Regeneration of Fargesia qinlingensis and Bashania fargesii
in the Qinling Mountains, China
Giant pandas are a unique mammalian herbivore that obtains 99% of its diet from a grass, and a woody grass at that, called bamboo. While pandas have developed external characteristics for eating bamboo, such as large jaw muscles and the famous ‘opposable thumb,' they have few internal mechanisms for digesting this low nutrient resource. For this reason, pandas require large quantities of bamboo every day, 10-40 kg. One scientist estimates the number of bamboo stems eaten each year by a single giant panda to be around 600, or 213,600 per year. This loss of stems could be a concern for two reasons: (1) panda habitat, and thus bamboo, continues to declines despite efforts to preserve large areas, and (2) bamboo rarely flowers, perhaps once every 30-60 years, and subsequently dies. We were interested in the effects of panda herbivory on the regeneration of bamboo stems.
The bamboo family is a fascinating group of plants. They represent one of the evolutionary origins of the entire grass family. They are clonal, meaning they can produce new shoots (called ramets) without flowering, which is called vegetative reproduction, from underground stems called rhizomes. Rhizomes may be bunched (pachymorph), or running (leptomorph), depending on the species. New shoots can grow some 18 inches a day, and shoots in general last from 5-10 years due to their woody structure, unique in the grass family. The non-flowering stage lasts generally 30-60 years (much more in some species), during which time an entire network of rhizomes connecting hundreds and perhaps thousands of bamboo stems is formed, all one individual. Why bamboo species wait so long to flower, unique to the grass kingdom, is unknown, although several theories exist. Individuals flower around the same time as well (called gregarious flowering), and once they flower, individuals die. Thus, large areas may be lost following gregarious flowering events, aptly referred to as die-off events. In the eastern Min Mountians in China , death of 138 pandas was blamed on a gregarious flowering event in 1974-1976 that left entire hillsides devoid of bamboo for panda to eat.
Perhaps this introduces our interest in studying bamboo regeneration. We have developed several projects in and near the Foping National Nature Reserve (FNNR), southwest of Xi'an , Shaanxi Province , China , which build on the work of other scientists. The FNNR is home to the highest density of pandas in China , boasting an average of one panda every 5 km 2 . Pandas typically migrate, spending summers in the high elevation range (> 2200 m) and winters in the lower elevation range of 1700 to 2100 m. Each range has essentially only one bamboo species, Fargesia qinlingensis in the summer range and Bashania fargesii in the winter range, not much of a choice between breakfast, lunch and dinner, and snack times.
Research includes: regeneration following recent and 30-yeald old die-offs, regeneration following giant panda herbivory, historical evidence of bamboo in soils (phytoliths), regeneration of bamboo in canopy gaps, and clonal integration. Click here for PICTURES.
Lu, Zhijun, Wei Wang, Wenhui Zhang, Hong Li, Qing Cao, Gaodi Dang, Dong He & Scott Franklin. 2009. Spatial-temporal patterns of Bashania fargesii bamboo shoot emergence and giant panda herbivory. Biodiversity Science 17:1-9. (PDF - In Chinese)
Wang, Wei, Scott B. Franklin, Yi Ren & John R. Ouellette. 2006. Growth of bamboo Fargesia qinlingensis and regeneration of trees in a mixed hardwood-conifer forest in the Qinling Mountains, China . Forest Ecology & Management 234:107-115. PDF
This research is supported by:
Restoration of Canebrakes (Arundinaria gigantea)
A greater than 98% decline in Arundinaria gigantea (Walt.) Muhl. canebrakes has resulted in a critically endangered ecosystem (Noss et al., 1995). Historical accounts suggest loss of canebrake habitat has resulted in the extirpation (and perhaps extinction) of many species (Brantley and Platt 2001). In addition, canebrakes may have provided important functions in floodplains, such as bank stabilization and buffering upland nutrient and sediment flow ( Schoonover and Williard 2003 ). Thus, canebrake restoration is necessary for maintaining and enhancing biodiversity in the southeastern United States and the restoration of landscape functions. However, transplantation attempts to reintroduce cane have met with limited success (Platt and Brantley 1993; Feeback and Luken 1992), perhaps due to our lack of knowledge on the environmental and physiological requirements of cane transplants. We currently lack an appropriate restoration target for canebrakes, characterizing the historical extent and distribution, and the ecological and physiological constraints. In addition, restoration is limited by the physical difficulty of moving transplants and the use of small, fragmented populations. Because canebrakes provide a habitat for a diversity of fauna, including endangered butterflies (Platt et al. 2001) and avifauna, such as Swainson's warbler (Graves 2001), and because so little is known about the ecology of cane, research is needed to determine factors constraining growth of this unique ecosystem (Thomas et al. 1996). We propose restoration techniques could serve multiple purposes, increasing biodiversity in floodplains as well as buffering of upland anthropogenic activities or streambank stabilization.
Franklin, Scott. B. 2009. Them’s the brakes. Castanea 74:2005-2006 (Introduction to Special Issue on Canebrakes)
Baldwin, Brian S., Margaret Cirtain, D. Scott Horton, John Ouellette, Scott Franklin and John E. Preece. 2009. Propagation methods for rivercane [Arundinaria gigantea L. (Walter) Muhl.]. Castanea 74: 300-316.
Cirtain, Margaret C., Scott B. Franklin & S. Reza Pezeshki. 2004. Effects of nitrogen and moisture regimes on Arundinaria gigantea (Walt.) Walt. Ex Muhl. seedling growth. Natural Areas Journal 24:251-257. PDF
Cirtain, Margaret C., Jenna R. Franklin, and Scott B. Franklin. 2003. Effects of nutrients and shading on Arundinaria gigantea (Walt.) Walt. Ex Muhl. seedling growth. PP. 49 - 56 In: Proc. Tenth Annual Symposium on the Natural History of the Lower Tennessee and Cumberland River Valleys . The Center For Field Biology, Austin Peay State University , Clarksville , TN.