1 Vegetation Communities

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1 28 November 2005 Environment Waikato PO Box 4010 HAMILTON EAST Attention: Malene Felsing Re: Whangamata Mangrove Clearance & Saltmarsh Damage Dear Malene On 8 November 2005 I surveyed the area adjacent to the causeway across the Moana Anuanu Inlet, Whangamata, the site of recent mangrove clearance and burning operations. My findings were as follows. 1 Vegetation Communities 1.1 Mangroves The mangroves in the inlet mostly grow to 1-2m high, with occasional individual plants reaching 2.5m. They form a dense canopy over largely bare mud; the only other conspicuous vegetation within the mangal is the free-growing form of Neptune s necklace (Hormosira banksii), which lies among the mangrove pneumatophores. This is particularly dense along the margins of the main channel. A small, shaggy alga, Catenella fusiformis, grows on the mangrove trunks and pneumatophores. 1.2 Saltmarsh Immediately behind the mangroves there is a sharp transition to saltmarsh dominated by oioi (Leptocarpus similis) and marine rush (Juncus kraussii var. maritimus). The marine rush is slightly the more abundant of the two, with both growing together in some areas, while in other areas they grow as unmixed patches of several square metres in extent. Small mangrove seedlings (up to 20cm) are scattered among this, but there is little other vegetation until near the upper fringe of the saltmarsh, where herbs such as bachelor s button (Cotula coronopifolia), Sellliera radicans and Samolus repens appear on occasional open patches. Marsh ribbonwood (Plagianthus divaricatus), pampas and flax form a broken line along the back of the saltmarsh, although of these species only pampas occurs in the vicinity of the burned area. The flax and pampas is small and stunted, growing to no more than 2m, probably due to saline influence. At the back of the saltmarsh a short distance south of the burned area is a stand of manuka, growing to 5m tall. The oioi and marine rush grades abruptly into a dense sward of Baumea juncea which grows under the manuka, with occasional flax and pampas. A few Hebe 769 Te Pahu Road, R.D.5, Hamilton, New Zealand T: ; F: ; E: info@kessels-ecology.co.nz

2 stricta and Leucopogon fasciculatus shrubs also occur under the manuka, along with small amounts of Isolepis nodosa, and Lotus pedunculatus. Eucalypts and wattle species (Racosperma mearnsii and R. longifolia) are beginning to grow through the manuka and may overtop it in time. Two drains cut through the saltmarsh. The smaller of these runs through the area which has been burned. It is almost stagnant, 30cm across, with a dark, muddy substrate. Previous drain clearance operations have produced a low ridge along the north side which supports a line of small planted pohutukawa (killed by the fire see Section 3.2 and Photo 7) as well as small pampas, wattle and marsh ribbonwood. The larger drain cuts through the manuka stand and is mostly lined with pampas, with smaller amounts of marine rush and Baumea articulata. It drains a nearby industrial area and has a slight oil slick and oily smell. Crab (Helice sp.) burrows dot its muddy banks. 1.3 Causeway Vegetation The vegetation on the causeway was not examined in detail, however a few notes were made. Of greatest significance was the presence of sand tussock (Austrofestuca littoralis), a species listed by the Department of Conservation (DoC) as in Gradual Decline (Brandon et al, 2004). Elsewhere in the Waikato Region it is known from Tairua, Mercury Bay, and near Aotea (Brandon et al, 2004), and from Raglan (pers. obs.). Otherwise, the causeway vegetation is a mix of planted and adventive species, predominantly Spanish heath (Erica lusitanica), Cotoneaster sp., pampas, flax, pohutukawa, rewarewa and grasses. A sun orchid (Thelymitra sp.) is also present. Photo 1. Causeway vegetation. Austrofestuca littoralis on lower left. Note cleared mangrove in foreground 2 Fauna 2.1 Birds At the time of the survey several birds were feeding in the cleared area. These were two Pied Stilts, up to four White-faced Heron, a Kingfisher, two Spur-winged Plover and two Mallard, with a brood of seven ducklings. Other species observed or heard in the immediate vicinity were Variable Oystercatcher, Pied Shag, Black-backed Gull, Red-billed KESSELS & ASSOCIATES LTD 28 NOVEMBER

