Coastal mangrove change detection using multi temporal landsat data in xuan thuy national park nam dinh province during 2000 2015

To contribute develop sustainable management of coastal mangroves the study of “Coastal mangrove change detection using mutil-temporal landsat data in Xuan Thuy National Park, Nam Dinh

MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT

MULTI-Major: Natural resource management

Code: D850101

Faculty: Forest resource and environmental management

Student: Nguyen Pham Minh Huyen Student ID: 1153091140 Class: K56 Natural resource management Course: 2011-2015

Advanced Education Program

Developed in collaboration with Colorado State University, USA

Supervisor: Dr Nguyen Hai Hoa

Ha Noi, 2015

During the process of learning and finishing this thesis, I have received guidance, valuable help of the teachers, brothers and friends With respect and gratitude, I like to express my sincere thanks to:

The administration of Vietnam Forestry University, Faculty of Forest Resources and Environmental Management, Department of Environmental and the lectures you have the knowledge and enthusiasm to impart valuable knowledge for us

During learning in the Vietnam Forestry University, Dr Nguyen Hai Hoa has dedicated guide us through each classroom session and created favorable conditions for the learning process to complete this thesis He is enthusiastic guide throughout the process of implementing post graduate thesis from beginning until completion

Finally, I wish that lectures in Department of Environmental Engineering really good health and confidence to continue performing noble mission on the transfer of knowledge for future generations

Hanoi, 31 August 2015

Nguyen Pham Minh Huyen

The Vietnam mangroves have been larger and rich and they play an important role for forest ecosystems, biodiversity and local livelihoods and development However, the management of mangroves in Vietnam is still facing many challenges The process of transition to market economy under reform policy has brought high economic growth of 7

to 8% in the first 5 years of the twenty-first century with the changes in livelihood patterns Vietnam faces big challenges of environmental problems as a result of overfishing, mismanagement of natural resources and the pressures of globalization The changes in the social, ecological, economic and institutional schemes gave the livelihood systems of mangroves increasingly complex and vulnerable To contribute develop sustainable

management of coastal mangroves the study of “Coastal mangrove change detection

using mutil-temporal landsat data in Xuan Thuy National Park, Nam Dinh province during 2000-2015” was conducted The study is based on using NDVI value to indentify

the change mangroves, forest plantation, water and rice paddy and aquaculture cross the time series The finding will contribute significantly to enhance sustainable management of mangroves by presenting possible solutions for study area

