Title: Effects of the hemiparasitic plant Pedicularis kansuensis on plant community structure in a degraded grassland

Authors: Bao Gensheng, Suetsugu Kenji, Wang Hongsheng, Yao Xiang, Liu Li, Ou Jing, Li Chunjie*.

Journal: Ecological Research

Impact Factor: 1.296

Abstract: Species-rich grasslands have high conservation value because they support diverse floral and faunal assemblages. Alpine grassland is an important and characteristic ecosystem of the Qinghai-Tibet Plateau, but ca. 30 % has been severely degraded by the combined effects of climate change, human activity, overgrazing and rodent damage. One potential method to restore grassland diversity involves using hemiparasitic plants to modify the competitive relationships among neighboring species. A possible candidate is Pedicularis kansuensis, a hemiparasitic plant found in grasslands throughout the Qinghai-Tibet Plateau, but more information on its host associations and its effects on surrounding vegetation is required to assess its suitability. Thus, we examined host associations of P. kansuensis by direct root excavation at a selected site on the Qinghai-Tibet Plateau and found that haustoria formation is non-randomly distributed among host species, with preferential bias for members of Poaceae, Rosaceae and Fabaceae. We also found that aboveground biomass of grasses and legumes was higher in quadrats from which the parasite had been removed than in intact controls, while the biomass of sedges and forbs was unaffected by parasite removal. However, removal significantly decreased plant species richness and Shannon?Wiener diversity. These results suggest that P. kansuensis modifies the competitive balance in grassland communities of the Qinghai-Tibet Plateau, allowing for colonization by subordinate species and thereby enhancing species diversity and contributing to restoration of these degraded grasslands.