Quiet Invasion Update Invasive Plants of the Houston-Galveston Region
Lisa Gonzalez Research Scientist Houston Advanced Research Center Invasions in General
Invasive or exotic?
All exotics are not bad . Characteristics of Invasive Plant Species . High reproductive capability . Adaptability . Lack of ecological “checks and balances” . Alter surrounding environment
Pathways of Introduction
Landscaping and horticulture Aquarium/pet trade and pet owners Shipping & boating Agriculture & livestock Internet sales Live seafood markets Scientific research institutions, public aquaria, zoos, arboreta, wildlife preserves Biological control The Problem
Economic . Annually $120 billion in losses and control . Invasive plants: ~ $25 billion per year 5,000 introduced plant species in U.S. (Pimentel at al. 2005)
Social . Human health – vectors of disease . Quality of life
Ecological . Compete with native species . Alter species diversity & food webs . Introduce pathogens . Degrade water quality . Change fire regimes . Added stressor for regional habitats already under pressure Other Local Stressors
Wetland loss (1953-2005)
. >35K acres lost . Salt marsh: Loss slowed . Fresh water: Losses still occurring in NE part of region
Degraded water quality . Urban bacteria & HSC toxics
Some declining waterbird populations Armand Bayou Wallisville Lake Project Coastal Prairie Lake Conroe Invasive Species Regulation
Texas Department of Agriculture . Terrestrial plants . Maintains list of Texas noxious and invasive plants . List online at: Texas Admin Code (4 TAC §19.300)
Texas Parks & Wildlife Department . Aquatic plants & animals . Maintains list of prohibited animal species . Enforcement of aquatic and terrestrial invasive plant rules . List online at: http://www.tpwd.state.tx.us/huntwild/ wild/species/exotic/ Invasive Plant Profiles Chinese Tallow (Triadica sebifera)
. 1772: Benjamin Franklin sent seeds to Dr. Noble Wimberly Jones, Georgia Colony
. 1803: André Michaux noted spread in coastal forests
. Mature tree can produce up to100,000 seeds per year
. Seed dispersal by birds
. Drought and flood tolerant, variety of soils, pest resistant
. Crowds out natives; creates tallow forest
. Many parts of plant toxic; leaves alter soil chemistry
. Wildflower.org AlterNatives . Cercis canadensis (Eastern redbud) . Acer negundo (boxelder) . Ulmus crassifolia (cedar elm)
Established Prohibited Brazilian Pepper (Schinus terebinthifolius)
Early stage of invasion in Houston- Galveston
Native to Argentina, Paraguay and Brazil
Introduced ornamental in Florida in 1891; recognized as a nuisance in the 1950s
Aggressive shrub or small tree; shades out natives Bird- and mammal- dispersed seeds
May cause skin rashes (family Anacardiaceae)
. Wildflower.org AlterNatives . Morella cerifera (wax myrtle) . Ilex vomitoria (yaupon holly) . Prunus caroliniana (Carolina laurelcherry)
Established Prohibited Privet (Ligustrum sp.)
Native to China, Korea, Japan Brought to the US in the 1800s as an ornamental, popular landscaping plant Ligustrum sinense Bird- and mammal- dispersed seeds Chinese privet Shade and flood resistant Grows as a shrub to a small tree Colonizes shrub layer along forest edges and fencerows Forms dense thickets, dominates understory
Ligustrum lucidum Glossy privet . Wildflower.org AlterNatives . Morella cerifera (wax myrtle) . Ilex vomitoria (yaupon holly) . Prunus caroliniana (Carolina laurelcherry)
Established Species of Concern Ligustrum quihoui Waxyleaf privet Golden Bamboo (Phyllostachys aurea)
Native to China and Japan Alabama in 1800s as an ornamental; fence line buffer in residential and urban areas Above-ground jointed stem; spreads via runners Aggressive; spreads in all directions; up to 40 feet tall Dense thickets along roadsides; residential right of ways Displaces native vegetation and alters habitat Leaf litter alters invertebrate communities & food web Known to attract roaches in urban areas
. Wildflower.org AlterNatives . Morella cerifera (wax myrtle) . Ilex vomitoria (yaupon holly) . Panicum virgatum (switchgrass)
Established Species of Concern Japanese Honeysuckle (Lonicera japonica)
Native to Eastern Asia
Brought to the US in 1800s as an ornamental; planted for erosion control and deer forage
Evergreen to semi-evergreen
Reproduces via seeds and vegetatively; underground and above-ground runners
Seeds bird- and mammal- dispersed
Roadsides, forest edges, forest canopy gaps, fencerows, and abandoned fields or pastures
Smothers native shrubs and trees – blocks sunlight & twist around stems and trunks (cuts off flow of water) . Wildflower.org AlterNatives . Gelsemium sempervirens (evening trumpetflower) . Lonicera sempervirens (trumpet honeysuckle)
Established Species of Concern Asian Wisteria (Wisteria sp.)
