New Models Reveal the Distribution of Waders in Iceland

If you want to increase your chances of spotting your favourite waders, a new study could greatly help. Researchers have developed a suite of species distribution models that reveal how climatic and environmental factors shape where different waders are most likely to occur. However, these models are more than just scientific or birdwatching maps, they provide vital tools for conservation. By identifying areas that are suitable for multiple species, the study highlights hotspots where conservation actions could be most effective. This approach allows managers and policymakers to prioritise landscapes that deliver the greatest benefits for Iceland’s rich birdlife

The research was carried out in collaboration between the University of Iceland’s research centre in South Iceland; the Icelandic Institute of Natural History; the Northeast Iceland Nature Research Centre; the Westfjords Nature Research Centre, and the East Iceland Nature Research Centre. The study, led by Verónica Méndez and Tómas Gunnarsson, was recently published in Wildlife Biology, a journal of the Nordic Society Oikos.

“Our aim was to understand how wader breeding distributions are influenced by environmental and climatic gradients,” explains Verónica, research specialist at the South Iceland Research centre, who has also studied the oystercatcher in recent years. “By combining detailed occurrence data with variables such as elevation, vegetation cover, slope, proximity to water, and precipitation, we were able to build probability maps for the entire country showing where different species are most likely to occur. Importantly, these maps also highlight areas where several species overlap, making them especially valuable for conservation planning. Because the likelihood of finding waders is closely linked to their density, the maps also provide a reliable picture of where waders are most abundant”.

The resolution of the models is 300 x 300 metres, and their predictive value is generally good, according to Tómas Grétar Gunnarsson, director of the research centre. Waders are among the most common birds in Iceland during the summer. They are susceptible to habitat changes, and their behaviour provides clear indicators of various developments, such as climate change, pollution, and land use. While most people agree on waders' beauty and ecological importance, not everyone realises they are key predators of small animal populations in coastal and terrestrial environments, such as insects, worms, and crustaceans. At the same time, they are an essential food source for other animals, including falcons, merlins, skuas, foxes, and gulls.

Waders are not evenly distributed

Several fascinating points are highlighted in this new article. Results show that species distributions are far from uniform. Generally, the highest numbers and the most remarkable species diversity are found in vegetated lowlands and low moorlands, areas that also experience the most significant changes in land use. Species with southerly ranges, such as the redshank, black-tailed godwit, and oystercatcher, are largely confined to lowland areas, whereas species with sub-Arctic ranges, such as the golden plover, whimbrel, and dunlin, extend into the highlands, but still show a strong preference for lowland areas and vegetated land on the edges of the highlands. Species with more northerly ranges, such as the ringed plover and sanderling, are found equally in highland and lowland areas.

Tómas notes that habitats that appear similar, such as moorland in different locations, can vary in their value to waders depending on specific conditions in each area. “This highlights the importance of identifying key areas and landscape units and developing conservation plans that cover larger regions and parts of the country—if the goal is to preserve healthy wader populations for the future. Other demographic studies of waders also support such conclusions.”

Caution advised when using models blindly

The authors caution, however, against using the models to make fine-scale predictions at the level of very small sites. While the maps are reliable at broader spatial scales, they cannot substitute for field surveys when assessing the ecological value of specific plots of land. 

A tool for the future

By combining species distributions across environmental and climatic gradients, this new research provides a blueprint for future conservation. It shows where efforts can be concentrated to protect the greatest number of species and the habitats they rely on.

“These models are not just about mapping where birds are today,” says Verónica. “They give us a framework to anticipate future changes and to ensure that Iceland’s waders remain a defining feature of the landscape for generations to come.”

The article is available in open access