3 Gull, Fantail, Silvereye, Chaffinch, Greenfinch, Starling, and Blackbird. The area (particularly the manuka stand and adjacent saltmarsh vegetation) appeared to be suitable habitat for North Island Fernbird, although none were encountered. One was heard in similar habitat at the mouth of the Te Weiti Stream on 9 November, and they are known to occur in the saltmarsh on the northern side of the causeway (Grant McIntosh, Gerry Kessels, pers. comm.). North Island Fernbird are listed as sparse" in the DoC threatened species lists. Banded Rail are also likely to be present in the mangroves of the inlet, although none were encountered. Tui are likely to visit the flax one was seen feeding in nearby saltmarsh on 9 November. Photo 2. Pied Stilt on cleared area. 2.2 Reptiles An apparently healthy population of Moko Skink (Oligosoma moco) is present on the causeway. Numerous individuals were sighted sun-basking along the causeway banks immediately above the cleared mangrove area. This species is confined to northern New Zealand and has mostly been recorded from offshore islands, with only a few known mainland populations in Northland, Auckland and the Bay of Plenty (Towns et al, 2002, Gill & Whitaker, 1996). This population had not previously been recorded (Leigh Marshall, pers. comm.) and must be regarded as highly significant. While this species was not recorded away from the causeway it has presumably been present in the area for a long time, pre-dating the mid-20th century construction of the causeway. It is therefore likely that it is more widely distributed, and at least occasionally makes use of surrounding vegetation areas. The shore skink Oligosoma smithi occurs in similar habitats around Whangamata (pers. obs.) and may also be present here. KESSELS & ASSOCIATES LTD 28 NOVEMBER

4 Photo 3. Oligosoma moco on Moana Anuanu Causeway. 2.3 Fish Fish were not formally surveyed, however small schools of yellow-eyed mullet could be seen at high tide swimming through the cleared area, and a grey mullet was seen jumping in the channel. While engaged in other work on the following day (9 November) I observed large schools of inanga, a long-finned eel and a juvenile (60mm) parore in a channel passing through mangroves approximately 1km north of this area these species are likely to be present in the Moana Anuanu Inlet as well. Other species likely to utilise the area include black and yellow-bellied flounder, kahawai, estuarine cockabully and stargazer. The drains through the saltmarsh would be marginal habitat for inanga at best. The upper limits of the saltmarsh, however, would be excellent spawning habitat for inanga, and therefore of significance for the whitebait fishery. Species of freshwater fish recorded in the NIWA Freshwater Fish Database from the Wentworth River, which drains into the Moana Anuanu Estuary, are long-finned eel, redfinned bully, torrentfish, common bully, common smelt and inanga. These are all diadromous species which would have to pass through the inlet to reach their adult habitats. Other freshwater species known from similar streams nearby include short-finned eel, giant bully, blue-gilled bully and banded kokopu. 2.4 Invertebrates The main invertebrates within the mangroves are the snail Amphibola crenata and the crab Helice crassa. Swarms of minute mysid shrimps are present in shallow films of water. The small black mussel Xenostrobus pulex occurs in scattered clumps on the mangrove stems, and the high-spired snail Zeacumantus subcarinatus is mainly confined to the region along the main channel. KESSELS & ASSOCIATES LTD 28 NOVEMBER

5 Amphibola is also quite common in the saltmarsh, although most are quite small. Far more abundant, although inconspicuous because of their size, is the small snail Potamopyrgus estuarinus. Helice burrows are widely scattered. 3 Extent of Fire and Mangrove Clearance 3.1 Mangrove clearance The extent of the cleared mangrove, extent of the fire and other damage are shown in Figure 1. Figure 1. Extent of mangrove clearance (yellow), fire damage (red) and vehicle damage (blue). As well as the mangrove clearance previously identified on the eastern side of the inlet, there have been smaller areas cleared on the western side in the corner between the causeway and the shoreline (about 9 trees cut), and along a sandbank (approx. 160 x 23m and 80 x 20m cleared) see Photo 4. In addition, another area of mangrove clearance (approx. 100 x 30m) was located in the course of other work on 9 November near the mouth of the Waikiekie Stream (see Figure 2). Figure 2. Cleared mangrove (yellow) near mouth of Waikiekie Stream. KESSELS & ASSOCIATES LTD 28 NOVEMBER

