Nghiên cứu sự phân bố và đa dạng thực vật bậc cao trên các vùng sinh thái khác nhau tại tỉnh an giang tt tiếng anh

MINISTRY OF EDUCATION AND TRAINING CAN THO UNIVERSITY -oOo- SUMMARY of THE PhD THESIS Major: Soil and water environment Code: 9440303 NGUYEN THI HAI LY THESIS TITLE STUDY ON HIGHER PLANT SPECIES DISTRIBUTION AND DIVERSITY ON THE DIFFERENT ECOLOGICAL AREAS IN AN GIANG PROVINCE Can Tho, 2019 This Study Was Achieved At Can Tho University Scientific Supervisor: Assoc Prof Dr Nguyen Huu Chiem This dissertation was defended at the University Examination Council At: …………………………………… At…hour , on date…month….year… Reviewer 1:…………………………… Reviewer 2:…………………………… The dissertation is available at: Learning Resource Center of Can Tho University National Library of Viet Nam LIST OF PUBLICATIONS [1] Nguyen Thi Hai Ly, Lu Ngoc Tram Anh, Tran Quoc Minh and Nguyen Huu Chiem, 2018 Vascular plant resources by soil types in mountainous area of An Giang province Journal of Science, Can Tho University (ISSN 1859-2333), 54:106-116 [2] Nguyen Thi Hai Ly and Nguyen Huu Chiem, 2017 Surveying vascular plant species component based on the types of soil in opened depression of flood plain in An Giang province Journal of Science, Can Tho University (ISSN 18592333), (2): 120-128 [3] Nguyen Thi Hai Ly, Lu Ngoc Tram Anh and Nguyen Huu Chiem, 2016 A survey of vascular plant species in the dry season, Cam Mountain, An Giang province Journal of Science and Technology, Vol 54, 2016 ISSN 0866-708X [4] Nguyen Thi Hai Ly, Le Van Quy and Nguyen Huu Chiem, 2016 Assessment of higher plant status in Cam mountain, An Giang province Journal of Environment (ISSN 1859-042X), 4:39-40 [5] Nguyen Thi Hai Ly, Lu Ngoc Tram Anh, Huynh Thi Tron and Nguyen Huu Chiem, 2017 Species composition of medicinal plants in Tinh Bien district, An Giang province Proceedings of the 7th National Scientific Conference on Ecology and Biological Resources, Hanoi (ISBN: 978-604913-615-3), 1332-1339 CHAPTER 1: INTRODUCTION 1.1 Introduction Terrestrial plants usually absorb nutrients from the different soil, water and air environments (Chapin et al., 2002), so when the changing environment can change plant composition (Tavili and Jafari, 2009) The groups of factors which affected their distribution and diversity were the geographical group (topography, slope), the group of direct physiological impact on plant growth but are not consumed (pH) and nutritional groups effect to their growth (Austin et al., 1984) In the same ecological conditions, the soil was a filter to prevent the presence of plant species that lacked essential physiological characteristics for surviving (Pausas and Austin, 2001) The physicochemical properties of soil have influenced the distribution and diversity of flora (Zuo et al., 2009; Ritu et al., 2010; Shabani et al., 2011) The texture, pH, and nutrients were factors that closely affected the change of vegetation in areas (Fayolle et al., 2012; Dado and Jiwen, 2014) Therefore, the distribution and diversity of plants follow the soil condition need to be studied An Giang province has a variety of topography and many different ecosystems Besides the agricultural ecosystem, there also has the forest ecosystem on the mountains and the forest ecosystem of plain (Nguyen Duc Thang, 2003) Many rare and precious native species adapted to the specific ecological condition of the province (Vo Van Chi, 1991; Nguyen Duc Thang, 2003; Nguyen Van Minh et al., 2008; Nguyen Van Kien, 2013) Nowadays, the loss of forests and overexploitation has led to the disappearance of many rare and precious species Facing the risk of biodiversity loss, in 2008, the Biodiversity Law was born and became the principle for developing biodiversity conservation planning In the same climatic conditions, the differences in geography, soil and depth of flooding were the basis of science to determine three different ecological areas in An Giang as fluvial plain, mountainous area, opened depression of floodplain (Nguyen Huu Chiem, 1993; Nguyen Hieu Trung et al., 2012) Although plant diversity has been studied in An Giang province (Vo Van Chi, 1991; Nguyen Duc Thang, 2003), the results only focused on taxon diversity These studies have not mentioned the distribution and diversity of plant according to soil condition and factors affecting this status in various ecological areas Therefore, it is necessary to determine the distribution and diversity of plants and factors that impact on this status according to the soil in different ecological areas in An Giang province Because of these issues, the thesis "Study on the distribution and diversity of higher plants on different ecological areas in An Giang province" has been implemented 1.1 Objectives of study 1.1.1 General objective Determination of the distributional and diverse status of higher plants in different ecological