The karst peak-cluster depression landscape is characterized by pronounced topographic and edaphic heterogeneity, resulting in a high degree of spatial variability in resource availability. Such a complex environmental mosaic influences plant functional traits and their adaptive strategies. However, the patterns of trait variation and their underlying environmental drivers in karst peak-cluster depressions remain poorly understood. In this study, we investigated a 15-ha forest dynamics plot in the Nonggang Nature Reserve, Guangxi. We used linear mixed models to partition variance, principal component analysis to examine trait covariation, and redundancy analysis combined with hierarchical partitioning to evaluate the effects of topographic and edaphic factors on leaf functional traits at the community, species and intraspecific levels. The results showed that trait variation was mainly driven by interspecific differences, with part of the variation attributable to evolutionary history. Morphological traits and physiological traits exhibited relatively higher intraspecific and interspecific variation, respectively. The trait covariation patterns revealed that several leaf chemical traits exhibited atypical modes of coordinated variation. The explanatory power of topographic and edaphic factors for trait variation differed among ecological levels, being highest at the species level, followed by the community and intraspecific levels. Among these, the soil carbon-to-nitrogen ratio and slope were identified as the main drivers of species-level variation. Overall, our findings reveal functional shifts in plant ecological strategies in complex karst landscapes and emphasize the differential influence of topographic-soil factors across hierarchical levels, providing empirical evidence for understanding plant adaptive mechanisms along multidimensional environmental gradients.

The genus Paphiopedilum (Orchidaceae) has high ornamental value due to its long flowering period, brilliant flower color, and peculiar floral morphology. Guangxi is the center of ecological diversity of Paphiopedilum, and therefore it is urgent to conduct rescue studies on the genetic resources and genetic structure of this genus in Guangxi. In this study, the genetic diversity of 39 populations from eight Paphiopedilum species in Guangxi was analyzed using ten selected EST-SSR primer pairs and fluorescent PCR amplification. The results show that genetic diversity varied among species, with large differences in expected heterozygosity (He). The highest genetic diversity was observed in P. barbigerum (I = 0.923; He = 0.480), while P. dianthum (I = 0.179; He = 0.098) showed the lowest diversity. From the genus perspective, molecular variance analysis (AMOVA) revealed that 57% of the genetic variation occurred among populations and 43% within populations, with inter-population variation being the main source of genetic variation. From a species perspective, genetic differentiation varied, with inter-individual differentiation ranging from 79% to 95%. The percentage of molecular variance indicated that genetic variation mainly occurred among individuals, which was the main source of total variation. According to the principle of maximum likelihood, the optimal K value was determined to be 6, and 760 Paphiopedilum samples were divided into six subgroups. The results of this study not only identify priority populations for conservation and establish a germplasm repository to preserve existing resources, but also provide references for research on asexual reproduction, seed propagation, and hybrid breeding of Paphiopedilum, thereby promoting the conservation and sustainable utilization of Paphiopedilum germplasm resources.

