Porcupines in Texas are Moving East

Have you seen a porcupine lately? If you live in central Texas, the chances are you’ve noticed one in a tree or on the road. If you haven’t seen one yet, keep your eyes out, because they’re expanding into new territory.

In the past few years, Texas Parks and Wildlife Department (TPWD) has been contacted by numerous people reporting porcupines in central Texas. Porcupines are known to occur primarily in northern and western Texas, but not so much in the central portion of the state. The map below shows the generally accepted distribution of porcupines in Texas.

Previously known range of porcupines in Texas. From "The Mammals of Texas - Online Edition".
Previously known range of porcupines in Texas. From “The Mammals of Texas – Online Edition”.

While receiving all these porcupine reports was interesting, they were also anecdotal and difficult to interpret. However, now a new tool called iNaturalist has enabled members of the public to record and share wildlife observations. iNaturalist uses photos, GPS locations, and community identifications to improve the reliability of the data and it is quickly becoming a powerful tool for biologists and researchers to learn about wildlife from the public.

Currently, iNaturalist has 73 porcupine reports for Texas since 2012. The map of these observations supports the reports we received from the public. While we shouldn’t confuse an abundance of observations with the abundance of porcupines (the number of observations is also influenced by the number of people making observations), these data clearly demonstrate a shift in our understanding of the distribution of porcupines in Texas.

Texas porcupine observations in iNaturalist from 2012 – 2015.
Porcupine observations in iNaturalist from 2012 – 2015.

It’s exciting to see how much we can learn in a few short years when people combine their efforts and share their knowledge. Check out the Mammals of Texas iNaturalist Project to start learning about other mammals in the state.

So keep your eyes peeled for porcupines! They are fascinating animals and if you live in Austin or San Antonio, they may be headed your way.

Science with a Sledgehammer

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.

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.

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.