1 MINISTRY OF EDUCATION AND TRAINING HA NOI NATIONAL UNIVERSITY OF EDUCATION LAI THU HIEN THE STRUCTURE AND ROLE OF ORIBATID MITE COMMUNITY (ACARI: ORIBATIDA) IN THE RED RIVER DELTA, NORTH OF VIETNAM Major: Zoology Code: 9420103 SUMMARY OF PHD THESIS IN BIOLOGY Ha Noi – 2019 This thesis has been completed at Hanoi National University of Education Scientific Advisor: Prof D.Sc.Vu Quang Manh Referee 1: Assoc Prof., Ph.D Nguyen Van Vinh VNU University of Science Referee 2: Assoc Prof., Ph.D Nguyen Thi Phuong Lien Institute of Ecology and Biological resources Referee 3: Assoc Prof., Ph.D Vu Van Lien Vietnam national museum of nature The thesis will be reported at the school assessment council at Ha Noi National university of education on hour .date month year The thesis can be found at: National Library of Vietnam Library of Hanoi National University of Education INTRODUCTION Scientific basis and importance of research issues In the group of land animals, oribatida is always dominant, about more than 90% of the total number of Acari Oribatida plays many important roles, they participate in the process of soil formation, actively participate in decomposing organic compounds Base on the ability of horizontal and vertical migration in the soil, oribatida is also a vector that carries and spreads many bacteria, fungi and parasitic helminthes Because of such important position and role in the soil ecosystem, oribatida became an early research object of scientists Facing the increase of environmental pollution and climate change, the research and application of the indicative role of oribatida in exploiting and developing the natural environment is more and more interested in research In Vietnam, the various of climate, topography, soil type and vegetation cover of nature have impacted on the formation of oribatida mite fauna according to regional characteristics Therefore, researching about oribatida in the local areas to supplement the data for the Vietnamese oribatida mite fauna is still necessary The Red River Delta is a large area, accounting for about 7.1% of the country There have been some studies on the community of land animals in general and the oribatida mite community in particular, but the researches are incomplete Base on the scientific meaning, practical requirements and the ability to perform, we propose research topics: « The structure and roles of Oribatid mite community (Acari: Oribatida) in the Red River Delta, North of Vietnam » Objectives of the study Study on species composition and variation of oribatida mite (Acari: Oribatida) community in the Red river Delta, related to natural and human factors: type of soil, type of habitat and fertilizer; make scientific basis for sustainable management of agricultural ecology in Vietnam Research content  Investigate the diversity of species composition of oribatida mite community in the soil ecosystem of the Red River Delta  Analyse the taxonomic structure of oribatida mite community in the study area and their relevance to some related areas  Study the structure of oribatida mite community and their variation related to the type of habitat  Study the oribatida mite community structure and their variation related to soil type and fertilizer characteristics  Evaluate the role of oribatida mite community in the study area New contributions of the thesis The theis has produced a full list of known species of oribatida mite community in the Red River Delta, Northern Vietnam This list contains 283 species, belonging to 129 genera, 57 families (49 species have not been identified, in the form of "sp.") All of the recorded species are introduced to the distribution according to habitat types and soil types The list includes 106 species, belonging to 39 genera and 12 families recorded for the first time for the fauna of oribatida mite in the Red River Delta Among them, there are 64 species were first recorded for Vietnam Built the taxonomic structure of oribatida mite community in the Red river Oppiidae is the largerst family, accounting for 13.95% of the total number of genera and 12.72% of the total number of species in the study area Scheloribates and Protoribates are the two largest genera, corresponding to 10.60% and 7.42% of total species The Scheloribates laevigatus is the most common species in the study area The study has analyzed the variation of the oribatida community on species composition, individual density, uniformity and diversity according to habitat type and soil type The results