To analyze the diversity of photosynthetic carbon assimilation pathways and ecological adaptation characteristics in Dendrobium species, this study selected nine native Chinese Dendrobium species. A comprehensive approach was employed, integrating diurnal dynamics of net CO 2 exchange, carbon isotope ratios (δ 13 C), diurnal titratable acid accumulation (ΔH + ), leaf anatomical structure, and mesophyll succulent index (Sm). The results indicate: that Dendrobium parishii , Dendrobium aphyllum , and Dendrobium anosmum maintain positive net CO 2 exchange at night, with δ 13 C values exceeding − 16‰ and high nocturnal acid accumulation. Combined with their substantial leaf thickness (LT) and Sm, these species are classified as typical CAM plants; Dendrobium cariniferum , Dendrobium gibsonii , and Dendrobium hancockii exhibited no positive CO 2 exchange throughout the night, with δ 13 C values below − 26‰ and low ΔH + levels, demonstrating physiological characteristics consistent with the C 3 pathway; Additionally, Dendrobium linawianum , Dendrobium moschatum , and Dendrobium crystallinum exhibited weak nocturnal CO 2 exchange and moderate to low acid accumulation. However, their δ 13 C values remained within the C 3 range, indicating they are not stable CAM types but may exhibit plastic expression under specific environmental conditions, displaying characteristics of intermediate C 3 /CAM photosynthetic plants. The LT and SM exhibited partial overlap between C 3 /CAM and strictly C 3 species, highlighting the limitations of using morphological traits as sole diagnostic criteria. Correlation analyses further revealed that although LT was significantly associated with Nighttime Net CO 2 Exchange (NNEE) and δ 13 C, the Sm displayed only weak correlations with key physiological indicators. In contrast, NNEE, δ 13 C, and ΔH + were strongly aligned with one another, underscoring that structural characteristics can serve only as supplementary references, while reliable classification must depend on the coordinated variation of physiological metrics. Furthermore, the photosynthetic types of the examined Dendrobium species closely corresponded to moisture availability and light conditions in their native habitats, reflecting the ecological plasticity of their carbon-assimilation strategies. In summary, Dendrobium species exhibit remarkable diversity and environmental plasticity in their photosynthetic carbon assimilation strategies. This study, through multi-indicator integrated assessment, not only clarifies the photosynthetic types of different species but also provides important references for identifying photosynthetic carbon assimilation pathways and cultivating Dendrobium species.

A new species of Gesneriaceae, Petrocodoncurvitubus J.X.Wei, B.Pan & T.Ding, sp. nov. from Guangxi, China, is described and illustrated. The new species is morphologically similar to P.lui and P.tenuitubus, but can be easily distinguished by its elliptic to oblong-ovate leaves, corollas with two purple longitudinal stripes, and conical ovary.

Artificial forest (AF) is an effective means of human intervention in forest ecosystems, aiming at preventing issues, such as soil erosion and land desertification. However, owing to the characteristics of large-scale afforestation projects, which often involve vast spatial extents and extended temporal scales, AF usually exhibits complex distribution patterns. In such cases, traditional remote sensing methods usually fail to accurately monitor AF conditions. To address this issue, this study introduced deep learning (DL) algorithms to extract multilevel features from remote sensing images for AF mapping and employed image processing techniques to enhance AF boundary determination. Through integrating these two approaches, high-resolution mapping of AF parcels was generated for a typical region in the middle reach valley of the Yarlung Tsangpo River. In the validation phase, the extracted regions were compared with manually labeled datasets and three accuracy metrics were calculated to demonstrate the extraction performance of the model. The accuracy reached 90.12% with the intersection over union (IoU) of 88.42%, and the cross-entropy loss function is only 0.0218. Meanwhile, three sampling areas with different coverages were selected for comparison, and the extractions have better performance than the SAM model based on the comparison with the samples. The findings reveal that this method can segment each AF parcel into independent objects, and the results would be helpful for parcel-based researches.

Grasslands on the Qinghai-Tibet Plateau have been greening under climate change, but it is still debated whether this change strengthens resistance to drought or heightens ecosystem sensitivity to water stress. Here, we applied three indicators of drought impact-loss probability, loss intensity, and drought threshold-to assess how trends in the Normalized Difference Vegetation Index (NDVI) relate to drought sensitivity and influence grassland net primary productivity (NPP). We find that greening areas cover about 75% of the grassland area, concentrated in the mid to late growing season and more prominent at lower elevations. Despite elevated tolerance thresholds, greening regions experience more frequent and severe drought-related losses than browning areas, forming a pattern of high exposure and high response, which was most evident during the mid-season and at elevations between 3000 and 3500 m. A clear shift in drought impacts was observed with elevation, with the most pronounced transition occurring between 3500 and 4500 m, where ecosystem stability began to decline. In addition, we identified a nonlinear relationship between NDVI trends and drought impacts, with losses increasing at low greening rates but declining beyond a turning point around 0.12 to 0.15 × 10-2 year-1, suggesting that greening can either exacerbate or alleviate stress depending on its magnitude. While the role of soil moisture varied with season, limiting NPP early in the season and supporting it later. These findings suggest that greening does not uniformly mitigate drought impacts. Rather, its effects depend on greening intensity, phenological stage, and elevation.