6 Photo 4. Clearance on sandbank, western side of inlet. In the main area of cleared mangroves on the Moana Anuanau Inlet, the eastern half has been mown, presumably to inhibit regrowth of the abundant remaining mangrove seedlings. Tractor tracks resulting from this operation were still very obvious. Photo 5. Mown (left) and unmown (right) areas of mangrove clearance. KESSELS & ASSOCIATES LTD 28 NOVEMBER

7 3.2 Saltmarsh fire Mangrove branches had been piled up and left on the unmown section; however on the mown section they had, apart from the heavy basal stumps, been removed to the saltmarsh and burned. Some of these fires were on the boundary between the saltmarsh and the former mangrove area (see Photo 6). These were of limited extent, however another fire which was apparently started on or near some clumps of pampas grass on the upper edge of the saltmarsh spread and ran through an area of oioi and marine rush, damaging an area 105m from end to end and 8-24m across (Photo 7). About seven 1.5m tall pohutukawa, along with a few ribbonwood, small pampas and a couple of small wattle growing along a line of dredgings beside a small drain which cuts through the saltmarsh were killed by this fire. Much of the oioi and marine rush, however, had only been singed, and was already beginning to regrow, although patches up to 3m across appear to have been killed. Photo 6. Site of mangrove fire on boundary of saltmarsh. Area affected by uncontrolled burn in right background (brown). KESSELS & ASSOCIATES LTD 28 NOVEMBER

8 Photo 7. Uncontrolled burnoff through oioi and marine rush damage largely superficial. Dead young pohutukawa in background. Photo 8. Killed oioi and marine rush. KESSELS & ASSOCIATES LTD 28 NOVEMBER

9 The base of the fire was on the bank behind the saltmarsh. This supports a largely exotic vegetation of pampas, Japanese honeysuckle, tall fescue, kikuyu grass, scrambling fumitory, montbretia, cleavers, purple morning glory, blackberry, cocksfoot, wild carrot. The few trees are all exotic eucalypts, matsudana willows and loquat. A few flax bushes are present on the bank but do not appear to have been damaged by the fire. Some of the most serious damage to the saltmarsh wetland has come from digging operations along the base of the bank, presumably to extinguish the fire. An area approximately 51m x 3m has been affected by this. Photo 9. Burned bank. Note dug-over mud and sand. In addition, vehicle traffic in and out of the saltmarsh has crushed oioi and marine rush in the corner adjacent to the end of the causeway. A strip of this vegetation approx. 20m long has also been mown. Photo 10. Vehicle damage to saltmarsh. KESSELS & ASSOCIATES LTD 28 NOVEMBER

10 4 Assessment of Ecological Significance 4.1 Significance Assessment using PNAP Criteria The site has been assessed based on criteria outlined by Whaley et al. (1995), which is summarised as follows: 1. Representativeness 2. Diversity and pattern 3. Rarity/special features 4. Naturalness/intactness 5. Size and shape 6. Inherent ecological viability/long-term sustainability 7. Buffering/surrounding landscape/ connectivity 8. Fragility and threat (threat process and agents, effects of proposed modification) 9. Management input (nature and scale/intervention necessary, restoration potential) Representativeness: The Moana Anuanu Inlet is contained within the Tairua Ecological District (ED No: 10.06). The area concerned lies in the lower (northern) reaches of the Moana Anuanu Inlet, within the town of Whangamata and immediately upstream of a road causeway. It is an estuary with sand and mud flats, the eastern half (and small areas of the western half) of which was until recently colonised by mangroves. A band of saltmarsh approximately 50m wide lies between the mangroves and the shoreline. Leathwick et al (1995) estimated that there was 148ha of saltmarsh left within this ecological district, and 92ha of mangroves, although mangroves have expanded since that time. Within Whangamata Harbour itself aerial mapping estimates indicate that 15.89ha of saltmarsh habitat remains (M. Felsing, pers comm). Diversity and pattern: The area contains three main indigenous vegetation types mangroves, Juncus-Leptocarpus saltmarsh and small-leaved scrub. There is also an area of highly modified exotic vegetation along the north-eastern bank and a scrubby, though floristically unusual, vegetation community along the causeway. Zonation of these communities is well-defined, with very narrow transitional zones. Rarity/special features: No rare plant or animal species were recorded within the saltmarsh or mangroves; however North Island Fernbird and Banded Rail are likely to utilise this habitat. Banded Rail and North Island Fernbird are listed by DoC as Sparse (Hitchmough, 2002). The causeway has two threatened species: the sand tussock Austrofestuca littoralis, listed by Dept of Conservation as in Gradual Decline, and the skink Oligosoma moco, Until recently fewer than five mainland sites for Oligosoma moco species were known (Towns et al, 2002), although another site was found in Auckland recently (NZ Herald, 12 September). As far as I am aware the causeway is a new location for the species. Naturalness/intactness: Prior to the recent clearance operations the mangrove and saltmarsh communities were largely intact, displaying a well-defined zonation from mangrove through saltmarsh to small-leaved scrub. The causeway acts to impede the natural flow of water through the estuary and reduce flushing by tidal action. This may be contributing to the rapid development of black, anoxic, sulphurous-smelling mud following the mangrove clearance. KESSELS & ASSOCIATES LTD 28 NOVEMBER

