable nesting habits for nationally threatened species such as kaka, yellowhead and yellow crowned parakeet as well as long tailed bats. Maps of bird distribution contained in the NZ Atlas of Bird Distribution (1999-2004) shows no records of kaka or yellow crowned parakeet in the forests of Oreti catchment, however both species have been observed near South Mavora Lake. The map of yellowhead distribution records observations in the lower Windley catchment. The atlas maps indicate that other native passerines not observed on-site such as brown creeper, fantail, silvereye, tui and long tailed cuckoo as well as the NZ Pigeon and morepork inhabit the beech forests and shrublands in the Oreti and Mararoa Valleys. The Atlas also indicates that aquatic birds likely to breed on the riverbed adjacent to the trail include the nationally threatened black-fronted tern, black-billed gull and South Island Oystercatcher. The breeding generally extends from early/mid September through to early/mid January.
5.2 Herpetofauna
A review of the DOC and NZ Herpetological Society websites indicates that at least four species of skink and two species of gecko are likely to be found in the mid to upper reaches of the Oreti and Mararoa catchments. These are the Otago Large gecko, jewelled gecko, common skink, cryptic skink, green skink, and McCanns skink.
According to the NZ Herpetological society website the Otago Large gecko inhabits creviced rock tors, outcrops and screes, lowland shrubland, and native forest and the jewelled gecko shrubland and forest.
With respect to skink habitats the website records these as follows:
common skink occupies a very wide range of generally open habitats up to 1800m including grasslands, shrublands, rocky sites and herbfields;
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Cryptic skink occupies tussock grasslands, herbfields, scrubland and wetlands, and also rocky areas such as scree, green skink occupies grassland or tussocklands, scrublands, herbfields and wetlands; and McCanns skink occurs in open habitats, usually occupying dry, rocky environments, grasslands, herbfields, scrubland, rocky tors, screes and is especially abundant in montane grasslands.
5.3 Bat Fauna
The forested section of the Snowdon Forest Conservation Area traversed by the Mararoa Valley route passes through mountain beech forest where mature mountain beech trees and the occasional silver beech tree exist. The larger trees may contain cavities that provide suitable maternity roosts for the nationally threatened long tailed bat. Large cavity forming trees are also encountered in the mountain beech forest remnants encountered along the Oreti Valley route.
5.4 Introduced Mammals
Signs of introduced mammals were evident along the majority of the trail. Pig rootings were observed as far up valley as the boulderfield on South Ashton Flat and were seen at regular intervals through to the Windy Point often around the margins of scrubland. Possum scats were seen on a number of occasions within the forested sections and across the modified fescue tussocklands. Hare numbers appear to be low with droppings observed infrequently. Other mammals known to reside in both valleys include red deer, ferrets, stoats, feral cats, hedgehogs, Norway and ship rats and mice.
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6 Effects on Terrestrial Ecology
6.1 Construction of Cycle Trail
The trail will typically be constructed to a width of 3.4 metres, comprising a 2.8 metre wide running surface and 300 mm wide water tables. The trail will be formed to a vertical gradient of no more than 3 degrees which is a Ministry of Business, Innovation and Employment specification.
Across the flat to gentle terrain such as the river terraces construction will typically involve the removal of a 3.4 metre wide turf layer and underlying soil down to a depth of 200mm using a small bulldozer. A small digger will be used to form the water tables. Gravel will be placed along the trail and compacted to form the running surface. The shoulders will be graded at a batter of 2:1. On the hilly terrain the cut batters may extend up to 2 metres above the trail.
A 3 to 5 tonne excavator will be used to construct the trail across steeper terrain and within the forested sections.
The scale of effects of trail construction will be influenced by terrain, vegetation cover, degree of wetness and hence drainage measures required, trail surface specifications and construction methodology adopted.
The following sections outline the construction methodologies required for each of the vegetation types and potential effects.
6.1.1 Grassland
Large sections of trail cross areas of grassland such as fescue tussockland, tall exotic grassland associated with the lower river terraces and floodplains and improved and unimproved pasture generally occurring within the Landcorp farm.
The formation of the trail will initially involve the removal of a turf consisting of short (fescue) and blue tussock, exotic grasses and inter-tussock plants such as sub-shrubs, herbs and mosses. The uplifted turf and plants will be stockpiled for later disposal off-site.
The effects of removal of this vegetation from along the trial corridor is considered to be no more than minor as the affected vegetation is predominately exotic or comprises commonly occurring indigenous plant species. The extent of indigenous grassland disturbed is generally limited to patches of short tussockland and inter-tussock sub-shrubs and herbaceous plants and bryophytes that occur in association with exotic grasses on the Ashton Flats and on the hummocky glacial terrain between the Mavora Lakes Road and the edge of the Snowdon Forest.
