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.

Freshwater Turtles: Misconceptions and Commercial Collection

Texas map turtle, Colorado River, Travis County, Texas (Cullen Hanks).
Texas map turtle, Colorado River, Travis County, Texas (Cullen Hanks).

Freshwater turtles are a conspicuous component of freshwater ecosystems in Texas. Habitat loss and degradation, competition with non-native species, commercial collection (currently legal for only four freshwater turtle species in Texas), depredation by landowners and fishermen, and vehicle mortality represent significant threats to turtle populations.  Some of these threats are not unique to turtles and, in fact, apply to many species.

Misconceptions

Other threats are the result of misconceptions about the role of freshwater turtles in natural environments and a consequential undervaluing of these reptiles as components of healthy ecosystems.  This prejudice, in turn, has paved the way for indiscriminate culling and collection of turtles across Texas.  Turtles are particularly susceptible to decline due to their slow growth rates and low survivorship to adulthood.  In addition, large female turtles are responsible for the majority contribution to annual reproduction yet typically make up only a small percentage of wild populations and are disproportionately impacted by commercial harvest and road mortality.  Turtle populations may take decades to recover from declines.

Many landowners and fishermen express dislike for turtles because of the perceived notion that they prey on- or compete with- game fish, including largemouth bass and catfish.  In fact, freshwater turtles are primarily omnivorous with a majority of their diet composed of aquatic plants, mollusks, and crustaceans.  Even notorious carnivores such as softshell turtles and the common snapping turtle primarily feed on vegetation and invertebrates, along with some carrion.

Red-eared slider, Estero Llano Grande State Park, Hidalgo County, Texas (Cullen Hanks).
Red-eared slider, Estero Llano Grande State Park, Hidalgo County, Texas (Cullen Hanks).

Species such as the red-eared slider and Texas river cooter are more carnivorous as juveniles but transition to a largely vegetarian diet by the time they reach a few inches in length (Dreslik 1999).  Fish, even small species such as minnows, make up a relatively small part of their diet.  Turtles are often blamed for eating fish and stealing from trotlines but this is due largely to the fact that turtles do not discriminate between carrion on a hook or floating freely.

Disdain for turtles has often led landowners to trap or shoot turtles in private ponds in the hope that removing turtles would aid fish populations.  Recent research has documented the important role turtles play in the structure and stability of aquatic food webs and ecosystem processes (Aresco 2009).  Indeed, turtles may improve fishing conditions by helping to break down organic material (thus, freeing it up for consumption by aquatic invertebrates which become prey for turtles and fish alike) and consuming aquatic vegetation (Lindsay 2013).

Commercial Collection

Variety of turtles for sale in Chinese market (Vmenkov).
Variety of turtles for sale in Chinese market (Vmenkov).

The impact of commercial harvest on global turtle populations has been well-documented and represents a significant threat to the survival of many turtle species (Gibbons et al. 2000, Mali 2014).  Steep population declines and extirpations of many Asian turtle species due to harvest pressures have led to increased export of turtle species from the United States to meet market demands.  Slow growth rate, long generation time, and targeting of large, breeding age females for collection make turtles particularly susceptible to harvest-related declines.

Regulations (Texas Turtle Regulations)  implemented by Texas Parks and Wildlife Department (TPWD) in 2007 limited commercial collection of freshwater turtles to four species (common snapping turtle, red-eared slider, smooth softshell and spiny softshell turtles) and prohibited all commercial collection from public waters. Some states (Alabama, Florida) have implemented statewide bans on commercial collection from both public and private waters due to concerns about the long-term conservation of their freshwater turtle species.

TPWD’s regulatory changes led to a decline in the number of turtles harvested, according to annual reports submitted to TPWD by nongame dealers.  A total of 5,430 turtles were reportedly harvested in 2007 (the last year in which widespread commercial collection was legal).  Annual harvest numbers have averaged 495 turtles per year since 2008. Although commercial turtle collection in Texas appears to have waned in recent years, demand for harvested turtles will continue to be influenced by global market demands.

While it appears that commercial take of freshwater turtles in Texas has decreased, it is unclear if this decrease is due to a decline in turtle numbers (and, therefore, availability), under-reporting of harvest, or a lull in commercial activity.  The U.S. Fish and Wildlife Service has announced a proposed rule (FWS-HQ-ES-2013-0052-0001) to address the growing threat of illegal take and trade in native turtles. If finalized, this action will bring three of Texas’ freshwater turtle species, the common snapping turtle, smooth softshell turtle, and spiny softshell turtle, under the protection of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and require exporters to obtain a permit before shipping turtles overseas.

Evaluation of the current state of freshwater turtle commercial collection in Texas will be a focus of the Nongame and Rare Species Program this year.  If you have any information you would like to share regarding this practice in the state, please email andy.gluesenkamp@tpwd.texas.gov.

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.

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.