| Orchids are highly specialized in various organs,morphological habits varied,pollination is also particularly unique,is the most advanced angiosperms,one of the most advanced group.The growth and reproduction of orchids require specific environmental conditions,and they have a strong dependence on the ecosystem,which can reflect the local biodiversity and conservation status to a certain extent.In this paper,the orchids plants as the research object at the BeiPanJiang upstream valley area along “Qinglong – Guanling” section?ZangKe town of LiuZhi county and BeiPanJiang town of ZhenFeng county gorge area of orchid plant as the research object,Using the methods and principles of biodiversity research of Individual Ecology and Population Ecology.The species composition,distribution,flora,community diversity,habitat type and cause of death,priority protection and other aspects of the study area were studied in a systematic and comprehensive way,so as to provide some theoretical basis for the protection of Orchidaceae in this area.The main results are as follows:(1)there are 34 genus and 72 species of orchids in the study area(including 2 varieties and 1 suspicious species,hereinafter the same).Among them,there are 24 species 12 genera recorded in "Guizhou flora","flora of China"(Among them,16 species and 10 genera are recorded and distributed,but this investigation has not seen,but this investigation did not see.The records are distributed and the actual investigation are 8 species 6 genera),that means the actual investigation and identification of the species is 30 genus 56 species,it increased 48(50%)species and 22 genus(54.55%)compared with the original record.Including five new records in Guizhou,one suspicious species of Habenaria,and Geodorum eulophioides,which has not been reported for many years.Species composition in oligotypic genera accounted for a large proportion,as many as 20 genera,accounting for more than half of the total genera in the study area,which shows the complexity of the species composition and habitat specificity of orchid species in this area.The main types of life are epiphytic orchids,as many as 37 species,followed by the terrestrial orchid,a total of 34 species;and only one saprophytic orchid species orchids,which is the lowest diversity,the least amount of resource category in the study area.(2)In the horizontal distribution,the wild orchids in the area were mainly distributed in the karst mountainous areas such as the town of Xinpu Town in Guanling County,the town of ZangKe Town in LiuZhi Special District and the town of GuangZhao ? HuaGong and ZhongYing in QingLong County and other vegetation are well preserved in Karst mountain and the typical Karst Valley area of MaBu and MaSha River.Including in the form of cluster distribution exist in the karst mountain of well preserved vegetation,less human activities or muggy canyon areas,in the form of random distribution scattered in the secondary broad-leaved forest,coniferous and broad-leaved mixed forest,grass slope,etc.Or in a small area presented in the form of uniform distribution in the grass slope community dominanted by the Gramineous herbs.In the vertical distribution,mainly concentrated in the elevation of 600-1000 m in karst mountain and kanyon lots.Among them,the distribution of terrestrial orchids was broad,and the distribution of each elevation was distributed.The epiphytic orchids were mainly distributed in 600-900 m and 1200-1500 m,and there were few species of saprophytic orchids,which were only distributed in the broad-leaved forest of 900 m.With the increase of altitude,the species number of orchids plants increased firstly and then decreased.(3)According to the method and division principle of Wu Zhengyi's "Distribution type of Chinese seed plant genus"(1991),the 34 genus and 71 species(one suspicious species of Habenaria did not make statistics)of orchids floras in the area were divided into 10 distribution types,2 variants and 9 distribution types,3 variants,and endemic species significantly.From the origin of the flora and geographical features,the genus and species of flora are dominated by the tropical nature distribution,followed by the temperate distribution,indicating that the wild orchids plants have obvious tropical nature in the study area.(4)In species diversity,the peak of species diversity of orchids in this area was in the middle and low elevation.And with the altitude increasing,the Shannon diversity index of the community was positively correlated with Margalef species richness and Pielou evenness index,and negatively correlated with Simpson dominance index.The results showed that when the population distribution was concentrated in the community,the community had higher dominance and lower species diversity.But when the population was evenly distributed among the communities,the community had abundant species diversity and the dominant degree lower.(5)The Karst landform is typical development,with its unique geographical location,rich wild orchid resources have been bred in the study area,the coefficient of karst genus is larger(0.4722),which indicates that the germination degree of the species is large and the habitat is complex and diverse.From the vertical distribution,the genus and species of wild orchids in the study area all changed with the elevation,and the highest peak was in the middle and low altitude.In terms of topography and geomorphology,the distribution of karst limestone in the Karst limestone is dominant,which is mainly related to the high karst area and karst environment heterogeneity in this area.From the slope and its position,mainly in the mountain steep slope in the upper and middle parts where was well preserved vegetation,dangerous terrain,the lower reachability of human and animal.From the aspect of slope the orchid species richness was highest in shady slope.From the community type,some of the broad-leaved forest,secondary shrub forest were preserved well,the plant species are abundant and the human and animal disturbance is lower,so the species diversity of wild orchid is higher.From the niche type,the distribution of the habitat rocks is the largest,which is related to the absolute advantage of the karst topography and epiphytic orchids in this area.(6)The similarity coefficient of orchids plants under different habitat conditions,the degree of similarity are related to the topography in the area and the life style of orchids.Different life type orchids plants have different needs for the ecological environment.The similarity degree of Orchidas plants under different elevation,topography,slope position,slope direction,slope,community types and niche conditions in the study area was not high,the similarity coefficient was less than 0.5,which indicated that the habitat heterogeneity difference which has an important effect on the diversity of orchids flora.(7)In the case of endangered reasons,there are internal and external factors.Internal factors including the population of orchids is too small,low fecundity under natural conditions and a strict environmental requirements.External factors including the habitat loss or degradation of orchids,Biological invasion caused by Ageratina adenophora,Non-standard market trade led to wild orchids plants resources were transition mining,Excessive grazing led to the life history of orchids plants were interrupted or plants and populations disappeared,Human activities such as deforestation,set the mountain on fire caused by a serious threats to orchids and their habitats,and the ecological damage and influence to the orchids plants caused by the travel and photography enthusiasts in shooting orchids or camping.(8)In terms of endangeredness,the greater the priority protection value,the more priority is required.Among them,there are 11 kinds of wild orchids in need of first class protection(V? >0.7),which is Dendrobium scoriarum,Vanda concolor,Paphiopedilum concolor,Liparis esquirolii,Flickingeria tricarinata and Bletilla striata etc.,accounting for 20% of the total number of wild orchids investigated in the study area.There are 30 kinds of wild orchids in need of second class protection(0.60< V ??0.7),which is Goodyera viridiflora,Pachystoma pubescens,Eulophia zollingeri,Dendrobium officinale,Geodorum eulophioides,Coelogyne flaccida,Nervilia plicata,Cymbidium goeringii,Pholidota yunnanensis and so on,accounting for 54.55% of the total number of wild orchids investigated in the study area.There are 12 kinds of wild orchids in need of second class protection(0.50<V ? ?0.6),which is Cymbidium aloifolium,Cheirostylis yunnanensis,Paphiopedilum bellatulum,Malaxis acuminate,Habenaria dentate,Liparis nervosa etc.,accounting for 21.82% of the total number of wild orchids investigated in the study area.There are 2 kinds of wild orchids in need of second class protection(V ?<0.50),which is Bulbophyllum andersonii and Liparis viridiflora,accounting for 3.64% of the total number of wild orchids investigated in the study area.What is worth mentioning is that although the distribution of Geodorum eulophioides in Guizhou has been found again in the study area,the amount of resources is very small,coupled with its immeasurable value in the flower gardening industry,Therefore,its protection should be given special consideration. |
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