Nghiên cứu tính đa dạng thực vật làm cơ sở cho công tác bảo tồn tại khu bảo tồn thiên nhiên bắc hướng hóa, tỉnh quảng trị TT TIENG ANH

MINISTRY OF EDUCATION & TRAINING MINISTRY OF AGRICULTURE & RURAL DEVELOPMENT VIETNAM NATIONAL UNIVERSITY OF FORESTRY *********** HA VAN HOAN RESEARCH ON PLANT DIVERSITY TO PROPOSE THE MEASURES OF CONSERVATION IN BAC HUONG HOA NATURAL RESERVE, QUANG QRI PROVINCE Major: Forest Resources Management Code: 9620211 SUMMARY OF DOCTORAL DISSERTATION HA NOI, 2022 The dissertation was completed in Vietnam National University of Forestry – Xuan Mai Town, Chuong My District, Ha Noi Capital Supervisor: Dr Do Thi Xuyen Ass Prof Dr Vu Quang Nam Reviewer 1: Reviewer 2: Reviewer 3: The dissertation had been defended before the Doctoral Elevation Dissertation Council at Institute level in Vietnam National University of Forestry – Xuân Mai Town, Chuong My District, Ha Noi City, in , 2022 The dissertation can be found at: - National Library of Vietnam - Library of Vietnam National University of Forestry LIST OF PUBLISHED ARTICLES Do Thi Xuyen, Nguyen Anh Duc, Dang Minh Tu, Ha Van Hoan (2015), State of the fern in Bac Huong Hoa Reserver, Quang Tri province Proceedings of the 6th national scientific conference on ecology and biological resources, pp 409-417 Agriculture publishing house, Ha noi Do Thi Xuyen, Vu Xuan Phuong, Ha Van Hoan, Nguyen Anh Duc (2016), Genus Opithandra B L Burtt an Species Opithandra dinghushensis W T Wang as New records for the flora of Vietnam from Bac Huong Hoa Nature Reserve, Quang Tri Province VNU Journal of Science: Natural Sciences and Technology, Vol 32, No 1S (2016) 142-146 Ha Van Hoan, Nguyen Tan Hieu, Do Thi Xuyen, Nguyen Anh Duc (2017), State of threatened plants in Bac Huong Hoa Natural Reserve, Quang Tri province Proceedings of the 7th national scientific conference on ecology and biological resources, pp 724730 Agriculture publishing house, Ha noi Ha Van Hoan, Do Thi Xuyen, Nguyen Anh Duc, La Thi Thuy, Kieu Cam Nhung, Vu Quang Nam (2019), Conservation status of Gymnosperm in Bac Huong Hoa Natural Reserrver, Quang Tri province Journal of Agriculture & Rural Development, N0 24 2019 134-139 Ha Van Hoan, Nguyen Tan Hieu, Do Van Hai, Tran The Bach, Bui Hong Quang, Duong Thi Hoan, Le Ngoc Han, Tran Duc Binh, Vu Anh Thuong, La Thi Thuy, Do Thi Xuyen, 2021 A new occurrence species Myrtaceae of the flora of Vietnam from Bac Huong Hoa Natural Reserver, Quang Tri province Journal of Agriculture & Rural Development N0 413 130-134 INTRODUCTION The urgency of the research issue Research on forest flora is one of the most important tasks for the study and conservation of biodiversity The study of flora helps people to understand clearly the composition and properties of flora in each place and each region, in order to build a model of exploitation, use, sustainable development and protection of natural resources Bac Huong Hoa Nature Reserve located in the north of Huong Hoa District, Quang Tri Province, far from 50 km to the north-west of Dong Ha city It covers an area of 23,456.7 hectares, most of the area is located in the west of the Truong Son mountain range, in which is the highest terrain of Quang Tri province with two peaks, Sa Mu peak (1550 m) and Voi Mep peak (1700 m) It has a rich flora and typical ecosystem of the Central Truong Son mountainous region and a place to store precious, rare and endangered plant genetic resources Currently, the buffer zone of the Bac Huong Hoa Nature Reserve is inhabited by the Van Kieu ethnic group and the Kinh Their livelihood is also heavily dependent on the forest However, in the Bac Huong Hoa Nature Reserve, activities such as clearing for cultivation, logging and Non - wood product, hunting wild animals and encroaching on forest land are still taking place That has reduced biodiversity in general and reduced plant diversity, forest resources in particular, and affected the landscape and living environment At present, Bac Huong Hoa Nature Reserve has only a few studies being carried out, and no studies have been carried out to find solutions to conserve plant diversity For that reason, the author carried out the topic: " Research on plant diversity to propose the measures of conservation in Bac Huong Hoa Natural Reserve, Quang Qri province" The purpose General objective: Assessing the diversity vascular plant in order to propose the measures of conservation in Bac Huong Hoa Natural Reserve, Quang Tri province Specific objectives: - To complement and complete the list of vascular plants in Bac Huong Hoa Natural Reserve, Quang Tri province - To assess the diversity vascular plant about flora and vegetations in Bac Huong Hoa Natural Reserve, Quang Tri province - To give out the measures of conservation in Bac Huong Hoa Natural Reserve, Quang Tri province Scientific and practical significance - Scientific significance + To provide the detailed data on plant