Wallasea - a wetland designed for the future

The RSPB’s wetland creation project at Wallasea Island in Essex has been much in the news over the last year.  In July, the first phase of the intertidal habitat was completed and the sea wall breached.  On completion of all five phases of this innovative and forward-looking project, around 700 hectares of saline to fresh water habitats will have been created.

The project aims to combat the threats from climate change and coastal flooding by recreating a wetland landscape of mudflats and saltmarsh, lagoons and pasture.  It will also help to compensate for the loss of tidal habitats elsewhere. Habitat design will look to accommodate colonizing species from the south.  Much of this design is difficult to see at ground level but the aerial photograph above shows many of the habitat features incorporated into the design.  This is what can be seen:

A – This will be the visitor hub in the future.  Immediately adjacent are three shallow saline lagoons that will be managed for passage and breeding waders (top photo below).  They will be rotationally dried and flooded to maximize their food supply.  They will provide ideal conditions for Black-winged Stilts.

B – The entrance to the reserve will be through an area of saltmarsh saline creaks with shallow pools, suitable for a range of specialist invertebrates.

C – Shallow saline lagoon with islands and seasonal brackish pools suitable for breeding birds and a range of characteristic flora and fauna.  The conditions will be suitable for species currently more frequent to the south and that are likely to move northwards.

D – Seasonally drying salt pan, for Kentish Plovers with a bit of luck.

E – Freshwater marsh and grassland with pools and ditches for breeding waders.  These areas will be protected from mammalian predators by a barrier fence built into the surrounding ditches (see photo below).

F – Rough grass and wild-bird cover around the margins of the wetland will provide habitat for small mammals, reptiles and invertebrates.  The photo shows the mosaic cutting pattern to increase the structural diversity of the rough grassland. This will also benefit birds of prey such as harriers and owls.

G – An area of regulated tidal exchange with numerous islands, where water levels can be controlled (see sluice photo below) for the benefit of breeding, passage and wintering waterbirds.

H – The inter-tidal area has numerous features designed into it, including shallow lagoons that will provide the ideal feeding conditions and food resource for Spoonbills.  Once fed-up and in the mood, higher islands with scrub have been provided for the Spoonbills for nesting.

I – The range of islands provided includes some with shingle, sand and cockle-shells for nesting terns (hopefully Little Tern) and Ringed Plovers.  Will it all work?  We shall see.

Planning for waders

Don’t you love it when a plan begins to come together?  In the past week I have visited two new sites in development and both look to be full of potential.  First up, Bowers Marsh in South Essex.  Four years into the development, the initial ballpoint pen sketch plan is coming to life on the ground.  This has a wetland design with a nod to the future.  A freshwater lagoon ‘reservoir’ is designed to provide wadery habitat as it feeds the nearby wet grassland areas. A regulated tidal exchange provides a mix of fresh and brackish habitat.  Black-winged Stilt was always a target bird here and the recent arrival of a pair may not be the birding highlight of the month but is another milestone for the site. The briefness of their stay probably reflects the still raw nature of the site.  However, the lagoon islands held 80+ Avocets, Redshank, Lapwing, Ruff and Black-tailed Godwit during my visit, with the highest site count for B-t Godwit already up to a remarkable 1,500 birds.  At the moment this is still a gull-lovers paradise as thousands of birds drift down from the adjacent Pitsea tip to wash and brush up.  Remember the name ‘Bowers Marsh’ and look up how to get there, you will need to go.

The second site was Middleton Lakes in Staffordshire, where a re-design of the wetland habitat has been completed. The omens were good in November 2012 as we visited to check the ongoing works.  A White-rumped Sandpiper became the second species of wader on the ‘new’ scrape.  Although it promptly departed southwards over the county boundary to become a new bird for Warwickshire, it returned to hang around long enough for everyone to catch up with it.  The completed habitat will benefit from linkage to the adjacent river.  At times this will result in some inconvenient floods but overall this dynamic water regime should be beneficial in helping Middleton Lakes continue to develop into a major wader site for the midlands.

Above - Bowers Marsh; from sketch to reality (I didn't have a blue pen), below - Middleton Lakes ditto.

Raise you ten.

Good and bad; Redshank chick and cracked mud.

Another dry spring is upon us and breeding waders in wet grasslands are suffering; site after site is baked hard and cracked. Teeth are sucked and heads are shaken. “Not much we can do – it’s a dry spring” are the usual comments. Quickly followed by “And predation is really bad this year”.

Well, it is surely no surprise that the two are linked.  Drier habitats result in poorer feeding opportunities for waders and allow mammalian predators easier access to the nests and chicks.  Overall, more are predated. With very dry springs, breeding bird numbers crash as waders such as Snipe, and duck, seem to give breeding a miss.  I’ve looked at a dozen or more sites this spring and those that are performing well (and appear to have less predation problems) are those that remain wet.  So the key is to get the habitat into top condition.

But we've now had several dry springs in succession. There is a lot of talk a lot about climate change, how this might affect wetland reserves and what we can do about it.  The simple answer is that we need to adapt our management to these changing conditions and one solution is to store more winter rainfall where possible.  If just an extra 10 cm of water is held in pools or floods at the end of the winter, what difference would it make?  Well, if it were a breezy, sunny April, up to 5 mm of water may be lost through evapo-transpiration on the warmest of days.  So, on average, an additional 10 cm of water is likely to provide an extra month of wetness and this could make all the difference to breeding birds.  One reserve I looked at had put extra water on ‘by accident’ in one compartment.  It was the best looking area on the site and had a high concentration of breeding birds.  Many sites seem overly cautious about raising winter water levels and even let excess water run away.  Climate change is upon us, we need to be more adaptable and one action is to store more rainfall when it is delivered.