Texas’ Rarest Dragonflies Tied to Rare Natural Community, Pitcher-Plant Bogs

Eastern Texas is home to two of what could arguably be among the rarest dragonflies in North America. The Texas emerald, Somatochlora margarita, is known from just nine Texas counties and three Louisiana parishes. Although it may be the most common dragonfly in areas where it occurs, it is rarely encountered because of its habit of flying and perching at tree-top level. The Texas emerald was petitioned for federal listing under the U.S. Endangered Species Act in 2011 and is pending a 12-month review by the U.S. Fish and Wildlife Service.

Rarer still, the sarracenia spiketail, Cordulagaster sarracenia, was only just described in 2011 and is currently known from five Texas counties and a single Louisiana parish. Although the range for the two species closely overlaps, observations of the sarracenia spiketail are patchier, partly due to its’ short flight season (15 Mar – 29 Apr) and its strong association with pitcher plant bogs: a rare natural community threatened by woody encroachment resulting from decades of fire suppression.

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A pitcher plant bog. Photo by John Abbott.

For both species, substantial data gaps pose challenges to evaluating the conservation status for these species, let alone implementing proactive conservation measures. However, with funding provided by sales of the Wildlife Diversity Program’s Conservation License Plates, Dr. John Abbott, Director of Museum Research and Collections at the University of Alabama, has started to fill in those gaps.

Dr. Abbott is no stranger to dragonfly research. Having literally written the book on Texas dragonflies…twice, he formally described the adult sarracenia spiketail and the Texas emerald nymph. All dragonfly nymphs are aquatic, so identification of the aquatic habitat in which nymphs reside is absolutely critical for conservation of the species. Despite Dr. Abbott’s expertise, no Texas emerald nymph had ever been seen in the wild: the nymph was described from an individual raised in the laboratory from an egg.

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The nymph of the Texas emerald, Somatochlora margarita. Photo by John Abbott.

Extensive surveys of streams and bogs in the vicinity of adults had repeatedly failed to produce nymphs. That changed, in the spring of 2015 when, using his knowledge of dragonfly biology, Abbott starting sampling more unusual habitats including crayfish burrows and sphagnum-covered stream banks fed by pitcher plant bogs. It was in this latter habitat, 1.5 feet inside deeply undercut stream banks, that two Texas emerald nymphs were finally located half a century after the adults were first described. This discovery sheds light on why the nymphs have been so elusive: they practically live underground in a restricted habitat. It also highlights that, like the sarracenia spiketail, long-term survival of the Texas emerald is closely tied to the persistence of pitcher plant bogs.

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Habitat of the Texas emerald, Somatochlora margarita, nymph. Photo by John Abbott.

Although the relationship between the sarracenia spiketail and pitcher plan bogs is known, because of the sensitive nature of those habitats and the dragonfly’s apparent rarity, biologists have expressed concern over population sizes for the species. Indeed, of the six locations where the species has been documented, only two of those sites have yielded more than a single sarracenia spiketail. So, Dr. Abbott set out to estimate population sizes at those two sites using established mark-recapture methods. The results were less than encouraging.

To put those results into perspective, consider an earlier mark-recapture study of the Hine’s emerald dragonfly: the only federally endangered dragonfly in the coterminous U.S. That study resulted in 331 captured and marked individuals, 88 of which were later recaptured. That resulted in an estimated population size of 1023 individuals at a single site: not exactly a booming population. Now consider Dr. Abbott’s efforts. At two sites surveyed, a combined total of only 20 individuals were captured and marked, four of which were later recaptured. Those numbers are so low as to prevent a statistical estimation of population size. Granted, those two studies aren’t directly comparable: Hine’s emerald has a longer flight season than the sarracenia spiketail, and the spiketail mark-recapture effort was hindered by cloudy weather, which reduces dragonfly activity and detectability. Nevertheless, the numbers still tell a concerning story about the rarity of this species.

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Sarracenia spiketail, Cordulagaster sarracenia, marked for population estimate study. Photo by John Abbott.

For both the Texas emerald and the sarracenia spiketail, the findings of the Conservation License Plate-funded research presented here demonstrate the importance and sensitivity of pitcher-plant bogs for Texas’ rarest dragonflies. However, the story is not without hope. Management practices that restore and maintain pitcher-plant bogs are well-established. Exclusion of feral hogs, periodic burns to mimic historic fire regimes, and, in some instances, mechanical control of woody encroaching species can restore pitcher-plant bogs, which not only provide habitat for dragonflies, but for a host of other rare plant and animal species. These management practices and their results can be seen first-hand in healthy bogs at Texas Parks and Wildlife’s Gus Engeling Wildlife Management Area in Anderson County Texas.

