BEFORE THE ENVIRONMENT COURT REGISTRY

IN THE MATTER OF The Resource Management Act 1991

AND

IN THE MATTER OF an appeal pursuant to section 120 of the Act

BETWEEN MANGAWHAI HARBOUR RESTORATION SOCIETY INCORPORATED (ENV-2011-AKL-000110)

Appellant

AND NORTHLAND REGIONAL COUNCIL

Respondent

AND DIRECTOR-GENERAL OF CONSERVATION, ROYAL FOREST AND PROTECTION SOCIETY INCORPORATED AND 12 OTHERS

Section 274 parties

STATEMENT OF EVIDENCE OF ANTONY JULIAN BEAUCHAMP

2 March 2012

Glen Houghton 149-151 Bank Street, PO Box 842 Solicitor WHANGAREI for Director General of Conservation Phone: 09 470 3340 Email: [email protected] Fax: 09 470 3301

A. Introduction

1. My name is Antony Julian Beauchamp. I hold the qualification of Ph.D in Zoology and a post graduate diploma in Environmental Health. I have been a member of the Ornithological Society of for 32 years.

2. I have worked for the Department of Conservation in Northland since 2001 firstly as Conservancy Advisory Scientist until 2008 and then as the Technical Support Officer Ecology and Environment. Between 1991 and 2000 I worked for Northland Health Limited as a Health Protection Officer administering the USDA shellfish sanitation quality assurance programme. This included sampling shellfish from throughout Northland for marine biotoxins. Between 1979 and 1986 I was a laboratory assistant in the zoology and ecology laboratories at Victoria University.

3. I have a wide range of experience in undertaking and contracting biological research in Northland. I have been a member of the department’s, , brown teal, , native frog recovery groups. I have studied weka, the nearest living relative to the banded rail, since 1979 and published extensively on this species. I have also surveyed banded rails in part of Whangarei Harbour. I have sampled shellfish in most of Northland’s the estuaries and harbours and carried out invertebrate work on the dune systems in Bream Bay and Mangawhai. I have provided logistic and data support for the New Zealand fairy tern programme since 2006. I have provided evidence in the review of the mangroves section of the Northland Regional Coastal Plan and the designation of marine 1 area in Whangarei Harbour. I have surveyed many of the Northland harbour’s for also published material on the waders using Whangarei Harbour and Ruakaka Estuaries. I have recently studied aspects of human disturbance on the high tide roost at Ruakaka Estuary.

4. I have read the Code of Conduct for Expert Witnesses in the Environment Court practice Note (November 2011). This evidence has been prepared in accordance with it and I agree to comply with it. I have not omitted to consider material facts known to me that might alter or detract from the opinions expressed.

5. I have read the evidence of Dr Alfarao, Mr Bull, Dr Campbell, Mr Don, Mr La Bonte , Ms Curreen, Mr Coffey, Mr Townsend, Ms Lowe and Mr Riddell. I have seen the draft evidence of Dr Bellingham, Mr Southey, Mr Quinlan, Dr Ismar and Ms Wild.

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6. I have visited Mangawhai Harbour and sandspit for 20 years and have banded fairy tern chicks there since 2007. I dug cockles and pipi sometimes at a weekly basis from the channel in 1998-2000 for marine biotoxin analysis and counted birds on the sand flats at that time. I have advised the department on habitat issues on the sandspit. I have counted birds in the upper harbour during the past spring and summer and walked all of the sand flats above Moir Point recently and looked at all the habitats in all of the proposed zones for mangrove clearance.

7. My assessment is based on the revised application provided in Mr La Bonte and Mr Bull’s evidence. It seeks to remove all the mangrove downstream of the Molesworth Drive and Insley Street Causeways (c.32.5 ha), with an area between the Back Bay jetty and Kainui Street (9.25 ha) being currently left for assessment of nesting/foraging of threatened and/or endangered bird, before it will be included. The application also includes the dredging of a 25 m wide channel to depth of 1 m below the existing channel from north east of Moir Street to the Mangawhai Hotel. The dredged material of around 42,500 cubic metres is to be deposited onto currently tide covered areas of the southern shoreline, near the old wharf, and the mangrove island after mature mangroves have been removed. The applicants objectives are given in Mr Bull’s evidence (section 1.7) and I deal with aspects of the following objectives in my evidence. v. Enhance foraging and breeding habitat for fairy terns, shorebirds, wading birds and marine species vi. Restore open water/tidal flat views and expand the opportunities for viewing bird life and sea life vii Restore open water areas for appropriate recreational activities ix Create passive recreational areas as alternatives to use of the sandspit during summer bird nesting period

8. My general conclusion is that the removal of mangroves and undertaking the dredging applied for will be negative for shorebirds and waders and potentially catastrophic for fairy tern. It will open the harbour’s waders to increased disturbance and reduce the undisturbed areas available to them for foraging.

