Orchid Conservation Research Articles

Orchids conservation action and education community based in Yogyakarta, Indonesia

The development of conservation strategies for orchid species is interesting. Orchid species play an important role in people’s lives, environment, and aesthetics. Orchid species in historical records are threatened with extinction due to the lack of documentation in various regions, increasing theft of orchids for sale, and becoming a massive commercial object. This study discusses the efforts and approaches for conservation and education to protect endangered orchids. This study was conducted in Yogyakarta to understand conservation and education in the community. The method used in this study employs a qualitative approach by conducting literature studies, observations, and interviews with key persons to obtain data and information related to the themes discussed. The results of this study show that action plans for orchid conservation experience both up and down. The education carried out by the community so far involves information dissemination through social media, training, and research in collaboration with universities. The role of education and increasing public awareness of the function of conservation and rare plants has had a positive impact on conservation and eco-education studies in society.

Biodiversity and indigenous knowledge on orchid conservation: Study at a community in Yogyakarta

This study discusses how to manage biodiversity and the role of indigenous knowledge of orchid conservation in Indonesia. Orchids are one of the most attractive tropical flower plants that need attention for conservation. This research was conducted to understand the role and contribution of indigenous knowledge in conserving orchids and protecting natural biodiversity in tropical countries. The questions in this study emphasize how the concept of indigenous knowledge protects tropical biodiversity through a community approach carried out in Yogyakarta. The method used in this research uses qualitative approaches. Primary were data taken from observation, and interview approaches to conservation communities and orchid farmers in Sleman area. Meanwhile, secondary data taken from literature review and bibliometric survey. The purpose of this research is to describe and analyze the role of the community in conserving orchids for the preservation of biodiversity. The results of this study are a model and community or the community way of doing biodiversity conservation in Indonesia start from traditional knowledge that has been passed down from generation to generation and experience about plants. So that life experiences about plants that are passed down from generation to generation are very important and influential in providing education for the community and sustainable science.

Phylogenetic Relationship of Cymbidium Mosaic Virus from the Native Orchids of South Kalimantan, Indonesia

Information on viral genetics, including their phylogenetic relationship, is valuable in controlling viral infection and screening for the development of virus-resistant cultivars in the future. The objectives of this study were to detect and characterize the Cymbidium mosaic virus (CymMV) from the native orchids of South Kalimantan, Indonesia, by the RT-PCR method. Also, to determine their phylogenetic relationship based on a partial genome of RdRp by the ML and PCA methods. Following RT-PCR analysis, one of 10 samples of native orchids used was positively infected by CymMV. In early detection, the RdRp region of CymMV has approximately 530 bp in size. After being sequenced and aligned with other isolates, this region has 121 polymorphic or mutation sites, a GC content of 45.21%, a transition/transversion bias value of 3.52, and nucleotide diversity (0.0415). The phylogenetic analysis revealed that CymMV from South Kalimantan, Indonesia, has closest related to similar isolates from Korea Type 2 (AF016914.1), Niigata, Japan (AB197937.1), Hawaii (EF125180.1), and Taiwan M2 (EU314803.1), with the coefficient divergence of 0.025. But, it has very distantly related to Hawaii 18-1 (EF125178.1) with a coefficient of 0.142. The results provide urgent information in supporting the native orchid's conservation and breeding efforts, locally and globally, including mitigating or controlling the viral infection and screening for the development of virus-free or resistant cultivars in the future.

