ABSTRACT
Vegetation diversity is multidimensional and tremendously complex in space and time. To understand the status, stress, disturbances, and resource limitations of vegetation diversity and consequently vegetation health and its resilience in ecosystems, there are two principal methodologies: (i) the in situ approach adopted by taxonomists and (ii) the remote sensing approach. Here, we describe both approaches and focus on the applicability, the advantages, the unique features, and limitations of hyperspectral remote sensing (HRS) technology for monitoring the status, stress, and shifts in four diversity characteristics: phylogenetic, taxonomic, structural, and functional diversity.
HRS is currently the only approach available for monitoring the status, adaptations, shifts, stress, and disturbances of all four characteristics of vegetation diversity. However, it is subject to certain limitations that will be discussed in this chapter in detail.
HRS is a crucial technique for recording spectral-based traits and trait variations, but compared to the morphological species concept (MSC) adopted by taxonomists, not all traits and trait variations can be recorded using HRS. For this reason, we refer to the recording and monitoring of traits and trait variations using HRS techniques as “spectral traits” (ST), to the changes of spectral traits as “spectral trait variations” (STV) and lastly to this remote sensing approach as the “remote sensing-spectral traits/spectral traits variation-concept” (RS-ST/STV-C).
So far, HRS is the only remote sensing technology enabling assertions about the status and shifts of phylogenetic vegetation diversity to be made. A better discrimination among different plant taxa, communities, and landscapes is possible with HRS techniques compared to broadband RS approaches, due to the discrimination of numerous traits and trait variations in finer detail. Furthermore, the status, shifts, and stress in structural as well as functional vegetation diversity can also be recorded well using HRS, which is also the most successful technique for characterizing a number of ecosystem functions in detail.
HRS data collected from different platforms (close-range, airborne, spaceborne) has the capability to record traits and their variations on different levels of vegetation organization. It is able to do this through time (from the short term to the long term) and space (from local to global) and is, therefore, an indispensable technique in understanding the complexity and disturbances of vegetation diversity and its characteristics.