diversity in Bac Huong Hoa Nature Reserve, Quang Tri province + To give out the solutions for management and conservation of plant diversity in Bac Huong Hoa, Quang Tri province - Practical significance: The project is a document contributing to the management, use and sustainable development of plant resources in Bac Huong Hoa Nature Reserve, Quang Tri province New points of the thesis - Made a check list of vascular plant species in Bac Huong Hoa Natural Reserve includes 1494 species/subspecies of 703 genera, 168 families of phyla (Lycopodiophyta, Equisetophyta, Polypodiophyta, Pinophyta and Magnoliophyta) Among them: + Gived out 02 new recordeds for the Flora of Vietnam as Opithandra dinghushanensis W T Wang (Gesneriaceae) and Syzygium fluviatile (Hemsley) Merrill & L M Perry (Myrtaceae) + Gived out distribution area in Vietnam of 02 species, which have not recorgnised in Vietnam's document before as Strobilanthes hossei (Acanthaceae), Murdannia loriformis (Hassk.) R S Rao & Kammathy (Commelinaceae) - Described and assessed all kinds of vegetation in Bac Huong Hoa Natural Reserve - Cause of decline plant diversity and solutions for management and conservation: give out direct sources and indirect sources of decline plant diversity in Bac Huong Hoa Natural Reserve The study also suggested groups of solution for management and conservation of plant diversity in Bac Huong Hoa Natural Reserve Thesis structure The thesis consists of 145 pages, 21 tables, 33 figures and is structured into the following main parts: Introduction (3 pages); Chapter 1: Overview of the research situation (30 pages); Chapter 2: Objects, content, research methods (15 pages); Chapter 3: Research results and discussion (85 pages); Conclusion and recommendations (3 pages); References (8 pages) and appendices Chapter OVERVIEW OF THE RESEARCH SITUATION 1.1 Perspectives on biodiversity In the International Convention for the Conservation of Biodiversity, it is defined: “Biodiversity is the distinctiveness, diversity in structure, function and other characteristics between living organisms from all sources including ecosystems on the land and aquatic ecosystems” According to Nguyen Nghia Thin (2005), biodiversity is also defined as follows: “Biodiversity is the collection of all life resources on our planet, including the total number of plant and animal species, the diversity and abundance in them individual species, the diversity of ecosystems in different ecological communities, or the aggregation of species living in different parts of the world with different circumstances” 1.2 Some studies on vascular plants in the world 1.2.1 Some studies on vegetation in the world There are many different authors giving their own theories on forest classification for the assessment of ecological diversity Each theory offers its own classification methods according to the purpose of the author such as A F Schimper (1903), Champion (1936), A Aubréville (1949), Schimithusen (1959), UNESCO (1973), … 1.2.2 Some studies on plants in the world Research on plant taxonomy in the world must include authors such as: Hutchinson (1975), R K Brummitt (1992), Heywood (1997) Some typical works of some countries close to Vietnam such as Flora of Malaysia (1948-1972), Flora of Thailand (1970-2012), Flora of India (1873-1890), Flora of China, including Chinese and English versions (1968-2000) (1994-2013), Flora of Taiwan (1993-2000), Flora of Hong Kong (2000-2009) … Some studies on plant life forms in the world such as Raunkiaer, 1934 1.3 Some studies on vascular plants in Việt Nam 1.3.1 Some studies on vegetation The researching on forest vegetation and forest structure, it is worth noting a number of works such as Tran Ngu Phuong (1970), M Schmid (1974), Thai Van Trung (1999), Nguyen Nghia Thin (2004) Research on plant diversity in some National parks (NPs) or Vietnam's Natural Reserver has had many works such as Phung Ngoc Lan, Nguyen Nghia Thin, Nguyen Ba Thu in Cuc Phuong National Park (1997); Nguyen Nghia Thin & Nguyen Thanh Nhan in Pu Mat National Park (2004); Nguyen Nghia Thin et al in Bach Ma National Park (2003); Nguyen Nghia Thin and Dang Quyet Chien in Na Hang Nature Reserve (2006); Nguyen Nghia Thin et al in Hoang Lien National Park (2008); Tran Minh Hoi et al in Xuan Son National Park (2008),… 1.3.2 Some studies on plants in the world Vietnam has a number of authors studying botany such as Loureiro (1793), Pierre (1880-1888), Aubréville (1960-2001) Most notably, the series "Illustration Flora of Vietnam" by Pham Hoang Ho (19992000), descriptive statistics 11,611 species, belonging to 3,179 genera, 295 families and phyla In 2001, 2003, 2005, a collective of authors from the Center for Research on Natural Resources and Environment in Vietnam National University – Hanoi, the Institute of Ecology and Biological Resources - Vietnam Academy of Science and Technology have statisticed as 