Integrating measures of grassland function using Remote Sensing

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Grasslands provide vital global ecosystem services, are sensitive to disturbance and invasion, and are prone to rapid functional collapse. Grasslands worldwide have been degraded in recent decades due to intense human activity and climate change, and this degradation not only threatens ecosystems, but negatively affects ecosystem services. The pressures from degradation emphasize the need to understand, evaluate, and monitor grassland ecosystems. For decades, studies have used remote sensing tools to determine solitary measures of grassland growth and productivity, such as cover, biomass, leaf area index, canopy height, cover, structural heterogeneity, and burn and grazing effects. While this approach has advanced our understanding of how to monitor specific elements of the grassland community in isolation, a barrier to continued progress in assessing ecosystem health and its services is to integrate different elements and approaches holistically. Therefore, the long-term objective of my program is to contribute to achieving optimal and high-quality ecosystem services while maintaining sustainable grassland ecosystems. A comprehensive grassland assessment is hindered by uncertainties of understanding the expansion of unwanted species and the methods to detect and effectively assess their impacts using remote sensing and geospatial methods. Thus, I propose to focus on woody plant encroachment (WPE) and integrate this within grassland ecosystem health assessments for this proposal. WPE is a natural ecosystem process but has become a threat to grassland ecosystem health because of the effects of climate change and lack of a clear understanding of the WPE mechanisms especially in Canadian prairies, a location where WPE was not an issue in the past. There are two major challenges to understand WPE in grasslands using remote sensing and spatial techniques. First, woody plant cover is highly heterogeneous leading to mixed pixels that include various types of cover. This is because grasslands appear in various WPE stages. Second, a woody plant has typical healthy vegetation spectral features that are hard to separate from healthy productive grass species. Therefore, my five-year objectives are to 1) develop effective approaches to assess WPE in grasslands using remote sensing; 2) understand the drivers of WPE in grasslands using remote sensing, geographic information science, and spatial analytical techniques; and 3) integrate WPE into grassland ecosystem health assessment and facilitate WPE modelling. My research is devoted to understanding Canadian grassland ecosystems and I strive to keep them healthy ecologically and economically. The expected results will reveal the driving factors of WPE scholarly in the Canadian prairies, provide potential solutions for the issues, and gain new knowledge in maintaining grassland ecosystem services. This program will also provide a great opportunity for training high quality personnel.