6:00pm - While walking through bottomland forest, a Texas rat snake (Pantherophis obsoletus), 6 ft. 4 in. male, moving along a fallen log. At the same time, choruses of Green treefrogs (Hyla cinerea) at call index 2, as well as Cricket frogs (Acris crepitans) at CI 3, and S. leopard frogs (Lithobates sphenocephalus utricularius) at CI 1. As we walked to the edge of the marsh, we observed a Great blue
Texas Field Notes k A j our na l o f w i ld l if e a n d w il d p l a c es i n Texa s k
October, 2018 Volume 9, No. 2
Inside This Issue Editorial …………………..
2
The Oasis at the Bottom of Texas……………………… 3 Up Against the Wall: Three Species Vie for Survival in the Rio Grande Floodplain..
18
Trinity River Turtle Survey …. 22 Bucket List Places
Sabal Palm Sanctuary
29
Texas Field Notes
October, 2018
Texas Field Notes Vol. 9 No. 2 Texas Field Notes is a quarterly ejournal of the wildlife and wild places of Texas, available for download from greatrattlesnakehwy.com and from https://issuu.com/texasfieldnotes. The purpose of Texas Field Notes is to explore the natural history of Texas, connect people with nature, and share what that connection looks like. Editor: Michael Smith Design & Layout: Michael Smith All photos taken by authors except as noted otherwise
Advisors Rob Denkhaus
Fort Worth Nature Center & Refuge
Travis LaDuc
Editorial: An Increased Affinity for Natural Places And Turtles! Michael Smith What is the purpose of Texas Field Notes? These stories of Texas natural regions and wildlife are, we hope, interesting and educational, with some nice images making it easier to see what we are talking about. But the “higher calling” of this publication is to leave readers with a greater affinity for Texas’ natural places and
University of Texas at Austin
to take note of things that threaten them so that we can consider what we might
Ann Mayo
do to protect wildlife and habitat. A couple of articles in this issue touch on
Weatherford College
Jesse Meik
Tarleton State University
Suzanne Tuttle
(Retired) Fort Worth Nature Center & Refuge
Marianna T. Wright
National Butterfly Center Our advisors provide valued input and assistance, but responsibility for the content of articles remains with the authors.
threats to natural places a little more directly than usual. Several preserves in the Lower Rio Grande Valley have been in the news because, if a border wall is built through that region, they will be partly or completely cut off from the rest of the U.S. In this issue, I have written about a couple of trips to the Valley (“The Oasis at the Bottom of Texas”) and Marianna Treviño Wright has described how destructive the planned wall would be to the habitat and wildlife of the area (“Up Against the Wall: Three Species Vie for Survival in the Rio Grande Floodplain”). We hope that these articles convey a little of what is at stake in the Valley, and that you will support the refuges, preserves, and sanctuaries
Our website and blog is: The Great Rattlesnake Highway www.greatrattlesnakehwy.com which contains information about Texas’ ecoregions and articles that do not appear in Texas Field Notes. © 2018 All rights reserved, except that ownership of photographs and articles remains with the contributor.
however you can. This issue also includes an article from Andrew Brinker that describes a turtle survey conducted in Fort Worth with the involvement of his students from Paschal High School (“Trinity River Turtle Survey”). Great data, great photos, and great training and inspiration for a new generation of herpetologists and conservationists!
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Volume 9, No. 2
The Oasis at the Bottom of Texas Michael Smith
Laguna Atascosa National Wildlife Refuge The Rio Grande comes down from New Mexico and, when it reaches El Paso, traces the border between the U.S. and Mexico down around the Big Bend and southeastward until it reaches the Gulf of Mexico. Along much of that border route it cuts through desert on both the Mexican and U.S. sides. The landscape is Chihuahuan Desert, shading into the Tamaulipan Mezquital which continues the desert theme in plant communities dominated by honey mesquite. At least in part due to a history of poor land management, the South Texas Plains often are comprised of thorny thickets – the “thorn scrub.” However, the last stretch of the Rio Grande as it approaches the Gulf is a subtropical oasis. The Lower Rio Grande Valley (LRGV) is generally considered to include four Texas counties: Starr, Hidalgo, Willacy, and Cameron counties. It is really a floodplain rather than a valley, and the river meanders in twists and turns, creating oxbow lakes or resacas. Along the river there are scrubby woodlands of mesquite, Texas ebony, guajillo, and other plants, culminating in a handful of sabal palm woodlands south of Brownsville. Wildlife includes the ocelot, birds such as the green jay, great kiskadee, and a variety of reptiles and amphibians such as the Texas indigo snake, speckled racer, northern cat-eyed snake, Berlandier’s tortoise, the Rio Grande lesser siren, the sheep frog, and Mexican burrowing toad. These plant and animal communities have to live alongside a huge and growing connected series of cities, including Brownsville, Harlingen, McAllen, Edinburgh, Mission, and others. Collectively, nearly a million and a half people live and work there.1 Surrounding the cities, floodplain habitat has been converted to agricultural fields where numerous crops are grown. How does anything like the original ecosystems, with ocelots, indigo Page !3
