Disappearing Amphibians

“Disappearing Amphibians” talk by UT Jackson School of Geosciences at Sibley

Published Jan 26th 2009 in Wildlife

On January 30th students, teachers, families, and the general public are invited to attend an evening of scientific exploration at the Sibley Nature Center as the University of Texas’ Jackson School of Geosciences and the Environmental Science Institute (University of Texas at Austin) presents via webcast "Silent Spring to Silent Night." Ms. Jennifer Olori, a researcher in the area of amphibian evolution, will host the event and be your live area expert. The evening will begin at 5:45 p.m. with refreshments and discussion of the displays in the Sibley Nature Center (1307 E. Wadley) and a demonstration by Dr. Paul Mangum of Midland College. Pre-lecture interactive exhibits and K-12 teacher workshops are provided free to the public before the lecture. At 6:45 p.m. Olori will give a brief introduction, covering amphibian life history, fossil record, and conservation, followed by University of Texas College of Natural Sciences Professor Dr. Tyrone Hayes talking via webcast about how amphibians are disappearing throughout the world.

Dr. Tyrone B. Hayes’s work paves the way for an integrative approach to understanding how an organism reacts to changes in its environment. Recently his work has gained international recognition for demonstrating how atrazine, a widely used pesticide which is now found in many water sources, has been shown to alter reproductive development in frogs even at extremely low levels. Beyond his integrative work in conservation, he has won numerous teaching awards, conservation awards, and recognition as a leader in the scientific community. Dr. Tyrone B. Hayes's work is transforming biology one battle at a time. From a very early age, he knew that he was interested in biology, amphibians in particular. Always fascinated by frogs and toads, this fascination turned into a reality and a career.

One of the most spectacular events of each year on the southern Llano Estacado is the mass emergence of several species of toads in response to rain. Thousands of toads hop (sometimes more than two miles) to a playa filled with rainwater, where they spend the next two nights singing in concert. Their chorus can be heard for up to two miles away, and is deafening when a person stands at the edge of a filled playa. Within a week, the playa is filled with thousands upon thousands of tadpoles constantly eating to grow fast enough to mature before the playa dries. The toadlets of each species seem to leave the pond at the same time. Sometimes what seems like millions of toadlets make the ground seem to quiver as they hop away to bury themselves before the ground dries. Both the adult toads and the toadlets eat billions of grassland termites (which swarm after a rain, too.) Many of the playas in the cropland of the northern Llano Estacado are quiet, though, for agricultural chemicals and disturbance has ended their chorus.

Tiger salamanders also live in the stock ponds of West Texas ranches. The salamanders also live in some of the playas, despite long periods when the little circular rainwater lakes are dry. Salamanders sometimes mate in February, somehow able to withstand the cooler temperatures of the water. Sibley members and staffers have seen salamanders swimming in swarms under ice in stockponds in past years. In a few select permanent playas of the Llano Estacado, tiger salamanders sometimes never grow out of their water-bound larval form (known as Axolotl), but are still able to reproduce.

Two races of Leopard Frogs also live on the southern Llano Estacado. At the Sibley Nature Center we have found a few mutated specimens. In other parts of the United States, the occurrence of mutations in Leopard Frogs has researchers concerned. The Leopard Frogs at the pond at Sibley have also suffered from what we believe is a fungal disease, for their carcasses are found with their mouths filled with white “hair” which appears to be a fungal growth, but in recent years the problem has not reoccurred. The populations of the frogs in the pond remain at a low level compared to what was present twenty years ago. Blanchard’s Cricket Frogs are found in the rivers that begin at the eastern edge of the Llano Estacado, and sometimes are found in ranch ponds along its eastern escarpment.

Bullfrogs are an introduced species to West Texas that has proven detrimental to Leopard Frog populations. The huge bullfrogs eat small Leopard Frogs. Unfortunately, bullfrog tadpoles are still sold by local outlets for people with ornamental ponds. Despite the fact that at Midland’s I-20 pond the bullfrogs have taken over, two years ago Master Naturalists found thousands of young narrow-mouthed toads leaving the pond. Narrow-mouthed toads are a locally unusual species. These toads have pointed noses like frogs, do not hop or leap, but merely walk, and have slick skins like frogs. They often reside in tarantula burrows when there has been no rain. Their song is more like the buzzing of bees.

The most common toad here is the Plains Spadefoot, which smells like peanuts. The green-spotted Couch’s Spadefoot (which can remain underground for at least two years without emerging) is also a common species in the region. Southern Spadefoots, Texas Toads, Great Plains Toads, and both the eastern and western races of the Green Toad are found locally. In the waterholes of the sanddunes and in the rocky canyons of Western Texas Red-Spotted toads are found. Woodhouse’s Toads are found in the northern Llano Estacado and along the breaks and canyons of the eastern edge of the Llano.

The diversity of amphibians on or near the Llano Estacado is surprising to most folks. Despite long droughts and some cold winters, amphibians play a major role in the region’s ecology.