9. In my evidence I will cover the following aspects: • The New Zealand fairy tern management issues • Bird use of the mangrove habitat at Mangawhai • Open space maintenance for shorebirds and waders species • Disturbance

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The sand spit

10. The sand spit associated with Mangawhai Harbour is a nationally important breeding area for fairy tern ( Sternula nereis davisae, Nationally Critical) threatened waders including the Northern ( Charadrius obscurus aquilonius , Nationally Vulnerable), and the At Risk variable oystercatcher ( Haematopus unicolor , Recovering) (Sagar et al. 1999) and has an important colony of Caspian terns (Hydroprogne caspia , Nationally Vulnerable). Northern New Zealand dotterel also roost there in winter at up to 130 birds. Eastern bar-tailed godwit ( Limosa lapponica baueri ) and red knot ( Calidris canutus rogersi ) have been recorded as being present on the spit in summer since the mid 1990s in numbers of up to 600 and 350, respectively.

B. New Zealand Fairy tern management issues

Population trends

11. New Zealand fairy tern has been found to be genetically isolated from other species of fairy terns (Baling & Burton 2005). It differs from the Australian and New Caledonian fairy terns in being a solitary breeder, and requires open sand areas devoid of vegetation for nesting. It has historically been more widely distributed in New Zealand. In the 19th century fairy terns were recorded in inland braided rivers (Heather & Robertson 1996). By the mid 20th century fairy terns were mainly restricted to the area north of Auckland (Oliver 1955).

12. The number of breeding sites and pairs declined due to changes of land use, especially the conversion of open active sand systems to marram ( Ammophila arenaria ) in the 1930s, and then pine forest and farmland in the 1950-60s (McKelvey 1999, Moon 1988). The area lost included the dune system south of Mangawhai Sandspit. Recent breeding management suggests that predation by introduced mammals, is also likely to have also been important.

13. Estimates of the number of fairy terns and pairs present before colour banding commenced in 1991 is questionable due to potential confusion between fairy terns and little terns (Ferriera et al. 2005), which can only be distinguished by bill colour in the breeding season (Heather & Robertson 1996), and by the lack of robust surveys.

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14. The Pakiri – Te Arai beaches is reported to have had at least 8 pairs in the past (Moon 1988). One field guide indicates the total population was 18 pairs in the 1950s, but does not cite sources (Heather & Roberson 1996). A more recent assessment of the written records found that in the 1940-50s the minimum number alive was 11 birds and only 2 pairs (Ferreira et al. 2005). In 1987 the population used only 3 breeding sites - Mangawhai and Waipu on the east coast and Papakanui on the west coast (Wilson & Hansen 2005, Attachment 2; Fig 1). In 2004 a pair re-established at Pakiri near a site used up until 1965-66. Other small sites, including Poutaua, have been prospected by pairs but no birds have established at them yet. These sites are likely to only hold one breeding pair.

15. Dr Bellingham in his evidence has made reference to assessments of the remaining open active sand dune habitats potentially useful as breeding areas for fairy tern. These sites include areas where there were breeding fairy terns but changes in the environment have reduced their usefulness, or which are now outside the current known movements of the population. However, within the current non-breeding season distribution of the population are Skull Creek in Whangarei Harbour, and Manukapua Island in the Kaipara, Te Arai and Ruakaka Estuary. There is no recent breeding activity at any of these sites, and it is unlikely that any disruption to the existing breeding areas would result in movements to these areas.

16. At Ruakaka estuary, in 74 hours of survey between Oct 2009 and Mar 2010, only two passing flights of fairy terns were recorded (Beauchamp 2010). Ruakaka is not being used as a post breeding foraging and roost area. The disturbance there is so great that during peak summer even the most tolerant waders are restricted to fenced off high tide roost zones and the very least disturbed regions 1 (Beauchamp 2010). There are no recent records of fairy terns using the Ruakaka estuary at low tide.