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The Oasis at the Bottom of Texas (continued) snakes, and sabal palms, continue to survive? Much of their survival can be credited to the series of preserves, state parks, nature centers, and the various places protected within the Lower Rio Grande Valley National Wildlife Refuge. Many of these places are situated on the Rio Grande, and the chain of public and private protected lands works as a wildlife corridor, according to Marianna Treviño-Wright, the Executive Director of the National Butterfly Center (NBC). In addition to the pressures on wildlife from all those people and cities, we can add the border fence and proposed border wall as threats. A healthy population of a species of animal depends on a large enough area of suitable habitat so that individuals can move about with shifting conditions of rainfall and vegetation. The species’ health also depends on a large enough pool of breeding individuals so that there is limited inbreeding, which (over generations) weakens the genetic health of the population. These conditions cannot be met when populations are confined in small and fragmented patches of habitat. And if the border wall, including tall concrete barriers, is built, wildlife may be trapped and drown during periodic floods. It’s a tough time to be an ocelot in the LRGV! In an article in press at the journal Bioscience, a distinguished group that includes Paul Ehrlich and Edward O. Wilson outline three ways in which the border wall threatens biodiversity.2 The fact that the rate of undocumented migration by Mexicans is dropping adds a note of irony to the proposed wall.3 It is in the context of all the threats faced by the plant and animal communities of the LRGV that Clint King and I have traveled there a couple of times over the past year. We wanted to see some of these places like the Santa Ana National Wildlife Refuge, or the National Butterfly Center, while we still could. Clint has visited the Valley on several earlier occasions, and I was with him for two of those trips as well. I describe visits to several of the preserves below, in the hope that you will want to go see them for yourself, and then speak up and help protect these places. La Sal Del Rey The northernmost places within the Lower Rio Grande Valley National Wildlife Refuge (NWR) are in Hidalgo and Willacy Counties, west of the town of Raymondville.4 There you will find a couple of hypersaline lakes, La Sal Vieja (“The Old Salt”) and La Sal Del Rey (“The King’s Salt”). The lakes sit on top of huge salt deposits, making them much saltier than ocean water. The surrounding land contains thick thorn scrub with patches of grassland, and the trails on the refuge properties offer a chance to walk through mesquite and prickly pear thickets, with tepeguaje, Texas ebony, and other trees and shrubs adding to the plant diversity. Clint and I first visited La Sal Del Rey in 2009, and the hike from the car to the lake gave us our first introduction to the triangle cactus (also called the barbed wire cactus), with long stems roughly the size of “pool noodles” sprawling out from its base. They are deeply ribbed, with long spines coming from the areoles along the edges of those ribs. On that same walk, we were confident we could leave the water in the car; by the time we returned, we were getting seriously dehydrated and overheated and in our mental fog we just made ourselves put one foot in front of the other until we made it to the car. Always take water on south Texas hikes! Our visits to these places last October were much more comfortable. The trail toward La Sal Vieja was an invertebrate paradise, finding a number of Buprestid beetles Clint had not seen before in the field, as well as a Page !4
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The Oasis at the Bottom of Texas (continued)
“Halloween Punk Rock Pinhead Assassin Bug,” aka unidentified assassin bug instar
cardinal jumping spider which mimics the velvet ant in its somewhat “furry” black-and-red appearance. We also found what was probably an instar (a subadult developmental phase) of an assassin bug that Clint dubbed the “Halloween punk rock pinhead assassin bug” based on its colors and spikey appearance. At La Sal Del Rey, I walked up on the observation deck to see the broad salt flats shading into the lake, with a large group of sandpipers milling around at the water’s edge. It was like a glimpse of the beach in microcosm, only the water was undisturbed by any wave or
movement. The birds were poking in the sand for the insects and aquatic invertebrates that are their prey. I approached, and at one point they spooked, briefly flying in a tightly coordinated group, quickly returning to the wet sand to continue their activity. Walking out over the salt-crusted sand and silt toward the water, my footsteps crunched here and there on glittering deposits of salt. I approached the sandpipers, which shuffled about nervously but did not fly away. Several of their group hopped about on one leg, like little one-legged pirates. My reaction to the first bird that did this was a concern that it had lost a leg and was forced to hobble about with his brethren. Then I saw that it appeared to be a habit among numerous members of this troupe, and I was less concerned. Walking back from the bare salt flats into scattered vegetation, I wondered what could live in the salty, bare sand, in many places
Sandpipers at La Sal Del Rey Page !5
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October, 2018
The Oasis at the Bottom of Texas (continued) under a brittle glaze of salt. One of the principal plants appears to be a saltwort, with succulent little fingerlike leaves, pale green or bluegreen toward the top but pinkish toward the base. On the way back, I spotted a kind of argiope spider sitting in its web constructed in a clump of prickly pear cactus. Clint identified it as a silver argiope, a more southern
Silver Argiope
