K. Dana Chadwick: Peruvian Amazon

Nutrient Cycling & Rejuvenation in an Amazonian Terra Firme Forest

The interactions of biogeochemical and geomorphological processes

My dissertation work focused on understanding the role that hillslope processes play in determining the distributions of nutrients in soils and the subsequent organization of forest canopy characteristics. Terra firme forests in the southwestern Peruvian Amazon exist on terrace formations that were deposited by rivers flowing from the nearby Andes Mountians. Over time, the soils in these forests have experienced extensive leaching due to rainfall that exceeds 2.5 meters annually. This leaching results in depletion of essential rock derived nutrients, such as phosphorus and calcium. However, these landscapes evolve via streams cutting down through these terraces, removing nutrient poor surface soils, and potentially exposing sediments that retain a higher amount of nutrients. My work examined these dynamics in a terra firme forest to understand the role that the evolution of these landscapes plays in biogeochemical cycling and ecosystem organization.

Findings & Highlights

May 16, 2018

Behind the Paper

I was asked to contribute a Behind the Paper blog post to Nature Research Ecology and Evolution's Community forum. It was fun to reflect on all the people I had the pleasure of working with and the field experiences that made the work presented in our Ecology Letters paper possible.

April 16, 2018

Paper: The Role of Landscape Evolution

The final chapter from my dissertation work has been published in Ecology Letters. It was so exciting to see the understanding I developed in the first two chapters come together to make this work possible. (pdf)

August 16, 2016

Highlight by Stanford Daily

I was interviewed by the Stanford Daily to discuss my work on landscape biogeochemistry and experiences in the Earth System Science program at Stanford. Happy to share my experiences with the student-run paper.

January 23, 2016

Paper: Crown-level Foliar Trait Mapping

Our paper utilizing partial least squares regression to predict crown-level foliar characteristics across the terra firme and floodplain forests at CICRA has been published in Remote Sensing.

January 20, 2016

Paper: Hillslope Controls on Soil Nutrient Distributions

Our paper on the role of hillslope and biotic processes in controlling the distributions of nutrients across the terra firme landscape in the Los Amigos Conservation Concesssion was published in Biogeochemistry. This was my first first-authored publication! (pdf)

About

Study Area

Los Amigos Conservation Concession

For these studies I had the privilidge of conducting field work at the CICRA Biological Station within the Los Amigos Conservation Concession, part of the Amazon Conservation Association. The station is located at the confluence of Rio Madre de Dios and Rio Los Amigos in the southern Peruvian Amazon.

Acknowledgements

So many amazing people helped me to complete this work, I would be remiss if I failed to acknowledge them here. First and foremost, my advisor Greg Asner, who gave me so many wonderful opportunities to develop as a scientist and a leader. I am indebted to the amazing field assistance of Raul Tupayachi, Felipe Sinca Cansino, Katie Kryston, Hernan Collado Delgado, Marlon Guerra Vargas, Ediberto Torres Lacuta, and especially Rufo Bustamante Collado. I also had a wonderful team of undergraduate researchers who worked with me in the lab, Scott Roycroft, Lucas Del Toro, and Heather Herman. Finally, I was privilidged to have the support and guidance of my amazing committee members: Chris Field, Scott Fendorf, and Peter Vitousek. I was also fortunate to receive support from the NASA Earth and Space Science Fellowship program.