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January 2013 presentation to Kerrville NPSOT
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Invasive Species – Invasive Species – The ProblemThe Problem
and and What We Can Do About ItWhat We Can Do About It
Phyllis MuskaPhyllis Muska
Native Plant Society of Texas – Kerrville Native Plant Society of Texas – Kerrville ChapterChapter
January 8, 2013January 8, 2013
An ‘invasive species’ is a species that is:– non-native (or alien) to the ecosystem
under consideration – aggressive, grows outside of desired
boundaries– outcompetes the natives– likely to cause harm to human health, the
economy, and/or the environment Can be plants, animals, and other organisms Primary means of invasive species
introduction: Human actions/activities
What is an invasive species?What is an invasive species?
Federal definition:
Invasives in TexasInvasives in Texas
More than 122 non-native species, including– 10 mammals – nutria, axis deer, feral hog– 4 birds – European starling, English sparrow– 7 fishes – grass carp– 11 insects – imported fire ant, German
cockroach– 11 mollusks and crustaceans – brown mussel,
brown garden snail– 12 aquatic plants – hydrilla, water hyacinth– 67 terrestrial plants
Texas Invasive Plant and Pest Texas Invasive Plant and Pest Council (TIPPC)Council (TIPPC)
Unified body to address the threat of invasive species in Texas
Stakeholders/participants:– State and federal agencies– Conservation organizations– Academia– Green industry – Public sector
TIPPCTIPPC
Focus for issues and concerns regarding exotic plants and pests
Exchange of information regarding all aspects of invasive pest and plant biology, distribution, control and management
Awareness and understanding regarding invasives and their control
Expert advice for various interests concerned with invasive pests and plants
An advisory council regarding funding, research, awareness, policy and management of invasive pests and plants
Problem invasives in other parts Problem invasives in other parts of USof US
Great Lakes – zebra mussels, sea lamprey Southeast – kudzu Hawaii – Indian Mongoose Everglades National Park – Giant Burmese
Python Over 2000 types of non-native creatures
imported legally into the US between 2000 and 2004
Why are invasives a problem?Why are invasives a problem?
High control costs – over $137 billion/year in US Loss of resources available to native species,
degrading diversity and wildlife habitat Destruction of special habitat of imperiled species Alter hydrological patterns, soil chemistry, moisture-
holding capacity, and erodibility Can change fire regimes, creating greater fire
hazard Some hybridize with native plant relatives, resulting
in unnatural changes to a plant's genetic makeup Can harbor plant pathogens that can affect both
native and non-native plants Fauna that depend on the native species for their
survival probably will not be able to adapt to the invader
How serious is the problem?How serious is the problem?
“On a global basis . . . the two great destroyers of biodiversity are, first, habitat destruction and second, invasion by exotic species.”
E. O. Wilson
What makes a plant potentially What makes a plant potentially invasive?invasive?
Well adapted to the climate and soils of an area High reproductive success Grows and spreads rapidly Favorable environmental conditions, lack of
natural predators, competitors and diseases
Why do people choose invasive Why do people choose invasive plants?plants?
Invasives can be pretty Easily available and inexpensive Unaware of problems they can cause
When is an ‘exotic’ not a When is an ‘exotic’ not a problem?problem?
Many do not cause harm to the economy, the environment, or our health
Most ‘introduced’ species do not survive Only about 15% of those that do survive
go on to become a problem Well-behaved introduced species include
crepe myrtle, herbs such as Russian sage, Mexican oregano, and rosemary
Some invasives may take Some invasives may take years to become problematicyears to become problematic
Advantages of native plantsAdvantages of native plants
Native plant, animal and insect species work together to keep a balance
Maintain diversity, avoid monocultures Well-adapted to extremes of weather,
climate
Invasive GrassesInvasive Grasses
JohnsongrassJohnsongrass
Considered one of the ten most noxious weeds in the world
Competes with crops
King Ranch bluestemKing Ranch bluestem
BermudagrassBermudagrass
““Improved” grassesImproved” grasses
Klein grass, Dallisgrass, rescuegrass, rattail smutgrass, and other introduced species planted for livestock pasture
Giant caneGiant caneArundo donaxArundo donax
BambooBamboo
Dense stands that exclude other plants from creating an understory
Monocultures like this destroy ecosystems
Alternatives to giant cane and Alternatives to giant cane and bamboobamboo
Texas pistache is an attractive screen with good fall color
Invasive Trees and ShrubsInvasive Trees and Shrubs
Ligustrum (Japanese privet)Ligustrum (Japanese privet)
One of the top terrestrial invasives in Central Texas
A top seller at plant nursery centers
Toxic leaves and fruit
Alternatives to ligustrumAlternatives to ligustrum
Often chosen as an evergreen screen Alternatives include mountain laurel, evergreen
sumac, yaupon holly and cenizo
Nandina (Sacred bamboo)Nandina (Sacred bamboo)
Mistaken for a native because it is so pervasive in our natural areas
Colonizes via spreading underground roots
Seed dispersed by animals
Alternatives to nandinaAlternatives to nandina
Often chosen for its reddish foliage and red berries
Possible alternatives include possumhaw holly and flameleaf sumac
VitexVitex
Very pretty purple flowers
A terrible invader of ecosystems along creeks and rivers
Sometimes marketed as ‘Texas lilac’ – but it’s not native!