resident that barely crosses into the United States. It has the basic garden spider form, but its abdomen has some projections that were fairly subtle in this young one that Clint says become more pronounced in adults. We did see a couple of whiptail lizards, and the second, tiny one reminded us that the year’s eggs had fairly recently hatched. We saw lizard scat, suggesting that there were many other lizards we did not get a chance to see. One plant on the trail, a Baccharis (also known as “seep willow,” “poverty weed,” and several other names) was visited by an amazing number of insects. The most exciting was a pair of Trachyderes mandibularis (the “long-jawed longhorn beetle”), a beetle whose antennae segments alternate between black and orange, to match the colors of its wing covers or elytra. We drove the caliche roads around La Sal Del Rey, finding a feisty little Dekay’s brownsnake and a Texas tan tarantula. The most memorable finds, however, were a series of big western diamond-backed rattlesnakes. South Texas is known for large specimens of this snake, maybe because the climate allows nearly year-round
Western Diamond-backed Rattlesnake near La Sal Del Rey
Page !6
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The Oasis at the Bottom of Texas (continued) activity and growth. These snakes were consistently easygoing, and of course we treated them with respect, taking no chances with such big pit-vipers capable of delivering a big dose of potent venom. Approaching them with deliberate movements and no “showboating” probably helped insure that they were easygoing. The National Butterfly Center Forty or fifty miles southwest of La Sal Del Rey, on the banks of the Rio Grande, is the National Butterfly Center. When you first arrive at the Center, you see a quiet pool with lotus and other plants, and then walk to the visitor center entrance through patches of flowers alive with bees and butterflies. In my visit on October 18 of last year, these plants were heavily visited by queen butterflies (among many others), creating a kaleidoscope of black-edged orange wings with a sprinkling of white spots. But amid the peace and beauty of the center’s gardens looms a threat to the center’s integrity, as well as a threat to our system of fairness and due process. Clint and I were there to learn about the beauty of the place, the work of the center staff, as well as the threat that the property will be torn apart by a border wall. The Center’s director, Marianna Treviño Wright, was very generous, taking us on a walking tour of the 30 acres at the front of the center and then a tour of the 70 additional acres of habitat behind a canal and levee that currently can be driven or walked over. Knowing our interest in reptiles and amphibians, she first took us down a trail where an indigo snake periodically turns up. While we did not see the indigo, we did find a Mesoamerican cane toad hunkered down in a big lump on top of a cut tree stump, several feet off the ground. Wright said that they climb, and here was a clear demonstration of that! The cane toad is found in Central America and the Mexican coasts, making it barely into the United States along several counties of the lower Rio Grande Valley. It is our biggest toad, growing to roughly four to six inches long. Unfortunately, the species has been introduced in several spots around the world and is a harmful invasive in those areas. Wright showed us the canal and levee that divides the front and back of the property. The North American Butterfly Association (NABA), which is the parent organization to the Center, owns the land that the levee is on, but the government has an easement at the levee for flood control. The easement would allow government officials or contractors to enter the land and use it for specified purposes. While the language about the purpose of the easement may not say “border wall,” the government can describe the wall as a “fence” and assert that it is an improvement to the levee, thereby attempting to stay within
Mesoamerican Cane Toad Page !7
the purposes of the easement.
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October, 2018
The Oasis at the Bottom of Texas (continued) On the other side of the levee, the Center’s property is mostly a combination of forest and the kinds of plants that make up the south Texas thorn scrub. The low mesquites, acacias, and other trees shelter cacti and various shrubs that can support a variety of wildlife. A little over a mile down the road, we emerged at the banks of the Rio Grande, in this spot looking wide and grand, indeed. The possibilities for supporting wildlife and providing education and research opportunities are clear. The Center’s property is part of a conservation corridor that connects habitat up and down the river to support everything from indigo snakes to ocelots, Berlandier’s (Texas) tortoises to great kiskadees. Along with preserving a piece of the lower Rio Grande habitat, the Center is also busily helping schoolkids and others learn about wildlife. Wright said that they worked with 6,000 kids the previous year, and they are working with Streamable Learning to provide virtual field trips to classrooms anywhere and everywhere. Unfortunately, the border wall will significantly limit some possibilities and destroy others. In July of 2017, a government-contracted work crew showed up on the back property, with no notice and no communication to the Center, beginning to take earth samples and cutting trees and brush to widen an already wide dirt road. It is worth noting that this was not on the levee itself, where the government has the easement, but along a 1.2mile road owned by the Center running back to the Rio Grande. Customs and Border Protection (CBP) come onto the property at will, and occasionally things are tense. Appropriately, the end of the visit was not at all tense – it was pure lepidopteran coolness! Someone found a mercurial skipper visiting the butterfly gardens. This is a butterfly that makes use of lowland tropical forests from Argentina to south Texas but is not commonly seen here.5
Mercurial Skipper, at National Butterfly Center
It was also a new one for me, as I am a herper with a big interest in, but limited knowledge of, the whole natural world. I could have stayed and greatly expanded the variety of butterflies I have seen, as the Center’s website says it has the greatest number and variety of butterflies anywhere in the U.S.6 Page 8 !