Keywords Remote sensing technology; GIS; Vegetation cover; Index vegetable

ACRONYMS

GPS Global Positioning System

GIS Geographic Information System

NDVI Normalized Difference Vegetation Index XTNP Xuan Thuy National Park

TABLE OF CONTENTS

PREFACE - 1

ABSTRACT - 2

ACRONYMS - 3

TABLE OF CONTENTS - 4

LIST OF TABLES - 7

LIST OF FIGURES - 8

CHAPTER I.INTRODUCTION - 9

2.1 GEOGRAPHIC INFORMATION SYSTEM (GIS) - 14

2.1.1 Definitions - 14

2.1.2 Origins and evolution of GIS - 14

2.1.3 Composition of GIS - 14

2.1.4 Functions of GIS - 15

2.2 REMOTE SENSING TECHNOLOGY (RS) - 15

2.2.1 Definitions - 15

2.2.2 The basic principle of Remote Sensing - 16

2.2.3 Applications of Remote Sensing - 17

2.3 COASTAL MANGROVES - 17

2.3.1 Definition of mangroves - 17

2.3.2 Mangrove forest characteristic - 18

2.3.3 The role of mangroves - 18

2.3.3.1 Ecological functions - 18

2.3.3.2 Economic functions - 19

2.4 APPLICATIONS OF GIS AND REMOTESENSING TO MANGROVE MAPPING19 CHAPTER III STUDY GOAL, OBJECTIVES AND METHODOLOGY - 21

3.1 STUDY GOAL, OBJECTIVES - 21

3.1.1 Research questions - 21

3.1.2 Research objectives - 21

Study goal: - 21

Specific objectives: - 21

3.2 SCOPE OF THE STUDY - 22

3.3 CONTENTS AND METHODOLOGY - 22

3.3.1 Investigate the status of mangrove cover and its management schemes in Xuan Thuy National Park - 22

Remote sensing data for study: - 23

Status of coastal mangrove management and mangrove structures - 23

3.3.2 Quantifying coastal mangrove changes in Xuan Thuy National Park during 2000- 2015 29

3.3.3 Identifying key drivers of coastal mangrove cover changes in Xuan Thuy National Park: - 30

CHAPTER IV STUDY SITE, NATURAL AND SOCIAL FEATURE - 32

4.1 STUDY AREA - 32

4.1.1 Natural characteristics - 32

4.1.1.1 Geographical location - 32

4.1.1.2 Topography and hydrology - 33

4.1.1.3 Climate - 34

4.1.1.4 Edaphic condition - 34

4.1.2 Resources development - 34

4.1.2.1 Forest resources - 34

4.1.2.2 Biodiversity resource - 35

4.1.2.3 Tourism potential - 36

4.2 SOCIO-ECONOMIC CONDITIONS - 37

4.2.1 Population - 37

4.2.2 Economy - 37

CHAPTER V RESULTS AND DISCUSSION - 39

5.1 MANGROVE MANAGEMENT AND ITS STRUCTURES IN STUDY SITES - 39

5.1.1 Mangrove structures - 39

5.1.2 Mangrove management - 46

5.2 SPATIAL-TEMPORAL DYNAMICS OF COASTAL MANGROVE EXTENT DURING 2000 -2015 - 47

5.3 KEY DRIVERS OF MANGROVE CHANGES DURING 2000- 2015 - 55

5.4 EFFECTIVE MEASURES TO IMPROVE THE MANAGEMENT OF MANGROVES - 58

CHAPTERVI.GENERAL CONCLUSION, LIMITATIONS AND FURTHER STUDY 64 6.1 GENERAL CONCLUSION - 64

6.2 LIMITATIONS AND FURTHER STUDY - 65 REFERENCE

APPENDIX

LIST OF TABLES

Table 3.1: Landsat data used in the study 23

Table 5.1 Plots information and mangrove characteristics in study site 40

Table 5.2 Plot Statistical tables 42

Table 5.3 NDVI values for mangroves and non-mangroves for studied sites different 47

Table 5.4 Mangrove area in studied sites in different years 47

Table 5.5 Accuracy of image classification in 2000 50

Table 5.6 Accuracy of image classification in 2006 50

Table 5.7 Accuracy of image classification in 2010 51

Table 5.8 Accuracy of image classification in 2015 51

Table 5.9 Changes in mangrove areas during periods 2000-2006, 2006-2010, 2010-2015 (ha) 52

Table 5.10 Mangrove changes in different periods 54

LIST OF FIGURES

Fig 2.1 Components of GIS (source: providencegissolutions.com) 15

Fig 2.2 Receiving, processing and applications of Remote Sensing Data (source: Canada Centre) 16

Fig 3.1: Flowchart of Landsat images classification and processing 28

Fig4.1 Study site (source: National Park Management, 2015) 33

Fig 5.1 Distribution of coastal mangroves in each year 2000, 2006, 2010, 2015 49

Fig 5.2 Mangroves changes Xuan Thuy National Park during the period of time 53

Fig 5.3 Mangrove changes in different periods 55

Chapter I INTRODUCTION

Xuan Thuy National Park is located at the estuary of the Red River in Nam Dinh province, about 150 km south-east of Hanoi, Vietnam The area was declared the country‟s first Ramsar site by the Bureau of the Convention on Wetlands of International Importance

3 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.Xuan Thuy national park (XTNP) is a vast wetland, which covers an area of about 7,100 hectares of the core zone, and 8,000 hectares of the buffer zone Endowed with rich alluviums, the park boasts a unique wetland habitat with diversified species of flora and fauna, especially migratory birds XTNP is the home for a total of 219 bird species belonging to 41 families and 13 orders, in which nine have been recorded as endangered species in the Red Data Book During the high migratory season, XTNP can attract 30–40 thousand birds, and hundreds

of bird watchers from all over the world come to the site (Statistic of Xuan Thuy National Park Management, 2010) As mentioned above, XTNP is divided into core zone and buffer zone, in accordance to National laws designated for national parks in Vietnam Management guidelines were specifically made for each zone, so that the core zone is a strictly protected area without any human activity allowed; and the buffer zone, adjacent to the core zone, acts as a transition area where activities are regulated to restrict and reduce adverse human impacts on the park The aquatic biodiversity of this wetland ecosystem provides food and wetlands-dependent livelihoods for the locals in the five communes in the buffer zone namely, Giao Thien, Giao An, Giao Lac, Giao Xuan and Hai, and other

communes in the neighboring areas Thousands of people from different backgrounds, regardless of gender, age, religion, and wealth, have been utilizing the wetlands daily for many years for aquaculture activities, especially shrimp and clam farming, and various aquatic harvesting activities Along with the fast growing population, there is an increasing pressure on these natural resources – being exploited for food, livelihood activities and other demands of not only over 45 thousand of local people but of people coming from other areas because products from the wetlands are being used locally, as well as being marketed to big cities and abroad Besides human activities, natural changes caused by sedimentation, water flow, climate change and sea level rise, are contributory factors adding more pressure and concern for XTNP management board in terms of fulfilling their mandates as a national park and a Ramsar site Consequently, Xuan Thuy has faced with various environmental and social issues that are threatening in the sustainability of resources and habitat for waterfowl Three major issues in XTNP were identified in thestrategic plan (2008), including (i) Negative changes and degradation of natural resources, (ii) Unsustainable livelihood practices of local communities, and (iii) Limited capacity of concerned institutions in wetlands management Though many problems are the result of external factors that the local have no or low control over, like global climate change, pollutants from upstream of Red River and National Laws, among others, local partners of the XTNP Network has acknowledged the fundamental issues that link directly to limited awareness and capacity of local authorities and communities (Statistic of Xuan Thuy National Park Management, 2010)

Although Xuan Thuy has been considered as a Ramsar site found only Vietnam, but the capital investment for the region is very relatively low with poor infrastructure, lack of equipment, the training of staff limitations From these difficulties, the management

of protected areas has not been effective and thus not meeting the conservation of

biodiversity The most dangerous thing is the plantations for the purpose of land reclamation and coastal protection in the flood plains, where land reclamation and coastal protection in the mudflats, where the species spoonbill foraging, Gull tank mines short, mine Bear fennel some endangered bird species on a global scale This makes fundamental changes of natural habitats and could turn the region into a place unsuitable for threatened bird species worldwide (Yu & Swennen, 2001) Moreover, the sand island in the park with

the salt marsh and sand dunes are also being planted Casuarina species introduction would

narrow the natural habitat in the region

Other factors affecting conservation in Xuan Thuy is strengthening up aquaculture farms can kill existing vegetation, while the fishing is not sustainable in the area tide may directly or indirectly disturb the endangered birds These factors arise due to the high population density in the coastal plain of Tonkin (population density in the buffer zone is

