I downloaded an app recently that is absolutely addicting. While you’re out and about, you can find a wide variety of creatures, and after capturing them with your phone, you learn their name, some information about them, and they’re added to a list of all the creatures you’ve found so far! I’ve gotten so hooked on adding to my collection that I find myself going out and about more often, always with my phone in hand.
I’m describing Pokémon GO, right? Nope. I’m talking about iNaturalist.
To be clear, I love Pokémon GO. I go out to play whenever I can, I’ve redesigned my main walking route to maximize the Pokéstops I visit, and I get wildly excited whenever I see a Pokémon I haven’t caught yet. I’ve been playing Pokémon games for the last 11 years, and I am captivated by the thrill of discovering new Pokémon and filling out the Pokédex. And I think it’s that same sense of discovery that has me hooked on iNaturalist.
In Pokémon GO, you find fantastic virtual creatures hidden all around you. But we are all surrounded by fantastic real creatures, too. In Pokémon, once you capture a Pokémon for the first time, it is automatically identified and added to the Pokédex, but I’ve never had a tool like that for real animals and plants. That’s where iNaturalist comes in.
The app, available for iOS and Android, lets you snap a picture of a plant or animal with your phone and upload it, and automatically adds where and when you saw it. There’s a community of naturalists on there that can help provide an ID, which is relayed to the app. But the app is just the tip of the iceberg. The website iNaturalist.org is where the real powerhouse is, where you can peruse other observations, learn about identification skills, or read more about the critters you just observed. Any of iNaturalist’s 200,000 users can see your observation and try to provide an identification for it. Or if you already know about the plants or animals, you can even ID it yourself! Just know that it’s a bird? That’s good enough to attract the online birders to help you out! iNaturalist then keeps track of the number of different species you’ve observed that have been identified, just like the Pokédex. There are even leader boards and annual contests.
Though my Pokédex is complete once I’ve caught 150 Pokémon in Pokémon GO, I’m limited on iNaturalist only by what I can find. This summer, I’ve caught 60 Pokémon, but I’ve added more than 100 observations on iNaturalist. There have been 46,633 species observed on iNaturalist worldwide, and that number is still growing! I think that’s really exciting!
But I’ve left out one of the coolest parts. In Pokémon, you fill out the Pokédex at the request of a Pokémon professor to help them with their research. Well, iNaturalist helps real scientists! Once there’s a consensus for the species ID of your observation, it can be marked as “research grade,” meaning biologists and naturalists can use the data from your observation in studies looking at distribution and population health of a certain species!
If you like Pokemon GO, and you like nature, you will love iNaturalist. You’ll be amazed at the discoveries you can make and the real world critters you can find!
The large springs of the Balcones Escarpment (Comal Springs in New Braunfels or San Marcos Springs, for example) are well known for their crystal clear water, but a visit to these special places provides little hint of the biological complexity farther underground.
The springs are fed by the Edwards Aquifer: home to a globally significant assemblage of strange, and poorly known species, most of which occur nowhere else on Earth. Few people have ever seen eyeless salamanders with toothpick thin legs, blind catfish (one species with teeth and one without), and a suite of invertebrates including transparent snails, a blind leach, albino beetles, and dozens of species of shrimp-like crustaceans (including actual shrimp).
In the darkness below our feet, photosynthesis, which provides the fuel for most life on Earth, cannot occur, and no green thing grows. In the absence of photosynthesis, what sustains the Edwards Aquifer underground menagerie? In an article just published in Ecology, a multidisciplinary team of researchers from Texas Parks and Wildlife, Texas State University – San Marcos, and the University of Tennessee – Knoxville provides some answers, and their findings go far beyond simply identifying what’s on the menu for obscure aquatic species.
In the late 1970’s, the world was thrilled when researchers using submersible vessels discovered deep-sea hydrothermal vents where bizarre tube worms, clams, shrimp, and a host of other species thrived in great numbers, just on the edge between the dark, freezing abyssal plain and the scalding, geothermal slurry pouring from deep within the Earth. The key to this ecosystem, was the sharp chemical gradient between those two, very different waters. The geothermal vent water is laden with chemicals such as methane and sulfide. Where these compounds come into contact with the oxygen-rich water of the deep ocean, chemical reactions occur, and these chemical reactions produce energy. Since the earliest days of life, microbes have been able to harness energy from these reactions just like plants harness energy from the sun to build organic compounds and fuel metabolic processes. In turn, those microbial communities can be consumed (or even co-opted as symbionts) by higher-level taxa. Voila! An ecosystem is born.
