Characteristics of mangrove forest communities in xuan thuy national park – nam dinh

MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT VIETNAM FORESTRY UNIVERSITY STUDENT THESIS Title CHARACTERISTICS OF MANGROVE FOREST COMMUNITIES IN XUAN THUY NATIONAL PARK – NAM DINH Major: Natural Resources Management Code: D850101 Faculty: Forest Resources and Environmental Management Student: Vu DucHuy Student ID: 1253090017 Class: K57 Natural Resources Management Course: 2012 - 2016 Advanced Education Program Developed in collaboration with Colorado State University, USA Supervisor: Dr.HaQuang Anh Ha Noi, 10/2016 ACKNOWLEDGEMENTS During the process of learning and finishing this thesis, I have received guidance, valuable help of the teachers and friends Without their assistances, advice, collaborations and supports, this thesis would not have been possible First and foremost, I would like to thank all teachers in Advanced Program for the valuable knowledge and your enthusiasm to build strong background, especially my supervisor - Dr Anh Quang Ha I am grateful to him for valuable guidance, supporting and comments throughout the various stages of this thesis, what help me carry out this thesis Many thanks are due to my friends in K57 – Advanced Curriculum You help me a lot when I collect and analyze data Thanks for study time we have been together at Vietnam National Forestry University I always appreciate our friendship Lastly, I express my gratitude to management board of Xuan Thuy National Park Thanks Mr Nguyen Viet Cach – Head of XTNP and Mr Pham Xuan Hoi for your help when I was in XTNP, and Mr Ngo Xuan Chieu for your directly guidance to help me collect valuable data Hanoi, October 2016 Vu Duc Huy ABSTRACT Mangrove ecosystems play significant role for protecting coastal areas However, the area and quality of mangrove are affected not only by weather patterns, but by human activities also Understanding the structure of mangrove community and regeneration are very important to manage mangrove ecosystem effectively Field investigation and statistic are main method that use in this research Mangrove community in Xuan Thuy National Park (XTNP) include three main woody species Kandelia candel, Sonneratia caseolaris, and Aegiceras corniculata that make up five types of forests Mangrove forests in XTNP grow and develop well, high density, and in high quality However, regeneration trees are in low quality They distribute unequally, randomly and in low density Regeneration trees are mainly damaged by weather condition (storm, sea-level rising) and human activities (collecting NTFPs, waste water from aquaculture area) In order to enhance quality of mangrove forests and regeneration in XTNP, some silviculture technique should be applied such as: plant new species that adapt to the environment conditions in study area (Sonneratia apetala), selective thinning to reduce competition between individual trees, control waste water from aquaculture area before release to the environment, raise awareness for people to protect mangrove forests and limit activities which damage to the forests, especially in core zone Key word: mangrove; regeneration; structure TABLE OF CONTENT ACKNOWLEDGEMENTS ABSTRACT TABLE OF CONTENT LIST OF TABLE LIST OF FIGURE ABBREVIATION INTRODUCTION: GOALS AND (SPECIFIC) OBJECTIVES: 12 2.1 Overall goal: 12 2.2 Specific objectives: 12 METHODS: 12 3.1 Secondary data 12 3.2 Sample plot establishment 13 3.3 Data collection 14 3.4 Data analysis 16 OVERVIEW OF STUDY SITE 18 4.1 Natural characteristic 18 4.1.1 Geographical location 18 4.1.2 Topography and hydrology 19 4.1.3 Climate 20 4.1.4 Soil condition 20 4.1.5 Biodiversity 21 4.2 Population 22 4.3 Economic condition 22 RESULTS 23 5.1 Structure of mangrove forests 23 5.2 Structure of regeneration 45 DISCUSSION 55 CONCLUSION 58 REFERENCES: APPENDIX: LIST OF TABLE Table 5.1: Table of statistic of forest status 23 Table 5.2: Table of height distribution frequency in plot of forest status 24 Table 5.3: Table of height distribution frequency in plot of forest status 24 Table 5.4: Table of height distribution frequency in plot of forest status 25 Table 5.5: Table of statistic of forest status 27 Table 5.6: Table of height distribution frequency in plot of forest status 28 Table 5.7: Table of height distribution frequency in plot of forest status 28 Table 5.8: Table of height distribution frequency in plot of forest status 29 Table 5.9: Table of statistic of forest status 