showed the flexible and sensitive changes of oribatida mite community structure correspond to the change of living environment conditions From there, it can be proposed to survey oribatida mite community as a bioindicator, contributing to managing the sustainable development of soil ecosystems The layout of thesis The thesis consists of 147 pages, opening pages, 16 overview pages, 10 pages of time, location and research method, 91 pages of results and discussions, pages of conclusions The thesis has 17 tables and 20 pictures There are 23 reference pages with 57 Vietnamese documents, 144 English documents and 13 other foreign language documents CHAPTER 1: OVERVIEW 1.1 Overview of research on oribatida mite (Acari: Oribatida) in the world In the world, research on oribatida mite was started in the early nineteenth century Initial studies focused on classification and fauna So far, studies on the fauna have been increasingly expanded and developed in many different areas and ecological conditions The oribatida mite fauna of the world has been recorded 10,342 species and subspecies, belonging to 1,249 varieties and 163 families The studies on ecology and roles of oribatida mite have achieved many significant achievements The transformation of oribatida mite community structure has been studied on different habitats, different elevations, different climates with different temperature and humidity conditions… From then, it has pointed out the acumen of oribatida mite to the changes of environment, built a basis for the proposals that oribatida mitâtcn be used as a biological indicator for the living environment, making an important contribution to biodiversity conservation research 1.2 Study on oribatida mite (Acari: Oribatida) in Vietnam In Vietnam, the first study on oribatida mite was conducted in 1967 By 2013, the Vietnamese oribatida mite fauna has identified 320 species and subspecies, accounting for about 3.09% of the total number of known species in the world The number of studies in Vietnam is constantly increasing with the help of domestic and foreign experts The number of species is constantly increasing Especially, in the period from 2007 to 2015, the number of species of oribatida increased most rapidly with 355 species in years Most Studies are conducted in the North In the Central and the South, there are very few studies According to Vu Quang Manh's statistics in 2013, there are 50 oribatida research points in Vietnam, divided into regions There are only research sites are in the central and southern regions of Vietnam The oribatida mite community has been studied in different ecological conditions In terms of soil type, oribatida mite community has been studied on soil groups including: coastal saline soil, acidic alluvial soil, neutral alluvial soil, red brown pheralite soil, brown pheralite soil on rocky ground lime, reddish-brown soil on a ghostly stone background In terms of seasonal factors, oribatida mite community has been studied through seasons: spring, summer, autumn and winter In terms of human impact and forest degradation, the oribatida mite community has been studied on types of habitats: natural forest, human - disturbed forest, grassland and shrub land, grassland, cultivated land, agricultural land cultivated short-term crops 1.3 Study on oribatida mite (Acari: Oribatida) in the Red river Delta The first study on the group of microarthropda in the Red River Delta was conducted in 1982 From then to 2004, the number of studies was very little In the past 10 years, the number of studies has increased rapidly, but most of the studies have focused on conserve areas and national parks and have not focused on the region's agricultural ecosystem There are out of 11 provinces and cities in the Red River Delta region that have researched and out of national parks have studied on oribatida mite The studies were conducted on the impact factors: soil type, soil layer, level of humanity The fauna of oribatida mite in the Red River Delta has been recorded with 147 species, belonging to 86 genera, 40 families However, most of the studies only focused on assessing the diversity of species composition in the community 1.4 Overview of natural and social conditions of the study area 1.4.1 Geographical location and topography The Red River Delta is located around the lower Red River area in northern Vietnam, extending from latitude 21 ° 34 "N (Lap Thach district) to about 19 ° 5" N (Kim Son district), from 105 ° 17´E (Ba Vi district) to 