ST'RUCTTOU. OF BRACKYURA ORGIES IK, mangrove Al^EA OF )aye reserved FOREYT, , >\vA ' DELTA

PbD (PI&SEiaTATION').

THET SU MiVR

DEFARTKffiNT ZOOLOGY UNIVERSITY oF'YANGON MYANlVlAR

FEBRiJA#^^ 2010

- •—-•'-"'mini COMMUNITY STRUCTURE OF BRACHYURA CRAB SPECIES IN MANGROVE AREA OF PYINDAYE RESERVED FOREST, AYEYAWADY DELTA

PhD (DISSERTATION)

THET SU MAR

DEPARTMENT OF ZOOLOGY

FEBRUARY, 2010 community structureof brachyuracrab species IN MANGROVE AREA OF PYINDAYE RESERVED FOREST, AYEYAWADY DELTA

tTARTC

THET SU MAR

this dissertation is SUBMITTED TO THE BOARD OF examiners in zoology, UNIVERSITY OF YANGON FOR the DEGREE OF DOCTOR OF

referee CHAIRPERSON EXTERNAL EXAMINER Dr. Swe Thwin Dr. Maung Maung Gyi Dr. Zaw Professor / Head Professor / Head (Retired) General Manager Department of Marine Department ofZoology Myanmar Tasaki Co. Ltd University University ofYangon

SUPERVISOR CO-SUPERVISOR id Dr. Khtn Maung Swe Dr. Thein Thein Htay Professor Lecturer Depaitment of Zoology DepartmentofZoology Dagon University University ofYangon ACKNOWLEDGEMENTS

I would like to express my profound gratitude to Dr. Maung Maung Gyi, Professor, and Head of Department of Zoology, Yangon University for permitting to conduct this research. 1 especially thank my supervisor. Dr. Khin Maung Swe, Professor of Department of Zoology, Dagon University for his guidance and valuable discussion throughout this study. I next extend my gratitude to Daw Myint Thida, Head of Department of Zoology, Defence Services Medical Academy, Yangon, for her departmental permission and facilities. This study was supported by Nagao Natural Environment Foundation (NEF), Japan, as a scholarship in cooperation with the Forest Resources Environment Development and Conservation Association (FREDA), Yangon, Myanmar. I am grateful to the Association and the Foundation for their financial support during the period of study. Thanks are also extended to FREDA/ACTMAN Project Manager and staffs for their needful assistance. I also grateful to U Ohn, General Secretary, FREDA, Myanmar and Dr. Takaheru Kotsuge, Researcher, ISME Research institute ofOkinawa, Japan, for their suggestions, assistance and encouragement during the period of study. I also appreciate Dr. Maung Maung Than, Project Manager, FREDA/ACTMAN project. Forest Resources and Environmental Development Association, Myanmar for kind advice on study of the mangrove forests and valuable suggestions. Gratitude is owed to UAung Myint, General Secretary, Renewable Energy Association of Myanmar, for his advice on how to approach the research subject and for his encouragement during this work. Sincere thanks go to Dr. Cherry Aung, Lecturer, Department of Marine Science, Mawlamyine University for her keen interest in my work and help in preparing ofthe manuscript. Finally, my deepest gratitude is due to my beloved parents who had nutured, educated and guided me to attain my goal in life as an educated person. My heartfelt appreciations also go to my dearest husband and all my family members for their understanding, encouragement and financial support without which this work could not be accomplished.

11 ABSTRACT

Community structure of brachyuran crabs in different mangrove forests of Pyindaye reserved forest, Ayeyawady Delta were conducted from year 2006-2009. A total of 12 sampling sites were based on Kamaurhouk Creek and Pyindaye Kabyut Creek. The samples were collected from ahd four study sites on the creeks related with different habitat types consisting a degraded forest,a denuded forest, a mono and a mix plantation forests by using lOOm^ (10m xlOm) quadrates. Another eight study sites randomly selected on the creeks, related with different mangrove community forest types i.e. Avicennia offinalis community, Avicennia alba community, Avicennia YYiavivia community, Sovicratia cascolavis community, ExcoQcavia acholocha community, Herietera fames community, Rhizophora apiculata community and Ceriop decandra community by using 100m2 (10m x10m) quadrates. A total of 27 crab brachyuran species belonging to 9 genera and 3 families were recorded including a higher carnivore, 3 lower carnivores, 12 omnivores and 11 detritivores. Among those, family Grapsidae was the most diverse group represented by 12 species. The species Varuna littreta had highest abundance followed by Sesarma minutum and Sesarma edwarsi in the study area. Regarding to the different habitat types, highest abundance of crabs were observed in the degraded forest type representing 552 individuals followed by mix and mono plantation forest types representing 273 and 224 individuals respectively and the lowest abundance was noted in denuded forest type representing 27 individuals. Regarding the forest community type, the highest abundance was observed in Rhyzopora apiculata community representing 458 individuals followed by Avicennia officinalis community representing 398 individuals and the lowest abundance occured in Exocoecaria agalocha community representing 160 individuals. Seasonal variations were encountered representing 770 individuals in hot season, 1191 in wet season and 1729 in cool season. Distribution, diversity, dominance, trophic status and correlation of the species were also evaluated. The main purpose of the study was to know the community structure of the brachyuran crab species related with different community and habitat types of mangrove ecosystem.

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