Saving Rare and Endangered Species

When Mercer Botanic Gardens joined the Center for Plant Conservation (CPC) in 1989, it made a pledge to protect some of the country’s most imperiled plants. In late August, Hurricane Harvey put that pledge to the test.

At the time, Mercer maintained about 30 plant species for the CPC’s National Collection of Endangered Plants. Many of these plants are grown in Mercer’s Conservation Nursery, Endangered Species and Native Plant Garden, and Prairie Dawn Preserve, while their seed is preserved at Mercer Botanical Center. When Harvey hit, more than 10 feet of water overwhelmed the Conservation Nursery, one of Mercer’s hardest hit locations. Even after the storm, much of Mercer’s CPC collection was underwater for five days before staff could begin cleanup.

Despite the damage, staff recovered most plant stock and all identification tags. With cleaning and pruning, endangered species such as the Neches River rose-mallow (Hibiscus dasycalyx), trailing phlox (Phlox nivalis), scarlet catchfly (Silene subciliata), and false dragonhead (Physostegia correllii) showed new growth and some even bloomed. Only two out of nine Brazos River yucca (Yucca necopina) seedlings in the Conservation Nursery were lost.

“Mercer’s conservation staff, fortunately or unfortunately, have much experience with pre-hurricane, flood, and wind disaster maintenance strategies for CPC collections,” said Precinct 4 Botanist and Conservation Manager Anita Tiller. “Thus, the conservation collection suffered minimal loss due to our maintenance protocols and diligent post-flood cleanup of nursery stock. Plus, most of our plants are flood resilient!”

Some of Mercer’s most devastating losses were to its garden display collections, said Tiller.

“Mercer maintains and displays an impressive collection of palms and cycads native to subtropical and tropical regions of the Americas and the Old World,” she said. “Mercer lost some palm and cycad specimens as result of the Hurricane Harvey flood. Other specimens have lost their leaves. For those, our horticulturists must wait until spring and check for regrowth to determine whether specimens survived flooding. We are hopeful, as many palm and cycad species are adapted to floodplain habitats.” Although the Mercer Botanical Center building only received eight inches of water, it contains fragile specimens that must be kept in a cool, dry environment, including a herbarium and frozen seed bank for the National Collection of Endangered Plants. Fortunately, the building’s standby generator kicked before the building lost power, leaving Mercer’s seed bank undamaged.

By design, Mercer Botanical Center’s most valuable equipment and specimens are located on the second floor. Mercer’s MERCA and SBSC herbarium collections, which are necessary for documenting Mercer’s rare plant collection, also survived the flood. Losses include a few books in the botanic library that served as reference material for the seed bank and herbarium.

Tiller attributes the botanical center’s recovery to the quick work of Precinct 4 employees and volunteers. “Within two days of the water receding, staff repaired the damaged A/C unit, removed the drywall, and relocated office equipment upstairs,” said Tiller. “Mercer volunteers also assisted staff soon after the flood with cleanup, boxing and moving the library collection upstairs, and Conservation Nursery cleanup and inventory.” Other areas were mostly spared from the worst of the flooding. The Precinct 4 Prairie Dawn Preserve suffered minor erosion along the fence line and continues to serve as a valuable resource for seed collection.

In October and November, Mercer staff surveyed plants and collected seedlings at the preserve from plants including Bracted Gayfeather (Liatris bracteata), Houston Daisy (Rayjacksonia aurea), and Texas Windmill Grass (Chloris texensis). The seeds were then banked at Mercer and at Mercer’s partner location, the USDA National Laboratory for Genetic Resources Preservation (NLGRP) in Fort Collins, Colo, for the National Collection of Endangered Plants. “Volunteers continue to assist us at the Prairie Dawn Preserve, Mercer’s Botanical Center, and the Conservation Nursery with flood recovery and routine maintenance for the collections,” said Tiller.