31 Table 5.10: Table of height distribution frequency in plot of forest status 32 Table 5.11: Table of height distribution frequency in plot of forest status 32 Table 5.12: Table of height distribution frequency in plot of forest status 33 Table 5.13: Table of statistic of forest status 35 Table 5.14: Table of species composition in forest status 36 Table 5.15: Table of height distribution frequency in plot of forest status 37 Table 5.16: Table of height distribution frequency in plot of forest status 37 Table 5.17: Table of height distribution frequency in plot of forest status 38 Table 5.18: Table of statistic of forest status 39 Table 5.19: Table of species composition in forest status 40 Table 5.20: Table of height distribution frequency in plot of forest status 41 Table 5.21: Table of height distribution frequency in plot of forest status 41 Table 5.22: Table of height distribution frequency in plot of forest status 42 Table 5.23: Table of regeneration investigation in forest status 45 Table 5.24: Table of regeneration investigation in forest status 47 Table 5.25: Table of regeneration investigation in forest status 49 Table 5.26: Table of regeneration investigation in forest status 51 Table 5.27: Table of regeneration investigation in forest status 53 LIST OF FIGURE Figure 1: Measurement equipment 14 Figure 1: Xuan Thuy National Park (Source: Xuan Thuy National Park, 2015) 18 Figure 5.1: H-D correlation in forest status 26 Figure 5.2: H-D correlation in forest status 30 Figure 5.3: H-D correlation in forest status 34 Figure 5.4: H-D correlation of Kandelia candel in forest status 43 Figure 5.5: Quality of regeneration in forest status 46 Figure 5.6: Quality of regeneration in forest status 48 Figure 5.7: Quality of regeneration in forest status 50 Figure 5.8: Quality of regeneration in forest status 52 Figure 5.9: Quality of regeneration in forest status 54 ABBREVIATION XTNP: Xuan Thuy National Park NTFPs: Non-timber forest products UNESCO: the United Nations Educational, Scientific and Cultural Organization DBH: Diameter at Breast Height Dcanopy: Diameter of canopy INTRODUCTION: Mangroves are found in 123 countries and territories globally; with total area is 152,000 square kilometers (Spalding et al., 2010) The term “mangrove” considers both ecosystem and the plant families that have adaptability to grow in tidal environment (Tomlinson, 1986) Mangrove tree grow between latitudes 25oN and 30oS (Valiela et al., 2001) They form forests of salt-tolerant species, with complex food webs and ecosystem dynamics (Macnae, 1968; Lugo and Snedaker, 1974; Tomlinson, 1986) The first attempt to estimate total mangroves area over the world was undertaken as part of “Tropical Forest Resources Assessment” (FAO and UNEP, 1980) The total mangrove area was estimated approximately 15.6 million hectares in this study Dynamic of mangroves area over years was estimated continuously over year through many report such as Saenger et al.,(1983), FAO (1994), Groombridge (1992), ITTO & ISME (1993), Fisher & Spalding (1993), Spalding et al.,(1997), Alzupuru et al.,(2000) In Vietnam, mangrove vegetation is divided into zones: North-east coast from Ngoc cape to Do Son cape (zone I), Northern delta from Do Son cape to Lach Truong River (zone II), central coast from Lach Truong to Vung Tau cape (zone III) and Southern delta from Vung Tau cape to Ha Tien (zone IV) Only number of plant species has physiological and structural characteristics in order to adapt to the brackish water habitat, for example: Rhizophoraceae, Avicenniaceae and Combretaceae - the number of species is ranges from 50 to 70 according to different classification (Tomlinson, 1986; Saenger, Hegerl and David, 1983; Lugo and Snedaker, 1975; Aksornkoae et al., 1992) Processing exceed salt in the absorbed water is one of the biggest challenges in the salty environment Mangrove tree species have several methods to desalinate ocean water, according to species (FAO, 2007) They may exclude the uptake of salt at the root level, or remove excess salt at the leaf level by using salt excretion glands, by cuticular transpiration at the leaf level transpiration at leave level, or by accumulating the salt in leaf tissues and then shedding the leave (FAO, 2007) Mangrove ecosystems provide not only ecological functions, but economic functions also There are number of ecological functions which are provided by mangrove ecosystems such as: - Reduction of environment pollution It helps to