| The Qilian Mountains are located at the northern foot of the Qinghai Tibet Plateau and are a priority area for biodiversity conservation in China,as well as an important ecological security barrier in the western region.As one of the top ten national parks pilot in China,Qilian Mountain National Park aims to protect regional biodiversity and the integrity and authenticity of natural ecosystems.Orchidaceae populations are relatively fragile and more susceptible to interference from climate change and human activities,indicating a certain degree of biodiversity.The study of the distribution pattern of orchids is helpful for the in situ protection,ex situ protection,and field regression of orchid plants,and is currently a research hotspot in the field of orchids protection.The research on the conservation value of orchids can screen out priority protected species,which has great practical significance for regional conservation of orchids.This study takes Orchids in Qilian Mountain National Park as the research object.Through field sampling,indoor data analysis,and model simulation methods,the distribution characteristics of Orchids in the area,as well as the potential suitable areas and changes of Orchids in the current and future climate,were explored.An evaluation index system for Orchids protection value was constructed,and the priority protection sequence of Orchids in the area was determined by calculating the protection value,The main conclusions are as follows:(1)(1)There are a total of 17 genera and 37 species of Orchids in the Qilian Mountain National Park,mainly distributed in the eastern and central valleys or under poplar and Qinghai spruce forests.Among them,there are only 7 genera of Orchids,accounting for 41%of the total genera,33 species of terrestrial Orchids,and 4 species of saprophytic Orchids.The distribution characteristics of Orchid plants vary on altitude gradients,with most Orchids distributed between 2500 and 3000 meters above sea level.The spatial distribution pattern of Orchids populations is cluster distribution.The species diversity of Orchids community first decreases and then increases with the increase of altitude,and decreases with the increase of longitude.The association between the community and associated species is low or non association.The distribution type of Orchids genera in this region is mainly temperate,with no tropical distribution type.(2)The simulation results of the species distribution model show that the potential habitat of Orchids in the Qilian Mountain National Park under the current climate is relatively consistent with the actual distribution points,and the model accuracy is high.Under the current climate,Orchids are widely distributed in the eastern and central parts of Qilian Mountain National Park,with a total suitable area of 20589 km~2,a low suitable area of 17131 km~2,a medium suitable area of 3318 km~2,and a high suitable area of 140km~2.The main environmental variables that affect the distribution of Orchids are vegetation coverage index,altitude,and seasonal variation of precipitation.When the vegetation coverage index is greater than 0.9,altitude is about 2800m,and seasonal variation of precipitation is within the range of 97-98mm,the probability of Orchids’existence is the highest.In the future climate(2050),the potential habitat of Orchids in Qilian Mountain National Park will generally expand to the west.The high radiation forcing scenario(SSP585)is more conducive to the expansion of Orchids habitat to the west than the low radiation forcing scenario(SSP126).Compared to the current climate,the total,low,and medium habitat areas in the future climate will increase,while the area of high habitat areas will decrease.(3)A comprehensive evaluation system for the conservation value of Orchids in Qilian Mountain National Park was constructed using the Analytic Hierarchy Process(AHP)and expert consultation method.The relative weight of the indicator layer element"IUCN Endangered Level"is 0.0903,which has the greatest impact on the target layer"conservation value".The relative weights of"distribution frequency within the province"and"ornamental value"are both below 0.05,which has a relatively small impact on"protective value".According to the evaluation system,the evaluation results of Orchids in Qilian Mountain National Park show that the protection value of the orchids is greater than 0.6,such as the Herminium biporosum,Dactylorhiza hatagirea,Corallorhiza trifida,Galearis roborowskyi,Habenaria tibetica,Galearis tschiliensis,Dactylorhiza viridis and Spiranthes sinensis However,the protection value of the Orchids of Herminium monorchis,Neottia puberula,and Goodyera repens is lower than0.5,indicating a lower priority for protection.Therefore,the protection value of Herminium biporosum is the highest,and it should be given priority protection in the Qilian Mountain National Park.To sum up,there are various Orchids species in Qilian Mountain National Park,mostly distributed under the forests in the east and middle of the National Park(with a high vegetation coverage index),with an altitude of about 2800m.In the future,the suitable habitat for Orchids will expand to the west,and Orchids with small populations and easily disturbed distribution areas,such as Herminium biporosum,should be given priority protection,It is recommended that orchid plants in this area be mainly protected in situ,supplemented by ex situ protection.The results of this study can provide theoretical support for the protection of orchids in Qilian Mountain National Park. |