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The Oasis at the Bottom of Texas (continued) Santa Ana National Wildlife Refuge A little further downstream along the river, in Hidalgo County south of the city of Alamo, is Santa Ana National Wildlife Refuge, 2,088 acres described as the “jewel of the National Wildlife Refuge System.” It has been at the center of the border wall issue, at least partly because it would be completely lost if the wall was built as planned. The levee along which the wall would be built crosses just below the entrance to the refuge, so that about all that would be left on our side of the wall would be the visitor center and the parking lot. A lot of local advocacy and the refuge’s status as a major birding destination surely played a role in the language of the spending bill earlier this year which states, “None of the funds provided in this or any other Act shall be obligated for construction of a border barrier in the Santa Ana Wildlife Refuge.”7 At least for now, there is a reprieve for the refuge. While exploring part of the refuge last October, we found that the rose-bellied lizard was very common in the refuge. In overall form they are like a small version of the familiar Texas spiny lizard, and in their skill at tree climbing they are as accomplished as their bigger cousins. I have memories of catching rose-bellied lizards as a
Rose-bellied Lizard
teenager in Corpus Christi, and I always associate them with mesquite branches several feet off the ground. The patterns of females are paler, while males sport light-edged dark spots on either side of the back, bordered by a light stripe. The other common lizard at Santa Ana NWR stays on the ground, often sunning on the trail and running off among the fallen branches and undergrowth off the trail. It is the Texas spotted whiptail lizard, and in
Texas Spotted Whiptail Lizard
last year’s visit, several of them Page !9
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The Oasis at the Bottom of Texas (continued) were busily hunting insects or sunning in the open, eight or ten feet ahead of us. The one I photographed on this day was a big male, the pinkish color under his chin and the blue-black patches of color on the belly scales just visible at the edges. Seven or eight light stripes run down the backs of these lizards, with rows of light spots between the stripes. Near a bird blind by one of the
Great Kiskadee
resacas, a big yellow and black bird flew in noisily. I did not know it as a great kiskadee at the time, but once you make their acquaintance, they are pretty easy to identify in subsequent encounters. From below its perch high in the tree, I could see lots of yellow, along with brown wing feathers and a black mask. It was also a bold and loud bird, though I did not really associate its shrieking, chattering call with “kiska-dee,” which it is supposed to resemble. The great kiskadee ranges through South America and
just barely into south Texas. It is a flycatcher that is described as behaving a little like a jay in its boldness. It eats insects, small animals, and fruit, and likes open woodlands near bodies of water.8 Another bird that is very familiar in the valley is the plain chachalaca. It is roughly chicken-sized, mostly a sort of gray-brown color with a buff-colored belly and whitetipped tail feathers, and we saw several groups of them at Santa Ana. They usually moved about on the ground and on low branches, and sometimes one would trot along in a way that reminded me a little of a big, chunky roadrunner. Like the roadrunner, their flight was often low and
Plain Chachalacas
for short distances. Chachalacas are a member of a mostly tropical family, making it as far north as the LRGV. Groups of them greet the dawn with choruses of “cha-cha-lac,” and they are described as equally at home on the ground or in the trees.9 Page !10
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A Sabal Palm
The Oasis at the Bottom of Texas (continued) Sabal Palms Sanctuary Following the Rio Grande a little over fifty miles southeast of Santa Ana, you reach the very bottom of Texas, in a lower corner of Brownsville. Just at the outskirts of the city, you turn south on Las Palmas Road that takes you over the levee and through an opening in the border fence, and you arrive at the Sabal Palms Sanctuary. It is known for birding, butterflies, and among herpers, its claim to fame is the presence of such species as Texas indigo snakes, blackstriped snakes, and speckled racers. The Master of Ceremonies, however, is the sabal palm or sabal palmetto, a palm tree that can reach over 60 feet in height and has a crown of fan-shaped leaves. While sabal palms used to grow in groves along a considerable portion of the lower Rio Grande valley, these wild-growing groves or forests of palms have mostly disappeared. The trunks of these palm trees often have a cross-hatched, latticework appearance because when it loses leaves, the bases of the leaves often remain in a sort of upside-down “Y” known as a “bootjack.” On the other hand, if these bootjacks are removed or lost, the trunk has a fairly smooth appearance.
We started our walk through some open woodland and checked out the view from the overlook to the Rio Grande, then headed for the butterfly garden. Along the way, Clint found several noteworthy invertebrates. One was a little black-and-white banded caterpillar with yellow projections or knobs around it. This was the larval form of Forbe’s silkmoth, a very uncommon species. The adult winged form is huge and decorated with bands of reddish brown and yellow, with four translucent teardrop-shaped spots that give it the name “cuatro espejos” (four mirrors) in Mexico. We then entered the Forest Trail, winding through a more closed canopy of sabal palms and other trees. At 11:32am, a fair distance in, the temperature was 77 degrees with a comfortable relative humidity of 49%, with breezes sighing overhead. The forest here is like the Rio Grande Valley’s version of the Big Thicket: dense, biodiverse, and looking like it had been undisturbed since before Texas was settled.
“Bootjacks” on a Sabal Palm
Palms were mixed with acacias, ebony blackbead trees, and the understory a profusion of vines. Without enough sunlight for grass, the Page !11
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The Oasis at the Bottom of Texas (continued) ground was covered in such things as palm fronds, seed pods from the ebony trees, and downed palm trunks here and there, growing moss. It was like sitting on a bench in a prehistoric forest. The trail took us on a short boardwalk over a low place and further along through this semi-tropical wonderland. In a couple of places we saw triangle cactus growing in the dappled light and looking a little out of place in this tropical woodland. It is said to be night-blooming in the summer, with big white blooms that attract hummingbird moths. Down a path into a particularly lush part of this jungle/forest, I sat on a bench for a while looking at the magnificence of the place. Something grew in every available inch of space; vines threaded their way up the latticework of palm trunks, and on the ground under the carpet of living plants must be a complex layer of decaying palm fronds, fallen branches, and fungi, returning previous years’ plants to the soil. How many frogs must be hidden in all this complexity? What lizards prowl through the leaf litter? There are certainly worlds within worlds in this place, from the birds in the canopy to the communities of invertebrates and their predators in the branches, to the various things below that living carpet of plants, the scavenging, root-munching, soil digesting invertebrates and the insects, reptiles, and amphibians that search them out and eat them. We could study these communities of life for years and still have more to learn.