6.1.2 Copper Tussockland
A section of the Oreti trail passes through an extensive area of copper tussockland associated with an extensive low river terrace and floodplain upstream of the start of the consent section of trail.
Construction of the trail will result in the removal of mature tussocks along the trail alignment. The proportion of copper tussocks removed for the trail will be of a minor scale as the overall cover of copper tussock is extensive across the terrace and floodplain.
6.1.3 Shrubland
Shrubland affected by the proposed trail is generally associated with the steep hillslopes and rocky knolls and beech forest remnants overlooking the Oreti River in the vicinity of and downstream of Three Kings. The shrubland is of a variable density with intervening areas covered in pasture grasses and bracken.
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Extensive areas of matagouri dominated shrubland cover some of the lower river terraces next to the Mararoa River downstream of the Snowdon Forest Conservation Area.
The extent of clearance will be dependent on the density of the shrubland (and scrub) cover and the nature of the terrain traversed by the trail. The terrain will influence the number of and radius of the switchbacks required to maintain the 3 degree gradient specification and thus the extent of shrubland cover requiring removal. The width of the corridor created through the shrubland will vary from 3 to 6 metres depending on the extent of battering required especially on steeper terrain.
Clearance of shrubland vegetation along the trail corridor should be undertaken using a scrub cutter to minimise damage to vegetation beyond the defined corridor, especially areas where the shrubland cover is dense.
Generally along both routes the shrubland is either localised or sparse enough that most of the shrubland cover can be avoided or allow a trail to be constructed through them without requiring removal of individual shrubs. Minor trimming of shrubs is advocated as opposed to complete removal in order to minimise loss of cover.
Where a corridor is required through thicker shrubland care should be taken when defining the actual alignment to avoid any large specimens of shrubs wherever possible in view of their scarcity at a local level.
A sensitive approach to the trail works in the vicinity of the rocky knolls including the outcrop near Three Kings is also required to minimise the extent of ground disturbance in areas where a diversity of shrubland cover and high quality habitat for lizards and invertebrates exists.
In other sensitive areas such as the boulderfield on the South Ashton Flat the trail route (which follows the unformed legal road) deviates from the 4WD track and passes through shrubland amongst large boulders fringing the Oreti River. Some minor trimming of mingimingi shrubs is advocated as opposed to complete removal of individual shrubs in order to minimise loss of cover.
The edge effects arising from the creation of the trail corridor through the shrubland is considered to be minor due to variable density of the shrubland cover and tolerance of this vegetation to climatic extremes.
Woody vegetation cleared to create the trail corridor through shrubland cover should be chipped or stockpiled and either disposed of off-site or temporarily stockpiled for restoration purposes aimed at enhancing re-vegetation of areas of exposed soils such as cut batters. Other proposed avoidance and mitigation measures set out in Section 7.
6.2.4 Oreti Riverbed
A bridge crossing the Oreti River upstream of the Trig 14191 knoll will span a braided section of the river. The bed of the Oreti River like many braided rivers in the south and east of the South Island is utilised by various species of aquatic birds for breeding. These include the nationally threatened black-fronted tern and black-billed gull. To avoid disturbance to birds that may breed in the immediate reach it is recommended that construction of the bridge takes place outside the breeding season, pending advice from the Department of Conservation (DOC). In the event that no breeding pairs are observed by DOC staff then construction could occur during the breeding season.
6.2.5 Beech Forest
Short sections of the Oreti and Mararoa Valley routes pass through areas of beech forest necessitating sensitive construction techniques. In these areas removal or damage to canopy trees needs to be avoided. Where tree removal is required this will be limited to individual saplings or young trees in the understorey. Pole stands should be avoided to reduce potential wind tunnel effects.
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A narrower trail formation of 2.8 metres will be formed within the forested sections to minimise damage to vegetation beyond the trail formation. The narrower formation will allow the trail to be “weaved” around canopy trees, Careful selection of the alignment at this location is essential to keep the extent of clearance of understorey vegetation including regenerating beech trees to a minimum.
One section of the Oreti Valley route passes through an area of beech forest south of Three Kings where the steep terrain requires construction of several long sweeping switchbacks. Where cut batters are required these should be formed at a steep angle to keep the corridor as narrow as possible and should be carefully constructed to ensure they do not cause damage to any root plates of beech trees situated immediately upslope of the trail.
