New research published in the journal Science, led by Lauren Waller at the Bio-Protection Research Centre, Lincoln University, and in collaboration with John Hunt, Nina Koele and Kate Orwin from Manaaki Whenua, shows that exotic plants can temporarily accelerate carbon loss from soils through their interactions with invertebrate herbivores and soil biota.
The paper is the culmination of 4 years of large-scale experiments, between 2016 and 2019, in which scientists from six international research organisations and universities, including Manaaki Whenua, AgResearch and Scion, created 160 experimental plant communities, each with one of 20 different 8-species combinations of native and exotic plants.
The researchers quantified how each plant community or ‘mesocosm’ interacted with insect herbivores and soil microorganisms, and measured indicators of carbon cycling. They conclude that novel biological interactions between invertebrates, soil biota and exotic plant species are a more important driver of ecosystem transformation than was previously thought.
The study also provides important insights for decision-making in ecosystem restoration. Fast-growing exotic plants may be suitable for plantings when the goal is to sequester carbon above ground, but may have more variable effects below ground than native plants.