Breeding at Mangawhai

17. Mangawhai Harbour has been used by New Zealand fairy terns since the 1940s when the Insley Street causeway area was used for foraging (Ross MacKenzie, field notes 1946-56 held in Auckland Museum) as it is now. Two pairs were recorded on the spit in December 1953 and in 1976 when Gwenda Pulham started working on fairy terns (Gwenda Pulham, pers com). During the past 17 years when mangroves have formed

1 The main disturbance factors are people walking, power boats, kayaks, kite boarders. Vehicles and dogs are banned from the area.

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part of Mangawhai Harbour’s environment, 2 to 5 pairs (36% - 60% of the breeding population) have used Mangawhai Sandspit and harbour for breeding.

18. Mangawhai Harbour is used by foraging fairy terns throughout the year. Pairs arrive there in September to re-establish pair bonds and undertake courtship feeding in preparation for nesting. First clutches peak in November and replacement clutches are laid until early January if nests are lost. There needs to be sufficient food to allow the female to recover from incubation and lay eggs. This is gained by the female doing her own foraging and receiving supplementary food from her partner. Only one or two chicks can be reared at the same time, and only one clutch 2 of chicks can be raised each year.

19. Fairy terns have been reported as having a high degree of infertility (Ferreira et al. 2005). However, this primarily relates to two males who were infertile and whose partners laid 61% of the 85 infertile eggs between 1995 and 2012. These pairings were used for surrogate parenting 9 times and fledged chicks. Their infertile eggs provided valuable dummy eggs for nest management. In the past season 82% (n=17) of the eggs were fertile and seven of the eight pairs that bred laid fertile eggs 3. In my view infertility is not an issue to the current population.

20. The records show that fairy terns return to the same site to breed over multiple years, and desert their breeding grounds reluctantly (Attachment 1, No 1).

21. The only mass desertion in the past few years occurred at Waipu, where for two consecutive breeding seasons (2009/10 and 2010/11) cats destroyed nests. This resulted in one pair and a single male moving to Mangawhai mid season in 2010/2011. In addition, a female that was paired at Waipu, laid two single-egg fertile clutches late in the season at Mangawhai. Her partner apparently did not leave Waipu, and no other male was seen incubating these eggs at Mangawhai. This pair nested successfully at Waipu in 2011/12 after the cats were removed (Zimmerman 2010, 2011).

22. The male of the pair that moved mid-season to Mangawhai in 2010/2011 disappeared, and his partner returned to Waipu in 2011/2012 and bred with a new

2 Group of eggs that hatch at the same time. 3 The only infertile pair includes one of the males mentioned as being infertile in previous sentences

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partner. The single male that moved to Mangawhai in 2010/2011 returned to Waipu in the 2011/2012 breeding season but lacked a partner.

23. Mangawhai is the largest and the most important current breeding site for fairy tern and the productivity loss from this site would make it very unlikely that New Zealand fairy tern could be saved from extinction. The New Zealand fairy tern already faces a 39 percent chance of extinction within 50 years due to a combination of other threats and uncontrollable factors like genetic drift, if the population size is not increased (Ferreira et al . 2005).

How foraging disruptions could impact fairy tern breeding

24. Fairy terns forage throughout the tidal cycle when they have young, but more food is delivered when the tide is between half outgoing and half incoming. They feed on the shallow margins of channels. Fairy terns teach their young to forage so true fledging takes place up to 68 days after they fly from the natal site at c. 30 days old (Preddey 2008). The last chicks leave natal areas in February and initially use their nearest harbour.

25. The majority of losses of fairy tern chicks cannot be directly related to food supplies. However, during storms the feeding rates of fairy tern chicks can be reduced to almost undetectable levels, and some chicks are lost. The reasons for these poor foraging rates have not been established, however, water clarity and wind disturbance of the water surface 4 are likely to be important, as are the ability of fairy terns to fly and find sheltered fishing areas. Fairy terns feed within areas with a mangrove fringe at both low and high tide when they need to get food for larger chicks, and the mangrove protected fringes may be more important during storms. During the past three breeding seasons we have not had high wind conditions and so have not collected data to further understand these relationships.