11,238 species of higher vascular plants, belonging to 2,435 genera and 327 families And addition, many books are written on plant families in Vietnam such as the Annonaceae by Nguyen Tien Ban (2000), the Myrsinaceae of Tran Thi Kim Lien (2002), the Cyperaceae of Nguyen Khac Khoi (2002), genus Dendrobium of Duong Duc Huyen (2017), These are important documents as a basis for the assessment of plant taxonomic diversity in Vietnam Some studies in NRs or NPs have also been carried out such as Cuc Phuong National Park by Phung Ngoc Lan et al (1997), Na Hang Nature Reserve by Nguyen Nghia Thin et al (2006) 1.4 Some studies on vascular plants in Bac Huong Hoa Nature Reserve 1.4.1 Some studies on vegetation In 2011, the Forest Information Advisory Center - Institute of Forest Investigation and Planning collaborated with Quang Tri Forest Protection Department to study and identify vegetation types, the results were given about the structure of the Natural Reserve with rich forests, medium forest and secondary forest after shifting cultivation Khong Trung (2014) based on the UNESCO 1973 vegetation classification framework, identified 16 types of vegetation in the BHH Nature Reserve The author used a belt of 500 m to divide the study area into elevation belts, which are below 500m high and 500-1600m high 1.4.2 Some studies on flora According to the research results on biodiversity in Bac Huong Hoa in 1999, Quang Tri Forest Protection Department in collaboration with Birdlife Vietnam to establish Bac Huong Hoa Nature Reserve, which has assessed the forest resources of Bac Huong Hoa It gave out Bac Huong Hoa Nature Reserve with high biodiversity This result has built the "List of plant species in Bac Huong Hoa Nature Reserve, Quang Tri province" with 578 species In 2009, the Quang Tri Forest Protection Department and the Forest Investigation and Planning Institute conducted an additional investigation The survey results showed that the flora area has 920 species of higher vascular plants belonging to 518 genera and 130 families 1.5 Natural and Social characteristics of Bac Huong Hoa Nature Reserve 1.5.1 Natural condition 1.5.1.1 Location: Bac Huong Hoa Bac Nature Reserve is about 50km from the center of Huong Hoa district to the north of Quang Tri province, located on the West branch of Ho Chi Minh road The North borders with Quang Binh province, the West borders with Laos People's Democratic Republic, the East and the South borders with communes of Huong Hoa and Vinh Linh districts The entire conservation area is limited by geographical coordinates: From 16 43'22'' to 16 59'55'' North latitude; From 106 33'00'' to 106 47'03'' East longitude 1.5.1.2 Topography, geomorphology 1.5.1.3 Climate 1.5.1.4 Hydrology 1.5.1.5 Some features of vegetation 1.5.2 Social and economic conditions 1.5.2.1 Residential: Bac Huong Hoa Nature Reserve is located in communes with ethnic groups living together, Van Kieu and Kinh, of which Van Kieu people account for 68.3% 1.5.2.2 Education and Health: Annually, over 95% of students are mobilized to class at the right age The work of universalization of lower secondary education and illiteracy eradication is currently continuing to be consolidated and expanded, mobilizing subjects to attend classes and maintain classes after illiteracy eradication Chapter OBJECTS, CONTENT AND RESEARCH METHODS 2.1 Object and site of the study The object of the study is the forest state, the vascular plant in Bac Huong Hoa Nature Reserve, Quang Tri province The main study period is years: from 2015-2019 2.2 The content 2.2.1 Flora diversity in Bac Huong Hoa Nature Reserve 2.2.1.1 Identifying species and building a list of higher vascular plants 2.2.1.2 Taxonomic diversity of plants 2.2.1.3 Diversity of plant life forms 2.2.1.4 Diversity of botanical geographical factors 2.2.1.5 Evaluation of diversity in the use value of plants 2.2.1.6 Diversity of rare genetic resources 2.2.2 Diversity of vegetation types in Bac Huong Hoa Nature Reserve 2.2.2.1 System of vegetation types 2.2.2.2 Description of taxa in the vegetation system 2.2.3 Proposing solutions to conserve plant diversity in Bac Huong Hoa Nature Reserve 2.2.3.1 Causes of loss of plant diversity 2.2.3.2 Advantages in the conservation of plant diversity 2.2.3.3 Difficulties in the conservation of plant diversity 2.2.3.4 Proposing solutions to conserve plant diversity 2.3 Methods 2.3.1 Approach Vietnam is located in an area with a tropical climate and extremely rich and diverse forest ecosystems Due to the impact of nature as well as of humans, these ecosystems are always changing Therefore, it is necessary to investigate and evaluate the diversity of forest plants, mainly vascular plants, to measures to manage and conserve them In order to reflect the diversity of vascular plant taxa groups, it is necessary to collect samples of vascular plants distributed in the reserve The established