575 people / km2), lack of arable land and economic pressures However, they also reflect

a lack of awareness among key stakeholders of the value and economic ecology of the wetlands in the context of the growing sect

However, so far the forest management unit has yet to have an effective tool to support the management and monitoring of forest quality, accurately reflect the fluctuations in the areas of forest management, especially important areas like watershed With topographical features, climate and land use, the Xuan Thuy mangroves have extremely important role for the environment as well as socio-economic development of society Environmentally important forests contribute to climate regulation, ensuring ecological balance, reduce the devastation of natural disasters; Prevent soil erosion, groundwater protection; is a repository of important animal genetic resources donated With the development of economy and society of forests as sources of timber in service demand and productive life; Provide valuable products and forestry export commodities

contributing foreign exchange service through industrialization and modernization of the country; Provide your herbs have healing effects, human health performance Also mangroves Xuan Thuy are facing tremendous challenges that require monitoring efforts, regular management In the current conditions in Xuan Thuy, using the existing forces cannot meet the requirements necessary to have a system capable of providing oversight and management information is timely and continuous urgently needed set Along with the development of technology of earth observation satellites, the ability to apply remote sensing technology combined with geographic information systems in forest monitoring shows more advantages with special conditions of Xuan Thuy One of the environmental management tools are common in the world today that is GIS- Geographic information systems However, in recent years, new GIS really be interested and development in Vietnam This is to introduce topics and more widespread tool for field GIS environment sector Here the subject will introduce one of GIS tools that vegetation index NDVI in geographically remote sensing The secondary vegetation index separated from the near-infrared band, infrared and red strip intermediate parameters from which could see the different characteristics of vegetation such as biomass, index leaf area, photosynthetic capacity, total biomass products of seasonal plants can create These properties are related and depend greatly on the type of plant cover and weather, physiology, biochemistry and insect Technology for monitoring approximate characteristics of different ecosystems that allow identification standards and comparisons between them Multispectral satellite imagery, multi-resolution, including very large, repeat the cycle time to help gather information quickly, sync, objectivity is ideal for monitoring a number of factors affecting the forests in Xuan Thuy as temperature and humidity MODIS with 36 spectral bands specially designed, the extraction of information from MODIS requires an approach that has been repeated With this method, the method of assessment data and humidity surface

temperature from MODIS often based on theoretical models, as well as various experiments This is a technical one rather strange for users in Vietnam Stemming from

this reality, the students chose the project name is “Coastal mangrove change detection using mutil-temporal landsat data in Xuan Thuy National Park, Nam Dinh province during 2000-2015”.

Chapter II

LITERATURE REVIEW 2.1 GEOGRAPHIC INFORMATION SYSTEM (GIS)

2.1.2 Origins and evolution of GIS

GIS is explored in the 1960s from a mapping initiative work Canadian forest management GIS continues to be developed through the search of the researchers at the university and the government of Canada, the US and other countries aimed to introduce the geography of the Earth using a System computer database, display it on the terminal of the computer and mapping out the paper GIS market expanded strongly in the early 1980s thanks to the trade journals, conferences and professional collaboration to proclaim to the world about the benefits of GIS Today, there are hundreds of websites posted online GIS data on the World Wide Web Anyone can use the web browser can access and view GIS data

2.1.3 Composition of GIS

A geographic information system including hardware, software, data, human

people and methods These components must be consolidated further to cater to the effective use of GIS

Fig 2.1 Components of GIS (source: providencegissolutions.com)

- Display of data: GIS can allow the data stored and displayed complete information separately, at different rates; the level of detail of information is only limited

by the storage capacity of the hardware and software methods that used to display data

2.2 REMOTE SENSING TECHNOLOGY (RS)

2.2.1 Definitions

“Remote sensing is the art, science, talking less about an object without having to touch the object” (Ficher, 1976)

“Remote sensing is the science of extracting information from an object, measured from a distance away from the object does not need to come into contact with it Energy is measured in the current generation of remote sensing electromagnetic energy emitted from the object of interest ” (DA Land Grete, 1978)

2.2.2 The basic principle of Remote Sensing

Remote Sensing study objects by interpreting and separation information from air data snapshot, or by satellite image interpretation numeric The data below format photographs and digital images are obtained based on the recognition of radiation energy (photo frames and image) and wave feedback (photo radar) emitted from objects when surveying Energy in the form of electromagnetic spectrum, situated on different spectrum bands, and for information about an object from multiple angles will help decipher objects more accurately

Fig 2.2 Receiving, processing and applications of Remote Sensing Data (source:

Canada Centre)

Currently, there are many methods of digital image processing is done on the

part image processing software like IDRISI, ERDAS (PC), ERDAS Imagine (UNIX), PCI, ERMAPER, DRAGON, ENVI, ILWIS

2.2.3 Applications of Remote Sensing

Currently, remote sensing has been widely applied in many fields, many areas below is different and introduces the main application

