Going, going, Rudong

After a weeks ‘lock in’ at Chongming Dongtan, the design work to create a series of lagoons, reedbed and saltmarsh was nearing completion. The final task was to present the plan to an assorted group of Shanghai officials, reserve directors and academics from the local Fudan University. Two hours ecological quizzing by the professors was somewhat challenging but seemed to go okay and then off to lunch with our very hospitable hosts. The custom appeared to be for each person considered to be a host to individually drink a toast to each guest with rice wine. There were a lot of hosts. Refills and toasters kept coming. Then the food, a lovely mix of local dishes; fish, shrimp, shellfish, succulent pork, duck and ‘poison fish’ soup. I like this sort of trip.

With the job done, a bit of free time was in order and we were soon off on the 2-hour trip up the coast to the fishing port of Rudong. But not before we had a bit of feedback on a colour-ringed Black-faced Spoonbill I had photographed on the reserve a couple of days before. It was a second year bird, ringed as a nestling in Korea in July 2012. It wintered at Mai Po reserve in Hong Kong until May 2013 before turning up at Chongming Dongtan. On arrival at Rudong, we were pointed by local birders towards an area of coastal scrub good for migrants. An old man was selling incense from a small brick building on the edge of the area. We saw a few Siberian Thrushes, Pale-legged Warbler, Asian Brown and Yellow-rumped Flycatchers, Richard’s and Red-throated Pipits headed south calling.

Then off to the mudflats and a walk out amongst the giant wind turbines, shellfish gatherers and assorted vehicles. Lots of Great Knot, sandplovers, stints, Broad-billed and Marsh Sandpipers, a few Nordmann’s Greenshank and then a small feeding flock of the target bird; Spoon-billed Sandpiper. Little is known about the feeding requirements of Spoonies on migration but Rudong is clearly an important site. Up to 50 birds had been counted here in the last week and every one we saw was in wing moult. By now the local press were aware of our presence and were hot-footing it across the mud. Close behind them were representatives from the local authority with an invitation to lunch; an opportunity to press home some points on shorebird conservation. A major area of the Rudong mudflats is destined to become a port in the near future. Presumably the area amongst the turbines will stay, but still raked daily by hundreds of fishermen, pulling out ragworms and shellfish. The high tide approached, the sea rushed in and the waders poured over the sea wall to roost on recently reclaimed land; soon to be built on. As we returned for lunch, we passed the area of scrub. Half had been freshly bulldozed, as had the building the old man had been selling incense from. Just a pile a bricks remained. Such is the speed of development here.

Pics: above - Spoony, Black-faced Spoonbill and Rudong mudflats.
Below - Great Knot, Marsh Sand and 2 hours trading left.

Knot work

Work trips are not all there are cracked up to be. While Dark-sided Flycatchers call from outside and Eastern Crowned Warblers crash into the window trying to draw attention, we have to sit all day in a room discussing the finer details of Reed Parrotbill diet and Saunders’ Gull nesting requirements as we try to design a 2,500 ha nature reserve. How can we provide more food for Black-faced Spoonbill?

Yesterday however, we did get out early. Wading barefoot through the mudflats of Chongming Dongtan nature reserve, we talked to bird ringers catching waders and local fishermen catching shellfish. The ringers were catching and colour marking waders; with the aim of adding to the knowledge of how waders use the East Asian-Australasian flyway. The catch was mainly Broad-billed Sandpipers, Long-toed and Red-necked Stints. The birds are caught by specialised bird catchers using clap nets with decoys. The fishermen were mainly sifting the bivalve Corbicula out of the mud to try and earn a crust; this beast also being a major food source of the Great Knot. But the introduced Spartina a vigorous grass growing to 2m tall, threatens both the fishermen’s livelihood and the Great Knot. Fishing for shellfish in the reserve seems a bad idea but the shellfish company also sprays out the Spartina that is marching across the mudflats at an alarming rate. The mudflats held Greater and Lesser Sandplover and Grey-tailed Tattlers. All day long birds moved south, calling flocks of Wood Sandpipers, Marsh Sandpipers, Terek Sandpipers, Far Eastern Curlews, Great Knot, and Whimbrel, along with hundreds of White-winged Black Terns, Swallows and Yellow Wagtails. It was okay I suppose.