study routes must be fully representative of Psilotophyta Lycopodiophyta Equisetophyta Polypodiophyta Pinophyta Magnoliophyta 10 153 14 0.67 0.07 10.24 0.94 57 669 63 0.02 0.54 0.02 6.31 0.59 Reserve/ Vietnam (%) 17.54 50 22.87 22.22 1316 88.09 9.812 92.52 13.14 Total 1494 100 10.605 100 14.09 * Source: Nguyen Nghia Thin, 1997 Comparison of the number of plant species of Bac Huong Hoa Nature Reserve and Da Krong Nature Reserve (the Reserve area is 37,681 ha, the same protected area in Quang Tri province) shows that the results are almost similar Accordingly, DaKrong Nature Reserve has recorded 1,452 species of plants with 28 species listed in the Vietnam Red Book and the IUCN list According to the list of vascular plant species in DaKrong Nature Reserve, many species present in DaKrong are also present in Bac Huong Hoa Nature Reserve However, this result is not close to reality because many new taxa announced in DaKrong Nature Reserve have not been added to the list in recent years According to the current assessment, the number of precious and rare species in DaKrong Nature Reserve may be much higher than previously recorded Through the comparison of species of these two floras, it was found that 891 species are similar The closeness of the two floras Da Krong and Bac Huong Hoa is shown by the Sorensen index as follows: S = x 891/( 1.452+1494) = 60.49 The number of species: the number of species of some Protected areas and National Parks can be summarized as follows:  Dakrong Nature Reserve has recorded 1,452 species  Bach Ma National Park (2003) has 1649 species belonging to 753 genera of 190 families  Na Hang Nature Reserve (2006), with 1162 species, 604 genera, 150 families  Xuan Son National Park (2008) with 1217 species, 680 genera, 180 families  Hoang Lien National Park (2008) has 2,024 species belonging to 771 genera, 200 families The distribution of taxa is not only shown in the phyla, the number of species per area as quite different, but also in the classes of the Magnoliophyta, which has the largest number of species among the phyla of the plant kingdom The distribution of taxons in the phylum Magnoliophyta shows that the class Magnoliopsida dominates (about 80% of the total number of families, genera and species of the whole phylum) Class Liliopsida accounted for a much lower proportion The ratio of species, families and genera between the Magnoliopsida and Liliopsida classes is 4.14; 4.96 and 3.89 Table 3.6 Distribution of taxa in Magnoliophyta Class Magnoliopsida (M) Liliopsida (L) Total Ratio (M/L) family Quan % tity 114 23 137 genus Quan % tity species Quan % tity 83.21 498 79.55 1060 80.55 16.79 128 20.45 256 19.45 100 626 100 1316 100 4.96 3.89 4.14 The diversity index of taxa: The family index is 8.61 (on average, each family has more than species); The genus index is 2.13 (on average, each genus has more than species); The genus-to-family index is 4.18 (on average, each family has more than genera) 3.1.2.2 Diversity at family level of plants in Bac Huong Hoa Nature Reserve Among 168 plant families, there are 33 families with only species, 18 families with only species The number of families with the number of species more than 10 is 44 families, especially 17 families with the largest number of species (with a large number of species 20) The total of 10 families with the largest number of species include 215 genera (accounting for 30.58%) and 453 species (accounting for 30.32%) Table 3.6 Statistics of the 10 richest families in flora of Bac Huong Hoa Nature Reserve Species Genera TT Name of families Quan % Qua % tity ntity Orchidaceae 91 6.09 44 6.26 Rubiaceae 65 4.35 31 4.41 Euphorbiaceae 60 4.02 24 3.41 Asteraceae 47 3.15 27 3.84 Fabaceae 36 2.41 20 2.85 Poaceae 35 2.34 25 3.56 Moraceae 34 2.28 1.0 Fagaceae 29 1.94 0.43 Lauraceae 29 1.94 14 1.99 10 Lamiaceae 27 1.81 20 2.85 Total of 10 families 453 30.32 30.58 (5.95%) 215 3.1.2.3 Diversity at genus level of flora of Bac Huong Hoa Nature Reserve The total of 10 most diverse genera (1.42% of the total number of genera) (with the number of species from or more) have 132 species, accounting for 8.84% of the total number of species of the whole flora Table 3.7 Statistics of the richest genera in flora of Bac Huong Hoa Nature Reserve TT Genus Ficus Ardisia Lithocarpus Family Moraceae Myrsinaceae Fagaceae Species Quanti % ty 22 17 17 1.47 1.14 1.14 10 Asplenium Aspleniaceae Pteris Pteridaceae Elaeocarpus Elaeocarpaceae Blumea Asteraceae Syzygium Myrtaceae Dendobium Orchidaceea Mallotus Euphorbiaceae Total the 10 richest genera (1.42%) 13 12 12 10 10 10 132 0.87 0.80 0.80 0.67 0.67 0.67 0.60 8.84 3.1.3 Diversity of plant life forms Applying the life form classification system of Raunkiear (1934) with modification of N.N Thin (2007) when analyzing the life form spectrum of the flora of Bac Huong Hoa Nature Reserve, the total number of species in Bac Huong Hoa Nature