Insect herbivory dampens Subarctic birch forest C sink response to warming

• Published in: Nature Communications
• Main Authors: Silfver, Tarja, Heiskanen, Lauri, Aurela, Mika, Myller, Kristiina, Karhu, Kristiina, Meyer, Nele, Tuovinen, Juha-Pekka, Oksanen, Elina, Rousi, Matti, Mikola, Juha
• Other Authors: Academy of Finland, Koneen Säätiö
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2020
• Subjects: General Physics and Astronomy; General Biochemistry, Genetics and Molecular Biology; General Chemistry; Subarctic
• Online Access: http://dx.doi.org/10.1038/s41467-020-16404-4; http://www.nature.com/articles/s41467-020-16404-4.pdf; http://www.nature.com/articles/s41467-020-16404-4

Abstract Climate warming is anticipated to make high latitude ecosystems stronger C sinks through increasing plant production. This effect might, however, be dampened by insect herbivores whose damage to plants at their background, non-outbreak densities may more than double under climate warming. Here, using an open-air warming experiment among Subarctic birch forest field layer vegetation, supplemented with birch plantlets, we show that a 2.3 °C air and 1.2 °C soil temperature increase can advance the growing season by 1–4 days, enhance soil N availability, leaf chlorophyll concentrations and plant growth up to 400%, 160% and 50% respectively, and lead up to 122% greater ecosystem CO 2 uptake potential. However, comparable positive effects are also found when insect herbivory is reduced, and the effect of warming on C sink potential is intensified under reduced herbivory. Our results confirm the expected warming-induced increase in high latitude plant growth and CO 2 uptake, but also reveal that herbivorous insects may significantly dampen the strengthening of the CO 2 sink under climate warming.