THE MERSEY GATEWAY PROJECT (MERSEY GATEWAY BRIDGE) AVIAN ECOLOGY SUMMARY PROOF OF EVIDENCE OF. Paul Oldfield

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1 HBC/14/3S THE MERSEY GATEWAY PROJECT (MERSEY GATEWAY BRIDGE) AVIAN ECOLOGY SUMMARY PROOF OF EVIDENCE OF Paul Oldfield 1

2 1 DESCRIPTION OF THE BIRDLIFE IN THE UPPER MERSEY ESTUARY LOCAL WILDLIFE SITE 1.1 The description of the birdlife is based around a large amount of data collected in the field and through data compiled by WeBS, The Wetland Bird Survey counts. For reasons connected to the international designation of the Middle Mersey Estuary, there has been a concentration on seven bird species Sheduck, Teal, Golden Plover, Redshank, Dunlin, Pintail and Balck-tailed Godwit. 1.2 In addition, other survey work has been carried out on summer nesting breeding birds and other resident birds such as Skylark, Meadow Pipit and Reed Bunting, and updated through published sources. This information is connection with the local designation of Local Wildlife Sites in Halton. 1.3 Using the bird count data, and through an understanding of bird ecology, an evaluation of the birdlife features within the Upper Mersey Estuary supports the local designation as a Local Wildlife Site. 1.4 A Projection is made for the birdlife in the Upper Mersey Estuary LWS. It concludes the birdlife, including breeding, feeding, roosting and visiting species, is unlikely to change significantly over 10 to 30 years. 2

3 2 DESCRIPTION OF THE BIRDLIFE IN THE MIDDLE MERSEY ESTUARY (SPA, EUROPEAN MARINE SITE, RAMSAR SITE AND SSSI). 2.1 A key aspect of the Mersey Gateway project is to assess its impact on the Special Protection Area (SPA) part of the Mersey Estuary. 2.2 The SPA attracts the wildfowl and waders in large numbers for several reasons as summarised below: 1. The SPA is very large and sheltered, and it contains extensive areas of intertidal silt and mud habitats, the majority of which are free from disturbance. 2. The extensive areas of intertidal sand and mudflats are rich in invertebrates which provide an abundance of prey. 3. There are extensive areas of grazed saltmarsh with associated creeks and pools, providing an abundance of accessible invertebrate prey and plenty of palatable plant food. 4. The topography of the saltmarsh habitat allows the birds to feed whilst having an all-round and unobstructed field of view which enables them to see predators approaching from a distance, giving the birds time to take flight. 5. The SPA also provides sufficient roosting habitat for the wildfowl and waders so that they are able to roost near their feeding habitats. 2.3 According to the most data, the SPA regularly supports six of the seven relevant species at internationally important levels, with only Pintail numbers no longer meeting the international threshold. In conclusion, the Middle Mersey Estuary still qualifies for SPA and the associated designations but some of the bird populations are exhibiting increasing or decreasing trends. 3

4 2.4 A Projection is included in the Proof of Evidence. It concludes there is likely to be very little change in the extent and ecological condition of the different habitats in the Middle Mersey Estuary and SPA, and the relative amounts of saltmarsh and other intertidal habitats are unlikely to change significantly over the next 30 years, although their positions may alter geographically. 4

5 3 CONSIDERATION OF THE ECOLOGICAL RELATIONSHIPS OF THE UPPER MERSEY ESTUARY LWS AND THE MIDDLE MERSEY ESTUARY SPA 3.1 It is concluded that it is correct that the Upper Estuary is not designated as an SPA because: - 1. It does not support the required numbers of wintering and migratory wildfowl and wading birds. 2. Its wintering and migratory bird populations are not the same as those in the SPA. 3. Although the Upper Mersey Estuary is a natural extension of the Middle Mersey Estuary, its bird populations are not natural extensions of the Upper Mersey Estuary populations; therefore there is no connectivity in terms of bird populations. 4. Because there is no bird population connectivity between the SPA and the Upper Mersey Estuary, and no functional relationship, it can be concluded that any change in bird species and bird population sizes in the Upper Mersey Estuary will not affect the integrity of the Middle Mersey Estuary SPA. 5. There is an absence of suitable roosting sites. 6. There are clear-cut ecological reasons for the absence of bird population connectivity and lack of any functional relationship, these being the relatively poor food resource in the Upper Mersey Estuary both absolutely and compared with the SPA. 5

