Shorebirds are birds commonly found along sandy or rocky shorelines, mudflats, and shallow waters all around the globe. But a study co-authored by Czech scientist Vojtěch Kubelka shows that these birds are increasingly threatened with extinction. The research, recently published in the prestigious US magazine Science, reveals a link between nest predation and climate change on a global scale, but especially in the Arctic.
“That’s true. Shorebirds are all over the world but in the Czech Republic we have only nine to eleven species breeding. I have been fascinated by shorebirds for many years and I have three reasons for that. First of all, they can be nearly everywhere, in any environment from deserts to high mountains and from rain forests to the Arctic.
“They have really diverse mating strategies. They can even reverse the sex roles, with females fighting each other to attract males, and males taking care of eggs and chicks.
“They also migrate over huge distances. They can flay ten thousands of kilometres without stopping from Alaska to New Zealand, so they are real record-holders in the avian kingdom.”
So when did you actually start studying shore-birds and what exactly was the focus of your study?
“I started studying shorebirds 12 years ago here in the Czech Republic. We set up a new working group for shorebirds in the Czech Republic. We have done many small-scale studies and conservation projects.
“This particular study started in 2015 and focused on the nest predation - that means how often eggs are taken away from the nest by predators. I started by studying nest predation data in already published literature.”
One of the main conclusions of your study is that climate change can impact relations between different species on a global scale. How did you arrive to that conclusion?
“According to our study, interactions between a predators and prey are really disrupted by the climate change. This is an indirect link that climate change can change the abundance of prey, in this case lemmings, small rodents which are the base of the food-web in the Arctic.
“Due to global warming and the repeated melting and freezing of snow cover during the winter, these creatures are struggling to get to the food under the snow. As a result, they disappeared at many places in the Arctic around the year 2000. And without the lemmings, the Arctic predators are predating on alternative prey, in our case shorebirds nests.
“So this is the indirect link, but there is also a direct correlation. We recorded the highest nest predation rates on sites, where global warming was most pronounced.”
Which species are we talking about? Which species in particular prey on shorebirds’ nests?
“In the Arctic, it is mostly the Arctic fox, raven, corvid birds and gulls a well as weasels. In temperate regions, for instance in the Czech Republic, the red fox is the biggest predators of shorebirds’ nests, and also hedgehogs and corvid birds. Going down to the tropics there are lizards, snakes and even crabs.”
How serious is the problem? Does it mean that if the climate warming continues, shorebirds will be threatened with extinction?
“That is true. Shorebirds are threatened by several other factors as well. We have proved that they have really low reproduction rates, which means that there are less young birds.
“At the same time, their habitat is shrinking. The Arctic cannot be moved anywhere else, it is the end of the world. That means the birds are likely to struggle a lot.
“They also encounter problems along the way, on their stop-over sites, especially in the Yellow Sea in China and Korea. The intertidal mudflats, which they use to refuel during migration, are disappearing really quickly. Therefore it is not surprising that shorebird populations are declining worldwide.”
Can anything be done to prevent the situation?
“From the global perspective we can do more by preserving the intertidal mudflats to increase their adult survival rate. Shorebirds can live for quite a long time and if they live longer than they have more opportunities to reproduce.”
Was there anything in particular that you found surprising while conducting the study?
“We tested the predicted and assumed latitudinal gradient in nest predation which was assumed to be higher in the tropics where there is higher variability of predators and we really saw this pattern but only on the historic data set, before the year 2000.
“And after that year 2000 we have been really surprised by the rocket increase of nest predation in the temperate and especially the Arctic region. We expected there could be some increase, but not so rapid and not so tightly linked to the lemming disappearance.”
Does that mean that the climate changes are more pronounced in the Arctic than elsewhere in the world?
“It’s tied to the fact that on the southern hemisphere the climate change is not so pronounced.”
Does your study what could be done in the future in terms of environmental protection?
“In the Arctic, it is really difficult to stop the climate change and of course it is debatable to what extent people are responsible for the climate change. Through the history of the planet, several rapid changes have already occurred, although not as rapid as this one.
“In the Arctic, we can help protecting particular nests, but what is more important right now is to stop the disappearance of the vast intertidal mudflats along the shores, especially in East Asia.”
The article, which has just been published in the Science magazine, was part of your dissertation, which you defended only a few weeks ago. What will you do next? Are you planning to continue in the same field?
“Of course nest predation is just one part of the shorebirds’ cycle, and some of my colleagues laugh that I could use all the collected data for the rest of my career.
“But of course I like to do new things. So we are planning to extend our story, since there are several possible follow-ups, but I am also working, together with Professor Tamás Székely from Debrecen, on a new project, focused on the sex roles of shorebirds all around the world.”
You published your story while still a student. How important to have your study published in such a prestigious magazine for your future career?
“It’s very important and I am very glad that we made this achievement. Of course it is not just my own, since we have a bigger team. I published the article just before finishing my studies, so it opened many possibilities for my future career.
“In many situations, we have simply been lucky, because although you work hard, you must also have luck. So we are really happy and it is really important for us.”