Coral Ba/Ca and Mn/Ca Ratios as Proxies of Precipitation and Terrestrial Input at the Eastern Offshore Area of Hainan Island

Geochemical ratios in coral reef skeletons could be used as proxies to reconstruct past climatological and environmental records in data-poor regions. Using a 103-year data set(1902 to 2005), the annual variations in Ba/Ca and Mn/Ca ratios of Porites lutea skeletons at an eastern offshore area of Hainan Island(19?12'28.4''N, 110?37'38.8''E) were analyzed using inductively coupled plasma-optic emission spectrometry(ICP-OES). The analysis results showed that Ba/Ca ratios varied from a minimum of 3.120 μmol mol^(-1) in 1903 to a maximum of 10.064 μmol mol^(-1) in 1944, with an average of 5.256 μmol mol^(-1). Mn/Ca ratios varied from 0.206 to 5.708 μmol mol^(-1) with an annual average of 1.234 μmol mol^(-1), with peak values in 2001, 1964 and 1932, that correlated with strong rainfall events caused by typhoons. Variation in Ba/Ca and Mn/Ca ratios were compared with available river discharge and precipitation records, providing insight into past climatological events. Human activities and their indirect effects could impact the strength of the relationship between Ba/Ca and Mn/Ca ratios and observed precipitation and terrestrial input in the future.

Ecological Function Value of Tropical Forests in the Central Mountainous Areas of Hainan Island

The integrated value of the ecological function of tropical forests in the central mountainous areas of Hainan Island was 33.064 8 billion yuan/a in 2010(soil improvement,soil consolidation,soil nutrient maintenance,water storage and moisture regulation,water purification,carbon sequestration,oxygen releasing,air purification,biodiversity conservation,eco-tourism),equivalent to 16.1%of GDP in Hainan Province this year(205.212 billion yuan).The tropical forests in the central mountainous areas of Hainan Island make great contribution to Hainan Island's ecology,and play an important role in maintaining the stability of the ecological environment in Hainan Island.Through the understanding of major ecological function value of tropical forests,it is necessary to make people cherish the tropical forests in the central ecological function conservation areas of Hainan Province,and spontaneously throw themselves into the ecological environment protection and construction,to promote the rapid and sustainable development of construction in Hainan Province as an international tourism island.

Discussion of Construction of Hainan International Tourism Island and Psychological Health of Tourism Area Residents

In the ongoing construction of an international tourism island in Hainan, China, the research on the mental health of the residents in the tourism destination is one of the main contents of the research on tourism development. Tourism area is the cell of Hainan International Tourism Island. The mental health service of the residents in the tourism area is an important part of the health work construction of the international tourism island and the basic way to realize the health care for everyone. Nowadays, people’s demand for mental health services is far greater than the current supply. In view of the current situation of the limited mental health services provided, we put forward higher requirements and directions for the future development of mental health services in tourist areas. It is planned to carry out the first large-scale publicity and education on mental health of residents in Hainan tourism area in China, and evaluate the effect;carry out a large-scale investigation on mental health of residents in the tourism area, and carry out professional intervention and treatment for patients with mental diseases. Finally, the mental health service network and service institutions covering the tourism areas of Hainan Province were established to provide scientific support for the harmonious and healthy development of the international tourism island in Hainan Province.

Spatial Structure and Development of Tourism Resources based on Point Pattern Analysis: A Case Study in Hainan Island, China

Tourism resources are the basic materials of tourism development, and they also provide the support for regional tourism spatial competition. The development of tourism depends on the degree to which tourism resources are utilized, and it is of great guiding significance for their development and utilization to study their spatial structure. Based on a large sample of data on tourism resources, and starting from the characteristics of multi-type,multi-level and multi-combination, this paper puts forward a framework and method for analyzing the spatial structure of tourism resources. Taking Hainan Island as an example, this paper describes the spatial structure of tourism resources in Hainan Island by using the method of point pattern analysis, identifies the tourism resource development zones, and puts forward some suggestions for the development of tourism resources. The results are as follows:(1) The characteristic scale of the spatial structure of tourism resources in Hainan Island is 30.5 km, and there are significant differences in the distributions of all kinds of tourism resources.(2) Through the spatial structure map of tourism resources, the tourism resource development zones are identified, including three tourist central city levels, “one horizontal and three vertical” tourist belts and four tourist combination areas.(3) By combing the distribution of tourism resources and the development zones in Hainan Island, the cross-border characteristics of the tourism resources and development zones are obvious. In order to give full play to the spatial combination and superposition effect of tourism resources, a change from a single isolated development mode to the overall combined development between regions is suggested. On the provincial scale, it is relatively accurate to describe the spatial structure of tourism resources for point data with a large sample size. However, the method of point pattern analysis can not only accurately describe the spatial structure of tourism resources, but it can also provide reference for other types of regional spatial analyses. The research results provide a scientific basis for the spatial planning of regional tourism resources and have practical significance for the development of regional tourism.