Minimising damage to forest vegetation beyond the trail cannot be over emphasised as this will assist in reducing wind tunnelling effects and consequent damage from wind throw. Careful removal of trees will be required to minimise damage beyond the actual trail formation. It is recommended that a logging contractor is engaged to ensure this work is undertaken as proficiently as possible. This is outlined in the following section dealing with mitigation measures. Other mitigation measures proposed include avoidance of stockpiling of logs and ensuring the logs are cut into small pieces to speed up the decomposition process and reduce the potential outbreak of pin hole borer.
6.2.6 Seepages and Streams
The Oreti Valley route and to a lesser extent the Mararoa route cross a number of streams, ephemeral floodplain channels and permanently and seasonally boggy areas. The streams will be spanned by short bridges or culverts depending on their size and gradient. In other situations such as the streams draining the large wetland complexes on the north Ashton Flat, these will be bridged to ensure there is no possibility of any alteration to the hydrology of the wetlands.
Where the trails are routed across parts of floodplains they will be constructed across the more elevated drier areas while any obvious flood channels will either be bridged or culverted. However a causeway will be constructed across the floodplain immediately beyond the Oreti River bridge due to the number of floodway channels and to maintain a consistent gradient between the bridge and the terrace beyond the floodplain.
Boggy areas associated with seepage zones and areas of impeded drainage where sedgeland, rushland and turf wetland communities usually prevail will either be spanned by short bridges or board walked depending on the extent of the boggy areas encountered along the routes. Where board walking is deemed the most appropriate means of traversing boggy areas, extra care needs to be taken to avoid, wherever possible, machinery movements in these areas so as to avoid long term damage caused by impaction. Ideally the boardwalks including the supporting piers should be constructed by hand with machinery used solely in the carriage of building materials to suitable storage sites on “dry” land at either end of the board walked sections.
Where significant seepages occur such as along the base of steep hillslopes south of the Upper Oreti Hut, trail construction will involve formation of water tables and installation of a number of short culverts to convey water under the trail. Surplus peaty material derived from the earthworks will need to be transported to a nearby dump site for disposal. The extent of earthworks involved will generally be of a minor scale and exposed areas of earth, including low batters are expected to be re-colonised by sedges and other wetland plants in a short period of time.
6.2 Gravel Borrow Areas, Dump Sites and Machinery Storage Sites
Gravel borrow areas, dump sites and machinery storage sites will be located on modified sites such as those dominated by exotic pasture grasses and will be situated at a minimum distance (>50 metres) from any watercourse or wetland to minimise the potential for off-site sedimentation effects. These sites will be reinstated, including re-seeding with exotic pasture grasses at the conclusion of the works.
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6.3 Operation of Cycle Trail
6.3.1 Vegetation Management
Ongoing vegetation management will be required to maintain a safe carriageway width for cyclists. This will include periodic trimming or pruning of branches, regenerating beech saplings and shrubs growing along the margins of the trail.
Invasion of exposed areas of soil by problem weed species is a possibility and requires a programmed approach to the control of these plants should they establish. The location and extent of control of weed species will be governed by regular monitoring of the trail, as outlined in Section 7 of this report. Regular maintenance using chemical and non chemical control methods as appropriate will prevent more widespread establishment of problem weed species.
6.3.2 Human Intrusion
The effect of the project on the local ecology and in particular wildlife is hard to predict. While the degree of disturbance arising from cycling is considered minor, there may be some degree of displacement of adjacent areas by sensitive fauna, especially aquatic birds that nest on the bed of the Oreti River. While the majority of this section of the trail is located away from the riverbed, the passage of cyclists across the bridge and causeway may result in the breeding pairs of some species avoiding the immediate reach.
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7 Proposed Avoidance and Mitigation Measures
7.1 Route Alignment
In terms of route alignment the priorities from an ecological perspective is to avoid sites of ecological value including wetlands, boulderfields, screes and areas of shrubland or scrub associated with boulderfields and screes.
Where practicable the route alignment chosen should minimise the degree of clearance of forest, scrub and shrubland vegetation to a practical minimum and minimising the degree of disruption to ecotones at the scrub/forest, scrub/wetland and scrub/grassland interfaces. These are areas of high habitat value.
Within the forested areas the alignment will be chosen so as to avoid canopy trees and potential bat roosting trees as discussed in Section 7.2.1 below.
While the trail routes selected generally avoids many of the wetlands associated with the flood plains, side streams and seepage zones, there are several small sections of the trail where wetland areas such as sedgelands cannot be feasibility avoided due to constraints imposed by the surrounding terrain. This applies to seepage zones south of the Upper Oreti Hut and some sections of trail that cross seepage areas by toe slopes abutting low river terraces and floodplains down valley of the Three Kings. Along these sections, short boardwalks are recommended so as to minimise disturbance to these sensitive areas.