107 ° 7´E (above Cat Ba island) The terrain is relatively flat with dense river systems The plain is gradually lower from the Northwest to the Southeast 1.4.2 Climate and hydrology The climate is subtropical, the winter is cold and dry, the structure of crops is diverse The annual average temperature is about 23 - 24°C The average annual rainfall is 1600 - 1800 mm 1.4.3 Soil and land According to the map of major groups and types of soil in Vietnam, alluvial soil is a major soil group that accounts for most of the area and distribute in most provinces in the region Saline soils are distributed in coastal areas of Hai Phong, Nam Dinh and Ninh Binh provinces The most acid sulphate soils are distributed in the coastal areas of Hai Phong There is also infertile gray soil on ancient alluvial soil, other types of soil and rocky mountain distributed in some areas in the region 1.4.4 Characteristics of agricultural cultivation and humanity society The Red River Delta is the most densely populated area in the country The population distribution involves many factors such as highly intensive agriculture with paddy rice cultivation that mainly requires a lot of labor Most of provinces in the Red River Delta have developed some cold-loving plants that bring high economic efficiency such as winter corn, potatoes, kohlrabi, cabbage, tomatoes and intercropping CHAPTER TIME, LOCATION AND RESEARCH METHOD 2.1 Time and place of study This study was conducted in 11 provinces and cities including: Vinh Phuc, Hanoi, Bac Ninh, Bac Giang, Ha Nam, Hung Yen, Hai Duong, Hai Phong, Thai Binh, Nam Dinh, Ninh Binh The time of collecting samples is mainly in the years from 2014 – 2016 In addition, the research sample is additionally collected in 2017 2.2 Methods of researching and treatment specimens 2.2.1 Method of collecting research samples The method of collecting soil samples and separating, analyzing and processing oribatida samples is used according to the specialized standard method which has been applied synchronously in Vietnam (Krivolutsky 1975, Schinner et al 1996 Vu Quang Manh 2003) Qualitative samples were collected from all provinces and cities in the study area Quantitative samples were collected from provinces including: Nam Dinh (coastal saline soil), Ha Nam (neutral alluvial soil), Ba Vi (Hanoi) (reddish yellow humus on the mountain), Bac Giang (infertile soil) At each quantitative sampling point, soil samples is collected according to the following or habitats: human - disturbed forest, shrub grassland, cultivated land with perennial plants and agricultura land with anual plants Samples collected for experimental fertilization were carried out in the agricultural land of the Red River Delta, including: soil without fertilization (ĐC), chemical fertilizer soil (CT1), soil with organic fertilization (CT2), soil with microbiological fertilizer (CT3), soil with fertilizer and organic fertilizer (CT4) 2.2.2 Methods of separation and treatment treatment specimens Filtering, analyzing and processing in oribatida samples according to specialized methods, wich is widely used in the world and Vietnam Filter oribatida sample according to the funnel Berlese –Tullgren method Filtering time is days and nights continuously at laboratory temperature conditions 27 - 30ºC The thick and hard shell of oribatida was bleached by soaking in lactic acid for a few days 2.2.3 Methods of analysis and classification Identificating, measuring and taking a photo of oribatida was performed directly through the two-eyed magnifying glass Labsc Euromex Arthema with 20 - 40 times magnification and the microscope Correct - Tokyo Seiwa Optical with 40 - 100 times magnification Identified and arranged oribatida according to Krivolutsky's classification system (1975), Balogh (1992, 2002), Vu Quang Manh (2007, 2015), Norton and Behan – Pelletier (2009), Schatz et al (2011), Subias (2013) and Ermilov (2015) In addition, some other related documents are also used The samples of oribatida were stored in glass tubes of size (Φ ~ 0.5) x (h = 5.0) cm with aqueous solution, that consisting of absolute alcohol supplemented and 3-5 drops of lactic acid and glycerin After that, all tubes are stored in large glass with pure alcohol for long-term preservation 2.2.4 Methods of data analysis and processing Data on species composition and distribution characteristics of the oribatida mite community are collected and synthesized according to mathematical statistical methods After that, they are analyzed and