The lesser white-fronted goose and the Arctic fox tell of Arctic change

The situation of the critically endangered lesser white-fronted goose has fluctuated in Finland and the Nordic countries over the past decades. At one time it was thought to have disappeared from our breeding population, but at the last moment the population in the Nordic countries started to increase and grew quite promisingly between 2005 and 2017. In recent years, however, the population has again taken an alarming downward turn due to several consecutive years of poor breeding.

"When the monitoring and conservation work on lesser white-fronted geese started in Finland in the 1980s, not much was known about the species' situation and migration routes. Over the decades, many things have become clearer, but more information is still needed. The lesser white-fronted goose is our only goose that migrates south-east towards Greece and the Caspian Sea for winter. There, it is hunted extensively. In addition, the lesser white-fronted goose needs natural grasslands for its migration and is not well adapted to feeding in cultivated areas. Along migration routes, important habitats for the lesser white-fronted goose have been destroyed, which has affected the population," says Petteri Tolvanen, WWF's Programme Manager for Finnish Nature. He has been monitoring the lesser white-fronted geese since the early 1990s.

Tolvanen is a member of the multidisciplinary advisory group of the Arctic Interactions programme led by the University of Oulu. The group has met on a regularly irregular basis during the programme period. The meetings are used to exchange ideas and experiences and to raise Arctic research issues on various topical themes for discussion.

For the lesser white-fronted goose, the main risks are related to the migration of the species and the feathering in Siberia after an unsuccessful breeding season. In the event of unsuccessful breeding, the geese will migrate from the North to the far east to renew their plumage before their autumn migration. This means that they will have chosen a much longer and more dangerous route than the birds that have successfully nested.

For the lesser white-fronted goose, breeding success is also influenced by fluctuations in the populations of voles and lemmings, which are important for the Arctic fox. When voles and lemmings are abundant in the fells, the lesser white-fronted geese can nest in peace from predators. Arctic foxes and other northern predators are then mainly after rodents. In bad years for voles and lemmings, the lesser white-fronted geese and their nests are also more attractive to predators when predators are short of food.

"Vole and lemming populations have typically fluctuated cyclically, with a peak year every 4-5 years or so. This cycle went haywire in the 1980s and 1990s for an extended period for an unknown reason, possibly due to climatic factors. There were no good rodent years for several decades. 2005 was a good year for lemmings again, fortunately. It also marked the beginning of the recovery of the lesser white-fronted goose population, which had been on the verge of extinction, continuing until 2017. The summer of 2023 is predicted to be a good summer for voles, so let's hope for the best," says Tolvanen.

In nature, many things influence each other, so finding explanatory variables and causal links can be tricky. This requires continuous research and long time series.

Born in Helsinki, Tolvanen is a biologist who has always felt most at home at the outer archipelago and Lappish tundra. With regard to the lesser white-fronted goose and the Arctic fox, Tolvanen is interested in the rarity of the species and the need for conservation. Conserving biodiversity is also a key objective of the WWF.

"Like many other Arctic species, the lesser white-fronted goose and the Arctic fox are acutely threatened by climate change. Species in the tundra and the Arctic are naturally quite scarce and it is these species that are now under great threat. Humans should remember that biodiversity is also the basis of human life and existence. If nature is not doing well, then in the long run, problems will pile up and become problems for all humanity," Tolvanen said.

The WWF is an NGO whose work is based on research and the use of scientific knowledge. Tolvanen has therefore welcomed the existence of large-scale research projects such as the ARCI programme. Multidisciplinary discussions are eye-opening and bring new ideas to the table. It reduces the need to be stuck with one's own ideas and approaches, which means that solutions to problems can be found in unexpected places.

"Researchers are often too narrowly focused on their own research topic, and among like-minded people. Many researchers are also very cautious when presenting their research findings and conclusions. Research data should be better popularised and thus more accessible to policymakers. The ARCI programme is a good tool for this. New knowledge alone is not enough. We also need insights into what can be done and achieved with the information," Tolvanen emphasises.

Photos: AdobeStock, Petteri Tolvanen, Erkki Alasaarela