Investigation on vascular plant resources and their diversity in Wuzhishan,China

Peiying Chen,Minli Run,b,Anhu Wng,Jingming Ji

a School of Traditional Chinese Materia Medica,Shenyang Pharmaceutical University,Shenyang 110016,China;b University of Michigan,Ann Arbor.930 N University Ave,Ann Arbor,MI 48109,USA

Abstract Wuzhishan,located in the central part of Hainan Island and characterized by undulating terrain and diverse vegetation,is rich in plants.In October 2020,field investigations were carried out by the 14th Shenyang Pharmaceutical University Chinese Medicine Resources Scientific Expedition Team.Through specimen collection and literature retrieval,the team collected and analyzed vascular plants,resulting in the identification of 455 species belonging to 328 genera in 145 families.The dominant families are Leguminosae,Malvaceae,Compositae,Rubiaceae,Lauraceae,Pteridaceae,and Polypodiaceae.The main dominant species were perennial herb,comprising 147 species,32.31% of the total.From the 367 species of medicinal vascular plants,the team screened and recorded 20 species of Li medicine according to indications of the medicinal use and the part of the plant used.As a result,the dominant families of vascular plants were similar to medicinal vascular plants,which means vascular plants is an important medicinal resource in Wuzhishan.Based on the investigation and research,further suggestions were made to strengthen the conservation and utilization of plant resources in Wuzhishan.

Keywords: plant resources;biodiversity;medicinal;protection and utilization;Li medicine;Hainan province

1 Introduction

Indigenous plant is usually the source of medicine,nutrient,and vitamin supplements for the local residents [1].Plant resources represented by vascular plants provide natural ingredients for many drugs.These active drug ingredients isolated by different preparation methods can be used to treat and prevent human diseases.Unfortunately,various factors affect the conservation of species diversity,genetic resources and sustainable development of the traditional Chinese medicine industry.Therefore,attention should be paid to the conservation of plant resources [2].

Wuzhishan,renowned for its abundant plant diversity,serves as a significant reservoir of medicinal plants,particularly for the indigenous population.The establishment of a nature reserve is one of the most effective approaches to safeguard biodiversity [3].Wuzhishan Provincial Nature Reserve was established in 1985 and upgraded to a national nature reserve in 2003 with the approval of the State Council.Among species present in the nature reserve,3 are listed as national class I key protected plants and 36 as class II.A total of 73 species of rare animals were found in Wuzhishan National Nature Reserve,accounting for 25.3% of the animal species in the area (Normative references: http://www.forestdata.cn/index.html).Some plants are relics of ancient species,which are valuable for plant research and should be protected.Li nationality,one of the most predominant minorities in Hainan,has lived in this area for more than 3,000 y [4].However,the traditional knowledge of medicinal plants employed by Li nationality in Hainan has not received enough attention.Therefore,the investigation and analysis of local vascular plant resources within the framework of ethnobotany proves to be particularly valuable,although only a limited number of international articles have dealt with this topic.

In order to promote the protection of plant species,field investigations and plant resource diversity analysis are necessary to reconcile biodiversity conservation.In 2020,the 14th Shenyang Pharmaceutical University Chinese Medicine Resources Scientific Expedition Team conducted a study on the plant species in Wuzhishan.This study was conducted through field investigation,specimen collection,literature retrieval and specimen verification.By examining and analyzing the pertinent information regarding plant resources,we aimed to gain insights into species composition,distribution,and utilization status in this area.The purpose is to provide scientific basis for the rational development and effective conservation decisions of vascular plant resources and ethnomedicinal plants in Wuzhishan.

2 Study area

Wuzhishan National Nature Reserve is located in the central mountainous area of Hainan Island,China,with geographical coordinates of 109°44 ‘ E and 18°84 ‘ N and an area of 133.86 ha (Fig.1) [5].The region belongs to the tropical monsoon climate zone,experiencing distinct dry and rainy seasons that result in abundant rainfall in summer and autumn.The annual average precipitation is about 2,390 mm,the relative humidity is 82.2%,and the annual temperature is 22.4 °C [6].It is characterized by uneven rainfall,rare cold wave,and slight temperature difference.The altitude ranges from 250 m in the low hills to 1,867 m at the peak of Wuzhishan,which is located in the middle of Hainan land.

