Summary of doctoral thesis in Biology: Study on species composition and distribution characteristics of freshwater crustaceans (crustacea) in Phong Nha - Ke Bang national park area

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MINISTRY OF EDUCATION
AND TRAINING

VIETNAM ACADEMY OF SCIENCE
AND TECHNOLOGY

GRADUATE UNIVERSITY SCIENCE AND TECHNOLOGY

-------------***-------------

LE DANH MINH

STUDY ON SPECIES COMPOSITION AND DISTRIBUTION
CHARACTERISTICS OF FRESH WATER CRUSTACEAN
(CRUSTACEA) IN WATER BODIES OF PHONG NHA –
KE BANG NATIONAL PARK

Major:

Zoology

Code:

9 42 01 03

SUMMARY OF BIOLOGY DOCTORAL THESIS

HÀ NỘI – 2018

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This dissertation is submitted to the Committee of the Graduate
University of Science and Technology

Supervisors: 1. Asc. Prof. Dr. Ho Thanh Hai
2. Dr. Tran Duc Luong

Referee 1:
Referee 2:.
Referee 3:

The research has been carried out
at the Graduate University of Science and Technology
Date of Oral Presentation:……,…../……../2018

Copy of this dissertation is available:
National Library of Viet Nam
Graduate University of Science and Technology


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INTRODUCTION
1. The necessity of the research
The Decapodal, Copepoda, Cladocera and Ostracoda taxonomy are
the popular species of crustaceans in freshwater in general, and in the
water bodies of karst in particular. The biodiversity of these groups is
reflected in the abundance of the species, number of individuals and
distribution in the community. They play a major role in the food chain
and food net of aquatic ecosystem. Many species are economically
exploitable.

In the world, many studies on the fauna in general and the freshwater
crustaceans in the water bodies of karst in particular, including cave
underground water were realised with interestingly results which many
new genus and species have been found.
In Vietnam, for the topographical karst in general and the limestone
mountains of Phong Nha-Ke Bang National Park in Quang Binh Province
in particular, especially for underground water bodies in the cave
underground water bodie there are very few research on biodiversity
characteristics, species composition of the aquatic fauna in general and the
crustacean group in particular.
Previous studies on the environment and aquatic life in the Phong
Nha-Ke Bang National Park have recorded 33 freshwater crustacean
species, of which 12 species are found in the Phong Nha cave. Of the
species found in the river in the Phong Nha cave, two new Calanoida
crustacean species for science are described. These new species and genus
are currently being considered endemic to Vietnam.
Certainly, these above results have not fully reflected the species
composition and distribution characteristics of freshwater crustaceans in
the topographical karst, espcially the cave underground water in the karst
of Phong Nha-Ke Bang. Therefore, we propose the research topic: "Study
on species composition and distribution characteristics of freshwater
custacean in water bodies of Phong Nha-Ke Bang National Park".
2. Objective
- Having sufficient data on the leading component of freshwater
crustaceans in waters bodies of Phong Nha-Ke Bang National Park


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- Determining of the quantitative distribution of freshwater
crustaceans in the study basins, along with the variability of this group in

spatial and climatic seasons.
- Proposal of measures for conservation and sustainable use of
freshwater crustaceans resources in study area
3. Contents
3.1. To identifying the species composition of freshwater crustacean
of the Calanoida, Cyclopoida, Harpacticoida (Copepoda), Diplostraca
(Cladocera), Podocopida (Ostracoda), Amphipoda, Isopoda và Decapoda
in the study area.
3.2. To comparing the number of species and composition of species
in different water bodies, especially in groundwater and underground
waters in the cave.
3.3.To determining the number of individuals of the studied species
in the water bodies, and to consider the dynamics of their density in each
type of water body in spatial and climatic seasons.
3.4.To studying the relationship between the basic characteristics of
water environment (to, pH, DO, salinity ...) of the watershed and some
biological parameters of freshwater crustaceans.
3.5. To proposing solutions for preservation and sustainable usage of
wetlands and freshwater crustaceans in the study area.
Chapter 1. LITERATURE
1.1. Studies on freshwater crustacean in the world
1.1.1. Studies on the classification of freshwater crustacean groups
1.1.1.1. Freshwater Copepoda
Müller (1776), Jurine (1820), Milne-Edwards (1840), Brady (1883)
did have the studies on taxonomy for Freshwater Copepoda based on
morphological characteristics. Currently, in the world there are about
24,000 species of 2,400 genera and 210 families described. Among them,
there are about 2,800 species of fresh water inland (Boxshall and Halsey,
2004; Boxshall and Defaye, 2010)
In Malaysia and Indonesia there were the research works of Douwe

(1901, 1907), Daday (1906), in Java and Sumatra; Fernando (1978) on
Copepoda fauna in Malaysia. The research on the species in Cambodia
was published from studies of Brehm (1951, 1954). The freshwater
Copepoda of Thailand is investigated the most thoroughly from the


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studies of Boonsom (1984), Chullasorn et al. (2008). Shen, et al. (1979)
described 206 species of Crustacea Copepoda of inland waters of China.
1.1.1.2. Freshwater Cladocera
Cladoceran was studied very early by Muller (1776, 1777, 1785) with
a genus was first published.
It can be said that the study of Lilljeborg (1901) described and drew
illustrated of 102 species with a system Cladocera taxa in the most
successful at that time. According to Martin and Davis, 2001, about 620
species were known as freshwater Cladocera ranked in four sets:
Anomopoda (537 species), Ctenopoda (50 species), Haplopoda (one
species) and Onychopoda (32 species)
In Southeast Asian, the prominent works are of Richard (1891, 1895,
1896), Johnson (1956), which were realised in the island Java, Sumatra
(Indonesia). In Malaysia, there were many studies realised by Johnson
(1962, 1963, 1965, 1975), Idris (1983). In Thailand, there are studies by
Boonsom (1984), Sanoamuang et al. (2001), Maiphae et al. (2005). Lastly,
Chiang and Du (1979) have listed 136 species in 45 genera and 10
families in China.
1.1.1.3. Freshwater Ostracoda
Studies on Crustacea Ostracoda taxonomy had been started in 17771778 by Muller. According to Martens et al. (2008), there were 2,000
species of inland freshwater crustaceans in Ostracoda that have been
recorded all over the world, most of them are free-living, only about 12
species of parasitic live, all belonging to the Podocopida