In the Sabal Palm woodland Page !12
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The Oasis at the Bottom of Texas (continued) And then it was time to visit more worlds. We walked along a boardwalk over a part of the resaca (which is a body of water that started out as a bend in a river but then got cut off and isolated, but can be recharged during floods or by rainfall). Further along the trail, at the edge of a small pond, we saw a white peacock butterfly, which was an unusual enough find to catch Clint’s attention. The upper wings are pale, with beige and light brown markings that has been suggested to resemble antique lace. According to the Butterflies and Moths of North America
White Peacock
website,10 it is found in south Texas and down through Central America, and its habitat is “open, moist areas such as edges of ponds and streams” – a perfect description for where we found this one. A visit in June of this year put an interesting postscript on the story of Sabal Palms. As we followed the trail into the old butterfly garden, it was hard to recognize the garden plots and little pond that formed a little pollinator oasis in previous years. The plots were still there, with withered pollinator plants shedding most of their leaves under the similarly dessicated trees that usually provide dappled shade. Bees landed on the duckweedchoked puddle that had been part of a man-made pool provided for the butterflies. The trail led away past the triangle cactus that now looked much less out of place in a dry and brown woodland. The promise of water in the resaca pulled us forward; if there was any water in the little oxbow pond, we could focus on wildlife around that little oasis. The margins were still green, but the water was gone, and so was the wildlife except for a green anole lizard and one swallowtail butterfly. Call it inadequate planning (we could have checked recent rainfall patterns better) or the luck of the draw in a place where rainfall is inconsistent and the climate arid. Outside the immediate area of the river delta is the thorn scrub of south Texas and northeastern Mexico, places that can Page 1 ! 3
Triangle Cactus in better times
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October, 2018
The Oasis at the Bottom of Texas (continued) alternate between desert aridity and pulses of tropical moisture. I guess it is no surprise that this sanctuary goes through droughts and becomes dry and brown. It has to be a resilient place to bounce back when the rains come and the withered landscape transforms back into the tropical wonderland that we saw last October. Boca Chica – the End of the River Further northeast of Brownsville, following the river and the part of the LRGV National Wildlife Refuge that hugs the river’s northern banks, you pass places where there are “islands” of thorn scrub habitat surrounded by the low vegetation typical of tidal flats. Eventually the last vestiges of scrub give way to sandy tidal flats with shallow pools, just before arriving at a line of sand dunes. It is the end of the land, and the end of the Rio Grande’s course. East of this spot, you are in the domain of the Gulf of Mexico. The road comes to an end at Boca Chica Beach, that line of dunes and the tidal zone where the sand is continually lapped by waves, smoothed out and hard-packed. It is leased by Texas to the U.S. Fish & Wildlife Service and seems to be (thankfully) less-visited than places like Padre Island. The two times when I have visited, there were people scattered near the road’s end, but you could wander southward a fairly short distance and have the place mostly to yourself. If you can stand the continuously pestering insects (sand flies?), the dunes are delightful to explore. They are criss-crossed by runners of beach morning glory, which form small clumps or mats, giving a little stability to the dunes and providing shade for the resident keeled earless lizards. This is one species – Holbrookia propinqua – of several “earless” lizards, so called because they lack external ear openings. This one is found south of San Antonio in parts of the South Texas Plains with open, sandy habitat, and of course the coastal sand dunes offer such habitat in abundance. At Boca Chica, they dart from
Keeled Earless Lizard
place to place in a blur of speed, feeding on spiders and insects and taking refuge in the burrows of sand crabs or simply digging shelters beneath a clump of morning glory. These lizards can be tricky to photograph. First, you have to find one without alarming it and causing it to dart twenty feet away to disappear in the dunes. Then, if your experience is like mine, you stand in the Page !14
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Dunes at Boca Chica intense heat of the sun, ignoring the biting flies, and pull the lizard up in the zoom lens. Occasionally you find one that sits still while you focus and decide on what angle you want, near the ground or above. They are pale, with the double row of dorsal blotches nearly washed out, and their backs are flecked with very pale yellow or bluish specks. This year, I tagged along with Clint and his family and saw Boca Chica for a second time. We got there about 8:30am in order to avoid the worst of the day’s heat, and the tide was high on the beach. While I took a few photos of the vegetation in the dunes, and Clint got a couple of photos of the keeled earless lizards, for the most part we walked through the edge of the surf and listened to the thunder of the breakers coming in from the Gulf of Mexico. It was, at least for this morning, Zev’s favorite place on earth, and watching him jump into the breakers or settle into the water and sand as the waves retreated, we remembered how
Beach Morning Glory
wonderful the world can look when you are nine years old. Page !15
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The Oasis at the Bottom of Texas (continued)
Boca Chica beach Among the Great Places of Texas I hope that this sketch of a few of the places within the Lower Rio Grande Valley conveys a little of the beauty and diversity of this area, little treasures tucked away among the urban sprawl and agricultural fields of these four counties. They need our ongoing support, because urban and economic growth always exert pressure on such places. As long as our society insists that growth is always good, and as long as people see nature as an optional enrichment experience and not as a system that sustains our lives, preserves will be under threat. There will be people who want to sell drilling rights within them, or who will fragment or isolate them into little patches that cannot continue to be what they were. There will be people who want to wall them off or simply destroy them by selling them off. Unless we raise our voices to insist that we want a world that truly values wild places, they will eventually be gone. Go see the LRGV. Walk through the palm woodland and along the resacas. Go see where ocelots and tortoises live in the thorn scrub, and listen to the thunder of the waves at Boca Chica.
d Notes: 1. Rio Grande Valley Texas. http://riograndevalleytx.us (accessed 7/20/18) 2. Peters, R., Ripple, W.J., Wolf, C., Moskwik, M., Carreon-Arroyo, G., Ceballos, G., Cordova, A., Dirzo, R., Ehrlich, P.R., Flesch, A.D., List, R., Lovejoy, T.E., Noss, R.F., Pacheco, J., Sarukhan, J.K., Soule, M.E., Wilson, E.O., & J.R.B. Miller. 2018. Nature Divided, Scientists United: U.S.-Mexico Border Wall Threatens Biodiversity and Binational Conservation. Bioscience (in press).
