Watershed Protection Plan - Lower Rio Grande Valley Development ...

STATE OF THE WATERSHED
native plant species. Some of the most common
invasive plant species found in the Lower Rio Grande
Valley area are provided in Table 5.
Table 5.
Predominant Invasive Plant Species Known
to Occur in Terrestrial and Aquatic Habitats
Associated with the Arroyo Colorado in
Hidalgo, Cameron and Willacy Counties
Invasive giant reeds on unstable Arroyo Colorado banks
areas of turbulence that would facilitate re-aeration of
the water column (APAI 2006).
Invasive plant species, both native and introduced,
occur in terrestrial and aquatic habitats associated
with the Arroyo Colorado and the Lower Rio Grande
Valley. Invasive species often have a negative impact
on native plant and wildlife populations. Common
reed (Phragmites australis) and giant reed (Arundo
donax), which occur along the banks of the Arroyo
Colorado, spread so quickly that they form expansive
monospecifi c stands; this decreases plant diversity
and excludes species that have a higher value to
wildlife over large areas. Exotic plants of various
species exclude other plant species from growing near
or beneath them either directly, through allelopathic
processes (suppression of growth through the release
of toxins) as is the case with tamarisk (Tamarix sp.) and
buffelgrass (Pennisetum ciliare), or indirectly, through
competition for water and/or light, as with Brazilian
pepper (Schinus terebinthifolius). Other invasive
species, such as guinea grass (Panicum maximum),
reduce the vigor and density of desirable native species
around them through resource competition. Invasive
plant species, particularly exotics, generally provide
lower quality habitat (including food, cover, and nesting
sites) for native wildlife species than do non-aggressive
Plant Species
UPLAND GRASSES
Bermudagrass
(Cynodon dactylon)
Buffelgrass (Pennisetum ciliare)
Guinea Grass (Panicum maximum)
King Ranch bluestem
(Bothriochloa ischaemum)
UPLAND TREES/SHRUBS
Black mimosa (Mimosa pigra)
Black willow (Salix nigra)
Brazilian pepper
(Schinus terebinthifolius)
Chinaberry (Melia azedarach)
Chinese tallow
(Sapium sebiferum)
Jara (Baccharis salicifolia)
Retama (Parkinsonia aculeata)
Roosevelt willow
(Baccharis neglecta)
Salt cedar (Tamarix sp.)
Tree morning glory
(Ipomoea carnea)
Tree tobacco (Nicotiana glauca)
TRANSITIONAL GRASSES
Common reed
(Phragmites australis)
Giant cane (Arundo donax)
WETLAND AND AQUATIC PLANTS
Cattail (Typha domingensis)
Hydrilla (Hydrilla verticillata)
Water hyacinth (Eichornia crassipes)
Native (N) or
Introduced (I)
to Watershed
I
I
I
I
N
N
I
I
I
N
N
N
I
I
I
N
I
N
I
I
Arroyo Colorado Watershed Protection Plan 36 January 2007