The declining numbers of Brant geese in the Netherlands is caused by the effects of climate change on the lemming population in Northern Siberia. At least, that is what Alterra researcher Bart Ebbinge suspects. For some fifteen years now, Alterra researchers, being part of Wageningen UR, together with Russian colleagues, have been studying the relationship between geese, lemmings and predator animals such as the snow owl, the Arctic fox and the pomarine skua. Ebbinge's Russian counterpart, Prof. Yuri Mazurov of the Heritage Institute in Moscow, presented the results of a study of the ecosystem of the Taymyr Peninsula at a mini-symposium Wednesday, 24 January 2007.
According to Mazurov, the Great Arctic Reserve wilderness area, of which the Taimyr Peninsula is a part , is as large as the Netherlands, with pristine nature that has hardly been touched by the human hand. The report is the product of an international research programme on the consequences of climate change for the area, and possibilities for eco-tourism. Like a similar report published last year relating to the year 2004, this report on 2005 contains all kinds of information about fox territories, bird counts, lemmings, weasels, nests and so forth.
The series of reports is the result of a long-standing collaboration between Dutch and Russian researchers. Since 1990, researchers from Alterra have travelled to Taimyr in Northern Siberia for ten summers now, following the Brant geese as they make their way from the Netherlands, via the Baltic Sea and North Russia, to find a nesting place there. Over those fifteen years, the Dutch and Russian researchers who each year have studied the geese and other migrating birds have developed a fairly complete picture of how the area's ecology is structured. Together with Russian and Dutch colleagues, Alterra's researchers have been working on a new research project, since 2004, to map the wilderness of the Taimyr Peninsula.
At a mini-symposium held to mark the second report about Taimyr, Prof. Frank Berendse, scientific manager of the Ecosystems Centre of the Wageningen UR Environmental Sciences Group, emphasised the vital importance of the Arctic research. 'The biodiversity of the world depends largely on the Arctic areas,' he said.
A nice example of that dependence is the way in which the lemming population in Taimyr affects the Brant goose population. Expedition leader and goose expert Bart Ebbinge of Alterra demonstrated this relationship during the symposium. If there are a lot of lemmings in Taimyr, the Netherlands can expect a large number of young Brant geese. That is because the geese have a high breeding success in good lemming years, since predators then do not scavenge the eggs and hunt the goslings. The researchers are therefore also following predators, such as the snow owl, the snow fox, various gull species and the very aggressive pomarine skua, a large seabird that breeds only in peak lemming years.
Brant geese population numbers have again been on the decline in past years, says Ebbinge. In 1972, when the Danes stopped hunting the geese, numbers of the species grew enormously. But the population once more has shrunk by some thirty percent in recent years. Ebbinge suspects that climate change has played a role in this. In the past decade there have been no good lemming years, with 2005 being the only exception to that rule. In Taimyr, lemmings breed especially vigorously during the nine-month-long winter under a protective blanket of snow, which shields them from the cold and from predators. However, if short periods of thaw set in, the blanket of snow turns to ice, which is fatal for the lemmings.
The researchers operate under harsh conditions in Taimyr. This was especially true in the early years, says Ebbinge, when they slept in tents. Nowadays a small barracks has been put up - including a sauna - and the researchers have laptops and other devices with them that make data collection - and particularly communications - much easier. Thus in the summer of 2005 the researchers were able to report from Taimyr to the Dutch Ministry of Agriculture (LNV) that large numbers of geese could be expected that winter, Ebbinge says, and extra money needed to be reserved to compensate Dutch farmers for the damage they could expect to their grasslands.
For more information about the research and the availabilty of the book contact Bart Ebbinge, + 31 317-478729.