March 2019
Texas A&M AgriLife Extension Service Offers Invasive Species Workshop on April 17 in Sonora

The Texas A&M AgriLife Extension Service offices in Sutton and Crockett counties will present a Texas Invasive Species Workshop on April 17 at the Sutton County Civic Center, 1700 N. Crockett Ave., Sonora. Topics include the impacts and control of feral hogs; invasive plants; axis deer; and pesticide laws and regulations.

Onsite registration is at 8 a.m., and the program will begin at 8:30 a.m. Texas Department of Agriculture continuing education units are available.

The cost of the workshop is $15; after April 12, it is $25. The fee covers program materials, refreshments and lunch.

For more details, follow this link, or contact Pascual Hernandez, 325-387-3101,

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feral hog and piglets

Credit: minds-eye/Flickr--Creative Commons

Non-Native Species Are Primary Cause of Recent Global Extinctions

You probably know that non-native species have caused native species to go extinct. But how large is that impact? Now we know. According to a new study, non-native species are the main driver of recent extinctions of both animals and plants. Scientists found that since 1500, alien species have been solely responsible for 126 extinctions, 13 percent of the total number studied. Learn more at

accelerating rates of global extnction 2

Credit: https://www.climateemergencyinstitute .com/ecosystems_and_species.html

University of Texas Invasive Species Program Receives Financial Support

Destructive and costly fire ants, crazy ants, moth larvae and invasive grasses can wreak havoc on Texas ecosystems, but biologists at The University of Texas at Austin are bringing the fight to them. With the help of a $6 million continuing grant from the Lee and Ramona Bass Foundation, researchers in the Texas Invasive Species Program will seek new, sustainable approaches to counter exotic pests that threaten Texas.

During the next six years, scientists based at the Brackenridge Field Laboratory (BFL) will identify ways to combat five invasive species that have settled in Texas without the natural predators, competitors and diseases that kept them in check in their native environments. The five species are red imported fire ants (Solenopsis invicta), tawny crazy ants (Nylanderia fulva) and exotic cactus moths (Cactoblastis cactorum), all native to South America, and guinea grass (Megathyrsus infestus) and buffel grass (Cenchrus ciliaris) from Africa.

Consider sending a letter of thanks to the Bass Foundation!

Read this news release for more information.

UTInvasives-Bass Foundatn

Dr. Dino Martins (center), director of Mpala Research Center, shows Dr. Rob Plowes (left) and Dr. Larry Gilbert (right) some buffelgrass—an invasive in Texas—in its Kenyan home range. Credit: UT-College of Natural Sciences

Brazilian Peppertree Demonstrates Its Resilience

The Texas Gulf Region Cooperative Weed Management Area is working through its partners to improve native coastal prairie on Mustang Island around Port Aransas by removing Brazilian peppertree (Schinus terebinthifolius). The plant has proven to be resilient, making them very difficult to remove. As the photos to the right illustrate, branches and stems that were cut and remained on the ground sprouted roots, and furthermore, the seed bank under many trees is tremendous, so that even if the tree is killed, there can be an ample supply of replacements. Clearly, as with many invasive plants, removing Brazilian peppertrees requires tireless and costly vigilance and retreatments.

Brazilian Peppertree cut branch sprouting roots

Credit: Daniel McLendon, American Conservation Experience

Brazilian Peppertree seedlings carpeting the ground

Credit: Daniel McLendon, American Conservation Experience

As the World Warms, How Do We Decide When a Plant is Native?

Suppose many years ago your father planted a tree that doesn't grow naturally in your area, but is native further south, say 200 miles. The tree does very well, growing large and beautiful. It flowers and sets seed for years, but none of its offspring survive in the surrounding neighborhood and natural area – until recently. Individuals of the same species are now popping up with more frequency. The climate has warmed over the intervening years, allowing the plants to survive. Further south, the range has expanded northward to a limited degree, also due to climate warming.