Reserve is 1494 species The author has identified the life form of 1487 species, and 07 species are unknown The results showed that the group of Phanerophytes (Ph) dominated with the rate of 79.02%, followed by the group of Hemicryptophytes (Hm) with the rate of 9.08%; group of plants Chamaephytes (Ch) rate at least 2.76% From the obtained results, the author simulates the life form spectrum for this flora as follows: SB = 79.02 Ph + 2.76 Ch + 9.08 Hm + 3.36 Cr + 5.78 Th Table 3.8 Statistics of life forms of species in flora of Bac Huong Hoa Nature Reserve Symbol Life form Quantity % Ph Phanerophytes 1175 79.02 Ch Chamaephytes 41 2.76 Hm Hemicryptophytes 135 9.08 Cr Cryptophytes 50 3.36 Th Therophytes 86 5.78 Total 1487 100 Analysis of the Phanerophytes (Ph) group showed that the Nano phanerophytes group (Na) accounted for the highest proportion of 24.77% of the total species in the Ph life form, followed by the Herbaces phanerophytes group (Hp) accounting for the highest percentage, taking ratio of 13.96% Ph, the group of Meso phanerophytes (Me) accounted for 15.66% of Ph, and built a spectrum of life forms for the Phanerophytes Ph = 6.21 Mg + 15.66 Me + 18.89 Mi + 24.77 Na + 6.38 Ep + 1.28 Suc + 12.00 Lp + 13.96 Hp+ 0.85 Pp 3.1.4 Diversity of botanical geographical factors Based on the geographical factors framework of Nguyen Nghia Thin (1997, 2005, 2007), the study on the geographical factors distribution of 1494 species of vascular plants in the flora of Bac Huong Hoa Nature Reserve was conducted It can be seen that, in terms of basic structure, tropical elements in general have a very large proportion Details are as follows: - Tropical element: 87.34% (highest)  The Asian tropical factor accounts for the largest proportion of 63.38%  Endemic factor with 13.25%,  Old tropical elements with 8.10%,  Inter-tropical factor 2.61%; - Temperate factors account for 9.37% - Global factor (accounting for 0.67%) (lowest) - Cultivation plant factor (accounting for 1.27%) 3.1.5 Diversity in the use value of plants Base on the collected data, among of the 1494 species recorded, the author has listed 1058 plant species with use value, accounting for 70.82% of the species of flora, some species have only one value, but there are many species that have 2-3 or more values such as both for wood and medicine or for wood, for fruit and medicine The total number of uses is up to 1797 times The group of medicinal plants accounted for the highest proportion with 746 species, accounting for 49.93% of the total species Other values account for a lower proportion such as: species for edible products have 303 species, accounting for 20.28%; for wood: 236 species, accounting for 15.80%; for ornamental purposes: 150 species, accounting for 10.04%, 3.1.6 Diversity of rare genetic resources Table 3.18 Threatened and near-threatened species and conservation status according to the criteria CR EN VU LR DD IA IIA Total Endanger level Vietnam's Red Data 13 26 40 Book (2007) Decree No 06 114 119 (2019) IUCN (2020) 24 35 17 31 24 114 171* Total There are all 171 species of vascular plants that need to be conserved according to the evaluation criteria of the Vietnam's Red Data Book (2007), Decree No 06/2019/ND-CP of the Government (2019), IUCN (2020) (accounting for 11,447% of the total number of species of the flora) In which, according to the Vietnam's Red Data Book (2007), there are 40 species of trees, Decree 06 has 119 species and the IUCN list has 35 species 3.2 Diversity of vegetation types in Bac Huong Hoa Nature Reserve, Quang Tri province 3.2.1 System of vegetation types According to the vegetation classification system of T V Trung (1999) and N N Thin (2004), the types of vegetation in Bac Huong Hoa Nature Reserve are classified into the following classification following: I Group of vegetation types at the altitude under 800 m I.1 Closed evergreen forest I.1.1 Forest in the soil mountains I.1.1.1 Closed evergreen tropical rain forest with broadleaf trees I.2 Woodland forest I.2.1 Woodland forest with evergreen broadleaf trees recovering from shifting cultivation or exploitation I.2.2 Woodland forest with mixed broadleaf wood and Bamboo I.3 Shrub type I.3.1 Evergreen shrubland type I.4 Grassland I.4.1 Grassland less than m high, mainly monocotyledonous plants II Group of vegetation types at the altitudes above 800 m II.1 Closed evergreen forest II.1.1 Forests on soil mountains and limestone mountains II.1.1.1 Closed evergreen sub-tropical rain forest with broadleaf trees II.1.1.2 Closed evergreen sub-tropical rain forest mixed coniferous and broadleaf trees forest II.2 Woodland forest II.2.1 Woodland forest with evergreen broadleaf trees recovering from shifting cultivation or exploitation II.2.2 Woodland forest with mixed broadleaf wood and Bamboo II.3 Shrub type II.3.1 Evergreen shrubland type II.4 Grassland II.4.1 Grassland less than m high, mainly