The role of olive groves in the conservation of Mediterranean orchids

The role of olive groves in the conservation of Mediterranean orchids

Identification of fungal associates of the swamp helmet orchid (Corybas carsei), a threatened (nationally critical) species

ABSTRACT Corybas carsei is one of New Zealand’s most endangered orchids, with a single remaining population in the Whangamarino Wetland (North Island). Although orchid mycorrhizae have proved a critical aspect of orchid conservation globally, until now mycorrhizal fungi of C. carsei have not been identified or utilised for conservation. This study investigated fungal associates of C. carsei using three culture-based approaches: fungi grown directly from fragments of root tissue, from pelotons isolated from root-collars, and directly from macerated protocorm tissue. Fungi were cultured and identified as a diverse array of fungi through Sanger sequencing of the internal transcribed spacer region. This included the fungus Pleurotus purpureo-olivaceus (Basidiomycota; Agaricales), which belongs to a genus containing putative orchid mycorrhizal fungi, and the ericoid mycorrhizal fungus Oidiodendron eucalypti (Ascomycota; Leotiomycetes incertae sedis). No Rhizoctonia-like fungi, typical of orchid mycorrhizae, were found through any approach and fungi cultured in the present study likely represent endophytes, rather than mycorrhizal fungi. The potential of C. carsei having unculturable mycorrhizal associations, and the challenge this presents to conservation efforts, is discussed.

In vitro symbiotic seed germination in Vanda wightii, an endemic orchid species of Western Ghats, India supported by Ceratobasidiaceae isolates

Symbiotic seed germination for conservation and cultivation of orchids holds colossal merit asmycorrhizal fungus in its system improves their growth and adaptability. Symbiotic activity ishighly specific in some species, but in other cases the same fungus from one species is effective in aseries of related species. The present work describes inter-specific activity of three fungal isolatesfrom seedling root of Vanda thwaitesii to support seed germination and seedling growth of V.wightii, a closely related species from India. Among the three isolates, two designated as Wyd2 andIdk were identified as Ceratobasidium sp through sequencing of ITS1 and ITS4 regions. Oneisolate designated as Wyd1 did not clad with any described genera, but remained as an out-groupunder the family Ceratobasidiaceae. All the three isolates possessed binucleate hyphae producingellipsoidal, oval or barrel shaped monilioid cells and supported 80–95% seed germination,transforming 70–85% of them into protocorms in 30 days duration. Symbiotic seedlingdevelopment starting with the promeristem formation, first leaf development and second leafinitiation occurred in 95% of the protocorms in a time interval of 60 days compared to 90–120 daysthrough asymbiotic method. The fungal isolates from Vanda thwaitesii evaluated are provedeffective in V. wightii for its symbiotic seed germination and thus useful to mycorrhiza assistedconservation.

Effects of plant preservative mixture™ on in vitro germination of Dendrobium thyrsiflorum Rchb.f. and its application in orchid conservation

Effects of plant preservative mixture™ on in vitro germination of <i>Dendrobium thyrsiflorum</i> Rchb.f. and its application in orchid conservation

Isolation of Tulasnella spp. from Cultivated Paphiopedilum Orchids and Screening of Germination-Enhancing Fungi.

Ex situ conservation, an important way to increase the survival and sustainability of endangered species, is widely used in the conservation of endangered orchids. However, long-term ex situ conservation might affect the dominant group of orchid symbiotic fungi, which are crucial for orchid growth and reintroduction. This study investigated the culturable Tulasnella spp. associated with Paphiopedilum orchids after long-term greenhouse cultivation, and identified germination-enhancing isolates. A total of 44 Tulasnella isolates were obtained from the roots of 14 Paphiopedilum spp., and 29 of them were selected for phylogenetic analysis. They clustered mainly with Tulasnella deliquescens, Tulasnella calospora, Tulasnella bifrons, and Tulasnella irregularis, but included two potential new groups. Compared with published uncultured data, most of the isolates were grouped together with the reported types, and the dominant Tulasnella associated with P. armeniacum and P. micranthum could still be isolated after ten years of cultivation, most of which were the first isolation. In vitro symbiotic germination showed that certain root isolates could promote seed germination (e.g., parm152 isolated from P. armeniacum, Php12 from P. hirsutissimum, and prhi68 from P. rhizomatosum). These data indicated that the dominant Tulasnella types colonizing the roots of cultivated Paphiopedilum are stable over time, and germination-enhancing fungi colonizing the roots would benefit for seed reproduction after population reintroduction into the wild.