Texas Kangaroo Rat: Getting Ahead of the Curve

Credit: painting by Elizabeth McClelland from Kays and Wilson's Mammals of North America, © Princeton University Press (2002)
Credit: painting by Elizabeth McClelland from Kays and Wilson’s Mammals of North America, © Princeton University Press (2002)

Did you know that Texas has a kangaroo rat with its name-sake? Texas kangaroo rat is a fitting name as this is the largest of the five kangaroo rat species found in the state. The Texas kangaroo rat is the only species found in its historic range with a long, thick, white-tipped tail. Kangaroo rats are unusual for rats when it comes to their appearance (furry tail) and movement patterns. They hop on their back feet like kangaroos, and when males battle each other they jump at their opponents with their back feet using their back toes as weapons.

The Texas kangaroo rat (Dipodomys elator) is only known to occur in a relatively small region historically, where the Great Plains prairie meets the Rolling Plains. Its historic habitat is encompassed by a 15-county area in north-central Texas starting at the base of the panhandle and extending east along the Red River, including a small area of southern Oklahoma. The Texas kangaroo rat is considered to be the only mammal endemic to this region.

Credit: Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy — Migratory Bird Program, Conservation International — CABS, World Wildlife Fund — US, and Environment Canada — WILDSPACE.
Credit: Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy — Migratory Bird Program, Conservation International — CABS, World Wildlife Fund — US, and Environment Canada — WILDSPACE. Image provided by Smithsonian Institute.

Because so little is known about this species, and the data we do have indicates a decline in population, the Texas kangaroo rat is considered a Species of Greatest Conservation Need in the Texas Conservation Action Plan and is listed as a state threatened species by Texas Parks and Wildlife Department (TPWD). Research surveys conducted in 2002 documented their occurrence in only five of 15 counties. When those five counties were surveyed again in 2011, none were found (note: that was a year of exceptional drought). In 2009, Wild Earth Guardians petitioned the species for listing under the U.S. Endangered Species Act (ESA). U.S. Fish and Wildlife Service (USFWS) is in the process of conducting a 12-month review and will examine all available data (best available science) to determine whether the need to list this species as threatened or endangered is warranted.

In order to gain much-needed information about the current status, distribution and habitat needs, Texas Parks and Wildlife Department (TPWD) is funding a research project with Texas State University that will begin this fall. The Texas Comptroller’s Office is also funding a research project that Texas Tech University is currently conducting which includes examining genetic health and population status. In addition to these two research projects, a researcher from Tarleton State University received Section 6 funds through TPWD last year to evaluate the genetic structure of this species from museum specimens that is currently ongoing.  The combined results of these three research projects will provide a better understanding of the current status, habitat needs and reasons for its decline, and will help identify management actions needed to protect and enhance populations of this unique Texas species. The data yielded from these three studies will provide the most current data to be included with historical research data as “best available science” for USFWS to consider, along with consideration of any and all conservation efforts in place to protect this species, before a final listing determination is made.

In September 2015, researchers from Texas State University met with TPWD Wildlife Division staff and Natural Resource Conservation Service (NRCS) agents who work directly with landowners in the counties within the Texas kangaroo rat’s current and historic range to discuss research needs. The goals of that meeting was to help prepare TPWD biologists and other natural resource professionals to inform landowners about funded-research efforts, explain what providing access to private lands for research would entail, explain the role landowners can play to help reduce the need for listing the species, and to explain what it could mean to the landowner if this species is listed in the future.

TPWD and NRCS staff meet with Texas State University researchers at Caprock Canyons State Park in September, 2015.
TPWD and NRCS staff meet with Texas State University researchers at Copper Breaks State Park in September, 2015.

Working with private landowners is the key to success in conservation and protecting this and many other rare species in Texas. Our best chance at reducing the need for federal protection of rare species is through developing partnerships with landowners willing to provide access to private property for field investigations and willing to voluntarily implement best management practices to benefit this species. The lesser prairie chicken and dune sage brush lizard are two examples of rare species in Texas that have realized the benefits of partnering with landowners through conservation agreements. Such partnerships and agreements successfully influenced USFWS listing decisions through the voluntary protections provided to those species occurring on private lands, and thus reduced the need for federal oversight. Let’s continue to work together proactively to protect the biodiversity of Texas that we value so greatly.

The Texas Arachno-Challenge I

Texas brown tarantula, Aphonopelma hentzi. Photo by Ben Hutchins.
Texas brown tarantula, Aphonopelma hentzi. Photo by Ben Hutchins.