With respect to the South Aston Flat boulderfield a route is proposed around the edge of the boulderfield by a tributary stream of the Oreti River. In recognition of the ecological value of the boulderfield, there will be no displacement of the boulders and boardwalks will be established near the stream channel to span depressions and gaps between the boulders. Shrubland vegetation growing between boulders will be trimmed rather than removed during construction of the trail.
An embankment that will be constructed across the floodplain from the Oreti River Bridge to a low terrace beyond the floodplain will be aligned to avoid an area of shrubland associated with screes that cover the lower slopes of an adjacent hillslope in recognition of the ecological value of the scree/shrubland complex.
The actual trail alignment shall be clearly defined on the ground by a supervising engineer in collaboration with an ecologist in advance of construction.
7.2 Mitigating Effects of Construction
7.2.1 Site Definition
The construction zones required for the trail and access/haul roads, gravel borrow areas, dump sites, storage sites for construction materials and machinery and toilets shall be clearly defined on the ground by a supervising engineer in collaboration with an ecologist in advance of construction. Definition of these sites on the ground is a bottom line requirement when working in any environmentally sensitive areas and would likely form a condition attached to any concession granted by DOC1 and in the contract documentation.
Potential bat roosting trees shall be identified by a representative from DOC along the trail routes that pass through areas of mountain beech forest. The marking of these trees shall be undertaken at the same time that the route alignment/corridor is defined on the ground to ensure these trees are avoided.
1 With respect to the Snowdon Forest Conservation Area
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Markers delineating the trail corridor extent and working areas should remain in place until construction of the project has been completed and certificate of compliance issued to the contractor.
7.2.2 Earthworks
Spoil generated during the earthworks/trail formation works should be either used in the creation of fill embankments or used in the trail formation. Side-casting of spoil should be avoided as this would result in damage to vegetation and potentially sensitive habitats that exist beyond the construction zone.
All earthworks should be undertaken using an appropriately sized excavator or bobcat as opposed to a bulldozer to ensure these works are undertaken as sensitively as possible. Selection of machinery will be guided by the need to create as narrow a corridor as possible, particularly on the hill slope sections where cut and fill earthworks are required. Care in the movement of machinery is also required to avoid destruction of the ground cover beyond the defined trail corridor
Appropriate machinery selection and operation ensures the extent of earthworks is minimised where possible thereby reducing the potential for the margins of the trail being colonised by invasive exotic weeds.
7.2.3 Vegetation Clearance
Any beech trees with a diameter at breast height (dbh) >150mm should be felled by a specialist logging contractor. Prior to felling these trees should be clearly marked by a supervising engineer in the company of a representative from DOC.
A logging contractor has the expertise to employ varying felling techniques depending on the nature of the terrain and density of stems. In most situations this will include directional felling to avoid or minimise damage to vegetation beyond the trail corridor.
Small trees (with a dbh <150mm) and shrubs should be able to be felled along the alignment of the trail using an excavator or similar machine once the larger trees have been felled and removed from the site.
Clearance of shrubland vegetation along the trail route should be undertaken using a scrub cutter as opposed to clearing the vegetation using a bobcat or small excavator. Felling the shrubs along the trail corridor using a scrub cutter will allow lizards and in particular geckos which favour shrubland habitat the opportunity to escape into the surrounding cover.
7.2.4 Vegetation Disposal
Any trees other than saplings felled along the forested sections of the trail should be cut into short (1 to 2 metres) sections to reduce the risk of outbreak and attack by pinhole borers which could affect the adjacent forest. Scheduling of tree felling and clearance to autumn and early winter further reduces the risk of attack. Cutting the logs into small sections also speeds up the decomposition process. A proportion of the felled trees should also be chipped to provide mulch that can be used for restoration purposes, particularly in the restoration of cut batters and other areas of exposed soil. No felled vegetation should be deposited outside of the defined trail corridor.
Shrubs cleared from sections of trail constructed through areas of scrub and shrubland should be back- loaded onto trucks and transported to designated sites for chipping. A proportion of this material could similarly be used as mulch for restoration purposes.
Tussocks and turf removed during the initial stages of trail formation across the grasslands should be back-loaded onto trucks and transported to designated dump sites such as excavations in natural depressions in grassland areas beyond the cycle trail. The layers of turf should be carefully placed across these sites so as to allow for early re-establishment of the ground cover. At no time should plant material be temporarily or permanently placed alongside the trail margins as this will lead to crushing and die off of surrounding grassland vegetation including tussocks.
