dr. MT (Masha) van der Sande

Tropical forests are of global importance. Unfortunately, they face increasing treats, such as wildfires and land use pressure. I am interested in understanding forest resilience to such disturbances across time and space. My core research focuses on two projects:

1. Past, present and future fire resilience of Amazon forests

Past fire resilience. Since human arrival to South America (at the end of the Pleistocene), fires have been part of the landscape. In this research, we assess how past fire regimes, climate change and human activities have influenced tree abundances. We do so using (available) fossil pollen, charcoal, and climate datasets to quantify shifts in tree taxa abundances throughout the Holocene across the Amazon. To better understand the mechanisms of how and why taxa differ in their responses to these changes, we quantify functional traits associated with fire tolerance, climate change, and human use. PhD student Thomas Meerwijk and postdoc dr. Nina Witteveen work within this research line.

Present fire resilience. Current and predicted future fire regimes, however, have become more frequent, intense and widesprea. This is a problem, as very few species are adapted to fire and, hence, face high mortality. In our research, we assess the resistance and recovery (together defining resilience) of different Amazonian forest types (seasonally dry and evergreen wet) to fires. We do so using:

a) a permanent plot monitoring network across the seasonally deciduous dry and wet evergreen forest in Bolivia, along gradients of fire frequency and intensity. Using this network, we assess resistance (i.e. the direct impact of fire) and recovery of forest structure, composition and diversity, and the role of fire frequency and intensity. PhD candidates David Pacuk and Samuel Pastor work within this research line.

b) a tree-level fire experiment, where we expose trees to experimental stem heating while monitoring growth, hydraulics, energy balance, etc. This allows us to understand the mechanisms by which fire impacts trees and how this differs among species and forest types. PhD candidate Nicole del Greco works within this research line.

Future fire resilience. Bringing together what we know from past and present fire resilience, we aim to adapt a dynamic spatially explicit model built by dr. Jorad de Vries, to predict the impact of future fire regimes on Amazon forests.

2. Secondary succession and restoration of tropical forests after agricultural land abandonment

Secondary tropical forests cover large areas and have great potential to recover biodiversity, carbon, and other ecosystem functions. The key challenge is to understand the resilience of these forests, and how this depends on forest attributes and environmental and anthropogenic drivers from local to continental spatial scales. We coordinate the secondary Neotropical forest network "2ndFOR". Furthermore, I participate in the transdisciplinary REFOREST-IT! project, which assesses the costs and benefits of different forest restoration methods across the tropics.