Fig.1 Geographic location of the study area and the survey location

Wuzhishan Nature Reserve is home to a large area of pristine tropical rainforest,which is well preserved.The forest covers 86.7% of the reserve.Different natural vegetation types are distributed along the altitude gradient,including lowland rainforest,mountain rainforest,subalpine dwarf forest,shrubs of mountaintop,and secondary lowland rainforest with rich floristic diversity.

3 Ethnobotanical methods

The 14th Shenyang Pharmaceutical University Chinese Medicine Resources Scientific Expedition Team,along with relevant personnel of National Park of Hainan Tropical Rainforest and Guangdong Pharmaceutical University,carried out field expeditions in Wuzhishan Nature Reserve.Field investigations were conducted in Oct.2020,adopting the line survey method in representative fields.The sampling plots were limited to the main trekking trail up the mountain.The specimen were collected and the digital photos of medicinal plants were carefully taken.Detailed information such as collection location,acquisition time,and main morphological characteristics of plants were recorded.GPS logger was used to record latitude and longitude throughout the process.Plant specimens were identified in the campsite since it is difficult to identify them during the field trip.Identification of the vascular plants was carried out with referrence to Flora Republicae Popularis Sinicae (http://www.iplant.cn/frps),Illustrated Handbook of Plants in Tropical Rainforest Area of China: Plants of Hainan [7] and Flora of Guangdong (http://fgd.scbg.ac.cn).A list of vascular plant resources was established,with 455 species in total.From the list,vascular plants that can be used as medicine was screened out according to National Chinese herbal medicine compilation [8],Dictionary of Chinese ethnic medicine [9],Dictionary of modern medicine [10],and Chinese Materia Medica [11].The information of medicinal parts,efficacy,and main treatment were recorded with the reference to the above literature.In total,425 species were obtained,including 20 drugs of Li nationality.Finally,the identified specimens were deposited at library of Shenyang Pharmaceutical University,the analysis and evaluation of the vascular plant resource diversity were completed,and the improvement projects for exploitation and conversation were developed.

4 Results and discussion

4.1 Vascular plants species composition analysis in Wuzhishan

All data acquired from field expeditions were used for statistical analysis.In total,455 species of vascular plants belonging to 328 genera in 145 families were reported in Wuzhishan.Specifically,there are 22 families,41 genera and 80 species of pteridophytes,6 families,9 genera and 9 species of gymnosperms,and 117 families,278 genus and 366 species of angiosperms (Table 1).Angiosperms are the most abundant,accounting for 80.69%,84.76%,and 80.44% of the three levels of family,genus and species,respectively.In addition,the analysis and evaluation of the vascular plant resource diversity were completed,and the improvement projects for exploitation and conversation were developed.This shows that angiosperms have high adaptability to the environment so that they are the dominant plants in Wuzhishan.

Table 1 Vascular plant species in Wuzhishan

4.2 Vascular plant families and genera composition analysis in Wuzhishan

According to Table 1,there are 145 families of vascular plant species in Wuzhishan.After sorting and analysis,we have depicted the relationship between the number of families and the number of species.It can be seen from Fig.2 that 68 families,46.90% of the total,contain only 1 species,while 52 families,35.68% of the total,contain 2-5 species.Besides,18 families,which account for 12.41% of the total,contain 6-10 species.Among these families,Leguminosae,Malvaceae,Compositae,Rubiaceae,Lauraceae,Pteridaceae and Polypodiaceae contain more than 10 species.Although the 7 sections represent only 4.83% of the total families,the species they include represent 22.42% of the total species.This suggests that their ability to become dominant species may be related to their superior reproductive structure and strong environmental adaptability.