consume a significant amount of harmful emission and increase the amount of oxygen release to the environment Thus, it can contribute to reduce the global warming and prevent rising of water affect the lives of coastal resident - They play significant role as filters in the processing of waste In addition, it also works to handle nutrients from land and served as buffers against pollution runoff and filter food for marine animals - Help protect animals when high tide and big waves, making the diversity of mangrove ecosystems are relatively stable - Through the dense root system of mangrove, they can protect estuarine coastal from erosion and prevent and reduce consequences of storms and waves on the sea dyke system - A good place to organize eco-tourism, training, research and teaching Moreover, mangroves ecosystems play an important role in providing economic benefit at local and national level Local people depend on mangrove as the source of wood (timber, poles, fuel-wood and charcoal) and NTFPs (food, thatch, alcohol, medicine and honey) Mangroves also provide tannin, suitable source for leather work and for curing and dyeing of fishing nests However, this product has declined in recent years, mainly because of the introduction of nylon fishing nets and the use of chrome as the predominant agent for curing leather (FAO, 1994) The first research on mangrove ecosystem in Vietnam is doctoral thesis of Humbert-Vu Van Cuong (1964) He described in detail saltwater communities and brackish communities in Sai Gon River and Vung Tau with soil factors The second research is a book named “Mangrove forest in Vietnam” of Nguyen Van Than and Lam Binh Hoi (1972) In this book, they identified and analyzed based on silviculture technique Thesis of Phan Nguyen Hong (1970) on “Ecological characteristic of flora, vegetation floor in coastal area of Northern Vietnam” and his number of reports also mentioned quite enough characteristics if mangrove forests in northern Vietnam In Vietnam, there is a special committee research on mangroves that names MERD (Mangrove Ecosystems Research Division) belong to CRES (Centre for Natural Resources and Environment Studies) Besides, there are other Center of Natural Resources and Environment of Forest Inventory and Planning Institute, Institute of Forestry, Vietnam National University of Forestry to participate in research on mangroves ecosystems Xuan Thuy National Park locates in Giao Thuy district, Nam Dinh Province The area was declared the country’s first Ramsar site by the Bureau of the Convention on Wetlands of International Importance in January 1989 Since then, the Government of Vietnam has worked very hard to preserve the value of this area through the establishment of new laws, policies and investments In 2003, it was upgraded from its status as a nature reserve and approved as a national park by the Prime Minister, and was also included as part of the Red River Delta World Biosphere Heritage Site by UNESCO in October 2004 The total area is approximately 7,100 hectares of core zone, and 8,000 hectares of buffer zone While core zone is a strictly protected area without any human activities allowed, the buffer zone acts as transition area where activities are regulated to restrict and reduce adverse human impacts on the park Endowed with rich alluviums, the park boasts a Table 5.26: Table of regeneration investigation in forest status Plot Species Kandelia Quality Number Density composition composition (trees/ha) coefficient formula %X Good 0.00 Medium 22.22 1000 3.9 candel Bad 77.78 3500 Total 100.00 4500 6.1A+3.9K Aegiceras Good 0.00 Medium 35.71 2500 6.1 corniculata Kandelia Bad 64.29 4500 Total 14 100.00 7000 Good 13.64 1500 Medium 40.91 4500 5.9 candel Bad 10 45.45 5000 Total 22 100.00 11000 5.9K+4.1A Aegiceras Good 26.67 2000 Medium 13.33 1000 4.1 corniculata Bad 60.00 4500 Total 15 100.00 7500 51 Kandelia candel Good 30.77 4000 Medium 23.08 3000 5.8 Bad 12 46.15 6000 Total 26 100.00 13000 Good 0.00 Medium 31.58 3000 5.8K+4.2A Aegiceras corniculata 4.2 Bad 13 68.42 6500 Total 19 100.00 9500 Three plots have three different composition formula respectively 6.1A+3.9K, 5.9K+4.1A, and 5.8K+4.2A Regeneration has high density 14.29 Good Medium 57.14 28.57 Bad Figure 5.8: Quality of regeneration in forest status Quality of regeneration is bad Rate of regeneration in bad quality is four times as much as the rate in good quality (57.14% in comparison with 14.29%) e) Investigation in forest