In the Edwards Aquifer of Central Texas, geologists and hydrologists have long known that not all water is created equal. Along the southern and eastern boundary of the aquifer, deliciously drinkable fresh water is rapidly replaced by anoxic, saline waters laden with some of the same chemical constituents found in hydrothermal vent waters (including sulfide and methane). Although not as hot, violent, or awe-inspiring as black smokers of the deep sea, this transition zone, referred to as the ‘bad water line’, supports microbial communities capable of the same, light-free carbon fixation (a process known as chemolithoautotrophy). Whether this process is important as a food source for the animals in the aquifer was one of the principal questions investigated in the new article.
Certainly, it is not the only potential food source. Along the northern and western boundary of the aquifer, surface streams loose water to the aquifer, helping to maintain spring flow, but also transporting organic matter from the surface, including plant material, algae, and even the occasional animal carcass. In many subterranean environments, this organic matter transported from the surface is the sole-energy source. In the Edwards Aquifer however, the researchers noticed an unusual pattern: the number of species present in the aquifer was greatest near the bad water line, and decreased closer to those surface streams. If these aquatic species were dependent on that surface input, why weren’t they clustered around the source?
To help answer the question, the researchers employed a technique called stable isotope analysis. At the atomic level, organic matter produced from photosynthesis looks very different than food produced via chemolithoautotrophy. Furthermore, in the case of stable isotope analysis, the old adage ‘you are what you eat’ holds true, and whether an animal is eating plant material (or other animals that were once eating plant material) or chemolithoautotrophic microbes can be revealed through the distinct atomic signature that these different food sources leave behind in the tissues of consumers. When the researchers looked at animals and organic matter from throughout the aquifer, they found the telltale signature of microbial production, particularly in food webs near the bad water line. In animals near recharge features, the photosynthetic signature was more prevalent. The researchers concluded that both photosynthetic organic matter and microbial organic matter produced at the bad water line via chemolithoautotrophy were present in the aquifer and consumed by animals, but that the importance of each to a given animal varied depending on the animal’s location within the aquifer.
The presence of two distinct food resources in the aquifer has several important impacts on the groundwater community. Looking at the specific shapes of mouthparts for several crustacean species, the researchers found evidence that some animals behaved as filter feeders, using mouthparts with long, feather-like hairs to filter organic matter from the water (like a baleen whale), while other species were scraping organic matter off of conduit walls in the aquifer. Interestingly, the filter-feeders exhibited a stronger photosynthetic signal while the scrapers showed a stronger chemolithoautotrophic signal, perhaps because the filter feeders where utilizing organic matter from the surface that was being washed through the aquifer while the scrapers were utilizing microbes growing on the walls of the aquifer. The researchers also found strong evidence of multiple food chain levels, with herbivores, predators, and predators of predators. The presence of high-level predators and animals using specialized feeding behaviors is unusual and largely unreported from underground habitats where most species are adapted to eat whatever they can find, whenever they can find it. Specialized feeding strategies are only expected where food supply is relatively constant.
Many of the species present in the aquifer, represent ancient lineages derived from marine ancestors that colonized millions of years ago. The long-term survival of those species can also be explained by chemolithoautotrophic microbes, although the researchers emphasize that such a scenario is only a hypothesis. Geologic, archeologic, and paleo-botanic evidence all point to multiple periods of extreme aridity in Texas’ past. During those times, plant production on the surface would decrease, as would the amount of surface water recharging the aquifer. Consequently, the input of plant material from the surface would also decrease. Microbial production in the aquifer, however, would continue, largely unaffected by surface aridity, allowing the deep parts of the aquifer to serve as a refuge for populations during the lean times.
This new research on the Edwards Aquifer food web has important implications not only for the conservation of Edwards Aquifer species, but also for our understanding of groundwater habitats around the world. The researchers note that chemolithoautotrophy may be much more important and more widespread than is currently understood. In the Edwards Aquifer, the presence of a dependable food source may help buffer species from natural and man-made changes to recharge and surface-derived food inputs. However, continued groundwater extraction and a growing interest in desalinization of groundwater from near the bad water line may have unpredictable impacts on microbial production. For over a century, the Edwards Aquifer has intrigued biologists, and there is no doubt that additional surprises will emerge as researchers continue to shed light on its dark secrets.
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.
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.
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.
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.
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.
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.
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.
For the last two weeks, we have been working through the world’s 11 orders of living arachnids, all of which occur in Texas, the only U.S. state with such arachnid diversity. From common garden spiders to enigmatic microwhipscorpions, we’ve seen that these arachnids have a variety of unusual forms. However, we have to yet to be introduced to two of Texas’ most elusive arachnid orders, found in the Lower Rio Grande Valley.
The short-tailed whipscorpions (Schizomida) appear similar to vinegaroons and micro-whipscorpions, but lack a long “tail” or a “pipe cleaner”. These ant-sized arachnids are typically found, like micro-whipscorpions, in leaf litter or under rocks and logs. Aside from a single record of an undescribed species in Val Verde County, Texas short-tailed whipscorpions have only been recorded from near Edinburg and Rio Grande City. Most short-tailed whipscorpions are found in tropical regions around the world, and a few scattered records exist from southern states and as far north as Sequoia National Park in California.
