7
ESTIMATING GRASSLAND
CHLOROPHYLL CONTENT FROM
LEAF TO LANDSCAPE LEVEL:
BRIDGING THE GAP IN SPATIAL
SCALES
YUHONG HE
7.1 INTRODUCTION
Approximately one-fifth of Earth’s land surface is covered by grasslands, both natural
and disturbed (He and Mui, 2010). Grasslands worldwide have experienced significant degradation and extinction due to urbanization, overgrazing, land use conversion
(i.e. crop and pastoral lands), climate change, and mining. As an example, the
Canadian tallgrass prairies once covered approximately 1000 km
2 of southern
Ontario. However, less than 1% of its historic range in southern Ontario remains.
It is thus imperative that research is done in the way of conservation, management,
and restoration efforts for the endangered grassland prairie ecosystems.
Quantifying vegetation biochemical properties could advance our understanding
of vegetation physiological processes and provide insight into detection and monitoring of vegetation conditions under the context of environmental stressors (Evans,
1989; Yoder and Pettigrew-Crosby, 1995; Wu et al., 2008). One of the primary
vegetation biochemical properties, chlorophyll (Chl a + b), is responsible for photosynthesis and has been used to characterize plant physiological status and health
under stress (i.e., Blackburn, 1998; Zarco-Tejada et al., 2002), investigate plant
126
Scale Issues in Remote Sensing, First Edition. Edited by Qihao Weng.
Ó 2014 John Wiley & Sons, Inc. Published 2014 by John Wiley & Sons, Inc.
ESTIMATING GRASSLAND
CHLOROPHYLL CONTENT FROM
LEAF TO LANDSCAPE LEVEL:
BRIDGING THE GAP IN SPATIAL
SCALES
YUHONG HE
7.1 INTRODUCTION
Approximately one-fifth of Earth’s land surface is covered by grasslands, both natural
and disturbed (He and Mui, 2010). Grasslands worldwide have experienced significant degradation and extinction due to urbanization, overgrazing, land use conversion
(i.e. crop and pastoral lands), climate change, and mining. As an example, the
Canadian tallgrass prairies once covered approximately 1000 km
2 of southern
Ontario. However, less than 1% of its historic range in southern Ontario remains.
It is thus imperative that research is done in the way of conservation, management,
and restoration efforts for the endangered grassland prairie ecosystems.
Quantifying vegetation biochemical properties could advance our understanding
of vegetation physiological processes and provide insight into detection and monitoring of vegetation conditions under the context of environmental stressors (Evans,
1989; Yoder and Pettigrew-Crosby, 1995; Wu et al., 2008). One of the primary
vegetation biochemical properties, chlorophyll (Chl a + b), is responsible for photosynthesis and has been used to characterize plant physiological status and health
under stress (i.e., Blackburn, 1998; Zarco-Tejada et al., 2002), investigate plant
126
Scale Issues in Remote Sensing, First Edition. Edited by Qihao Weng.
Ó 2014 John Wiley & Sons, Inc. Published 2014 by John Wiley & Sons, Inc.