February 2018
The San Marcos Spring Polespear Tournament Is Part of National Invasive Species Awareness Week

February 26 – March 2 is National Invasive Species Awareness Week, organized by the Reduce Risks from Invasive Species Coalition. Various activities are planned across the United States. You could be involved! If you are an Invaders of Texas citizen scientist, consider doing some mapping this week, perform some removal or restoration, or contact your Satellite Group to see what can be done locally. Go to the National Invasive Species Awareness Week website for more information.

If you scroll down to the map on the NISAW website, you'll see that there is one listed event in Texas: the Spring Polespear Tournament. The tournament, an effort to remove invasive fish and snails, as well as litter, from the San Marcos River, runs through March 5. For more information, go to the Spring Polespear Tournament website.


Zebra Mussel and Giant Salvinia Continue to Spread in Texas

Unfortunately, zebra mussels (Dreissena polymorpha) and giant salvinia (Salvinia molesta) continue to expand their range in Texas. This February, Texas Parks and Wildlife Department (TPWD) announced that giant salvinia (GS) was discovered in Lake Athens and Lake Nacogdoches. In both cases, biologists suspect the GS was introduced by a boater or angler. The infestation in Lake Athens was relatively small, allowing the TPWD Brookeland aquatic habitat enhancement team (AHE) to deploy a containment boom. That will be followed by herbicide treatments. According to Brookeland AHE team lead John Findeisen, “The containment boom is a critical component of our rapid response efforts to eradicate giant salvinia at Lake Athens. Concentrating giant salvinia in an area helps prevent further spread and increases the efficiency and effectiveness of herbicide treatments, which is the next phase of our response at Lake Athens. Following that we should know fairly soon if eradication is a real possibility at the lake.” TPWD's news release also provides angler with instructions on how to navigate the boom.

While the Lake Athens infestation is relatively small, the one in Lake Nacogdoches covers a total of 30 acres in multiple locations. The infestations will be treated with a combination of giant salvinia weevils (Cyrtobagous salviniae) and careful application of contact herbicide on larger mats of the invasive plant. “We will use weevils in the areas where the giant salvinia is being contained by other vegetation and only treat mats of salvinia when they form,” said Findeisen. Here's a video on TPWD's use of the salvinia weevil in Texas.

This February, TPWD also upgraded the zebra mussel classifications of Lake Austin and Lady Bird Lake. Lake Austin’s classification has been upgraded to infested, meaning it was confirmed to have an established, reproducing population of zebra mussels, after TPWD and Lower Colorado River Authority (LCRA) staff found larvae and several size classes of adult in multiple locations. Lady Bird Lake has been upgraded to suspect, meaning zebra mussels or their larvae have been found at least once, after LCRA found several larvae in a plankton sample. These discoveries come less than a year after zebra mussels were first identified upstream in Lake Travis in June 2017.

salvinia 2

Credit: TPWD

zebra mussels

Credit: Amy Benson, U.S. Geological Survey



Nutria Have Returned to California

Nutria (Myocastor coypus), the invasive semi-aquatic rodent, has returned to California. Eliminated from the state in the mid 1960s, 20 of them were found in the state during 2017. Unfortunately, they are breeding in the San Joaquin Valley, which means they are spreading. It is a mystery as to how they reappeared.

The invasive animals can grow up to 2.5 feet, not counting a foot-long tail, and weigh up to 20 pounds. They destroy wetlands and flood control systems, cause severe soil erosion and damage levees. They also degrade water quality and can contaminate drinking supplies with parasites and diseases transmissible to humans, livestock and pets. When they reach reproductive maturity at six months, they reproduce at an astonishing rate. The California wildlife department reports "one female nutria can result in more than 200 offspring, which can disperse as far as 50 miles." In Texas, nutria are "found from Central Texas eastward and on the Texas Coast in marshes, swamps, ponds and lakes," according to the Texas Parks and Wildlife Department.

Ironically, the eradication effort in California is hampered by the fact that the nutria is classified as an invasive species. Under California law, that means it is illegal to possess, own, transport or eat them. Instead, authorities area asking people to contact the California Department of Fish and Wildlife if they find one.

a nutria

Credit: John and Karen Hollingsworth,U.S. Fish and Wildlife Service

map of distribution of nutria in Texas

Distribution of nutria in Texas.

Texas Invasive Plant and Pest Conference to Be Held October 23-26

Due to the impact that the uncertainty in federal funding is having on many of our likely participants, the Texas Invasive Plant and Pest Council has decided to postpone the Conference until October 23 - 26. Deadlines have been posted on the Conference website. Check back at that website and our Facebook page for more information as it becomes available. We will be opening abstract submission this month. Information will also be updated here in the iWire.



