Effects of Elevated Atmospheric CO2 Concentration on Insect Herbivory and Nutrient Fluxes in a Mature Temperate Forest

Insect herbivory is one of the most important ecological processes affecting plant–soil feedbacks and overall forest ecosystem health. In this study, we assess how elevated carbon dioxide (eCO2) impacts (i) leaf level insect (ii) stand-level herbivore-mediated transfer (C) nitrogen (N) from canopy to ground in a natural mature oak temperate community central England at Birmingham Institute Forest Research Free Air CO2 Enrichment (BIFoR FACE) site. Recently abscised leaves were collected every two weeks through growing season August December 2017–2019, with identification four dominant species: Quercus robur (pedunculate oak), Acer pseudoplatanus (sycamore), Crataegus monogyna (common hawthorn) Corylus avellana (hazel). The selected scanned visually analyzed quantify area loss folivory monthly. Additionally, C N fluxes tree species Q. was calculated these leaf-level estimates, total foliar production contents. This study finds that BIFoR FACE has not changed significantly across first 3 years eCO2 treatment when assessed all species, although detected significant changes under for individual years. Despite lack any strong response, estimated transferred via substantially higher eCO2, mainly because there ~50% increase eCO2. result cautions against concluding much either presence or absence responses environmental effect, their actual effects are filtered so many (usually unmeasured) factors.