monocotyledonous plants 3.2.2 Description of taxa in the vegetation system 3.2.2.1 Closed evergreen tropical rain forest with broadleaf trees under 800 m This type of forest is scattered on the low altitude belt, usually below 800 m, occupies a small area, about 5,662.9 ha, due to the exploitation or invasion of the forest in the past Only a part remains of Huong Viet and Huong Son communes The forest structure has (3)-4 layers with the canopy layer often not forming clearly The canopy layer is not clear, with a height of about 14-18 m, especially some individuals up to 22 m high, mainly species of the genus Lithocarpus spp or Castanopsis spp., some species of the Lauraceae family 3.2.2.2 Woodland forest with evergreen broadleaf trees recovering from shifting cultivation or exploitation This type of forest is usually distributed around the Nature Reserver, the area is quite large, about 6,995.2 It can be clearly seen on the road to Sa Mu peak, in areas near villages of Huong Lap, Huong Son and Huong Linh communes, there are many in Ban Cup (Huong Lap) area, or along the stream upstream of Ban Pin area (Huong Linh), Trang-Ta Puong village (Huong Viet) This forest type has originated from the tropical moist closed evergreen forest, due to shifting cultivation activities as well as burning forest, which have lost the vegetation layer of primary forest, and then many years the forest regeneration The tree layer of this forest type is mainly mixed, light-loving, fast-growing timbertree species These timbertree species has low use value, strongly invasive, and clearly dominate in the forest plant communities In addition, among the dominant species of this forest, there are some species that are remnants of the primary forest that have the ability to regenerate and recover well under the forest canopy such as Pometia pinnata Forst & Forst., Streblus asper Lour., Streblus laxiflorus (Hutch.) Corn., Castanopsis chinensis (Spreng) Hance, some species in Ficus spp., Diospyros spp 3.2.2.3 Woodland forest with mixed broadleaf wood and Bamboo This forest type is about 6.34 ha, scattered in NRs such as Huong Viet, Huong Son and Huong Lap communes, making area along streams such as Ra Ly, So Lit, Thon Ho Stream (Huong Son commune) This type of forest is derived from the tropical moist evergreen closed forest and these is a direct consequence of the process of shifting cultivation or overexploitation Tinbertrees no longer have the ability to regenerate and dominate as before They give space to many species developing of Bamboo such as Nua or Sat After the Bamboo as Nua or Sat growing, it often spreads rapidly due to underground stem development, in many places making a closed forest Bamboo, almost the composition of bamboo species accounts for almost complete dominance, densely canopy At that time, the number of individual tree species decreased Bamboo includes many species such as Bambusa balcooa Roxb, Bambusa bambos, Bambusa blumeana Schult, Bambusa procera or Neohouzeaua dullooa 3.2.2.4 Shrub type This vegetation type is more degraded than the above types of vegetation, about 3,592 They distributed mainly on strongly degraded lands due to erosion, long-term shifting cultivation and cattle grazing, scattered in the area of Bac Huong Hoa Nature Reserve, on small areas near the Station Forest Ranger Huong Lap, adjacent to the forest ranger's management area of Huong Hoa district, Huong Son commune area (the road to Pin, the road to Tria (Huong Son), Trang - Ta Puong villages (Huong Viet commune), After deforestation and shifting cultivation, the topsoil is strongly eroded, becomes dry, tight, has poor moisture holding capacity, shallow soil layer, bony, only suitable for shrub species On these land areas appeared barren shrublands with poor species composition, the height of shrub species is usually 1.5-2.5(4) m, mainly shrubs and small trees, light-loving vine, light-loving herbaceous, droughttolerant species, with able to grow and develop on nutrient-poor, dry soil Regeneration of woody species is almost absent or only a few major species Liquidambar formosana Hance, Trema orientalis 3.2.2.5 Grassland: Like secondary shrubs, the condition of the grasslands is the result of long-term shifting cultivation and grazing of local people In the study area, this type forest is scattered throughout the Nature Reserve, but the area is small, about 3,524 Grasslands under m high, mainly plants of the class Liliopsida such as sedge (Cyperaceae), grass (Poaceae) 3.2.2.6 Closed evergreen sub-tropical rain forest with broadleaf trees on soil mountains and limestone mountains: This type of forest is usually distributed at altitudes above 800 m, occupies a large area of the Nature Reserver, and is found mainly in Huong Phung commune (Sa Mu peak area, where the office of NR is currently located); the area of Pa Thien mountain, Voi Mep (Huong Son commune), about 199.7 Coverage