Since the industrial revolution, the concentration of CO2 in the atmosphere has increased significantly, primarily from the burning of fossil fuels, but this has been offset by strong land and ocean carbon (C) sinks, with about a third of anthropogenic CO2 emissions absorbed by Earth’s terrestrial ecosystems. Critically, the ability of this C sink to maintain current uptake rates is unclear and may change due to feedbacks from higher CO2 (e.g. warmer temperatures, drier conditions or altered precipitation patterns, higher disturbance frequency). Moreover, the process models we use to project the responses of terrestrial ecosystems to a changing environment often lack the detailed spatial and temporal information on key plant traits and responses to environmental conditions needed for adequate forecasting future climate conditions. This is particularly true for biomes with only sparse observational data availability such as the Arctic and tropics, highlighting the need for the capacity to remotely monitor vegetation responses to change.
Here we highlight our use of leaf, near surface, and airborne reflectance spectroscopy instrumentation and data to characterize the variation in plant albedo, traits and physiological functioning across space and time as well as capture responses to stress and disturbance.
Results/Conclusions
This research spans from the Arctic to the tropics and explored a range of plant species including grasses, forbs, shrubs, managed croplands, and forests measured in natural and controlled environments. We show that leaf-level spectroscopy can capture a broad range of leaf traits from a range of environments using simple algorithms that can be applied globally. Moreover, we highlight the ability of leaf spectra to capture temporal changes in leaf function and traits in response to seasonal changes and stress (drought), including traits related to photosynthetic capacity. Near-surface observations allow us to capture changes in plant canopy reflectance and albedo across space and through time in Arctic ecosystems. We also show how airborne observations can be used to characterize landscape-scale patterns in vegetation responses and recovery from stress and disturbance. Overall, this work highlights the capacity for reflectance spectroscopy to characterize spatial and temporal variation in vegetation functioning in a changing environment.