Alternatives to vitexAlternatives to vitex
Mexican bush sage, Texas mountain laurel, redbud and Mexican buckeye are all good alternatives with showy blossoms
ChinaberryChinaberry
Produce hundreds of poisonous berries
Spread by birds Problem in
riparian areas in particular
Alternatives to ChinaberryAlternatives to Chinaberry
Western soapberry has beautiful fall color and berries very similar to Chinaberry
Chinese TallowChinese Tallow
Tops list of invasive plants in the Southeastern United States
Spread by birds and water Changes grassland into
tallow forests Now comprises about 40%
of the Houston tree canopy
Allowed to grow and reproduce because of its pretty fall color
Alternatives to Chinese tallowAlternatives to Chinese tallow
For good fall color, consider:– Flameleaf sumac– Texas pistache– Texas red oak
AilanthusAilanthus(Tree of Heaven) (Tree of Heaven)
Chinese pistacheChinese pistache
Mimosa (Silk tree)Mimosa (Silk tree)
Invasive VinesInvasive Vines
Japanese honeysuckleJapanese honeysuckle
Covers and smothers other plants
Chris Evans, Illinois Wildlife Action Plan, Bugwood.org
Alternatives to Japanese Alternatives to Japanese honeysucklehoneysuckle
Carolina jessamine
Coral honeysuckle
Cross vine Texas wisteria
English ivyEnglish ivy
Covers and smothers other plants
Randy Cyr, Greentree, Bugwood.org
James H. Miller, USDA Forest Service, Bugwood.org
Non-native thistlesNon-native thistles
Musk thistleMusk thistle
Bull thistleBull thistle
Photographer: Steve Dewey,Source: Utah State University, Bugwood.org
Sow thistleSow thistle
Malta starthistleMalta starthistle
Photographer: Joseph M. DiTomaso, University of California - DavisSource: Bugwood.org
New on the sceneNew on the scene
Bastard cabbageBastard cabbage
Bastard cabbage – quickly choking out many of our spring wildflowers
Forms a large rosette that prevents other forbs from germinating
Pull up by roots in spring, before it flowers
Brazilian vervainBrazilian vervain
Displaces native vegetation Particularly invasive in riparian areas
Christ thornChrist thorn
Native to Mediterranean and Asia
Particularly invasive in riparian areas
Forms thorny thicket
Hill Country Dirty DozenHill Country Dirty Dozen Glossy privet – Ligustrum lucidum Chinese tallow – Triadica sebifera Tree of heaven – Ailanthus altissima Giant reed – Arundo donax Johnsongrass – Sorghum halepense King Ranch bluestem – Bothriochloa ischaemum
var. sangarica Chinaberry – Melia azedarach Japanese honeysuckle – Lonicera japonica Heavenly bamboo – Nandina domestica Golden raintree – Koelreuteria paniculata Brazilian vervain – Verbena brasiliensis Bastard cabbage – Rapistrum rugosum
What can you do?What can you do?
Choose native plants Replace invasive plants on your property Be alert to accidental transport of invasives
via shoes and clothing, boats, cars Spread the word about invasive plants Patronize nurseries specializing in natives Ask your local nursery to stock native
varieties Share plants, but make sure you know
what you’re giving or receiving
What Can You Do? cont’d.What Can You Do? cont’d.
Check the contents on seed mixes for invasives
Use ‘certified weed free’ soils and mulches Dispose of invasive plants carefully – bag or
burn For potentially invasive plants that you can’t
part with, harvest and dispose of fruits and seeds before they can spread
Join a volunteer network to help identify and remove invasive plants from natural areas – see http://www.texasinvasives.org for details on Wildflower Center initiative
The goalThe goal
Preserve and restore natural areas that support the beautiful and diverse plants and wildlife native to Central Texas
Prevention: $1 dollar of prevention is worth $100,000 of the cure
Control a little now or deal with a lot later!
ResourcesResources
Lady Bird Johnson Wildflower Center – Texas Invasives project http://www.texasinvasives.org/
The Global Invasive Species Initiative http://www.issg.org/
Nonnative Invasive Plants of Southern Forests by James H. Millerhttp://www.invasive.org/eastern/srs/
Weeds Gone Wild http://www.nps.gov/plants/alien/index.htm
Nature Conservancy’s Global Invasive Species Team: http://www.invasive.org/gist/ /
Invaders – since 2005Invaders – since 2005
www.texasinvasives.org Program developed at Lady Bird Johnson
Wildflower Center Over 1400 citizen scientists trained 40+ satellites across the state Over 17,000 invasive plants documented
and mapped
Want to get involved?Want to get involved?
Join the ‘Texas Invaders’ Go to http://texasinvasives.org Choose ‘Citizen Science’, then ‘Become a Citizen Scientist’ Follow instructions for Voyager online
training Choose ‘Hill Country’ satellite Begin reporting!
Guess who’s coming to dinner?
Texas Monthly’s list of our five tastiest invasives– Black Tiger Shrimp Penaeus monodon
Guess who’s coming to dinner?
Texas Monthly’s list of our five tastiest invasives– Black Tiger Shrimp Penaeus monodon– Bastard Cabbage Rapistrum rugosum
Guess who’s coming to dinner?
Texas Monthly’s list of our five tastiest invasives– Black Tiger Shrimp Penaeus monodon– Bastard Cabbage Rapistrum rugosum– Asian Carp (grass carp) Ctenopharyngodon
idella
Guess who’s coming to dinner?
Texas Monthly’s list of our five tastiest invasives– Black Tiger Shrimp Penaeus monodon– Bastard Cabbage Rapistrum rugosum– Asian Carp (grass carp) Ctenopharyngodon
idella – Nutria Myocastor coypus
Guess who’s coming to dinner?
Texas Monthly’s list of our five tastiest invasives– Black Tiger Shrimp Penaeus monodon– Bastard Cabbage Rapistrum rugosum– Asian Carp (grass carp) Ctenopharyngodon
idella – Nutria Myocastor coypus– Feral pig Sus scrofa
Guess who’s coming to dinner?
Do your part to control unwelcome populations– eat more invasive species!