Santa Cruz River Riparian Vegetation Mapping Project Santa Cruz County, Arizona Santa Cruz County, Arizona October 15, 2008 Prepared for Santa Cruz County October 15, 2008 Prepared by: Sonoran Institute 7650 E. Broadway Blvd. Suite 203 Tucson, Arizona 85710 University of Arizona Remote Sensing Center Office of Arid Lands Studies University of Arizona 1955 E. 6th Street Tucson, Arizona 85719 Table of Contents Acknowledgements ................................................................................................................................................................ 8 Executive Summary ................................................................................................................................................................ 9 Introduction ............................................................................................................................................................................. 11 Project Purpose ................................................................................................................................................................. 11 Background and Need ..................................................................................................................................................... 11 Methods ..................................................................................................................................................................................... 14 Definitions ........................................................................................................................................................................... 14 Survey/Mapping ............................................................................................................................................................... 14 Quickbird imagery ....................................................................................................................................................... 15 Orthorectification and Pansharpening ............................................................................................................... 15 Formation Map.............................................................................................................................................................. 15 Plant List ............................................................................................................................................................................... 18 Alliance Assignment ........................................................................................................................................................ 18 Alliance Verification ........................................................................................................................................................ 18 Groundwater Basin Assignment ................................................................................................................................. 19 Conservation Prioritization .......................................................................................................................................... 20 Results ........................................................................................................................................................................................ 22 Formation and Alliance Mapping ............................................................................................................................... 22 Alliance Verification ........................................................................................................................................................ 23 Conservation Prioritization .......................................................................................................................................... 35 Conclusions and Recommendations .............................................................................................................................. 40 References ................................................................................................................................................................................ 41 Appendix A: Alliance Descriptions ................................................................................................................................. 43 Forest Alliances ............................................................................................................................................................ 43 Cottonwood-Goodding’s willow Forest Alliance ...................................................................................... 43 - 3 - Cottonwood-[Velvet mesquite-Elderberry] Forest Alliance ................................................................ 43 Tamarisk Forest Alliance .................................................................................................................................... 44 Velvet mesquite – [Elderberry – Netleaf hackberry] Forest Alliance .............................................. 44 Velvet mesquite – Catclaw acacia Forest Alliance .................................................................................... 45 Velvet mesquite Forest Alliance ...................................................................................................................... 45 Woodland Alliances .................................................................................................................................................... 47 Cottonwood – Goodding’s willow – Tamarisk Woodland Alliance ................................................... 47 Cottonwood – Goodding’s willow Woodland Alliance ........................................................................... 47 Cottonwood – Velvet Mesquite Woodland Alliance ................................................................................ 48 Cottonwood Woodland Alliance ...................................................................................................................... 48 Velvet mesquite – Catclaw acacia Woodland Alliance ............................................................................ 49 Velvet mesquite – Elderberry Woodland Alliance ................................................................................... 49 Velvet mesquite – Netleaf hackberry Woodland Alliance ..................................................................... 50 Velvet mesquite Woodland Alliance .............................................................................................................. 50 Wooded Shrubland Alliances .................................................................................................................................. 52 Velvet mesquite / Catclaw acacia Wooded Shrubland Alliance ......................................................... 52 Velvet mesquite / Velvet mesquite Wooded Shrubland Alliance ...................................................... 52 Shrubland Alliances .................................................................................................................................................... 53 Catclaw acacia – Whitethorn acacia – Catclaw mimosa Shrubland Alliance ................................. 53 Hymenoclea Shrubland Alliance ...................................................................................................................... 53 Seepwillow Shrubland Alliance ....................................................................................................................... 53 Tamarisk Shrubland Alliance ............................................................................................................................ 54 Velvet mesquite – Catclaw acacia Shrubland Alliance............................................................................ 54 Velvet Mesquite Shrubland Alliance .............................................................................................................. 55 Tree Savanna Alliances .............................................................................................................................................. 56 Cottonwood/Amaranth Tree Savanna Alliance ........................................................................................ 56 - 4 - Cottonwood/Native grass Tree Savanna Alliance .................................................................................... 56 Elderberry/Amaranth Tree Savanna Alliance ........................................................................................... 57 Tamarisk/Amaranth Tree Savanna Alliance .............................................................................................. 57 Velvet Mesquite/Amaranth Tree Savanna Alliance ................................................................................ 57 Velvet Mesquite/Native Grass Tree Savanna Alliance ........................................................................... 58 Velvet Mesquite/Tumbleweed Tree Savanna Alliance .......................................................................... 58 Shrub Savanna Alliances ........................................................................................................................................... 59 Baccharis/Amaranth Shrub Savanna Alliance ........................................................................................... 59 Baccharis/Grass Shrub Savanna Alliance ...................................................................................................