Spatial patterns, underlying drivers and conservation priorities of orchids in the central Himalaya

Understanding the primary drivers of species diversity patterns and identifying critical places for biodiversity protection are the two major concerns confronting the global conservation community. The Orchidaceae, which is one of the most diverse angiosperm families with over 30,000 species, is currently facing grave threats from habitat degradation, climate change, and a range of human-induced issues. However, the spatial patterns of orchid distribution and the factors influencing these patterns, both of which are crucial for developing successful orchid conservation plans, remain poorly understood. Here, using one of the most extensive distribution datasets of >500 orchid species in Nepal, we mapped the distribution of all, common, rare, epiphyte, and terrestrial species and identified important factors driving their patterns. We also assessed their protection gaps and identified key conservation regions. We discovered low spatial congruence between the diversity patterns of different groups, and the fundamental drivers underlying the richness pattern differed considerably. The key orchid conservation areas were primarily found in the mid-hills and highlands of central Nepal, with 62 % of these areas outside the protected area (PA) network. Our findings emphasize the importance of considering pollinator diversity and other climate factors when developing effective management plans to conserve orchids, as well as employing different strategies to conserve different life forms. A huge conservation gap in protecting orchids despite large PA coverage in Nepal indicates insufficiency of existing PA network in conserving plants. Therefore, our findings reiterates the need to consider plant conservation goals alongside animal conservation priorities in future conservation planning.

Terrestrial and epiphytic orchids exhibit different diversity and distribution patterns along an elevation gradient of Mt. Victoria, Myanmar

Orchids have been long fascinating biologists and ecologists because of their remarkable range of life history strategies, floral and vegetative morphology, pollination syndromes, and symbiotic fungi. However, the diversity and distribution patterns of orchids remain unclear in several regions, seriously hindering the understanding of orchid diversity and their maintenance mechanisms. In this study, species richness, abundance, and environmental conditions of epiphytic and terrestrial orchids were investigated along an elevation gradient of Mt. Victoria, Myanmar, ranging from 600 to 3000 m with 200-m intervals. A binary species-based network was structured between epiphytic orchids and their hosts to further address the effect of hosts on orchid distribution. In total, 94 orchid species were recorded, including 58 epiphytic and 36 terrestrial orchids. A hump-shaped pattern of epiphytic orchid richness occurred along the elevation gradient, with the highest richness at ca. 2200 m, whereas terrestrial orchid richness follows a monotonous decrease. Both elevation and slope significantly affected the species composition and diversity of epiphytic and terrestrial orchids, while terrestrial orchids were also affected by herb coverage. The network between epiphytic orchids and their hosts exhibited a low level of connectance, and significant nestedness with a high level of modularity and specialization. Interactions in the network were heterogeneously distributed among hosts, as Lithocarpus variolosus, Rhododendron arboretum, and Lyonia ovalifolia hosted a wide variety of orchid species and hence played an important role in maintaining the diversity pattern of epiphytic orchids, while the bulk of species exhibited few interactions. Twenty epiphytic orchids (such as Sunipia grandiflora, Liparis viridiflora, Porpax grandiflora and Liparis tsii), which were only attached to specific host species, may be exposed to a high risk of extinction with the intensification of human activities. This study provides basic data for the conservation and management of orchids in Mt. Victoria, Myanmar.

Evolutionary differences in gene loss and pseudogenization among mycoheterotrophic orchids in the tribe Vanilleae (subfamily Vanilloideae).

