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Tuesday, April 10 • 10:00am - 10:15am
INVASIVE SPECIES: Dense Landsat Time Series Reveal Spatial and Temporal Patterns of Non-native Pine Invasion in Chile

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AUTHORS: Caroline A. Curtis*, Valerie J. Pasquarella, Bethany A. Bradley – University of Massachusetts

ABSTRACT: The spread of non-native conifers into areas naturally dominated by other vegetation types is a growing problem in South America. This process results in a landscape transformation as the conifers suppress growth and regeneration of native vegetation leading to altered water and nutrient availability and reduced biodiversity. In parts of Chile, pines are problematic due to widespread establishment of plantations and failure to control expanding populations. The large spatial extent and detectable spectral characteristics of non-native pines provide a unique opportunity to apply remotely sensed data to identify patterns of pine occurrences across the landscape. Previous research has identified the current and historical extent of non-native pines to quantify land cover changes. However, most studies have used a limited number of images to characterize change and covered a relatively small spatial area. This research uses a dense time series of Landsat images which allows us to capture the gradual invasion and dispersal process over more of the affected area. We used all available Landsat images for two scenes (Path 231/Row 092 and Path 232/Row 092) in southern Chile. For each scene, we created training data based on historical aerial photos from Google Earth. We then used time series models to quantify when land cover changes occurred and the Random Forest algorithm to classify images and create biennial maps showing changes in land cover. This method allowed us to use all of the high-quality pixels from each image, greatly improving our understanding of the spatial and temporal patterns of land cover change. In addition to creating risk maps for conifer invasion in Chile, this research also has implications for other ecosystems as it highlights the importance of using dense time series to monitor conifer spread.

Tuesday April 10, 2018 10:00am - 10:15am CDT
Spire Parlor