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7.2.5 Timing of Riverbed Works
To avoid disturbance to breeding pairs of threatened bird species, it is recommended that construction of the bridge across the Oreti River takes place outside the breeding season (between September and December inclusive), pending advice from DOC. Advice received from the Department will confirm presence or otherwise of breeding pairs along the affected reach. Construction of the bridge could take place during the breeding season if no breeding pairs are observed.
7.2.6 Restoration of Areas Affected by Earthworks
At the outset of the earthworks within the beech forest remnants covering steep sloping land south of Three Kings and on a prominent terrace riser within the Snowdon Forest Conservation Area, organic humus and duff layers shall be scraped off along the defined trail corridor and stored at a designated site. Once the works are completed, this material should be deposited across the exposed batters and fill embankments along the corridor. Where appropriate mulch should be placed over the top of the material to hold it in place or alternatively, appropriate matting material such as bio-mat should be used on the steeper higher batters to help stabilise and hold the organic material in place.
Within the steeper areas covered in scrub and shrubland, mulch derived from chipping of shrubs removed from the corridor should be placed on the cut and fill batters and held in pace with appropriate matting material.
Placement of humus and duff material as well as the mulch will assist in the establishment of the beech and shrub vegetation along these exposed areas at the margins of the trail, thereby providing in a relatively short period of time, a “naturalised“ corridor that is consistent with its setting.
7.2.7 Noxious Weed Control
All machinery used in construction must be water blasted prior to entry to site to avoid the introduction of new problem weed species.
It is noted that nearby weed seed sources exist in the area including tree lupin which occurs in patches on the floodplains upstream of Three Kings while a more extensive cover of tree lupin, gorse and broom exists adjacent to the Oreti River further downstream.
Over a period of five years following construction of the cycle trail, the SDC should be responsible for the eradication of any new problem weed species which may establish on site. The control measures should be initiated following programmed rounds of monthly monitoring along the trail as referred to in section 8. These control measures would include a combination of spraying and hand-pulling depending on the species involved and extent of infestation.
7.2.8 Protection of Lizards
Immediately prior to removing tussocks and the turf of exotic grasses along sections of trail crossing areas of grassland, the contractor shall walk along the trail alignment for a distance of up to 50 metres to “flush” any lizards that may be present in the grassland.
Clearance of shrubland vegetation along the trail route as noted in Section 7.2.3 should be undertaken using a scrub cutter as opposed to clearing the vegetation using a bobcat or small excavator. Felling the shrubs along the trail corridor using a scrub cutter will allow lizards and in particular geckos which favour shrubland habitat the opportunity to escape. Clearing shrubland vegetation in this fashion reduces the potential for lizard injury or mortality.2
2 All native lizards are protected by the Wildlife Act 1953, and their habitats by the Resource Management Act 1991.
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8 Monitoring
Over a five year period following construction of the cycle trail, the following monitoring programmes are recommended:
Monthly inspections along the trail for the first two years following construction followed by quarterly inspections in years 3 to 5 to detect and control any new problem weed species that might have established, paying particular attention to previously disturbed sites such as the cut and fill batters and the construction zones; Yearly inspections of the rehabilitated areas, notably cut and fill batters in the forested sections and in areas of shrubland vegetation to assess degree of regeneration of seedlings as well as degree of recovery of fringing vegetation that has been disturbed during trail construction; Establishment of fixed photo points at a number of locations along the trail at the conclusion of construction in order to monitor broad changes in vegetation cover and community composition. The photo point sites would be determined in consultation with DOC.
The rate of recovery of sites disturbed during construction will have a significant bearing on the susceptibility or otherwise of these sites to invasion by adventive species and possibly problem weed species.
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9 Conclusions
The proposed cycle trail options span a range of landforms and vegetation/habitat types. Much of the indigenous vegetation along the routes has been modified by grazing and fires and invasion by introduced mammals and adventive plants.
Significant indigenous vegetation and significant habitats of indigenous fauna encompass the beech forest within Snowdon Forest Conservation Area, the wetland complex situated on the North Ashton Flat, the boulderfield on the South Ashton Flat and shrublands and scrub associated with screes and other rocky terrain.
No nationally threatened plants were observed during the field inspections along the Oreti Valley option and initial section of Mararoa route within the Snowdon Forest Conservation Area.
The nationally threatened New Zealand Falcon, black fronted turn and black-billed gull reside permanently or seasonally in the affected reaches of the Oreti and Mararoa valleys.