11 Size and shape: Over most of its length of approximately 1200m, the Moana Anuanu Estuary is approx. 300m across. It is considered of sufficient size and shape to be selfsustaining. Inherent ecological viability/long-term sustainability: The lower catchment of the Wentworth River, which drains into this inlet, has been highly modified by agricultural and urban development, however the upper catchment is still largely forested, so that the overall water quality in the river is quite high. With appropriate management the inlet has the potential to be viable ecologically in the long term. Buffering/surrounding landscape/ connectivity: The estuary has little buffering from the surrounding town, which surrounds it almost entirely. The saltmarsh and mangrove communities, on the other hand, trap sediments and nutrients that would otherwise end up in the wider Whangamata Harbour, though its ability to do this has been compromised by the mangrove clearance. The NIWA Freshwater Fish Database has several entries for the Wentworth River, showing it to have a diverse indigenous fish fauna with several diadromous fish species which would necessarily pass through the inlet to complete their life cycles. Fragility and threat (threat process and agents, effects of proposed modification): Direct human disturbance of the saltmarsh poses the most immediate and direct threat to the remaining saltmarsh areas. Saltmarsh is particularly vulnerable to people walking or driving across it, particularly with heavy machinery. Human disturbance also affects habitat use by birds, fish and invertebrates. Fire is also a very obvious threat. The most serious weed threat in the saltmarsh would be pampas grass, which is already widespread, and likely to spread further into areas cleared by burning. Purple morning glory and montbretia also have the potential to spread further. Other significant weed species, particularly in the manuka, are black wattle and Sydney golden wattle. All of these, however, will be limited in their spread by their intolerance of high salinity within the saltmarsh proper. In the medium term, decay of mangrove roots in the highly enclosed environment behind the causeway is likely to maintain or exacerbate the sulphurous, anoxic state of the sediment in the cleared area, particularly in the north-eastern corner. Management input (nature and scale/ intervention necessary/ restoration potential): Measures to prevent further human intrusion and clearance, mowing and fire impacts on the remaining saltmarsh area is considered to be the most pressing management requirement. Active management will be required to prevent the spread of weeds into areas denuded by the fire. Areas within the oioi/marine rush zone appear to be recovering naturally, however it would be desirable to replant the completely burned out areas along the bank with appropriate indigenous species such as flax, karamu, manuka, Hebe stricta or, in more saline areas, marsh ribbonwood, bachelor s buttons, Selliera radicans or Samolus repens. 4.2 Significance Assessment using EW RPS Criteria The assessment of the ecological sensitivity (significance) of the study area was undertaken using Environment Waikato s Proposed Regional Policy Statement criteria for assessing sites of significant indigenous vegetation and habitats of indigenous fauna (Denyer & Shaw, 2002). Tables 1 and 2 assess the area with regard to the EW Regional Policy Statement Criteria for assessing ecological significance. In summary, Whangamata Harbour as an entire ecosystem can be ranked as of National Significance because of its relative intactness, and the diversity of intact estuarine communities it contains, which in turn provide habitat for a number of nationally threatened indigenous species, such as NZ dotterel. To this end the KESSELS & ASSOCIATES LTD 28 NOVEMBER