is up to 60-70%, especially in some areas it can be even higher The forests in these places are less affected, and still to keep basically their primary nature character The forest has a distinct 5-layers structure This forest compared with the same type of forest at an altitude of under 800 m, the number of timbertree species is less, but the number of individual trees is more, the number of individuals with large diameter is higher, especially there are many individuals of gymnosperm-conifer with large diameter 3.2.2.7 Closed evergreen sub-tropical rain forest mixed coniferous and broadleaf trees forest on soil mountains and limestone mountains: This type of forest begins at altitudes above 1,000 m but is mainly distributed at altitudes above 1200 m, occupying a small area compared to the whole conservation area, found mainly in Huong Son commune (Pa Thien waterfall area); the area is about 1,539 Canopy up to 60-70% Basically, the forest has a distinct 5-layers structure This type compare with the closed evergreen broadleaf forest, the number of timbertree species is less, the number of individuals with large diameter is more, mainly individuals belongs to the Gymnosperm phylum, mainly Dacrydium elatum (Roxb.) Wall ex Hook.) 3.3 Proposing solutions to conserve plant diversity in Bac Huong Hoa Nature Reserve 3.3.1 Causes of decline of plant diversity 3.3.1.1 Direct causes: The results of the investigation of the direct causes of the decline of plant diversity are arranged in the following order: illegal logging; illegal exploitation of non-timber forest products; clearing, burning fields for cultivation, burning fires; grazing freely; make patrol roads in the protected area, traffic roads, build hydroelectricity, power lines 3.4.1.2 Indirect causes: Analysis of the relationship between direct and indirect causes: Because the causes of "construction of hydroelectric power plants and power lines" and "building patrol roads in the NR" are the implementation of plans by local authorities, so consider only the following remaining reasons Table 3.28 Analysis of direct and indirect causes of plant diversity decreasing in Bac Huong Hoa Nature Reserve No Direct causes Indirect causes Illegal logging Poverty and underemployment The management and protection of forests is not strict Illegal exploitation of Poverty and underemployment non-timber forest The management and protection of products forests is not strict Lack of productive land Burning fields for Lack of productive land farming Poverty Free grazing Lack of land for livestock grazing Awareness of forest value is still low From the above Table, it can be seen that poverty and underemployment; lack of productive land; lack of land for grazing; awareness of the value of forests is still low; the management, inspection and patrolling of the forest is not tight, and the forest protection force is still small 3.4.2 The advantages in the conservation of plant diversity: The advantages in terms of natural and socio-economic conditions, mainly due to favorable soil and climate conditions; policy mechanism, Bac Huong Hoa Nature Reserve has been planned stably; Programs and projects are prioritized for implementation in the Nature Reserve 3.4.3 The difficulties in plant diversity conservation: The difficulties in natural and socio-economic conditions such as complicated terrain, poor infrastructure; policy mechanisms; programs and projects had have but are not continuous, low efficiency; forest management and protection 3.4.4 The measures to conserve plant diversity: (1) Economic development, hunger eradication, poverty alleviation, job creation for workers, improvement of policies; (2) Strengthening propaganda and education on awareness of forest protection; (3) infrastructure investment, planning review; (4) Scientific research, application of scientific and technical advances in cultivation, animal husbandry, development of appropriate programs and projects; (5) Strengthening capacity of staff in forest management and protection; (6) organizing monitoring activities CONCLUSIONS AND RECOMMENDATIONS CONCLUSIONS - Building plant species list: Flora of Bac Huong Hoa Nature Reserve has identified 1494 species, 703 genera in 168 families of phyla of vascular plants (Lycopodiophyta, Equisetophyta, Polypodiophyta, Pinophyta and Magnoliophyta) In which, additional species have been announced for the flora of Vietnam; recorded species with distribution in Vietnam, but before that, there was no document of Vietnam recorded them present in the territory of Vietnam Added to the list of Bac Huong Hoa Nature Reserve 13 families, 89 genera, 232 species In which, the Lycopodiophyta added genera and species; Ferns add families, 19 genera, 63 species; Angiosperms add families, 68 genera, 165 species - Evaluation of taxonomic diversity of flora: + Diversity at the phylum level: Among the 1494 species, Magnoliophyta