processed according to the following ecological indicators: dominant index (D), Shannon - Weiner index (H’), Peilou index (J ’) and analysize level similarity of oribatida mite communities by Bray – Curtis index CHAPTER III: RESEARCH RESULTS AND DISCUSSION 3.1 Species composition of oribatida mite community (Acari: Oribatida) in the Red River Delta, North Vietnam 3.1.1 Species composition of oribatida mite community and their distribution characteristics in the study area The study has identified 283 species of oribatida, belonging to 129 genera, 57 families, of which 49 species have not been identified (in the form of sp.) There are 64 species identified for the first time in the Vietnam and 106 species identified for the first time in the study area (compared with Vu Quang Manh, 2015 and Ermilov, 2015) Table 1: Species diversity of oribatida mite community (Acari: Oribatida) and their distribution characteristics in the Red River Delta, North Vietnam Type of soil Species composition Acaronychidae Grandjean, 1932 Loftacarus siefi Lee, 1981 (*) Stomacarus ciliosus Luxton, 1982 (*) Acaridae Leach, 1816 Mycetoglyphus fungivorus Oudemans, 1952 (**) Acotyledon batsyler Zachvatkin, 1941(**) Acotyledon sp Caloglyphus rodionovi Zachvatkin, 1973 (**) Caloglyphus sp Acarus sino Linne’, 1758 (**) Hypochthoniidae Berlese, 1910 Eohypochthonius crassisetiger Aoki, 1959 (*) 10 Malacoangelia remigera Berlese, 1913 11 Malacoangelia sp 12 Hypochthoniella miutissimus (Berlese, 1904) (*) Brachychthoniidae Thor, 1934 13 Liochthonius sp Cosmochthoniidae Grandjean, 1947 14 Cosmochthonius lanatus (Michael, 1885) Epilohmanniidae Oudemans, 1923 15 Epilohmannia cylindrica cylindrica (Berlese,1904) 16 Epilohmannia minuta pacifica Aoki, 1965 (*) 17 Epilohmannia ovata Aoki, 1961 (**) 18 Epilohmannia xena (Mahunka, 1983) 19 Epilohmannia sp.1 20 Epilohmannia sp.2 21 Epilohmannia sp.3 22 Epilohmannoides xena (Mahunka, 1983) (*) Lohmanniidae Berlese, 1916 23 Annectacarus africanus Balogh, 1961 (**) 24 Haplacarus javensis Hammer, 1979 (**) 25 Haplacarus pandanus Sengbusch, 1982 (**) 26 Haplacarus pairathi Aoki, 1965 27 Haplacarus porosus Hag et Clement, 1995 (**) 28 Haplacarus sp 29 Javacarus kuehnelti Balogh, 1961 30 Lohmannia javana Balogh, 1961 31 Meristacarus sp 32 Papillacarus aciculatus (Berlese, 1905) 33 Papillacarus hirsutus Aoki, 1961 34 Papillacarus pavlovskii (Bulanova - Zachvatkina, 1960) (**) 35 Papillacarus undrirostarus Aoki, 1964 36 Papillacarus gueyeae (Perez - Inigo, 1989) (*) Mesoplophoridae Ewing, 1917 37 Mesoplophora hauseri Mahunka, 1982 (**) (i) (ii) (iii) x x Type of habitat (iv) (v) RT N RT TC CLN x x x x x x x x x x x x x x x x x x CN N x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 38 Mesoplophora michaeliana Berlese, 1904 (**) Oribotritiidae Grandjean, 1954 39 Indotritia javensis (Sellnick, 1923) 10 Euphthiracaridae Jacot, 1930 40 Acrotritia ardua (Koch, 1841) 41 Acrotritia duplicata (Grandjean, 1953) 42 Acrotritia hyeroglyphica (Berlese, 1916) 43 Acrotritia sinensis Jacot, 1923 44 Acrotriti reticulata (Mahunka, 1988) (**) 11 Phthiracaridae Perty, 1841 45 Hoplophorella collaris (Balogh, 1958) (**) 46 Hoplophorella cuneiseta Mahunka, 1988 47 Hoplophorella floridae Jacot, 1933 48 Hoplophorella schauenbergi (Mahunka, 1978) (**) 49 Hoplophorella sp.1 50 Hoplophorella sp.2 12 Trhypochthoniidae Willmann, 1931 51 Allonothrus russeolus Wallwork, 1960 (*) 52 Archegozetes longisetosus Aoki, 1965 53 Trhypochthoniellus setosus Willman, kuriki et Aoki, 1989 (**) 13 Malaconothridae Berlese, 1916 54 Malaconothrus sp 55 Trimalaconothrus angustirostrum Hammer, 1966 56 Trimalaconothrus sp 14 Nothridae Berlese, 1896 57 Nothrus baviensis Krivolutsky, 1998 58 Nothrus gracilis (Hammer, 1961) 59 Nothrus montanus Krivolutsky, 1998 (*) 60 Nothrus silvestris Nicolet, 1855 (**) 61 Nothrus sp 15 Crotoniidae Thorell, 1876 62 Crotonia sp 63 Holonothrus sp 16 Nanhermanniidae Sellnick, 1928 64 Cyrthermannia sp 33 Nanhermannia Berlese, 1913 65 Nanhermania sp 17 Hermanniidae Sellnick, 1928 66 Hermanniag ladiata Aoki, 1965 67 Hermannia similis Balogh et Mahunka, 1967 68 Hermannia sp 18 Neoliodidae Sellnick, 1928 69 Neoliodes theleproctus (Hermann, 1804) 19 Plateremaeidae Tragardh, 1926 70 Plateremaeus sp 20 Pheroliodidae Paschoal, 1987 71 Pheroliodes intermedius (Hammer, 1961) (**) 21 Damaeidae Berlese, 1896 72 Metabelba orientalis Balogh et Mahunka, 1967 22 Zetorchestidae Michael, 1898 73 Zetorchestes saltator Oudemans, 1915 23 Compactozetidae Luxton, 1988 74 Sphodrocepheus