Tamarisk, Woody Vegetation and Arthropod Community Dynamics and a Retrospective Tamarisk Establishment Study along the Dolores River below McPhee Dam, Southwest Colorado

Riparian environments in their natural state (unregulated rivers) are maintained by natural flow regimes that native species have evolved to over thousands of years. It has been hypothesized by researchers that the alteration of the natural flow regime is a principal driver in the shift of riparian plant community composition and structure to favor non-native plant establishment by species such as tamarisk and Russian olive. It is important to understand what environmental factors are associated with tamarisk and other woody vegetation, as well as what historical conditions allowed tamarisk invasion in the first place. Our research from November 2009 to December 2011 was conducted on the Dolores River in southwestern Colorado, a regulated river which is the focus of an extensive tamarisk removal project spearheaded by the Dolores River Restoration Partnership. This final report is divided into four main research projects with summary points at the end of each section: a) tamarisk and woody vegetation community dynamics; b) groundwater hydrology and associated environmental drivers; c) dendroecology tamarisk recruitment; and, d) riparian arthropod community dynamics in tamarisk dominated and woody shrub habitats.