Lewisville Aquatic Ecosystem Research Facility helps save habitats

Published June 19, 2013
Common elderberry planted and flowering as part of the Dallas Floodway mitigation project assisted by LAERF scientists.

Common elderberry planted and flowering as part of the Dallas Floodway mitigation project assisted by LAERF scientists.

In December 2012, during a mitigation planting in Dallas, Texas, UTN graduate student Aaron Schad installs an enclosure to protect a red mulberry from herbivores, while UTN student intern Marinda Griffin observes.

In December 2012, during a mitigation planting in Dallas, Texas, UTN graduate student Aaron Schad installs an enclosure to protect a red mulberry from herbivores, while UTN student intern Marinda Griffin observes.

Accustomed to meeting environmental challenges wrought by Texas floods and droughts, ERDC’s Lewisville Aquatic Ecosystem Research Facility (LAERF) answered the call by the Corps’ Fort Worth District to offset plantings removed during wetland construction as part of the massive Dallas Floodway Project.

This preventative project is under the supervision of LAERF’s Research Ecologist Gary O. Dick with assistance from Research Biologist Chetta Owens and University of North Texas (UNT) graduate student Aaron Schad.

“Much of these mitigation lands lack plant diversity. The new plantings will introduce a rich mixture of acorn-, nut- and fruit-bearing trees,” Schad said.

According to Schad, shrubs and vines will diversify an area now dominated by willows, elms, green ash and cottonwoods, “providing wildlife cover, creating new nesting areas and establishing a greater and more dependable food supply.”

The multi-year planting program will use adaptive management where “each sequential planting will provide important guidance for more effective techniques in future plantings,” Schad said.

The big project picture

In the feature article, “Mitigation plantings in harsh North Texas climate challenge US Army Corps of Engineers team,” (http://www.dvidshub.net/news/105832/mitigation-plantings-harsh-north-texas-climate-challenge-us-army-corps-engineers-team#ixzz2WEyM2jMb), Fort Worth Public Affairs Specialist James Frisinger explained the big picture.

“The Fort Worth District, in support of the city of Dallas, is building two chains of interconnected wetlands on 271 acres near the Dallas urban core that are central to the project’s flood-risk reduction goal,” Frisinger said.

“This 3.7-mile-long wetland complex, more than half completed, improves life safety by creating another pathway, parallel to the main river channel, to better convey floodwaters through the Dallas Floodway System,” Frisinger explained, citing results indicated lowered flood elevations upstream and reduced risk to a multitude of people who live and work in Dallas.

Seeking ideal plantings for challenging conditions

Twelve-inch-deep pots were selected for trees and special water-absorbent soil mixture was added during planting for better survival chances in Texas heat and drought.   

“Species selected also need to be able to survive potential Trinity River overbanking events, which can persist for up to several weeks,” Dick said.

“In our first year plantings, half the plants will go un-watered, the other half will be monitored for soil moisture and watered whenever soil moisture falls to 10 percent or below, while cages will protect some plants from herbivores such as deer and wild hogs.  Once established, it is believed that plants will be able to tolerate both dry and inundated conditions,” Dick said, “but our periodic evaluations will reveal which species need irrigation and/or protection to become established.”

Wintertime survivors, spring rain benefactors

Plantings made during the cool season of 2012-2013 have thus far proven successful, with nearly all plants breaking winter dormancy.  Plant species that have demonstrated to be particularly successful in first year test plantings include pecan, black walnut, common persimmon, red mulberry, eve's necklace, coral berry, river plum, common elderberry , flameleaf sumac, American beautyberry, peppervine, mustang grape, coral honeysuckle, and roughleaf dogwood.

“Biotic disturbance has been minimal and spring rains have eliminated any need for irrigation.  As the heat and dryness of summer approach, the test plantings appear to be well enough established to withstand the harsh Texas conditions,” Dick said.  “In the event that some plants or plant species do not survive summer, adjustments will be made regarding species selection for larger scale plantings that will be made this fall and winter.” 

LEARF will make evaluations on current plantings and those made in 2013-14 to formulate plans for final year plantings in 2014-2015.