Invasive Species

Giant Salvinia
(Salvinia molesta)

A popular aquarium plant, this Brazilian aquatic fern was first discovered in South Carolina in 1995 and in Texas in 1997. It has become one of the most destructive aquatic invasive plants in Texas. It thrives in slow moving warm bodies of water, quickly creating dense mats that cover the surface, which can deplete oxygen levels and block sunlight. It can quickly choke out the native vegetation that supports the ecosystem. In the US, it reproduces mainly by budding from nodes or broken stems. It has spread throughout rivers and lakes in the Southern half of the US and Hawaii, though the majority of high infestations are in Texas and Louisiana. It has infested at least 21 Texas lakes since it was was first discovered on Toledo Bend in 1998. The invasive plant has been newly introduced or reintroduced at six Texas lakes since 2017: Lake Murvaul, Lake Palestine, Martin Creek Lake, Lake Fork, Lake Nacogdoches and now Lake Athens (see above).

Giant salvinia is a rootless, floating fern. Emergent groups of leaves (fronds) are oblong and flat or semi-cupped, and grow in chains. Leaves grow in pairs and are approximately 1/2 inches wide and 1 inch long. The upper surface of the green leaves is covered with rows of white, coarse hairs, acting as a water repellent.

Because the giant salvinia reproduces mainly through budding, preventing the spread of the aquatic fern involves cleaning all recreational watercraft and equipment thoroughly before leaving a suspected infestation area. Learn more about giant salvinia, how it threatens Texas waterways, and where it's found at this information page and Texasinvasives.org's species profile.

If you find a suspected infestation please report this species right away.

Robert Videki, Doronicum Kft.,

More News

Asian Ticks Mysteriously Turned Up on a New Jersey Sheep
How did a tick that's native to East Asia — the longhorned tick or bush tick (Haemaphysalis longicornis) — make it to rural New Jersey? That's the question puzzling researchers. The backstory involves a panicky sheep owner, tick-covered humans and a pair of pants stuck in the freezer. For more details about this fascinating story, see npr.org. Warning: this story is likely to make your skin crawl!

Massive Crayfish That Didn't Exist 25 Years Ago Are Capable of Cloning Themselves — And It's Taking Over Europe
The marbled crayfish (Procambarus virginalis) is an amazing animal: it is capable of cloning itself, it's huge, it produces hundreds of eggs at a time, and it has existed on this earth for less than 30 years. It is highly invasive, spreading through Europe and Madagascar. For more details about the marbled crayfish, its impacts and the genetic research that established it as a new species, see the article at Businessinsider.com and the original article in the New York Times.

Alien Honeybees Could Cause Plant Extinction
New research indicates that introduced 'alien' honeybees are competing for resources with native bees and threatening the survival of plants that rely on interactions with specific pollinators. Read more at sciencedaily.com.

Nursery Stock, Homeowner Preferences Drive Tree Diversity in Salt Lake Valley
What factors shape the formation of a new urban forest? Researchers' survey of tree species diversity in the Salt Lake Valley found that, perhaps not so surprisingly, diversity can be shaped by the species available in nurseries and the preferences of the homeowners, and even the tree selections of their neighbors. Read more at sciencedaily.com.

How Cities and Towns Can Prepare for Emerald Ash Borer Invasion
In Pennsylvania, where emerald ash borer (Agrilus planipennis) has been present since 2007, municipalities have found successful ash-management plans under guidance of the state's Department of Conservation and Natural Resources, and they offer a model for other regions to follow. A new guide outlines a set of four options for communities to choose from as they plan for the impact of the emerald ash borer. Read more at sciencedaily.com.

Invasive Insect Species Overlooked as a Result of a Shared Name
An invasive leaf-mining moth has been gradually expanding into northern Europe under the cover of a taxonomic confusion for a period likely longer than 60 years. It has been sharing a name with another species. For the first time, recent research properly distinguishes between the two insects and tries to reconstruct the invasion of the 'true' moth behind the name of Antispila treitschkiella. Read more at sciencedaily.com.

Grey Squirrels Beat Reds in 'Battle Of Wits'
Problem-solving powers may help to explain why grey squirrels (Sciurus carolinensis) have taken over from native red squirrels (S. vulgaris) in the United Kingdom (where they outnumber the red squirrel by more than 15 to 1), according to new research. Read more at sciencedaily.com.

Intensive Forest Biomass Harvest Linked to Fire Ant Colonization, Decreased Invertebrate Diversity
In North Carolina and Georgia, the woody debris left on the ground after timber cutting in pine stands is harvested for the manufacture of wood pellets. Removing almost all of the woody debris can open the door to red imported fire ant (Solenopsis invicta) colonization, according to in-depth studies. Learn more at phys.org.

Few Chicagoland Wetlands Left Without Non-Native Species
The wetlands in and around Chicago are overwhelmingly invaded by non-native plants, according to a new study. The study, which pulls together species occurrence data from over 2,000 wetlands in the urban region, is the first to describe wetland invasion patterns on such a large scale in the Chicagoland area. Read more at sciencedaily.com.


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 iwire@texasinvasives.org.

Sentinel Pest Network and Invaders of Texas 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 Texasinvasives.org designed to help organize and track volunteer-based eradication efforts.

Upcoming Workshops:

Friday, April 20, 2018
Location: Phil Hardberger Park Ecology Center (San Antonio, TX)
Contact: Rachel Cywinski


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