Abies yuanbaoshanensis is an endemic endangered plant species in China. It is a global key protected coniferous tree species with critical academic value for phylogenetic and global climate change studies. Seven SSR primer pairs were used to amplify eight natural population and progeny. The results showed that a total of 29 alleles were amplified. The average Na, I, Ho, He, and F indices of the eight native populations were 3.125, 0.811, 0.413, 0.467, and 0.108, respectively. Compared with the natural population, the number of alleles, Shannon diversity index, and expected heterozygosity of the progeny population were higher than the average of the natural population. However, the number of effective alleles, observed heterozygosity, and inbreeding coefficient were lower than the average of the original population. SSR is usually a dominant marker with good stability and polymorphism in Mendelian inheritance. Priority should be given to LPF and LSP populations, which have high genetic diversity and private alleles. The results of SSR genetic information loci of natural populations and their progeny is helpful to study the genetic relationship between Abies yuanbaoshanensis and Abies from the molecular level, which lays a foundation for the classification of Abies and the construction of the core germplasm of Abies yuanbaoshanensis.

The genus Ottelia comprises approximately 21 submerged macrophyte species primarily found in tropical Africa and Southeast Asia. The classification of several Ottelia species as vulnerable under the criteria “A2c” in the China Species Red List emphasizes the urgency of establishing a credible taxonomy. The ambiguity in taxonomy and evolutionary history persists, primarily stemming from the absence of a robust phylogeny at the species level. The rapid progress in high-throughput sequencing technology has facilitated the retrieval of complete chloroplast (cp) genome sequences, offering a molecular foundation for conducting phylogenetic analyses. In this study, the entire cp genomes of five samples of four Ottelia species were sequenced. All five Ottelia samples exhibited a circular, quadripartite-structured molecule, with lengths ranging from 156,823 to 162,442 bp. A total of 75–88 simple sequence repeats (SSRs) in the cp genomes of the five Ottelia samples were observed, which could be used for species identification. A preliminary phylogenetic analysis revealed that O. fengshanensis, O. acuminata, and O. guanyangensis clustered with strong support (100 BS). O. acuminata var. jingxiensis was resolved as a sister to O. acuminata var. lunanensis (100 BS), and both were further found to be sisters to O. balansae. The widely distributed O. alismoides exhibited a close phylogenetic relationship as the sister taxon to all the Chinese endemic taxa, supported by robust values. Together, our thorough examination of the entire cp genomes of the five Ottelia samples provides eminent insights into reconstructing their phylogeny. Furthermore, it illuminates the evolutionary dynamics of the cp genome within the Ottelia genus.

