Antarctic moss stress assessment based on chlorophyll content and leaf density retrieved from imaging spectroscopy data

• Main Authors: Malenovky, Zbynek, Turnbull, Johanna, Lucieer, Arko, Robinson, Sharon A
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Research Online 2015
• Subjects: Medicine and Health Sciences; Social and Behavioral Sciences; Antarctic; Antarc*; Schistidium antarctici
• Online Access: https://ro.uow.edu.au/smhpapers/3194; https://ro.uow.edu.au/cgi/viewcontent.cgi?article=4217&context=smhpapers

The health of several East Antarctic moss-beds is declining as liquid water availability is reduced due to recent environmental changes. Consequently, a noninvasive and spatially explicit method is needed to assess the vigour of mosses spread throughout rocky Antarctic landscapes. Here, we explore the possibility of using near-distance imaging spectroscopy for spatial assessment of moss-bed health. Turf chlorophyll a and b, water content and leaf density were selected as quantitative stress indicators. Reflectance of three dominant Antarctic mosses Bryum pseudotriquetrum, Ceratodon purpureus and Schistidium antarctici was measured during a drought-stress and recovery laboratory experiment and also with an imaging spectrometer outdoors on water-deficient (stressed) and well-watered (unstressed) moss test sites. The stress-indicating moss traits were derived from visible and near infrared turf reflectance using a nonlinear support vector regression. Laboratory estimates of chlorophyll content and leaf density were achieved with the lowest systematic/unsystematic root mean square errors of 38.0/235.2 nmol g−1 DW and 0.8/1.6 leaves mm−1, respectively. Subsequent combination of these indicators retrieved from field hyperspectral images produced small-scale maps indicating relative moss vigour. Once applied and validated on remotely sensed airborne spectral images, this methodology could provide quantitative maps suitable for long-term monitoring of Antarctic moss-bed health.