12 Waikato Regional Coastal Plan recognises the Upper Whangamata Harbour as an Area of Significant Conservation Value (EW, 2001). When considered as a discrete ecosystem, the saltmarsh and mangrove communities within this part of the Moana Anuanu Estuary are considered to be of Regional Significance. While they are good representations of intact and diverse saltmarsh and mangrove habitats, they do not appear to support habitat for acute or chronically threatened fauna and flora species. However, the presence of the critically threatened sand tussock on the adjacent causeway is of particular note and does suggest that sand tussock may have been present in the burnt-off areas of saltmarsh. The moko skink is also highly likely to utilise the shore-margin vegetation along the edge of the saltmarsh. Table 1: Assessment of the Site against Environment Waikato RPS Criteria for Significant Indigenous Ecosystems Specific Criteria 1 It is indigenous vegetation or habitat that has been specially set aside by statute or covenant for protection and preservation, unless the site can be shown to meet none of Criteria NO 2 It is indigenous vegetation or habitat recommended for protection by the Nature Heritage Fund or Nga Whenua Rahui committees, or the Queen Elizabeth the Second National Trust Board of Directors, unless the site can be shown to meet none of Criteria 3-11 NO 3 It is vegetation or habitat that is currently habitat for indigenous species or associations of indigenous species that are: threatened with extinction, or endemic to the Waikato Region YES, Austrofestuca and moko skink are scarce and/or declining 4 It is indigenous vegetation or habitat type that is under-represented (10% or less of its known or likely original extent remaining) in an Ecological District, or Ecological Region, or nationally. YES, saltmarsh is under-represented in this ED. 5 It is indigenous vegetation or habitat that is, and prior to human settlement was, nationally uncommon, such as geothermal, Chenier plain, or karst ecosystems. NO 6 It is wetland habitat for indigenous plant communities and/or indigenous fauna communities 1 that has not been created and subsequently maintained for or in connection with: waste treatment; or wastewater renovation; or hydro electric power lakes 2 ; or water storage for irrigation; or water supply storage; unless in those instances they meet the criteria in Whaley et al. (1995). YES, is natural estuarine wetland 7 It is an area of indigenous vegetation or naturally occurring habitat that is large relative to other examples in the Waikato Region of similar habitat types, and which contains all or almost all indigenous species typical of that habitat type. NO 8 It is aquatic habitat that is a portion of a stream, river, lake, wetland, intertidal mudflat or estuary, and their margins, that is critical to the self sustainability of an indigenous species within a catchment of the Waikato Region and which contains healthy, representative populations of that species. YES important inanga spawning habitat, several diadromous species pass through it to complete their life cycles. 9 It is an area of indigenous vegetation or habitat that is a healthy, representative example of its type because: its structure, composition, and ecological processes are largely intact, and if protected from the adverse effects of plant and animal pests and of adjacent landuse (e.g. stock, discharges, erosion), can maintain its ecological sustainability over time. YES, although it has been adversely affected by mangrove clearance. 10 It is an area of indigenous vegetation or habitat that forms part of an ecological sequence that is either not common in the Waikato Region or an ecological district, or is an exceptional, representative example of its type. YES, wetland areas are contiguous with Whangamata Harbour and Wentworth River and are uncommon locally and nationally 11 It is an area of indigenous vegetation or habitat for indigenous species (which habitat is either naturally occurring or has been established as a mitigation measure) that forms, either on its own or in combination with other similar areas, 1 2 Does not include exotic rush/pasture communities. Does not include Lake Taupo. KESSELS & ASSOCIATES LTD 28 NOVEMBER