Galeola lindleyana is a mycoheterotrophic orchid belonging to the tribe Vanilleae within the subfamily Vanilloideae. In this study, the G. lindleyana plastome was assembled and annotated, and compared with other Vanilleae orchids, revealing the evolutionary variations between the photoautotrophic and mycoheterotrophic plastomes. The G. lindleyana plastome was found to include 32 protein-coding genes, 16 tRNA genes and four ribosomal RNA genes, including 11 pseudogenes. Almost all of the genes encoding photosynthesis have been lost physically or functionally, with the exception of six genes encoding ATP synthase and psaJ in photosystem I. The length of the G. lindleyana plastome has decreased to 100,749 bp, while still retaining its typical quadripartite structure. Compared with the photoautotrophic Vanilloideae plastomes, the inverted repeat (IR) regions and the large single copy (LSC) region of the mycoheterotrophic orchid's plastome have contracted, while the small single copy (SSC) region has expanded significantly. Moreover, the difference in length between the two ndhB genes was found to be 682 bp, with one of them spanning the IRb/SSC boundary. The Vanilloideae plastomes were varied in their structural organization, gene arrangement, and gene content. Even the Cyrtosia septentrionalis plastome which was found to be closest in length to the G. lindleyana plastome, differed in terms of its gene arrangement and gene content. In the LSC region, the psbA, psbK, atpA and psaB retained in the G. lindleyana plastome were missing in the C. septentrionalis plastome, while, the matK, rps16, and atpF were incomplete in the C. septentrionalis plastome, yet still complete in that of the G. lindleyana. Lastly, compared with the G. lindleyana plastome, a 15 kb region located in the SSC area between ndhB-rrn16S was found to be inverted in the C. septentrionalis plastome. These changes in gene content, gene arrangment and gene structure shed light on the polyphyletic evolution of photoautotrophic orchid plastomes to mycoheterotrophic orchid plastomes. Thus, this study's decoding of the mycoheterotrophic G. lindleyana plastome provides valuable resource data for future research and conservation of endangered orchids.

A novel method to produce massive seedlings via symbiotic seed germination in orchids.

Orchids produce large numbers of dust-like seeds that rely heavily on orchid mycorrhizal fungi (OMFs) for germination. Using OMFs to facilitate orchid proliferation is considered an effective method for orchid conservation but still presents challenges in practice. In this study, orchid seed-fungus complexes, in which orchid seeds and fungal mycelia were embedded together to form granules, were developed as platforms to facilitate seed germination and seedling production. Overall, seedlings were produced by seed-fungus complexes for five orchid species with large variations in the percentages of seedlings produced among species/treatments. For the different fungal treatments in Dendrobium officinale, Sebacinales LQ performed much better than the other fungal strains. At 90 days after sowing, 75.8±2.6% seedlings were produced in the LQ treatment, which was significantly higher than in the Tulasnella sp. JM (22.0±3.0%) and Tulasnella sp. TPYD-2 (5.3±1.0%) treatments, as well as in the LQ and TPYD-2 cocultured treatment (40.4±3.2%), while no seedlings were formed in the Tulasnella sp. SSCDO-5 or control treatments. For the other four orchid species, only one compatible fungus for each species was used, and the percentages of seedlings in epiphytic Dendrobium devonianum (67.2±2.9%) and D. nobile (38.9±2.8%) were much higher than those in terrestrial Paphiopedilum spicerianum (2.9±1.1%) and Arundina graminifolia (6.7±2.1%) at 90 days after sowing. Adding 1% polymer water-absorbent resin to the seed-fungus complexes of D. officinale seeds with fungal strain Sebacinales LQ significantly increased seedling formation, while other additional substances showed negative effects on seedling formation. For the storage of seed-fungus complexes, it is recommended to store the seed-fungus complexes in valve bags at room temperature for a short time and at a low temperature of 4°C for no more than 30 days. As a platform for symbiotic seed germination, the seed-fungus complex can facilitate seed germination, produce seedlings and support subsequent seedling growth, and its seedling productivity depends on seed germination characteristics, seed viability, and the efficiency of fungi. Seed-fungus complexes have great potential to be used as propagules in orchid conservation.

Orchid Micropropagation Using Conventional Semi-Solid and Temporary Immersion Systems: A Review.