According to Fernando (1982), there are 87 species of 26 genus
recorded in Southeast Asia (Malaysia, Indonesia and the Philippines).
Recently, Savatenalinton & Martens (2010) has a comprehensive research
on the species composition of the Cypricercinae subspecies and describe
six new species in this area.
1.1.1.4. Freshwater Decapoda
Since the mid-nineteenth century, many studies on freshwater
shrimps and crabs have been conducted in countries in Europe and Asia.
According to De Grave et al. (2008), there were about 2,500 species
of Caridea shrimp belonging to 31 families, living in saltwater, brackish
and freshwater. Of these, about 655 are freshwater species. There were
1,476 species of freshwater crabs known in the world distributed in all
geographic regions of animals, including 1,306 pure freshwater species.
The two most abundant species were the Potamidae (505 species and 95


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genera) and the Gecarcinucidae (344 species and 59 species), which were
concentrated in Southeast Asia and South Asia. (Cumberlidge et al.
(2009).
According to Cumberlidge et al (2009), there were 10 countries with
the largest number of freshwater crab species, of which 8 are in Asia:
China (224 species), Thailand (101 species), Malaysia (92 species), India
(78 species), Sri Lanka (50 species). In other countries, although not yet
fully registered, have recorded relatively large number of species, such as
Indonesia (83 species), Philippines (42 species), Vietnam (40 species).
1.1.2. Studies on the habitat and distribution of ecological groups
living in water bodie in karst
1.1.2.1. The water bodies of karst
Based on topography, hydrology, and water environment, the

limestone karst can be divided into three major groups, including: Lotic
Environments, Lentic Environments, Underground Aquatic Environments
1.1.2.2. The division of groups of living organisms in the aquatic
environment
Today, in the study of cave fauna, Schiner-Racovitz's classification
system of the species of underground organisms is widely accepted and
used: "Trogloxenes" includes species get lost or attracted to the humidity
or food sources of the cave, but they do not always live in this
environment and do not reproduce here. "Troglophiles" consist of living
animals in the habitat underground, usually in shallow areas and caves;
they also spawn here. However, these species can also be found in
terrestrial environments. "Troglobites" consist of live animals in dark
environments in deep soil or in caves. They deeply transform the
biological and ecological features that adapt to the environment. Their
entire life cycle start & end in this area and can not be found on the
ground.
1.1.3. Crustacean species composition in fresh water areas in karst
In South East Asia, there many studies had been realised by Ng
(1988, 1991, 1992, 1996); Ng & Naiyanetr (1993). Camacho (2005)
described two new genera with two new species (Paraeobathynella
vietnamensis, Sketinella trontelji.) in Vietnam. Camacho et al (2011)
described 1 new genus with 1 new species (Siambathynella laorsriae) in
Thailand. Victor & Fernando (1981) describes a new subfamily, a new
species of Ostracoda from Batu, Malaysia. In Copepoda, there are studies


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by Menzel (1926), Chappuis (1931); Bruno & Cottarelli (1999), Pesce &
Apostolov (1985); Brancelj et al. (2010) and Watiroyram et al. (2012)
According to Stoch & Galassi (2010), 4,775 species of invertebrates have

been recorded in cave basins around the world, of which the number of
crustaceans accounts for most known species, including 3,400 species,
contributes up to 71.2% of total species. In which the Copepoda group has
about 1,000 species, the Ostracoda group has about 300 species, the
Amphipoda group has about 950 species, the Bathynellacea group has
about 200 species, and the Decapoda group has about 300 species.
According to Bracelj et al.(2013), in Southeast Asia, 102 species of
freshwater crustaceans have been recorded in the groundwater aquifers:
most of which are Decapoda (34 species), Copepoda (23 species), Isopoda
(21 species), Amphipoda (13 species), Syncarida (5 species),
Thermosbaenacea (3 species) and Ostracoda 1 species. According to
statistics, the Philippines has the largest number of species with 34
species, Thailand (24 species), Indonesia (17 species), Malaysia (14
species), Vietnam (9 species), Cambodia (3 species), Laos (1 species) and
Myanmar have not recorded any species in this crustacean group.
From 2013 to 2016, the reseachers continued to study and published
10 new crustacean species in Southeast Asia, including Vietnam: 3
species of shrimp, crabs of Decapoda family (Do & Nguyen, 2014). Ng &
Vidthayanon, 2013; Cai & Vidthayanon, 2016), 6 species of Copepoda
(Tran & Chang, 2014; Tran & Hołyńska, 2015, Boonyanusith et al., 2013;
Watiroyram et al., 2015a, 2015b, 2016), a species of Thermosbaenacea
family (Rogers & Sanoamuang L, 2016).
1.2. The study of freshwater crustacean in Vietnam
1.2.1. Reseach on taxonomy
1.2.1.1. Copepoda and Cladocera
Prior to 1945, studies on the composition of the microcrustacean in
Vietnam were mainly done by foreign authors.
From 1960 up to now, many studies had been realised by Dang Ngoc
Thanh (1965, 1977, 1980); Dang Ngoc Thanh, Ho Thanh Hai (1991,
1992, 2001). In 2001, Dang Ngoc Thanh and Ho Thanh Hai described the

classification of 50 species of Cladocera and 31 species of Copepoda.
Then there were studies by other authors such as Reid and Kay
(1992), Hołyńska and Vu Sinh Nam (2000), Tran Duc Luong and
Hołyńska (2015). Ho Thanh Hai, Tran Duc Luong (2007, 2008, 2009).


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Tran Duc Luong (2012) recorded 105 species of Copepoda belonging to
45 genera, 13 families, in 3 oder of Calanoida, Cyclopoida and
Harpacticoida. Among them, Calanoida has 39 species, Cyclopoida oder
has 29 species, Harpacticoida has 37 species in the inland waters of
Vietnam.
1.2.1.2. Ostracoda
In Vietnam, the results of research on Ostracoda are very limited.
Only one species was recorded by Brehm (1952) in Hai Duong. Dang
Ngoc Thanh et al. (1980) described the taxonomy of eight species of the
Cypridae family in fresh water bodies of North Vietnam.
1.2.1.3. Decapoda
Freshwater crayfish (Decapoda) in Vietnam was studied by Edwardo
from 1869.
On freshwater shrimps, the works of Bouvier (1904, 1920, 1925),
Sollaud (1914), recorded only five species in Vietnam including two
species of Coutierella tonkinensis and Leander mani and three species of
Atyidae: Caridina nilotica typica, C.weberi sumatrensis and C. tonkiensis
In the period from 1945 to 1975, in the North of Vietnam, there were
studies by Dang Ngoc Thanh (1961, 1967), Dang Ngoc Thanh and
Nguyen Huy Yet (1972). In 1975, Dang Ngoc Thanh presented a list of 27
species of shrimp and crab found in the waters of North Vietnam. On
freshwater shrimp, Dang Ngoc Thanh et al (1980) had documented and
described eight new Caridina species; Then there were the authors N. X.