13 an ecological buffer, linkage or corridor, and which is necessary to protect any site identified as significant under Criteria 1-10 from external adverse effects. YES important buffer for adjacent mudflat and harbour, part of corridor for fish and bird movement along Wentworth River. Table 2: Checklist for Assessing Relative Importance of an area of Significant Indigenous Vegetation or Significant Habitat of Indigenous Fauna (Green highlighting indicates compliance) Crit. Reason for Significance Levels* Significance* International National Regional 1 Legally protected RAMSAR or WHS Ecological Area, Forest Sanctuary, National Park, Marine Reserve, Nature Reserve, Scientific Reserve 2 Recommended for protection 3 Threatened species Waikato Endemic species As a RAMSAR or WHS Acutely threatened species that are endemic to the Waikato As an Ecological Area, Forest Sanctuary, National Park, Marine Reserve, Nature Reserve, Scientific Reserve SSWI site of high value Acutely or chronically threatened species- sand tussock Other Reserves Act or Cons. Act. or a QEII covenant WMR- DoC As another reserve type under Reserves Act or Cons. Act. or a QEII covenant Ranked as a KES 82 At risk threat category, range restricted or sparse moko skink. International migrants that would be threatened if habitat was lost Non-threatened Waikato endemic Good quality example of regionally under-represented site (must also meet Crit. 9) estuarine wetland 4 Under-represented ecosystem Best*** or only remaining, large example of a suite or sequence of ecosystems. (For criteria 4, 5, 6, and 10, sites in this category would also be likely to meet a number of other criteria and form a complex of ecosystems.) Good quality example of nationally under-represented site (must also meet Crit. 9) Relatively large but degraded example of nationally underrepresented site Degraded, but Region s only remaining example (of any size) 5 Nationally uncommon ecosystem Best*** or only remaining large example in NZ of a suite of ecosystems 6 Wetland habitat Best*** or only remaining large example in NZ of a wetland type 7 Large example of wildlife habitat ** Good quality example of a nationally rare type (must also meet Crit. 9) Good quality example (must also meet Crit. 9) estuarine wetland Relatively large but degraded example Relatively large but degraded example See notes below** See notes below** Good quality representative example (must also meet Crit. 9) 8 Aquatic habitat ** See notes below** See notes below** The Region s best or only example of a good quality example (must also meet Crit. 9) 9 Representative example** 10 Uncommon or exceptional ecological sequence See notes below** See notes below** One of the Region s best examples Best*** or only remaining large example of a suite or sequence of ecosystems Good quality example of a nationally rare ecological sequence (must also meet Crit. 9) One of the Region s best examples (must also meet Crit. 9) 11 Buffer - - Buffers a site that is of national or international significance Notes for Table 3 If a site is not of international, national, or regional significance, but meets one of the 11 criteria, it is locally significant. * Levels of significance are applicable to any site that is part of a larger area that qualifies under any criterion. ** A site that is significant as a large area of wildlife habitat, aquatic habitat or a representative example of its type, will only be of greater than regional significance if it also meets one of the other criteria for which national or international levels apply. For instance, if the site was also habitat for acutely threatened species, it would be assessed using Criterion 3 as well as Criteria 7, 8, or 9. *** Sites that are the best example of their type will also meet Criterion 9. For international significance such sites will also be likely to meet a number of other criteria and must form a complex of ecosystems. KESSELS & ASSOCIATES LTD 28 NOVEMBER