Orchids, with their astonishingly stunning flowers, dominate the international floricultural market. They are considered prized assets for commercial applications in pharmaceutical and floricultural industries as they possess high therapeutic properties and superior ornamental values. The alarming depletion of orchid resources due to excessive unregulated commercial collection and mass habitat destruction makes orchid conservation measures an extreme priority. Conventional propagation methods cannot produce adequate number of orchids, which would meet the requirement of these ornamental plants for commercial and conservational purposes. In vitro orchid propagation using semi-solid media offers an outstanding prospect of rapidly producing quality plants on a large scale. However, the semi-solid (SS) system has shortcomings with low multiplication rates and high production costs. Orchid micropropagation using a temporary immersion system (TIS) overcomes the limitations of the SS system by reducing production costs and making scaleup and full automation possible for mass plant production. The current review highlights different aspects of in vitro orchid propagation using SS and TIS and their benefits and drawbacks on rapid plant generation.

Symbiotic Seed Germination and Seedling Development of Epidendrum geminiflorum Knuth from Ecuador

A greater understanding of the relationship between native orchids and their mycorrhizal symbionts is needed to ensure more effective orchid conservation strategies. A protocol for symbiotic seed germination and seedling development was developed for E. geminiflorum. Mature seeds were collected from a naturally occurring orchid population in Ecuador. Putative mycorrhizal fungi isolated from other native orchid species were used to screen their ability to facilitate germination and seedling development in vitro in either a 0/24 h or 12/12 h light/dark photoperiod at 20 °C. The mycorrhizal fungus Tulasnella calospora (UAMH 9824) isolated from Spiranthes brevilabris in Florida, USA, was also included in this study. Sterilization treatments using 0.3%, 0.5% sodium hypochlorite/ethanol or 2% calcium hypochlorite were tested for their effectiveness as sterilant and their subsequent effects on seed germination percentage. Effective surface seed sterilization was achieved with either 0.5% NaClO/ethanol or 2% calcium hypochlorite. However, significantly higher percentages of germinated embryos developed into protocorms when NaOCl solutions were used compared to the other treatments. Seed germination occurred in both photoperiods tested; however, delayed germination was observed under complete darkness. Seeds of E. geminiflorum germinated without fungal inoculation; however, co-culture with Tulasnella strains improved germination significantly. Seedling development was only observed when seeds were cultured in asymbiotic medium or co-cultured with T. caloscopa (UAMH 9824). Significantly longer seedlings were obtained when T. calospora was present in the culture compared with seedlings cultured in asymbiotic medium. The establishment of mycorrhizal associations was confirmed by the presence of pelotons in the roots of E. geminiflorum seedlings.

Advances in orchid research in East Macedonia (NE Greece) and the importance of current data in furthering our understanding of the orchids’ altitudinal requirements

High-quality data on species distribution and knowledge of species ecology are necessary pre-requisites for their effective conservation. In the European Union, a network of protected areas called the “Natura 2000 network” was set up to conserve the most valuable and threatened species. The Natura 2000 network was supposed to improve rare species conservation, but has it? In this paper, an analysis of data collected from 1 × 1 km grids on the distribution of orchids in East Macedonia (NE Greece) in two consecutive periods of time (before and after 2010), revealed the degree to which a larger data set (including both periods instead of only one) improved our knowledge of the distributions of species and whether the Natura 2000 network can be used as a basis for the conservation of the orchid flora in this area. When the data for the first period and cumulative data for both periods were compared, orchid species richness and density were very similar. However, comparison of the two datasets showed that more orchid taxa were recorded per grid in the first than the second period. However, based on the surveys in the second period, the knowledge on orchid distribution increased significantly. In particular, ten orchid taxa were recorded for the first time in East Macedonia during the second period and significantly more (54.79 % of the total number of species) were recorded. This resulted in a better understanding of their altitudinal requirements. It also confirmed that most of the orchid-rich grid cells in East Macedonia overlap with the Natura 2000 network, which highlights importance of Natura 2000 for orchid conservation.