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Volume 9, No. 2
The Oasis at the Bottom of Texas (continued) 3. The Conversation. Today’s US-Mexico “Border Crisis” in 6 Charts. https://theconversation.com/todays-us-mexicoborder-crisis-in-6-charts-98922 (accessed 7/28/18) 4. U.S. Fish and Wildlife Service. Lower Rio Grande Valley: La Sal Del Rey. https://www.fws.gov/refuge/ Lower_Rio_Grande_Valley/visit/la_sal_del_rey.html (accessed 7/29/18) 5. Butterflies and Moths of North America. Mercurial Skipper. https://www.butterfliesandmoths.org/species/Proteidesmercurius (accessed 8/23/18) 6. National Butterfly Center. Checklist of Butterflies Seen at the National Butterfly Center. https:// www.nationalbutterflycenter.org/images/NBC_Butterfly_Checklist.pdf (accessed 8/23/18) 7. Texas Monthly. Federal Border Wall Spending Spares Wildlife Refuge, But Not Much Else. https:// www.texasmonthly.com/news/federal-border-wall-funding-spares-wildlife-refuge-not-much-else/ (accessed 9/1/18) 8. All About Birds. Great Kiskadee. https://www.allaboutbirds.org/guide/Great_Kiskadee/overview (accessed 9/1/18) 9. Tveten, J.L. 1993. The Birds of Texas. Fredericksburg, TX: Shearer Publishing, P. 187. 10. Butterflies and Moths of North America. White Peacock. https://www.butterfliesandmoths.org/species/Anartiajatrophae (accessed 9/1/18)
Crab Spider at La Sal Del Rey Page !17
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Up Against the Wall: Three Species Vie for Survival in the Rio Grande Floodplain Marianna Treviño Wright The Rio Grande Valley is not a valley, at all. It’s a surprisingly flat stumble of rock, sand and clay spilling into the mouth of the Laguna Madre, at the Gulf of Mexico. It’s an international divide, fluid and powerful as the trade winds and migratory pathways of the creatures that have crossed it for millennia. It’s a boisterous, bubbling-over of electric, neotropical birds and azure, velvet
National Butterfly Center
butterflies; a blinding blast of shimmering brass and a colorful, melodious cascade that shamelessly sings ‘Canciones de mi Padre’.
More than the heat and the spice, the dust and the dollars, the Rio Grande Valley is home to some of the most humble and hospitable people in the world. In spite of oppressive poverty and hardscrabble gains, residents welcome all comers with ‘Mi casa es su casa.’ Ironically, the United States gleefully embraces margaritas, mariachis and Cinco de Mayo, but refuses to adopt the mentality of the venerable culture that spawned all this. Now, President Trump has secured funding to cleave the Valley in two, dividing the land from the people and the river that so richly supplies us. This September, contracts are set to be awarded for Phase 1 of renewed border wall construction in Hidalgo County, the entirety of which will be walled off from the Rio Grande, except for 3.3 miles through the Santa Ana National Wildlife Refuge. In a cruelty few comprehend, the border wall will be built up to two miles inland from the river, where a desolate No Man’s Land will appear as a new territory known simply as Border Patrol’s Enforcement Zone. According to written documents distributed by the Office of Border Wall Program Management Office, “the enforcement zone would be an area extending from the south/river side of the levee wall or bollard wall approximately 150 feet. All vegetation within the 150-foot enforcement zone will be cleared.” In addition, LED lighting will be installed to illuminate the enforcement zone at night, and an allweather aggregate patrol road will be built there to facilitate vehicle traffic. The plans call for towering steel bollards atop the 18 foot-tall concrete levee to be spaced six inches apart, for visibility’s sake. This “Wall of Hate,” as some have described it, will be a Wall of Death. According to Page !18
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Up Against the Wall (continued) specifications, the total height of the levee/border wall will be at least 30 feet (a height from which human beings are unlikely to survive a fall). Those who do not perish behind it, may be lost traversing it; but there will be unintended victims, as well, including threatened and protected species like the Texas Indigo, the Texas Tortoise and the Texas Horned Lizard. All terrestrial creatures, this trifecta of fascinating reptiles love the sandy loams of the Rio Grande Valley, where they burrow to escape the blistering sun. If you are unfamiliar with this trio of docile, cold-blooded beauties, here’s a primer: The Texas Tortoise (Gopherus berlandieri) loves the Tamaulipan thornscrub peculiar to deep South Texas, where their preferred cactus, the common prickly pear, fruits and flowers, from spring to fall. Heavily exploited by pet suppliers (although protected by Texas Parks & Wildlife Department) and traffickers in exotic species, the Texas Tortoise is most threatened by human beings and highways. Their
Texas (Berlandier’s) Tortoise
population problem is further
compounded by low reproductive rates (two – three eggs per clutch, one – two times per year) and delayed sexual maturity, where females may not be ready to breed until the age of ten. The Texas Indigo Snake (Drymarchon melanurus erebennus) is a relative of the Eastern Indigo, the longest native snake in the U.S. Known to reach 8- 9 feet, the mature indigo requires considerable range to forage and males seek to establish their own territory. The indigo is especially beneficial to human beings as it feeds on small mammals and other snakes, including rattlesnakes, to whose venom it is immune. Known to cohabitate with Texas Tortoises, the indigo is also most jeopardized by people—especially the ones who think the only good snake is a dead one! Littlest, but not the least of these, is the Texas Horned Lizard (Phrynosoma cornutum). Affectionately referred to a “horny toads” by generations of Texans and tourists alike, one used to be able to buy these miniature, Jurassic Era throwbacks as souvenirs at roadside stands on your way through town. Best known for squirting blood from their eyes as a defensive tactic, these fierce-looking lizards feature prominent spikes on their heads and Page !19
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Up Against the Wall (continued)
Texas Horned Lizard peeking out from under the leaves
spines on their soft bodies which protrude when they puff up to avoid being eaten. This particular antipredation device serves as a deterrent and makes them difficult, if not impossible, to swallow. Horned Lizards maintain healthy ecosystems by consuming copious amounts of harvester ants, as well as some termites, beetles and grasshoppers. They are most threatened by habitat loss and the use of pesticides against insects, their principal food source.
