Gardening with Native Plants - Michigan State University
Invasive Plants
1. Invasive Species –
The Problem
and
What We Can Do About It
Phyllis Muska
Native Plant Society of Texas – Kerrville Chapter
January 8, 2013
2. What is an invasive species?
Federal definition:
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
3. Invasives 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
4. Texas Invasive Plant and Pest 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
5. TIPPC
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
6. Problem invasives in other parts of 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
7. 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
8. 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
9. What makes a plant potentially 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
10. Why do people choose invasive plants?
Invasives can be pretty
Easily available and inexpensive
Unaware of problems they can cause
11. When is an ‘exotic’ not a 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
13. Advantages 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
23. Ligustrum (Japanese privet)
One of the top
terrestrial
invasives in
Central Texas
A top seller at
plant nursery
centers
Toxic leaves and
fruit
24. Alternatives to ligustrum
Often chosen as an evergreen screen
Alternatives include mountain laurel, evergreen sumac,
yaupon holly and cenizo
25. 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
26. Alternatives to nandina
Often chosen for
its reddish
foliage and red
berries
Possible
alternatives
include
possumhaw
holly and
flameleaf sumac
27. Vitex
Very pretty purple
flowers
A terrible invader
of ecosystems
along creeks and
rivers
Sometimes
marketed as ‘Texas
lilac’ – but it’s not
native!
28. Alternatives to vitex
Mexican bush
sage, Texas
mountain laurel,
redbud and
Mexican buckeye
are all good
alternatives with
showy blossoms
29. Chinaberry
Produce hundreds of
poisonous berries
Spread by birds
Problem in riparian
areas in particular
31. Chinese 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
32. Alternatives to Chinese tallow
For good fall color, consider:
– Flameleaf sumac
– Texas pistache
– Texas red oak
46. Bastard 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
48. Christ thorn
Native to
Mediterranean and Asia
Particularly invasive in
riparian areas
Forms thorny thicket
49. Hill 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
50. 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
51. 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
52. The 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!
53. Resources
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. Miller
http://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 /
54. Invaders – 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
55. 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!
56. Guess who’s coming to dinner?
Texas Monthly’s list of our five tastiest invasives
– Black Tiger Shrimp Penaeus monodon
57. Guess who’s coming to dinner?
Texas Monthly’s list of our five tastiest invasives
– Black Tiger Shrimp Penaeus monodon
– Bastard Cabbage Rapistrum rugosum
58. 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
59. 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
60. 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
61. Guess who’s coming to dinner?
Do your part to control
unwelcome populations–
eat more invasive species!
Notas do Editor
Edwards Plateau – increasing invasion by exotics Causes: Growing human population – humans are primary dispersal vector Development causes habitat destruction, and many invasives thrive in disturbed areas Edwards Plateau is most prone to flash flooding of all areas in the US – most seeds are dispersed more efficiently by water than by wind
Birds may not get the nutrients they need from non-native berries, for example. And some non-native plants such as Chinaberry can be fatal. Arundo donax, for example, causes erosion, damages bridges, alters channel morphology, increases costs for chemical and mechanical control along transportation corridors, and impedes law enforcement activities along international borders.
Note berries in photos – nandina and ligustrum
Fast-growing exotics can provide screening
disperses to great distances by wind, water, agricultural activities and animals Cannot tolerate repeated close mowing
Can be suppressed by timely mowing, burning, and herbicides
See Miller p.46 brought from Western Asia, Northern Africa and the Mediterranean in the 1800s as an ornamental plant. widely planted throughout the warmer areas of the US as an ornamental and for erosion control in the Southwest. tall, perennial grass that may grow to over 20 feet in height. fleshy, creeping rootstocks form compact masses from which tough, fibrous roots emerge that penetrate deeply into the soil. Reproduction primarily vegetative, through tuberous rhizomes which root and sprout readily. long, fibrous, interconnecting root mats choke riversides and stream channels, crowd out native plants, interfere with flood control, increase fire potential, and reduce habitat for wildlife. Large stands of giant reed change a territory from flood dependent to fire dependent habitat. It ignites easily and can create intense fires. Few herbivores browse the plant because the plant contains many toxic chemicals. Giant reed can float miles downstream where root and stem fragments may take root and initiate new infestations. New biological control approved recently by USDA: arundo scale
See Miller p.56
See Miller p.22 introduced from China, Japan and Korea colonizes by root sprouts and is spread by abundant bird- and other animal-dispersed seeds Few insects feed on it because chemicals in the leaves inhibit digestion. Ligustrum is widely believed to contribute to allergies and asthma
See Miller p.26 introduced from eastern Asia and India in the early 1800s colonizes by spreading underground root sprouts and by animal-dispersed seeds
See Miller p.8 introduced in the mid-1800s from the Himalayas and Asia widely planted as a traditional ornamental 98% germination rate Each berry can produce four seedlings
native to China and Japan Introduced into Georgia and S Carolina in 1700s Fallen tallow leaves release a cyanogenic compound capable of inhibiting growth of other plants Loss of grasslands: removes shelter and nesting habitat for the endangered Attwater Prairie Chicken and other species of concern Up to 100,000 seeds annually from each tree Propagates via seed and/or cuttings, stumps, roots See Miller p. 10
See Miller p. 2
See Miller p.4
See Miller p.38
Reported in Gillespie County – Schnerr Creek and Spring Creek
Widely raised for food in Asia, black tiger shrimp can grow up to a foot long and weigh up to a pound. Late last year they were found in Texas gulf waters according to Texas A&M scientists. Tiger shrimp, which make regular appearances on menus across the globe as as “giant tiger prawns,” can be cooked like any other crustaceans. Bastard cabbage , an invasive flowering weed native to the Eurasian steppe, threatens to choke out Texas’s bluebonnets. The taller-than-waist-high flowers prompt oohs and aahs, until the admirer learns the plant is up to no good. Bastard cabbage, which grow waist-high, rob wildflowers of “sun and soil nutrients.” A member of the mustard family, bastard cabbage is classified as a “noxious weed” by both the federal and state governments. How to prepare the plant: pick the young leaves and do a really simple saute with a little garlic, sea salt and lemon. Grass carp : Marinate deboned carp pieces in the refrigerator for at least an hour. Grill over a hot fire for carp fajitas. Nutria: Louisiana created a website, www.nutria.com , to encourage turning the large, rodents into fur coats and sausages. looks like a giant rat, but tastes like rabbit. Try nutria chili. Feral hogs cause an estimated $400 million in damage to property in Texas each year, Emerging as the ultimate invasive treat. Austin’s Dai Due holds a regular “ hog school ,” in which students hunt, butcher, and eat the hairy beasts. Feral hog is called wild boar when the meat hits your plate, so it lacks the branding problem that other invasives species face. Leaner than domestic hogs, they have a slightly nutty flavor that makes their meat more interesting than regular pork. See TPWD web site for recipes – Feral Hog Guisada, schnitzel, chili, tacos.