RESUMO
Chinese caterpillar fungus (Ophiocordyceps sinensis) is a precious traditional medicine which is mostly distributed on the Qinghai-Tibetan Plateau (QTP). Due to its medicinal values, it has become one of the most valuable biological commodities and widely traded in recent years worldwide. However, its habitat has changed profoundly in recent years under global warming as well as anthropogenic pressures, resulting in a sharp decline in its wild population in recent years. Based on the occurrence samples, this paper estimates the potential distribution of caterpillar fungus using MaxEnt model. The model simulates potential geographical distribution of the species under current climate conditions, and examine future distributions under different climatic change scenarios (i.e., RCP 2.6, RCP 4.5, RCP 6.0 and RCP 8.5 have been modelled in 2050s and 2070s, respectively). For examining the impacts of climate change in future, the integrated effects of climatic impact, trading, and overexploitation had been analyzed in detailed routes. The results show that: 1) The distribution patterns of caterpillar fungus under scenario RCP 2.6 have been predicted without obvious changes. However, range shift has been observed with significant shrinks across all classes of suitable areas in Tianshan, Kunlun Mountains, and the southwestern QTP in 2050s and 2070s under RCP 4.5, RCP 6.0 and RCP 8.5 scenarios, respectively. 2) The exports were decreasing drastically in recent years. Guangzhou and Hongkong are two international super import and consumption centres of caterpillar fungus in the world. 3) Both ecological and economic sustainable utilization of the caterpillar fungus has been threatened by the combined pressures of climate change and overexploitation. A strict but effective regulation and protection system, even a systematic management plan not just on the collectors but the whole explore process are urgently needed and has to be issued in the QTP.
Assuntos
Mudança Climática , Cordyceps , Povo Asiático , China , Hong Kong , HumanosRESUMO
This study aimed at understanding the differences in traits of functional twigs and leaves of a typical alpine shrub species, Rhododendron przewalskii, at Kaka Mountain in the headwater region of Minjiang River. Leaf and twig traits were compared for shrubs at different growth stages (flower bud stage and flowering stage) and altitude (3600 m and 3800 m). The effects of spatial heterogeneity on their correlations and trade-offs were evaluated at leaf and twig levels, respectively. Our results showed that twig length was significantly longer at low altitude than high altitude for the shubs at the same growth stage. The number and mass of flowers at flowering stage were significantly higher at high altitude than those at low altitude. At the same altitude, twig mass, number of leaves, total leaf mass, total leaf area and total petiole mass were all significantly greater at the flower bud stage than those at the flowering stage, while the individual leaf mass and individual petiole mass at flower bud stage were significantly smaller than those at flowering stage. Compared with the flower bud stage, the proportion of leaf mass decreased by 13% at the flowering stage, while biomass proportion of twig significantly increased. At the flower bud stage, twig mass had a higher contribution to total twig mass. In contrast, the contribution of total leaf mass to total twig mass was higher at flowering stage. More biomass of leaf was allocated to individual leaf mass at flower bud stage. More biomass of leaf was allocated to individual petiole mass and individual leaf mass at flowering stage at low altitude and high altitude, respectively. At low altitude, allometric growth patterns presented between twig mass and total leaf area, total leaf mass. Similarly, individual petiole mass and individual leaf area had allometric growth. Our results indicated that the functional traits of twigs and leaves varied across both altitude and plant growth stage.