Our Projects
Growing Resilient Forests
How does the functional diversity of restoration plantings shape early forest recovery and long-term resilience? Since 2021, we have been testing this question across four tropical forest ecosystems in Costa Rica. Our experimental plots span a gradient from monocultures to mixtures of up to twelve native tree species, selected for contrasting traits in growth strategy, resource acquisition, and life history. This design lets us separate the effects of functional diversity from species richness alone. By measuring vegetation structure, seed rain, soil and litter biodiversity, bird communities, and soil nutrient dynamics, we aim to provide evidence-based guidance for designing resilient, functionally diverse tropical forests.
Testing Novel Soil Amendments
How can soil amendments make tropical forest restoration more effective and affordable? Working across highly degraded former pastures, we are testing innovative soil amendments—including agricultural byproducts such as coffee pulp and fruit peels, native soil microbiome inoculations, and biochar—and comparing their performance with conventional restoration practices. Using a diverse range of native tree species, we are evaluating how these amendments influence tree survival, above- and belowground growth, carbon storage, and restoration costs. Our findings will help identify cost-effective strategies to restore degraded soils, accelerate forest recovery, and improve restoration outcomes.
Taking the Pulse of the Global Restoration Movement
As global efforts to restore degraded ecosystems move forward under the UN Decade on Ecosystem Restoration, understanding how restoration and conservation happen on the ground is essential for improving its effectiveness and long-term impact. Working with colleagues at ETH Zürich, the Branch Institute, the Missouri Botanical Garden, and conservation organizations across Latin America, we are examining the realities of forest restoration in practice: how practitioners design and implement restoration projects, the scale and characteristics of the growing restoration workforce, and how much of the diversity of native tropical trees is represented in tree planting efforts. By identifying gaps in knowledge, skills, and current practices, this research aims to strengthen the scientific foundation for more effective, diverse, and scalable forest restoration.
Managing Invasive Ginger in Tropical Forests
The invasive ornamental ginger Zingiber spectabile is spreading through tropical forest understories in southern Costa Rica, potentially threatening native plant communities and forest recovery. Our research examines how this species invades primary and secondary forests, its impacts on native vegetation, and the effectiveness of different control methods. Building on our initial findings, we have recently established a new long-term experiment to test improved strategies for controlling invasive ginger and assess how its removal affects the recovery and diversity of native understory plants over time.
Predicting Glacial Flood Hazards
As climate change accelerates glacier retreat in mountain regions worldwide, expanding glacial lakes pose growing risks of catastrophic outburst floods to downstream communities. In Peru’s Cordillera Blanca, the retreat of the Vallunaraju glacier has formed a lake contained by a natural moraine dam whose stability remains uncertain. A sudden dam failure could threaten thousands of residents in Huaraz and surrounding communities. To better understand and reduce this risk, we are using innovative, non-invasive geophysical techniques and automated lake-depth surveys to assess the dam’s internal structure and stability. The resulting data will inform predictive models of potential dam failure, providing critical scientific evidence to guide disaster preparedness and protect vulnerable mountain communities.
This research is carried out in collaboration with researchers at Universidad Nacional Mayor de San Marcos, Lima, Peru.
Impact of Air Pollution on Glaciers
Climate change is warming the Andes and shrinking Peru’s glaciers, but rising temperatures are not the whole story. Air pollution, including black carbon and dust, darkens snow and ice, increasing sunlight absorption and accelerating melting.
For 15 years, dedicated Peruvian students and collaborators have collected regular measurements throughout the year at several glacier sites across Peru. Pollution levels vary dramatically, from undetectable amounts to glacier surfaces that are nearly black. This remarkable variability demonstrates why long-term monitoring is so important: occasional measurements simply cannot tell the whole story.
These observations provide a valuable opportunity to investigate where the pollution originates, how it reaches remote mountain glaciers, and where and when reducing air pollution could help slow glacier loss.