Differential expression analysis of coronary heart disease related genes in Hainan residents

Objective:To explore the correlation between coronary heart disease related genes and coronary heart disease in hospitalized patients in Hainan,and to provide theoretical basis for enriching the screening methods of high-risk groups of coronary heart disease in Hainan,and optimizing the prevention and treatment strategies.Methods:We select hospitalized patients born in Hainan and aged>30 years old from the Second Affiliated Hospital of Hainan Medical Unversity between January 1,2020 and June 30,2022,and divided the patients into the coronary heart disease group and the non-coronary heart disease group.PCR real-time fluorescence was used to measure gene expression,and Spearman correlation analysis was used to explore the correlation between gene expression and coronary heart disease.Results:A total of 55 whole blood samples were collected from non-coronary heart disease patients(including 26 women and 29 men),with a median age of 57 years,and 170 whole blood samples from coronary heart disease patients(including 44 women and 126 men),with a median age of 63.17.Apolipoprotein B gene(ApoB)was highly expressed in patients with coronary heart disease(P<0.001);AGT gene(P=0.0158),ApoE gene(P=0.0126),FGB gene(P=0.005),GNB gene(P=0.0151),MTFHR gene(P=0.0119),SEL gene(P=0.005),TNF gene(P=0.0298)were significantly overexpressed in the non-coronary heart disease group.The expression of NOS3 gene(P=0.3047),IL6 gene(P=0.7239),ACE gene(P=0.7852)was not different between the two groups.Coronary heart disease was negatively correlated with AGT gene(r=-0.163,P=0.011,P<0.05),positively correlated with APOB gene(r=0.75,P=0,P<0.01),negatively correlated with FGB gene(r=-0.163,P=0.011,P<0.05),negatively correlated with GNB gene(r=-0.165,P=0.011,P<0.05),negatively correlated withSEL gene(r=-0.171,P=0.007,P<0.01),negatively correlated with MHTHR gene(r=-0.210,P=0.001,P<0.01)and negatively correlated with TNF gene(r=-0.131,P=0.04,P<0.05),but coronary heart disease was not correlated with APOE,NOS3,ACE,IL6 and other genes(P>0.05).The ApoB gene of coronary heart disease was negatively correlated with triglyceride(r=-0.461,P=0),positively correlated with age(r=0.173,P=0.009),positively correlated with total cholesterol(r=0.499,P=0),negatively correlated with high-density lipoprotein(r=-0.181,P=0.007),and negatively correlated with low-density lipoprotein(r=-0.143,P=0.031).Conclusion:(1)The detection of apolipoprotein B gene expression may be used as an indicator for screening coronary heart disease in the coronary population in Hainan.It may increase the risk of coronary heart disease by affecting the level of total cholesterol.A larger sample of research is still needed.(2)AGT,ApoE,FGB,GNB,MTFHR,SELE,TNF and other genes may be the protective genes of non-coronary heart disease population in Hainan,and the high expression of these genes may reduce the occurrence of coronary heart disease,which still needs further study.