Quynh, Peter, K. L. Ng and Liang X. Q. (2002). Dang Ngoc Thanh, Do
Van Tu (2007, 2010) described six new species Atyidae for science in
Vietnam. In the South there were some studies which had been realised by
Nguyen Van Xuan (1978, 1979, 1981, 1992, 2003, 2004, 2006, 2010,
2011).
On freshwater crabs, Dang Ngoc Thanh and Tran Ngoc Lan (1992)
described two new species of the genus Orientalia (Orientalia rubra,
O. tankiensis) from specimens collected in Nghe An and Thanh Hoa. Ng
(1996), Peter, KL Ng & Darren, CJ Yeo (2001), Tohru Naruse, N. X,
Quynh and Darren CJ Yeo (2011) continued to document and describe
some other freshwater crab species in Vietnam.
Dang Ngoc Thanh and Ho Thanh Hai (2012) provided a list of 42
species of shrimps and 36 species of crabs recorded in Vietnam.
Do Van Tu et al. (2015) described a new genus and species in Vinh
Tan, Binh Thuan province (Binhthuanomon vinhtan); Do Van Tu, Nguyen


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Tong Cuong and Le Hung Anh (2016) described a new species of crab
found in Huong Pagoda (Indochinamon Chuahuong); Hsu-Te Shih &
Chao Huang (2016) described a new species of crab found in streams in
Ha Lang District, Cao Bang Province (Tiwaripotamon pluviosum).
According to data to date, Vietnam has recorded 43 species of shrimp and
41 species of freshwater crab.
1.2.2. Research on freshwater crustaceans in the karst of Vietnam
In 1967, Borutzky record seven species of Harpacticoida (Copepoda)
in the Viguierellidae and Canthocamptidae families. Subsequent studies of
Camacho (2005), Brancelj (2005), Apostolov (2007). Tran Duc Luong et
al (2011) recorded 39 species crustacean of Copepoda (18 species),
Cladocera (12 species), Amphipoda and Decapoda in Trang An - Ninh

Binh limestone area. Tran Duc Luong and Cheon Young Chang (2012)
announced two new species for science: Microthridion thanhi, Nitokra
vietnamensis.
In the Phong Nha-Ke Bang karst area, some studies realised by Dang
Ngoc Thanh and Ho Thanh Hai (2001) described two new species
belonging to Calanoida in the underground river section of Phong Nha
cave; Ho Thanh Hai et al. (2003) provided a list of species of aquatic
organisms (phytoplankton, zooplankton, zoobenthos and fishes) in Phong
Nha cave, including 12 species of microcrustacea (Copepoda and
Cladocera) found in the river in the Phong Nha cave.
Tran Duc Luong and Cheon Young Chang (2012) described a new
Cyclopoidae in Thien Duong Cave. With the group of shrimps and crabs
(Decapoda), Ng (1996) recorded a new species and genus of crab
(Nemoron nomas) in the Dark Cave (Phong Nha - Ke Bang). In 2014, Do
Van Tu et al described a new species of crayfish (Macrobrachium
phongnhaense) in the Va cave of Phong Nha-Ke Bang National Park.
1.3. Studies on Phong Nha - Ke Bang karst
This part presents an overview of geography, climate, weather and
hydrology in the study area.
Types of water bodies in Phong Nha-Ke Bang karst.
Based on differences in hydrological morphology, hydrological and
water environment, it is possible to divide the types of water bodies in
karst of Phong Nha - Ke Bang range into main types such as: streams,
rivers, small floodplains seasonal are located in low tide, reservoirs and
underground cave systems.
Underground water in the cave


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Based on survey data, drawings of caves in the limestone mountains

of Quang Binh by Tran Nghi et al. (2003), Limbert (2012), conditions of
hydrological and environmental. Accordingly, the water bodies in the
karst mountain cave in Quang Binh can be divided into four main types:
Water flows in the interstitial; underground river in the cave; puddle of
temporary water reservoir and underground lake in the cave.
CHAPTER II. OBJECT, LOCATION, TIME AND
METHODOLOGY
2.1. Objects and scope of research
- Objects of study: Freshwater crustaceans of the Calanoidae,
Cyclopoidae, Harpacticoida (Copepoda), Diplostraca (Cladocera),
Podocopida (Ostracoda), Amphipoda, Isopoda, Thermosbaenacea,
Bathynellacea, Decapoda and some water environment indicators. rescue
(T0, pH, DO, NH4+, NO3-, PO43-).
- Scope of study: Study on species composition, distribution,
species composition and the number (density) of freshwater crustacean in
the karstic waters of Phong Nha - Ke Bang National Park
2.2. Study sites
The study in an area of waters of Phong Nha-Ke Bang National Park,
include: stream, reservoirs on the ground and underground water in cave.
Location of survey sites.
A total of 22 watersheds in the Phong Nha-Ke Bang were collected.
In particular, there are many water bodies surveyed in many places, Son
River (3 sites), Chay River (3 sites), Khe Rinh (1 sites), Phu Nhieu (1
sites) Tan Hoa (1 sites), Cha noi (1 sites), Yen Hop (1 sites), Khe van(1
sites), Khe Dat (1 sites) Thien Duong (1 sites), Rao Con (1 sites) Phong
Nha cave (4 sites), Son Doong cave (4 sites), Thien Duong cave (3 sites),
Dark cave (2 sites), E cave (4 sites), 35 Cave (1 sites), Va Cave (2 sites),
Tu Lan cave (3 sites) and Yen Hop cave (1 sites).
2.3. The study period
- 4 year: From 2013 to 2017

- Crustacean sample were inherited from the two surveys in 8/ 2011
and 4/2013.
- During the implementation period, the thesis continues to survey
and expand the study sites with 5 study tours in April 2014, August 2014,
September 2014, April 2015 and August 2015 with the support of Young


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Independent Subject, VAST Code DLT.02_14-15 sponsored by the
Academy of Science and Technology.
- Sample collection: 89 visits / 22 places
- Number of specimens collected: about 1,100 specimens
2.4. Research Methodology
2.4.1. Research field
The planktonic crustaceans were collected at the surface level (0 –
5m) by using a 100-150 µm mesh-sized plankton net.
Collection of benthic crustacean was done by using a triangular
bottom trawl, size 30 cm x 30 cm x 30 cm, mesh size 100 μm. In places of
great depth, the benthic crustacean was collected by Petersen size 25cm x
25cm. Methods of collecting crustacean samples in cave as instructed by
Camacho et al. (1992).
2.4.2. Research in the laboratory:
a. Sample processing and analysis freshwater Crustacea
Qualitative analysis: Classification of crustal groups was done using
morphological comparison method with the support of optical devices,
descriptive drawing and imaging. Critical morphological details in
crustacean classifications were tracked following the process of Dang
Ngoc Thanh, Ho Thanh Hai 2012, Kotov et al., 2009, Karanovic, 2012
and Bozzola & Russell (1999). Sort of taxa was done following Martin
and Davis (2001) classification system.