14 5 Summary of Impacts 5.1 Impacts on vegetation A total of 1726m 2 of saltmarsh was burned, but of this only a few square metres was killed outright; the rest has been only singed and should recover rapidly. Areas of killed oioi and marine rush will probably be recolonised by those species eventually, as the saline conditions are unfavourable for most weeds. Because the underlying hydrodynamic and geomorphologic conditions which have promoted saltmarsh in this area have not been altered by the fire and vehicle damage, re-establishment of the key saltmarsh species oioi and marine rush is expected to occur relatively quickly. Whereas mangrove communities are flooded at each high tide, saltmarsh communities are generally only flooded by brackish waters during the highest spring tides and thus occupy a very and specific niche within estuarine ecosystems. Saltmarsh vegetation crushed by vehicles will probably recover naturally over the next few months provided no further intrusion or fires occurs. Further damage by vehicle access is of concern as over-compaction of the sediment materials may make re-colonisation by saltmarsh plants (and invertebrate species) more difficult. In addition, continued fire events and compaction may exacerbate colonisation of the saltmarsh habitat by mangroves, by changing tidal hydrology and sediment deposition rates, as well as allowing space for the establishment of mangrove propagules. The area of approx. 150m 2 which was dug over at the base of the bank, presumably to extinguish the fire, will take longer to recover, and is likely to be colonised by weeds (probably pampas) as it is less saline. It would be desirable if this area could be replanted as outlined above (Section 4.1). Terrestrial shoreline vegetation (such as the small pohutukawa which grew alongside the small drain) should also be restored by an intensive replanting programme using appropriate locally sourced indigenous species. Ongoing weed control within the saltmarsh area and margin will be required. 5.2 Impacts on fauna The extent and severity of the impact of habitat damage on wetland birds, fish and estuarine invertebrates is difficult to assess exactly because of the role of density-dependent factors, animal mobility and in this case lack of quantitative information. Nonetheless, worldwide studies of habitat loss or reduction in habitat quality has been shown to impacts by: reducing both the abundance of fauna using a site; reducing primary productivity of the degraded areas; causing a loss of important breeding habitat and refugia for invertebrates or juvenile fish; and at the population level, changing mortality and productivity rates. The most significant animal species which are likely to have been impacted by the fire would be fernbird, which forage in low saltmarsh vegetation similar to that which has been burned (pers. obs.), and inanga, which spawn in marginal estuary vegetation (McDowall, 2000). Invertebrates (mostly Helice, Amphibola and Potamopyrgus) appear to have come through relatively unscathed, other than in small patches where everything has been burned. KESSELS & ASSOCIATES LTD 28 NOVEMBER

15 Nonetheless, given the expected ability of the majority of the damaged saltmarsh to recover and the extent of similar available habitat in proximity, it is my opinion that in the absence of any further disturbance, combined with suitable weed control and replanting, the effects of the saltmarsh burning and damage within this site on indigenous fauna species will be temporary. 5.3 Monitoring Monitoring will be required to assess: 1. The recovery of saltmarsh plants; and 2. Weed intrusion A suitable monitoring programme should be designed as soon as possible. Details of scientifically robust wetland monitoring techniques can be found in the following publication: Clarkson BR, Sorrell BK, Reeves PN, Champion PD, Partridge TR & Clarkson BD 2003, revised edition 2004 Handbook for Monitoring Wetland Condition, A Ministry for the Environment Sustainable Management Fund Project. Yours faithfully David Riddell MSc (hons 1) Ecologist, Kessels & Associates Ltd KESSELS & ASSOCIATES LTD 28 NOVEMBER

16 6 References Brandon, A.; de Lange, P.; Townsend, A. 2004: Threatened Plants of Waikato Conservancy. Dept of Conservation, Wellington. 92p. Denyer, K.; Shaw, W. 2002: Areas of Significant Indigenous Vegetation and Habitats of Indigenous Fauna in the Waikato Region Guidelines to apply regional Criteria and Determine Level of Significance. Environment Waikato, Hamilton Environment Waikato Proposed Waikato Regional Coastal Plan. Hitchmough (compiler). 2002: NZ Threat Classification Lists. Threatened Species Occasional Publication 23, Department of Conservation, Wellington. Gill, B.; Whitaker, T. 1996: New Zealand Frogs and Reptiles. David Bateman, 112p. Leathwick, J. R.; Clarkson, B. D.; Whaley, P. T. 1995: Vegetation of the Waikato Region: Current and Historical Perspectives. Landcare Research Contract Report: LC9596/022. Environment Waikato. McDowall, R. M. 2000: The Reed Field Guide to New Zealand Freshwater Fishes. Reed, Auckland. 224p. Towns, D. R.; Neilson, K. A.; Whitaker, A. H. 2002: North Island Oligosoma spp. Recovery Plan. Threatened Species Recovery Plan 48. Dept of Conservation, Wellington. 62p. Whaley, K. J.; Clarkson, B. D.; Leathwick, J. R. 1995: Assessment of criteria used to determine significance of natural areas in relation to section 6(c) of the Resource Management Act(1991). Unpublished Landcare Research Contract Report LC9596/021 to Environment Waikato. 34 p. KESSELS & ASSOCIATES LTD 28 NOVEMBER