26. There is some evidence of how feeding disruption would cause problems to fairy tern breeding. In the 2009/2010 season a pair that used the oxbow lakes on the sand spit for foraging lost their food source due to temperature rises, de-oxygenation of the lakes and the loss of fish. In the period before the death of the fish this pair generally had one parent with the chicks at all times, and foraging return times from the lake

4 Fairy terns must be able to see their foods while hovering above them and turbidity and small waves may make this impossible in unsheltered areas in large bodies of water.

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were in the order of minutes. After the fish deaths both parents left to forage elsewhere and the return food delivery times increased to up to 2 hours. The lack of parental care exposed the chicks to pecking by a neighbouring breeding male (Zimmerman 2010). One parent returned with a dead fish, indicating that this bird may have been foraging many kilometres away.

27. Foraging area disruption was the principal reason why the related fairy tern ( Sternula n. nereis ) declined in the Coorong Estuary, South Australia, by more than 75% between 1984 and 2006. There, the fairy terns were forced to abandon their traditional safe breeding sites when adjustments to estuary salinity caused by water extraction in the Murray River, moved the fairy tern estuarine fish food resource to over 8 km from the breeding site. The distance was too far for fairy tern to sustain breeding as they can only transport one fish to chicks at a time. The population moved its breeding sites to those impacted by predators, but close enough (within 2 km) to their foraging areas (Paton & Rodgers 2009).

28. Mangrove removal will potentially expose muddy sediments to resuspension. In my experience the most likely time for re-suspension is by wind-generated waves during conditions of increasing and lowering tides. Any increase in the amount of duration of turbid water, or even turbidity on the margins of the channels could have substantial impacts on the ability of Fairy terns to find food. Any mangrove clearance would need to take account of the likely use of that area by fairy terns.

29. The above discussion indicates that fairy tern display considerable breeding site fidelity and that foraging environments need to be close to breeding sites. Disruption to foraging sites during the breeding season places chicks at risk.

30. We do not know if disruption to foraging sites or food resources in Mangawhai Harbour due to mangrove removal will cause any loss in fairy tern productivity, or dispersal of adults, but even the possibility of this is of considerable concern.

31. In my view, the risks of increased disturbance to the fairy tern foraging areas and food resources as a result of mangrove removal are more than minor.

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C. Bird use of mangrove and neighbouring habitats at Mangawhai

32. I undertook spring and summer low tide surveys of the resident birds within and near mangroves between Oct 2011 and Jan 2012, using fixed sites between the Insley Street and Molesworth Drive causeways (Attachment 2, Fig 2). Birds were counted within the region of transects. At sites T3, T4 and T6 the channel margins were sketched onto aerial photographs and the number of birds, their habitat and location of detection, and the presence of people were recorded (Attachment 1, No 2, 3 & 4). The location of banded rails were noted in one-off site assessments of 9 sites in Nov 2010 5 (Attachment 2, Fig 2). Starling and house sparrow flocks were counted 6 on their way to their night roost.

33. Counts and assessments are limited by small sample size, seasonality, lack of equality of effort, and an emphasis on the time the sand flats were exposed (Attachment 1, No 4 and 5). They do not cover the time that New Zealand migrant waders, South Island pied oystercatchers and ( Anarhynchus frontalis ) would be at their greatest numbers in Mangawhai Harbour. The statistics can only be considered indicate species presence and habitat location during spring and summer.

34. These surveys found 31 species of birds to be present in and around mangroves (Attachment 1, No 2) including three species using the mangrove zone 7 with threat rankings. These are banded rails, ( Gallirallus phillippensis assimilis ), white heron (Ardea modesta ) and bittern ( Botaurus poiciloptilus ).

35. In addition, the sand and channels near the mangroves were used by other threatened listed birds including; fairy terns, northern New Zealand dotterel (Charadrius obscurus aquilonius ), banded dotterel ( Charadrius bicinctus ), Caspian terns ( Hydroprogne caspia ), pied shag ( Phalacrocorax varius ), red-billed gull ( Larus scopulinus ), pied stilt (Himantopus himantopus leucocepalus ), South Island pied oystercatcher (Himantopus himantopus leucocepahalus ) and variable oystercatcher ( Haematopus unicolor ) (Miskelley et al. 2008).

5 By late evening and dawn point count survey of 9 sites in November 2010 when maximum calling is expected, and searching for footprints once in the surround of the southern shoreline (25/1/2012) and Lincoln Street (16/1/2011). 6 Counted twice on 18/11/2010 and 14/11/2011 7 Pneumatophores were treated separately in data collection but are considered to be part of the mangrove zone.