Orchid diversity and distribution pattern in karst forests in eastern Yunnan Province, China

Global biodiversity loss and mass extinction of species have raised serious global concerns, especially in fragile ecosystems. Karst forest, a well-known fragile ecosystem, is served as a natural laboratory for biogeographical, ecological, evolutionary, and taxonomic research. However, species richness and distribution patterns in karst forests largely remain unclear. Orchidaceae has been regarded as the “flagship” group of plant diversity. In this study, we use Wanfengshan Nature Reserve in southeast Yunnan, China, as a model to determine the conservation status of orchids in the karst forest by conducting systematic field surveys in the past three years from 2019 to 2022. In total, we identified 78 orchid species in 35 genera in Wanfengshan Nature Reserve. The dominant species were Bulbophyllum andersonii, Eria coronaria, Nervilia mackinnonii and Paphiopedilum micranthum. Multiple life forms were also observed, including epiphyte (14.29%), facultative epiphyte (18.18%), lithophyte (23.38%), and terrestrial (44.15%). Orchid species richness showed a bimodal pattern varied with altitude, the higher richness was recorded at 1,500–1,600 and 1,200–1,300 ​m, while the minimum was below 1,100 ​m. Each independent hill is rich in orchid species including ‘endemic’ species. A total of 25 (33.8%) orchid species were considered threatened by the Redlist of Chinese Vascular Plants (Qin et al., 2017), including 3 CR species, 5 ​EN species and 17 VU species. We call for more research addressing the mechanisms of ecological adaption, mycorrhizal interactions, and pollination of orchids in karst forests, and effective ways for recovery and conservation of orchids.

Symbiotic Culture of Three Closely Related Dendrobium Species Reveals a Growth Bottleneck and Differences in Mycorrhizal Specificity at Early Developmental Stages

Mycorrhizal specificity, i.e., the range of fungi allowing mycorrhizal partnerships, differs among orchid species, but that at early developmental stages is unclear. We investigated whether mycorrhizal specificity during seed germination and seedling development differs among three Dendrobium species, D. officinale, D. okinawense and D. moniliforme, in vitro. Nine mycorrhizal fungal strains were obtained from the roots of these species and cultured with a seed of each Dendrobium species. Five to eight fungal strains stimulated seed germination, whereas one to four fungal isolates significantly promoted protocorm development in the three species. To evaluate effects on leafy seedling growth, seedlings obtained from asymbiotic culture were cultured with nine fungal isolates. D. officinale and D. okinawense showed specificity for a single Serendipitaceae or Tulasnellaceae isolate, whereas D. moniliforme exhibited specificity for three isolates of Serendipitaceae and Tulasnellaceae. Therefore, the three Dendrobium species had a growth bottleneck from seed germination to the protocorm stage, and mycorrhizal specificity of protocorm growth and seedling development in vitro varied among the species. Our findings imply divergent mycorrhizal specificity in Dendrobium species at early developmental stages. This study provides insights into the diversity of orchid mycorrhizal specificity, as well as valuable information for conservation of endangered orchids.

Orchid mycorrhiza: Isolation, culture, characterization and application

• This review states the isolation, culture, characterization and application of OMF. • Major bottlenecks of traditional identification of OMF and its elucidation are discussed. • States the application OMF for bio-hardening and growth promotion of seedlings. • Provides insights for mass cultivation and conservation of orchids. In nature all orchids develop a mutualistic association with specialized group of fungi called orchid mycorrhiza. In natural environment, orchids are exclusively reliant on mycorrhizal fungi for seed germination, establishment, growth and development. In the early developmental stages, all orchids are mycoheterotrophic, and in most cases the association subsists throughout their lifespan. The significance of orchid mycorrhizal fungi (OMF) for seed germination, nourishment, growth promotion, and survival has been established more than a century ago and tremendous advancements were made in recent decades. Till date, understanding the mode of interaction between orchids and mycorrhizal fungi and determining the architecture of interaction networks are major challenges in ecology and evolutionary biology. The development of molecular techniques has empowered us to unscramble the fungal diversity comprised in the symbiosis and has facilitated us to overcome the difficulties associated with the conventional identification of OMF and orchid-fungal interactions. In addition, the application of modern biotechnological approaches resolved many controversial issues of OMF. Recently, OMF are used for biological hardening and growth promotion of in vitro raised seedlings, early flowering and quality improvement of flowers, and diseases and pests management. The aim of this communication is to update and summarize orchid mycorrhizal research including isolation, culture, and characterization of OMF, understanding the mechanisms of orchid-fungus symbiosis, and application of OMF in seed germination, growth promotion, and survival of asymbiotically raised seedlings and conservation of orchids. This appraisal will convey valuable insights to orchidologists engaged in biology, propagation, and conservation of orchids.

