Thinking Dutch on flood defence

The Dutch think big! Why can’t we do the same?  A short trip over to The Netherlands for a meeting with the Dutch Birdlife partner Vogelbescherming Nederland (VBN) was a suitable excuse for a couple of site visits. First on the itinerary was a Black-tailed Godwit hotspot at Eemland where 200+ pairs nest on a typically open, wet meadow habitat.  Godwits are increasingly restricted to nature reserves where high water levels are maintained and this reserve is a great example of management for meadow birds.

Continuing north, we came to our main destination outside of the town of Groningen where a massive total of 3,000 ha of wetland habitat has been created as a flood defence scheme for the town.  The waters of the local rivers flow north towards the Wadden Sea.  Historically the low areas around Groningen supported a large peat bog habitat.  Attempts to drain the area started in the Middle Ages and the last 100 years has seen the area managed as pasture.  However, Groningen has a history of serious flooding when river levels have been high.  The local water board Noorderzijlvest looked for a flood defence area, a 'washland', in order to protect the town.  They concluded that the area to the south west of Groningen called De Onlanden area was most suited to fit their requirements. The area was mainly under the control of farmers or conservation organizations. A partnership of organisations was formed and in 2009 the new flood defence scheme was initiated. 

There are two main areas that we looked at: De Onlanden and an area near Zuidlaardermere.  Flood waters are stored in these areas to various depths of up to 1m.  How is this different from washlands in the UK? The key factor is there is an agreement that a level of water is retained into the spring, creating fen, reed and open water habitats.  This brings a win-win situation; flood storage and wildlife-rich wetland habitat. And wow, is this a win for wildlife. 250+ pairs of Black-necked Grebes, breeding Whiskered and White-winged Black Terns, 16 booming Bitterns, Corncrake, Baillon’s, Little and Spotted Crake, 120 prs of Bluethroat, 100prs of Grasshopper Warblers and 150 prs of Marsh Warbler. But this area is not just for wildlife; it is now extensively used by local people for cycling, walking, fishing etc.


In the UK we have numerous washlands, but none deliver like De Onlanden, ours are drained down in the name of maintaining storage capacity. Why can’t we think big and imaginatively like the Dutch?

The road to Utopia

The Wadden Sea islands in The Netherlands are remarkable for both migrant and breeding birds. Texel, at the southern end of the chain is perhaps the best known of the islands and has high levels of conservation management. In 2010 the Dutch conservation organisation Natuurmonumenten created a new nature reserve on Texel. The reserve is a 28 ha brackish lagoon behind the seawall adjacent to the Wadden Sea. Formerly a grass field in agriculture, the land was excavated to create a series of islands in a shallowly flooded lagoon. Around 84,000 m³ of soil was removed and 2,000 m³ of cockle shells brought in to cover some of the islands, which were a mix of grass, shell and mud. Seawater can enter the lagoon at high water via a sluice.

We visited Utopia in 2011 and were duly impressed. The site already supported good numbers of breeding Common (600 pairs), Arctic (60) and Little Terns (54), Avocets (73) and Ringed Plovers (10). Black-headed Gulls (200 pairs), Black-tailed Godwit, Oystercatcher, Lapwing, Redshank and Eider also breed. Spoonbills feed in the lagoon and passage and wintering waders use the lagoon for both roosting and feeding. Terns and other seabirds have a distinct advantage on Texel; the island has virtually no mammalian predators apart from a few Stoats. This was evident at our first stop; a Sandwich Tern colony of some 1200 pairs, easily accessible by ground predators but with hundreds of chicks. Even crows seemed scarce, apparently kept in check by the resident Goshawks.

This type of habitat is sadly lacking in the UK, with coastal habitats under severe pressure from human activities and sea level rise.  However, we are now well on the way to creating our own ‘Utopias’. The first, an 18 ha freshwater lagoon on the Suffolk coast will be excavated and functioning by the end of the year.  The project will excavate 16000 m³ of soil and create a mosaic of grass, bare mud and islands topped with 2000 m³ of shingle for nesting and roosting birds. The site will have an anti-predator fence around the perimeter.  More to follow but in the meanwhile...this is the Dutch Utopia.

The Baillon’s – my part in its finding

After a trip to The Netherlands last summer, I drafted a blog about finding Baillon’s Crake in the UK this year.  I never posted it as it seemed a bit extreme.  What do you know?