Fig.2 Species in different families of vascular plants in Wuzhishan

According to Table 1,there are 145 families of vascular plant species in Wuzhishan.After sorting and analysis,we have depicted the relationship between the number of families and the number of species.It can be seen from Fig.2 that 68 families,46.90% of the total,contain only 1 species,while 52 families,35.68% of the total,contain 2-5 species.Besides,18 families,which account for 12.41% of the total,contain 6-10 species.Among these families,Leguminosae,Malvaceae,Compositae,Rubiaceae,Lauraceae,Pteridaceae and Polypodiaceae contain more than 10 species.Although the 7 sections represent only 4.83% of the total families,the species they include represent 22.42% of the total species.This suggests that their ability to become dominant species may be related to their superior reproductive structure and strong environmental adaptability.

Statistical results indicated that out of 328 genera of vascular plant,252 genera that contain only 1 species have distinct advantages.The 252 genera account for the highest proportion of the total genera number (76.83%),and its species number is the highest (55.38% of the total) (Fig.3).There are 72 genera,accounting for 21.95% of the total genera number,contain 2-5 species.However,the proportion of the species in these 72 genera is greater,accounting for 37.58% of the total species number.Only 4 genera,accounting for 1.22% of the total genera number,contain 6-10 species.These 4 genera include Hibiscus,Ficus,Pteris,and Selaginella,and there is a total of 32 species in them.

Fig.3 Species in different genus of vascular plants in Wuzhishan

4.3 Vascular plants growth forms analysis in Wuzhishan

Table 2 shows that the main dominant species in Wuzhishan are perennial herbs,comprising 147 species and accounting for 32.31% of the total number of species.There are 127 species of shrubs and 109 species of trees,accounting for 27.91% and 23.96%,respectively.These three categories together make up a total of 84.18% of the overall species.Moreover,only 5 species of epiphytes were identified,namelyAntrophyum henryiHieron.,Antrophyum callifoliumBl.,Liparis delicatulaHook.f.,Asplenium nidusL.andDischidia chinensis.In general,perennial herb,shrubs and lianas are the subject of vascular plants in Wuzhishan.Perennial herbs and shrubs adapt well to unfavorable conditions such as frequent rainfall and short daylight hours under the shade of tall trees,due to their low bodies and dense distribution.

Table 2 Different growth forms of vascular plants in Wuzhishan

4.4 Medicinal vascular plants diversity analysis in Wuzhishan

Literature retrieval and information review were carried out to study the diversity analysis of the medicinal vascular plants in Wuzhishan.In total,425 species belonging to 308 genera in 135 families were identified,accounting for 93.10%,93.90%,and 93.41% of each category,respectively(Table 3).Among them,the main family of medical vascular plants are Rubiaceae (19),Leguminosae(18),Malvaceae (14),Pteridaceae (12),Asteraceae(12),and Lauraceae (12),which account for 14.07%,13.33%,10.37%,8.89%,8.89%,8.89% of the total family number respectively.The main genera are Pteris (7) and Ficus (7),which account for 2.27%of the total genera number,followed bySelaginella(6),which accounts for 1.95%.Additionally,the main living form of medicinal plants are herbs,with 182 species accounting for 42.82% of the total species number of medicinal vascular plants.

Table 3 Medicinal vascular plants in Wuzhishan

The fact that vascular plants are the main source of medicinal plants is possibly due to their wide distribution and accessibility.According to Zheng et al.,local residents in Hainan Island take woody plants (including shrubs and Arbors) as the main resources [12].The findings of this study showed that woody plants accounted for 50.58% of the total species,which is consistent with Zheng’s research results,indicating that the most abundant species are used most frequently.

According to the classification of medicinal parts,medicinal vascular plants in Wuzhishan can be divided into whole plants,roots and rhizomes,flowers,branches and leaves,fruits,and seeds.The findings indicate that the dominant medicinal part is the whole plant,with 136 species,comprising 38.64% of the total species of medicinal vascular plant (Table 4).The natural environment of Wuzhishan provides favorable conditions for the whole plants.Most medicinal vascular plants are widely used by local minorities,such as Li,in the treatment of various diarrhea,cough,and fracture.

