Balcones Canyonland Preserve protects endangered species

Balcones Canyonland Preserve protects endangered species

Written by Rachel Youens Thursday, 24 April 2008

As he hikes through juniper and oak trees in the warm spring sun, Bill Reiner is looking and listening. He’s hoping to see a flit of yellow through the trees or hear a bird’s song. Reiner’s office is a 100-acre plot in the Balcones Canyonland Preserve, and he is charged with recording the number of endangered golden-cheeked warblers and other threatened birds in the preserve.

For the past twelve years, the City of Austin and Travis County have worked together to protect one of the regions most environmentally sensitive areas, cobbling together property to form the Balcones Canyonland Preserve. Every spring, biologists from the citys Wildlands Division like Reiner enter the field to ensure the preserve is accomplishing its mission to protect the species native to the Northwest Austin preserve.

“Data from the study plots indicate the birds are doing well there; unfortunately, the statistics don’t show us much of the property outside the preserve,” Reiner said. “The developments around the preserve are building up, and so it’s hard to tell if the increase in population of our study plots is accurate, or if birds are fleeing developing areas.”

History

In 1996, the U.S. Fish and Wildlife Service issued a permit for the City of Austin and Travis County to jointly take control of Northwest Austin land populated by eight endangered species and 27 that were of concern. A Balcones Canyonland preservation plan was created that charged the city and county with creating a preserve system that would cover 30,428 acres by 2016.

Both Travis County and the City of Austin held bond elections to earn money with which to buy up the Balcones Canyonland properties. While Austin’s passed, most recently contributing to the purchase that resulted in this year’s Hazeline Smith trail along Bull Creek, Travis County’s did not.

“The greatest threat to the preserve is ensuring that the preserve is purchased,” Scott Rowin, program manager for the Balcones Canyonland Preserve, said. “It’s currently not completed. We have about 28,000 of the more than 30,000 acres so the greatest threat now is just making sure we can complete it. If it’s not completed, then the configuration and work that went into it may not succeed.”

Protecting the land

The land along Capital of Texas highway spreading out into the Hill Country has always been valuable, prized for its views and proximity to the lake. But the same qualities that make it valuable are also what make it vulnerable.

Beyond endangered species, the area is a recharge zone for the city’s drinking water aquifer. Beneath the surface of the land lie porous karst stone formations that filter the water. The proximity of homes and businesses in Northwest Austin to the preserve can sometimes lead to clashes between nature and civilization that threaten the preserve.

Domestic animals, Reiner said, are one of the greatest threats to the endangered birds on the preserve.

“When cats and dogs roam free, it increases the density of predators in the area,” Reiner said. “Even if a cat isn’t actively catching anything, those small animals that could be caught by cats have to spend more time on alert which is time taken away from food gathering, sleeping, mating.”

Animals leaving the preserve in search of food is another issue that gives birth to several problems. Reiner says people frequently leave pet food on the porch, drawing mice and with them, snakes. The influx of more snakes in the area creates more predators for the birds. He also warns that animals people don’t assume would be a problem can cause havoc.

“People assume squirrels are vegetarians; they eat nuts and seed. But they’ll come to your feeder and eat seed, and then they’ll go eat eggs and young birds.” Reiner said. “Blue jays are another aggressor that we’ve been seeing a lot more recently; they push out the endangered birds.”

Non-native plants spreading from homes into the preserve is another problem. Reiner warns of the deceptively named “Tree of Heaven.” The tree is designed to thrive in a city where conditions are difficult, but in wild land it can take over, actually putting a chemical into the soil that keeps other plants from growing. One place he said you can witness the Tree of Heaven’s abilities is at the Barton Springs greenbelt.

One way Travis County is offsetting the ongoing desire to build in the sensitive area around the preserve is through mitigation fees.

The county has mapped the areas identified as endangered species habitat and before any commercial or residential building may occur in these areas a per-acre fee must be paid. These fees range from $400 per acre in Karst habitats to $4,000 per acre in some particularly sensitive warbler habitats. The funds raised go toward purchasing the remaining land of the preserve.

In the field

“The preserve’s endangered Karst invertebrates are more difficult to monitor because they’re so elusive, a very cryptic species.” Rowin said. “They’re very difficult to find, and the numbers that you find are usually just in the single digits. You usually don’t find many in any one particular survey, so it’s actually hard to track their population.”

According to Rowin the warbler numbers have remained primarily stable and the slight increase is not statistically significant. He said the same is being observed among the black-capped vireos, but that in recent years special vireo habitats have been set up and the birds are expected to begin populating those areas in larger numbers.

The Health of Local Watersheds
-The site of early clashes between settlers and Native Americans. -Almost completely urbanized, but despite this, water quality is considered fairly good.		-The home to several endangered species including the Golden-cheeked Warbler and the Black-capped Vireo. -Portions are listed on the State Water Quality Inventory as being of concern for high nitrate levels.		-Ninety eight percent of Rattan Creek passes through the Edward’s Aquifer Recharge Zone where water travels through caves and sinkholes to “recharge” the aquifer.		-This creek has five seeps and springs and thirteen caves and is home to several endangered species. -Portions of Walnut Creek are listed on the State Water Quality Inventory as being of concern for bacteria and nutrient enrichment.
Length:	9 miles	Length:	11 miles	Length:	8 miles	Length:	22.34 miles
Drainage Area:	11 sq. mi.	Drainage Area:	24 sq. mi.	Drainage Area:	7 sq. mi.	Drainage Area:	43.53 sq. mi.
Overall Score:	Good	Overall Score:	Good	Overall Score:	Good	Overall Score:	Good
Water Chemistry:	Fair	Water Chemistry:	Fair	Water Chemistry:	Fair	Water Chemistry:	Fair
Sediment Quality:	Good	Sediment Quality:	Good	Sediment Quality:	Excellent	Sediment Quality:	Good
Recreation:	Good	Recreation:	Excellent	Recreation:	Very Good	Recreation:	Very Good
Aesthetics:	Good	Aesthetics:	Excellent	Aesthetics:	Good	Aesthetics:	Very Good
Habitat:	Fair	Habitat:	Fair	Habitat:	Marginal	Habitat:	Good
Aquatic Life:	Fair	Aquatic Life:	Very Good	Aquatic Life:	Good	Aquatic Life:	Good

Non-native plants in the preserve

Tree of Heaven - This plant is native to China and was introduced to the United States as an ornamental on the East Coast in the late 1700s, and later into California by immigrants during the gold rush.

Why it’s bad - The plant produces many seeds and when it grows it creates a dense shade that keeps smaller plants from growing. It also releases chemicals into the soil around it that stop other plant growth.

Chinaberry - Chinaberry is a member of the mahogany family and is native to India, southern China and Australia. It was introduced into the United States around 1830 and was planted throughout southern states.

Why it’s bad - Its bark, leaves and seeds can be extremely toxic to humans as well as farm and domestic animals if consumed. Birds, however, can eat the seeds, spreading them in their droppings.

Chinese Tallow - Native to China, these trees were intentionally introduced into the eastern United States in the late 1700s as an ornamental tree and later to the Gulf Coast in the 1900s by the department of agriculture as a resource for the soap-making industry.

Why it’s bad - It has a resistance to native insects here, eliminating the potential for natural control. Its berries and plant sap are toxic to humans and animals. Birds can eat the seeds and subsequently assist in spreading them in their droppings.

0 Comments