Parashorea chinensis is a symbolic tree species in tropical seasonal rain forests in China. Its primeval habitat forest communities show clear adaptations to a tropical seasonal environment, and have the greatest diversity of tree species and the highest proportion of tropical flora, in China. Recently, a P. chinensis with a height of 72.4 m was discovered in the primeval forest of tropical karst peak cluster depression in Nonggang, Guangxi. This tree broke the record for the tallest tree in China's karst areas. Here we examine the properties of the forests that can support such remarkable trees, in order to update our understanding of the vegetation characteristics of tropical karst forests. We draw on four primeval forest community survey plots of P. chinensis in Nonggang, in order to summarize the characteristics of layer structure, species composition, plant areal types, leaf features, ecological habits, and dominant genera of these forest communities. The characteristics of the region around the tall tree were compared with those of other communities of P. chinensis in China. The results were as follows: (1) Giant trees exceeding 50 m in height are scattered across the canopy of the tallest tree's community. The continuous arbor and shrub layer can be divided into four layers, approximately 36.9 m, 25.6 m, 9.5 m, and 2.7 m high. There are 64 tree species, 24 shrub species, 31 vine species, 26 grass species, and 8 epiphyte species within the 2400 square meter plots. (2) The arbor layer is dominated by tropical flora plants such as P. chinensis and Dracontomelon duperreanum, karst endemic plants such as Excentrodendron tonkinense and Cephalomappa sinensis, and deciduous trees such as Garuga forrestii and Allospondias lakonensis. (3) Species of tropical flora account for 93.7% of the trees in the arbor layer, with species from tropical Asia (Indo-Malay) accounting for 65.6%. Mega-phanerophytes account for 15.6%; evergreen plants account for 85.9%; compound leaf plants account for 39.1%; leathery leaf plants account for 60.9%; and typical karst plants account for 28.1%. (4) The greatest similarity to the dominant tree forest is shown by Napo County in Guangxi. Maguan and Mengla Counties in Yunnan, Bama, Tianyang, and Dahua Counties in Guangxi are progressively less similar. These relationships indicate that the influence of tropical climate on community forest structure is greater than that of their geology. In summary, the primeval forest communities of P. chinensis in Nonggang thrive in the closed habitat environment of the tropical karst peaks cluster depressions, benefiting from the relatively humid and warm local climate. Characterized by the presence of iconic tropical giant trees such as P. chinensis and Dracontomelon duperreanum, these forests exhibit the intricate forest layers of a tropical seasonal rain forest. Due to the combined influence of the tropical northern margin's geographical location and karst landform, these communities' forest canopies contain a certain proportion of deciduous tree species, with relatively low proportions of mega-phanerophytes and epiphytic plants. The communities are rich in drought-resistant plants with features such as leathery leaves, microphyll leaves, compound leaves, and typical karst plants.

元宝山冷杉(Abies yuanbaoshanensis)是广西特有的珍稀濒危植物,为进一步探究元宝山冷杉的种实特征以及种子萌发特性,本研究分析了其果实和种子特征,采用发芽对照试验测定种子的萌发力.元宝山冷杉种实特征结果显示:球果长(9.44±1.10)cm,球果重(35.88±4.10)g,单果种子数531-711粒,球果重与单果种子数及单粒种子重之间存在显著的正相关关系;种子长度为(17.02±1.16)mm,宽度为(8.86±0.60)mm,厚度为(1.97±0.17)mm,种翅长为(6.99±0.66)mm,种翅宽为(5.30±0.55)mm,千粒重为(19.3±2.5)g;元宝山冷杉种子败育率较高,空粒占53.7％.元宝山冷杉种子萌发特性结果显示:种子最适萌发温度为25℃恒温,低于15℃时基本不萌发,在15-25℃变温下发芽势显著降低(P＜0.01);浸种有利于元宝山冷杉种子的萌发,浸种24 h的种子发芽率极显著高于浸种48 h的种子(P＜0.01);种翅对元宝山冷杉的种子萌发无抑制作用,但去翅后的种子发芽能力更强;纸床更适宜元宝山冷杉种子的萌发;低温贮藏可以保持元宝山冷杉种子的活性,延长种子寿命.因此,元宝山冷杉的种子在去翅条件下浸种24 h后放置在25℃恒温的纸床上更利于其萌发.

