Get reliable rangeland science

Non-native species invasion is a recognized threat to grassland ecosystems. Invasive species can alter plant community composition, decrease biological diversity, change nutrient cycling and affect disturbance regimes. Old world bluestem (Bothriochloa ischaemum), not native to North America, can have negative impacts on native plant communities and is successful in establishing near-monoculture stands. Although common throughout central Texas, little is known about its full distribution. Our study aim was to examine the applicability of using remote sensing technology to detect stands of Old World Bluestem. We attempted to use phenological variation to distinguish the presence or absence of Old World Bluestem. The study examined sites located in the Southern High Plains ecoregion, which encompasses areas of northwest Texas and eastern New Mexico. This was conducted by examining sites representing a remnant shortgrass prairie system, dominated by blue grama (Bouteloua gracilis) and comparing those sites to areas of known Old World Bluestem occurrence. Landsat TM and ETM+ imagery was acquired for growing season months (roughly April through October) and NDVI values were calculated to determine start of season green up, peak greenness and fall senescence. Phenological and interannual variability between blue grama and Old World Bluestem sites might be useful for identifying possible invasion fronts.