6 4 ASSESSMENT OF CONSTRUCTION AND OPERATIONAL EFFECTS OF THE NEW BRIDGE ON THE UPPER MERSEY ESTUARY LOCAL WILDLIFE SITE (LWS) CONSTRUCTION EFFECTS 4.1 Disturbance to birds during construction of the new Bridge can be the result of a variety of different activities. The extent of the disturbance is determined to be within a 300 metre corridor either side of the New Bridge. 4.2 Disturbance of wildfowl and wading birds in the Upper Estuary will cause them to move elsewhere in the Upper Estuary or downstream into the Middle Estuary SPA, or outside the estuary, away from disturbance. 4.3 The bird count data for the wintering birds shows very small mean numbers of all individual species within the 300 metre corridor within the Local Wildlife Site. Of the SPA species, Pintail and Black-tailed Godwit are absent, extremely low for Redshank, and low for Dunlin. For Shelduck, the figures are very low on the saltmarsh and tidal waters, and low for the Intertidal mud and sands, of which there is an abundance elsewhere in the LWS 4.4 The construction period will have an effect on other birdlife, in particular summer breeding birds that build their nests on or near the ground such as Skylark, Meadow Pipit and Reed Bunting. Within the 300 metre disturbance zone, the effect is likely to be minimal due to the regular use of access tracks for construction traffic and zoned off areas where the contractor will not be able to enter, and by careful timing of the works and pre start land management to prevent nesting occurring within the corridor. 4.5 The use of piled jetties instead of stone access roads in the intertidal areas, beyond the salt-marshes, will disturb birds such as Shelduck and wading birds that feed in these habitats. 6

7 4.6 The presence of temporary structures (e.g. towers and cranes) and the developing bridge structure will leave plenty of gaps through which birds can fly, and birds flying above or beneath the structures can easily avoid such obstacles. 4.7 An assessment has been made of the constructional effects on birdlife at Wigg Island LNR. Construction disturbance will inevitably affect breeding and other birds as a result of movements of machines and delivery of construction activities. OPERATION EFFECTS 4.8 Disturbance to birds after construction and during use of the new Bridge will be caused by the presence of the bridge structure and by traffic movements over the bridge. There will also be effects of noise and lights of moving traffic after construction, and artificial lighting of the bridge at night may have effects. 4.9 There will be reduced disturbance of wildfowl and wading birds compared with that during construction because there will be no activities on the saltmarshes or on the intertidal habitats The limit of disturbance after habituation is likely to be significantly closer to the new Bridge than the 300 metres considered for the construction period. However, a precautionary approach has been adopted and an operational disturbance limit has been fixed at 200 metres on either side of the new Bridge. This will create a 28.5 hectare saltmarsh nature reserve to be managed for its bird interest By looking at the actual bird data for this 200m corridor, the same conclusions are drawn as for the 300m corridor during the construction period. Very small numbers of all individual species are affected. 7

8 4.12 An assessment of the operational effects of the New Bridge on Wigg Island concludes that traffic movements and associated noise are expected to disturb woodland canopy bird species but there will be significant habituation. 8