Native to China and Japan
Brought to the US in 1800s as an ornamental; most infestations escaped landscape plantings Wisteria sinensis Seeds and pods toxic Chinese Wisteria
Forest edges and disturbed areas
Vine climbs host plants in a counter-clockwise spiral
Vines up to 70 feet long and 15 inches in girth
Can cover native shrubs and trees
. Wildflower.org AlterNatives . Wisteria frutescens (American wisteria) . Campsis radicans (trumpet creeper) . Lonicera sempervirens (trumpet honeysuckle) . Bignonia capreolata (crossvine)
Wisteria floribunda Established Species of Concern Japanese Wisteria Kudzu (Pueraria montana var. lobata)
Native to China and Japan
Introduced in the US in 1876 at Centennial Exposition in Philadelphia
Planted in 1930s as erosion control, forage, ornamental
Present in isolated locations in the Houston area and in E. Texas
Plants can produce 5,000-10,000 lbs biomass/acre
Shades out native vegetation
Vines grow to 90 feet long
. Wildflower.org AlterNatives . Wisteria frutescens (American wisteria) . Campsis radicans (trumpet creeper) . Lonicera sempervirens (trumpet honeysuckle) . Bignonia capreolata (crossvine)
Established Prohibited Grasses & Sedges
Deep-rooted sedge (Cyperus entrerianus) (Arundo donax) Giant reed . Native to South America . Native to India . Dark green, glossy leaves . Reaches 12 feet in height . Dense seed clusters . Flowers occur terminally in plume- . Sharp-angled, triangular stem like panicles . Purplish roots . Thrives in ditch banks, riparian or . Ditches, coastal prairies, wetlands, low floodplain areas flatwoods, fallow rice fields
Established Prohibited Established Species of Concern Hydrilla (Hydrilla verticillata)
Native to Southeast Asia Introduced in Florida in the 1960’s Popular aquarium plant
Grows in ponds, canals, rivers and ditches Found in Lake Conroe Forms dense horizontal mats Reproduces through seeds and budding Blocks water bodies, alters hydrology
Established Prohibited More Aquatic Plants Established
Prohibited Species of Concern Giant Salvinia (Salvinia molesta ) Elephant ear (Colocasia esculenta) . Native to South America . Native to South Asia and India . Mats float on the water surface . Popular horticulture plant . Streams, lakes, ponds, ditches . Wetland areas and banks of lakes . White, coarse hairs in egg-beater shape and bayous . Wildflower.org AlterNatives . Wildflower.org AlterNatives . Pontederia cordata (pickerelweed) . Nelumbo lutea (American lotus) . Sagittaria platyphylla (delta arrowhead) . Sagittaria platyphylla (delta arrowhead) . Nymphoides aquatica (Floating heart)
More Aquatic Plants Established Prohibited
Water hyacinth (Eichhornia crassipes) Alligator weed . Native to South America (Alternanthera philoxeroides)
. Bulb-like plants float on water . . Native to South America Showy lavender flowers . Shallow water, mats expand . Found in wetlands, ditches, lakes, across water surface rivers, bayous and canals . Stems succulent, pinkish-red; . Wildflower.org AlterNatives break easily . Pontederia cordata (pickerelweed) . Streams, lakes, ponds, ditches . Utricularia gibba (humped bladderwort) . Nymphaea mexicana (yellow waterlily) . N. odorata (American white waterlily)
Cactus Moth (Cactoblastis cactorum )
Other Invasive Animals
Pleco / armored catfish
IslandZebra applesnail mussel Stopping the Spread of Invasive Plants
Research and choose plants carefully
. IF YOU DON'T KNOW IT, DON'T GROW IT
Plant native plants when available
Watch local nursery inventories
Remove invasives from your property, gear, equipment, boats & trailers
. CLEAN, DRAIN & DRY
Never release or dispose of unwanted plants or animals into the local environment
Do not compost invasive plant material State-wide network of regional satellites
. 39 groups and 1,149 volunteers
. 42 volunteers in Houston-Galveston Invaders
Volunteers trained citizen scientist to identify and invasive plants
Provides invasive plant distribution data
Data used by the general public, scientists, and resource managers
http://www.texasinvasives.org Sources of Information
The Quiet Invasion: A Guide to Invasive Plants of the Galveston Bay Area www.galvbayinvasives.org
Texas Invasives www.texasinvasives.org
. Texas Invasive Plant and Pest Conference November 2011
Nonnative Invasive Plants of Southern Forests http://www.invasive.org/eastern/srs/
USDA PLANTS Database plants.usda.gov Thank You