Determining density of the subjects follows routine methods, using
the Bogorov counting chamber of 10 ml and calculating the number of
individuals/m3.
b. Techniques for collecting, preserving and analyzing physical and
chemical water environment
Field sampling and sampling techniques, sample preservation, sample
transport, sampling follow the guidelines of Vietnamese Standards QCVN
6663-1: 2011. Comparison, price of water quality according to QCVN 09:
2015 / BTNMT; QCVN 08: 2015 / BTNMT.
c. Calculation of biological indicators
Assessment of community species diversity and water quality
assessment through the Margalef (d), Shannon-Weiner diversity
index(H’), Pearson (r).
Data processing techniques: Biological statistics were processed by
Excel 2010, PAST v.2.17.


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Chapter III. RESEARCH RESULTS
3.1. The species composition of freshwater crustacean in the study
area
Reseach results on species composition show that 93 species in
different the regional waters of karsts of 10 orders, 27 families and 61
genus have been recorded. Cyclopoidae has 27 species, 29% of total
species, Diplostraca has 26 species, (28%), Decapoda (16 species, 17,2%),
Harpacticoida (9 species, 9% Calanoida (8 species accounting for 8.6%),
Podocopida (3 species accounting for 3,2%). The other four include
Thermosbaenacea, Bathynellacea, Amphipoda, Isopoda each with only 1
species accounting for 1,1%.
3.1.1. Freshwater Copepoda

Copepods have 44 species (47,3% of total species) belonging to 24
genus, 8 families and 3 oders of Calanoida, Cyclopoida, Harpacticoida. Of
these, 9 taxa have only been identified at the genus, including:
Mongolodiaptomus sp., Acanthocyclops sp., Bryocyclops sp., Eucyclops
sp., Halicyclops sp., Graeteriella sp., Rybocyclops sp., Tropocyclops sp.
(family Cyclopidae) and Nitocrella sp. (Ameiridae family). Six species:
Graeteriella
longifurcata,
Nannodiaptomphiliennisis,
N.
haii,
Neodiaptomus curvispinosus, Halicyclops songsonensis, and Mesocyclops
sondoongensis were the first described species in Vietnam and are
currently only found in the karsts of the Phong Nha-Ke Bang National
Park, these are endemic to Vietnam.
For the first time, the four freshwater genus distributed in Vietnam
are: Acanthocyclops, Bryocyclops, Rybocyclops, Nitocrella. The
Cyclopidae family had the largest number of species with 25 species
(26,9% of total crustaceans), the Diaptomidae (6 species, 6,5%),
Ameiridae and Canthocamptidae has 4 species account for 4,3%,
Pseudodiaptomidae family has 2 species (2,2%), the remaining family
each has only one species.
3.1.2. Freshwater Cladocera
The reseach results on species identifying show that 26 species (28%
of total species) belonging to a Diplostraca oder of 7 families and 22
genus have been identified. At families, the Chydoridae have the largest
species with 13 species (14% ), The Daphniidae and Sidiidae (3 species,
3,2%), Bosminidae, Macrothricidae and Moinidae each have two species
(2,1%), the Ilyocryptidae have 1 species (1,1%). Cladocera represents a
high diversity with the rate of species (26)/genus (22) reaching 1,18 and

species (26)/families (7) reached 3,71. Based on the results of the study, a


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new species was identified to genus as Brancelia sp. it is distributed in the
cave.
3.1.3. Freshwater Ostracoda
Three species Ostracoda (3,2% of total species); these include:
Pseudostrandesia calapanensis (family Cyprididae), Meridiescandona
lucerna (Family Candonidae) and Notodromas sp. (Notodromadidae
family). Among them are Meridiescandona lucerna and Notodromas sp.,
the first recorded in the cave of Vietnam. Two species of
Meridiescandona genus and Notodromas genus are found only in the
cave, while P. albacanensis is widespread, often in mountainous waters.
3.1.4. Bathynellacea và Themosbaenacea
The results of the study have identified two crustacean species that
are only classified genus as: Theosbaena sp belonging to the
Thermosbaenacea family and the Siambathynella sp species belonging to
the Bathynellacea family, which are typical cave dwellings species. These
are the first records for the Vietnamese aquatic system.
3.1.5. Amphipoda và Isopoda
One species of Amphipoda belongs to the Bogidiellidae family and
one species of Isopoda belong to the Corallanidae family have been
recorded. At present, Vietnam has only recorded 8 species of Amphipods
and 2 species of Isopoda.
3.1.6. Decapoda
According to the analysis, there were 16 species of Decapoda (17,2%
of total species) of 8 genus, 5 families, including 10 species of shrimp
(10.7%), 6 species of crabs (6,5%). The most abundant species were the
Palaemonidae with seven species, the Atyidae and the Potamidae each

with three species, the two species of Parathelphusidae and the Varunidae
with one species. Based on the results, 11 species have been added to the
Decapoda crustacean system in the karst areas of Quang Binh.
Of the 16 species of Decapoda identified in the study area, seven
species (46.6% of total species) are now endemic to Vietnam, including:
Caridina subnilotica, C.auticaudata, Macrobrachium phongnhaense,
Indochinamon phongnha, Nemoron nomas, Villopotamon sp.,
Somanniathelphusa pax
A new species of shrimp (Macrobrachium phongnhaense) was first
record and described during the study. So far, this species has only been
found in caves in Phong Nha-Ke Bang National Park, as: Va Cave, 35
Cave, Tu Lan Cave and Son Doong Cave. A species of Varuna litterata


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was recorded at the survey sites of the Son River. The study also recorded
a species of Villopotamon sp. The species name is also likely to be new to
science.
3.2. Distribution characteristics of species composition and a
number species
3.2.1. Distribution by types of water bodies.
There were 49 species in underground water of the cave (52,7% of
total species), 55 species in the stream (59% of total species), 52 species
in the river (55,9% of total species) and 41 species in reservoirs (44,1% of
total species).
3.2.1.1. The ground water in cave
Based on the survey results, we have collected 49 species Crustacea,
accounting for 52,7% of the total number of 10 Order, 19 families and 37
genus. Of these, the most abundant is the Cyclopoida (Copepoda), with 20
species (21,5% of total species and 40,8% of total species in the cave),