9 5 ASSESSMENT OF THE CONSTRUCTION AND OPERATIONAL EFFECTS OF THE NEW BRIDGE ON THE EUROPEAN SITE (SPA) IN THE MIDDLE MERSEY ESTUARY 5.1 There will be no disturbance to breeding, feeding, roosting and loafing birds in the Middle Estuary SPA because construction work in the Estuary will be entirely within the new Bridge corridor in the Upper Estuary. The Middle Estuary will remain undisturbed and will not be used for access by machinery and materials. 5.2 The wildfowl and wading bird communities of the European Site and those of the Upper Mersey Estuary are separate populations. There are no significant movements of birds other than gulls between the two parts of the Estuary. Therefore construction of the new Bridge, because it will be restricted to the Upper Estuary and will be distant from the bird populations in the Middle Estuary SPA, will not affect commuting and migrating birds using the European Site. 5.3 The presence of the new Bridge structure, being outside the SPA and well beyond the possible bird disturbance zone of 200 metres, will have no disturbance effect on birds using the SPA. This also applies to traffic use of the new Bridge. Traffic noise, traffic movements and lighting effects will be insignificant because of the distance of the new Bridge from the SPA. 9

10 6 MITIGATION OF THE EFFECTS OF CONSTRUCTION AND OPERATION OF THE NEW BRIDGE ON THE LOCAL WILDLIFE SITE IN THE UPPER MERSEY ESTUARY 6.1 The mitigation objectives for the Upper Estuary are to improve the values of the Widnes Warth and Astmoor saltmarshes in close proximity to the New Bridge so that wildfowl and wading birds are encouraged to use those areas for feeding and roosting, despite the presence and use of the New Bridge and despite the permanent losses of saltmarsh and other intertidal habitat following pier and tower construction. This can be achieved by raising the quality of the adjacent saltmarsh habitat, the extent of which has been chosen as 200 metres either side of the New Bridge. This will have the effect of creating an area of hectares of saltmarsh capable of being managed to nature reserve standard. 6.2 All of the mitigation work for bird species will be on habitat management. For the construction period, the key actions are:- 1. There will be installation of fences where necessary to protect the saltmarshes from disturbance by people and dogs. 2. Shooting rights on the estuary edge to the saltmarsh mitigation areas have been extinguished within the 300 metre construction corridor. 6.3 For the operational period:- 1. There will be management of the cut saltmarsh vegetation by conservation cattle grazing and grass cutting to convert the vegetation to a range of saltmarsh plant communities known to be favoured by feeding and roosting wildfowl and wading birds, 2. Saltmarsh scrapes and pools will be created in close proximity to the bridge alignment 10

11 3. There will be maintenance and upgrading of the construction period fenceline to protect the saltmarshes from disturbance by people and dogs. This will help to protect ground nesting birds during the breeding season, as well as providing sanctuary in winter for wildfowl and wading birds. 4. Shooting rights on the saltmarsh mitigation areas that were extinguished within the 300 metre construction corridor, will be allowed back to within 200 metres of the New Bridge during the operational period. 6.4 It is proposed that ecological monitoring be undertaken prior to, during and after construction of the Project. 6.5 It is anticipated that a Mersey Gateway Environmental Trust will be established under the Charities Act This Trust will be the vehicle through which the mitigation outlined above for the Upper Estuary will be delivered. The exact workings of this Trust are subject to confirmation; however, it is likely that the Trust will also be involved in the delivery of wider long-term nature conservation initiatives within the Mersey Estuary 11

12 7 ASSESSMENT OF IN-COMBINATION EFFECTS AND APPROPRIATE ASSESSMENT 7.1 There will be no in-combination effects because the Mersey Gateway Project will not cause direct disturbance because it is outside the Middle Mersey Estuary. 7.2 The ES concludes the New Bridge does not significantly adversely effect a European Site, and as such an Appropriate Assessment is not required. However, a shadow exercise has been carried out. The Shadow Appropriate Assessment shows that there will be no significant adverse effects on the Upper Mersey Estuary after mitigation. 8 CONCLUSIONS OF MY EVIDENCE 8.1 I have set out my conclusions in section 13 of my proof of evidence. 12