tuberculatus Mahunka, 1988 x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 10 x x x x x x x x x x x x x x x x x x x x x x x x 193 Rhabdoribates siamensis Aoki, 1967 194 Scheloribates atahualpensis Hammer, 1961 (**) 195 Scheloribates cruciseta Vu et Jeleva, 1987 196 Scheloribates elegans Hammer, 1958 (**) 197 Scheloribates fimbriatus fimbriatus Thor, 1930 198 Scheloribates fimbriatus africanus Wallwork, 1964 (**) 199 Scheloribates kraepelini (Berlese, 1908) (*) 200 Scheloribates laevigatus (Koch, 1835) 201 Scheloribates latipes (C.L.Koch, 1841) 202 Scheloribates matulisus Corpuz-Raros, 1980 (**) 203 Scheloribates obtusus Petzen, 1963 (**) 204 Scheloribates pallidulus (Koch, 1841) 205 Scheloribates parvus Pletzen, 1963 (*) 206 Scheloribates praeincisus (Berlese, 1910) 207 Scheloribates sp.1 208 Scheloribates sp.2 209 Scheloribates sp.3 210 Scheloribates grandiporosus (Hammer, 1973) (**) 211 Bischeloribates dalaweus Corpuz-Raros, 1980 (**) 212 Bischeloribates heterodactylus Mahunka, 1988 (*) 213 Bischeloribates praeincisus (Berlese, 1916) (**) 214 Topobates coronopubes (Lee et Pajak, 1990) (**) 52 Oripodidae Jacot, 1925 215 Cosmopirnodus tridactylus Mahunka, 1988 216 Oripoda excavata Mahunka, 1988 217 Subpirnodus mirabilis Mahunka, 1988 218 Truncopes orientalis Mahunka, 1987 53 Protoribatidae J Balogh et P Balogh, 1984 219 Perxylobates brevisetus Mahunka, 1988 220 Perxylobates crassisetosus Ermilov et Anichkin, 2011 (*) 221 Perxylobates guehoi Mahunka, 1978 (*) 222 Perxylobates taidinchani Mahunka, 1976 (**) 223 Perxylobates thanhhoaensis Ermilov, Vu, Trinh et Dao, 2010 (*) 224 Perxylobates vermiseta (Balogh et Mahunka, 1968) 225 Perxylobates vietnamensis (Jeleva et Vu, 1987) 226 Perxylobates sp 227 Protoribates capucinus (Berlese, 1908) 228 Protoribates gracilis (Aoki, 1982) 229 Protoribates lophothrichus (Berlese, 1904) 230 Protoribates monodactylus (Haller, 1804) 231 Protoribates paracapucinus Mahunka, 1988 (*) 232 Protoribates rodriguezi (Mahunka, 1988) (**) 233 Protoribates bipilis (Hammer, 1972) (**) 234 Protoribates bisculpturatus (Mahunka, 1988) (*) 235 Protoribates duoseta (Hammer, 1979) 236 Protoribates maximus (Mahunka, 1988) 237 Protoribates sp 238 Setoxylobates foveolatus Balogh et Mahunka, x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 14 x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 1967 239 Vilhenabates sp 54 Haplozetidae Grandjean, 1936 240 Lauritzenia flagellifer (Hammer, 1967) 241 Trachyoribates areolatus Balogh, 1958 242 Trachyoribates punctulifer Balogh et Mahunka, 1979 243 Trachyoribates shibai (Aoki, 1976) (**) 244 Trachyoribates trimorphus Balogh et Mahunka, 1979 245 Trachyoribates sp.1 246 Trachyoribates sp.2 247 Trachyoribates sp.3 248 Peloribates pseudoporosus Balogh et Mahunka, 1967 249 Peloribates gressitti Balogh et Mahunka, 1967 250 Peloribates guttatoides Hammer, 1979 (*) 251 Peloribates kaszabi Mahunka, 1988 252 Peloribates stellatus Balogh et Mahunka, 1967 253 Peloribates rangiroaensis Hammer, 1972 254 Peloribates sp 255 Peloribates yoshii (Mahunka, 1988) (**) 55 Parakalummidae Grandjean, 1936 256 Neoribates aurantiacus (Oudemans, 1913) 257 Neoribates jacoti (Balogh et Mahunka, 1967) 56 Galumnidae Jacot, 1925 258 Allogalumna upoluensis Hammer, 1973 (*) 259 Dimidiogalumna azumai Aoki, 1996 (*) 260 Galumna aba Mahunka, 1989 (*) 261 Galumna coronata Mahunka, 1992 (*) 262 Galumna discifera Balogh, 1960 263 Galumna flabellifera Hammer, 1958 264 Galumna flabellifera orientalis Aoki, 1965 265 Galumna khoii Mahunka, 1989 266 Galumna obvia (Berlese, 1914) (*) 267 Galumna sp 268 Pergalumna corolevuensis Hammer, 1971 (**) 269 Pergalumna indivisa Mahunka, 1995 (**) 270 Pergalumna granulata Balogh et Mahunka, 1967 271 Pergalumna kotschyi Mahunka, 1989 272 Pergalumna longisetosa Balogh, 1960 (*) 273 Pergalumna margaritata Mahunka, 1989 (*) 274 Pergalumna nuda Balogh, 1960 (*) 275 Pergalumna pertrichosa Mahunka, 1995 (**) 276 Pergalumna punctulata Balogh et Mahunka, 1967 277 Pergalumna remota (Hammer, 1968) (**) 278 Pergalumna sp 279 Trichogalumna subnuda Balogh et Mahunka, 1967 280 Trichogalumna vietnamica Mahunka, 1987 57 Galumnellidae Piffl, 1970 281 Galumnella cellularis Balogh et Mahunka, 1967 282 Galumnella sp 283 Galumnella csavasorum (Mahunka, 1994) (**) x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 15 x x x x x x x x x x x Total: 283 species, 129 genera, 57 families New species for Vietnam: 64 New species for study area: 107 86 179 178 78 27 95 127 118 120 117 Note: Type of habitat: RTN: natural