Texas is blessed with a rich diversity of eight-legged critters. Few people realize, however, the impressive array of very different arachnids that you can find in Texas. Specifically, of the 11 orders of arachnids currently alive, Texas is the only U.S. state where you can find them all (we’re number one!).

What does that mean? I think a few examples of orders of animals that we may be more familiar with will help add significance to the statement. First example: all snakes and lizards across the world, belong to a single order: the Squamates. Example two: dogs, cats, bears, raccoons, mongooses, hyenas, and walruses all belong to a single order: Carnivora. Whales and dolphins belong to a different order, and bats belong to a third. In all, there are just under 20 mammal orders in the world (if you don’t count weird egg-laying mammals like the platypus ), and you would have to travel to several continents (and the ocean) to see them all.

The harvestman, Dalquestia formosa. Photo by Ben Hutchins.
The harvestman, Dalquestia formosa. Photo by Ben Hutchins.

But for arachnids, you can see all 11 without ever leaving the state. That’s the Texas Arachno-Challenge. So, let’s look a little closer into what it takes to meet the Texas Arachno-Challenge.

Several arachnid orders are easy and we won’t spend much time on these. If you have ever seen a spider, a daddy-longlegs (also called harvestmen), or a scorpion, you have knocked out three orders already (Araneae, Opiliones, and Scorpionida). These are abundant and widespread across must of the U.S., so we’ll move right along. Chances are, if you go outside much at all, you’ve seen a tick or gotten chiggers: there’s your 4th order (Acari), which includes all mites. These are also widespread around the world so we won’t talk about them either.

Undetermined pseudoscorpion. Photo by Dr. Jean Krejca, Zara Environmental LLC.
Undetermined pseudoscorpion. Photo by Dr. Jean Krejca, Zara Environmental LLC.

Now we’re getting into what may be new territory for some folks. Pseudoscorpions (Pseudoscorpionida) are common and widespread across the U.S. but rarely seen. They are small (most could comfortably walk around on the tip of a pencil eraser) and typically found under rocks and especially in soil and leaf litter. Several species also occur in caves, and Texas is home to one federally endangered cave-adapted pseudoscopion: the Tooth Cave pseudoscorpion (Tartarocreagris texana).

If you want to check this order off of your list, go to your nearest vegetated greenspace with a magnifying glass. Get comfortable with your face as close to the soil as your eyes can focus (a plastic tray to put some soil in may help) and patiently look through the soil and under rocks. You’ll know it when you see it: a tiny scorpion with no tail.

Not all arachnids are small. For the next three orders, which include some of our largest arachnids, your best bet is a trip to the Chihuahuan Desert of the Trans-Pecos, but to learn what other strange Texas creatures are part of the Texas Arachno-Challenge, you’ll have to wait until next week for The Texas Arachno-Challenge II.

Texas Nature Trackers Spotlight: Crawfish Frog (Lithobates areolatus)

Crawfish frog occurrences, historic (brown) and recent (blue).

The Texas Nature Trackers Herps of Texas Project (HoTX), needs your help to document populations of Crawfish Frog in Texas!  Crawfish frogs were formerly found in prairies throughout East Texas, but today they are only known from a few remnant populations.  The map depicts historic localities of the species (brown) as well as recent observations (blue).  Any observations are valuable, especially if you can find them in a county without a recent detection.

Habitat: The crawfish frog occurs in prairies and other grasslands, meadows, woodlands, and semi-permanent wetlands. They spend most of their lives in crayfish and gopher burrows, but under the right conditions they will emerge to breed in ephemeral ponds up to one mile from their resident burrow.

Description: The crawfish frog is related to leopard frogs and the bullfrog and has a similar body shape. The crawfish frog grows from 2.2 to 3.0 inches in length.  This species has a distinctive call that can be heard up to a mile away.

Finding Crawfish Frogs: The best time to look for this species is at night after a significant rain when the air temperature exceeds 50°F (10°C) between February and May.  Calling males may be detected over great distances. Please document observations with a sound recording and/or a photo. When possible, photos should include a scale.

Photo by Scott Wahlberg; HoTX observation 403266.
Photo by Scott Wahlberg; HoTX observation 403266.

Road Surveys: A good method for detecting this species is to conduct road surveys through appropriate habitat.  If conducting a road survey, concentrate on roads with little traffic and where you can safely stop.  Surveyors should stop every mile and listen for calling frogs for at least 30 seconds (with the car engine turned off). Location (GPS coordinates), air temperature, habitat, behavior (i.e. calling, crossing road), number of individuals and any other details (i.e. predation, other species present, mortalities) can be submitted online to the HoTX project.  If there are historic localities in your area, you can get in touch with us and we may be able to provide more specific information on localities with historic records.

