Camila Medeiros—a post-doc at University of California Los Angeles, USA—presents her work ‘Predicting plant species climate preferences on the basis of mechanistic traits’. She discusses the connection between traits and niches, shows how to do ecology with small budgets, and highlights the need to transfer scientific knowledge to general audiences.

About the paper

By using mechanistic traits, our paper improves the ability to predict plant species’ climate niches. We focus on a gradient of aridity in the California Floristic Province (including Baja, Mexico) as a study system. We also zoom in to define how to measure the “mismatch” between plant species’ traits and their climatic niche. Furthermore, we consider how this mismatch can depend on the ecological phenomena, as well as identifying methodological limitations. We consider factors such as the fundamental and realized niches—the variation in microclimate that is not captured by macroclimatic patterns—and trait plasticity across sampling locations. One area we especially emphasize is improving standard trait measurement methodology and selecting mechanistically informative traits.

When I applied for my PhD at UCLA, I was working on my master’s project quantifying the impact of the removal of the leaf epicuticular wax on photosynthetic rates of a plant species native to the Brazilian Caatinga. This project involved the measurement of physiological traits to assess leaf health, but we were not able to accomplish all we planned due to a lack of appropriate equipment. So, when I started my PhD at UCLA, I wanted to work on a project that would give me the opportunity to learn high-impact techniques with broad applications. My passion for dry forest ecology and the mechanisms plants use to withstand and survive drought, motivated the idea to research the relationship between traits involved in drought responses with climate across a gradient of aridity in California. The fact that plant traits are adapted to climate worldwide has been known for millennia, but the actual use of physiological traits to predict where plants prefer to live climatically—and their sensitivity to changing climate—has proven very rare. Given that virtually all California plant species are under threat from climate change—similar to species from the Caatinga—the ability to predict plant species’ climate preferences and their vulnerability to potential climate change through the ‘language’ of their leaf and wood traits was an exciting question to pursue. Additionally, this study provided the potential to develop novel applications for plant conservation under climate change and for modeling climate change impacts.

Many ideas that inspired this paper emerged from discussion of the controversies in plant functional ecology regarding the relationships between functional traits and climate, or even of plant growth and climate. We thought that with rigorous approaches, stronger signals could be found to help resolve these controversies and shine new light. We decided to do an in-depth exploration into the relationship of traits with climate across diverse species. Then, by flipping the axes, establish a way to estimate species’ climatic niches from traits. We see so much untapped potential to use species physiological traits in this way, which is currently not done in any pervasive way.

To our knowledge, our paper is the first to explicitly attempt to predict species’ preferred climates from their mechanistic traits. We hope our approach will provide higher resolution for studies of species evolution and ecology, and also that it will inform conservation and climate change mitigation applications. We believe that our work can contribute to the prediction of patterns of distribution of plants under novel climatic conditions given their physiological traits.

We want our paper to reach a wide audience of plant ecologists and ecophysiologists. Equally, we are conveying the message that plants have strong climate preferences built into their leaves and wood, and we’d like that message to reach anyone who can use it, including policy makers and restoration ecologists and anyone interested in the ecology of Californian native plant species. During the process of preparation and publication of this paper we asked colleagues in land management and restoration ecology about the current disconnect between the huge amount of functional trait data and research, and its application to decision-making in species and resource conservation around climate change. Everyone seem to be clamoring for more straightforward ways to bridge these fields. We designed this paper to highlight important bridges.

About the research

Our paper shows how traits can be used to improve estimation of species’ climate preferences. The approach can be applied to global vegetation and earth system models used to predict climate change impacts on species and biomes, and their feedbacks on the climate system—an urgent priority in global change research. The paper also shows a path forward for the incorporation of functional traits into conservation/restoration efforts, as managers can calculate the mismatch of a threatened species’ from its optimal climate to improve resolution of the level of threat. This information would be useful to improve the designation of ex-situ conservation sites, matching the most vulnerable species to their climate niches and facilitating ‘assisted migration’.

Completing this huge field and lab study and sampling plants all over California was quite the challenge! We had limited funding and a big plan, so we counted on the help and commitment of multiple colleagues to make it feasible. We were able to sample all six sites with a lot of help from site managers and friends. Figuring out the species to sample and locating and collecting them wasn’t always easy—we aimed to include the most common species but many sites currently lack vegetation structure data. Also, processing this large set of traits for so many species within a tight timeframe was also quite challenging. We hope that, by presenting the value of this work and detailed methods, we are making it much smoother for future researchers to implement this kind of detailed mechanistic trait work in communities around the world.

Despite the difficulties, many things surprised me while working on this research! For example, many species were very different than expected in their drought tolerance traits, such as wilting point. I was also very surprised and impressed by the high diversity of ecophysiological strategies in a single site, as you can see in our desert site (pictures below)!

Now, we really want to put our findings to the test in a follow-up paper where we use key mechanistic traits to predict future species distributions. We also hope to continue developing concepts and tools to predict the outcomes of plant performance, community dynamics, and species distributions, using robust physiological parameters at the species level. Our study provides one avenue. Integrating species-specific trait data into species distribution models including large scale datasets is still computationally challenging and the availability of more time consuming/difficult to measure traits is still lower than ideal, but improving fast.

About The Author

I began my career as a plant physiologist, testing sugarcane photosynthetic efficiency and tolerance to abiotic stresses—such as drought and salt—for production in sub-optimal land to reduce the expansion of deforestation to pristine areas. After this first project, my interests shifted to more ecological questions, as a good part of my background readings involved aspects of applied ecology and social justice. I come from the Brazilian northeast—home of the Caatinga—which is a very unique tropical dry forest ecosystem that occurs exclusively in Brazil and hosts an incredible diversity of plants that endure drought, and survive and grow in nutrient poor soils. The study and preservation of dry forests is very important to me and to the livelihood of many people in my community. Currently, I am a postdoc at UCLA.

My first inspiration to go to college for Biological Sciences was Mayana Zatz, a Brazilian geneticist who studies the genetic basis of muscular dystrophies. I was fascinated by her work and inspired by the impact of her body of work on people’s lives. I’ve always been curious and studious, and wanted to pursue a profession where I would be able to make a difference to society. Dr. Zatz inspired me to pursue a career in science, but it was Isabel Cristina Machado—a legend of the pollination research in the Brazilian Caatinga—who got me to fall in love with Plant Biology during my first semester in college. She opened the doors to a whole new way of seeing nature, and instilled in me a curiosity and admiration of the many shapes and strategies plants are able to develop in order to survive adverse conditions.

I love being a scientist, but academia isn’t always easy to navigate. While I was an international student in the US, for example, I faced discrimination and bias like I had never been subjected to before. Situations that ranged from upsetting, such as being completely ignored in meetings and workshops unless I was introduced and included in the conversation by my faculty mentor, to instances that were effectively detrimental to my career progress, such as not being eligible for many funding calls that would be appropriate for my research because I am not an American citizen.

My biggest piece of advice, especially for students and early career folks, is to invest time and energy in activities independent from your academic passions. Dedication to your loved ones and personal development is important too! And for the ecologists out there: there’s so much beauty and wonder in nature and we should appreciate it every day even when we are so busy focused on our analyses. Some of the most interesting research questions and discussions I’ve had were inspired by observations of my surroundings during hikes, including the beautiful and mind-expanding sampling campaigns for this study.

Enjoyed the blogpost? Read the research here.