Cane toads (Rhinella marina) were imported from South America in the 1930 and introduced to several countries as an agricultural pest control but has since become highly invasive. The potent toxins produced by the glands in their skin are responsible for killing local predators, including goannas, snakes, and freshwater crocodiles, which lack natural defenses against these toxins. The loss of predators in these areas has caused an imbalance in the ecosystem and food chain.

In Australia, some populations of freshwater crocodiles (Crocodylus johnstoni ) have dropped by >70% due to the lethal ingestion of invasive cane toads. To reduce death rates, researchers developed a method to ‘teach’ crocs to associate cane toads as a food source to avoid. This method is called conditioned taste aversion (CTA).

In an area first invaded by cane toads, 2395 baits were deployed across four large gorge systems (where multiple water bodies meet). The survey used two types of bait: 1) toad carcasses with the toxins removed and a nausea-inducing chemical added, and 2) raw chicken necks (control). The observed population of crocodiles learned to avoid toad baits in a matter of days, while turning preference to control baits. The survey continued over the course of several years. Compared to control sites, where neither bait was used and crocodile mortality rates remained high, a positive impact on crocodile survival was observed at sites where bait was diploid.

As a result of this land management study, bait deployment completely prevented croc deaths in areas with well-established cane toad populations and decreased deaths by 95% in areas where toads more recently established (couple years). These programs are helping the populations of crocodiles return. Similar methods have been diploid to protect the yellow monitor lizard (Varanus flavescens) from predators. Who knows how else conditioned taste aversion could help rebalance vulnerable ecosystems.

Read the research: Ward-Fear et al., 2024

High-Tech Hound Detects Mounds

Solenopsis invicta, or the red imported fire ant (RIFA) is one of the most invasive, hard to eradicate, annoying pest ant in the U.S., and especially in Texas (Click HERE to read more about RIFA). Other than accidentally stumbling upon them, fire ant mounds can be difficult for the untrained eye to distinguish from mounds made by other ant species. Even some professionals find it challenging to verify identifications in the field because many small ants share similar mound construction characteristics and disturbance behavior. Searching large areas and locating all active RIFA mounds can also be challenging. Invasive fire ants create massive colonies with many mounds interconnected to each other underground. One or more mounds treated with pesticides or disturbed are known to be abandoned, while others in the colony erect new mounds elsewhere. This is one of the many reasons RIFA is so difficult to control.

Scientists at the Guangdong Academy of Forestry have created an unexpected helper called the CyberDog which uses a YOLOX learning model. The AI powered robot integrated with the YOLOX model was trained using images of 1118 RIFA mounds. This allowed it to automatically locate and identify nests with a precision rate of <90%. The CyberDog offers an eco-friendly alternative to the conventional methods of using pesticides or generalized insecticides, which can harm more than the intended target. The bot is not only able to distinguish between RIFA and other species, but between active and passive mounds. The CyberDog is programmed to press onto the suspected nest with its front paw which will initiate a disturbance response and trigger an aggressive rush of worker ants from the nest, providing a clear sign of active habitation. At the end of the trials, the bot was found to match the speed of trained inspectors but was able to identify 3x more nests with more accuracy. The robot can also be programmed to work during any time of day because it is not restricted or slowed by high temperatures.

Currently, the greatest limitation of the CyberDog is the battery life (about 30minutes) and the production cost compared to the traditional approach. As these limitations become lesser, the integration of AI trained robots in pest management could be a true help with invasive fire ant mitigation.

Read the research: Xin Su et al., 2024

Boxthorn Benefits Rare Rodent

The endangered greater stick-nest rat (Leporillus conditor) was declared extinct on the mainland by 1930 and is now only found on offshore islands away from invasive predators, such as cats and foxes, but birds of prey still pose a great threat. With the aid of a thorny invasive plant, these guinea pig sized rats may have found refuge from any flying menace.

African boxthorn bushes (Lycium ferocissimum) are an invasive weed found in Australia. It is a thorny bush with orange and redberries and purple flowers. The impenetrable thickets cause problems for cattle, and it is poisonous to people. However, a recent study found that greater stick-nest rats were more present in areas with a higher boxthorn abundance. These rodents likely shelter and nest in the boxthorn because the thorns and twisted thickets provide cover from predatory birds. When microscopic plant remains found in the fecal pellets were examined, boxthorn accounted for more than half of the rodent’s diet, even though boxthorn plants only represent 1/10 of the available vegetation. There are few cases of native animals utilizing and benefiting from invasive species, and researchers are encouraged with these findings. Boxthorn is considered one of the worst weeds in Australia. Further research is needed to better understand potential benefit compares to the destructive effects.

Read the research: Kraehe et al., 2024

Don’t Mess With Texas Citrus

TISI is offering FREE diagnostic services if you suspect your citrus has either the psyllid pest or the Citrus Greening pathogen, or you would like your citrus plants to be part of our screening survey.