北部湾—雷琼地区新生代古海岸线重建与琼州海峡演化

古海岸线重建能为理解全球气候变化和海陆格局演变提供重要的线索。笔者等基于钻孔资料重建了北部湾—雷琼地区新生代以来古海岸线变迁与琼州海峡演变过程。结果表明,北部湾—雷州半岛—海南岛(雷琼地区)新生代经历了古近纪北部湾古湖、新近纪—早更新世早期古琼州海峡、早更新世晚期—晚更新世峡湾和全新世琼州海峡四个演化阶段。古近纪北部湾形成NEE向互不连通的断陷盆地并充填河—湖相沉积,渐新世晚期海水间歇性入侵北部湾古湖并连通孤立的断陷盆地;中新世早—中期(23.3~10.4 Ma)南海西北部海岸线快速后退,北部湾古湖演变为古琼州海峡,中新世晚期—上新世(10.4~2.58 Ma)海岸线继续后退形成宽阔的古琼州海峡,早更新世早期海退及火山喷发导致古琼州海峡萎缩;早更新世晚期—晚更新世气候频繁波动控制了峡湾与陆地的不断转化,而末次盛冰期大幅度海退直接导致北部湾—雷琼地区从海转陆;15~12 ka BP以来海岸线快速后退并在12~11 ka BP期间短暂停留,北部湾再次由陆转海,之后海平面继续上升,琼州海峡于11 ka BP自西向东完全打开,至6 ka BP海平面达到现今海平面以上2 m左右,现今海陆格局形成。

基于多光谱无人机的不同放牧策略对草地叶面积指数变化动态解析

针对海南岛耕地撂荒形成的草地无序放牧较为普遍的现象,以不同放牧方式(轮牧和连续放牧)、不同放牧强度(重度、中度和轻度)进行草地放牧试验,利用多光谱无人机和植被冠层分析仪,获取放牧期间日尺度草地叶面积指数(Leaf area index,LAI)信息,定量分析不同放牧策略对草地叶面积指数及牧牛行为变化的影响。研究结果表明:(1)中度放牧条件下的轮牧有利于草地LAI的提升。重度放牧时,轮牧和连续放牧草地的LAI上升的区域占草地总面积的比例分别为3.21%和12.65%;中度放牧时,轮牧和连续放牧草地的LAI上升的区域占草地总面积的比例分别为52.01%和25.83%;轻度放牧时,轮牧和连续放牧草地的LAI上升的区域占草地总面积的比例分别为61.02%和60.37%。(2)重度放牧条件下,牛的采食时间占比始终最高,随着采食时间占比的增加,草地LAI的减少量也随之增加,但当采食时间占比增加至70.88%~73.42%时,草地LAI的减少量逐渐降低。此时,草地叶面积指数下降到初始状态(第一天啃食前)的79.60%~79.90%,即牛的啃食量已经到达了草地LAI当日能够供给的极限,当超过这个极限时,草地可食用牧草大幅减少,牲畜个体采食竞争加剧,同时牛的啃食行为时间占比大大提高。研究结果有助于优选出牧场尺度下最佳的草畜管理措施,为热带草地畜牧系统的可持续发展从新的角度提供理论方法和决策支撑,助力国家生态文明试验区(海南)的建设。

Fluxes Footprint and Source Area of Rubber Plantation

[Objective] The paper was to analyze the quality of flux observation data of rubber plantation.[Method]Based on the FSAM model,footprint and flux source area were analyzed according to the continuous flux measurement with the open-path eddy covariance system on the 50 m tower of Danzhou Key Field Station of Observation and Research for Tropical Agricultural Resources and Environments,Ministry of Agriculture from Jan 1 to Jun 30,2010.[Result] Under unstable stratification,source areas were smaller than those under stable conditions,and source areas in the dormant season were larger than those in the growing season at the same level.In the main wind direction 130°-270°,the upwind range of source areas was in the magnitude of 100-758 m and vertical upwind range was-251-251 m at 80% level under unstable stratification in the growing season,and they were some large than those under the unstable stratification in the dormant season.The source areas of the upwind and vertical upwind ranges were 173-1 858,-534-534 m especially under stable stratification in the growing season,and they were smaller than those under stable stratification in the dormant season.In the other wind directions of 0°-130° and 270°-360°,the ranges were similar to those of the growing season in the prevailing wind direction under the same atmospheric conditions.[Conclusion] The study would lay a foundation for the future flux calculation and analysis.

