A Survey of the Invasive Aquatic and Riparian Plants of the Low Rio Grande

Hydrilla (Hydrilla verticillata) has exhibited extensive range expansion along the Rio Grande since its first discovery in early 1990 and is now found in areas far removed from the original infestation (Brownsville, TX). Hydrilla, a nonindigenous aquatic plant species, has been implicated in restricted water delivery, inaccurate water accounting, and an overall breakdown of system maintenance. In addition, the presence of hydrilla has had a decided impact on native flora by the formation of extensive monocultures in many areas. In 2001 and 2003, surveys were conducted starting below Amistad Reservoir to immediately below Falcon Reservoir to assess the distribution and expansion of the hydrilla infestations and document the presence of other invasive aquatic and riparian plant species. Several small infestations of hydrilla, as well as several other invasive aquatic and riparian plant species, were observed during the 2003 survey. Small sections of the river were surveyed. A total of six introduced plant species were observed, including hydrilla, Eurasian watermilfoil, parrotfeather, elephant-ear, giant cane, and salt cedar.
The original document contains color images.