absolutely dominates with 1316 species (99.09%), followed by the phylum Polypodiophyta, Lycopodiophyta and Equisetophyta The distribution of taxa in the phyla is un-equal + Diversity at family level: The richest family has 10 units with the number of species accounting for 30.32% of the total species of the whole plant, which are Orchidaceae, Rubiaceae, Euphorbiaceae, Asteraceae, + Diversity of genus level: The 10 richest genera account for 8.84% of the total species of the whole plant such as: Ficus, Ardisia, Lithocarpus, Asplenium, Pteris, + Diversity indexes: family index is 8.61; The genus index is 2.13 and the genus index on the family index is 4.18 - About the life form of plants: Ph = 6.21 Mg + 15.66 Me + 18.89 Mi + 24.77 Na + 6.38 Ep + 1.28 Suc + 12.00 Lp + 13.96 Hp + ,85 Pp SB = 79.02 Ph + 2.76 Ch + 9.08 Hm + 3.36 Cr + 5.78 Th - The geographical factors of plants: tropical factors in general have a very large proportion of 87.34%, followed by endemic factors with 13.25%, old tropical factors with 8.1%, the lowest in the system of tropical elements is the inter-tropical element 2.61%; temperate factors account for 9.37%, the lowest is the two global factors 0.67% and cultivation factors 1.27% - Use value of plants: there are 1058 plants species with use value (70.82% of species of the flora), of which the largest group of medicinal plants is 746 species (49.93%); followed by the group of edible plant with 303 species (20.28%) and the group of timbertree species with 236 species (15.28%), the remaining groups of plant all accounted for a lower proportion - About rare genetic resources: there are all 171 endangered, precious and rare plant species that need to be conserved in the Vietnam Red Book (2007), Decree No 06/2019/ND-CP of the Government government (2019) and IUCN list (2010), accounting for 11.44% of the total species of the system This is a relatively high percentage, so it should be given special priority in conservation - The forest vegetation types in Bac Huong Hoa Nature Reserve are classified into two groups: Group of vegetation types at altitudes under 800 m (with closed evergreen tropical rainforest with broadleaf trees; woodland forest broadleaf evergreen recovering from shifting cultivation or logging; woodland forest broadleaf forest mixed with wood and Bamboo; evergreen shrub; grassland less than m high, mainly plant of class Liliopsida) Group of vegetation types at altitudes above 800 m (with subtropical evergreen broadleaf evergreen closed forest; subtropical rainy season closed evergreen forest, mixed coniferous and broadleaf forest; woodland forest broad evergreen recovering from shifting cultivation or harvesting; woodland forest mixed broadleaf of wood and bamboo; evergreen shrub type; grassland type less than m high, mainly monocotyledonous plants) - Causes of decline in plant diversity in Bac Huong Hoa Nature Reserve, Quang Tri province include: There are direct causes: illegal logging; illegal exploitation of non-timber forest product; clearing and burning fields for cultivation; grazing freely; making patrol roads in the protected area; construction of hydroelectricity, power lines There are indirect causes: poverty and underemployment; lack of productive land; lack of land for grazing; people's awareness of the value of forests is still low; The management and inspection of forests is not strict, there are few forest protection forces - The solution to conserve plant diversity in Bac Huong Hoa Nature Reserve, Quang Tri province has groups: economic development, hunger eradication, poverty alleviation, job creation for workers; strengthen propaganda and education on awareness of forest protection; infrastructure investment, planning review; research and apply scientific and technical advances in cultivation and animal husbandry; strengthen capacity of staff in forest management and protection and conservation; organize monitoring activities RECOMMENDATIONS - It is necessary to continue to research and build a system of positioning plots to study and monitor the development rules of the forest ecosystem and the change of plant diversity in Bac Huong Hoa Nature Reserve - It is necessary to have methods to devise strategies for conservation of precious, rare, endangered plant species in Bac Huong Hoa Nature Reserve ... publishing house, Ha noi Do Thi Xuyen, Vu Xuan Phuong, Ha Van Hoan, Nguyen Anh Duc (2016), Genus Opithandra B L Burtt an Species Opithandra dinghushensis W T Wang as New records for the flora... mainly on strongly degraded lands due to erosion, long-term shifting cultivation and cattle grazing, scattered in the area of Bac Huong Hoa Nature Reserve, on small areas near the Station Forest... and Technology, Vol 32, No 1S (2016) 142-146 Ha Van Hoan, Nguyen Tan Hieu, Do Thi Xuyen, Nguyen Anh Duc (2017), State of threatened plants in Bac Huong Hoa Natural Reserve, Quang Tri province