Thermal remote sensing for plant ecology from leaf to globe

Abstract

Surface temperatures are mechanistically linked to vegetation biophysical and physiological processes. Although remote sensing in the thermal infrared (TIR) domain can offer novel insights into the impacts of changing surface temperatures on vegetation, the transformative potential of remote sensing for plant ecology has not yet been realized. Remotely sensed surface temperatures can be used to derive stomatal behaviour and identify stressful environmental conditions in near‐real time. Plant species, traits and structural characteristics can be evaluated with high spectral resolution TIR emissivity. Beyond canopy scales, thermal remote sensing can enhance the inferences obtained from manipulative experiments and empirical evidence, providing unique insight into shifts in species ranges and phenology with changing climate conditions. Scaling leaf traits, canopy structure and regional patterns require an integrated understanding of both process and technology. Theory linking surface temperatures to vegetation dynamics is summarized from an energy balance perspective. We outline scaling considerations including the impacts of morphology on leaf energy balance, canopy structure influences on convective heat exchange and potential confounding impacts of non‐vegetated surfaces. Synthesis. We introduce a unifying framework to link leaf to globe through thermal remote sensing. Recent and emerging advances in sensors, data availability and analytics, together with synergies between TIR remote sensing and other data sources, present a timely opportunity for ecologists to advance our understanding of plant physiology, ecology and biogeography with thermal remote sensing.

Does plant ecosystem thermoregulation occur? An extratropical assessment at different spatial and temporal scales

“…Whether plants can thermoregulate themselves to adapt to future warming climates has received increasing attention over recent years, but remains debated with views from no to moderate thermoregulation capabilities (Farella et al ., 2022; Still et al ., 2022). To reconcile these seemingly contrasting views, we assessed the extent to which the ‘limited homeothermy’ hypothesis holds across various plant ecosystems.…”

“…These unavoidable uncertainties are results of the inherent bias in reanalysis systems and the effect of sensor noises and unstable atmospheric conditions in satellite‐based retrievals (Wan, 2014; Parker, 2016; Muñoz‐Sabater et al ., 2021). Additionally, due to the coarse resolution, T c from satellite or EC cannot eliminate interference from nonleaf information, such as branches and trunks (Farella et al ., 2022). Furthermore, both EC‐ and satellite‐derived T c mainly reflect the dynamics of the upper canopies and rarely reflect the T c of middle canopies or understory (Still et al ., 2021).…”

“…This is also called the ‘limited homeothermy’ hypothesis. Previously, this hypothesis was primarily tested using limited leaf‐scale data in experimental conditions, such as glasshouse or gas change chambers, or on well‐watered crop species (Still et al ., 2019; Farella et al ., 2022). However, whether such ‘limited homeothermic’ behaviors can be extended beyond the scale of individual leaves and whether it varies among different plant functional types (PFTs) around the world remains unknown.…”

Hyperspectral Remote Sensing for Phenotyping the Physiological Drought Response of Common and Tepary Bean

“…Proximal remote sensing offers a powerful tool for high-throughput phenotyping of plant physiology [ 9 – 11 ]. Remote sensing techniques such as thermal-based [ 12 , 13 ], lidar-based [ 14 , 15 ], and optical-based [ 16 ] methods have shown promise for assessing plant water status. Sensors can be deployed on various platforms that include handheld instruments, ground-based vehicles, towers, unoccupied aerial vehicles, piloted aircraft, and satellites, all with different spatial and temporal trade-offs [ 4 ].…”

Heat dissipation from photosynthesis contributes to maize thermoregulation under suboptimal temperature conditions

“…T L can be used to evaluate plant thermoregulation and acclimation, presenting great potential for remote sensing thermal applications (Farella et al, 2022). T L depends on several interrelated factors.…”