May 2017
Articles on Invasive Species Now Published in IEEE Earthzine

As mentioned in previous iWires, the online magazine IEEE Earthzine is focusing on invasive species for a few months. As guest editor, I am pleased to announce that several articles have now been published:

Expect more articles very soon, including mine on the Invaders of Texas citizen science program!

Colorado toadflax biocontrol
Release of Dalmatian toadflax weevils. Credit: Dan Bean, Colorado Department of Agriculture

Earthzine logo image

TPWD Launches Its 2017 Aquatic Invasives Campaign

With the busy summer boating season getting underway, the Texas Parks and Wildlife Department and a coalition of partners are ramping up efforts against aquatic invasive species like zebra mussels (Dreissena polymorpha) and giant salvinia (Salvinia molesta). Their major public awareness campaign is calling for boaters to protect the lakes they love by taking the time to clean, drain and dry their boat and gear before traveling from lake to lake.

This year’s campaign includes a new look, with updated advertising that was informed by learning from a survey of 27,000 registered boaters and from focus groups with boaters in Dallas and Houston. The new messaging aims to connect boaters’ love of the lake experience with their sense of responsibility to care for the lakes – and to provide easy directions on how to do that. Boaters will see and hear this information on billboards, gas station pump toppers, online, social media, radio ads, print ads and at the boat ramps around any lake that is currently infested with zebra mussels or giant salvinia.

While the emphasis is on encouraging people to do the right thing voluntarily, it is illegal to possess or transport any exotic aquatic plant or animal listed as harmful or potentially harmful, with violations carrying fines of $25-$500. Boaters are also required to drain all water from their vessels and onboard receptacles before driving on public roadways. Information on these laws is on the TPWD website.

Help us stop the spread of invasive species by sharing this short video about how to properly clean, drain and dry your boat, trailer and gear. You can also order a number of free outreach materials on the website.

The coalition of partners supporting this year’s campaign includes the North Texas Municipal Water District; Tarrant Regional Water District; City of Dallas Water Utilities Department; Trinity River Authority; Lower Colorado River Authority; San Jacinto River Authority; Sabine River Authority; Brazos River Authority; Coastal Water Authority; Guadalupe-Blanco River Authority; Upper Trinity Regional Water District; Water Oriented Recreation District of Comal County; and the Lady Bird Johnson Wildflower Center.


Zebra mussel

Impact of Removing Invasive Plants on Natives Is Variable

In many, if not most cases in Ecology, the answer to a question is "It depends". In another example of this, two studies show different results of removing invasive plants, one positive and one negative. Directly comparing these two studies is of course not possible, but they do illustrate how different approaches can lead to different conclusions that are yet valid.

A new study featured in the journal Invasive Plant Science and Management shows the impact of weedy invaders can linger for years after their removal. (See also The researchers removed Japanese stiltgrass (Microstegium vimineum), one of the worst invasive species in the Eastern U.S., from their study site in Virginia and studied the effects on the ecosystem. While some soil nutrients began to shift towards an uninvaded state, they never fully recovered. In addition, vegetation became less like the original native plant community. Many of the plants that emerged after Japanese stiltgrass was removed were themselves weedy species, creating a new wave of control challenges. Moreover, the nature and persistence of the changes depended on whether the populations of stiltgrass were new or established. From our perspective, these results also illustrate an important point we make to our Invaders of Texas participants and Satellites, and to other groups to whom we give presentations about invasive plant management: removal is not sufficient. Replanting natives is typically going to be an integral and necessary component of successfully restoring areas with invasive plants, especially if they are well-established.

In the other study (see also, performed in the mountains of the Seychelles, researched discovered that physically removing all of the invasive plants in a given area allows native plants and pollinators to regain at least some of their former vitality. The pollinator community changed, and the remaining native plants set more fruit as a result. Thus, in this case, removal of invasives had a positive effect, even though the invasives were not replaced with native plants.