forest, RT: human - disturbed forest, TCCB: shrub grassland, CLN: cultivated land with perennial plants, CNN: agricultural land with anual plants Soil type: (i): coastal saline alluvial soil, (ii): sour alluvial soil, (iii): neutral alluvial soil, (iv): reddish yellow humus on the mountain, (v): infertile gray soil Symbol: new species for the study area (*), new species for Vietnam (**) The number of species of oribatida in each province and city change from 25 species to 144 species There are no species wich present in all provinces and cities in the study area Scheloribates laevigatus is the most common species, present in 10 out of 11 provinces and cities 3.1.2 Classification structure of oribatida mite community in the study area The oribatida mite community in the Red River Delta has been identified 283 species, 129 varieties, 57 families, 35 superfamilies In each family, there are to 18 genera and most of families have only - genus The number of species in each family is – 36, in which, 49.12% of them have only to species Oppiidae has the largest number of genera and species with 18 genera and 36 species Scheloribatidae is also a diverse family with 10 genera (accounting for 17.54% of total genera) and 30 species Table 2: Classification structure of oribatida mite community (Acari: Oribatida) in the Red River Delta Family Acaronychidae Acaridae Hypochthoniidae Brachychthoniidae Cosmochthoniidae Epilohmanniidae Lohmanniidae Mesoplophoridae Oribotritiidae 10 Euphthiracaridae 11 Phthiracaridae 12 Trhypochthoniidae 13 Malaconothridae 14 Nothridae 15 Crotoniidae 16 Nanhermanniidae 17 Hermanniidae 18 Neoliodidae 19 Plateremaeidae 20 Pheroliodidae 21 Damaeidae 22 Zetorchestidae 23 Compactozetidae 24 Astegistidae 25 Ceratoppiidae 26 Eremulidae 27 Damaeolidae Number of genus 1 1 1 2 1 1 1 1 Number of species 1 14 3 2 1 1 1 3 16 Percentage of total number of genera (%) 1,55 3,10 2,33 0,78 0,78 1,55 5.43 0,78 0,78 0,78 0,78 2,33 1,55 0,78 1,55 1,55 0,78 0,78 0,78 0,78 0,78 0,78 0,78 0,78 0,78 1,55 0,78 Percentage of total species (%) 0,71 2,12 1,41 0,35 0,35 2,83 4,95 0,71 0,35 1,77 2,12 1,06 1,06 1,77 0,71 0,71 1,06 0,35 0,35 0,35 0,35 0,35 0,35 1,06 0,35 1,06 0,35 28 Eremobelbidae 29 Basilobelbidae 30 Eremellidae 31 Oppiidae 32 Suctobelbidae 33 Tetracondylidae 34 Otocepheidae 35 Carabodidae 36 Tectocepheidae 37 Microtegeidae 38 Cymbaeremaeidae 39 Scutoverticidae 40 Austrachipteriidae 41 Microzetidae 42 Achipteriidae 43 Oribatellidae 44 Heterozetidae 45 Ceratozetidae 46 Punctoribatidae 47 Chamobatidae 48 Mochlozetidae 49 Oribatulidae 50 Liebstadiidae 51 Scheloribatidae 52 Oripodidae 53 Protoribatidae 54 Haplozetidae 55 Parakalummidae 56 Galumnidae 57 Galumnellidae 18 2 1 2 1 1 1 10 5 36 10 4 1 2 1 30 21 16 23 0,78 1,55 0,78 13,95 1,55 1,55 0,78 2,33 1,55 0,78 0,78 0,78 2,33 1,55 1,55 0,78 0,78 1,55 0,78 0,78 1,55 0,78 0,78 7,75 3,10 3,88 3,10 0,78 3,88 1,55 1,06 0,71 0,35 12,72 2,12 3,53 1,41 1,41 2,12 0,71 0,35 0,35 1,41 0,71 1,06 0,71 0,71 1,06 0,35 0,35 0,71 1,77 0,35 10,60 1,41 7,42 5,65 0,71 8,13 1,06 Scheloribates and Protoribates are the two most popular genera, appear in all provinces and cities in the study area Scheloribates is the largest genus with 16 species Most genera have only to species, in particular, there are 80 genera (accounting for 62.02% of total genera) have only species 3.1.3 The comparison of oribatida mite community in the Red River Delta with oribatida mite community in the Northwest and North Central regions The oribatida mite community in the Red River Delta is considered and compared to oribatida mite communities in the Northwest and North Central regions The results showed that oribatida mite community in the Red River Delta had the most number of species identified 17 Figure 1: Similar diagram of species composition of oribatida mite community in the Red River Delta, Northwest and North Central regions Note: ĐBSH: Red river delta, BTB: North Central, TB: Northwest Analysis of species composition of oribatida mite community in areas showed that, species composition of oribatida mite communities in the Red River Delta and the Northwest region are closest Species composition of oribatida mite community in the North Central region is the most different 3.2 The oribatida mite community structure according to habitat type 3.2.1 Species composition and distribution characteristics of oribatida mite communities in habitats In four types of habitats: human - disturbed forest, shrub grassland, cultivated land with perennial