status 52 Result of investigation in forest status is shown in the table below Table 5.27: Table of regeneration investigation in forest status Plot Species Number %X Density composition compositio (trees/ha) coefficient n formula Good 28.57 333 Kandelia Medium 0.00 candel Bad 71.43 833 Total 100.00 1167 Good 0.00 Medium 66.67 333 Sonneratia Quality caseolaris 3.3 5.2A+3.3K 1.4 Bad 33.33 167 Total 100.00 500 Good 0.00 Aegiceras Medium 27.27 500 corniculata Bad 72.73 1333 Total 11 100.00 1833 Good 0.00 Kandelia Medium 53.85 1167 candel Bad 46.15 1000 Total 13 100.00 2167 Good 13.33 333 Sonneratia Medium 40.00 1000 caseolaris Bad 46.67 1167 Total 15 100.00 2500 Good 42.86 1500 Aegiceras Medium 4.76 167 corniculata Bad 11 52.38 1833 Total 21 100.00 3500 Kandelia Good 29.41 833 candel Medium 23.53 667 53 +1.4S 5.2 2.6 3.1 4.3A+3.1S +2.6K 4.3 3.0 4.3A+3.0K +2.7S Bad 47.06 1333 Total 17 100.00 2833 Good 33.33 833 Sonneratia Medium 26.67 667 caseolaris Bad 40.00 1000 Total 15 100.00 2500 Good 12.50 500 Aegiceras Medium 11 45.83 1833 corniculata Bad 10 41.67 1667 Total 24 100.00 4000 2.7 4.3 Regeneration has high density Three plots have three different composition formula respectively 5.2A+3.3K+1.4S, 4.3A+3.1S+2.6K, and 4.3A+3.0K+2.7S 20.63 Good 49.21 Medium Bad 30.16 Figure 5.9: Quality of regeneration in forest status Quality of regeneration is bad Rate of regeneration in bad quality is over twice as much as the rate in good quality (49.21% in comparison with 20.63%) 54 In five forest status, regeneration has high density However, trees distribute unequally between plots Furthermore, percentage of bad quality regeneration is significant Trees are mainly topless or be cracked DISCUSSION Mangrove forests have high density Quality of mature trees are mainly good, straight stem, developed canopy, less disease or pests Sonneratia caseolarishas the larger size than Kandelia candel and Aegiceras corniculata In case of N/D, most of the trees has the relatively similar high (about 2.5m to 4.0m), except for the case of Sonneratia caseolaris Canopy develop well,canopy cover in each plot reaches high value Composition formula of mature tree and regeneration are relatively similar:6.8A+3.2K, 5.8A+4.2K, and 6.2A+3.8K (mature mixed forest of Kandelia candel and Aegiceras corniculata)and 5.2A+3.8K+1.0S, 4.8K+4.4A+0.8S, and 5.4A+2.9K+1.7S (mature mixed forest of all three species) in comparison with 6.1A+3.9K, 5.9K+4.1A, and 5.8K+4.2A(regeneration mixed forest of Kandelia candel and Aegiceras corniculata), and 5.2A+3.3K+1.4S, 4.3A+3.1S+2.6K, and 4.3A+3.0K+2.7S(regeneration mixed forest of all three species) In case of Sonneratia caseolariscomposition structure, rate of mature trees is less in comparison with the rate of regeneration of this species in the formula Furthermore, quality of regeneration is relatively bad Rate of tree in bad quality in most of plots are higher than 50% Trees are mainly topless or be cracked by outer force (storm, wave, or human activities) Therefore, a part of regeneration cannot grow up to the mature trees There are number of reason that affect to the forests and regeneration quality in study area: 55 - Salinity: this area has high salinity (20‰ to 27‰ in winter, and 28‰ to 30‰ in summer) It can reduce growth ability of some species, such as Sonneratia caseolaris; - Extreme weather such as storm, or sea-level rising can damage mangrove forests, especially regeneration trees; - Chemical that leak from shrimp farm can modify habitat condition for mangrove forests (pH, salinity, DO, BOD,…) It can bring bad effects to mangrove ecosystems; - Because of high density, competition between different species and individual in the same species increase; - Damage from human activities While collecting NTFPs, people can step on regeneration trees and break them down From the cause that affect to forests and regeneration quality, this thesis propose several silviculture technique in order to manage and protect mangrove forests in study area: - Plant new species, which can adapt to the salinity in this area, for example Sonneratiaapetala; - Selective thinning: thinning trees has disease, topless, bad quality to reduce competition and create room for new regeneration; - Control water quality from shrimp farm Develop waste water treatment before release to the environment; - Raise awareness for people to protect mangrove forests Limit activities which damage to the forests, especially in core zone Research on structure