“What does the ecologist think” stops me daydreaming about yesterday and brings the mind back inside to the theory. One of the reserve’s key species is the Marsh Grassbird, a skulking species with a distribution split into a number of isolated sub-populations across China, Japan and Korea. At Chongming, it is one of the few species found in the Spartina marshes. Can we remove the invasive Spartina without losing Grassbirds? Elsewhere it is found in more varied marshy grasslands including overgrown rice paddies. Breeding birds seem to prefer dense, mid-height reeds and grasses in shallow water for nesting, with some taller plants for singing posts. Now, where shall we create the islands for breeding Saunders’ Gull? Can we grow a sacrificial rice crop to lure the Hooded Cranes off the adjacent farmland? Outside it starts to get dark, the flycatcher rattles off to roost and Night Herons fly past the window. Kwak.

Chongming Dongtan

Touchdown in Shanghai and just a few hours in China is enough to grasp the enormity of the environmental problems in this country. The rate of concrete pouring and coastal land reclamation is astounding. We are based at Chongming Dongtan Nature Reserve at the mouth of the Yangtze River for two weeks. This is a major staging post for waders, with good feeding mud flats being lost at an alarming rate. There can be little doubt that coastal wetlands along the East Asian-Australasian flyway are facing an ecological crisis.

We are in China to work on the design of a major wetland creation project. There is a plan is to build a huge new 25 km seawall, enclosing 2,500 ha of Spartina dominated saltmarsh around the nature reserve. The wall is being built to enable the introduced Spartina that has spread across the mudflats to be removed and the opportunity exists to work with the excellent reserve staff here to create the best possible habitat for key species after removal.
Chongming Dongtan is located at the eastern part of the Chongming Island, which is a low lying alluvial island. Due to the sedimentation of mud and sand from the Yangtze River, Chongming Dongtan consists of large areas of fresh water/salty water marshes, tidal creeks and inter-tidal mudflat, where there are farmland, fish and crab ponds and reed beds. It is an important staging and wintering site for migratory birds. Key species here are Hooded Cranes, Reed Parrotbill, Marsh Grassbird, Black-faced Spoonbill, Saunders Gull and the waders of the East Asian-Australasian flyway. The highlights of a quick look around on day one were a large flock of Reed Parrotbills and evening meal of shrimp, duck, mushroom and noodle. The waitress gave me a dirty look while others laughed; apparently I had greeted her with “hello mother”.

Forest Monkeys reveal secrets

The Dutch name for Little Bittern is Woudaap, which in direct translation means Forest Monkey.  Last weeks work involved a great deal of nimble movement through reedbed ‘forests’, culminating in the Somerset Forest Monkeys revealing some of their secrets.

We started with a good deal of thrashing about in the reedbeds at Minsmere.  Thinking about climate change, the impact of too many Red Deer, and natural succession in an ageing reedbed.  How are we going to manage this site over the next 25 years?  Nothing beats getting into the habitat and experiencing it close-up to understand what needs to be done.

Then on to Snape, where new wetlands are being created.  A bit of electro-fishing to understand how the fish populations are developing, then a look at the area currently being created to add a few tweaks to the design; imagining yourself in a metre of water surrounded by reeds and thinking what features would attract a feeding Bittern or a Great White Egret.

Then down to Ham Wall, where after a summer of meticulous recording by a superb group of volunteers and local birders, we soon homed in on the Little Bittern nesting and feeding sites.  Water depths, edge profiles, reed characteristics were all recorded and some electro-fishing revealed the secrets of the Forest Monkeys favoured feeding areas.  Such details will be invaluable in creating similar habitat elsewhere.

One interesting fish caught in some numbers at Ham Wall was the Moderlieshen or Sunbleak Leucaspius delineatus, a non-native species that has a highly developed life history strategy. The majority of cyprinid fish species take 2-4 years to become sexually mature and spawn just once a year. The females scatter many thousands of eggs over aquatic macrophytes or gravel,and these are then left unguarded and vulnerable to predation.  Unusually for cyprinids, the Moderlieshen become sexually mature at one year old and are batch spawners, with females laying several batches of eggs, between April and July, which are guarded by the males until they hatch. They were first recorded in the Somerset Levels around 1990, their origin unknown but likely to have arrived via some fish stocking by anglers.

Photos above - Moderlieshen, Little Bittern nest.

