Conserving Orchids in the Wild
The Tropical Garden, Spring 2011
By Hong Liu, Ph.D.
The Expected and Unexpected Difficulties of Conserving a Rare, Attractive Wild Orchid
Call me inexperienced in the field of biodiversity conservation, if you wish, because I did and still do romanticize it. That’s why I chose this career and remain passionate about it. But there is no denying that conservation of plants, even charismatic orchids, is challenging. While some difficulties are shared across regions and species, others are unique and somewhat unexpected. This article is mostly about the latter.
Readers of The Tropical Garden may recall an article that I wrote in the Winter 2009 issue on my first journey to a wild orchid paradise, the Yachang Orchid Nature Preserve in southwestern China. I reported on the unusually large populations of many wild orchids. I also mentioned the excitement of the Chinese botanists about the discovery of a population of an attractive, fragile-looking ground orchid, the Guizhuo geodorum, Geodorum eulophioides. They had found it near the preserve a year before my initial visit. The Guizhou geodorum is extremely rare and had not been seen by botanists in more than 80 years. Unfortunately, not long after the joyful rediscovery came the bad news—the site that hosts the only known population of this rare orchid had been severely disturbed by human activities, including corn farming and the planting of exotic eucalyptus trees for paper pulp and timber. These orchids sustained direct physical damage when their underground bulbs were dug up or broken. Farming can also harm the orchid through herbicide and fertilizer use, which can disrupt the orchid’s life-dependent interactions with soil fungi.
I knew that in order to preserve this rare species, local officials would need to be convinced to stop the farming and erect a fence around the key area. I set out to make this happen. To start, I knew that I needed to gather together everyone from the local community who played a role in the conservation of the Guizhou geodorum, including preserve managers, local government officials and farmers. But our first couple of meetings were unproductive, and I realized that the kind of discussion we needed to have was best held at a dinner table. I brought the parties together at dinner, where I drank shots of locally brewed rice wine to show my sincerity and respect for the local community. After that, a fence was erected and farming was stopped within the fenced area.
Once I had gained the trust of the preserve managers and local officials, and with the orchids receiving a healthy dose of international attention (through a high-profile article in Science Magazine), conserving this rare orchid should have been easy, right? Not so. Because of the disturbance resulting from farming, the orchid’s habitat desperately needs restoration to ensure the species’ long-term existence. As a restoration ecologist and advocate for the species’ conservation, I was given the responsibility to supervise this project.
I did not expect to proceed with this task with so little information. Ideally, I would carry out well- replicated restoration treatments completely, partially and not at all, or different combinations of treatments. These would include removal of exotic shrubs vs. leaving them in place, removal of eucalyptus trees (which now function as canopy trees to some extent) completely vs. partially or not at all. Based on the outcome for the orchid population with each treatment, I would recommend a definitive restoration procedure. However, the fenced area is so small, and the remaining number of orchids of concern is so low, that such elaborate ecological experiments are simply not possible.
Of course, it is not an option to take no action at all. Now that farmers are paid to give up their young eucalyptus trees and cornfields, keeping all the eucalyptus trees on site would send the wrong signal. Luckily, there are a couple of things we can do that will benefit the rare orchids right away. The abandoned field where the Guizhou geodorum grows was colonized by an exotic invasive species native to South Florida soon after farming stopped. The tall, dense, vigorously growing weed is choking the orchids. I can recommend the mechanical removal of the shrub during the orchid’s dormant season to give the orchids some breathing space.
In addition, there were a few large Yunnan thin-leaf pines, Pinus yunnanensis var. tenuifolia, on this site before farming. This variety of the Yunnan pine is endemic to the Hongshui River banks where the orchids grow. I can recommend planting pine seedlings from nearby sites to provide canopy cover and gradually replace the eucalyptus trees. Elimination of the eucalyptus trees all at once is not recommended because they function as canopy to provide some needed shade for the habitat.
Even with these recommendations, there are more questions than answers. For example, what is the right combination of vegetation for the habitat? What is the right range of soil pH for the orchid (and its fungal partners)? What is the end point of the restoration?
The responsibility of doing the restoration right is heavy. Not willing and able to bear the weight alone, I have enlisted colleagues, both Chinese and international, to join in planning the restoration. Scientific research, including experiments using seeds harvested from hand pollinations, is needed to further guide the restoration actions. I am hoping to report more good news in the next update.