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These house sparrows can help us save other endangered animals
How much does it matter where a house sparrow is born, or whether it is heavy or light? A researcher has examined what the future might look like for these grey-brown birds.
Researchers are trying to understand why some wild species do better than others over time, as the environment changes.
Researcher Kenneth Aase is working to develop knowledge that can help stop the loss of biodiversity.
Why house sparrows?
“Because our island populations are small and clearly defined, they are exceptionally well suited for research. Biologists can record and follow almost all individual sparrows from birth until they die,” Aase says.
For example, they can investigate what affects their survival and how many offspring they have, he explains.
“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 says.
And what they learn can be transferred to many other species.
What is genomic prediction (GP)?
"It's a statistical method fused to determine how an individual’s genes affect a trait in an individual or a human," says Aase.
The trait can be anything that can be measured, such as height, illness, or body weight.
The method can be used to predict how large a yield a grain plant can produce, or whether a person is genetically predisposed to certain diseases, the researcher explains.
“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 livestock breeding, but so far it has not been used much in research on populations of wild animals and plants,” he says.
As the researchers have gained more and more access to genetic material from wild populations, Aase and his colleagues will investigate how useful the method can be in ecology, evolution, and conservation biology.
Calculating traits for individual animals
"We can use hundreds to millions of genetic markers spread across the genome and link them to measurements of the trait from a group of 'training individuals',” the researcher explains.
The statistical model works even if the trait they’re interested in has not been measured in the specific individual. It's 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 individual’s genes affect the trait," he says.
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.
How well does the method work across 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 investigate crucial processes in nature in new and more efficient ways, the researcher explains.
"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 says.
“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,” he adds.
They found that predicting across different populations works less well than within populations. This was expected, based on previous studies in breeding and medical research, according to Aase.
“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 says.
Challenging to work with wild animals
“There are many challenges in working with wild animals. For us statisticians, perhaps the biggest challenge is that field datasets are often incomplete. We don't always get genetic data or measurements of all individuals," says Aase.
He adds that they usually don't have data from controlled trials, for example because environmental conditions change over time and space.
“Studies of wild animals are therefore 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 explains.
Collaborating with biologists
“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 NTNU's Department of Biology," says Aase.
They have worked on collecting this unique dataset for more than three decades.
In addition to data from the house sparrow populations, he also uses computer simulations where researchers can test assumptions based on models.
What should this knowledge be used for?
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, Aase explans.
"Understanding both the genetic and ecological consequences of this is necessary for nature managers and conservation biologists to be able to prioritise measures, such as which populations need protection and how,” he says.
GP can also tell us how viable individuals are under given environmental conditions. This means it can be used to reintroduce or strengthen populations, the researcher explains.
This knowledge helps to increase our basic understanding of natural processes and how evolution actually plays out in nature.
“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 says.
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, 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 says.
Reference:
Aase et al. How accurate is genomic prediction across wild populations?, Evolution, 2025. DOI: 10.1093/evolut/qpaf202
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