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Impacts on key threatened birds

Banded rails

36. Banded rails are very difficult to survey as they call infrequently outside of the pre- breeding season and do not respond well to tapes. Banded rails are using the mangroves in all land connected mangrove forest in the areas proposed to be removed at Mangawhai (Attachment 2, Fig 2, Graeme Don evidence 8). Banded rails are diurnal and crepuscular foragers (Elliott 1987). They were not recorded in the pneumatophore zone during lowering tides in day light in the upper harbour transect counts. However, a banded rail was seen at Lincoln Road 5 metres from the margin within the outer pneumatophore zone 9. Its location and entry point to oioi (Leptocarpus similis ) was observed but only three foot prints were found in a puddle of wet sand within the pneumatophore zone. The current record of banded rail presence and density is considered by me to be conservative.

37. The population size and distribution of banded rails in Northland is dependent on the presence of small areas of saltmarsh and their surrounding mangroves. Studies done at Ohiwa Harbour have found that banded rails would generally forage less than one and at most 6 m from area with only saltmarsh cover, but forage hundreds of metres into even scattered (0.5 m cover diameter) mangrove cover on low tide (Botha 2010).

38. The impact of total mangrove removal at all the proposed sites is very likely to reduce banded rails seaward of the causeways to only the Back Bay saltmarsh. Their presence on the southern margin will cease, due to the proposed sand deposition, and at Lincoln Road, due to the remaining saltmarsh being less that the 1.5 ha required by pairs (Elliott 1989). Removal of mangroves from the front of the Back Bay saltmarsh will also expose the saltmarsh to erosion, as is evident at the end of Pearson Street 10 . This would further reduce the habitat for banded rails and drive the remaining birds to seek refuge elsewhere. If other habitats are full, then birds will die or disperse from Mangawhai with the inherent risks of successfully finding and using new habitat.

8 Graeme Don’s surveys agree with my own except I found banded rails at Lincoln Street. 9 25/1/2012, 09:37 low tide. 10 Covered in Mr Townsend’s evidence

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39. In my opinion, the impact on the banded rail population of mangrove removal from half Mangawhai Harbour is likely to be negative and the impact on that population will be more than minor.

White Heron

40. White herons are in the highest threat category. Numbers appear to be stable at 100 birds but with declining recruitment (Miller 2001). White heron are seasonal users of estuaries in Northland, and generally only single individuals are recorded at the same sites at similar times each year (Beauchamp & Parrish 2007). A white heron was seen foraging in the channel within and beside pneumatophores above and below both the Insley Street and Molesworth Drive causeways between 16 October and 9 November 2012. Very little is known about the post breeding range of white heron and the impacts of disturbance of their non-breeding range.

Bittern

41. A bittern was seen in the pneumatophores just above the Insley Street causeway. Bittern require extensive areas for foraging 11 . There is a very good possibility that, like the white heron, this bird would use the neighbouring seaward margin mangroves for foraging.

Fairy tern

42. Fairy tern were seen during the surveys predominantly between Back Bay and the mangrove island (Attachment 2, Fig 2: T3) along the main channel (T4) and above and just below the Insley Street causeway bridge (T1). No foraging areas defence 12 was seen in the current surveys, but this has been seen in the past near the T3 count site.

Impacts on birds not listed as threatened

43. The impact of mangrove clearance on the more common species is generally considered to be no more than minor, because these species are not threatened nationally and can handle displacement or population decline, or do not use

11 Mark Bellingham’s evidence 12 At Waipu fairy terns appear to partition the foraging resources chasing intruders from sites. This behaviour has been seen at Mangawhai at this site in the past but was not observed during data collection.

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mangroves exclusively (Rayner 2011). This does not take into account the local impact on population and the potential impact on local ecological balance.

Mangrove Island roost

44. The mangrove island is used as a night roost by at least 3000 starlings ( Sturnus vulgaris ) and 1700 house sparrows (Passer domesticus ) in spring. Survey’s in Whangarei Harbour 13 indicate that in winter the number of birds using the roost could be 4 times higher (Attachment 1, No 5). Starlings tend to use one roost in a catchment and seek areas lacking rats. Roosts can be used for decades (Brockie 1983). The destruction of the mangrove island roost would force starlings to find alternative roost sites. These may have increased predation risks and create noise nuisance issues if they are near housing. Both starlings and house sparrows are considered to be pests in some circumstances. However, house sparrows destroy a lot of weed seeds, and starlings remove invertebrate pests from pasture (Szlivka 1987, Higgen et al. 2006).

