Dr. Anderson Feijó, a postdoctoral researcher at the Beijing’s Institute of Zoology of the Chinese Academy of Sciences, discusses his article, “Divergent adaptations in resource-use traits explain how pikas thrive on the roof of the world”, his current research, as well as advice for fellow researchers.
What’s your paper about?
Our paper aims to investigate if adaptations to live at extremely high elevations manifest in morphological traits that mediate environmental interaction.
Living at high altitudes is challenging in many ways given the low oxygen levels, cold temperatures, high solar radiation, reduced food supply, and high predator exposure. Yet, several groups of animals have successfully colonized and evolved in mountain areas.
Using pikas—close relative to rabbits that can reach altitudes up to 6200 m in the Qinghai-Tibet plateau—as a group model, we investigate cranial adaptations under extreme-elevation conditions. We found that high-elevation species have developed specialized skulls to explore distinct alpine microhabitats across the Qinghai-Tibet plateau. This high level of specialization coupled with a strong habitat preference likely reduces competition among sister species in areas where food is available only during a 3-month summer. During the short growing season, all pikas must build large food caches (called haypiles) to consume throughout the year.
Another amazing finding of our study is that high-elevation pikas originated from species that were dependent on rocks to shelter, but then evolved the ability to dig burrows. This new behavior allows them to explore areas along the entire Qinghai-Tibet plateau away from rock/talus formation.
In addition to cold and hypoxia tolerance, high cranial specialization, the appearance of burrowing habits, and strong niche separation explain how these animals overcame both biotic and abiotic alpine stresses. Our study has thus expanded our understanding of how pikas flourish on the highest plateau on Earth and become one of the symbols of Tibetan fauna.
What is the background behind your paper?
Species adapted to extreme environmental conditions often display multilevel, interdependent modifications—from genes to life-history traits—allowing them to cope with physical and biotic (competition, predation) stresses. As an example, in extremely hot and dry environments, desert mammals exhibit physiological mechanisms that optimize water conservation, nocturnal habits to avoid heat stress and cranial adaptations that enhance hearing and facilitate predator avoidance. Following the reasoning that life in stressful habitats requires multiple adaptations, we decided to investigate whether skull traits also help to explain the successful diversification of species in high altitudes.
What are the key messages of your article?
The key message of our study is that adaptations to extreme environments occur at multiple levels of organization (cellular, tissues, morphology, behavioral, lifestyle strategies), but can lead to distinct evolutionary trajectories depending on which selective forces they respond to. To fully understand the complexity of evolutionary and ecological strategies that allow species to survive under extreme climatic conditions we must study these distinct levels of organization.
How is your paper new or different from other work in this area?
Instead of looking at the genes and physiological adaptations that allow species to thrive in extremely high elevations, we decided to look at the morphology. In particular, we focus on traits that play a vital role in mediating environmental interaction and often reflect adaptations to species-specific habitat and ecological attributes. As a result of this new approach, we found that contrary to convergent physiological and biochemical adaptations exhibited by high-elevation species, pikas from the Qinghai-Tibet plateau show a greater degree of morphological specialization to distinct alpine microhabitats. This finding mirrors the results of our previous research, where small mammals (rodents, shrews and moles) at high altitudes show highly differentiated skulls and are less likely to colonize lower altitudes.
Where you surprised by anything when working on it?
Actually yes! At first, I was expecting to find similar morphological adaptations among mountain-dwellers. Previous studies have documented several cases of convergent changes (when distinct species show very similar adaptations) in skulls related to restrictive environments, such as deserts, aquatic and rocky lifestyles. Considering high elevations as a very restrictive environment one would expect a similar pattern. However, to my surprise, we found that those species living exclusively in high altitudes (above 3000 meters) show the most diversity of skull forms.
What are the big questions still to answer?
In this article, we used pikas as a group model. These cuddly animals originated at high elevations in the Qinghai-Tibet plateau. For the next step, it will be very important to study if the adaptations we found are also present in groups that have originated at low elevations and later invaded high mountains. Furthermore, I want to compare our findings with groups living in other mountain areas across the globe, such as the Andes in South America. These will be the next questions I want to answer.
What are you currently working on?
My current main project is to investigate morphological adaptations to high altitudes at three distinct levels. First, assessing populations of species widely distributed along mountain slopes. Second, studying species restricted at different elevation zones. Third, comparing adaptations among mountain-dwellers across the world.
One piece of advice for someone in your field…
My advice for young scientists is to find passion in their research. The daily life of a scientist is filled with many drawbacks and negative results (experiments that don’t go well, low capture rate of target species…). Without joy for your project, being a scientist can be very challenging. The other piece of advice is to remain open to what nature (through the data you collected) is telling you. Sometimes we feel disappointed if the results did not come as we anticipated, but if we keep ourselves open to new ideas, it could be more fascinating than we previously thought.
- Feijó, A., Ge, D., Wen, Z., Xia, L. and Yang, Q. (2020), Divergent adaptations in resource‐use traits explain how pikas thrive on the roof of the. Funct. Ecol. Manuscript. doi:10.1111/1365-2435.13609