Measures to avoid or mitigate adverse effects on the indigenous vegetation cover and wildlife habitats are proposed. These include the avoidance of sensitive areas such as the scree/shrubland complex near the Oreti Bridge crossing and selection of alignments that minimise impacts on ecotones and use of bridges boardwalks to reduce disturbance to valley floor wetlands, including alterations to hydrology.
The construction of either the Oreti or the Mararoa valley trails will result in less removal of beech forest and grey shrubland vegetation compared to the original proposal (Route Option 5A) which traverses river terraces and spurs beyond the true left bank of the Oreti River between Trig 14191 and Windy Hill within the Eyre Mountains Conservation Park.
The cycle trail provides an opportunity for New Zealanders and overseas visitors to experience a remote part of the country and appreciate the natural history of the Oreti and Mararoa Valleys.
Status: Final September 2014 Project number: 80506020 Page 23 Our ref: Terrestrial Ecology Report
Southland District Council Round the Mountain Cycle Trail Terrestrial Ecology Report
References
Department of Conservation. 2000. Mainland Southland-West Otago Conservation Management Strategy 1995. Southland Conservation Management Planning Series No.5. Invercargill.
Hitchmough, R., Bull, L. and Cromarty, P. 2007. New Zealand Threat Classification System Lists. Science & Technical Publishing, Department of Conservation, Wellington.
Institute of Geological & Nuclear Sciences, 2000. Geology of the Wakatipu Area: 1:250,000 Geological Map 18. Lower Hutt, New Zealand.
Johnson, P. & Brooke, P. 1998. Wetland Plants in New Zealand. Manaaki Whenua Press.
McEwen, W. M., 1987. Ecological Regions and Districts of New Zealand. NZ Topographic Map (1:500,000). Third Revised Edition - Sheet 4. Department of Conservation, Wellington, New Zealand.
Ministry for the Environment, 2003. Land Environments of New Zealand, David Bateman Ltd, Auckland.
Ministry for the Environment, 2007. Environment New Zealand 2007.
Poole, A.L. & Adams, N.M., 1990. Trees and Shrubs of New Zealand. NZ Government Printer, Wellington.
Rance, B. 1998. Ashton Flats - Botanical Report. Unpublished report.
Robertson, C.J.R; Hyvonen, P; Fraser, M.J; Pickard, C.R. 2007. Atlas of Bird Distribution in New Zealand. 1999-2004. The Ornithological Society of New Zealand, Inc., Wellington.
Wilson, H., & Galloway, T., 1993. Small-leaved shrubs of New Zealand. Manuka Press, Christchurch, NZ.
Status: Final September 2014 Project number: 80506020 Page 24 Our ref: Terrestrial Ecology Report
Southland District Council Round the Mountain Cycle Trail Terrestrial Ecology Report
Appendix 1: Plant Species List
The following is a list of native and naturalised plants observed across the site during the course of the site visit. This list is by no means exhaustive and identifies the more common plants encountered on the site. Nomenclature for indigenous plants follows Poole and Adams (1990), Wilson (1993), Johnson & Brooke (1998) and for naturalised plants (indicated by *) follows treatments in Healy & Edgar (1980).
Trees and Shrubs Mountain beech Nothofagus solandri var. cliffortioides Silver beech Nothofagus menziesii Hall’s totara Podocarpus cunninghamii Bog pine Halocarpus bidwillii Manuka Leptospermum scoparium Mountain toatoa Phyllocladus alpinus Mountain ribbonwood Hoheria lyalli Kohuhu Pittosporum tenufolium Whipcord hebe Hebe propinqua Koromiko Hebe salicifolia Hebe pauciramosa Hebe odora Rohutu Neomyrtus pedunculata Prickly mingimingi Cyathodes juniperina Matagouri Discaria toumatou Mingimingi Coprosma propinqua Coprosma rigida Coprosma cheesemanii Coprosma rugosa Coprosma colensoi Coprosma tayloriae Coprosma virescens Coprosma ciliata Coprosma intertexta Coprosma petrei Olearia aviennicifolia Olearia bullata Olearia virgata var. virgata Porcupine shrub Melicytus alpinus Native broom Carmichaelia virgata Corokia Corokia cotoneaster Shrubby wineberry Aristotelia fruitosa Mountain heath Leucopogon colensoi Cottonwood Ozothamnus vauvilliersii Inaka Dracophyllum longifolium Dracophyllum uniflorum Helichyrsum selago Gaultheria antipoda Tutu Coraria sarmentosa Gorse* Ulex europaeus Broom Cytisus scoparius Sweet briar* Rosa rubinginosa Tree lupin* Lupinus arboreus
