I and others contributed to an interesting case study on buffelgrass in the greater Tucson area. Check out this link and see whats going on.
https://usbr.maps.arcgis.com/apps/MapSeries/index.html?appid=3627aad031d44e33acda00a46e882147
https://usbr.maps.arcgis.com/apps/MapSeries/index.html?appid=3627aad031d44e33acda00a46e882147