Cullen Hanks : Texas Nature Tracker Biologist

Andy Gluesenkamp: TPWD Herpetologist

First Comprehensive Survey of Monahans Sandhills Endemic Insects

Sand dune and researcher at Monahans Sandhills State Park. Courtesy Scott Longing.

The Mescalero-Monahans sand dune systems of southeastern New Mexico and western Texas are known for their unique biodiversity including whipscorpions, scorpions, and the dunes sagebrush lizard.  A new dwarf morning-glory species was described from the region just this year.  Further contributing to the biological diversity of this system are nine endemic insect species.  Five of these species (the beetles, Anomala suavis, Nicagus occultus, Prionus spinnipenis, and Trigonoscutoides texanus as well as a Jerusalem cricket, Stenopelmatus monahansensis) are currently known only from the Monahans sandhills of western Texas, with the remaining four species (the beetles, Epitragosoma arenaria, Polyphylla monahanensis, Polyphylla pottsorum, and Prionus arenarius) occurring in both the Monahans sandhills of Texas and Mescalero Sands of southeastern New Mexico.  All nine of the insects are herbivorous and plant communities of the sandhills likely constitute an important food source, especially for the insect’s larvae that spend most of their lives below the surface of the sand.

Monahans Jerusalem Cricket (Stenopalmatus monahansensis). Courtesy Scott Longing.

These sand-dune associated insects are all considered Species of Greatest Conservation Need in Texas Parks and Wildlife Department’s (TPWD) Texas Conservation Action Plan (TCAP).  Little to any formalized research has been conducted on these insect species since their original scientific descriptions.  In 2013, the Nongame and Rare Species Program at TPWD funded a proposal by Dr. Scott Longing of Texas Tech University to conduct the first comprehensive survey of these insects in Texas.  Funding for this project was made possible through TPWD’s State Wildlife Grant Program which is focused on supporting conservation aimed at preventing species decline and avoiding the need to list under the Endangered Species Act.

The goal of Dr. Longing’s ongoing study is to better define species distribution and habitat in Texas in order to establish baseline occurrences for the nine endemic insects; a previously unavailable data product.  Such data are critical to an accurate understanding of a species actual conservation status.  To learn more about this project, and to view more images, visit Dr. Longing’s Research Highlight: Invertebrates of Monahans Sandhill.

Desert Massasauga: Results of Recent Genetic Work

massassauga_Hibbitts_copyrightThe Massasauga (Sistrurus catenatus) consists of three subspecies: the Eastern (S. c. catenatus), Western (S. c. tergeminus), and Desert Massasaugas (S. c. edwardsii).  Relationships among these subspecies pose challenges for conservation and management in Texas where both Western and Desert Massasauga subspecies occur.  The Western Massasauga has no special state or federal status, while the Desert Massasagua has been petitioned for federal listing under the U.S. Endangered Species Act.

In 2012, to better define the status of Massasauga subspecies in Texas, the Nongame and Rare Species Program at Texas Parks and Wildlife Department funded a genetic study conducted by researchers with the Institute of Renewable Natural Resources at Texas A&M University. This work was made possible through TPWD’s State Wildlife Grant Program.  Ryberg et al. (2013) used nuclear and mitochondrial DNA variation to define the geographic relationships between Western and Desert Massasaugas in Texas and adjacent states.  The researchers also assessed baseline population structure throughout the state and discussed the establishment of potential management units for Desert Massasauga should listing occur.

They found strong evidence that the Western and Desert Massasaugas are genetically indistinguishable for the genes investigated. Within the Western-Desert Massasauga group, they found some evidence of population structure among five population segments. These five distinct population segments could be considered for listing, but with no clear evidence suggesting relationships among these disjunct populations, they recommend that more research using other molecular markers be conducted to provide a measure of genetic connectivity capable of revealing more detailed taxonomic and population level structure for identifying potential conservation units.

Regardless of federal ruling, the overall rarity of Massasaugas in south Texas and their geographic isolation from other populations in the Western-Desert Massassauga group means that they deserve continued attention. The researchers recommend continued survey efforts in this region to provide information on the distribution and abundance of this Massasauga population and to monitor changes to its habitat over time.

Ryberg, W.A., A. Blick, J.A. Harvey, T.J. Hibbitts, and G. Voelker.  2013.  Genetic determination of the Desert Massassauga distribution in Texas.  State Wildlife Grant Report to Texas Parks and Wildlife Department.