House sparrows in northern Norway can help us save other endangered animals

(Press-News.org) Researchers are trying to understand why some wild species do better than others over time, as the environment changes.

Researcher Kenneth Aase's research focuses on a new mathematical approach that could shed light on this question, which in turn could move us closer to understanding the loss of biological diversity. Aase is a statistician and a PhD research fellow at the Norwegian University of Science and Technology (NTNU's) Department of Mathematical Sciences. He is associated with the GPWILD project, funded by a European Research Council Consolidator Grant. The project involves using biology and mathematics to understand more about a species' adaptive evolutionary potential, and relies on genetic and body data from tens of thousands of house sparrows who live in the northern Norwegian district of Helgeland.

Why house sparrows? House sparrows turn out to be the perfect critter for research like Aase’s.

"Because our island populations are small and delimited, they are exceptionally well suited for research. Biologists can record and follow almost all individual sparrows from birth until they die,” Aase said.

NTNU researchers at the Department of Biology and the Gjærevoll Centre have been studying these house sparrows for more than 30 years, and have an enormous database of information, he said.

"They can investigate what affects their survival, and how many young they have. We have been collecting such data for over 30 years, and have produced long-term datasets that are both unusual and completely invaluable. They help us understand the consequences of changes in the environment, as well as genetic and ecological development over many generations,” he said.

And what’s more, “what we learn is transferable to many other species,” he said. 

Genomic prediction as a tool Aase’s work focuses on a technique called genomic prediction, or GP.

This is a statistical method for finding out how an individual's genes affect a trait in an individual or a human being. The trait can be anything that can be measured, such as height, illness, or body weight. The method can be used to predict how much yield a grain plant can yield, or whether a person is genetically predisposed to certain diseases, Aase said.

"The method can also tell us whether the genes of a given house sparrow will give it a higher or lower body weight. This is important for the sparrow's ability to survive. GP is widely used in plant and animal breeding, but so far it has not been used much in research on populations of wild animals and plants,” he said.

As the researchers have gained more and more access to genetic material from wild populations, Aase and his colleagues, led by Professor Stefanie Muff, will investigate how useful the method can be in ecology, evolution and conservation biology.

From a training group to an individual All of this genetic information enables the researchers to use hundreds to millions of genetic markers spread across the genetic material, and link them to measurements of the trait from a “training group”.

The statistical model works even if the trait they’re interested in hasn’t been measured in the given individual – it is enough to have measured it in the training group.

"As long as we have information from the same genetic markers in both the training group and the individual, we can calculate how the genes affect the trait. The accuracy depends in part on how many individuals are in the training group, the number of genetic markers, and the heritability of the trait,” Aase said.

Tested in different populations The researchers wanted to know how accurate their statistical model would be if their training group consists of sparrows from a different population than the individuals they were interested in.

“This is important in order to be able to investigate crucial natural processes in new and more efficient ways. For example, we can save a lot of fieldwork, because the researchers do not need to obtain measurements of traits from each individual population they are interested in,” Aase said.

Here’s where the house sparrow data from Helgeland was perfect for the researchers to test their model on.

"In the new study, we used measurements of body traits from wild house sparrow populations from islands along the Helgeland coast. Because the islands are more or less clearly separated, we could answer the research question by making predictions across different islands and archipelagos,” Aase said.

Aase and his colleagues found that making predictions with a training group from one sparrow population for other, different sparrow populations in the islands didn’t work as well as when they made predictions with a training group from the exact same sparrow population.

"We found that predicting across different populations works less well than within populations. This was expected, based on previous studies in breeding and medical research. However, we were the first to demonstrate this in wild populations. We also provided new insights that can be useful for improving GP across populations,” he said.

Wild populations challenging The technique of using GP was developed for use with domestic animals, where researchers have access to all the genetic information they need. That’s not always the case with wild populations, Aase said.

“For us statisticians, perhaps the biggest challenge is that field datasets are often incomplete. We do not always get genetic data or measurements of all individuals. In addition, we usually do not have data from controlled trials, for example because environmental conditions change over time and space,” he said.

"Studies of wild animals are often exploratory rather than confirmatory. There are few such thorough and long-term studies of wild populations in the wild, but the house sparrow data made this new study possible,” he added.

That’s where the Helgeland house sparrow data offer clear advantages, because it is almost complete, he said.

"As a statistician, I am fortunate to have the data served on a silver platter by the biologists I collaborate with at the Gjærevoll Centre and  the Department of Biology at NTNU. They have been working on collecting this unique dataset for more than three decades. So there is a lot of field and laboratory work involved before I get to play with the end result,” Aase said.

"In addition to data from the house sparrow populations, I also use computer simulations where you can test model assumptions. My everyday life is spent programming statistical analyses. For the most challenging computations, I use NTNU’s supercomputer IDUN,” he said.

Facing the “sixth mass extinction” Natural resource managers and conservation biologists need to know how changes in the environment, either from a warming planet or from loss of habitat – or both – will affect wild populations.

That’s where using GP as a tool can make a difference, Aase said.

"Climate change and increased land use mean that many populations of wild animals and plants are exposed to increased external pressure and faster environmental changes. Understanding both the genetic and ecological consequences of this is necessary for nature managers and conservation biologists to be able to prioritize measures, such as which populations need protection and how,” he said.

"GPs can tell us about how viable individuals are under given environmental conditions. Thus, it can be used to reintroduce or strengthen populations. This knowledge also helps to increase our basic understanding of natural processes, and how evolution actually plays out in nature,” he added.

In this way, “studies of house sparrows in populations along the Norwegian coast can help us preserve populations of other species that are threatened with extinction due to the changes we humans make in nature,” he said.

The world is facing a biodiversity crisis, where human activity is causing what is called the “sixth mass extinction”.

“If we want to stop this development through targeted measures, we need both good analytical tools and basic knowledge about how evolution in nature works. I would also argue that there is an intrinsic value in such a basic understanding,” Aase said.

From house sparrows to Svalbard reindeer As he proceeds with his PhD research, Aase will continue to investigate how genomic prediction can be used in wild populations.

“In GPWILD, we're going to put these questions into a broader framework. The project will work with several other animal species, such as Svalbard reindeer, deer from Scotland, arctic foxes, and several bird species,” he said.

But he isn’t quite done with house sparrows just yet,

"Currently, I am working on an applied study where GP is used to investigate how certain genetic processes affect the fitness of the house sparrow,” he said.

Reference:
Kenneth Aase, Hamish A Burnett, Henrik Jensen, Stefanie Muff, How accurate is genomic prediction across wild populations?, Evolution, Volume 79, Issue 12, December 2025, Pages 2612–2628, https://doi.org/10.1093/evolut/qpaf202

Aase's academic article was as an "Editor's Choice" article for December in the academic journal  Evolution.

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