Sub-Shrubs Native daphne Pimelea oreophila Gaultheria depressa var. novae-zealandiae Pernettya macrostigma
Status: Final September 2014 Project number: 80506020 Our ref: Terrestrial Ecology Report
Southland District Council Round the Mountain Cycle Trail Terrestrial Ecology Report
Leucopogon fraseri
Lianes and scramblers Bush lawyer Rubus schmidelioides Bush lawyer Rubus cissoides
Ferns Bracken Pteridium escalatum Blechnum minus Blechnum penna-marina Prickly shield fern Polystichum vestitum
Grasses, Sedges and Rushes Toetoe Cortaderia toetoe Rush* Juncus effusus Native rush Juncus gregiflorus Juncus novae-zelandiae Juncus articulatus* Carex virgata Carex coriacaea Carex sinclarii Carex ovalis Eleocharis actua Hook grass Uncinia spp. Maori onion Bulbinella angustifolia Comb sedge Oreobolus pectinatus Snow tussock Chionochloa rigida Short tussock Festuca novae-zelandiae Blue tussock Poa colensoi Silver tussock Poa cita Chewings fescue* Festuca rubra Yorkshire fog* Holcus lanatus Creeping bent* Agrostis capillaris Sweet vernal* Anthoxanthum odoratum Cocksfoot* Dactylis glomerata Crested Dog’s Tail* Cynosurus cristatus Timothy* Phleum pratense Kentucky bluegrass* Poa pratensis
Dicotyledonous Plants Aciphylla glaucescens Golden spaniard Aciphylla aurea Hydrocotyle salcata Bidibid Aceana anserinifolia Ranunculus lappaceous Gnaphalium audax Celmisia gracilenta Raoulia subsericea Raoulia australis Senecio bellidoides Creeping pohuehue Muhlenbeckia axillaris Mouse eared hawkweed* Hieracium pilosella Himalayan honeysuckle* Leycesteria formosa Blackberry* Rubus fruticosus Moth mullein* Verbascum virgatum Scots thistle* Cirsium vulgare
Status: Final September 2014 Project number: 80506020 Our ref: Terrestrial Ecology Report
Southland District Council Round the Mountain Cycle Trail Terrestrial Ecology Report
California thistle* Cirsium arvense Groundsel* Senecio sp. Broadleaved plantain* Plantago major Sorrell* Rumex acetosella Yarrow* Achillea millefolium Selfheal* Prunella vulgaris Catsear* Hypochaeris radicata Lotus* Lotus pedunculatus
Club Mosses Clubmoss Lycopodium fastigiatum
Mosses and Liverworts Rhacomitrium languinosum Hypnum cupressiforme Drepanocladus sp Dicranoloma sp. Sphagnum cristatum Marchantia sp. Schistochila sp. Sphaerophorus tener Old Man’s Beard Usnea sp.
Status: Final September 2014 Project number: 80506020 Our ref: Terrestrial Ecology Report
Southland District Council Round the Mountain Cycle Trail Terrestrial Ecology Report
Appendix 2: Site Photographs
Status: Final September 2014 Project number: 80506020 Our ref: Terrestrial Ecology Report
Section 1MV
1: Initial section of trail route crossing modified short tussockland next to mountain beech forest. Mavora Lakes Road is visible in the background.
x
2: View south along trail route following an existing 4WD track. Red Stag Lodge is in the background. The trail route would enter the mountain beech forest around point x.
3: The mountain beech forest interior showing varying age classes of mountain and silver beech trees encountered along the route. The forest floor is covered extensively with mosses (Dicranoloma spp.).
x
4: The approximate exit point from the forest on to Haycocks Station as indicated. Much of the forest route would be on the higher terrace. Section 2MV
5: A downstream view showing flight of terraces that the trail route would descend to the margins of the Mararoa River.
6: Aerial view of showing section of trail route which would follow the fenceline near the river bank. The route would skirt a large floodplain of copper tussock/unimproved pasture and numerous flood channels. Boardwalks would be constructed across the channels near their confluences with the Mararoa River.
7: Aerial view showing an area of matagouri-mingimingi scrub bordering the boundary fence of the Haycocks Station and the trail route.
8: Aerial view of matagouri-mingimingi scrub covering terrace riser. The trial route would follow the 4WD track and fenceline that bisects shrubland on the river terrace.