Now consider: by planting and nurturing the tree in your yard, have you unintentionally introduced an invasive species, or have you simply aided in the species' natural range expansion?

This is the question that botanists, conservation biologists, and ecologists are wrestling with. Climate change is causing plant and animal species to change their distribution, but plants are predicted to have a harder time responding to climate change than mobile animals. Can homeowners assist plants in their northward moves by planting them in their yards further north than the plants' present distribution? Should they? Are these types of species "non-native"? Or are they simply current examples of the changes in plant distributions that have occurred over and over as glaciers expanded and retreated? It's clear that these species are different from invasive species that are not native to North America, because those invasives typically do not have the population controlling mechanisms they evolved with in their native area. The species your family planted, on the other hand, does. But how should we view your species?

For a more detailed discussion of this fascinating topic, and for links to scientific journal articles, read this article from YaleEnvironment360.

This website provides a wealth of information and links on assisted migration/colonization/dispersal and the debate surrounding it.


PlantHardiness changes 1990 to 2006

A map of the United States’ various temperature zones, created by the U.S. Department of Agriculture and used by farmers and gardeners to determine which plants can thrive where. From 1990 to 2006, several of the zones — based on average extreme minimum temperature, ranging from -30 degrees F (deep purple) to 40 degrees F (light pink) — shifted northward in response to climate change. Arbor Day Foundation.

assisted migration explanation

Assisted migration can occur as assisted population migration in which seed sources are moved climatically or geographically within their current ranges (green), even across seed transfer zones; e.g., moving western larch 125 mi (200 km) north within its current range. Seed sources can also be moved climatically or geographically from cur- rent ranges to suitable areas just outside the range to assist range expansion, such as moving seed sources of ponder- osa pine into Alberta, Canada. For assisted species migration, species could be moved far outside current ranges to prevent extinction, such as planting Florida torreya in States north of Florida (Torreya Guardians 2008). (Terms were reused from Ste-Marie and others 2011 and Winder and others 2011; distribution maps were adapted from Petrides and Petrides 1998 and Torreya Guardians 2008.) From

Join a Flower Garden Banks Lionfish Research Expedition

Texas Lionfish Control Unit will again lead two expeditions of trained scientists and volunteer divers to the Flower Garden Banks National Marine Sanctuary in 2019. These 4-day research expeditions, in partnership with NOAA-Flower Garden Banks, Ripley’s Aquarium, National Marine Sanctuary Foundation and M/V Fling will remove lionfish (Pterois volitans) from the sanctuary and gather scientific data for lionfish research. Scheduled dates are June 9-13, 2019 and August 25-29, 2019. For more information, including eligibility requirements, registration information, and goals and objectives, go to


Invasive Spotlight:
Spotted Knapweed
(Centaurea stoebe ssp. micranthos)

Spotted knapweed is an herbaceous biennial or perennial plant that readily invades open areas. It begins as a basal rosette of deeply lobed, pale, grayish green leaves approximately 8 in. (20 cm) long. In its second year it produces the flowering stems, which are 1-4 ft. (0.3-1.2 m) tall, stiff, hairy, and branched. Stem leaves are alternate and may be slightly lobed or linear. Leaves become progressively smaller and less lobed toward the tip of the stem.

The small purple-to-pink flowers bloom in the early summer at the ends of the branches. Bracts around the flower head have distinctive vertical veins below a black triangular shaped spot on the bract tip that gives the flower heads the spotted appearance that gives the species its name (see photo). The fruit is an erect, slender green pod that turns pale brown when mature. The copious seeds are wind-dispersed.

Spotted knapweed invades a wide variety of habitats including pastures, open forests, prairies, meadows, old fields, and disturbed areas. It displaces native vegetation and reduces the forage potential for wildlife and livestock. It is native to Europe and western Asia. It was accidentally introduced into North America in contaminated alfalfa and clover seed in the late 1800s.

This invasive species occurs on the noxious/regulated plant lists of 16 states. 

