Heeding the Call: Conservation of the Houston Toad

If we could step back in time to the end of the 19th century on a warm spring evening in eastern Texas, we’d be transported to a picturesque landscape. The countryside was dominated by grasses and short plants, dotted with clumps of trees. This unique and beautiful ecosystem, which has largely been lost, is called Post Oak Savannah. It’s a transition zone between the longleaf systems of the southeast and the grasslands of central Texas.

A spring night in the past would’ve also likely been punctuated by a chorus of the peaceful trills of the Houston toad. Today, the toad’s calls are becoming harder and harder to hear as its populations dwindle. This small toad species (about two or three inches long) with a perpetual frown and warty skin splattered with orange and brown splotches is holding out in the pockets of habitat that remain. 

It’s found in a narrow area nestled between Houston, Austin, and Dallas and nowhere else in the world. Unfortunately, though, it hasn’t been spotted within the limits of its namesake city, Houston, since the 1960s. 

The charismatic but secretive Houston toad was only first discovered by scientists in the 1940s and was described in 1953. Then, throughout the 1950s, its populations declined sharply. For this reason, it was one of the first amphibians federally listed as an Endangered species. It was listed in October 1970 under the Endangered Species Conservation Act of 1969, a precursor to the Endangered Species Act. 

These Endangered toads are hanging on in the suitable habitat that’s left – swaths of forests with sandy soils and remnant Post Oak Savannah. That habitat, however, has been reduced, fragmented, and degraded by development, fire suppression, overgrazing, years of drought, and invasive species, including fire ants and feral hogs. Fire suppression since the 1850s has resulted in an increase in the brushy understory, which blocks light from reaching the woodland floor and gradually eliminates the grasses and small plants the toads need for cover. If all of that weren’t enough, we also lose them to vehicles during their migration to breeding ponds.

Before their seasonal migration to mate, they stay underground in burrows for most of the year, living solitary lives. They’re termed explosive breeders because they gather in large numbers for short periods to breed. However, sadly, these events no longer involve the sizable number of frogs they did in the past. During the breeding season, males gather first in shallow, temporary water sources, like small pools, puddles, flooded pastures, and stock tanks, and issue a high-pitched, high-speed call that sounds like a small bell vibrating quickly. Females respond to the calls by migrating in groups, which is when they’re most vulnerable to being struck by cars.

To give Houston toads their best chance, ARC is restoring and connecting these habitats, from their breeding sites to the upland areas they use for the rest of the year. These efforts are carried out throughout the toad’s range in the Sugar Sands PARCA, or Priority Amphibian and Reptile Conservation Area. This high-priority PARCA was one of the first to be listed in our Top 25 PARCAs. In Sugar Sands, we’re partnering with landowners to open up the understory, first through mulching of understory overgrowth, then using prescribed fire to limit regrowth and mimic the historic fire regime. 

“If you build it, they will come (sometimes with a little help),” explained ARC National Programs Coordinator José Garrido. “Recovery of Houston toad populations can’t just occur on public lands. It’s an uphill battle that requires the cooperation of private landowners and a diverse network of organizations we’ve partnered with, including zoos, land trusts, and state agencies.”

In fact, our partners have been working hard for decades to bolster Houston toad populations. Millions of eggs, tadpoles, and juvenile frogs have been raised in captivity and released back onto the landscape by the Houston Zoo, Fort Worth Zoo, Dallas Zoo, US Fish and Wildlife Service, Texas Parks and Wildlife Department, and Texas State University. ARC will soon be supporting these population-increasing measures. 

Our partners in the Houston Toad Recovery Program are seeing, though, that critical toad habitat continues to be lost despite these incredible reintroduction efforts. If Houston toads are to persist, we must pair reintroduction efforts with widespread habitat protection and enhancement. 

And their persistence is critical. “Besides being an all-around amazing and beautiful species, the Houston toad deserves a medal for being one the first amphibians to be federally listed,” said Garrido. “There are only two ways out of this exclusive club, extinction or delisting. I’m proud to be working with our partners on the latter – to ensure future generations can hear its trilling call in the wild.”

Although they’re still rare and Endangered today, with your help, we’ll work tirelessly to give these big-eyed beauties their best odds for tomorrow. Because Houston toads are essential to the ecosystems that sustain us, they’re essential for us. When we conserve Houston toads, other amphibians, reptiles, and the rest of the biodiversity in PARCAs across the US, we’re also saving ourselves.