- Climate and atmospheric gas studies (characterized ozone, clouds, rain, temperature, and atmospheric gas), Hurricane and climate research through data collection meteorological satellite - Research plants, forest Image Sensing provides research covers global government Botanists by day, season, year, month and phased Plant is the first object that satellite remote sensing image information acquired On remote sensing we can calculate biomass, maturity and index-based pest plants, forest fires can study through satellite imagery

- Hydrological Study: Water surface and the flow system is shown very clearly on satellite images and possible freezing of them Satellite image data, is recorded during floods, the data used to calculate the disaster area and the ability to forecast floods

- Research other planets: The data obtained from satellite remote sensing allowed study the stars and moon This confirms that remote sensing is a technology has immense applications beyond Earth

2.3 COASTAL MANGROVES

2.3.1 Definition of mangroves

“Mangrove forest is of tropical trees and shrubs has roots from saltwater deposits located between the coast and the sea areas” (Dr Nguyen Vinh Xuan Tien, 08/2008) Mangroves are distributed mainly in the Mekong Delta province of Ca Mau and two Northern provinces of Nam Dinh and Thai Binh

- Plants: mangrove flora including 47 plant families, the number of changes in each

different region, the northern coastal region has 52 species, 69 species of Central, Southern coastal area has 100 species

- Animals: there is currently no general study of the fauna of mangroves Vietnam Research on animals only stops at each local ecosystem

2.3.2 Mangrove forest characteristic

Mangroves have some common characteristics (Dr Nguyen Vinh Xuan Tien, 08/2008) as follows:

- Live in tropical, subtropical, equatorial

- Coastal and brackish areas, catchment estuary to the sea, inland valley swamps

- Have the effect of tidal ebb

- Areas with no big waves

- High humidity

They also have other impacts such as soil type and tidal regime

2.3.3 The role of mangroves

2.3.3.1 Ecological functions

- Reduction of environmental pollution, it helps to consume a significant amount of harmful emissions and increases the amount of oxygen for us To reduce the warming of the earth and prevent rising of sea water affect the lives of coastal residents

- Have an important role as biological 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 species protection work and estuarine coastal erosion and prevent harmful effects of storms and waves on the sea dyke system

- A good place to organize eco-tourism, training, research and teaching

2.3.3.2 Economic functions

Where economically profitable, providing a rich source of seafood for domestic use and export Alternatively, one could earn from other sources such as beekeeping for honey,

sell seedlings, bamboo exploitation, logging formwork from Casuarina trees and large

quantities of charcoal of the 51 plants have 30 species of forest wood supply, wood charcoal, tannin level and 14 species, 24 species can be used as green manure in agriculture, 15 species used as medicine men, 21 species beekeepers use cad 1 species can

be used as sugar wax (Dr.Phan Nguyen Hong, 1999)

2.4 APPLICATIONS OF GIS AND REMOTESENSING TO MANGROVE MAPPING

In Vietnam also had a number of research projects on mangroves In the research project "Application of Remote Sensing and GIS thematic mapping service integrated coastal management in Thanh Hoa province" by Nguyen Thi Bich Huong, Vietnam National University, Hanoi, 2012 have studied the exploitation and use of photographic documentation remote sensing in thematic mapping service of integrated coastal management Situation Analysis remote sensing and GIS applications in thematic mapping

in Vietnam and around the world Construction process technology established thematic maps based on remote sensing and GIS applications Collect and aggregate Remote Sensing Data, maps and other documents needed and build the database thematic coastal areas in Thanh Hoa province Deploy test established thematic

“Mangrove forest change monitoring using remote sensing and GIS, 2013 by Tran Trong Duc, Geo-Informatics Department, Faculty of Civil Engineering, University of Technology, Ho Chi Minh City, Vietnam Mangrove volatility over time can be monitored using analytical methods after sorting fluctuations In this method, first data multispectral satellite images of

mangroves each time it is conducting an independent classification Then use the GIS to detect fluctuations conducted by comparing images of the same area classification at two different times The method was applied to Can Gio district, Ho Chi Minh City

Chapter III STUDY GOAL, OBJECTIVES AND METHODOLOGY 3.1 STUDY GOAL, OBJECTIVES

3.1.1 Research questions

In this study, the research into three questions and a hypothesis will provide better understanding of the changes in coastal land, which can then inform coastal managers and planners and policy makers to reduce potential risks posed by both natural disturbances and human Research hypothesis is mangrove Systems in Xuan Thuy National Park has changed in 15 years The research questions are:

Question 1: How have the coastal mangroves have changed in Xuan Thuy National

Park over the past 15 years?

Question 2: What are the main drivers of change in coastal mangroves at Xuan

Thuy National Park?

Question 3: In order to better manage and protect coastal mangroves, what are key

solutions and lessons learned for Xuan Thuy National Park?

Objective 1: To investigate the status of coastal mangrove and management

schemes in Xuan Thuy National Park, Nam Dinh province

Objective 2: Monitor the coastal mangrove changes using multi-temporal Landsat

data in Xuan Thuy National Park from 2000- 201.5

Objective 3: To identify key drivers of coastal land cover changes over the last 15

years in Xuan Thuy National Park

Objective 4: To propose solutions for better management of coastal mangrove in

Xuan Thuy National Park and lessons learnt from this study

3.2 SCOPE OF THE STUDY

- Temporal scope: To achieve the study objectives a series of multi-temporal Landsat imagine from 2000 to 2015 is selected based on their availability on USGS website and qualities

- Time to study: From 01/08/2015 to 30/09/2015 at Xuan Thuy National Park, Giao Thuy District, Nam Dinh province