Cycas (family Cycadaceae), which spread throughout tropical and subtropical regions, is crucial in conservation biology. Due to subtle morphological variations between species, a solid species-level phylogeny for Cycas is lacking. In the present study, we assembled and analyzed the chloroplast genomes of six Cycas plants, including their genome structure, GC content, and nucleotide diversity. The Cycas chloroplast genome spans from 162,038 to 162,159 bp and contains 131 genes, including 86 protein-coding genes, 37 transfer RNA (tRNA) genes, and 8 ribosomal RNA (rRNA) genes. Through a comparative analysis, we found that the chloroplast genome of Cycas was highly conserved, as indicated by the contraction and expansion of the inverted repeat (IR) regions and sequence polymorphisms. In addition, several non-coding sites (psbK-psbI, petN-psbM, trnE-UUC-psbD, ndhC-trnM-CAU, and rpl32-trnP-GGG) showed significant variation. The utilization of phylogenetic analysis relying on protein-coding genes has substantiated the division of Cycas primarily into four groups. The application of these findings will prove valuable in evaluating genetic diversity and the phylogenetic connections among closely related species. Moreover, it will provide essential support for the advancement of wild germplasm resources.

Aims"Species"is the basic taxonomical unit in biology.The accuracy of endangered species delimitation largely determines the efficiency and conservation strategies.Abies beshanzuensis,A.ziyuanensis and A.dayuanensis,a group of endangered firs endemic to the subtropical region of China,have extremely small populations and controversial taxonomy.According to morphological differences and geographical distribution,A.dayuanensis has been considered as the synonym of A.ziyuanensis,whereas A.ziyuanensis is currently treated as a variety of A.beshanzuensis.However,no genetic evidence has been provided to test this classification hypothesis. Methods We performed target enrichment sequencing on 23 individuals from eight extant populations and obtained 805 single nucleotide polymorphic sites from 60 single-copy nuclear genes for population genetic analyses. Important findings Results of population genetic structure and demographic history analyses showed that this endangered fir group has diverged into two lineages corresponding to A.beshanzuensis and A.ziyuanensis.Abies ziyuanensis first diverged from the common ancestor of A.beshanzuensis and A.dayuanensis,the latter two split apart later and more closely related,forming the other lineage.The genetic diversity is low within these populations.Strong genetic differentiation was found among populations(fixation index,FST = 0.083-0.208).Gene flow is not detected after lineages split,probably because of the fragmented habitats which blocked effective genetic exchanges among populations.Ecological niche comparison showed that the average annual temperature and the temperature of the coldest quarter were significantly higher in the habitats of these endangered firs compared to those of non-threatened firs in East Asia.Therefore,we inferred that global warming is likely to push this group of endangered firs to the edge of extinction.According to the significant population differentiation,we provide genetic evidence that A.dayuanensis is a synonym of A.beshanzuensis,and resurrect A.ziyuanensis as a separate species.Based on the niche comparison results,we highlight the necessity to carry out ex suit conservation in the Hengduan Mountains and the Qingling-Bashan Mountains and conduct in suit regeneration.

Aspidistra albovillosa, a new species of Asparagaceae from Guangxi, southern China, is described and illustrated. The new species is similar to A. ovatifolia, but differs by the appendages at the base of the perianth lobes are purplish red, sometimes white and slightly rolled upwards at apex, tube adaxially with white villous densely, stigma upper surface yellowish white, slightly undulate and 6 (or 8) lobed at margin. The new species is currently known only from the Karst areas in central Guangxi. Colour plates of the two similar species and line drawing are provided for comparison.

Tree mortality plays a vital role in forest dynamics and contributes to species coexistence and community assembly. However, the mechanisms that control tree mortality are poorly understood, particularly in species-rich tropical forests. Size-dependent abiotic constraints and biotic interactions act simultaneously to cause tree mortality in natural forests. However, these drivers are often studied independently, which can limit our understanding of how they interact to affect tree mortality in natural forests. We employed a hierarchical Bayesian logistic regression modeling approach to quantify the simultaneous effects of tree size, topography, neighborhoods, and their interactions on tree mortality in a 15-ha fully mapped tropical karst seasonal rainforest in Southern China. Of the variables tested, tree size exhibited the most consistent and strongest negative effect on tree mortality, while topography and neighborhood competition were of secondary importance. Neighbors, particularly heterospecific neighbors, had a facilitative effect on lowering mortality, while only several species showed conspecific negative density dependent on mortality. The topographical wetness index had a significant positive effect on tree mortality. Size-dependent and neighborhood competition-induced tree mortality was stronger for shade-intolerant than for shade-tolerant species, and the size-dependent mortality was the strongest for shrub species among the three growth forms. Our results indicated that the size-dependent effect was the dominant cause of tree mortality; however, neighbors, particularly heterospecific neighbors, had a facilitative effect on lowering tree mortality. Furthermore, the relative importance of these mechanisms for tree mortality differed within life-history strategies guilds. Our study highlighted the value of simultaneously considering the individual and interactive effects of multiple mechanisms toward understanding the dynamics and coexistence of highly diverse metacommunities in harsh environments.