基于MODIS数据的近20年海南岛叶面积指数时空变化及驱动力分析

叶面积指数(LAI)是重要的植被结构参数之一,在监测植被生长状态、评估生态系统健康以及制定环境保护政策等方面均具有重要价值。海南岛因其特殊的地理位置和气候条件,拥有丰富的植被资源,气候变化及人类活动对其影响不断加剧。因此,深入研究海南岛LAI的时空变化对于理解该地区植被状况具有重要参考意义。本研究基于2002—2022年的MOD15A2 LAI产品数据集和气象数据,利用Theil-Sen中值分析和Mann-Kendall趋势检验等方法,分析了海南岛LAI的时空分布变化及其对气候因子的响应。结果表明:1) 2002—2022年,海南岛LAI整体呈增长趋势,其中北部的增长趋势明显强于南部。这一现象与橡胶种植业的发展和南部地区旅游产业的兴起有关,表明LAI的变化与人类活动紧密相连。此外,海南岛的LAI分布呈现中部高、周边低的空间特征,与该地区的地势特征相一致。2) 2002—2022年海南岛LAI的平均变异系数为0.136,说明植被变化波动较小,表明其能保持生态平衡和一致性。3)在气候暖干化的背景下,温度上升对植被生长的促进作用存在饱和效应。海南岛北部地区的LAI与温度主要呈正相关,而南部地区主要呈负相关,降水的影响则与温度相反。以上结果表明,海南岛LAI的空间差异和时空变化主要受气候条件、地形和人类活动等多种因素的协同作用。本研究为海南岛植被保护、生态修复和气候适应性管理提供了科学依据。

地表基质调查的工作思路刍议:以海南岛为例

地表基质调查是当前自然资源调查监测体系中的全新领域,如何开展还缺乏统一的行动指南。在初步总结地表基质调查现状的基础上,提出从全国、大区、关键地段3个层次、分阶段组织开展全国地表基质调查的总体思路。结合海南岛地表基质发育的地质背景和赋存条件,就南方强风化区地表基质调查工作进行了实例分析。建议按照分区逐级调查与分类补充调查相结合、调查与研究并重的原则,开展海南岛全域—流域—重点区段不同层级地表基质调查。针对地表基质分类补充调查提出基础调查指标、特征调查指标和评价指标,强调热带强风化条件下海陆交互作用、表生地质作用和多圈层相互作用对地表基质的控制与影响。在查清海南岛地表基质现状和演化规律的基础上,开展地表基质的综合评价和区划,探索形成热带强风化区地表基质调查的技术方法。

海南岛中部山区暖云人工增雨催化试验物理效果分析

利用雷达、降水及探空资料对2015—2020年海南岛昌江霸王岭及五指山毛阳试验点的暖云吸湿性焰条催化试验在不同月份及天气系统影响下的增雨效果进行评估并通过选取典型个例研究催化过程的物理响应特征。结果表明:南海低压槽和华南沿海槽影响下的催化试验整体增雨正效果较明显,平均绝对增雨量均超过未催化组2.00 mm。7、8、9月暖云催化试验均能展现出不同程度的增雨正效果,其中8月催化试验平均绝对增雨量最高,达4.71 mm。海南岛2个试验点总催化样本平均绝对增雨量0.73 mm,平均相对增雨率13.52%,平均增水量39.73万m^(3)。由典型个例的物理检验中发现,催化后0.5 h是一个关键时刻,即催化云和对比云的几乎所有物理检验指标约在催化后0.5 h后拉开差距。

海口江东新区及邻区海岸线遥感监测及变迁特征分析

海岸线作为海洋与陆地的分界线,长期受到全球和区域环境变化的影响及人为活动的改造,是典型的生态脆弱带。通过开展海岸线变化特征及驱动因素的研究,掌握岸线利用现状及发展趋势,对海岸资源的开发、利用与保护具有重要意义。本文以海南省海口市江东新区及邻区为例,基于Landsat数据,提取了该区域1987—2018年8个时期的海岸线数据,并对其31年来的时空变化特征进行了系统分析。结果表明:(1)31年来江东新区及邻区海岸线时空变化显著,呈现出“减少—增长—稳定”的演变历史,岸线总长度净增加1.52 km。(2)岸线类型多样性降低,单一性较显著,其中人工岸线增加了61.83 km,增长速率为1.99 km/a;陆海格局变化特征复杂,整体呈向海扩张的态势。(3)20世纪末的快速发展对海岸线影响较大,港口码头与人工岛建设、围填养殖等活动使研究区生物岸线、砂质岸线等自然岸线受到改造。人为因素已成为海口市江东新区及邻区岸线不断变化的主要驱动力。