D. Will changes enhance the habitat for open sand flat foraging birds?

45. It is the applicants intention is to increase the habitat for open sand flats foragers. These species include New Zealand dotterels, white-faced herons, pied stilts, oystercatchers, bar-tailed godwits and red knots.

46. In order to increase the number of waders, the correct foraging habitats need to be present, the waders have to be capable of dispersing to the harbour, and the habitats there must be preferred over those in other harbours.

47. The current birds using the area cleared of mangroves in 2004 do not include substantial numbers of threatened waders (Attachment 1, No 7) and the site is reverting to mangroves. The changes in the benthic community following mangrove removal shows that in the short-term these areas will have lower densities of shellfish than surrounding habitats (Alfaro 2010), so species like red knot will not use them (van de Kam 1999). The principal waders that will use these types of habitat for foraging are godwit, pied stilts, oystercatchers and white-faced heron.

13 In Whangarei harbour, the mangrove roost site used by starlings was only deserted when Limestone/Matakohe Island was made rat free.

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48. White-faced herons predominately use mangrove habitats (Attachment 1, No 2) and leave the mangroves to forage on open ground. The loss of mangroves from proposed sites will displace the white-fronted heron population seaward of the causeways, and reduce the numbers using the sand flats.

49. Mr Southey in his evidence provides the OSNZ counts of waders using the Mangawhai Sandspit high tide roost and harbour between 1994 and 2009. The average numbers were 366 godwits at an average of 1.24 birds per ha of sand flat (max 350 birds or 2.03 per ha 14 ) and 75 South Island pied oystercatchers at an average of 0.25 birds per ha of sand flat (max 600 birds or 0.72 per ha).

50. The national population prognosis for red knot and bar-tailed godwit is downward. Reclamation is reducing their foraging sites and roosts at their stopover sites to their breeding areas in the Yellow Sea (Battley et al. 2011). Colour banding studies of godwit and red knot in New Zealand show a very high level of foraging site attachment 15 by adult godwits, and greater movement by red knot (Bailey et al. 2012). Any long term increase in waders at Mangawhai Harbour will most likely occur from establishing juvenile godwits and South Island pied oystercatchers.

51. The amount of habitat that could be created by mangrove removal is small (c. 23.5 ha 16 ) in relation to the (c. 259 ha) of existing open sand flats. Any increase in the wader numbers would be modest. Based on current average numbers it would amount to 29 extra godwits in summer, and 6 extra South Island pied oystercatchers in winter. This is less that the annual variation in numbers of these species, so visible increases in wader population are not expected. It is also less than the likely losses of other partial open sand-flat foragers like white-faced herons 17 .

52. The current recommended permit conditions attached to Mr Bulls evidence states that “Re-establishing mangroves may be removed as required from areas”. Alfaro’s (2010) study indicates that areas will revert to mangroves if not managed. It may take a decade for the root mat of existing mangroves to degrade (Rayner 2011) and the benthos to change in favour of some species of wading birds. Mangrove removal without a commitment to ongoing follow-up may be of no benefit to shorebirds, and

14 Bases on GIS calculation of the areas of remaining sand flats at 295 ha. 15 Once established in a harbour or estuary they tend to return to that harbour each year. 16 Based on Mr Bulls evidence and assuming the southern shoreline and mangrove island areas as covered in sand as indicated in the proposed permit conditions 17 The minimum number of white-fronted herons in transects 3 and 6 were 46 birds (Attachment 1, No 5).

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just displace the bird species using mangroves, especially banded rail, white heron and white-faced herons.

E. What are the likely impacts of increased disturbance?

53. Mangrove removal will increase the openness and use of the upper harbour. The areas that I surveyed had limited disturbance, confined access points and most activities occurring there appeared passive. However, very limited data collected on transect T8 found no birds were recorded there during the highest period of human presence (10:40-12:50, 5/1/2012) and this may be indicative of what could happen with more disturbance in the upper harbour (Attachment 1, No 8).

54. Fifteen of the 46 groups of people seen during the recent surveys had dogs (n = 21), 12 (57%) were unleashed, and 3 were seen chasing birds.