- Spatial scope: The entire coastal area of Xuan Thuy, Nam Dinh is selected for this study, including Xuan Thuy National Park, which is located in the southeast of Giao Thuy District, Nam Dinh Province, right at the mouth of the Red River Ba Lat The area of approximately 7,100 hectares the whole garden, including 3,100 hectares of forest land area and 4,000 hectares of mangroves Focusing on livelihoods of residents of commune: Giao Hai, Giao Xuan, Giao Lac, Giao An, Giao Thiên The average population density of

912 people / square km (according to the People's Committee of Nam Dinh province in 2010)

3.3 CONTENTS AND METHODOLOGY

3.3.1 Investigate the status of mangrove cover and its management schemes in Xuan Thuy National Park

Techniques and algorithms used to detect changes in the different phases of the objects on remote sensing have been established based on the development of remote sensing technology in the space characteristics, spectral, thermal and time Method to detect changes in mangroves is a way of comparing the differences between two images (Singh, 1989) In this study, NDVI (Normalized Differencing Vegetation Index) is applied

to detect changes in coastal mangroves and other coastal land use/covers Two pairs of images are used to analyze changes, including a pair of: 2000 - 2006, 2006 - 2010 and 2010- 2015

Remote sensing data for study:

The multi-temporal Landsat images were used in this study (Table 3.1) to assess the dynamics of the coastal mangrove area before and after the introduced policies The visual interpretation and unsupervised classification methods were used to map the coastal mangroves extent in 2000, 2005, 2010 and 2015 These maps are used to analyze the dynamics of mangroves through three periods, namely: 2000 - 2006, 2006 - 2010 and 2010- 2015

Table 3.1: Landsat data used in the study

Year Landsat image code Date Resolution Path/Row

Status of coastal mangrove management and mangrove structures

Investigate interviewed households to keep forests: The first job is to conduct direct interviews of households contracted for forest protection in coastal mangroves, targeting at those who were born and are living very closely to coastal mangroves Therefore, they have a very good understanding of coastal resources in studied sites Also, interviews are conducted with households who are assigned to protect and manage mangrove forests In addition, interviews with personnel are directly involved in the management of mangrove protection in areas such as ranger stations, social forestry officials, officials of the contracting unit to protect the forests in the area

Interview content generally refers to coastal mangroves that they have clearly known about mangroves, their local species and species appearance Recognizable species

such as Kandelia obovata, Rhizophora mucrolata can provide a clue for obtaining a high

accuracy when classifying images Also, this study gave the color photo or color drawings

to farmers for further clarity in the document; to identify species in order to provide more information about the venue, the growth of the species they are not aware of the consultation of experts

Field survey method (Appendix 01)

A questionnaire was conducted to interview the local people In this questionnaire:

• Target groups include: local administrators; communities who live in coastal zone Totally, 30 local households were chosen in each commune Giao Hai, Giao Xuan, Giao Lac, Giao An, Giao Thiên

• Collected information include: history, and the dynamics of the mangroves along the investigated time periods; The policies and projects about mangroves in Xuan Thuy National Park ; changing of livelihood through periods of time

Sampling method (stratified random sampling) and plot establishment)

Before plot establishment, this study was carried out a survey of vegetation in study areas and used visual interpretation on the Landsat images to determine location of plots

Stratified random sampling: A stratified random sampling is obtained by separating the

population elements into non-overlapping groups, called strata, then selecting a simple random sample from each stratum:

o Based on visual interpretation, plots were chosen randomly and distributed along the coastal side of mangroves area The coordinates of plots then were added into GPS devices before doing the fieldwork

Plot establishment:

o Totally, 4 square plots were conducted with the total area 600m2(30m x 30m) Each big plot had four sub – plots

30m

15m 30m

Data collection and analysis:

After plots establishment, we collected some basic data from plots, including: name

of species, number of species, height, canopy diameter, health situation to determine the quality and situation of mangroves forest We marked some key points with the assistance

of GPS devices The coordinates were recorded and integrated into ArcMap in ArcGIS software

Sample 1.Data collection survey.

Longitutude (Y): Location: Latitude (X): Date of survey: Investigator:

(m)

Counts RemarkScientific name Local

In this study, coverage ratio of each plot established also was calculated by counting step along the edge of control plots, then observing the coverage ratio for each step Finally, all the results were added after taking 100 steps so the study got the final coverage ratio for each plot

Mapping status of mangroves in different year 2000, 2006, 2012, 2015

Mapping the status of coastal mangroves and their distribution in different years are used this study Process of mapping the status of mangroves and classifying a single image

is illustrated

Digital map data

GIS map

Updating information

Post classification

Mangrove map: 2000,2006,2010,2015

Fig 3.1: Flowchart of Landsat images classification and processing

Step 1: Collecting data

Include Landsat images: 2000, 2006, 2010, 2015 and other imagine Landsat imagine take from http://earthexplorer.usgs.gov/ and other map is Data topographic maps, its take from Science and technology departments, Xuan Thuy National Park

Step 2: Landsat images processing

Grouping image bands: Landsat images obtained include individual spectral bands this means that many image channels had to be collected image interpretation This is the first task to process the image interpretation The satellite images obtained were in the form of various spectral bands in black and white To facilitate image interpretation and gain an increased accuracy, we had to combine the satellite images with colors for remote sensing images Improving image quality: The quality of the remote sensing image can be improved by the addition of a colored band again to increase the image resolution Cutting images to the boundaries of study areas: In particular, the obtained landsat images included

a broader area than the needed section for the analyses To save time in images processing and classification, we need to edit out the image part not included in study areas Then, a set of data (boundary of mangroves in Xuan Thuy National park) was used to split study area out landsat image