Japanese Stiltgrass Removal

Credit: Seychelles News Agency,CC-BY

Our Changing World Opens the Door for a New Wave of Biological Invasions

An international team of scientists has identified how our rapidly changing world will bring new types of invaders, often from very unexpected places. Globalization of the Arctic, emergence of invasive microbial pathogens, advances in genomic modification technology, and changing agricultural practices were judged to be among the 14 most significant issues potentially affecting how invasive species are studied and managed over the next two decades. For example, "The cultivation and distribution of 'growth enhancing' microbes could cause some crop plants or plant species residing near agricultural fields to become invasive pests" says Prof. Daniel Simberloff." Read more at, and the research article in Trends in Ecology and Evolution.

earth-invasives connection
Credit: Tends in Ecology and Evolution, Volume 32, Issue 6, p464–474, June 2017

AgriLife Extension Community Fire Ant Control Program a Template for Success

For more than a decade, Texas A&M AgriLife Extension Service integrated pest management program specialist Wizzie Brown has been engaged in a community-wide battle against one of the state’s most persistent pests – the fire ant. Brown and residents of the Wood Glen community in Round Rock, north of Austin, have collaborated in a neighborhood fire ant program to control the proliferation of fire ants, eliminate their unsightly mounds and keep them from biting area residents. Brown said similar community-wide fire ant control efforts have also taken place in Bexar and Harris counties in collaboration with the integrated pest management specialists in the AgriLife Extension offices in those two counties. Read more at Texas A&M AgriLife Extension.


Fire Ant Control Program

Invasive Spotlight:
Glossy Privet
(Ligustrum lucidum)

Glossy privet has the potential to replace mid-canopy trees in forests and completely dominate an area of forest or forest fragments if not controlled. Still sold in nurseries, it often displaces native species in regenerating communities and if left undisturbed, may eventually dominate an area of forest.

Glossy privet is a fast-growing evergreen shrub or tree approximately 25ft (8m) to 40ft (14m) in height with a 25ft (8m) to 35ft (12m) spread. It has a dense canopy of bending branches composed of glossy green leaves that have narrow, translucent margins. Leaves are 3"–6" (7.5cm-15cm) long, dark green, with a paler green undersurface; have 6-8 more or less prominent veins on each side of the midrib; tend to be creased at the midrib; usually possess an acuminate tip; and can be bent without breaking easily. Flowers are produced in large clusters and are small, cream-colored and strongly scented. After pollination by insects, fruits ripen into bunches of small, oblong, 1 cm long, purplish-black berries. Both leaves and fruit are poisonous to humans.

Learn more about glossy privet at
glossy privet
Credit: James H. Miller, USDA Forest Service,

glossy privet invading forest
Credit: James H. Miller, USDA Forest Service,

More News

Agrilife Extension Effort Monitors Sugarcane Aphid Seasonal Movement
A minuscule pest few Texas farmers had never heard of three years ago has quickly gained notoriety as the most important insect pest of grain and forage sorghum in Texas, according to AgriLife Extension entomologist Steve Byrnes. As in past years, the sugarcane aphid (Melanaphis sacchariis) expected to move into Central Texas and eventually the Texas High Plains, potentially infesting all of Texas’ sorghum-producing regions by late summer. Read more at

APHIS Establishes a Mexican Fruit Fly Quarantine in the Ygnacio Area of Zapata County
Effective April 9, the Animal and Plant Health Inspection Service (APHIS) established a Mexican fruit fly (Anastrepha ludens or Mexfly) quarantine in a residential area of San Ygnacio, Zapata County, Texas. APHIS is applying safeguarding measures and restrictions on the interstate movement or entry into foreign trade of regulated articles from this area. The establishment of this quarantine area is reflected on their website.

