'Birds are very sensitive to changes that ecosystems are experiencing'

Salvador Rebollo de la Torre is a full professor of Ecology in the Department of Life Sciences. In this interview he talks about the causes and consequences of climate change in birds. As an introduction Rebollo begins by stating that 'Human activity has always led to changes in the functioning of ecosystems (...) these changes, known as Global Change, have taken on a global scale over the past few decades affecting the entire planet'.

The changes are of such magnitude that some scientists consider that a new era begins in the history of the earth, the Anthropocene, where human activity is the main engine of change. Salvador keeps on mentioning that 'climate change is the most popular, but not the only: We are affecting other very important global systems related to the cycle of chemical elements on a planetary scale.With the structure and functioning of ecosystems and their capacity to host biodiversity, with the composition and landscape configuration (…) that's why, the answer of birds to climate change must be understood inside a wider changes stage'.

-How is climate change affecting birds?

Birds are a fundamental component of most terrestrial and aquatic ecosystems, as a result, they are very sensitive to changes that ecosystems are experiencing. Their flight ability allows them to respond faster to changes than other organisms. For this reason, they are excellent bio-indicators for estimating the magnitude and characteristics of climate change.

-Are migrations being affected?

Of course. Many migratory birds in northern Europe leave their breeding areas to spend winter at more southern latitudes, even reaching the African continent. The climate change is smoothing the winter temperatures of many European regions. Birds no longer move so far south, shortening the distances of their migratory movements.

Even some bird populations have become almost completely sedentary. The processes involved are complex. Not only climate change is involved, but also other processes such as land use change. For example, some bird species that have recently changed their migratory behavior are also affected by macro-agricultural projects that have profoundly transformed their classic African wintering areas.

-Are diseases emerging in birds as a result of climate change?

The connection between climate change and potentially pathogenic organisms is a fundamental issue because it has implications for animal health and public health. Some diseases that were more typical of latitudes situated more south on the African continent are increasing their incidence in European latitudes. Among these diseases, bird malaria stands out. Climate change is increasing in incidence because, among other reasons, it increases the abundance of the vector of malaria, a type of mosquito.

-What is avian malaria and what is it for? Which birds are they affecting?

Avian malaria, like human malaria, is a parasitic disease caused by a protozoan, a eukaryotic microorganism more complex than viruses and bacteria. It has a complex life cycle in the bloodstream and uses mosquitoes as its main vectors to infest vertebrates. Recently, an increase in avian malaria has been detected in urban sparrows in southern Europe. A similar phenomenon is already occurring with some diseases in humans.

-Are there bird species that are at risk because of the variation that is taking place in the climate system?

Yes, there are a lot of examples. Just as arid and semi-arid environment species are expanding their range to northern Europe as a result of climate change, species characteristic of colder environments are suffering a reduction in the area of their habitats. This occurs both latitudally and at altitude. For example, some bird species characteristic of high mountain environments are reduced in habitat due to climate change. Weather conditions are softening at altitude and that's reducing the peak surface with the cold environments these birds need.

The same process is causing ice loss at north latitudes and mountain summits and reducing the surface of glaciers. Specifically, in Spain, the reduction of Cantabrian grouse populations is related to these effects of climate change. Again, the cause of the decrease of this bird in Spain not only is climatic. Transhumant cattle kept pasture and scrub areas in high mountain areas serving as feeding habitats for the capercaillie and their chickens. Due to lack of grazing by extensive livestock, these grasslands and scrublands are replaced by more forester plant communities that have a lower abundance of insects at ground level, losing habitats fundamental to the reproduction of the grouse.

-What effects is climate change causing on birds living or migrating to our country?

The Iberian Peninsula is located in a strategic position between the European and African continent and is a natural laboratory for studying the effect of climate change on birds. The northern third has atlantic climate, which extends north to Europe. The rest of the peninsula is influenced by the Mediterranean climate, more typical of the Mediterranean basin and North Africa.

This position of the Iberian peninsula on a climate border makes it a very interesting territory to study the effects of climate change on birds. On the one hand, some European birds that wintered in Africa, now stay in the Iberian peninsula to spend the winter. On the other hand, the Iberian peninsula is where the first advances of birds of African origin that begin their expansion into Europe are best detected.

-Are new birds appearing in our country?

For example, as a result of climate change, some bird species characteristic of arid and semi-arid African environments are colonizing southern Europe and expanding their range to north such as black-winged kite or red-rumped swallow. The first populations of these species have been detected in the Iberian peninsula and maintain a higher density of individuals here. 

-What solutions can we put in place to protect our birds?

Solutions must act on the causes and consequences. On the one hand, to act on the causes we would have to substantially change the prevailing economic model, because it is a model that does not give sufficient importance to the environmental consequences of our style of production and consumption. Global and climate change are evidence that we are exceeding the capacity of natural systems to support the human activity. The existence of limits to the transformation of natural systems should be the starting point for creating more sustainable development models.

On the other hand, we need to act on the consequences of climate change. For example, we need to identify ecosystems and species most sensitive to climate change and develop conservation plans tailored to them. We also need to learn how to restore habitats that are degrading as a result of climate change.

The recent macro-fires we have observed in Australia (and in less measured also in Portugal and Gallicia) warn us from what is coming up with us. Large fires in Spain are more than likely to occur more and more frequently if average and extreme temperatures continue to rise and if droughts are escalating. These large fires that reach very high temperatures will affect the habitats of many birds and other organisms. This makes necessary to learn to restore these habitats after the fire. In this sense, it is essential that we take preventive measures to make forest masses less flammable. We need to control the most pyrophile tree and tree species and manage forest masses to reduce phytomase with silvicultural techniques and/or extensive livestock. We must prepare and manage forest masses to avoid the most dramatic consequences of climate change.

 

Publicado en: Inglés