Step 3: Classifying Landsat images

This study was carried out using a number of different vegetation indices (NDVI)

to determine the current status of land cover and land use types coastal study area in 2000 and 2015 Additionally, subjects evaluate the degree of each different vegetation indices as the basis for selection of scientific image classification method based on vegetation indices

for the study area

Evaluate the precision and image processing after sorting Assessment accuracy of image classification: This step is used to assess the quality of the interpretation of satellite images or compare the reliability of the results obtained when applying different methods

in remote sensing classifying images After sorting Handling: After sorting process should perform post-processing to create the classification ability of the class map by generalizing

information.

Step 4: Mapping the distribution of coastal mangroves

Rules calculate the relationship between map scale resolutions of the sample is divided

by 1000 rate map to find out the size of the unit in m The formula for calculating the rate of resolution maps were developed as follows: The rate of maps = resolution (m) * 2 * 1000

Remote sensing data used in this subject spatial resolution is 30 m, according to the above formula; the rate of appropriate maps for the study area is 1:60 000 Additionally, to establish the complete map, adding details such as projection systems, annotations, ruler and compass orientation ratio

3.3.2 Quantifying coastal mangrove changes in Xuan Thuy National Park during 2000- 2015

Quantifying coastal mangrove extent in the different year:

Photos vegetation index NDVI is a special form of image ratio first suggested by Rouse et al, 1973, to emphasize the image area actually covered NDVI is a measure of the difference in reflectivity between the oscillation wavelengths For Landsat, NDVI vegetation index is usually calculated as follows (Equation 1)

NDVI = (NIR-Red / NIR + Red) (1)

Where: NIR near infrared channel Red is red channel

NDVI value between -1 and 1, with values from 0 to 0.5 is the region with sparse vegetation, 0.5 - 1 shows the dense vegetation and the value <0 indicates no vegetation

NDVI vegetation canopy and dense clouds will tend to have positive values (0.3 to 0.8).

- Water (such as oceans, seas, lakes and rivers) have a relatively low reflectance in both spectral channels (at least as far from the coast) and thus lead to a very low value or low NDVI

- Land usually represents a reflectance near-infrared spectrum than most with the red, and so tend to generate positive NDVI value is quite small (0.1-0.2)

- Very low value of NDVI (0.1 and below) correspond to barren areas of stone, sand, or snow

- Values represent moderate shrub and grassland (0.2-0.3)

- High value represents the temperate rainforests and tropical (0.6-0.8)

Quantifying the dynamics of coastal mangrove extents in each period

To identify the changes in coastal mangrove extent, the NDVI differencing is applied This technique compares and computes NDVI values between images acquired on two different dates In order to apply NDVI image differencing, the individual NDVI image of each date is generated with a range of values from -1 to +1 Histogram equalization enhancement is used to modify these values so that all values occurred with equal probability to range 0-255 for both images This step is followed by creating NDVI difference image through the subtraction of the NDVI image of one date from that on another date (Equation 2)

NDVIchange = NDVIyear 2 - NDVIyear 1 (2)

3.3.3 Identifying key drivers of coastal mangrove cover changes in Xuan Thuy National Park:

The main drivers of changes in coastal mangrove extent each period are identified through analyzing the relationships between the changes in coastal mangrove extent each period and other associated land use/cover together with field surveyed questionnaires

3.3.4 Proposing solutions for better management of coastal mangrove cover change in Xuan Thuy National Park and lessons learnt from this study:

To propose some possible solutions, this study was based on desire of local inhabitants and local administrators through interviews It included solutions about strategies to manage mangroves and other methods such as capital, communication.

Chapter IV STUDY SITE, NATURAL AND SOCIAL FEATURE 4.1 STUDY AREA

4.1.1 Natural characteristics

4.1.1.1 Geographical location

Xuan Thuy National Park is located in Giao Thuy District (Nam Dinh Province),

150 km south-east from Hanoi It is the largest coastalecosystem in the north of Vietnam and placed in the south of the Red River mouth The Core Zone has a total area of 7.100 hectares, 4000 hectares of low tide wetlands and 3.100 hectares of land It covers the islets of Con Ngan, Con Lu and Con Xanh Aquaculture farms and some parts

of mangrove forest cover the largest islet, Con Ngan Con Lu islet is covered by sandy areas as such as alluvial flats and aquaculture farms Con Lu, which is the smallest of the three islets is being widened by alluvium from the Red River and covered by sandy layer The Buffer Zone has a total area of 8.000 hectares The Park is a delta and estuary islands (Ba Lat river-mouth) support coastal mangroves and the mud flat ecosystem in the Red River delta The area includes land enclosed by sea dikes with fringing marshes „The land

is also noted for the human ecological model of VAC (model of planting vegetable gardens, raising fish in ponds and animal husbandry all in one home) The area has a long history of wet rice cultivation as well as dike construction and land reclamation (Statistic

of Giao Thuy District‟s government, 2013)

Fig4.1 Study site (source: National Park Management, 2015) 4.1.1.2 Topography and hydrology

