Research Spotlight: Linking landscape evolution with foliar traits in Bornean forests

K. Dana Chadwick and Gregory P. Asner (2020). Geomorphic transience moderates topographic controls on tropical canopy foliar traits. Ecology Letters. 

The Upshot

Tropical forests contain some of the most biodiverse and dynamic ecosystems in the world. Environmental conditions such as precipitation, temperature, and soils shape the biota of the landscape. This influence is especially noticeable when comparing the towering trees found in low elevation forests to the hardier, shorter ones found at the top of tropical mountains. Together, these factors create an ever-changing and heterogeneous ecosystem, with each niche harboring different species of uniquely adapted trees.

Scientists have sought to understand the links between geology (the rock types that soils originate from), biogeochemistry (feedbacks between environmental conditions, nutrient cycling, and plants), biodiversity (the variety of life in an ecosystem), and biogeography (how trees are distributed across a landscape) to paint a more complete picture of how life coevolved with our planet. Using tree chemistry maps created by ASU’s Global Airborne Observatory, high-resolution topography data, and computer models, researchers at Stanford University and Arizona State University’s Center for Global Discovery and Conservation Science uncovered new insights into the processes behind how life coevolved with our planet.

The Discovery

The study analyzed data from Mt. Kinabalu in Malaysian Borneo—a 4,095-meter high mountain harboring a wide diversity of trees across topographically varied terrain. The maps included the concentrations of nutrients in the tropical forest canopy as well as the structure and architecture of the trees. This provided the researchers an unprecedented look at the forests of Mt. Kinabalu and its remote complex terrain.

The researchers discovered that leaves from trees contained different amounts of nutrients depending upon both the elevation and geology of its environment. Along hillslopes, from ridge to valley, trees contain more nutrients while their ability to capture and utilize sunlight also increases. The researchers found that this trend was significantly impacted by changing erosion rates, highlighting the important role erosion plays in distributing fresh nutrients to the soil. 

The Impact 

“The discovery of such strong and beautifully complex geologic control on forest composition gives us new insight into the fundamental make-up of Bornean forests, in ways that inspire even more exploration,” said Greg Asner, author of the study. 

The Researchers

Dana Chadwick is a postdoctoral researcher at Stanford University. Greg Asner is the director of the Arizona State University Center for Global Discovery and Conservation Science.