But tragically, they continue to make the often grueling and energy-guzzling journey every year.

Every year, many animals, including mammals, birds and insects, prepare themselves for a considerable war of attrition. They migrate north for long distances to breed here, as well as to take advantage of the seasonal abundance of food, reduced parasite and disease presence, and relative protection from predators. However, researchers have a new study discovers that this grueling trek due to climate change and human pressure may no longer be worthwhile for some species. But how do you tell them that?

Long distances

Among the animals that prepare for an impressive migration each year are caribou, shorebirds and monarch butterflies, which travel more than 1000 kilometers in summer to northern temperate and arctic regions. In winter they then return to the south. Such migrations are certainly not going to bother them. These are often harsh and energy-guzzling journeys. However, the benefits have still outweighed the benefits. However, researchers are now warning that this is no longer the case for many species.

Hollowed out

In the study, the team looked at 25 recently published studies describing how exhausting migrations no longer pay. According to the researchers, it means that the benefits of such treks have been eroded. How come? Climate change and human pressure, they say. And that has in many cases led to lower reproductive success and higher mortality among migratory species.

safe harbors

According to researcher Vojtěch Kubelka, the findings are alarming. “We’ve lived with the idea that northern breeding grounds are safe havens for migratory animals,” he says. “But now we see that numerous areas of temperate climate are ecological traps.” The food supply and availability in the north often no longer corresponds climatically to the reproduction of migratory animals. And that leads to more mortality among offspring, especially among migratory birds. In addition, new parasites and pathogens are emerging in the Arctic, creating new pressures. In addition, apex predators are increasingly targeting nests and eating the eggs and chicks before they have a chance to fledge.

Foxes eat eggs more often
Predators such as foxes used to hunt voles in the Arctic. But due to today’s milder winters, we are seeing striking changes. Due to the warmer climate, rain falls on snow more often, which then freezes again. This prevents voles from reaching their own food. With fewer voles in the area, foxes eat the eggs and chicks of migratory birds instead. In the past 70 years, the number of migratory bird nests plundered by predators has tripled. And that is mainly due to climate change, the researchers argue.

So it seems that the time when migration paid off for some species is now really over. But how do you tell them that? Tragically, many continue to make the often grueling and energy-guzzling journey every year. While some animals might be fine traveling a little further north to overcome the drawbacks, most draft animals are still determined to make the grueling journey each year.

What to do?

The researchers suggest that Arctic and northern temperate breeding areas, in particular, need significant conservation attention. In order to shape this properly, the researchers propose to accurately map the stressors for draft animals. In this way we can better distinguish between suitable breeding areas and degraded environments. “The recognition of emerging threats and the proposed classification framework will help identify the most threatened populations and regions,” said Kubelka. “This allows us to take better targeted conservation measures.”

That will not be an easy task, however. Coming up with solutions will probably be difficult because of the large areas involved. However, doing nothing is not an option either. Because current trends may have serious consequences for the structure and function of ecosystems. “The Earth is a complex ecosystem,” said researcher Tamás Székely. “Changes in the extent to which migrations pay affects the population of migrating animals. And that in turn can have consequences for species composition, food webs and ultimately the entire ecosystem.” The researchers therefore emphasize that more research is needed to get to the bottom of this problem.