Géraldine Hildbrand: Why some plants are better able to adapt to climate change

In this new post, Géraldine Hildbrand—Scientific collaborator, BFH-HAFL, Switzerland—presents her latest work ‘Above- and below-ground responses to experimental climate forcing in two forb species from montane wooded pastures in Switzerland’. She highlights the importance of ecophysiological traits, discusses the relevance of plasticity to cope with environmental changes, and explains how she can balance research while moving to teaching.

About the paper

It is undeniable that climate change is now underway. Ecosystems in mountain regions are particularly sensitive to these changes. What transformations will these natural environments face? How will plant communities evolve? The adaptation of these natural environments to future changes remains an important question.

The medium-altitude study site (credit: P. Vollenweider)  

By focusing on the study of so-called “soft” functional traits, large-scale assessment and ecological modelling of plant communities make it possible to understand and predict the responses of communities to climate change. However, there are still some big unknowns—one being which strategy will the species in these communities adopt? A mechanistic comprehension, including more and better targeted traits, is needed to understand why some constituent species show consistent differences in their responses to climate change.

We investigated ecophysiological and morpho-anatomical traits of the foliage and roots of two common perennial forb species (Taraxacum officinale and Alchemilla monticola) occurring in the same plant community of montane wooded pastures. These two species were subjected to simulated climate warming. This was achieved by transplanting pasture monoliths from Swiss wooded pastures adapted to cold temperature at high altitude to lower altitudes where the climate is warmer and dryer.

The two study species, Taraxacum officinale and Alchemilla monticola (credit: P. Vollenweider)  

About the research

Géraldine taking measurements in early spring (credit: P. Vollenweider)

We hypothesized that the two distinct species would show similar responses to the transplantation treatment. Our expectation was that we would observe specific morpho-anatomical adjustments to withstand higher water stress in the foliage and roots in reaction to decreasing rainfall and increasing temperature. However, we were surprised to find that Alchemilla did not respond according to our hypotheses. By increasing its size—a typical temperature effect—without raising its xeromorphic protection, this species showed maladaptive changes. Taraxacum, on the other hand, managed to address the multi-stress situation correctly and acclimate appropriately. The treatment responses of these two mesophilic species appeared not random, but in line with their respective ecology. Alchemilla, a mountain species—limited in its natural environment by cold temperatures—responded to temperature issues but was unable to cope with drought. Taraxacum, as a ubiquitous species, was found to respond “smartly” to the multi-stress situation.

Experimental design: several transplanted pasture monoliths(credit: P. Vollenweider)

Phenotypic plasticity allows species to cope with stress. However, these changes are governed by the specific ecology of each species. Some species may therefore be less resilient to climate change in a multi-stress situation, and this may lead to losses of plants more specifically adapted to montane conditions—as observed in other investigations performed in the framework of our experiment. Heightened competition between species due to shifting environmental conditions, i.e. with reduced coldness limitation but increasingly constraining water economy, should cause modifications in the composition of plant communities of mountain ecosystems in the future. To better predict these compositional changes, we need to know why there is such a wide range of responses and why some plants react appropriately to stress while others fail to adapt and even show inappropriate responses. With this information, we could improve the management of these ecosystems in a challenging future and hopefully curb biodiversity losses in tomorrow’s landscapes.

About the author

Géraldine Hildbrand (credit: P. Huber)

I was always fascinated by nature and its workings, so when the time came, I chose to study Biology. It became obvious to me that humans and all other organisms are part of a whole and that we need to understand these interactions with both the surrounding and global environment in order to predict outcomes in a changing world. For my master’s thesis—the basis of this publication—I joined a research team for a year and dedicated myself entirely to the field and analytical work. It was a very enriching time, during which I felt at the heart of research and progressed in my understanding of systems which fascinate me.

Research is a competitive world that offers little stability, something which did not fit my personal aspirations. Therefore, I turned to teaching. Teaching at a university of applied sciences (BFH-HAFL) allows me to stay in close contact with innovative researchers and to disseminate their work to my students, thus reaching a broader audience.

In my everyday professional life, I realize that our knowledge only gives us a partial understanding of nature. A lot of research is still needed for a more global understanding. This opens opportunities for future generations to work in various fields of research. However, there are also other career paths that can provide equally rewarding experiences. Teaching young students who are still open to all disciplines is very rewarding and contributes significantly to training new generations who will know how to take care of the planet. This fits perfectly with my fascination for nature and its functioning.

Enjoyed the blogpost? Read the research here!

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