313
13.2.1 Close-Range EO Approaches
13.2.1.1 Spectral Laboratory
The reactions of plants to stress phenomena depend on the plant species (Müller
2009; Teodoro et al. 2016). Teodoro et al. (2016) analyzed the different strategies of
Brazilian tree species like Campomanesia pubescens (Myrtaceae), Eremanthus
seidellii, and Lessingianthus warmingianus (Asteraceae) to cope with drought
stress. The results showed different reactions and trade-offs to maintain plant functioning under drought stress conditions. Moreover, the ability of different tree species to adapt to climate change is still not well understood (Beck and Müller 2007).
Reactions of woody plants to stress factors such as drought can often only be
observed years later in the form of biochemical, physiological, or geometric changes
to woody plant traits (Buddenbaum et al. 2015b). Therefore, specific in-situ investigations need to be conducted on the stress reactions of different taxonomic plants to
determine the spectral responses to different drivers.
With the help of close-range laboratory spectroscopy (see Fig. 13.2a, b), extensive long-term stress monitoring can be carried out that takes into account entire
vegetation periods as well as investigations over several years. Scenarios specifically targeted at investigating different stress factors such as stress from drought,
ozone levels, fungal infestations, pesticide deposits, or temperature increases or
decreases are conducted under comparable settings and environmental conditions,
enabling good inputs for models and eliminating confounding factors. In addition to
imaging and nonimaging spectrometer measurements, a broad range of parameters
for vegetation traits, soil, and climate can be measured with in-situ approaches.
Brosinsky et al. (2013) investigated the spectral response from the impacts of flooding on the physiological stress reactions of ash trees Fraxinus excelsior L. over a
3-month period, whereas Buddenbaum et al. (2015b) modeled the photosynthesis
rate of young European beech trees under drought stress using hyperspectral visible
infrared and hyperspectral thermal sensors. They created high spatial resolution
(cm) maps of photosynthetic activity using the photochemical reflectance index
(PRI), fluorescence, and temperature. Other approaches have derived the different
phenology indicators of barley with imaging hyperspectral RS over its entire development period (Lausch et al. 2015b).
13.2.1.2 Plant Phenomics Facilities
One of the most important challenges in plant biology and vegetation stress physiology is the qualitative, quantitative, and spectroscopic recording of plant species
phenotypes to gain a better understanding of interactions between the genotype and
the phenotype. The genotype of a plant species comprises its genetic information,
while the phenotype represents the physiological, morphological, anatomical, and
development characteristics as well as interactions with the environment, resource
13 A Range of Earth Observation Techniques for Assessing Plant Diversity
13.2.1 Close-Range EO Approaches
13.2.1.1 Spectral Laboratory
The reactions of plants to stress phenomena depend on the plant species (Müller
2009; Teodoro et al. 2016). Teodoro et al. (2016) analyzed the different strategies of
Brazilian tree species like Campomanesia pubescens (Myrtaceae), Eremanthus
seidellii, and Lessingianthus warmingianus (Asteraceae) to cope with drought
stress. The results showed different reactions and trade-offs to maintain plant functioning under drought stress conditions. Moreover, the ability of different tree species to adapt to climate change is still not well understood (Beck and Müller 2007).
Reactions of woody plants to stress factors such as drought can often only be
observed years later in the form of biochemical, physiological, or geometric changes
to woody plant traits (Buddenbaum et al. 2015b). Therefore, specific in-situ investigations need to be conducted on the stress reactions of different taxonomic plants to
determine the spectral responses to different drivers.
With the help of close-range laboratory spectroscopy (see Fig. 13.2a, b), extensive long-term stress monitoring can be carried out that takes into account entire
vegetation periods as well as investigations over several years. Scenarios specifically targeted at investigating different stress factors such as stress from drought,
ozone levels, fungal infestations, pesticide deposits, or temperature increases or
decreases are conducted under comparable settings and environmental conditions,
enabling good inputs for models and eliminating confounding factors. In addition to
imaging and nonimaging spectrometer measurements, a broad range of parameters
for vegetation traits, soil, and climate can be measured with in-situ approaches.
Brosinsky et al. (2013) investigated the spectral response from the impacts of flooding on the physiological stress reactions of ash trees Fraxinus excelsior L. over a
3-month period, whereas Buddenbaum et al. (2015b) modeled the photosynthesis
rate of young European beech trees under drought stress using hyperspectral visible
infrared and hyperspectral thermal sensors. They created high spatial resolution
(cm) maps of photosynthetic activity using the photochemical reflectance index
(PRI), fluorescence, and temperature. Other approaches have derived the different
phenology indicators of barley with imaging hyperspectral RS over its entire development period (Lausch et al. 2015b).
13.2.1.2 Plant Phenomics Facilities
One of the most important challenges in plant biology and vegetation stress physiology is the qualitative, quantitative, and spectroscopic recording of plant species
phenotypes to gain a better understanding of interactions between the genotype and
the phenotype. The genotype of a plant species comprises its genetic information,
while the phenotype represents the physiological, morphological, anatomical, and
development characteristics as well as interactions with the environment, resource
13 A Range of Earth Observation Techniques for Assessing Plant Diversity