Diversity and morphological relationship of orchid species (Orchidaceae) in Bangka Island, Indonesia

Abstract. Prayoga GI, Henri, Mustikarini ED, Anggyansyah. 2022. Diversity and morphological relationship of orchid species (Orchidaceae) in Bangka Island, Indonesia. Biodiversitas 23: 5323-5332. The population of orchid plants has suffered extinction due to the conversion of forest land functions. Efforts to preserve orchids can be carried out through exploration, identification and conservation activities. Diversity and morphological information are useful for resource management, conservation, hybridization, and genetic improvement of orchids. This research was to determine the diversity and relationship of orchids on Bangka Island based on morphological characters. This research was conducted in four districts in Bangka Island, namely Central Bangka, West Bangka, Bangka, and South Bangka. The research method used is a survey method with a convenience sampling technique. Observed data were analyzed descriptively and calculated for diversity index, evenness index, species richness index, and morphological relationship. Analysis of morphological relationship was done using UPGMA (Unweighted Pair Group Method with Arithmetic Mean). The results of the study found 17 species of orchids in Bangka Island i.e. Bulbophyllum subumbellatum, Podochilus microphyllus, Crepidium calophyllum, Phalaenopsis cornu-cervi, Cymbidium finlaysonianum, and Malaxix kobi. Bangka District found 10 species, namely Phalaenopsis sumatrana, Liparis rhombea, Bulbophyllum sp., Robiquieta spathulata, Liparis sp., Trichotosia velutina, Micropera collosa, Dendrobium aloifolium, Grammatophyllum speciosium, and Adenoncos major. Exploration in West Bangka District and South Bangka District only found the same orchid species, namely Acriopsis javanica. The orchid species on Bangka Island have moderate diversity, high evenness index, and low species richness index. The relationship of orchid species in Bangka Island based on morphological characters has 60% similarities which are divided into 9 clusters. Prevention of orchid population reduction on Bangka Island can be done by using in situ and ex-situ conservation methods. In addition, for the future development of orchids, crosses between orchids that have unique characters and distant morphological relationships can also be carried out to produce orchids for commercial purposes.

Spatial distribution and its limiting environmental factors of native orchid species diversity in the Beipan River Basin of Guizhou Province, China.

To understand the distribution of biodiversity and its determinants, particularly that of ecologically sensitive ones, has long been intriguing to the science community and will help formulate conservation strategies under future climate changes. To this end, we conducted extensive field surveys on the distribution of orchid flora in the Beipan River Basin in Guizhou Province, which is one of the biodiversity conservation priorities in China. The data we acquired, together with those published previously, were converted into orchid species richness for each of the 3km × 3km grid cells covering the study region. Redundancy analysis (RDA) and geographically weighted regression (GWR) were then applied to determine which of the 30 environmental factors are potentially critical for the spatial distribution of orchid flora we have observed. Despite a moderate spatial extent, we found that the Beipan River Basin harbors about 249 native orchid species belonging to 74 genera, equivalent to 14.5% of orchid flora of China. Orchid species richness in this area follows a descending gradient from the southeast to the northwest, 70.41% of its variation among grid cells can be explained by environmental factors and spatial variables, and spatial variables accounted for 63.90% of the spatial variation of orchid distribution, indicating that spatial variables played a dominant role in the distribution of wild Orchidaceae species richness. In addition, the main environmental driver is the mean temperature of the wettest quarter. Our study provides a good example for revealing the main drivers of orchid distribution characteristics and has a certain reference value for the development of orchid conservation strategies.