Czech scientist: animal migration threatened by climate change

What kind of impact are these changes having on migratory animals? And are they threatened with extinction? These are just a few of the questions I discussed with Mr. Kubelka, and first I asked him what exactly compels animals to travel such long distances every year:

“There are many migratory species all over the world, usually from the tropics, migrating to the northern temperate and arctic regions and there have been various theories as to why they do so. There are three main advantages for them.

“One is that they encounter here in the north and further north, in the Arctic, a seasonal peak in food supply, which is not available in the same quantities, for example in equatorial regions. So that’s a big advantage.

“There are also fewer parasites when you go further north and a lower predation rate. So these are three main advantages that many migratory species enjoy when they travel north to breed. “

Is the Czech Republic a target country for any of these species?

“It is obvious that many populations are struggling to keep up with these changes and inevitably many of them will lose.”

“We are, actually. We are in the middle, which means that some species from the tropics or the Mediterranean region come here to breed, and on the other hand we have several species that come here just for the winter and then go to the Arctic for reproduce there.

“And of course, we are a stopover for many birds and certain kinds of insects that overwinter in the south, pass through our country and then continue north.”

Your recent study has shown that some of these species no longer benefit from migration to breeding grounds in northern temperate and arctic regions due to environmental changes associated with climate change. What kinds of changes are we talking about?

“In this case, we’ve really covered these three expected benefits and looked at them in more detail. We have some 25 studies describing the disruption of ancient benefits to migratory birds, including food supply, parasites, and predation.

“Unfortunately for migratory animals, it is indeed true that for many populations and species, migration is no longer as beneficial as it used to be.

“Food supply disruptions can explain, for example, a tropical lag, which means that the migrating animal arrives later or is not well synchronized with the peak of abundance in the north.

Vojtěch Kubelka |  Photo: Jan Bendl, Charles University

“Due to global warming, leaf phenology or insect emergence may be faster in the Arctic, and birds that migrate from the tropics are late for these changes. Their chicks may have a lower survival rate, they may starve or not be fed enough to return to the South.

“It’s the disruption of the food supply. Likewise, as a result of higher temperatures, many pests and pathogens enter temperate northern and arctic regions and we have also encountered increasing predation pressures in these areas. “

So what impact do these changes have on certain migratory species? You have already mentioned famine …

“Certainly, if the chicks are more likely to die, then the number of populations will decrease and that could inevitably lead to extinction. Of course, we want to prevent that, but that’s population dynamics.

“Small changes, such as increased predation on nests, result in fewer chicks joining the population and fewer migrating animals.

“Unfortunately, many migratory species already have declining populations and disruptions to past benefits can certainly contribute to this trend.”

How exactly do species react to these changes? Can they develop survival strategies?

“They are definitely trying. Obviously, some species can speed up their arrival in the Arctic and synchronize with climate change, but these are usually species that winter nearby. This means they can anticipate changes and get there on time.

“Unfortunately, this does not apply to species in the equatorial region, because they do not know that the Arctic is already warm. They have been used for millions of years to travel on a schedule that worked very well, but currently they are not.

“So the cash is trying. They can for example avoid places where predation is higher, but if we have a lot of places where these changes are happening, it is more difficult for them.

“What is also very important is to cooperate between whole nations, because migratory animals have no borders.”

“Unfortunately, the current changes are very rapid. There is not much time for ecological adaptation. It is evident that many populations are struggling to keep up with these changes and inevitably many of them will lose. “

Can this ultimately affect the entire ecosystem?

“This is absolutely true, because we are not only losing migrating animals, we are also losing interactions, which is really important for the functioning of all ecosystems.

“We know that in the Arctic, the food supply has been altered for both migratory and local predators, such as lemmings and voles, small rodents that create the base of the arctic food chain, which have gone extinct. in many places.

“This translates to higher predator rates for migratory birds, it affects predators that don’t have enough food and inevitably they perish too, so it spreads throughout the ecosystem.

“So it’s obvious that we humans are affecting all interactions in the ecosystem, which can have unknown and quite serious consequences for the entire ecosystem. “

Photo: Vojtěch Kubelka

What species has your research focused on and where are there species that we encounter here in the Czech Republic?

“Certainly, the species we meet are passerines, or songbirds, like flycatchers. We also have a lot of shorebirds here in the Czech Republic, birds that usually migrate through our regions, breeding far north or even here and wintering in the south.

“We don’t have large migratory mammals in the Czech Republic, like elk, but we do have a few bats that migrate through central Europe.

“There are several dragonflies that also migrate to our regions, a species of butterfly from the Mediterranean called Painted Lady, but again with global warming that could change in the future. “

Your current study is a comparative perspective of previously published research. Did you work directly in the field in some cases and what exactly was that research like?

“We worked on various case studies involved in this overview. We worked with shorebird nest predation, where we used previously published data.

“But for several other datasets, we really worked directly in the field, for example in the Lake Caspian region, or in Chukotka in Russia, but also in South Bohemia with the northern lapwing, which unfortunately have high rates. increasing predation.

“In the field, we mainly work with shorebirds, which means that we come to the breeding grounds and carefully observe their behavior, we try to locate the nest and with minimal disturbance, we observe the nest and let’s follow the result. “

Painted Lady |  Photo: JirkaSv, Wikimedia Commons, public domain

Finally, what exactly can be done to mitigate the changes?

“Our article is important from a point of view that we have really put in place approaches on how we can really help migratory species. We can start with direct protection of nests from predators and local management to improve habitats and from there move on to large-scale conservation from there.

“Migratory species are really fragile and sensitive to change as they depend on staging areas, wintering areas and breeding grounds and anything you take out of the chain can really have an impact on the whole. Population.

“We really need to focus our conservation perspectives throughout the life cycle of these birds.

“What is also very important is to cooperate between whole nations, because migratory animals have no borders. So if we want to save them, we have to cooperate and I’m sure these animals are worth it. sadness. “

Berta D. Wells