海南地区居民冠心病的相关基因表达差异性分析

目的:探索冠心病相关基因与海南地区住院患者冠心病之间的相关性,为丰富海南地区冠心病高危人群筛选手段,优化防治策略提供理论依据。方法:选取2020年1月1日~2022年6月30日到海南医学院第二附属医院就诊的住院病人,海南籍贯、年龄大于30岁的成年人,将病人分为冠心病组和非冠心病组。使用PCR实时荧光定量测基因表达量,运用Spearman相关性分析,探讨冠心病基因表达量与冠心病的相关性。结果:本研究共收集55位非冠心病人群全血样本(其中女性26名,男性29名),中位年龄为57岁,170位冠心病患者全血样本(其中女性44名,男性126名),中位年龄63.17。载脂蛋白B基因(ApoB)在冠心病组中显著高表达,P<0.0001;AGT基因(P=0.0158)、ApoE基因(P=0.0126)、FGB基因(P=0.005)、GNB基因(P=0.0151)、MTFHR基因(P=0.0119)、SELE基因(P=0.005)、TNF基因(P=0.0298)在非冠心病组显著高表达,NOS3基因(P=0.3047)、IL6基因(P=0.7239)、ACE基因(P=0.7852)在两组间的表达没有差异。冠心病与AGT基因呈负相关(r=−0.163,P=0.011,P<0.05)、APOB基因呈正相关(r=0.75,P=0,P<0.01)、FGB基因呈负相关(r=−0.163,P=0.011,P<0.05),GNB基因呈负相关(r=−0.165,P=0.011,P<0.05)、SELE基因呈负相关(r=−0.171,P=0.007,P<0.01)、MHTHR基因呈负相关(r=−0.210,P=0.001,P<0.01)、TNF基因呈负相关(r=−0.131,P=0.04,P<0.05),与APOE、NOS3、ACE、IL6等基因无相关性(P>0.05)。冠心病ApoB基因与甘油三酯呈负向相关,相关系数(r=−0.461,P=0.000),与年龄呈正相关,相关系数(r=0.173,P=0.009),与总胆固醇呈正相关,相关系数为(r=0.499,P=0.000),与高密度脂蛋白呈负相关,相关系数(r=−0.181,P=0.007),与低密度脂蛋白呈负相关,相关系数(r=−0.143,P=0.031)。结论:(1)载脂蛋白B基因表达检测可能作为海南地区冠人群冠心病筛查的一个指标,可能通过影响总胆固醇的水平增加冠心病的发病风险,仍需要更大样本的研究。(2)AGT、ApoE、FGB、GNB、MTFHR、SELE、TNF等基因可能是海南非冠心病人群的保护基因,这些基因的高表达可能会降低冠心病的发生,仍需进一步研究。

海南吊罗山一带1∶5万区调主要成果与进展

在海南岛东南部吊罗山-陵水县地区完成的1∶5万区域地质调查,通过地层学的综合研究,将区域地层划分为5个岩石地层单位(包括1个非正式地层单位);新获得9件侵入岩LA-ICP-MS锆石U-Pb年龄,为建立区域岩浆岩的时空格架和反演演化过程提供了新的资料;通过地球化学对比,首次将调查区内早白垩世保亭杂岩体确定为C型埃达克质岩石,为区内燕山晚期花岗岩找矿提供基础地质资料;首次发现和厘定出北东向芒三水库-长丰韧性变形带,并对变形带的岩石学特征、变形特征、运动学特征等进行了初步研究;新发现稀土矿床1处、矿化点10个,圈定4个成矿预测区,为下一步开展地质找矿提供了靶区;调查了区内地质灾害类型及分布特征,探讨了地质灾害的形成条件和诱发因素;对区内旅游资源进行了概略调查。

海南岛东部海域生物污损研究

于1989年10月—1990年6月，在位于海南岛东部海域的琼东和琼东南海区，分别布设W1（距岸68nmile）和J2（距岸23nmile）两个浮标站，进行生物污损的挂板试验。结果表明，该海域人工设施的生物污损主要由热带、亚热带海区常见种类引起，其中水螅、有柄蔓足类和牡蛎为上述两个站位的共同优势种；而无柄蔓足类主要分布在近岸的J2站。表层试板的生物污损程度远高于中、底层试板，且污损生物群落具有明显的垂直分带现象。