In The Netherlands, we looked at some sites created for Purple Herons.  Extensive, shallow wetlands that provide good feeding conditions and will slowly colonise with reed and other aquatic vegetation.   Such areas, of course, attract many other species.  In the early stages, Black-necked Grebes and Spoonbills are likely to appear, but of particular interest was the occurrence of Spotted and Baillon’s Crakes in grassy and rushy habitats after initial flooding.  Bailllons Crakes occur across the Netherlands in low numbers but are very easy to miss and are thought to be more numerous than the figures suggest.  Looking at one of the sites with Baillon’s Crake reminded me of the singing bird in 1999 at Grove Ferry in the early stages of the reedbed habitat creation there.   With only four UK breeding records, are we over-looking them?   Could we manage sites like Grove Ferry to attract more crakes?  A tenner says we could.

Anyway, we decided to add Baillon’s Crake to the national Spotted Crake survey this year. Everyone laughed of course.  Now a Baillon’s has been found on a Spotted Crake survey by Ian Hawkins at Malltraeth.  How many more are out there?

Baillon's typically turns up later in spring in The Netherlands than Spotted; from mid-May until the end of July.  They can breed very late in the season, and have been seen with small chicks in mid-August. The males rattling song, somewhat like a cross between a frog and a Garganey, is best heard during quiet, windless nights.  They may call during rather cold nights, when the Marsh Frogs keep quiet, which is a distinct advantage.  They occupy sometimes surprisingly small marshes with a water table of 10-20 cm, with a vegetation of narrow-leaved marsh plants (typically sedges and low rushes).  When they have young, they will give harsh Magpie-like calls like cha-cha-cha-cha but also loud Blackcap-like ‘tek’ calls.

The Dutch Baillon's site we looked at:

Wallasea

Top two - Wallasea present.  Lower two - Wallasea future? (Tiengemeten)

A trip out to Wallasea Island in Essex this week reminded me of a visit to The Netherlands earlier this year. The Wallasea Island ‘Wild Coast project’ is a landmark conservation and engineering scheme for the 21st century, on a scale never before attempted in the UK. The aim of this project is to combat the threats from climate change and coastal flooding by recreating the ancient wetland landscape of mudflats and saltmarsh, lagoons and pasture. It will also help to compensate for the loss of such tidal habitats elsewhere in England.

Although the Wallasea project may be the largest of its kind in this country, the Dutch are ahead of us in this sort of restoration. In the summer, I visited the island of Tiengemeten in South Holland and had a glimpse of what Wallasea may come to look like in the future.  The project at Tiengemeten was undertaken as part of a programme to restore 3,000 ha of tidal areas in the Dutch Delta region, itself part of the wider Dutch Ecological Networks Plan to create 160,000 ha of ecological networks. Tiengemeten extends to 1,000 ha and was formed as agricultural land claimed from saltmarsh. Now it is being returned to near-naturally functioning habitat. The island has been divided into three zones. The Wilderness zone covers 700 ha and is ex-arable land now open to the influence of the tides and water regimes of the island. The Richness zone (250 ha) is a landformed area of shallow flooding, reedbed and scrub, wet in winter, drier in summer. Finally, the Cultural zone (50 ha) is made up of a campsite, a cafe and a few houses and cropped fields. Grazing by Highland cattle is the primary management tool.

The island was officially given back to nature in 2007 after it was purchased by the Dutch Government. In 2008, a full breeding bird survey was undertaken. The results included the following totals (pairs): 87 Bluethroat, 125 Avocets, 4 Black-winged Stilts, 151 Marsh Warblers, 18 Black-tailed Godwits, 11 Garganey, 3 Spotted Crakes, 3 Goshawk, 1 Corncrake and 612 Greylag Geese. Another full survey was undertaken this year and the results are awaited with interest.

Meanwhile, back on Wallasea, the landscape is still of arable fields surrounded by sea walls, and it has a way to go to match Tiengemeten. Despite this, the birding provided some anticipation. Thousands of Brent Geese and Lapwings fed in the fields. Hen Harrier, Marsh Harrier, Merlin and Peregrine hunted around the sea walls or over the areas of un-harvested crops retained to provide food for farmland birds. A single Rough-legged Buzzard and a Spoonbill provided the highlights for the day.