All three of these burrowing creatures need to live in areas that are not prone to flooding, where they would be subject to drowning; and all three may be found throughout the Lower Rio Grande Valley Wildlife Conservation Corridor, which contains the majority of the tiny remnant of native habitat found in this region. The big problem is this: the corridor intended to preserve local populations of these species runs primarily along the banks of the river, and almost all of it will soon be behind the border wall. This means when the Rio Grande River overflows its banks, as it is does periodically, all three threatened species will be trapped between the raging river and the impenetrable 18-foot base of the wall, unable to scale the ninety-degree, vertical, concrete slab to dry land before the floodwaters take them under. During our last catastrophic river-flooding event, namely Hurricane Alex (2010), terrestrial species survived in places where the sloped, earthen levees existed as they were able to scurry, slither and slog their way up the embankment and out of the floodway; however, where the border wall existed, these creatures were not so lucky. In fact, hundreds of carapaces from Texas Tortoises were collected by citizen scientists and members of the local Sierra Club, when the floodwaters receded after four long months. As a child of the Rio Grande Valley, a daughter of la frontera, a conservationist and an accidental community activist, I am appalled by the short-sightedness of the powers that be. I am exasperated by the proposed
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Up Against the Wall (continued) solution to a problem that does not truly exist. And I am outraged by destruction of habitat and wildlife that will occur as the result of the border wall. In case you didn’t know, this is NOT business as usual; this is anything BUT typical. Threatened and endangered species of every kind are on the chopping block for this wasteful public works project, along with every law passed to protect us and our natural treasures, given the government’s authority to waive them by virtue of the REAL ID Act. Under this act, the government is allowed to disregard thirty-seven federal laws that protect such things as clean air and water.1 In the name of national security, obscured by a specter of cartel thugs, “Mexican rapists” and imaginary spillover violence, President Trump is waging war on the borderlands. His policies are devastating our communities and decimating already-fragmented landscapes, despite our best efforts to save the remarkable residents of these incredible places. Up against the ridiculous wall, I am repeatedly reminded of my grandfather’s admonition, “A cada necio agrada su porrada.” In English this means, “Every fool is pleased with his own folly.” Fortunately, Mother Nature is wise beyond words. In the end, our best shot at surviving the environmental disaster that is the border wall may be the mighty Rio Grande River, as it will not be restrained; nor will it suffer the arrogance of man—of certain men—forever. Ultimately, the delta decides what will stand and what will fall, in her coursing channel.
d Notes: 1. Sierra Club. Laws Waived On the Border. https://www.sierraclub.org/borderlands/laws-waived-border
Marianna Treviño Wright is the executive director of the National Butterfly Center, a project of the North American Butterfly Association. She is a "Valley girl" commited to species conservation and environmental education, so the most unique creatures and features of deep South Texas may be protected for future generations. A graduate of Columbia University, she has worked in for-profit and non-profit sectors, where she excels at organizational development.
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Trinity River Turtle Survey Andrew Brinker
This male snapping turtle weighed 7.9kg and had a carapace length of 32.5cm In the fall of 2017 TCU’s Andrews Institute of Mathematics and Science Education funded a proposal to conduct a turtle survey with students from Paschal High School in the Trinity River. The goal of the project is to get students outside and involved with science and research. On Sunday October 15th, with thunderstorms threatening and the temperature plummeting, we began the survey. Turtle trapping is a waiting game and we kept busy by googling turtle jokes and watching the birds along the river. After a few hours we pulled the traps and were delighted to find four turtles, two razor-backed musk turtle (Sternotherus carinatus), a red-eared slider (Trachemys scripta elegans) and a river cooter (Pseudemys concinna). The razor-backed musk turtles were a pleasant surprise, as we expected to find common musk turtles (Sternotherus odoratus). The measurements taken include carapace length, carapace width, plastron length, shell height and weight. The turtles are also marked using shell notches along the marginal scutes following the North American technique (Nagle et. al. 2017. Herpetological Review 48(2)). Lastly, a PIT tag is injected subcutaneously near the back right leg for permanent identification. Page !22
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Trinity River Turtle Survey (continued)
The pair of razor-backed musk turtles trapped on the first day of the survey. The sexes are easily determined by the size of the tail (male on the left) The monthly surveys were slow in the winter months with only five more turtles trapped from November through February. The turtle activity increased exponentially in March, with spring on the horizon. We were able to survey on three different days in March, and trapped 62 turtles! We also captured our fourth species of the survey – snapping turtles (Chelydra serpentina). Just like the bottom dwelling razor-backed musk turtles, male snapping turtles are larger than females. Removing the turtle from the trap left me feeling as if I had just been in a wrestling match. I later learned that it is much easier to extract large turtles with the trap collapsed. Snapping turtles also provide the opportunity to show students how to properly handle these impressive turtles. The most common mistake is to lift the turtle up be the tail, which can result in the separation of vertebrae. Grabbing the back legs of the turtle keeps you out of biting range, while not hurting the turtle. If lifting the turtle up off the ground it is best to put one hand on the plastron. The culmination of the survey for the school year was a field trip on May 23 - World Turtle Day. Fifteen students helped bait, set traps, and process turtles. We captured a record 51 turtles in the traps that morning, which was more than enough work to keep the students busy. As the project was funded by TCU’s Andrews Institute, Jenny Moore, a communication specialist was on hand to document the innovative learning Page 2 ! 3
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Trinity River Turtle Survey (continued) experience. Jenny created a great video that covers many aspects of the survey, as well as following a single razor-backed musk turtle as it is measured, marked, sampled for diatoms, and then released back into the Trinity River. The video can be seen with the QR code to the left. QR codes can be read by most smart phone cameras by focusing on the image. The school year ended the week after World Turtle Day, and the survey kicked into high gear. For nearly the entire summer, the Trinity River “turtle team� was out trapping and processing turtles. By the end of July we had marked over 500 turtles, and recaptured more than 100 of them. The species being caught in the traps were not consistent throughout the year, with the exception of red-eared sliders. We captured the majority of the snapping turtles (Chelydra serpentina) between March and early June. Whereas our first pallid spiny softshell (Apalone spinifera pallida) catch did not occur until April 28th, and as the summer progressed they were in nearly every trap.
