Watch List: non-native species in Texas potentially
ranked as F1
Many of the
non-native species in Texas are known from relatively few populations. Among these are a significant number that
have been recently recorded for the state and that are known to be both
invasive and ecologically destructive in other regions of the United States or
other parts of the world. These
features characterize the species included on the “Watch List” –– the ones with
high potential to rapidly become destructive in Texas. A number of additional F3 species,
especially the woody ones, and some of those ranked as F4 (“status unknown”)
probably belong on the Watch List.
The Watch List
account perhaps is the most significant part of the overview of Texas
non-native native plants provided here.
The F1 species and many of the F2s are well-known invaders and already
so widespread that it is unlikely that they can be eradicated or even
controlled except by sustained efforts on local levels. In a summary of efforts toward control of
Giant Salvinia in Texas, it’s noted that “The only positive
control discovered after 10 years of trial and error is the containment and
removal of all plants immediately after detection” (Howard Elder, 2009, TIPPC
Conference Abstract).
Research toward
the possibility of biological control will be ongoing. Further, there probably is little hope even
of eradicating many of the Watch List species –– a number of the woody species are widely cultivated, providing
abundant seed sources close to natural areas, and it is unlikely that plants
will be removed from the cultivated landscape.
Some measure of control might be gained by limiting further
planting.
From among the
Watch List species, a subset is indicated here as a “Super Watch List” (as marked with *asterisks below) ––
those species that perhaps can be removed from the Texas landscape before they
become impossible to control. Close attention should go to these. All of the F2 aquatics are included because
of their potential for rapid dispersal and growth.
*Solanum
viarum -- attempt to eradicate (but becoming
locally abundant)
from
F2-WOODY:
*Hypericum perforatum -- attempt to eradicate
*Pueraria montana var. lobata
-- attempt to eradicate
Pyrus calleryana --
widely cultivated,
probably here to stay and increase
from F3-WOODY:
*Ardisia crenata
-- attempt to eradicate
*Casuarina
equisetifolia -- attempt to eradicate
*Cinnamomum camphora
-- attempt to eradicate (but commonly cultivated)
*Cortaderia
selloana -- attempt to eradicate (but commonly cultivated)
*Elaeagnus
angustifolia -- attempt to eradicate
*Leucaena
leucocephala -- attempt to eradicate
*Lonicera maackii
-- attempt to eradicate (but becoming
locally abundant)
*Macfadyena unguis-cati -- attempt to eradicate
Photinia serratifolia -- widely cultivated, probably here to stay and increase
* Pyracantha koidzumii -- attempt to eradicate
Schinus molle --
widely cultivated, probably here to stay and increase
*Schinus
terebinthifolius -- attempt to eradicate
Ulmus parvifolia -- widely cultivated, probably here to stay and increase
from F2-HERBACEOUS:
Carduus tenuiflorus -- already abundant, at
least locally, probably here to stay and increase
Cirsium vulgare --
already abundant, at least locally, probably here to stay and increase
*Clematis terniflora --
attempt to eradicate (but becoming locally abundant)
*Gibasis pellucida --
attempt to eradicate
*Lespedeza cuneata
-- attempt to eradicate (but becoming locally
abundant)
Lolium (Festuca) arundinaceum --
already abundant, at least locally, probably here to stay and increase
Perilla frutescens -- already abundant, at
least locally, probably here to stay and increase
Polygonum arenastrum --
already abundant, at least locally, probably here to stay and increase
Polygonum persicaria -- already abundant, at least
locally, probably here to stay and increase
Stachys floridana -- already abundant, at least locally,
probably here to stay and increase
Torilis arvensis -- already abundant, at least locally, probably here to stay and increase
Verbena brasiliensis -- already abundant, at least locally, probably here to stay and increase
from F3-HERBACEOUS:
*Carduus
acanthoides -- attempt to eradicate
*Cayratia japonica
-- attempt to eradicate
*Cryptostegia grandiflora -- attempt to eradicate
*Cuscuta japonica -- attempt to eradicate
*Elymus
repens -- attempt to eradicate
*Imperata cylindrica --
attempt to eradicate
*Lespedeza
bicolor -- attempt to eradicate
*Lotus corniculatus -- attempt to eradicate
*Lythrum salicaria -- attempt to eradicate
*Microstegium vimineum --
attempt to eradicate
from F4-HERBACEOUS:
*Acroptilon
repens -- attempt to eradicate
*Dioscorea
bulbifera -- attempt to eradicate
from F2-AQUATIC:
*Ceratopteris thalictroides --
attempt to control and eradicate
*Colocasia esculenta --
attempt to control and eradicate
*Cryptocoryne beckettii --
attempt to control and eradicate
*Egeria densa --
attempt to control and eradicate
*Hydrocleys nymphoides -- attempt to control and
eradicate
*Hygrophila polysperma --
attempt to control and eradicate (but becoming locally abundant)
*Landoltia punctata --
attempt to control and eradicate
*Limnophila sessiliflora --
attempt to control and eradicate
*Ludwigia grandiflora subsp. grandiflora
-- attempt to control and eradicate
*Nomaphila stricta --
attempt to control and eradicate
*Nymphoides indica --
attempt to control and eradicate
*Nymphoides peltata --
attempt to control and eradicate
*Ottelia alismoides --
attempt to control and eradicate
*Potamogeton crispus --
attempt to control and eradicate
*Salvinia minima --
attempt to control and eradicate
*Xanthosoma sagittifolium --
attempt to control and eradicate
Potential and expanding new
arrivals with global warming
in south and coastal Texas:
(fide Tom Patterson, South Texas College, Rio Grande City)
Caesalpina bonduc
Canavalia rosea
Cassytha filiformis
Conocarpus erectus
Laguncularia racemosa
Rhizophora mangle
Scaveola plumieri
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Last update: 18 Oct 2009