Climate change shifts areas summer breeding North American birds, reported in a study in the journal Proceedings of the National Academy of Sciences. While some species are beginning to explore new territory, the nesting habitats of other species are reduced, which in the future may lead to their extinction by the end of the XXI century.
Over the past half century the number of birds in North America has decreased markedly: estimates showthat the number of individuals has decreased by almost three billion. Although these changes have affected most of the major biological communities and taxonomic groups, the researchers noticed that while the population size of migratory species decreased, the size of the population wintering on the continent of birds, on the contrary, slightly increased. Such a sharp contrast, according to scientists, suggests that these groups are exposed to different threats, and their ability to adapt to changing environmental conditions may be very different.
Scientists led by Clark Rushing (Clark S. Rushing) from Universitat of Utah decided to find out how the observed trend can be related to the increase in the average annual temperature in North America. Ornithologists have collated data Breeding Birds Survey, one of the oldest and longest-running citizen science programs in the world, which contains information about the migration of birds in Canada and the United States over the last 50 years, with data on climate change. Based on this, researchers created a model that shows how has changed the breeding habitat for the 32 species of birds native to Eastern North America.
It turned out that birds that breed and winter in North America between 1972 and 2014 have increased the range of their migrations, gradually mastered the more Northern regions. However, they retain the southern territory, thus extending its breeding range. The authors believe that this suggests that species such as Carolina wrens and red heads of woodpeckers, it is easier to adapt to climate change.
At the same time, the latitudinal distribution of Buntings, grackles and of other Neotropical species that fly to spend the winter in the Caribbean Islands, Central and South America, on the contrary reduced. The Northern border areas of the summer breeding these birds is not expanding, despite the fact that in the South, on the contrary, they shifted to the North. In this regard, the study’s authors fear that if this trend continues, some species may be on the verge of extinction by the end of this century.
The observed difference between the behavior and the Neotropical species, according to ornithologists, can be explained by the fact that the latter requires a lot of energy for long migrations. In tropical areas in recent years increasingly observed drought, so the birds may simply not be enough food to be forces for the development of new territories in the North.
The researchers also noted that the species whose population increases are also more likely expanded the boundaries of the nesting area to the North, while species with declining population tended to reduce their southern border. These results are consistent with the results of previous studies and confirm the positive relationship between population trends and ability to adapt to climate change.
In 2018, scientists published a large report about the risk of decline of populations of animals, insects and plants on Earth, with the rise of average temperature by 1.5 and 2 degrees Celsius. It turned out that by limiting the temperature increase to 1.5 degrees, the risk of decline of populations of different species will be considerably less.