of mangrove forests and regeneration has practical significance It will be basic for other further study, such as research on carbon 56 sequestration in mangrove forests, research on biodiversity in mangrove forests, or ability to prevent tidal or wind In progress of carrying out this study, there are several limit that can affect to the quality also result of study: - Lack some information such as age of forest, plantation documents; - Simple equipment can affect to the errors of measurement; - Weather condition: the time study is carried out has number of storm, and rainy; - Limit of time and budget 57 CONCLUSION Mangrove forests have significant role for livelihood in coastal area Understanding structural characteristic of mangrove forests can help management having accordant policies and plans in order to protect and improve this valuable resource In study area, woody species make up types of forests, include: pure forest of Kandelia candel, pure forest of Sonneratia caseolaris, pure forest of Aegiceras corniculata, mixed forest of Kandelia candel and Aegiceras corniculata, and mixed forest of all three species Forests develop well, in good quality, stem straight and large, high density For the mix forest, several composition structure has been identified: 6.8A+3.2K, 5.8A+4.2K, and 6.2A+3.8K (mixed forest of Kandelia candel and Aegiceras corniculata), and 5.2A+3.8K+1.0S, 4.8K+4.4A+0.8S, and 5.4A+2.9K+1.7S (mixed forest of all three species) Regeneration trees have high density However, quality is relatively bad, and distribute unequally Some composition structure of regeneration include: 6.1A+3.9K, 5.9K+4.1A, and 5.8K+4.2A(mixed forest of Kandelia candel and Aegiceras corniculata), and 5.2A+3.3K+1.4S, 4.3A+3.1S+2.6K, and 4.3A+3.0K+2.7S(mixed forest of all three species) Trees are mainly topless or cracked by outer forces Bases on the cause that affect to the quality of forests, also regeneration in study area, research propose some solution in order to enhance management and protect mangrove forests, for example: plant adaptive species, thinning, develop waste water treatment In addition is raise awareness of local people to protect mangrove forests and biodiversity 58 REFERENCES: FAO (2007): The World’s mangroves 1980 – 2005 Nguyen Van Than and Lam Binh Hoi (1972): Mangrove forest in Vietnam Phan Nguyen Hong (1970): Ecological chracteristic of flora, vegetation floor in coastal area of Northern Vietnam Ivan Veliela, Jennifer L Bowen, and Joanna K.York (2001): Mangrove forests: one of the World’s threatened major tropical environments Lugo AE and Snedaker SC (1974): The ecology of mangroves Annual review of ecology and systematics 5: 39-64 Saenger P, Hergel EJ, Davie JDS (1983): Global status of mangrove ecosystems The environmentalist (supplement 3) Spalding MD, Blasco F, Field CD (1997): World Mangrove Atlas, Okinawa (Japan): International society for mangrove ecosystems Tomlinson PB (1986): The botany of mangroves Cambridge (UK): Cambridge University Press Macnae W (1986): A general account of fauna and flora of mangrove swamps in the Indo-West Pacific region Advances in Marine biology 6: 73-270 10 Aizpuru M., Achard F., and Blasco F (2000): Global assessment of cover change of the mangrove forests using satellite imagery at medium to high resolution EEC Research Project No 15017-1999-05 FIELD ISP FR Ispra, Italy, Joint Research Centre 11 Aksornkoae S., Maxwell G.S., Havamound S., and Panichsuko S (1992): Plants in mangroves Bangkok, IUCN Asian Regional Office 12 FAO (1994): Mangrove forest management guidelines FAO Forestry Paper 117 Rome 13 Fisher P and Spalding M.D (1993): Protected areas with mangrove habitat Cambridge, UK, UNEP-World Conservation Monitoring Centre 14 Groombridge B (1992): Global biodiversity: Status of the earth’s living resources UNEP-WCMC/The National History Museum/IUCN/Worldwide Fund for Nature/World Resources Institute London, Chapman and Hall 15 Lugo A.E and Snedaker S.C (1975): Properties of a mangrove forest in southern Florida, pp 170-212 In: G.E Walsh, S.C Snedaker and M.J Teas, eds Proceedings of the International Symposium on Biology and management of mangroves Gainesville, Florida, USA, University of Florida APPENDIX: Appendix 1: Investigate structural characteristic of mangrove forest Location: Date of survey: ID Species Investigator: Height DBH Dcanopy Note Appendix 2: Investigate regeneration Location: Date of survey: Plot Species Investigator: Height Quality Note