plants, agricultural land with anual plants in the study area, a total of 255 species of arthropod were identified, belonging to 111 varieties and sub-species, 57 families Number of species of oribatida mite community in each habitats decreasing in order: human - disturbed forest (127 species)> cultivated land with perennial plants (120 species)> shrub grassland (118 species)> agricultural land with anual plants (117 species) The percentage of species that present in all habitats is not high (14.51% of total species in habitats) but the percentage of species that only present in one type of habitat is quite high (49.80% of total species in habitats) 3.2.2 The average population density of oribatida mite community in types of habitats studied The average population density of oribatida mite community in each habitat decreases in order: human disturbed forest (4987 individual/m2) > shrub grassland (4773 individual /m2) > agricultural land with anual plants (4253 individual /m2) > cultivated land with perennial plants (3580 individual /m2) The oribatida mite community in cultivated land with perennial plants is the least developed in terms of both the number of species and the number of individuals 3.2.3 The structure of the dominant species group of oribatida mite community in types of habitats The number of dominant species of oribatida mite community in each habitat ranges from to species The oribatida mite community in cultivated land with perennial plants has the most dominant species and oribatida mite community in human - disturbed forest has the least dominant species In each community, there is a diferent group of dominant species and there is very little overlap of dominant species among habitats There are no species that dominate in all four study habitats There are 11 species (accounting for 84.62% of the dominant species) only dominate on one type of habitat Table 3: The structure of dominant species group of oribatida mite communities in studied habitats Dominant species Javacarus kuehnelti Mesoplophora michaeliana Plateremaeus sp Furcoppia sp Congoppia deboissezoni Striatoppia opuntiseta Scheloribates elegans Bischeloribates heterodactylus Bischeloribates praeincisus RT Dominant index (%) TC CLN CNN 5,80 14,46 5,80 5,17 10,19 5,59 5,54 6,28 18 9,87 7,26 10 Perxylobates guehoi 5,03 11 Perxylobates vietnamensis 5,03 12 Protoribates monodactylus 30,87 13,32 13 Galumna flabellifera orientalis 6,70 Note: RT: human - disturbed forest, TCCB: shrub grassland, CLN: cultivated land with perennial plants, CNN: agricultural land with anual plants 3.2.4 The Pielou (J ’) and Shannon - Wiener (H’) index of oribatid mite community in types of hábitats Pielou (J ’) index The J’ index was used to compare the level of uniformity in the distribution of individual to species in the communities in the study habitats The J ’index of oribatida mite community in the study habitats ranges from 0.71 to 0.86 and decrease in order: human - disturbed forest > cultivated land with perennial plants > agricultural land with anual plants > shrub grassland The oribatida mite community in human - disturbed forest habitat is evaluated to be most uniformly developed and the oribatida mite community in shrub grassland is evaluated to be less uniform and less stable Shannon - Wiener (H’) index The H’ index was used to compare the diversity of oribatida mite communities in four different habitats, in the study area, at the same time H' index of the oribatida mite communities in four habitats decrease in order: human - disturbed forest (3.93)> cultivated land with perennial plants (3.73)> agricultural land with anual plants (3.64)> shrub grassland (3.21) Among four habitats studied, oribatida mite community in human - disturbed forest has developed most diverse and stable, both qualitatively and quantitatively The uniform development of the community or the level of balance between species in the community plays an important role in the diversity of the community 3.2.5 The similarity of oribatida mite communities in types of habitats Figure 2: Similar diagram of the oribatida mite community structure in the study hábitats Note: RT: human - disturbed forest, TCCB: shrub grassland, CLN: cultivated land with perennial plants, CNN: agricultural land with anual plants The similarity of oribatida mite communities in the study habitats is assessed through the Bray – Curtis index The similar index of oribatida mite communities in study habitats range from 28.10% to 42.53% The