So far, spotted knapweed has been officially found in only two Texas counties, but it likely occurs in more.  Please be on the lookout for it. If you are an Invaders of Texas citizen scientist, please report it using the Texas Invaders mobile app as you have been trained. If not, please report it here, including your contact information, the location of the plant(s) 
(GPS coordinates if possible), and photo(s) that can be used to identify the plant.

Follow this link for more information on spotted knapweed.

spotted knapweed flowerhead

Note dark tips of the bracts. Credit: Chris Evans, University of Illinois,

spotted knapweed rosette

Credit: Joseph M. DiTomaso, University of California - Davis,

More News

Broad Impacts from Lake Trout Invasion in Yellowstone
Scientists analyzed data spanning more than four decades and concluded that the impact of lake trout (Salvelinus namaycush) in Yellowstone Lake -- in particular, the decline of native cutthroat trout (Oncorhynchus clarkii) -- has cascaded across the lake, its tributaries and the surrounding ecosystem. Learn more at

Non-Native Pest-Controlling Wasp Identified in Canada Prior to Formal Approval
Thought to be Canada's most promising potential defense against the brown marmorated stink bug (Halyomorpha halys) (a globally spreading pest of various fruits and vegetables), the samurai wasp (Trissolcus japonicus) has been considered for future release in the country in recent years. However, prior to any formal decision and approval for release, the parasitoid has been found to be already present at a heavily infested site in British Columbia. Learn more at

How Fungi Influence Global Plant Colonization
The symbiosis of plants and fungi has a great influence on the worldwide spread of plant species. In some cases, it even acts like a filter. Learn more at

Rising Global Shipping Traffic Could Lead to Surge in Invasive Species
Rising global maritime traffic could lead to sharp increases in invasive species around the world over the next 30 years, according to a new study. The findings suggest that shipping growth will far outweigh climate change in the spread of non-indigenous pests to new environments in coming decades. Learn more at

How Tree Diversity Regulates Invading Forest Pests
Relationships between tree diversity and pest diversity follow a hump-shaped curve. That's the finding of a national study of US forests that compared two county-level data sets. To better understand how nonnative insects and diseases invade U.S. forests, researchers tested conflicting ideas about biodiversity. Learn more at

Birds Bug Out Over Coffee
New research has found that birds are as picky as coffee snobs when it comes to the trees they'll use after migrating to their summer habitat. Migratory birds prefer foraging in native leguminous tree species over non-native and many other trees used on many coffee farms. The findings will help farmers choose trees that are best for both birds and business. Learn more at

Dozens of Non-native Marine Species Have Invaded the Galapagos Islands
The Galapagos Islands, famous for its giant tortoises, swimming iguanas, and numerous species found nowhere else, is a protected World Heritage Site, but that doesn't mean it's immune to the invasion of non-native species. Recent research concentrated on the marine environment, which is less well studied than the terrestrial environment, and found that there are about ten times more non-native species than previously recorded. Learn more at Texas Public Radio.


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 detect and report invasive species as citizen scientists. Workshops, which are free, are designed to introduce participants to invasive species and the problems they cause, cover aspects of invasive species management, and teach identification of local invasive plants, and to train participants to report invasive plants using the TX Invaders mobile application. The workshop is 7 hours long (usually on a Saturday, but scheduling is arranged with each individual host group). The workshop satisfies Master Naturalist training requirements.

Sentinel Pest Network workshops serve to increase the awareness and early detection of a set of particularly important invasive species, to help prevent their spread into Texas or their further spread within Texas. Participants learn to identify species such as the Emerald Ash Borer, Cactus Moth, Asian Longhorned Beetle, and other pests of regulatory significance, and to report them. The workshop is 3.5 hours long. The workshop satisfies Master Naturalist training requirements.

Upcoming Workshops:

Saturday, May 10, 2019
Invaders of Texas Workshop
Location: St. Michael's Catholic Church (Jasper, TX)
Contact: Lori Horne
Note: This workshop has a fee.

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