Xuan Thuy National Park is located in the coastal area of the Red River basin, at the mouth of the Red River empties into the sea, known as the Ba Lat Reserve includes dunes and interspersed among them are the mudflats Con Ngan is the largest sand dunes,

on which primarily aquaculture ponds and mostly covered with mangroves Con Lu includes a vast sandy beaches, mudflats and marshes and a small area of aquaculture ponds Con Xanh is dunes smallest thin layer of sand and continue to cultivate by silt from the Red River offers Green and Con Lu often flooded in high tide The southern boundary

of the park is the Vop river mouth In protected areas, where the highest absolute height of

3 m, and the deepest seas of 6 m

4.1.1.3 Climate

Giao Thuy district lies in the tropical monsoon region, which has two distinct seasons One hot and rainy season from April to October and a cold and dry season from November to

March The annual average temperature is 24 °C The highest temperature in summer is 40.3

°C and the coldest temperature in winter is 6.8 °C The average humidity is 84% The annual rainfall is between 1700 mm and 1800 mm averagely there are 133 rainy days per year Rain mainly falls in summer or winter With 15-18 rainy days August is the month with the most rainfall in contrast to autumn and winter with the lowest rainfall (25–50 mm per month) From July to October the Red River is flooded, which influences the region as well as the northeast monsoon In winter the wind mainly comes from the north and in summer from the east July and August seem to be the stormiest months in the year where storms are followed

by heavy rain Three strong storms hit the north of Vietnam in 2005 (28 July one wind with level 7, 18 September with level 9 and on 28 September with level 12)

4.1.1.4 Edaphic condition

There are two types of soil formed from the alluvium of the Red River One isalluvial mud (which becomes loam) and one is sand Transported by water the alluvial forms the coastal soil like light soil (sand and light loam and pure sand), medium soil and heavy soil (loam and clay) Soil of the area is made up of silt of Red River and East Vietnam Sea

4.1.2 Resources development

4.1.2.1 Forest resources

Were recorded in the study area in Xuan Thuy National Park with the distribution

of 115 species of vascular plants, including the main mangrove species and the species

involved in the mangrove forest, species from inland migration to and adapt to conditions

at Xuan Thuy National Park of 101 genera, 41 them Among them, the Polypodiophyta has seven species of 7 genera, 5 families; two cotyledons-Dicotyledones class has 80 species, belonging to 70 genera, 30 them; a cotyledon-Monocotyledons class

fern-has 28 species belonging to 24 genera, 6 families The number of plant species recorded in Xuan Thuy National Park in this report lower than manual data Phan Nguyen Hong (2007) (192 species on the expenditure of 60 145 vascular plant them) by excluding the species of agricultural ecosystems or neighborhoods in five communes in BZ-national dike Xuan Thuy National Park, there are 07 species of plants directly involved in the mangrove forest

that is Aegiceras corniculata, Sonneratia-Sonneratia caseolaris, Kandelia obovata, Rhizophora stylosa, Acanthus illcifolius , Acanthus ebracteatus, trumpet-Derris trifoliata Wire toad.

4.1.2.2 Biodiversity resource

Xuan Thuy has 14 types of habitats, including the natural habitats and artificial habitats (Pedersen and Nguyen Huy Thang 1996) Habitat valuable highest biodiversity is the mudflats and mangroves naturally less affected Plants advantage in that mangrove

species belong to the Chaldean Kandelia In areas with a few trees planted Sonneratia caseolaris There are also teas Aegiceras corniculatum and Acanthus species grow naturally ilicifolius scattered throughout the region (Pedersen and Nguyen Huy Thang

1996) Many mangrove forests covering mature aquaculture farms, but there are also many large areas of mudflats have been planted with monoculture page In 1996, 300 ha of

Phragmites sp Aquaculture in the lagoon area of Con Ngan (Pedersen and Nguyen Huy

Thang 1996) However, until 2000 the reed beds disappeared (According to J Eames,

2000) On Con Lu, Casuarina equisetifolia was planted Cassuarina large area, this is an

important habitat for migratory birds of the forest Due to the diverse and relatively intact

condition of the habitat, the park is the place to stop and important wintering of migratory water birds Through the survey of 1988 (Scott et al 1989) and 1994 (Pedersen et al 1996) has observed over 20,000 individual birds in the region Middle Spring 1996, there are over 33,000 sea birds flying over national parks (Pedersen and Nguyen Huy Thang 1996)

XTNP is the place regularly recorded eight birds are threatened and near threatened

on a global scale, that is: Spoonbill Platalea minor, White Stork China Egretta eulophotes, large Redshank Tringa guttifer gold mine, Gull Larus pool short beak saudersi, spot-billed pelican Pelecanus philippensis, mine Bear Calidris pygmeus spoon, Mycteria leucocephala, large Dowitcher Limnodromus semipalmatus (Tordoff 2002) Noting the

most remarkable in Xuan Thuy populations exist largest Spoonbill in Vietnam, in a few years, the largest number to be officially recorded in the region of 65 individuals (Nguyen Duc Tu, 2003) Moreover, Xuan Thuy gathering place, important stopover for many

species of migratory waterfowl popular in winter as black tail straight Choat Limosa, Redshank Tringa erythropus red legs and large Choat Eurasian Curlew Due to the

international importance of the conservation of birds, Xuan Thuy has been recognized as one of the important bird areas in Vietnam (Tordoff, 2002)