I knee-d a Purple Emperor

The first Purple Emperor of the day landed on my shorts and wandered around my knee for a few minutes, no doubt remarking on my sweaty qualities.  Frustratingly, no amount of contortion could get the beast into focus through the camera lens before it soared off over the woodland canopy.  So began my walk around Broxbourne Woods this weekend.  After the first Emperor of the day they became decidedly scarce for a while and it seemed I would not get a decent photo, unlike Silver-washed Fritillaries, which were everywhere.  I have walked these woods since the 1970s and never have they been so numerous. They were distinctly hard to find in the 1970s-1990s but now every sunny glade seems to have a few. A remarkable change in status.  Likewise the Purple Emperor.  In the early days, every White Admiral was scrutinised in the hope of finding the Emperor.  Now almost full circle, I saw more Emperors than Admirals on my two hour walk.

At Danemead, a Herts and Middlesex Wildlife Trust nature reserve within the woods, Broad-leaved Helleborines were just coming into flower and the exit holes of Goat Moths were still evident in the small group of old trees that they have inhabited for decades.  Back in the depth of the planted conifers, a family party of Firecrests mingled with a large mixed flock of tits and 9 Crossbills chipped away from the top of a Larch.  On the final stretch back to the car park, Purple Emperors at last began to perform; a couple zooming around large sallows, a couple more taking moisture from the damp path and a final individual sucking away at a gate post.

Photos: my feet, Silver-washed, White Admiral and PE.

 

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.

Lac de Grand-lieu

The Lac de Grand-lieu has been the origin of many of the colour-ringed Great White Egrets seen in the UK; a power-house for herons and another launching pad for UK colonisation.  A day on a boat with the warden Sebastien Reeber brought home what an amazing wetland this is.   The Lac de Grand-lieu has open water (the lake), reed, marsh extensive willow scrub, wet woodland and surrounding wet grassland.   The water is around 0.8-1.5 m deep in summer but rises by 2 m in winter to cover an amazing 6,000 ha. The levels fluctuate annually to maintain a huge dynamic wetland.

The summer extent of the lake is around 2,000 ha and of this 1,000 ha is covered in water lilies.  It took half an hour or so to pass through the lily zone, mobbed all the time by Whiskered Terns.  Sebastien listed the breeding birds: 2,000 pairs of Whiskered Tern, 1,000 pairs of Cattle Egret, 160 pairs of Spoonbill, 300 pairs of Little Egret, 160 pairs of Purple Heron, 250 pairs of Night Herons, 700 pairs of Grey Heron…….  In winter, there are 13,000 Shoveler, 5,000 Pochard...  The Great White Egrets have been established as a breeding bird since 1994 and have increased to a current total of 160 pairs over the last 20 years.

The wet grassland beyond the lake will typically be submerged by 1m or more of water during the winter before the levels drop in April/May.  The breeding birds include Black Tern, Black-necked Grebe and occasional Ruff amongst the more familiar waders.  The ‘yellow’ wagtails on site are an intergrade between flava and iberiae with a corresponding range of head patterns.  An endangered plant now restricted to just a handful of sites in the UK, Starfruit was abundant along the tracks, along with Lesser Water-plantain.

The wetland is however, far from being in a ‘natural’ state.  Invasive non-native species are a major problem, with some of the most obvious being Red Swamp Crayfish, Sacred Ibis, Black Swan, Coypu and Muskrat.  We don’t want any of these in the UK!   And yes, there are plenty of Ruddy Ducks.  The Sacred Ibis are being controlled.  Formerly 800 pairs, they are now reduced to around 300.  The Ibis are a major predator of the eggs of birds on the wet grassland but perhaps more of this later.

Red Swamp Crayfish is now abundant in the wetland – abundant to the tune of 2 tonnes of crayfish per hectare. Perhaps their most obvious effect is the devastating loss of submerged aquatic weeds.  RSC have previously spread throughout the Camargue, where they have been well studied since they were first found in the 1990s.  The RSC have a varied diet (insects, fish, amphibians, plants and seeds) essentially made up (80%) of organic matter and detritus.  Introduction of crayfish into ponds showed that after 10 weeks a density of 3 RSC m² leads to an 80% decrease in the biomass of macrophytes and a 33% decrease in the diversity of macro-invertebrates.  On the plus side, they now form the major prey item for some wetland birds; 67% of the diet of Bitterns and up to 80% of the diet of Glossy Ibis, Spoonbill and Cattle Egret.  The Red Swamp Crayfish create a direct link in the food web between organic detritus and the top predators, providing the latter with a large invertebrate prey (primary consumer) in high numbers, increasing the overall amount of food available to them.   Even I can’t eat enough crayfish to get us out of this mess.

Above - lilies, Whiskered Tern, and nest.  Below: not-so-sacred Ibis, Starfruit, Flava/iberiae wag.