New Management Protocols for Texas Landowners to Support Native Pollinators

Interest in the conservation and perpetuation of native bees and other native insect pollinators has grown rapidly over the last few years. Several native insects that visit flowers, including some bumble bee species and the monarch butterfly, have experienced dramatic population declines and are in need of conservation action. In addition, significant challenges to managed European honey bee health has sparked interest in native insects as alternative pollinators for agricultural production.

As more than 95% of Texas lands are privately owned, effective native insect pollinator conservation will require private landowner engagement and involvement. Landowners can play a significant role in conserving and maintaining populations of native ins
ect pollinators by applying management practices that benefit these species. However, large-scale conservation is often cost-prohibitive without financial incentive. One such incentive, available to landowners who currently manage land qualified under the 1-D-1 Agricultural Tax Valuation, is Agricultural Tax Appraisal Based on Wildlife Management Use.
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The Nongame and Rare Species Program at Texas Parks and Wildlife Department has developed management guidelines for native insect pollinators landowners can use to develop wildlife management plan’s for their properties. These guidelines outline potential actions from prescribed burning, native plant re-seeding, installation of native pollinator plots, to creating nest sites; practices that could be applied to small or large acreages.

This new publication, Management Recommendations for Native Insect Pollinators in Texas, is now available online.

Landowners who apply these practices to their lands will be supporting populations of native pollinators that aid in maintaining healthy plant communities on their properties as well as those lands that surround them, which benefits a range of other wildlife. In addition, landowners will be conserving and perpetuating native pollinators that can provide pollination service to surrounding agricultural producers, potentially reducing the need for leased honey bee hives to pollinate some crops.

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Native solitary bee. Courtesy of Jessica Womack.

Why Pollinators and Pollination Matters
Pollination is one of the most vital processes sustaining natural ecosystems and agricultural production.  The majority of flowering plants that comprise Texas’ diverse ecosystems rely upon animals, mainly insects, to transport pollen among flowers to facilitate pollination and ensure the production of viable seed. Viable seed is critical for the perpetuation of plant species across the landscape. As with native flowering plants, many plants in agricultural production are reliant upon insects for pollination to set fruit and produce seed. The annual value of insect-pollinated crops to the U.S. economy is estimated at over $15 billion (The Economic Value of Ecological Services Provided by Insects).

Although the non-native European honeybee tends to garner the most public attention, there are actually several hundred bee species that are native to Texas.  These include bumble bees, carpenter bees, mason bee, leafcutter bees, longhorned bees, and many others. These native bee species were here long before the honeybee and are critical to the state’s diverse native plant communities as well as agricultural production.

Why Bees are Efficient and Effective Pollinators
Of all the insects that visit flowers in Texas, from beetles, butterflies, moths, and wasps, bees tend to be the most efficient and effective pollinators.  Two traits make bees preeminent pollinators.  First, they purposefully collect pollen to feed their offspring.  The act of foraging for this protein-rich food source results in the transfer of pollen from flower to flower.  During a single day, a female bee may visit several hundred flowers, depositing pollen all along the way.  Second, bees tend to be specific about the flowers they visit.  During a foraging trip, a female bee may only visit the flowers of a particular plant species.  The benefit of such foraging preferences is that the plants’ pollen is not deposited on the flowers of a different plant species and wasted.

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Leafcutter bee carrying a load of pollen. Courtesy of Eric Isley.

Native bee pollination is critical to the maintenance of Texas’ diverse ecosystems.
Many of the berries, nuts, and seeds consumed by birds, mammals, and other insects are the result of bee pollination of native woody and herbaceous plants.  Along with their substantial ecological contributions, native bees have proven to be more efficient and effective pollinators of several agricultural crops than honey bees.  Several crops, including blueberries, grapes, olives, peanuts, pumpkins, squash strawberries, and tomatoes are more effectively pollinated by native bees than the non-native honey bee. The added benefit to farmers from native bees is that their services are essentially free if adequate natural to semi-natural habitat is maintained around farm fields to support healthy populations of these pollinators.  The pollination service provided to U.S. agriculture by native bees has been estimated in excess of $3 billion annually.

For additional information, please contact Michael Warriner, Nongame and Rare Species Program Leader at michael.warriner@tpwd.texas.gov.

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.

Science with a Sledgehammer

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TPWD biologist Benjamin Hutchins hammers part of a Bou-Rouch pump into cobbles on the Frio River.

Flip over a rock in a stream and you may reveal some interesting aquatic invertebrates. Dig deeper into the gravel below and adjacent to the stream and you may find groundwater organisms more akin to cave-adapted species than stream dwellers. This habitat, called the hyporheic zone, is a transition between surface water and deeper groundwater. It can contain rare and unusual, blind and albino organisms like those found in springs, wells, and caves. However, because of its’ inaccessibility, little is known about the habitat or the organisms found there. Sampling requires hammering a metal spike several feet into the cobbles. This spike is hollow and perforated at the bottom. When a hand pump is mounted to the spike, water, and the organisms that live in it, can be pumped out. Although biologists have been using this instrument, called a Bou-Rouch pump, in Europe for decades, research in the United States and most other countries has been rare. In Texas, the hyporheic zone has only been sampled a handful of times, in a handful of places. Even with this limited-effort, biologists have collected rare and undescribed groundwater organisms.

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TPWD biologist Benjamin Hutchins and researcher Aaron Swink, from the Edwards Aquifer Research and Data Center at Texas State University, pump hyporheic water from the Frio River to measure water chemistry and sample for rare invertebrates.

For the first time, biologists from Texas Parks and Wildlife and Texas State University are taking a closer look at this habitat in Texas. In addition to surveying the organisms present, biologists are also measuring a suite of physical and chemical parameters to better characterize the habitat. It may turn out that some of the residents of the hyporheic zone are not as rare as previously thought: just that no one has looked closely for them. These organisms may also reveal important information about the health of our beautiful Texas springs. Because this research is just beginning, it is far too early to make any conclusions, but keep an eye on Frontiers in Texas Biodiversity for future updates.

First Comprehensive Survey of Monahans Sandhills Endemic Insects

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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.

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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.