Harpacticoida (Copepoda) has 8 species, Diplostraca (Cladocera) has 7
species, Calanoida has 5 species, Ostracoda has 3 species, Decapoda has 2
species, Thermosbaenacea, Bathynellacea, Amphipoda and Isopoda each
have only one species.
For Ecologically, crustaceans in the cave could be grouped into two
groups: the typical cave species group (Stygobites) and the unidentified
cave species group(stygophiles)
Typical cave species (stygobites): These include species that are only
found in cave basins, usually deep in the cave. There are 24 species of
crustaceans (49% of cave species and 25.8% of total species), 21 genus,
12 families and 9 oder. In particular, the Cyclopoida (Copepoda) has the
largest number of species with 10 species, the Calanoida and the
Ostracoda each have three species, the Harpacticoida (Copepoda), the
Decapoda has two species, the remaining one each. Isopoda does not
recognize any species in this group.
Species of the cave are unofficial (stygophiles): typical of this group
is distributed both in caves and in other terrestrial waters in topography
karst (streams, rivers, lakes). There are 25 species (51% of cave species
and 26,9% of total species) in 21 genus, 11 families and 5 oder. In
particular, the Cyclopoida (Copepoda) has the largest number of species
with 10 species, the Diplostraca (Cladocera) and the Harpacticoida
(Copepoda) each have 6 species, the Calanoida has two species and the
Isopoda has one species. The Podocopida, Thermosbaenacea,
Bathynellacea, Amphipoda and Decapoda have not recorded any species.


13
Group of caves with typical cave species predominate: There are 9
species of stygobites in the Va Cave, accounting for 100% of the
stygobites species and no stygophiles species; Thien Duong has 14

stygobites species, accounting for 87,5% (2 species of stygophiles,
accounting for 13,5%); Dark caves have 11 stygobites species, accounting
for 78,6% (3 species of stygophiles, accounting for 21,4%); Cave 35 has
15 stygobites species, accounting for 78,9% (4 species of stygophiles,
accounting for 21,1%); Son Doong cave has 15 stygobites species,
accounting for 68,2% (7 species of stygophiles, accounting for 31,8%).
Group of caves with dominant atypical species composition: Yen Hop
cave, Tu Lan cave, Phong Nha và hang E cave. Phong Nha cave has 20
species of stygophiles, accounting for 95,2% of species (only 1 species of
stygobites, accounting for 4,7%); There are 14 species of stygophiles,
accounting for 93,3% (1 species of stygobites, accounting for 7,7%); Tu
Lan cave with 11 species of stygophiles, accounting for 78,6% (3 species
of stygobites, accounting for 21,4%) and Yen Hop caves have 8 species of
stygophiles, accounting for 61,5% ( 5 species of stygobites, 38,5%).
3.2.1.2. Water bodies on the ground
69 species of crustaceans (74,2% of total species) in 46 genera, 21
families and 6 orders (Diplostraca, Calanoida, Cyclopoida, Harpacticoida,
Isopoda and Decapoda) were recoded. The other four are Podocopida,
Thermosbaenacea, Bathynellacea, Amphipoda not recorded species. Of
these, the Diplostraca (Cladocera) has 25 species (26,9% of the total
species and 36,2% of the total on the ground), Cyclopoidae (Copepoda)
has 17 species, Decapoda has 14 species, Harpacticoida (Copepoda) has 7
species, Calanoida has 5 species, Isopoda has 1 species.
Ecologically, it is possible to distinguish crustacean species in
terrestrial waters as two major groups: the typical grouping of terrestrial
surface water bodies (epigean species) (species can only be found in
groundwater (rivers, streams, lakes) not found in cave basins) and
unidentified cave species. (stygophiles)
Species of the cave are unofficial (stygophiles): they are distributed in
both the surface waters and cave (described above 3.2.1.1).

Typical species for on the ground (epigean species): There are 44
species belonging to 35 genera, 18 families and 5 oder (Diplostraca,
Calanoida, Cyclopoida, Harpacticoida and Decapoda), accounting for
63,7% of species on the ground and 47,3% of total species. The
Podocopidae, Thermosbaenacea, Bathynellacea, Amphipoda and Isopoda
have not recorded any species.


14
Distribution according to types of terrestrial waters characteristic of
the study area include rivers, streams and reservoirs.
Crustacean species were recorded in streams with 55 species (59,1%
of total species), rivers with 52 species (55,9%) and lakes with 41 species
(44,1%). The Diplostraces have 22 species in rivers and streams, 19
species in reservoirs. Cyclopoids have 13 species in streams, 12 species in
rivers and 8 species in reservoirs; The Decapoda has 7 river species, 13
species in the stream and 6 species in the reservoir. The Harpacticoida
have 6 species in the river, 5 species in the stream and reservoir;
Calanoida have 4 species in the river 2 species in the stream and 3 species
in the reservoir, the Isopoda have only one species in the river.
3.2.2. Distribution between planktonic crustaceans and benthic
crustaceans.
The research has identified 65 species of planktonic crustaceans
(accounting for 69,9% of total species) and 39 species of benthic
crustaceans (accounting for 41,9% of total species).
Crustaceans live in the upper layer (planktonic crustaceans):
Cycopoida have 27 species (29% of total species), Diplostraca have 25
species (26,9%), Calanoida have 8 species (8,6%), Harpacticoida and
Podocopia have only 1 to 4 species. The Thermosbaenacea,
Bathynellacea, Amphipoda, Isopoda and Decapoda have not recorded

species.
Crustaceans living in the bottom layer (benthic crustacea): The
Species composition is dominant in this group belongs to the Decapoda
with 16 species (17,2% of total species), Harpacticoida have 9 species
(9,6%), Cylopoida have 6 species (6,4%), Podocopia has 3 species (3,2%),
the other four oder (Thermosbaenacea, Bathynellacea, Amphipoda and
Isopoda) each have only 1 species (1%). For the Diplostraca with the
dominant species at the surface level (25 species), however, no species
was recorded at the bottom.
3.2.3. Seasonal distribution
There are 80 species of crustaceans in the dry season (86,0% of the
total species) and 70 species in the rainy season (75,2% of the total
species). In both seasons, there are representatives of freshwater
crustacean in the karst. The two most abundant oder are the Diplostraca
(Cladocera) (21 species in dry season and 20 species in rainy season) and
Cyclopoida (Copepoda) (22 species in dry season and 17 species in rainy
season); The Decapoda with 15 species in dry season and 13 species in


