By Kandy Curran, Roebuck Bay Working Group

Professor Theunis Piersma’s footprint on the mudflats of Roebuck Bay and Eighty Mile Beach will go down in scientific history, for 20 years of continuous research of the wetland’s remarkable migratory shorebirds and rich invertebrate life. 

Recognising the critical importance of the benthic fauna from his base at the NIOZ Royal Netherlands Institute of Sea Research, Professor Piersma made the long journey to the remote town of Broome in 1996, to see the Ramsar listed wetlands for the first time. 

Speaking at the Science on the Broome Coast series on October 6, 2016, Professor Piersma presented findings from this research, including disturbing news of the alarming population decline in migratory shorebirds using the East-Asian Australasian Flyway.

Pebble crab (family Leucosiidea) © Kandy Curran

As Professor Piersma explained, ‘a benthic invertebrate dataset is being amassed from the results of monthly mud sampling Roebuck Bay since 1996 (in collaboration with Broome Bird Observatory and Parks and Wildlife Yawuru joint management team), and from major benthic mapping expeditions in 1997, 2002, 2006 and 2016, where volunteers and scientists sieved mud from 2,000 locations, turning up a staggering 50,000 invertebrates.

Incredibly, colourful topshells, tiny mudwhelks and snails can reach an abundance of 3,000 per square metre in Roebuck Bay’s intertidal mudflats. Bivalves are plentiful too, with more than 30 different species. Surprisingly though, the most abundant and diverse animals are worms. Some of these remarkable benthic invertebrates are superfoods for migratory shorebirds, replenishing fat stores for their annual life cycle along the flyway.

 

The benthic expedition underway on Roebuck Bay’s remarkable intertidal mudflats. © Kandy Curran

 

Australia however, is only one of nine flyways of the world under growing pressure. In 2006, Professor Piersma procured international funding to establish the non-profit Global Flyway Network to better understand and help conserve migratory shorebirds in a rapidly changing world. Through the Global Flyway Network, Broome ornithologists are employed to conduct shorebird research on Roebuck Bay, Eighty Mile Beach and at the migratory shorebird’s staging grounds on China’s Yellow Sea.

Sadly, these studies are showing a significant decline in populations of migratory knots and godwits. Professor Piersma says, ‘My hypothesis from a large data set, is that habitat loss and environmental degradation of the Yellow Sea mudflats is the key factor in this downward spiral.’

 A world leader in wetland and waterbird ecology, with a long list of prestigious scientific awards, publications and books, Professor Piersma’s  take home message is, ‘Don’t take Roebuck Bay for granted, since this remarkable embayment has the richest intertidal mudflats in the world’.

The Science on the Broome Coast series is hosted by the Roebuck Bay Working Group and Yawuru Land and Sea Unit in Broome, and sponsored by Inspiring Australia, Rangelands NRM through the Federal Government Landcare program, State NRM through Royalties for Regions, Western Australian Marine Science Institution, Department of Parks and Wildlife and University of Notre Dame Broome.

Read more about the Roebuck Bay benthic survey here.

Grant Pearson, Randal Tabrizian, Kandy Curran, Professor Theunis Piersma © Kandy Curran

Kimberley Marine Research Program