Spoon-fed

Feeding Spoonbill pictures taken by John Bottomley at Titchwell. 

The Wadden Sea islands are remarkable for both migrant and breeding birds. Texel, at the southern end if the chain, is perhaps the best known to birders and has high levels of conservation management involving terns, waders, plovers and Spoonbill.

One key fact is that the island has virtually no mammalian predators, just a few Stoats. This was clear at our first stop; a Sandwich Tern colony of some 1200 pairs, on easily accessible spits and islands but full of chicks. The next stop was one of two Spoonbill colonies on the island, one amongst scrub, the other in saltmarsh, but both on the ground.

Spoonbills have been increasing in the Netherlands since the 1980s. There was an expansion into the Wadden Islands after the colonies at Oostvaardersplassen moved when the site was dried out for some years. The two colonies appear to feed principally on different food. The 'scrub' colony feeds on sticklebacks, with birds foraging principally on the Dutch mainland many miles away. The saltmarsh birds feed on prawns in the Waddensea. The Dutch have developed specialised sluices to allow spring-running Three-spined Sticklebacks to enter freshwater from the sea. This forms a key early food for Spoonbills, as discussed in a previous blog. Prawns increase in size and abundant later in the season and thus the saltmarsh colony breeds later.

So what do we need to get Spoonbills established as a breeding bird? A large wetland nesting site, secure from predation and disturbance, and large food-rich shallow wetlands. Birds may travel many miles between these sites.

Wandering on through dunes we saw numerous Bluethroats (60 pairs on Texel), Bittern (5 boomers in dune pools), abundant Marsh Helleborine and Fen Orchid of the subspecies ovata, with its more oval, hooded and erect leaves. Kentish Plover previously nested here but are now declining in The Netherlands, with the population down to c200 pairs, mainly in the delta region. The habitat looked good and was extensive but human disturbance is a problem.

A newly created scrape held many Little, Common and Arctic Terns, as well as 100+ pairs of Avocets. With increasing pressure on beaches, this is exactly the sort of conservation action that is required for our terns. Nearby we looked over a saltmarsh wader roost, holding 10,000+ each of Curlew, Oystercatcher and Knot, and 20,000+ Bar-tailed Godwits.

What the Heck?

 

A bull Heck Cattle, Great White Egret and a forest of Red Deer stags - it is summer, the bushes are dead.

Oostvaardersplassen in The Netherlands is often held up as a fine example of large, natural dynamics management; but is it all it's cracked up to be?

A few days in The Netherlands exchanging views with Dutch counterparts was a chance to recharge ecological batteries and become inspired again. Speaking with Dutch ecologists the air was thick with bird talk, of detailed bird ecology. Of Purple Herons, Spoonbills, Baillons Crakes, White-tailed Eagles, Eagle Owls and more. Fantastic. The key topics of discussion centred around the strategic management of freshwater and coastal habitats, with an emphasis on potential colonists for the UK.

So, back to the Oostvaardersplassen. The Dutch Ecological Networks Plan aims to create 160,000 ha of ecological networks throughout The Netherlands. The Oostvaardersplassen is part of this network and extends to 60 sq km. The aim is to have a ‘natural’ system controlled by grazing and fluctuating water levels. The wetlands (around half the area) support large numbers of key species, including the largest colony of Great White Egrets in The Netherlands. The drier, peripheral land is grazed by huge herds of Koniks, Red Deer and Heck cattle. We saw several hundred of the 1,000 or so Koniks in one herd. It is hard to come to any other conclusion than that these areas are over-grazed; there is remarkably little diversity other than large herbivores, Greylag Geese, Red Foxes and Ravens. There is so little food in these areas that Marsh Harriers have to forage up to 8 km from the nest to find adequate food.

However, for wetlands, there are some key messages to be taken from here: firstly, big is critical for colonising populations, and secondly, dynamic water management is essential to maintain populations of wet reed species. We need to take this on board in the UK.

We saw White-tailed Eagles with newly fledged young, the colony of Great White Egrets, Savi’s Warblers, Bluethroats, Bearded Tits, Spoonbills, White Storks, Montagu’s Harrier and Goshawk, but more of these later...

White-tailed Eagle and nest (nice turbines!), Koniks, view over the Oostvaardersplassen.