The capercaillie, an emblematic species of mountain habitats, is disappearing in Spain and some studies suggest this is due to its low reproductive success. Although the common subspecies is quite common throughout Eurasia, in our country Fewer than 1,500 specimens survive of the two peninsulas.
In the specific case of the Pyrenean capercaillie (Tetrao urogallus aquitanicus), which occurs in Catalonia, Aragon, Navarre, Andorra and the French Pyrenees; Their natural habitat is black pine forests (Pinus uncinata) and its population in Spain is small. This means that, as with the Cantabrian capercaillie (Tetrao urogallus cantabricus), is considered critically endangered according to the Spanish Catalog of Endangered Species.
Several Spanish institutions, led by the Animal Health Research Center (CISA, INIA-CSIC), have carried out the first health study of the species and found that 62.5% of capercaillies in the Pyrenees are infected Blood parasites of the genres Hemoproteus And Leukocytozoon, related to avian malaria. In addition, they identified a herpes virus for the first time in four of these birds.
In order to create appropriate protection plans, it is important to know which infectious agents affect wild populations
“Knowing which infectious agents affect wild populations is crucial for drawing up appropriate conservation plans, especially when making decisions about translocations between different population centers or the reintroduction of animals born in breeding centers,” he tells SINC. Carlos Sacristan YagüeResearcher at CISA-INIA-CSIC and last author of the paper.
“It is important to always keep in mind that when we transport an animal, we are also transporting the infectious agents that it carries and that the target populations may not have immunity to them,” adds Sacristán Yagüe. The results will be published in the journal Scientific reports.
In addition, scientists have noted the lack of genetic material of various pathogens (Newcastle virus, Escherichia coli, Salmonella sp., Campylobacter jejuni And Chlamydia psittaci) in the 30 samples of fresh capercaillie droppings analyzed.
“It is crucial to clarify possible causes of disease and the factors that determine them in order to be able to carry out more targeted and effective protective measures,” adds the expert.
Knowledge about the health status of wildlife populations at risk of extinction, such as the Great Pyrenees capercaillie, is crucial
For Olga Nicolas de FranciscoSpecialist wildlife veterinarian and lead author, “knowing the health status of wildlife populations at risk of extinction, such as the Great Pyrenees capercaillie, is crucial to prioritizing conservation measures.”
So much Hemoproteus as Leukocytozoon They are hemoparasites that are transmitted by vectors, in the first case mainly by insects of the genus Culicoides and in the second case by blood-sucking black flies. “The discovery of their presence in Great Pyrenees capercaillies was a surprise, as they are mountain birds living at high altitudes, where we expected that the vectors that transmit them would be absent or present at low densities,” says Sacristan Yagüe.
Specimen of a Cantabrian capercaillie (Tetrao urogallus cantabricus). /Wikipedia
Climate crisis and transmission vectors
To conduct the study, the researchers took advantage of the opportunity regular catches in the Catalan Pyrenees to tag specimens (previously with a radio transmitter, now with GPS) and carry out their monitoring, finding out their distribution, behavior and threats.
In recent years, the authors performed veterinary examination on these captures and collected blood, oropharyngeal and cloacal samples for pathogen analysis using PCR; They also took tissue samples from Great Pyrenees capercaillies found dead in Catalonia and Andorra.
Finally, they prioritized the use of non-invasive methods To determine the presence of relevant pathogens in feces, fresh remains are collected from more than two years in the forests where they are still found.
We know that other vector-borne pathogens are increasing their spread due to global warming and can affect birds.
Although further studies are needed, scientists do not rule out a link to climate change in the spread of these diseases, as the Pyrenees are among the areas where the incidence has increased the most. medium temperature in recent years – at least 1.2 ºC between 1949 and 2010 – and this favors the spread of the vectors.
“We know that other carrier-borne pathogens may increase their spread due to global warming and affect birds, as is the case with West Nile virus or.” Plasmodium relictum“says the researcher.
The latter is a single-celled parasite that is considered one of the main causes of avian malaria. “This disease is not transmitted to humans“But it can have dramatic consequences for birds, especially for birds that have not co-evolved with this parasite, such as birds from certain islands or from dry climates where the mosquito that transmits this parasite is absent,” emphasizes Sacristán Yague.
The possible effects of the discovered hemoparasites on Great Pyrenees are not yet known, but previous studies know that they can cause anemia and even death in other bird species.
Annual cycle of the capercaillie. / Paisatges Vius Foundation
The first herpes virus in capercaillie
The herpes virus discovered is likely a new species, first detected in capercaillie, and is related to those that cause respiratory diseases in domestic birds.
“Is new in science, but it has certainly been infecting these animals for thousands of years, since these viruses generally evolve along with their hosts. “From what we have observed in the course of our research, virtually all species have their own herpes viruses,” they say.
It is important to remember that there is still a great diversity of species in the animal world lack of knowledge about pathogens that concern them. For this reason, the team emphasizes the importance of conducting research capable of detecting new pathogens and thus expanding knowledge about the pathogens found in the natural environment.
“Despite the endangered status of the species, Recovery is still possible. There are clear examples of how establishing intensive and targeted conservation strategies can restore populations of wild species, as in the case of the Iberian lynx, even when they were extinct in the wild, such as the European bison or the pole-footed polecat. Black,” emphasizes Sacristán Yagüe.
Also involved in the work were technicians from the Generalitat of Catalonia and the Conselh Generau d’Aran, the European University of Madrid, the University of Barcelona, the University of Lleida and the Pyrenees Institute of Ecology.
Human activities that disturb them
In the Iberian Peninsula, capercaillies are mountain forest birds and serve as indicators of the health of the ecosystem in which they live, as they are very fragile and have limited ability to move.
Among the main threats they face, in addition to the change and degradation of their habitat, climate change or the increase in ungulate populations, is also the stress caused by the presence of humans during the fungal season or winter Mountain sports activities such as off-piste skiing and snowshoeing.
Programs are currently being carried out to delineate preferred areas for the species, inform the population about the annual cycle of these birds and even provide guidance on their whereabouts in some natural parks and recommend alternative routes to avoid these areas.
Nicolas de Francisco SINC assures that ski slopes can have an impact on the Pyrenean capercaillie: “Previous studies in alpine areas have shown that the presence of skiers, especially off-piste and in the forest, is a cause of stress for the species.” Currently, at the facility or expansion of ski slopes, the presence of this bird is taken into account as one of the limiting factors in the environmental impact analysis.”
On the other hand, those that are already in operation and include forests where capercaillie live are carried out Dissemination and signaling measuresto inform users of best practices they should follow.
The team’s next steps will aim to increase the number of animals sampled and analyzed. In this way, clinical signs of disease could be associated with infection by this virus and one could know what symptoms they cause and even observe associated lesions.
In addition, they believe it is important to study larger numbers of animals from different populations to find out whether the herpes virus is already present in all of them. “If we manage to minimize the stress to which the capercaillie is exposed by improving the quality of its habitat, we will already reduce the potential impact of this virus on the species,” concludes Sacristán Yagüe.
Sacristan C et al. “First detection of herpes viruses and hemosporidia in the endangered Pyrenean capercaillie (Tetrao Urogallus Aquitanicus)”. Scientific reports