areas will be considered the scientific basis for the conservation and sustainable exploitation of plant resources in An Giang province 1.1.2 Specific objectives + Determination of the physicochemical characteristics of soil in ecological areas of An Giang province according to the soil depth + Determination of the distribution and diversity status of vascular plants and factors that affected this status follow the soil condition in three ecological areas of An Giang province 1.3 The contents of the study + Surveying and assessing soil characteristics in ecological areas + Investigating and assessing the plant diversity status according to the soil environment in these ecological regions + Analysing the relationship between soil and plant diversity + Building the distributional map of dominant and rare plant species which representing each ecological areas +Proposing the solutions for conservation and sustainable exploitation of plant resources in An Giang province 1.4 New findings of the thesis + The results have been added 56 species, belonging to 30 families to the flora of An Giang province + The thesis identified the number of wild species and anthropospecies and the distribution of rare, endemic, local and dominant species according to soil properties for three ecological regions in An Giang province + The results added some chemical and physical characteristics of each soil type in three ecological regions and some data on soil characteristics according to elevation belts in mountainous areas + The study assessed the status of diversity through the various diversity indices according to the characteristics of soil in each ecological region From there, the results indicated that soil and human factors influenced the diversity and dominant plant + Three distribution maps of dominant and rare species have been built to support the management of plant resources and biodiversity conservation in An Giang province 1.5 Objects and scope of the research 1.5.1 Objects of the research Vascular plant species and physico-chemical parameters of soil 1.5.2 The scope of the research + Three different ecological areas in An Giang are fluvial plain (Cho Moi, Phu Tan, Tan Chau, Chau Phu, Chau Thanh, Thoai Son), mountainous area (Bay Nui area in Tri Ton and Tinh Bien district), opened depression of floodplain (the plain of Tri Ton and Tinh Bien district) + Research at quadrats on the surveyed transects in these ecological regions with woody (D1,3≥6 cm) and herbaceous plants + The samples were collected from June to December (except for dry season) in mountainous areas and from December to June (except for flooding season) in fluvial plain and opened depression of floodplain 1.6 The scientific and practical significance of the study + Scientific significance: The thesis provides a scientific basis for the current distribution and diversity of vascular plants according to the soil environment of three typical ecological regions in An Giang province + Practical significance: The informations of thesis that can be used in forestry, environment and local management agencies CHAPTER 2: LITERATURE REVIEWS 2.1 The concept of vascular plant The vascular plants are characterized by specialized vascular tissue and have reproductive organs with spores, cones or flowers (Nguyen Nghia Thin, 2008) The two types of vascular tissue, xylem and phloem, are responsible for moving water, minerals, and the products of photosynthesis throughout the plant (Hoang Thi San and Nguyen Phuong Nga, 2003) They include Rhyniophyta, Psilotophyta, Lycopodiophyta, Equisetophyta, Polypodiophyta, Pinophyta and Angiospermatophyta 2.2 Overview of ecological areas in An Giang province Based on the topographical features, the depth of inundation in the flood season and soil conditions, An Giang province was located in three main ecological areas as mountainous area, fluvial plain, and opened depression of floodplain (Nguyen Huu Chiem, 1993; Nguyen Hieu Trung et al., 2012) a b ) Figure 2.1: (a) The agro-ecological zones map in Mekong Delta (Nguyen Hieu Trung et al., 2012) and (b) The agro-ecological zones map in An Giang province +Climate condition: The three ecological areas were the same features of temperature, humidity and the average of rainy days However, the average annual rainfall in the fluvial plain (1200–1700 mm) was higher than two remaining ecological regions (1200-1600 mm) (Luu Van Ninh et al., 2018) + Characteristics of topography and soil The mountainous area has a slope of 150-350, including many mountains with the highest peak of 710 m in Cam Mountain Also, the field around the foot of mountains has an elevator of 5-10 m and not inundation in the flood season (Nguyen Duc Thang, 2003) The mountainous soil has three main types as Ferralsols, Leptosols, and Acrisols (Southern Sub-National Institute of Agricultural Planning