55. The cumulative effect of human disturbance is difficult to model but work carried out at high tide at Ruakaka Estuary indicates that if human access is not controlled that waders, terns and shags will be restricted to the least disturbed sites, and in their absence they will leave the harbour (Beauchamp 2010).

56. Of greater concern is that the current walking traffic will increase over the entire mid and upper harbour, and that the removal of mangroves will provide greater access to vehicles and high speed water craft. In my surveys mass godwit movements occurred on the opposite side of the main channel when a motorbike moved at speed over the sand flats. Mass movements also occurred when only one person walked over the same open flats (Attachment 2, map 2; T4). The mangrove island provided visual barrier from the disturbance factors, and waders flew from the exposed sites to the area between Back Bay and the mangrove island (T3).

57. Currently, the sand flat encompassing the mangrove island is surrounded by channels and appears to be the region least disturbed by people. If the mangrove island is replaced with dredged sand it is likely to become a destination for recreational use and that will impact negatively on the surrounding bird foraging habitats there.

58. The proposed dredging will potentially allow greater access to the upper harbour by boats and kite-boarders in all tides. Kite boarding displaces foraging birds from

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channels and the surrounding flats, due to the speed and actions of the kite and the need for participants to recover and re-launch kites (Beauchamp 2009).

59. The impact of increased human activity and openness is likely to be reduced foraging opportunities for birds along the main channel, and an increase disturbance throughout. If current less favoured recreation sites, like those near mangroves are removed, then there will be no sites for waders to remain relatively undisturbed. This in my opinion would most likely reduce the numbers of wader numbers using Mangawhai Harbour.

F. Is there evidence of current mangrove expansion?

60. The upper tidal flats above Moirs Point were searched for juvenile mangroves, and there is little evidence of recent expansion (Attachment 2, Fig 3). The time that exposed sand was available between the pneumatophore zones of the mangrove island and Back Bay was between 5 and 6 hours. This is less than the 6 hours of dryness that mangrove propagates require to survive (Morrisey et al. 2010). The only propagules that were found on the outer tidal flats were newly established with cotyledons. These sites are exposed to wind-wave action which causes propagule death, and due to this it may take decades before there is any mangrove coverage of the existing flats (Morrisey et al. 2010).

61. There is no evidence that mangroves are rapidly taking over sandflats and impacting detrimentally on open sand bird communities. The habitats that Alfaro (2010) describes are being displaced by mangroves are still well represented in the harbour.

G. Policy assessment

62. Coffey et al. (2010) provides criteria for the assessment and ecological values of mangroves. I have to the extent of my experience undertaken an assessment against those criteria (Attachment 1, No. 9). The main conclusions from this assessment are: mangroves have been present at many sites for over 30 years; threatened species of birds will be put at risk by the total clearance of mangroves in most areas; the mangroves are not compromising bird roosts; and that mangroves are providing a buffer for bird foraging areas and connectivity between sites.

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63. The New Zealand Coastal Policy statement policy 11 on indigenous biodiversity protection includes two sections. Part a. requires people to avoid all effects of activities, and Part b. requires people to avoid significant effects of activities. In this case Criteria 11. a. (i) applies 18 . There are 13 species of birds in the upper reaches of Mangawhai Harbour that meet these criteria. Adverse effects are expected on some of these species as indicated in my presented evidence.

H. In conclusion:

64. The impact of mangrove removal is likely to be more than minor for banded rail and could be catastrophic for New Zealand fairy tern. Substantial disruption to fairy tern foraging could reduce productivity at fairy tern’s most important breeding site, making it difficult to grow the population and reduce the probability of extinction due to other factors.

65. Mangrove removal and dredging will increase the openness of the harbour below the causeways and the areas used by people, dogs and their vehicles. This is likely to be detrimental to the use of the area by all waders.

66. The habitat that will be created by mangrove removal will provide space for only a modest increase in the number of waders and then only if it is maintained free of mangroves in the long-term.

67. The major roost for the Mangawhai catchments starlings and house sparrows will be destroyed, and they will need to relocate to another area that may not be as acceptable to the inhabitants of Mangawhai.

68. There is no current evidence that the mangroves are expanding at a substantial rate. In my opinion holding the line is feasible in the long-term and the most precautionary approach.

18 “indigenous taxa that are listed as threatened or at risk in the New Zealand Threats Classification system listing”.

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