9: Aerial view of a broad terrace of mixed shrubland/ semi-improved pasture which the trail route would skirt.
x
10: Aerial view of the braided Mararoa River and point of exit to the Mavora Lakes Road as indicated. Section 1OV
1: Modified short tussockland that typifies much of the drier parts of the Ashton Flats - North showing scattered tussocks of Festuca novae-zelandiae, extensive grey green mats of the moss Racomitrium languinosum and the exotic grasses browntop and Chewings fescue.
2: Large wetland near southern end of the Ashton Flats - North showing Carex sedgeland in foreground (Carex virgata) with open water with emergent Eleocharis actua at left of picture and rushland in the distance, dominated by Juncus effusus.
3: Aston Burn crossing point showing tussocks of Chionocloa rigida lining both banks of the river along with the occasional flowering heads of the spaniard Aciphylla glaucescens. Lincoln Hill is evident in the distance at centre right of photograph.
4: A shrub of the much branched broom Carmichaelia virgata encountered near the Ashton Burn. This specimen is about 2 metres high. Section 2OV
5: Mature stands of matagouri on alluvial fan near the Upper Oreti hut
6: Extensive wetland communities of copper tussockland, Carex sedgeland and Juncus rushland on the valley floor interspersed amongst exotic grassland communities south of the Upper Oreti hut.
x
7: Aerial view of boulderfield that bisects Ashton Flat South showing tributary stream of the Oreti River in foreground and indicative trail route. The location of the large boulder shown on photograph 10 is indicated.
8: View of shrubland at northern end of boulderfield.
9: Small trees and shrubs prevalent in boulderfield include matagouri, mingimingi, stunted mountain beech, Olearia bullata, Hebe odora and Coprosma tayloriae
X
10: Part of a tributary watercourse that flows between boulders that would be boardwalked.
Boulderfield
11: View from Trig 14191 across Ashton Flats South showing series of river terraces dominated by exotic grassland/short tussockland and discrete stands of matagouri.
12: Aerial view of Oreti River showing floodplain and indicative location of bridge crossing (dashed) and causeway (dotted). Ashton Flat South is at right of picture. Section 3OV
z \ x
13: Aerial view of Oreti River taken above bridge crossing looking downstream towards Trig 14191 (marked x) and isolated area of mountain beech forest bordering Centre Hill Station in the distance (marked z).
14: Shrubland community and screes covering toe slopes abutting floodplain. Bridge crossing point is towards top of photograph indicated as a yellow dashed line. The yellow dotted line indicates approximate alignment of causeway beyond bridge abutment
15: Route down valley would initially follow following Centre Hill Station boundary fence across unimproved pasture.
16: The route would follow the edge of this remnant of mountain beech forest entering the forest for a short distance at right of photograph.
17: Patch of matagouri on low terrace riser separating Centre Hill Station from large area of rushland associated with floodplain. The trail route would traverse along the edge of the terrace adjacent to the fenceline.
18: Matagouri-mingimingi shrubland the route would traverse through as it climbs towards a rocky outcrop near Three Kings. Section 4OV
19: Upstream view of Oreti River from outcrop showing patches of grey shrubland of varying density. Part of the Three Kings rock formations evident at right of photograph. Indicative trail route indicated.
20: Large area of matagouri dominant grey shrubland to the south of promontory with indicative trail route down valley shown.
21: Steep slopes within interior of small remnant of mountain beech forest where trail switch backs would be required.
22: Copper tussock and tall exotic grassland associated with lower terrace beyond mountain beech forest remnant. Photograph taken along trail route alignment.
23: View up valley showing indicative trail route through mountain beech remnant, unimproved pasture and area of grey shrubland.
24: View along trail from a crossing point with causeway across this shallow gully containing copper tussocks, sedges and exotic grasses. The trail switch backs through mixed matagouri shrubland and unimproved pasture in the distance.
25: Extensive area of mixed shrubland adjacent to the trail route. Plants evident within the shrubland are matagouri, mingimingi, mountain cottonwood, golden spaniard and bracken
26: Looking upslope along alignment of trail route where this passes through part of the shrubland in order to maintain a three degree gradient.
x
27: View downstream showing route of trial across a dry section of an extensive terrace of unimproved pasture towards point x where a cutting would be excavated near the Centre Hill Station homestead.
28: Photograph taken from point X looking in opposite direction. The trail route would follow the 4WD track at a 5% gradient through cutting to be made at this location. The trial route would avoid a small wetland at right of photograph and area of shrubland covering the knoll beyond the track.
29: Looking in an up valley direction along alignment of trail route on elevated ground bordering copper tussockland wetland.
o
30: Extensive copper tussockland cover associated with an extensive floodplain that trail route would pass through. The consented section of the trail commences by the right side of the distant rock outcrop (marked o) in centre left of photograph.