Petrocodon anoectochilus F. Wen & B. Pan, a new species of Gesneriaceae from Guangxi and Guizhou in southwestern China, is described and illustrated. Although the leaf morphology of this new species looks similar to that of P. coriaceifolius (Y. G. Wei) Y. G. Wei & Mich. Möller and P. pseudocoriaceifolius Yan Liu & W. B. Xu, this remarkable new species can be easily distinguished from all other species of Petrocodon s.l. (the two above-mentioned species included) by the shape and color of its memorable corolla. Because of its restricted distribution and threatened environment, the current conservation status of this species should be assessed temporarily as “Endangered.”

森林凋落物是森林生态系统极其重要的组成部分,关系着森林生态系统的物质循环和养分平衡.然而,有关异质性自然森林生态系统中生物与非生物因子对凋落物凋落量的影响机制还存在较大争议.本文以广西弄岗15ha森林动态监测样地中设置的90个凋落物收集器所收集的凋落叶为研究对象,选取2013-2018年连续6年的凋落叶数据探讨了森林叶凋落量的时空动态,旨在深入了解该地区森林生态系统的物质循环过程及凋落量的影响因子.结果 显示:2013-2018年的年均叶凋落量为4,099.44 kg/ha,标准误为232.34,变异系数为0.15,这表明不同年际间叶凋落量存在明显差异;不同年际间叶凋落量的节律性变化为双峰型、三峰型或多峰型,说明不同年份的叶凋落量存在明显的节律性差异,但总体而言高峰期主要出现在每年的春季(3-4月)和秋季(8-10月);生态因子对叶凋落量年际动态存在显著影响,其累计解释率为69.3％,其中海拔对叶凋落量的影响最强,解释率为46.5％;而生物因子如胸径变异系数、单位面积胸高断面积之和和物种丰富度则对叶凋落量的影响较弱.多年的连续监测表明,喀斯特季节性雨林不同年际间叶片的凋落量和节律性存在显著差异,而非生物因子,如海拔是形成叶凋落量空间变异的主要因素.

Litter is a vital component of ecosystem functionality, which is inherently linked to net primary productivity and global biogeochemical cycles. To better understand the drivers that modify net primary productivity, we need to disentangle the processes that underly changes in the generation of litter. We employed structural equation models (SEMs) to test for the direct and indirect effects of biodiversity, the stand structural attributes, and abiotic drivers on annual litter production in a tropical karst seasonal rainforest. For this study, annual litter production was evaluated over a five-year period in 90 permanent sample litter traps in a dynamic 15-ha long-term forest plot in Southern China. For each circular plot stand (with central litter traps) we quantified biodiversity, structural variations, basal area, and growth rate, which are important for net primary productivity. The four best-fit SEMs with different metrics of biodiversity for the paths between biodiversity, structural attributes, abiotic drivers, and annual litter production had a similar goodness of fit to the data. They accounted for 42.7-47.8% of the variation in annual litter production, 4.7-16.8% of the variation in stand-level growth rate, 29.3% of the variation in stand-level basal area, 8.2-13.2% of the variation in stand structural variation, and 4.4-6.5% of the variation in biodiversity. Although biodiversity had a positive effect on annual litter production through direct or indirect effects via the stand-level growth rate, abiotic drivers had the strongest impacts on annual litter production. We also found that the structural attributes of the stands had positive effects on the annual litter production; however, only the stand-level growth rate had significant consistently positive effects on annual litter production in the four best-fit SEMs. These results implied that annual litter production is most strongly driven by abiotic factors, followed by stand structural attributes and biodiversity. Theoretically, our study supports that niche differentiation and facilitation might enhance productivity; however, this enhanced capacity is primarily contingent on how abiotic variations are controlled in the sampling of natural karst forest systems. Biodiversity and the conservation of specific habitats should therefore be a key component in the management of forest resources, forest conservation, and sustainability.