So far, we’ve covered 10 orders, which means that we’ve come to the end at last. So what’s our 11th and final order that sets Texas apart from all other states? The hooded tick spiders (Ricinulei) are the smallest order of arachnids and they look a bit like a fuzzy tick with no head. Of course, they do have a head, but the mouthparts are hidden by a strange plate that hangs down where you would expect a face (hence the name ‘hooded’). Like its cousins, the hooded tick spider is found in leaf litter and soil and under rocks and wood.
Because these strange animals are primarily tropical, you might expect the U.S. to be out of luck for hooded tick spiders. But wait! In 1939 a single species was described from Edinburg, Texas, representing the only hooded tick spider known from the United States. But don’t think that finding one is as easy as a trip to Edinburg. “The curious, enigmatic arachnids of the Order Ricinulei are regarded as the rarest of all arthropods.” So begins the description of our Texas species, which also happens to be one of the smallest, at about 1/8 inch in length. Not only are these creatures rare, the original sampling location for Texas’ hooded tick spider, Pseudocellus dorothae, has been destroyed by urban development, and to my knowledge, the species hasn’t been seen since, meaning that if you find one, you’ll be the first person to do so in three-quarters of a century (if you see one, take a picture and please let us know!).
And with the hooded tick spider, the Texas Arachno-Challenge comes to an end. It will take you from woodlands of east Texas to the semi-tropical Lower Rio Grande Valley and west to the deserts of the Trans-Pecos. You’ll see tiny pseudoscoropions and giant vinegaroons, and if you succeed, you’ll be a true explorer of Texas biodiversity.
Last week, we learned that all 11 of the world’s arachnid orders can be found without ever leaving the boundaries of Texas. We were introduced to several of the more common orders, but left off heading to the Trans-Pecos for some of the largest of Texas’ arachnids.
Most people that live in central and west Texas, are familiar with vinegaroons (Thelyphonida). Our one species, which also occurs in other southwestern states and large parts of Mexico, can grow over three inches in length with a formidable looking pair of pinchers (technically called chelicerae) and a whip-like tail. Generally harmless, they can pinch and excrete acetic acid (a major component of vinegar, hence the name). Vinegaroons burrow under rocks and are active at night.
While you’re out taking a night hike looking for vinegaroons, keep an eye out for what, at first glance, looks like a medium to large size spider, quickly scurrying about, searching for prey on open ground or under the desert bushes. On closer inspection, windscorpions (Solifugae), also known as camel spiders or sun spiders, can easily be distinguished from true spiders by their segmented abdomen, disconcertingly large, paired mandibles (again, chelicerae), and what appears to be five pairs of legs (the 5th pair are actually modified mouthparts called pedipalps). Windscorpions occur throughout most of the western United States.
Less common in the U.S., our eighth order, (Amblypygi) can be very abundant in the tropics, but are rarely encountered in Florida and Southwestern states including Texas. Like a flat, segmented spider, tailless whipscorpions look formidable with huge mandibles and creepishly long legs (particularly the 2nd pair that are used like antennas). However, if you are lucky enough to find one, your biggest challenge will be snapping a picture before it scuttles off at rapid speed. The single species in Texas, Phyrnus operculatus, has been recorded from the Big Bend region and a few caves in the southwestern edge of the Edwards Plateaus. Look under tree bark (where you can find a tree) and under stones, particularly in areas with large boulders and extensive limestone exposures that provide crackes and crevices in which the quarter-sized tailless whipscoprion can hide.
Perhaps the strangest of the arachnids, the microwhipscorpions (Palpigradi) are also rarely seen. In fact, of the 11 arachnid orders, this is the only one still on the bucket list for yours truly. In appearance, a microwhipscorpion looks a bit like a tiny, eyeless vinegaroon that has had its ‘tail’ replaced by… a pipe cleaner. Like I said, they’re strange.
In Texas, species have been described from northeast Texas, near the Red River and from Austin, Texas. Like the pseudoscorpions, these tiny animals, though visible with the naked eye, will probably require magnification to locate. They have been recorded from under stones, in association with silverfish. Though you may be able to locate one by visually searching, there are also numerous contraptions that you can build to extract tiny animals from soil samples (I’m busy building one now to check off that bucket list). Although microwhipscorpions probably occur through much of the U.S., there is very little data on these enigmatic creatures.
Our final two orders will require travel to the Lower Rio Grande Valley, and they’ll be your biggest challenges. But to find out what they are, you’ll have to wait until next week, for the Texas Arachno-Challenge III.