Niko Carvajal Janke – Harper Prize Shortlist

Throughout April, we are featuring the articles shortlisted for the 2021 Harper Prize. The Harper Prize is an annual award for the best early career research paper published in Journal of Ecology.

Niko Carvajal Janke et al.’s article ‘Evidence for a fungal loop in shrublands‘ was one of those shortlisted for the award.

⭐️About me

My excitement for ecology research solidified during my undergraduate internship with the National Science Foundation’s REU program. I spent my sophomore summer in Puerto Rico, helping the then PhD student Dr. Daniela Yaffar characterize the mycorrhizal colonization rates of the 5 most common woody tree species on the island. It was my first experience visualizing the community interconnectedness that many ecosystems have, and to this day I remain inspired by that understanding. This led me to focus my thesis on the understudied fungal loop hypothesis. The fungal loop hypothesis investigates the potential for plant communities in dryland and desert systems to share nutrients through networks of fungal symbionts in the soil, much like the relationships seen between fungi and plants in tropical and temperate forests. At the time, there were no academics studying the fungal loop hypothesis at my school in Middlebury VT, USA (nor were there any deserts within my half of the country to visit). However, my thesis advisor Dr. Kirsten Coe allowed me to independently design my project. I then consulted microbiology, geology and biology professors to design a thorough sampling method, secured funding through grants, purchased all of the relevant equipment, secured permits for sampling in the Sonoran desert of Arizona, USA, and obtained a method to bring DNA samples across the country by road.

While I knew that I loved plant-microbe interactions, I wanted to use the inherent transition of graduating college to experience tangential fields from dryland ecology. In doing this, I planned to gain perspective on what I love about the field, while simultaneously diversifying my skill sets and exploring the world before continuing my education. I spent the summer following my graduation publishing my thesis, while also participating in an internship with the Blue Marble Space Institute of Science, where I worked with a small team researching sustainable closed-loop plant microbiomes for crops on the International Space Station. This was when I decided I would be forever studying plant-microbiome systems, but I still hadn’t decided on which!

Following the summer of 2020 I began a year-long research position with the Viticulture and Enology department at the University of California, Davis. Working under Dr. Forrestel, I studied the phenological and physiological basis for heat and drought responses in grapevines, and how to harness these relationships to address the potential impacts that climate change may have on viticulture practices, and ultimately, wine quality. I had been interested in the wine industry for a few years at that point, and following my position in the Forrestel Lab, I decided that applying my passion for plant-microbe interactions to addressing sustainability and climate change in the wine industry would be a perfect synergy of these two passions. I am planning to pursue a graduate degree in Viticulture and Enology after spending a few years saving money, and learning more about the current environmental standards and challenges present in the industry. I currently work full time at Dakota Shy Winery in Napa Valley, CA, where I have the privilege of learning the science, chemistry and art behind some of the best wines in the world.

🔎About the shortlisted paper

The fungal loop hypothesis, largely coined in response to Green et al., 2008, suggests that soil fungi acts as a nutrient exchange conduit between disparate and spatially isolated producer communities in dryland ecosystems. Fungal loop studies have characterized the presence of these nutrient exchange networks in the drylands of Europe, Asia, and North and South America, where the interruption of these connections can lead to changes in dryland community composition. However, many of these studies have varied in methodological practices, making it hard to compare some findings to others, or to deem a study’s results as conclusive. 

In a North American arid shrubland, nitrogen was transferred from moss-dominated biocrust patches (A) to nearby Larrea tridentata shrubs (B) and spatially isolated biocrust patches. This process was likely facilitated by dark septate endophyte fungi (C) which reestablished subterranean nutrient exchange pathways between community members through mycelia up to 6 days following a pulse rainfall event. Figure Credits: Dr. Kirsten Coe, Middlebury College, Middlebury, VT.

The objective of my study was to create a clear workflow for characterizing the presence or absence of a fungal loop within a defined community. I tested this workflow out in the Sonoran desert of south-central North America, and identified the presence of a nutrient exchange pathway between dryland producers in a novel ecosystem, shrublands. This pathway would have likely been missed following sampling protocols of previous studies, where a shorter sampling window would have obscured the delay in nutrient translocation I observed. I also found that one fungal loop community member, moss-dominated biocrust, was capable of translocating nutrients between isolated patches, potentially suggesting that biocrusts could act as a cohesive stabilizing sink for biologically available nutrients within a given community. My findings address the potential impact of droughts and precipitation size on the successful identification and directionality of fungal loops, and propose the importance of a variety of contextual variables in denoting the dimensions of a fungal loop within a community. 

In showcasing the role fungal loops play in shrublands, my paper considers how fungal loops could be an understudied but ubiquitous and considerable source of nutrient partitioning and storage within already fragile dryland ecosystems. I hope my paper will act as a stepping stone to standardizing the exploration of the fungal loop hypothesis on a global scale, and will encourage the utilization of fungal loops to mitigate the impacts of climate change and desertification in these ecosystems.

Find Niko at nikocarvajal.com (website coming soon).

Read the full list of articles shortlisted for the 2021 Harper Prize here.

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