4.1.2.3 Tourism potential

Ecotourism community buffer zone of Xuan Thuy As one of 05 communes in the buffer zone of the National Park (NP), Xuan Thuy, Giao Xuan bring lots characterizes the coastline area with mangroves, mudflats feed aquaculture, moderate climate, hospitable people and it also kept the unique cultural characteristics typical of residents of the Red River delta All gave Giao Xuan outstanding advantages to become demonstration sites Ecotourism based on community

4.2 SOCIO-ECONOMIC CONDITIONS

4.2.1 Population

According to statistic in 2014 of Nam Dinh province‟s government, population in Giao Thuy was 51,109 people, 13,740 households Average population density was greater than 6,546 people/km2 Number of households who were farmers accounted for 2,175 people, fisherman accounted for 676 people Number of people in working age accounted 25,771 people Giao Thuy is one of district in Nam Dinh province which has high living standard In

2008, average income was 9 million VND, increased 50.8% in comparison with 2000

4.2.2 Economy

In recent years, according to statistic of Nam Dinh province‟s government, thanks

to the innovation of management mechanism and economic policy of the State, along with the leadership of the Party, government, economy Giao Thuy district on a development, maintain growth rate high growth In five years (2006-2010) economic development rather, the value of total product per capita rose 10.71% / year The economic structure is a positive shift towards increasing the value and income, reducing the share of agricultural sector - forestry - fisheries; the proportion of industry - construction 14%; Services account for 38%; agriculture - forestry - fishery 48% Per capita income in 2010 reached 11.2 million / person / year

+ Agriculture - forestry - fisheries: gradually developed towards production of goods and increase the value of 1 unit of arable land Total per capita food production: 101

166 tones / year Value production / ha cultivated reach 66.7 million The production value

of agriculture - forestry - fishery increased on average 3.5% / year Structure of agriculture

- forestry - fishery has shifted towards increasing the proportion of animal husbandry and fisheries, particularly the fisheries sector with an average growth rate of 15.15% / year

+ Manufacturing industry - handicraft industry: manufacturing industry and small industry has grown quite, the average growth rate of 18.91% / year, the production scale of

enterprises gradually expanded Several major products have high growth rate as an average sauce 934 000 liters, 13 588 tons of iodized salt, clothier 1,319 thousand products, Earthenware 97 812 thousand members The mechanics, repair, shipbuilding, wood processing, production of construction materials, textile, knitting, embroidery, food processing, food has contributed to encouraging growth to create jobs for workers, poverty alleviation increased revenues for local budgets

+ Production of salt: In 2010, a total area of 482 hectares with salt over 9,000 employees involved in manufacturing, the annual supply of 42,000 tone market, the value

of total income over 65 billion In addition, the district has also developed 8 base salt harvesting of salt for the manufacture and processing of clean salt, iodized salt for domestic consumption and export to Laos

+ Industry rural district currently has 1,325 manufacturing establishments and households in rural occupations, 5 villages, attracting over 7,000 workers involved with the main production facilities are: Rattan stretch, Crochet, Embroidery, mushroom production, food processing, food, textiles, carpentry, mechanics, construction Rural trades with the manufacturing base is diverse, rich but owners weak at small scale, mostly spontaneous, initially without the basic techniques, learning, just handing, just do mainly postmortem actual tastes associated with demand for commodities market production development The total value of 5-year average production reached 117.6 billion / year; the average growth rate of 13.5% / year

+ The service sector: Total retail sales of goods in 2010 reached 493.6 billion, up 152% compared to 2006 The market commodity rich, vibrant meets the requirements of production and life The transportation services industry, postal - telecommunications, finance - credit, tourism - trade thrive: production value in 2010 reached 414.2 billion,

an average annual growth rate 12.8% / year Which tours in Quat Lam resort achieved average revenue of billion /year Currently there are 42 hotels, motels, tourist service kiosks 111, annual average welcomed 172,000 visitors

Chapter V RESULTS AND DISCUSSION

5.1 MANGROVE MANAGEMENT AND ITS STRUCTURES IN STUDY SITES

5.1.1 Mangrove structures

Mangrove features

Coastal mangroves are stretching along southeast of Nam Dinh, distributing mainly

in the coastal communes of Giao Thuy district Mangrove areas has 7100 ha over the tidal mangrove areas( statistic of Xuan Thuy National Park Management, 2014) Beautiful scenery is very convenient for sightseeing, eco-tourism and attracting investment projects and aquaculture As a result shown that study sites with mangroves are often muddy, low oxygen levels, high water level and low salinity with slow tide

As the result of field survey showed that there were three main mangrove species

identified, namely Kandelia obovate and Aegiceras corniculatum, Sonneratia caseolaris Besides, Sporobolus virginicus - Scirpus kimsonensis in Ba lat mouth on mud tidal; Clerodendron inerme - Hibiscus tiliaceus - Ecoecaria agallocha on higher land, pond bank less effect of tidal; Datura metel - Ricinus communis - Ruellia tuberose community which distributed on higher land, top of dikes without or less effect of tidal; Casuarina equisetifolia community which concentrated on sand dunes outside mangroves forest such

Con Lu,Con Ngan (Giao Thien Commune), Nha (Giao Xuan commune) and other area;

Halophila ovalis - Halophila minor - Myriophyllum dicoccum community on brackish land; Cyperus malaccensis - Phragmites karka community on aquatic pond; Aegiceras corniculatum + Sonneratia caseolaris + Avicennia marina + Acanthus ilicifolius community; artificial Kandelia obovata - Aegiceras corniculatum community and A.corniculatum - Avicennia marina community

Further field survey and interviews about 30 household in Giao Thuy district in