The Asian citrus psyllid (Diaphorina citri) and the Citrus Greening pathogen (Candidatus liberibacter asiaticus) are threatening citrus in multiple Texas counties. By taking samples and monitoring the spread, it is easier to ensure that you and your neighbors are not affected. This pest and pathogen are extremely detrimental to Texas citrus, both economically and agriculturally. The presence of either can greatly affect citrus yield.

If you are interested in having your citrus trees checked or being part of the survey, please contact invasives@shsu.edu. If you are located within 200 miles of our headquarters, we can collect samples and/or provide traps and monitoring services. Otherwise, we will send you easy step-by-step instructions so you can do it yourself. Not only will we share the results and management strategies (where applicable), but you will become part of a multi-county monitoring survey that is striving to improve the health of Texas citrus!

Also Available: TISI offers educational workshops that highlight information about the Asian citrus psyllid, the pathogen Citrus Greening, and what you need to look out for in your own backyard. If you are interested in this, TISI will provide trapping materials, assist with management strategies, and more. Don’t waste another second.
Help us stop the spread!

This program is designed to provide the education needed for professionals and students who are managing or learning to manage invasive species. The courses include the most current invasive species identification, control, and management techniques, and how to comply with local and federal regulations.

Participants may register and enroll at any time, and will receive a certificate of invasive species management from NAISMA upon completion of the program.

All live webinars are open to the public. Recorded webinars are available to members of NAISMA.

NAISMA 2024 Webinar Schedule:

• September 18, 1pm CST- Stony Coral Tissue Loss Disease. REGISTER.
• October 16, 1pm CST- White-Nose Syndrome and Bats. REGISTER.
• December 18, 1pm CST- Canadian Biocontrol Experience: Past, Present and Future. REGISTER.

Learn about invasive flora and fauna in Florida, their effects on local nature, and how we can manage and prevent them. Register and join the free webinar and learn to recognize common invasive species in the state that are on the move.

Thursday, September 19, 4:30 - 5:30pm CDT

Pre-register here.

Come put your hands in the dirt at the Bandera Natural History Museum pollinator gardens. There are three gardens that need tending and as a volunteer you can tour the Museum for free. See HERE for more information.

September 11, 10:00 AM - 11:30 AM (Click HERE for more event dates)

267 Old San Antonio Highway, Bandera, TX 78003

Contact: Janis Jay Arterbury

• Use VMS CODE: BD-07-A Bandera Natural History Museum Pollinator Gardens

A Conversation about Invasive Plants presented by the Native Plant Society of Texas, Kerrville Chapter. The main topics are: What they are, why they’re harmful, and how we can do better for the environment. This program will discuss which and when plants are considered invasive and/or beneficial. Click HERE for more information.

September 10 @ 2:00- 3:00pm

Location: Riverside Nature Center, 150 Francisco Lemos Street, Kerrville, Tx 78028

No Registration Necessary
For questions, contact: Nancy Huffman, (832) 851-9866

Invasive Spotlight:

Asian Clam
(Corbicula fluminea)

Asian clams (Corbicula fluminea), also known as basket clams or golden clams, are small bivalves that can reach a length of 50mm, with a shell encircled with concentric ridges. Both dark and light shell morphs exist. Light shell morphs have straw yellow to greenish coloration on the outside and white on the inside. Dark morphs have dark brown on the outside and purple on the inside. However, the dark shell morphs are typically limited to the southwestern U.S.

These clams reproduce rapidly through self-fertilization. Each clam can release up to 2,000 juveniles per day, and more than 100,000 in a lifetime. Juveniles are only 1 mm long and take 1-4 years to reach maturity. The adult life span is between 1-7 years. Their cold-water tolerance adds to its success as an invasive species. They prefer shallow fresh or brackish waters (<3m) with sandy or fine gravel substrate but can be found in waters as deep as 10 meters. Individuals often bury themselves in the sediment.

Basket clams are known as a biofouler of electrical and nuclear power plants across the U.S. as they are carried into the plant via the water intake pipes used for cooling purposes. Once inside the plant, these mussels can clog condenser tubes, raw service water pipes, firefighting equipment, and decrease the overall efficiency of energy generators. Not much is known about the possible threats the clam currently possesses on the native ecosystem. They have been added to the diet of some native species and are known to be eaten by humans. However, this is not recommended, as clams sourced from polluted waters are known to have different quantities of toxins absorbed in their gut (those strained from the water). These clams rely on human dispersal for the expansion of geographic distribution. To prevent additional spread, please remember to Clean, Drain, and Dry!

Basket clams are currently found in multiple Texas riverways, as well as along both U.S. coastlines and most of the heartland. Only a few U.S. states are free of these clams. For more information, see the TexasInvasives.org species page. If you believe you have seen any basket clams, please contact invasives@shsu.edu. We will review your report and get back to you as swiftly as possible. Citizen Scientists are often our first line of defense. We appreciate your diligence and dedication.

