Aditya Ganesh: Douglas-fir as a Global Experiment in Invasion Ecology

You originally come from India and are now pursuing your PhD in Prague. What were the most surprising aspects of the city or the academic environment when you first arrived?

Prague has pleasantly surprised me in many ways. Its gothic and baroque architecture is a sight to behold, and large portions of the city center are pedestrian friendly. The connectivity and efficiency of public transport are also excellent. I also enjoy the green spaces within the city, such as Letná and Stromovka parks. The academic environment at FISC and CZU has been very nurturing, with a collaborative team that enables cutting-edge research and provides access to global perspectives on invasion ecology.

What inspired you to pursue research in invasion ecology?

Working as an ecologist in south India, I witnessed firsthand the impacts that plant species such as Lantana camara, Netulma juliflora, and Senna spectabilis had on forest, grassland, and agroecosystems. These species were spreading rapidly and taking over the landscape at the expense of native species. I soon learned that they were not native to India and were considered ‘invasive’. This sparked my interest in invasion ecology and in understanding what enables certain non-native species to establish, spread, and transform ecosystems.

Your research focuses on Douglas-fir. What makes this species particularly interesting from an ecological or invasion perspective?

Douglas-fir is a fascinating species, both in its native and non-native ranges. It’s planted worldwide for forestry outside its native range in North America, effectively creating a global experiment in invasion ecology. This provides an opportunity to study not only how Douglas-fir establishes and spreads in novel environments, but also how its associated pests and pathogens respond to these introductions and influence invasion dynamics.

You study insect herbivores associated with Douglas-fir in different parts of the world. How do these interactions differ across regions?

Douglas-fir is planted widely outside its native range under different ecological contexts. In some regions, it experiences reduced herbivory due to the absence of co-evolved insects, consistent with the enemy release hypothesis. In other regions, specialized herbivores such as the Douglas-fir seed chalcid have been accidentally introduced, causing substantial damage. Local generalist herbivores may also incorporate Douglas-fir into their diets, creating novel interactions that did not occur in its native range. As a result, interactions between Douglas-fir and its herbivores vary substantially across regions.

Part of your research involves using CT scanning to study seeds inside cones. Could you briefly describe how this works in your research?

The work focuses on detecting infestation by the Douglas-fir seed chalcid inside Douglas-fir cones. Traditional approaches require dissection of cones and seeds, which is time-consuming and prevents repeated analysis. CT scanning allows multiple cones to be scanned simultaneously, revealing intact seeds, empty seeds, and seeds containing developing chalcid larvae that consume the seed from the inside

Non-native forest plantations can pose ecological risks. In your view, what are some challenges posed by these plantations?

Non-native plantations can be economically valuable, but they carry ecological risks. Trees planted outside their native range may spread beyond plantation boundaries, establishing in natural habitats and altering habitat structure and species composition, which threatens native biodiversity. They can also facilitate the introduction and spread of novel pests and pathogens, with potential spillover effects on native trees.

What questions about Douglas-fir invasions or plant–insect interactions would you most like to answer in the future?

I’m interested in pursuing synthesis work that integrates data across regions to better understand the factors shaping both the current and future suitability of Douglas-fir for plantation forestry worldwide. I would like to address how climatic conditions, local biotic interactions, and invasion dynamics influence its performance outside its native range. In the context of invasions, a key question is what determines whether Douglas-fir transitions from a managed plantation species to a potentially invasive one in certain regions but not others. From a host–herbivore interaction perspective, I’m interested in how associations with pests and pathogens affect the establishment, spread, and long-term viability of Douglas-fir.