Table 4 Medicinal parts of medicinal vascular plants in Wuzhishan

4.5 Li medicine resources in Wuzhishan

Li minority is one of the indigenous groups who have settled in Hainan Island [13].Li medicine has unique ethnic characteristics and plays a vital role in traditional medicine.It is assumed that the most frequently mentioned medicine plants are prevalent in the communities.Our results show that there are 20 species used as Li medicine,belonging to 17 families and 18 genera (Table 5).There are various medicinal parts,among which the whole plant is the most widely used medicine.In Li communities,mashed material and decoction are the most applied methods,and leaves,roots and underground parts are the most commonly used plant parts [12].

Table 5 Li medicine resources in Wuzhishan

The local environment,climate,lifestyle and productive activity have a significant impact on the traditional medicine of ethnic minorities [14].In the case of the Li minority,the use of certain plant species to treat hepatitis,gastroenteritis,colds,and skin problems (such as sores,abscesses,itching,and moniliasis) reflects their daily life and health challenges.Furthermore,the frequent mention of medicinal plants for treating rheumatism,arthritis,fractures,and external injuries suggests that these ailments are prevalent among the Li people,which is due to their lifestyle of raising animals in the mountains and searching for food in the tropical rainforest.The lifestyle and activities of the Li people often result in falls,abrasions,and cuts,and the extensive use of medicinal plants will produce a lot of medicinal plant waste [15].Therefore,exploring effective ways to utilize this waste is worthwhile.Li et al.indicated Li medicine was closed related to TCM,and Li traditional medicinal plant knowledge in Hainan was developed on the basis of TCM [1].Knowledge of the ethnic medicinal plant of these species enhances the protection of plant resources.

5 Conclusion

Wuzhishan,located in the middle of Hainan Island,is the birthplace of Changhua River and Wanquan River,two of the three major rivers of Hainan.With its complex terrain and geographical location,Wuzhishan has nurtured a variety of plant species and complex flora.Through our research,455 species,belonging to 328 genera in 145 families,were collected.Angiosperms dominate the three categories of family,genus,and species,indicating their highly adaptablility in Wuzhishan.More pteridophytes than gymnosperms were collected,indicating that the shady and humid environment provided by lush forests are beneficial to their growth.Leguminosae,Malvaceae,Compositae,Rubiaceae,Lauraceae,Pteridaceae and Polypodiaceae contain more than 10 species.Among the 328 genera of vascular plant,the most dominant species were found with 252 genera.In addition,perennial herb,shrubs,and lianas are the main vascular plant types in Wuzhishan.The results suggest that the largest number of medicinal plants,with 147 species,are used for the whole plant.Rubiaceae,Leguminosae,Malvaceae,Pteridaceae,Asteraceae,and Lauraceae are the major medicinal families.The analysis results are similar to the dominant families of local vascular plants,further suggesting that vascular plants are an important source of medicinal resources in Wuzhishan.Some of the herbs from Wuzhishan are widely used by Li to cure diseases and preserve health.

However,overgrazing,deforestation,and root excavation have seriously affected the habitats and vegetation of vascular plants.Unreasonable and unscientific development of tourism resources has greatly destroys the ecosystem in the region in Wuzhishan.Therefore,protecting the biome and habitats is an effective way we should take to address these problems.In our research,the inheritance of the local plant medicine was found to be facing an embarrassing situation: people who have expertise in the local ethnobotany are becoming scarce,which haven’t called for enough attention and support from local residents and the government.

Based on this,we strongly suggest that the capacity construction of the nature reserve be strengthened,protection measures implemented,regular research conducted and field work management activities be monitored.Besides,residents should raise awareness of plant protection and grasp ethnobotanical knowledge.Relevant organizations should address this serious problem and encourage people to document the traditional medicinal plant knowledge before its disappearance.The most important thing is to strengthen policy,law,and regulation construction.Local villagers should be banned from logging and hunting in the forests of the nature reserve.It is hoped that artificial destruction of plants can be reduced,and medicinal plants can be developed and utilized rationally.