New Invasive Clam in the US
A new non-native clam was recently found in the Illinois River near the city of Marseilles, Ill., about 80 miles west of Lake Michigan -- a strange entry point for an invasive Asian clam. The scientists who found it have no idea how it got there. But the discovery -- along with genetic tests that confirm its uniqueness -- means that a new species or 'form' of invasive clam has made its official debut in North America. Read more at

Resistance to Herbivory Varies Among Tamarix Populations
Growing evidence suggests that the hybridization of Tamarix may provide variation in traits that could promote local adaptation. Read more at

Modeling Zebra Mussels' Infiltration of North American Rivers
The invasion of nonnative species has widespread and detrimental effects on local and global ecosystems. These intruders often spread and multiply prolifically, displace native species, alter the intended interactions between flora and fauna, and damage the environment and economy. Scientists now present a continuous-discrete hybrid population model that describes the invasive dynamics of zebra mussels (Dreissena polymorpha) in North American rivers. The model predicts that zebra mussels cannot persist naturally if river flow and temperature prevent them from spreading upstream. Read more at

Researchers to Test Moth Pest Genetically Engineered to Self-Destruct
Researchers in a New York cabbage patch are planning the first release on American soil of insects genetically engineered to die before they can reproduce. Read more at

Scientist Identify Key Locations for Spread of Pin-Tailed Whydahs
A new study analyzes the case of a brood parasitic bird, the pin-tailed whydah (Vidua macroura) and its recent spread into the Americas. Read more at

Significant Increase of Invasive Seaweed Changing New England Sea Habitat
Researchers looked at seaweed populations over the last 30 years in the Southwestern Gulf of Maine and found the once predominant kelp beds are declining and more invasive species have taken their place, altering the seascape and marine food chain. Read more at

Invasive Rabbitfish Spread Other Invasive Species Via Gut
For some time, unicellular benthic organisms (ones that live on the sea floor) from the Indo-Pacific have been spreading in the Mediterranean. An international team of scientists has now found evidence that a possible path of invasion has been in the gut of fish. Read more at

Changes in European Freshwater Fish Species Communities Since 1840 Include Non-native Species
Over time, humans have contributed to the loss of native species and have introduced non-native species throughout Europe. A new analysis shows how European freshwater fish have changed profoundly since 1840. At the continental scale, the contemporary fauna holds net 11 more species today as exotic species introduction (26 species) exceeded native species loss (15 species). But the biggest change was made by European species introduced from one area in Europe to another (77 species), often with fatal results. Read more at

Intensifying Postfire Weather and Biological Invasion Drive Species Loss in a Mediterranean-Type Biodiversity Hotspot
Researchers studying the Fynbos of South Africa (a Mediterranean-type ecosystem recognized as a "hotspot" for biodiversity) for over 40 years have found that postfire summer weather events have become increasingly severe, and that combined with legacy effects of historical woody alien plant densities 30 years after clearing, this change in severity has led to a significant decline in biodiversity. For more, see the PNAS research article.

"Yellow Crazy Ant" Workers Lay Eggs as a Food Source
Scientists have revealed that for workers in the invasive species of 'yellow crazy ant', Anoplolepis gracilipes, worker-laid eggs provide a valuable energy source for selected colony members. These revelations came as a surprise to the researchers, but also gave them hints for controlling infestations. "We can now develop a strategy to combat this invasive species," continues co-author Chow-Yang Lee. For example, incorporating a low concentration of the hormonal analogue 'JHA' as an active ingredient in bait used against yellow crazy ants may produce the desired growth-limiting effect. Learn more at


If you would like to highlight a successful invasive species project or nominate a special person to be highlighted in an upcoming iWire, please send the details to

Sentinel Pest Network and Invaders of Texas Species Workshops

Invaders of Texas workshops train volunteers to become citizen scientists to detect and report invasive species. Workshops, which are free, include information on the Sentinel Pest Network, which serves to increase the awareness and early detection of the Emerald Ash Borer, Cactus Moth, Asian Longhorned Beetle, and other pests of regulatory significance.

Workshops are tailored to meet the interests of your volunteer group, and supplementary session examples include an introduction to the TX Invaders mobile application and the Eradicator Calculator, a feature on designed to help organize and track volunteer-based eradication efforts.

Upcoming Workshops:

Saturday, July 29, 2017
Location: Jesse H. Jones Park & Nature Center (Humble, TX)
Contact: Rose Belzung Holmes

For more information or to register to attend a free workshop, please visit the Workshop Page.