Mitreola liui sp. nov., a new species from Chongqing, China, is described and illustrated. This species is close to M. petiolatoides in morphological characters. Both of them have terete stem, lateral veins 4-6 pairs, stamens 5, inserted at corolla tube base but are distinguished by perennial, leaves blade long elliptic to oblanceolate, apex acute, the flower with narrow-triangular bracts. The key to the species of Mitreola in China is provided.

Abies yuanbaoshanensis is critically endangered and endemic to Guangxi province of China, with no more than 900 surviving individuals. In this study, we reported the complete chloroplast (cp) genome of A. yuanbaoshanensis. The complete chloroplast genome is 121897?bp in size. In total, 112 genes were identified, including 74 protein-coding genes, 34tRNA genes, and four rRNA genes. In phylogenetic analysis, the tree supported the monophyly of the genus Abies. The complete plastome of A. yuanbaoshanensis will provide potential genetic resources for further conservation and evolutionary studies of this highly endangered species.

[目的]研究北热带喀斯特季节性雨林优势木本植物种群生态位特征,了解群落内各种群对资源的利用状况及生态适应性,为生物多样性保护及退化生态系统的植被恢复提供参考.[方法]在对弄岗 1 5 hm2北热带喀斯特季节性雨林进行样方划分及植被调查的基础上,以375 个20 m×20 m的样方作为不同的资源位,以各样方物种重要值作为生态位计测的状态指标,运用 Levins和 Pianka公式计算、分析样地内 30 个优势种群的生态位宽度和生态位重叠度.[结果]生态位宽度较大的种群为苹婆、广西牡荆、茎花山柚、假玉桂和日本五月茶等,生态位宽度分别为 207.04,195.01,176.88,142.05 和 126.23;生态位宽度较小的是三角车、肥牛树、对叶榕、米扬噎和中国无忧花等,分别为 37.95,35.79,33.83,25.87 和 15.76;重要值排序靠前的闭花木、蚬木、海南椴和劲直刺桐的生态位宽度居于中间位置,生态位宽度为 107.54,77.54,113.48,95.12.生态位重叠值等于 1 的种对有0 对;生态位重叠值大于或等于 0.5、小于 1 的种对有 20对,占总种对数的 4.6%,生态位重叠值大于 0 小于 0.5 的种对有401 对,占 92.2%;生态位重叠度等于 0 的种对有 14 对,占种对数 3.2%.[结论]喀斯特季节性雨林中适应性强、分布范围广的种群,生态位宽度较大,且绝大部分种对的生态位重叠度较小.苹婆、金丝李和茎花山柚等生态位宽度比较大,资源利用和环境适应能力较强、而且兼具生态和经济价值,在岩溶石漠化地区进行植被恢复时应作为优先考虑物种.要建立完整的石漠化地区植被恢复参照系统,应在不同岩溶气候带建立不同演替阶段的天然植被监测样地,分析其环境条件、群落结构及 种间关系等.在针对某个地区某个恢复阶段进行植被恢复设计时,应参照该地区这个恢复阶段的天然群落,选择生态位宽度大的物种作为先锋种,选择生态位重叠度较小的物种作为伴生种.