15
rainy season. At least one species of Isopoda is present in the dry season
and no species appear in the rainy season.
3.3. Distribution of density of the Crustacea
3.3.1. Crustaceans living in the upper (Planktonic Crustacea)
The density of Planktonic crustaceans from 22 to 2131 individuals
/m3, the average values ranged from 31,5 to 1440 individuals/m3, with the
appearance of the Diplostraca (Cladocera), Calanoidae, Cyclopoida,
Harpacticoida (Copeopoda), and Podocopida (Ostracoda), in which
Cyclopoida and Diplostracia dominate. Surface water bodies and cave
basins also show differences in density and structure of Planktonic

crustacean species.
For the underground water bodie in the cave: The average density
from 46,3 to 152,0 individuals /m3, with the density advantage in most of
the survey sites belonged to the Cyclopoida (39,5 – 79,4%) Total density
of Diplostraces is lower (from 8,0 to 38,2%). The highest average density
at Va cave was 152,0 ± 35 individuals /m3 and lowest in Phong Nha cave
with 46,3 ± 8 individuals /m3.
For watershed on the ground: the average Planktonic crustacean
density ranges from 74,7 to 1150,2 individuals/m3 with the density of
species in the Diplostraca and Cyclopoida, from 25,2 – 65,8% of total
densities in Diplostraca and 23,9 – 66,8% in Cyclopoida
Density of planktonic crustacean groups in reservoirs: Dong Suon
lake averaged from 380,7 to 879,0 individuals/m3 and Khe Ngang lake
averages from 962,3 to 1440,0 individuals/m3. In the species composition,
the predominant density of species groups is evident. The Cyclopoidae,
Diplostraca and Calanoida grow in numbers in standing or slow-moving
water.
For streams, the average planktonic crustaceans ranged from 74,7 to
154,0 individuals/m3. In the composition of the species composition, the
Diplostraca and the Cyclopoida have advantages.
For the Son and Chay River basins, the variability ranged from 175,2
to 327,3 individuals/m3. In terms of species composition, the Diplostraces
and Cyclopoids still dominate (accounting for 25,2-66,8% of the
population). These are species adapted to the flowing water environment.
Variation of plaktonic crustacean densities in season: For 7 surveys
(3 rainy season and 4 rainy season), the variability of planktonic
crustaceans in the water bodies was clearly shown: almost the dry season


16

density was higher than with the rainy season depending on the different
water surface conditions
For River, tream basins on the ground: The density of planktonic
crustaceans in the dry season was higher than that of the rainy season with
average density of 89,0 - 371,1 individuals /m3 in the dry season and (from
64,5 – 233,7 individuals / m3 in the rainy season).
For underground water basins in cave: In underground streams with
continuous flow from surface water bodies (E cave, Tu Lan cave): in the
dry season, the density from 133,0 to 145,5 individuals/m3 is higher than
that in the dry season. With the rainy season, the average is from 81,8 to
90,0 individuals/m3
In the underground streams from the cave (Phong Nha cave, Dark
cave, Son Doong cave, Thien Duong cave), the difference between the
two seasons is negligible with the dry season (from 51,0 to 68,8
individuals/ m3) and rainy season (from 43,0 to 64,3 individuals /m3).
In the small pond or lake in the cave (35 cave, Yen Hop cave and Va
cave), the planktonic crustaceans in the rainy season (from 52,0 to 196,0
individuals/m3) higher than that in the dry season (from 42,0 to 130,0
individuals /m3).
3.3.2. The Benthic crustacean
Based on the results of the reseach, the density of benthic crustacean
from 3 to 70 individuals /m2 in water bodies, with an average value of 20,2
- 40,9 individuals /m2. In which Cyclopoida, Harpacticoida (Copeopoda)
completely dominate (accounting for 31,5 - 100,0% density). Through
analysis, only three oder of Cyclopoida, Harpacticoida (Copeopoda),
Podocopida (Ostracoda) are present in the samples both in the upper and
lower layers.
The density of benthic crustaceans was 29,1 ± 4,9 individuals /m2 in
suface water bodies and 32,9 ± 5,7 individuals /m2 in cave basins.
Composition of benthic crustacean in terrestrial surface water bodies

consists of 3 orders: Cyclopoida, Harpacticoida and Decapoda. However,
benthic crustacean in the basin of the cave have the appearance of species
belonging to the Podocopidae, Thermosbaenacea, Amphipoda, which are
typical species in the cave. In water bodie on the ground, the diverticulata
was 28,9 ± 6,2 individuals / m2, the streams were 27,5 ± 4,9
individuals/m2 and the reservoir was 31,7 ± 2,9 individuals/m2. The
variability of benthic crustaceans tends to increase with the flow direction
in the water bodies.


17
The seasonal variation benthic crustacea of density: The seasonal
variation in the terrestrial waters is more evident than groundwater bodies
in cave.
The groundwater bodies in cave, seasonal fluctuations are not large,
In Va cave, 35 cave, Heaven cave in rainy season is higher density than
dry season, however, the difference is not large. E cave, water bodie rive
stream in the cave with frequent flowing water However, cave E is a creek
in the cave with frequent flow of water and fluctuations in the flow
between the rainy season and the dry season, therefore the dry season
density (26,9 ± 11,8 individuals/m2) was higher than the rainy season
(15,0 ± 2 individuals/m2). For water bodies such as rivers and streams on
the ground, the density of benthic crustaceans in dry season (31,3 ± 8
individuals/ m2) was higher than that of rainy season (25,5 ± 6 individuals
/m2). The variation in density in the reservoir also had the difference in
average dry season density of 35,9 ± 5,8 individuals/m2 higher than the
rainy season with a density of 29,6 ± 3,9 individuals /m2
3.4. Biodiversity of freshwater crustaceans
3.4.1. The Planktonic Crustacean.
3.4.1.1. The Margalef index (d)

The Margalef index (d) of Planktonic crustacea ranges from 0,80 to
2,51. In particular, the lowest in the streams (1,47 ± 0,21), the cave basins
(1,68 ± 0,25); in the reservoir (1,83 ± 0,11) and highest in the river (1,91 ±
0,21). The Margalef index ranges from 0,80 to 2,29 for the cave. Some
caves with high abundance index such as Tu Lan cave (d average 1,94 ±
0,10), Dark cave (1,84 ± 0,08), Phong Nha cave (1,83 ± 0,15 ) and E cave
(1,77 ± 0,24) because they have regular water exchange with open water
bodies. The remaining water bodies have lower margalef such as cave Va
(1,21 ± 0,16), Thien Duong cave (1,33 ± 0,26) and Yen Hop cave (1,64 ±
0,03) As these deep in the cave, the level of connection of water sources
with water bodies on the ground is limited
For water bodies on the ground: The species richness index in the
two reservoirs was 1,83 ± 0,11, the difference in abundance of freshwater
crustacean was not significant, d index from 1,39 to 2,19. For the streams,
the d index was low (1,47 ± 0,21) and fluctuated considerably, from 1,12
to 1,95. The streams are located in the core zone of Phong Nha - Ke Bang
National Park, such as Thien Duong (1,72 ± 0,09), Khe Dat (1,69 ± 0,21),
Rao Con (1,45 ± 0,06) higher the streams in the buffer zone, Phu Nhieu
stream (1,30 ± 0,23), Cha Noi stream (1,29 ± 0,12), Yen Hop stream (1,39