Five species of turtles were captured on World Turtle Day, including 16 recaptures
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Trinity River Turtle Survey (continued)
The first pallid spiny softshell trapped on April 28th. There are bite marks from other softshells on the carapace just above the left arm. The most coveted species of the survey are Mississippi Map Turtles (Graptemys kohnii). We have only caught a single male in a trap, but managed to capture four more by hand as they were feeding on mussels. The extreme difference in morphology between the sexes allows them to occupy different niches, and thereby avoiding
A male Mississippi Map Turtle (Graptemys kohnii). An average size adult, this male weighed 172 g and had a carapace length of 11.3 cm. The white eyes are a quick way to identify this species. Page !25
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Trinity River Turtle Survey (continued) competition. The males are tiny and have narrow heads, whereas the females are gigantic with jaws built for crushing mollusks.
An adult female Mississippi Map Turtle (Graptemys kohnii) with her impressive jaws. This female weight 1727g and had a carapace length of 23.5 cm. She was 10 times as heavy as the adult male in the photo above. One of the primary goals of a mark recapture study is to determine the population size for each species. Although there are statistical programs and multiple formulas used by scientist, the general premise is very simple – the percentage of recaptures allows you to estimate population size. (100/recapture rate X total individuals marked = estimated population). For example in the figure below 82 of the 349 red-eared sliders were recaptured which is approximately 25%. This indicates that 349 turtles is 25% of the population. In this case you simply multiply 349 times four, which estimates the population in our study site is close to 1400. All of these population estimates are based on less than a years’ worth of data and the accuracy will increase significantly with time. The recapture rate for common snapping turtles was also 25% which would provide an estimated population size of 64. Razor-backed musk turtles recapture rates were at 12%, giving an estimated population of 483. The math on the pallid spiny softshell works out to an estimated 530 turtles (100/11.5 x 61). There wasn’t enough data to determine population size in river cooters and Mississippi Page 2 ! 6
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Trinity River Turtle Survey (continued) map turtles. We have caught two introduced yellow-bellied sliders (Trachemys scripta scripta), which were undoubtedly released pets.
An adult female river cooter with downtown Fort Worth in the background. This female weighed 3585g and had a carapace length of 29.8cm. Page !27
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Trinity River Turtle Survey (continued) The proximity of the study sites has played an integral role in the success of the project. Many students are able to ride their bicycles to the surveys along the Trinity Trails, with the river only a couple miles from campus and less than a mile from downtown Fort Worth. This has also helped foster a great relationship with colleagues at Texas Christian University that are helping mentor several Paschal students during our monthly surveys. Four students have already coauthored multiple posters, a feat usually reserved for college students. We hope that other educators, and citizen scientists, will be inspired to find their own research niche close to home.
Andrew Brinker teaches Environmental Science and Biology at Paschal High School, the oldest and largest high school in Fort Worth. He earned a Bachelors in Zoology from Michigan State University, and a Masters in Biology under Gary Ferguson at Texas Christian University. Andrew loves to be outside learning natural history, and when he isn't in the Trinity River catching turtles, he enjoys camping with family and friends.
A book that describes hiking, canoeing, and wading through all of Texas’ ecoregions, in search of herps and the experiences that these ecoregions offer. Available for pre-order from Amazon, Barnes & Noble, and Texas A&M University Press. Scheduled for release on 11/05/18.
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Bucket List Places Destinations You Don’t Want To Miss
Sabal Palm Sanctuary - http://sabalpalmsanctuary.org Located at 8435 Sabal Palm Grove Rd, Brownsville, TX 78521, the sanctuary is open from 7am to 5pm on most days (closed Wednesdays, Thanksgiving, Christmas, and New Years Day, and periodically may be closed for maintenance). It is owned by Texas Audubon but leased to the Gorgas Science Foundation which operates the refuge.
Texas Field Notes is a quarterly publication, with stories about wildlife, conservation news, and color photos, all focused on preserves, refuges, and other places in Texas. It can be downloaded from greatrattlesnakehwy.com and from https://issuu.com/texasfieldnotes.
We hope you will share Texas Field Notes with friends, schoolteachers, scout groups, and others who may enjoy it and learn from it. We also hope that those of you who are writers and herpers, birders, etc. will consider contributing something that describes Texas’ natural history in a relatively nontechnical way and includes a photo or two. For questions, ideas, or comments, please email: texasfieldnotes@gmail.com. In fact, please consider emailing us just to let us know how you think we’re doing. We would love to hear from you!
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