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.