18
± 0,06) and other streams near the residential area, Khe Rinh (1,46 ±
0,12), Tan Hoa stream (1,25 ± 0,07).
Variable margalef index of freshwater crustaceans in seasonal
In river, stream on the ground, richness index of Planktonic
crustacean in dry season (average 2,04 ± 0,11 in rivers and 1,80 ± 0,19 in
streams ) was higher than the rainy season (1,54 ± 0,14 in the river and
1,38 ± 0,15 in the stream). For underground water in cave, the rainy
season (1,69 ± 0,22) was higher than the dry season (1,65 ± 0,24). In

reservoirs, the difference richness index between the two seasons was
similar, with an average of 1,83 ± 0,07 in the dry season and 1,84 ± 0,09
in the rainy season.
3.4.1.2. Shannon-Weiner diversity index(H’)
The diversity index of the freshwater Planktonic crustaceans ranges
from 1.18 to 2.80. In particular, the lowest in the streams (1,63 ± 0,24), the
cave (1,95 ± 0,01) and the highest in the lake (2,09 ± 0,12) and in the river
(2,10 ± 0,25). Aquifers in the cave, the species diversity index H' from 1,32
to 2,31, the average value between the water areas ranged from 1,79 to 2,06.
Results of variation in freshwater crustacean diversity indexes in
seasonal watersheds: In river basins, stream on the ground, the abundance
of crustaceans in the rainy season (2,04 ± 0,22 in the river and 1,54 ± 0,16
in the stream) were lower than those in the dry season (2,21 ± 0,13 in the
river and 1,71 ± 0,16 in the stream) (with p> 0.05).
For underground water in the cave, the difference in seasonal species
diversity is negligible: H' average was 1,96 in the rainy season, higher in
the dry season (1,92 ± 0,09 ). In the seasonal reservoir of the H 'diversity
index in the rainy season (2,11 ± 0,09) tended to be higher than in the dry
season (2,04 ± 0,10)
3.4.2. The benthic crustacean group
3.4.2.1. Margalef index (d)
The richness index of freshwater benthic crustaceans ranged from
0,54 to 2,07. In particular, the highest abundance was found in the river
(1,52 ± 0,22), reservoir (1,27 ± 0,14), cave basins (1,11 ± 0,16) ) and
streams (1,13 ± 0,22). Seasonal survey: In rivers, the rainy season (1,67 ±
0,22) was higher than the dry season (0,41 ± 0,08). At the same time, the
difference in species richness between dry and rainy seasons is not
significant for other: in streams (1,07 ± 0,21 in dry season and 1,10 ± 0,11
in rainy season); lakes (1,12 ± 0,10 in the dry season and 1,32 ± 0,05 in

19
rainy season) and in the basin of the cave (1,12 ± 0,19 in the dry season
and 1,07 ± 0,17 in rainy season). (with p> 0.05)
3.4.2.2. Shannon-Weiner diversity index(H’)
Based on the results, the species diversity index (H ') ranged from
0,76 to 2,27. The survey sites in the streams with the lowest diversity
index H ', the average was 1,31 ± 0,13, the basin in the cave (1,40 ± 0,19),
the reservoir water (1,42 ± 0,11), Song Son and Chay River are the
highest H', Son River (1,81 ± 0,24) and Chay River (1.57 ± 0.23).
Seasonal survey: rainy season is usually higher than dry season,
average 1,79 ± 0,25 in rainy season and 1,62 ± 0,10 in dry season. Similar
results for each type of water body are in lakes: (1,45 ± 0,09 in rainy
season and 1,37 ± 0,07 in dry season); (1,30 ± 0,08 and 1,27 ± 0,06) in the
stream and (1,41 ± 0,06 and 1,33 ± 0,15) in the basin of the cave. These
indicators show the relative stability of the habitat and aquatic
communities at the bottom of the water bodies.
3.5. Correlation between freshwater crustaceans and
environmental factors.
3.5.1. Water quality in the karst areas of Quang Binh Province
Based on the analysis of 9 indicators of physical and chemical factors
water environment in Phong Nha - Ke Bang karstic waters, we can
comment on the current state of the water environment.
Compared with the standard of surface water bodies environment
used for daily life and protection of aquatic life; most of the surveyed
indicators are within the allowable limits (QCVN 08: 2015, QCVN 09:
2015).
There are some differences in the physical and chemical indicators
between surface water bodies on the ground and cave basins. The
difference in this water environment is mainly due to the hydrological

regime, the basin structure, the water body type, especially the sunlight
mode (underground water in caves without sunlight). This shows that
although there are certain connections between the inner and outer rivers
in the rainy season, the habitat between the basin in the cave and the outer
surface is completely different.
Nowadays, with the development of tourism and other activities of
people here, more or less impact on the natural ecological environment in
the Phong Nha-Ke Bang National Park, so there must be solutions. To
improve the people's consciousness in order to protect and maintain the
current status of the water environment in these water basins, which is


20
also the basis for the sustainable development, harmony between
environmental protection and economic development.
3.5.2. Correlation between environmental factors and biological
parameters of crustaceans.
For surface water bodies such as rivers, streams and lakes. Physical
factors such as temperature and light have a very weak correlation with
the species index, density and diversity index. Indicators such as pH,
Stiffness and salinity are weakly correlated with the species, density of the
freshwater crutacean. The DO and NO3-content indexes have a mean
correlation (0,12-0,35) and ammonium content (0,35-0,56), phosphorus
(0,35-0,61) have a tight correlation. Nutritional factors from ammonium
salts (NO3-) and phosphates (PO43- ) have variable variability associated
with changes in species index, density and diversity index. As the nutrient
content increases, the number of species, density and diversity tend to
increase. This result reflects the characteristics, in accordance with the
results of the analysis of physical and chemical factors in the watershed
here: poor nutrition.

For groundwater bodies in caves, water environment factors such as
temperature, hardness, and pH have a weak correlation with species
indexes, density and diversity indexes. The chemical indices such as DO,
NH4 +, NO3-, PO43- in groundwater bodies are positively correlated and
fluctuate relatively closely with species variation (coefficient of
correlation r from 0,58 – 0,73). Crustal density is strongly correlated with
NO3- (0,81); PO43-, NH4+, DO have average correlation. For the Margalef
index (d) and the diversity index (H ') the correlation coefficient for water
environment factors such as (DO, NH4+, NO3-, PO43-) ranged from
medium to low (0,32-0,59).
3.6. Solutions for conservation and sustainable use of freshwater
crustacean resources in the study area
3.6.1. Main threats to the aquatic ecosystem and crustacean
communities in Phong Nha - Ke Bang.
At present, the decline of natural resources in general is taking place
in many localities in the country. With the impact of natural disasters and
other human-induced activities, crustacean resources in Phong Nha-Ke
Bang National Park are also seriously threatened, such as the effects of
weather, due to climate change; Deforestation of watersheds,
overexploitation of fishery resources, especially tourism activities have
been strongly developed in Phong Nha - Ke Bang.