and Projection, 2003) The opened depression of floodplain is a low-lying field in Long Xuyen Quadrangle surrounding two districts of Tri Ton - Tinh Bien Due to the low topography and upstream position, it is flooded annually for 3-4 months with a depth of inundation over 0.5 m and heavy acid sulfate soils (Nguyen Duc Thang, 2003) The soil in this area consists of three types of soils as acid sulfidicpeat soil, active acid sulfate soil with sulfuric materials present near layer (0-50 cm), and depth in soil (>50 cm) The fluvial plain along Tien and Hau rivers has geomorphological units such as natural levees, sandbars and backswamps (Nguyen Huu Chiem, 1993), and a depth of inundation over 0.5 m (Nguyen Hieu Trung et al., 2012) Alluvial soil types are classified into four categories such as Anofluvic and Orthofluvic fluvisols, Gleyic and Cambic fluvisols CHAPTER 3: METHODOLOGY 3.1 Methods of plant diversity investigation and assessment 3.1.1 Plant survey method a) The flora survey in the mountainous area: 230 quadrats (100m2) were done from June 2015 to May 2017 in the soil of Ferralsols, Leptosols and Acrisols The quadrats were located at each altitude level of 100 m, with square100 m2 for woody plants (D1.3≥ 6cm) and shrubs Each quadrate (100m2) was designed sub-quadrates (1m2) for the herbaceous plants diagonally The fields were also established quadrates (1m2) (Le Quoc Huy, 2005; Hoang Chung, 2006) b) The flora survey in the opened depression of floodplain: From July 2016 to April 2017, 85 quadrats (100m2) were surveyed in acid sulfidicpeat soil, active acid sulfate soil with Jarosite at depth 0-50 cm and Jarosite at depth over 50 cm in the plains of Tri Ton and Tinh Bien districts Each quadrate (100m2) was designed sub-quadrates (1m2) for the herbaceous plants diagonally The fields were also established quadrates (1m2) c) The flora survey in the fluvial plain: From January 2017 to December 2017, 155 quadrats (100m2) were surveyed in a part of the floodplain along the Hau River and Tien River including Cho Moi, Phu Tan, Tan Chau, Chau Thanh and Chau Phu districts The quadrats were located in four types of alluvial soils as Anofluvic and Orthofluvic fluvisols, Gleyic and Cambic fluvisols Figure 3.1: The position of quadrats in three ecological areas (IRMC, 2003) Using GPS to determine coordinates of quadrats In the quadrats, data were collected including (i) the number of species; (ii) the number of individuals (the number of root for shrubs and herbs, the number of stems for climbing herbs) (Le Quoc Huy, 2005) The local people were interviewed for local names and uses, frequency of changes in crop, cutting down and planting, herbicide spraying, take out weeding, fertilizer application and tillage The number of households were surveyed in the mountainous areas as n=60 (woods) and n=75 (herbs); in the opened depression of floodplain as n=32 (woods) and n=41 (herbs), in the fluvial plain as n=92 (woods) and n=108 (herbs) 3.1.2 Identifying the scientific name of species and list of plant The morphological comparison method was applied to determine the species’s name based on Cay co Viet Nam – Vol 1,2,3 (Pham Hoang Ho, 1999), Tu dien thuc vat thong dung – Vol 1,2 (Vo Van Chi, 2002) The uses of plants were investigated in the local communities and searched from some documents such as Nhung cay thuoc va vi thuoc Viet Nam (Do Tat Loi, 2004), Tu dien cay thuoc Viet Nam (Vo Van Chi, 2018) and Tinh dau (Le Ngoc Thach, 2003) The list of plants was done with information of taxon, stems characteristic, utility and the types of distribution soil 3.1.3 Method of diversity assessment + Determinating of rare and precious species based on the Vietnam Red Book - Part II (Plant), Decree No 32/2006/ND-CP and rare index (RI) 𝐧 𝐑𝐈 = (𝟏 − ) × 𝟏𝟎𝟎 𝐍 RI is a rare index; n is the number of quadrats that appeared the survey species; N is the total quadrats in the surveyed area + Diversity assessment by alpha diversity indexes (Table 3.1): Table 3.1: The alpha diversity indexes (Clarke and Gorley, 2006) Index Formulas Meaning S: total A measure of the Margalef species abundance of species d=(S-1)/logeN (d) N: total present for a given individual number of individuals H’: A measure of degree of Pielou’s J’=H’/logeS Shannon evenness in species (J’) index abundances A measure of species Shannon H’=-∑ 𝑃𝑖 ∗ Pi: Ni/N diversity in a (H’) log⁡(𝑃𝑖) community Ni: total A measure of species Simpson λ’={∑ 𝑁𝑖(𝑁𝑖 − individual dominance in a (λ’) 1)}/{𝑁(𝑁 − 1)} of species i community + Assessing the similarity of flora through Sorensen index: 𝐒 = 𝟐𝐜/(𝐚 + 𝐛) S: Sorensen index (from to 1); a: number of The results of the correlation analysis show that the local human impact was significant on herbaceous plants in Leptosols and Acrisols soil This impact increased the value of (d) index but reduced the value of H' and J' with 0.32