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Global rangelands and their role in food security Temuulen “Teki” Sankey Northern Arizona University Flagstaff, AZ
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Background I am a plant ecologist/dendrochronologist/RS I study rangeland use/land cover changes: – Intermountain USA: grassland-forest ecotones, aspen and pinyon-juniper woodlands – Great Basin: sagebrush shrublands – Sonoran Desert: desert invasive forbs – Central Asia: grassland steppe
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Cropland Grassland Shrubland Woodland Rangeland dynamics Time YearsDecades
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Western US Rangelands Climate change and land management-induced changes – Fire – Woody encroachment
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Western US Rangelands Wildfires are increasing in frequency and extent
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Idaho Rangelands Cheatgrass invasion – Fire cycle feedback – Sagebrush recovery
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Post-fire recovery in sagebrush 16 fires since 1937 SPOT image Sankey et al. 2008. Post-fire recovery of sagebrush communities: Assessment using SPOT5 and Very Large Scale Aerial Imagery. Rangeland Ecology and Management 61: 598-604
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Post-fire recovery in sagebrush Mountain big sagebrush Mean cover = 38% Time = 27 years Sankey et al. 2008. Post-fire recovery of sagebrush communities: Assessment using SPOT5 and Very Large Scale Aerial Imagery. Rangeland Ecology and Management 61: 598-604
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Sagebrush characterization - Lidar Classify sagebrush communities Shrub height Sankey, T. and P. Bond. 2010. Lidar-based classification of sagebrush community types. Rangeland Ecology and Management 64: 92-98
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Sagebrush Height - Lidar Sankey, T. and P. Bond. 2010. Lidar-based classification of sagebrush community types. Rangeland Ecology and Management 64: 92-98
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Sagebrush Height - Lidar Sankey, T. and P. Bond. 2010. Lidar-based classification of sagebrush community types. Rangeland Ecology and Management 64: 92-98
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Sagebrush Height - Lidar
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Western Rangelands: Juniper encroachment Juniper cover increase: 30-600% Encroachment leads to: – Understory vegetation loss – Soil erosion – Habitat loss – Fire hazard Control treatment – Prescribed fire – Cutting – Shredding
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Juniper encroachment Quantify encroachment rates and patterns Identify priority areas for control treatment
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Juniper encroachment Sankey et al. 2010. Characterizing western juniper expansion via a fusion of Landsat 5 Thematic Mapper and lidar data. Rangeland Ecology and Management 63: 514-523 Landsat Fusion Lidar
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Sankey et al. 2010. Characterizing western juniper expansion via a fusion of Landsat 5 Thematic Mapper and lidar data. Rangeland Ecology and Management 63: 514-523 Juniper encroachment
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Sankey, T. and M. Germino. 2008. Assessment of juniper encroachment with the use of satellite imagery and geospatial data. Rangeland Ecology and Management 61: 412-418
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Juniper encroachment Sankey et al. 2013. Lidar-derived carbon estimates in woody encroachment. Journal of Geophysical Research (In Press)
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Juniper encroachment Sankey et al. 2013. Lidar-derived carbon estimates in woody encroachment. Journal of Geophysical Research (In Press)
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Juniper encroachment
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Sankey et al. 2013. Lidar-derived carbon estimates in woody encroachment. Journal of Geophysical Research (In Press)
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Juniper encroachment Sankey et al. 2013. Lidar-derived carbon estimates in woody encroachment. Journal of Geophysical Research (In Press)
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Juniper encroachment Sankey et al. 2013. Lidar-derived carbon estimates in woody encroachment. Journal of Geophysical Research (In Press)
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Central Asian Rangelands Mongolia’s political changes Changes in herding practices Livestock numbers tripled
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Changes in herd distribution
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Effects on rangelands Landsat 5 TM 6 years: 1986, 1989,1990,…...shift… 2001, 2002, 2007 Collective vs post- collective Significant decrease
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Rangelands vs Croplands Many abandoned fields in former socialist countries Abandoned fields were used as rangelands New shift now
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Grassland Shrubland Woodland Cropland Rangeland dynamics Time YearsDecades
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Croplands vs Rangelands Time YearsDecades
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Crop Demand vs Supply Time YearsDecades Space Demand Supply?
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