21
3.6.2. Suggested solutions for conservation of ecosystem biodiversity
and crustacean communities in caves in Phong Nha - Ke Bang.
Based on the results of the study and field surveys, five groups of
solutions proposed to conserve and develop the biodiversity in general and
the crustacean group in particular include: sustainable tourism
development planning, Raise awareness on biodiversity conservation

education; Build awareness of environmental protection for local
communities and visitors; Develop scientific research projects and
biodiversity monitoring; Control of invasive alien species.
CONCLUSION AND RECOMMENDATION
I. CONCLUSION
1. Based on the results, 93 crustacean species have been identified in
the karstic areas of Phong Nha-Ke Bang National Park, belonging to 61
genera, 27 families and 10 oders. Among them, one species (Halicyclops
songsonensis Tran, Le & Ho) has been new record to science.
For the first time, two oder of fresh water crustacean
(Thermosbaenacea and Bathynellacea), 5 families (Notodromadidae,
Candonidae, Halosbaenidae, Parabathynellidae, Bogidiellidae), 11 genus
(Acanthocyclops, Nitocrella, Brancelia, Bryocyclops, Graeteriella,
Rybocyclops,
Notodromas,
Meridiescandona,
Theosbaena,
Siambathynella, Bogidiella). In addition, 14 species and unidentified
species have many characteristics that differ from species currently
known. These may be new to science, but additional specimens and
information are needed to ensure accuracy when describing species.
2. Identification of species distribution and composition of species by
water type, water layer and season. Of which, streams have the highest
number of species (55 species, accounting for 59,1% of total species),
rivers (52 species, accounting for 55.9%), underground water in caves (49
species, accounting for 53,7% % and reservoir (41 species, accounting for
44,1%). Surface of the water body has more species than the bottom (65
and 39 species respectively); Dry season recorded higher species than
rainy season (80 species compared to 70 species).
According to the distribution characteristics of freshwater

crustaceans, the stygobites (24 species, accounting for 25,8%), stygophiles
(25 species, accounting for 26,9%) and epigean species (44 species,
accounting for 47,3%).
3. Crustacean densities in the karstic areas of Phong Nha-Ke Bang
National Park ranged from 3 to 70 individuals/m2 in the benthic
crustacean and in the plankthic crustacean from 22 to 2.131


22
individuals/m3. Characteristics of freshwater crustaceans are described by
the type of surface water bodies (rivers, streams, reservoirs) and
underground bodies in caves (underground rivers, puddles, underground
siphon pools). In surface water bodies, the reservoirs have the highest
density of crustaceans (from 380,7 to 1440 individuals/m3). For cave
basins, the highest density of siphon reservoirs and the lowest seasonal
lowland floods were from 46,3 to 63,3 individuals/m3).
4. The Margalef diversity index (d) and the species diversity index
(H') in crustacean waters of Phong Nha - Ke Bang National Park are
average, with the plankthic crustacean ranging from 0,80 to 2,51 (d index)
and 1,18 to 2,80 (H ') and for the benthic crustacean ranged from 0,54 to
2,07 (d) and 0.76 to 2,27 (H'). The results show that the abundance index
and diversity index in the underground water is equal to or higher than
that of the stream.
5. The water environment in the karst areas of Phong Nha-Ke Bang
National Park includes both surface water and underground water in the
cave are good condition; Physical and chemical indicators are within the
permitted limits as compared to Vietnamese standards
In most of the karstic areas of Phong Nha-Ke Bang National Park, the
characteristics of freshwater crustaceans (number of species, density, d,
H') are weakly correlated with physical indices Temperature, pH,

stiffness, while they are positively correlated, varies from medium to tight
with chemical indices such as DO, ammonium salt, nitrate, phosphate in
water.
6. It has been determined that the rapid development of tourism in
Phong Nha - Ke Bang National Park is a major factor affecting the
ecosystem of the cave and the crustacean. Based on that, five solutions
have been proposed to preserve cave ecosystem and endemic crustacean
species in Phong Nha - Ke Bang National Park.
II. RECOMMENDATION
1. In the coming time, it is necessary to study and collecte more
specimens, for unidentified crustaceans in the cave (14 species) and
especially for the 5 species with description. In addition, studies on other
aquatic organisms (molluscs, fish, etc.) should be extended to serve the
management of biodiversity conservation in the cave basin. .
2. Based on the research results of this thesis, light is an
environmental factor that determines the ecological characteristics of the
crustaceans living in caves only. Therefore, it is necessary to orient the
biological experiment to determine the intensity of light affecting the


23
behavior and habitat of this ecological group.The results of the study will
be the basis for the identification of environmental indicator organisms in
the cave aquifer.
THE NEW CONTRIBUTION OF THE THESIS
- Based on the results of this thesis, we have provided the most
complete data to date on the composition of freshwater crustacean in
Phong Nha-Ke Bang National Park, including 93 species, 61 genus, 27
families in 10 oder
- One species (Halicyclops songsonensis Tran, Le & Ho) has been

newly recorded to science; provide data and specimens to describe and
announce three new species for science: Mesocyclops sondoongensis,
Nannodiaptomus haii and Macrobrachium phongnhaense. The results of
the study were supplemented with two oder of freshwater crustacean
(Thermosbaenacea and Bathynellacea), five families (Notodromadidae,
Candonidae, Halosbaenidae, Parabathynellidae, Bogidiellidae) and 11
species
(Acanthocyclops,
Nitocrella,
Brancelia,
Bryocyclops,
Graeteriella, Rybocyclops, Notodromas, Meridiescandona, Theosbaena,
Siambathynella, Bogidiella). Most of these taxa are official life
representatives in cave basins.
- Distribution characteristics of species composition and density of
freshwater crustacean communities in Phong Nha-Ke Bang karstic waters
were analyzed and evaluated in detail by type of water bodies (49 species
in basins, 55 species in streams, 52 species in rivers, 41 species in
reservoirs), (65 species Planktonic crustacea and 39 species benthic
crustacean) and seasonal climate (80 species in the dry season and 70
species in the rainy season). Classification of species groups based on
ecological characteristics, distribution according to specific types of
watersheds in the study area (24 the stygobites species, 25 stygophiles
species and 44 epigean species ). These are new data of scientific and
practical value in the research and management of biodiversity and
conservation of limestone species in Phong Nha - Ke Bang.
- Determining the species diversity of freshwater crustacean species
in Phong Nha-Ke Bang karstic areas, including rivers, streams, reservoirs
and cave basins. The results show that the abundance index and diversity
index in the groundwater bodies in caves is equal to or higher than that of

the stream.