海南五指山地区花岗片麻岩锆石LA-ICP-MS U-Pb年代学特征及其地质意义

海南五指山地区出露大面积花岗片麻岩,且广泛发育NW向定向变形构造,表明经历了明显的动力变形变质作用;4个花岗片麻岩样品的LA-ICP-MS锆石U-Pb年代学测试数据表明它们形成于263～269 Ma,代表了中二叠世的一次重要地质构造热事件。结合前人研究成果认为,海南五指山地区263～269 Ma花岗片麻岩可能形成于华南与印支块体的碰撞拼合作用。这也暗示华南与印支的碰撞拼合可能始于263～269 Ma。

海南昌江县石灰岩地区轮叶戟群落特征研究

根据样方调查,分析了海南岛昌江县石灰岩地区轮叶戟Lasiococcacomberivar.pseudoverticillata群落的种类组成、外貌和结构特征,并就分析结果与其它地区进行了相关性分析和讨论。结果表明,在1800m2样地中,有维管植物164种,隶属于64科129属,其中以热带性分布属占明显优势,所占比例为94.87%。群落外貌终年常绿,生活型以高位芽为主,占76.07%,乔木多为单叶,叶型以中型叶为主,占70.73%。群落成层现象不明显;通过对优势种群的年龄结构分析显示,该群落处于增长状态,按照Raunkiaer的频度等级定律,A级频度值为71.95,其中有79种植物只出现于一个样方中。通过相关性分析显示,该地植物在属的区系成分上受气候的影响比基质的大,该群落所属的植被类型处于热带常绿季雨林向热带雨林演替的过渡阶段,并需用自然恢复的方式对植被进行恢复和保护。

2001-2014年海南岛植被覆盖时空变化特征

基于2001—2014年MODIS NDVI数据,采用趋势分析法、标准差法、Hurst指数法以及相关系数分析法研究了海南岛植被覆盖变化特征,结合气象数据及统计年鉴数据分析了气候变化及人类活动对植被覆盖变化的影响情况。研究表明:近14年海南岛NDVI呈显著增加趋势,增速为0.02/10a(p<0.01);空间分布上,植被覆盖呈由中心向四周递减的分布格局,高值区分布于中部山区市县;波动变化特征变现为中间波动小,四周波动大,高波动和较高波动区所占的比重为42%,高波动区主要集中于海口、琼海、万宁、东方、乐东等市县沿海区域;在趋势上,海南岛14年间植被覆盖变化以改善为主,轻度改善和中度改善所占比重为53.42%,其中22.65%的区域呈显著增加;Hurst指数表明研究区未来NDVI变化趋势呈持续性和反持续性的比重分别为57.21%和42.71%,其中持续改善和由退化转为改善的面积分别占11.15%和40.90%。海南岛植被生长年际变化受降水影响要强于气温,人类活动也是影响植被覆盖变化的重要因素。

海南吊罗山国家级自然保护区黄额闭壳龟种群密度调查

2005年7～9月(雨季)和2006年2～4月(旱季),对海南吊罗山国家级自然保护区海拔900～1100m地区的黄额闭壳龟Cuoragal binifrons种群密度进行了调查。在调查样区内根据植被类型随机选取6个调查样区,424个布笼点,6360个笼捕日,调查面积6·36km2,捕获黄额闭壳龟5只,其中,人工林中黄额闭壳龟的相对密度为0只/笼捕日,天然林中的相对密度为0·0009只/笼捕日;样带法计算调查区域黄额闭壳龟绝对种群密度为0·7862只/km2。由于人为猎捕和生境破坏等原因,黄额闭壳龟的野生种群呈岛屿状分布。

琼南沿海低山丘陵森林种子植物区系初步分析

在对海南岛南端沿海低山丘陵森林植被进行实地调查的基础上,研究了该地区种子植物区系。结果表明:该地区共有野生种子植物112科484属876种(包括变种);植物区系成分热带性质较强,热带性的科有78科,占总科数的69.64%,其中泛热带分布科有47科,占41.96%,是最大的类型。泛热带和热带亚洲成分的属占优势,各占非世界属总数的33.47%和19.62%;中国特有属有3属,分别为驼峰藤属(Merrillanthus)、海南椴属(Hainania)和乐东藤属(Chunechites),其分布中心为海南岛。热带成分的种占非世界种数的74.94%,明显处于优势地位;中国特有种有204种,占总种数的23.13%,其中海南特有种有78种。与琼北地区种子植物区系比较,两地种子植物区系在物种组成上有明显差异,主要是由于两地不同的气候和地质等自然地理环境因素的区域分异引起的。