Get Involved Today!!

The Texas Invasive Species Institute (TISI) and The Texas Research Institute for Environmental Studies (TRIES) has many surveys and projects underway. These facilities strive to provide yearly invasive species presence and absence data to the authorities. Pre-screening is one of the first lines of defense in early detection.

With the aid of the public and citizen scientist, we could cover a much wider area, and gather more substantial amounts of data. When it comes to protecting our environment, there is an opportunity for everyone! Together we can make a difference, one research project at a time.

See how you can get involved by reading the projects listed below or see all the available projects on the Texas Invasives website HERE.
 

Enjoy monthly videos about invasive species and/or people willing to teach us more about them. There are some amazing citizens and professionals around the world that poke, prod, chase, dive, and investigate everything they can about these alien invaders. Jump into this cinematic rabbit hole. You never know what new wonders you may discover.

NASA ARSET: Introduction to the Monitoring of Invasive Species with Remote Sensing Tools, Part 1/3. NASA video.

Part one of a three-part webinar series is an introduction to the monitoring of invasive species using remote sensing tools and applications with a program called ARSET or Applied Remote Sensing Training Program. The link will also provide a rout to all training material. Part 2/3: Monitoring of Aquatic Invasive Species. Part 3/3: Mapping Invasive Grassland Plant Species.

USU Researchers Studying Tens of Thousands of Trees to Help Predict Future Forest Growth. Utah State University.

Researchers are trying to learn how forests are changing. Things like bark beetles, invasive pathogens, fire, and drought can affect a forest. Since trees live much longer than humans, A LOT of trees must be observed to gather the information that is needed.

Aquatic Invasive Species Module 1: Introduction to Aquatic Invasive Species. University of Florida/IFAS Tropical Aquaculture Laboratory.

Module 1 reviews the seven terms used to describe a species within a certain area: native, nonnative, introduced, established, invasive, nuisance, and range change. This is the first of five aquatic invasive species training modules. 2) Invasion pathways, 3) Invasion process, 4) Impacts, 5) Getting to Know Florida’s AIS.

Invasive Chinese Mystery Snails Spreading at Rapid Rate Across America, Over 1 Million Removed In Some Areas
The Chinese mystery snail (Cipangopaludina chinensis) has started popping up in lakes from Texas and Georgia. Authorities say eradication of these snails in America is not likely possible. insideedition.com

Invasive Fish Found in The Wild for The First Time in Texas
TPWD reported that hybrid peacock cichlid is being caught in Central Texas. These are non-native aquarium pets that have been released into local waters. chron.com

Quantifying Potential Impact of Feral Hog Predation on Coastal American Alligator Nests
Researchers examine the impact of feral hog (Sus scrofa) predation on American alligator (Alligator mississippiensis) nests in some habitats and landscapes compared to others. phys.org

Piranha Like Fish Caught in Lake Meredith
Red-bellied pacu (Piaractus brachypomus) have been caught in Texas again, this time in Lake Meredith, Sanford, Tx. These fish are related to piranha but have surprising differences. abc7amarillo.com

A New Advanced Framework to Assess the Impact of Invasive Plants on Ecosystems
New technology and techniques are combined to create a framework to better assess the impact of invasive plant species on ecosystems over time, in different environments. phys.org

Scientists Sound Alarm Over Invasive Species Wreaking Havoc in Local Forests: 'There's Something Geographic About That Area That Makes It More Susceptible'
The balsam woolly adelgid (Adelges piceae) is wreaking havoc on fir trees in Utah. The insect's impact is already visible in popular recreation areas near Salt Lake City. thecooldown.com

Trees Stripped by Invasive Caterpillars Muster Defenses That Can Harm Native Insects, Research Shows
Spongy moth (Lymantria dispar) caterpillars can strip entire stands of trees of their leaves. A recent study examined the aftermath of a huge invasive moth infestation and how it affected the trees. phys.org

Researchers Set to Release Droves of Wasps in Effort to Combat Invasive Species Wreaking Havoc on Farms: 'It's A Win for Everybody'
Spotted wing drosophila (Drosophila suzukii) is becoming an agricultural nuisance for many farmers across the U.S. The U.S. Department of Agriculture has approved using the samba wasp (Ganaspis brasiliensis) as a biocontrol. thecooldown.com

Killings Of Invasive Owls to Ramp Up on US West Coast in A Bid to Save Native Birds
Barn owls have become not only invasive throughout west coast forests, but they are crowding out native owls. U.S. wildlife officials are prepared to take action. phys.org

Fresh Warning on Fire Ants in Queensland as Suppression Efforts Struggle to Halt Spread
Specialists say the densities of the red imported fire ants (Solenopsis invicta) in Queensland is approaching what is seen in Texas. theguardian.com

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, teach identification of local invasive plants, and 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.