oribatida mite community in shrub grass and in cultivated land with perennial plants has the largest similarity (42.53%) The oribatida mite community in human - disturbed forests and shrub grasslands is considered to be 19 the least close, with the similarity index of 28.10% In general, the degree of similarity in pairs of oribatida mite communities in habitats: shrub grassland, cultivated land with perennial plants, agricultural land with anual plants is quite high and equal The oribatida mite in human - disturbed forest is the most isolated, the ratio of similarity to the oribatida mite community in other habitats is less than 30% 3.3 The oribatida mite community structure according to soil type and fertilizer regime 3.3.1 Species composition and distribution characteristics of oribatida mite communities in soil types The oribatida mite community in the Red River Delta is quantitatively studied in types of soil, including: coastal saline alluvial soil, neutral alluvial soil, red yellow ferralitic soil on limestone mountains and infertile gray soil Analysis of qualitative and quantitative samples collected in types of studied land, identified 255 species, 111 genera and 57 families The number of species in each type of soil decreases in the following order: neutral alluvial soil (179 species)> red yellow ferralitic soil on limestone mountains (178 species)> coastal saline alluvial soil (86 species)> infertile gray soil (78 species) There are 28 species of oribatida (accounting for 10.59% of total species on soil groups) that are present in types of studied soil Widely distributed species of oribatida are in the higher - class groups than in the lower - order groups In the four study soil types, oribatida mite community on neutral alluvial soil have the highest number of characteristic species and the highest rate of characteristic species There are 125 species (accounting for 44.17% of all species in soil types) that appear only in one type of soil Differences in the qualitative structure of oribatida mite community in the four types of studied land are quite clear and most clearly expressed in the characteristic species group 3.3.2 The average density of individuals and the structure of dominant species group of the oribatida mite community in soil types The average density of individuals of oribatida mite community The number of quantitative species in each soil type decreases in the following order: neutral alluvial soil (107 species)> red yellow ferralitic soil on limestone mountains (104 species)> and infertile gray soil (74 species)> coastal saline alluvial soil (65 species) The average individual density of oribatida mite community in types of soil decreases in the following order: neutral alluvial soil (6313 individuals/m 2)> coastal saline soil (4676 individuals/m2)> red yellow ferralitic soil on limestone mountains (3100 individuals/m 2)> infertile gray soil (3050 individuals/m2) Neutral alluvial soil suitable for oribatida mite communities grows in both the number of species and the number of individuals in the community In coastal saline soils, communities limit species composition, however, the level of development in the number of individuals in species is quite high The oribatida mite community in the reddish yellow ferralitic soil on the mountain has a high diversity of species composition, but the average individual density of the community is not high compared to the community in the other soil types This shows that the reddish yellow ferralitic soil on the mountain is suitable for many species to adapt, however the density of the community can be limited due to the organic matter content in the soil environment The structure of dominant species group of oribatida mite community in studied soil types In the four types of soil studied, there are a total of 10 dominant species, the dominant species are in low to high classification groups The number of dominant species of oribatida mite community in each soil type 20 ranges from to species Most species only dominate in one soil type and are not dominant in the other soil types Protoribates monodactylus is the only species that dominates in all soil types studied Table 4: The structure of dominant species group of oribatida mite community in the studied soil types Dominant species (i) Dominant index (%) (ii) (iii) 8,55 9,68 (iv) Mesoplophora michaeliana Plateremaeus sp Furcoppia sp 6,84 Congoppia deboissezoni 12,36 Scheloribates elegans 9,51 Bischeloribates heterodactylus 6,84 10,48 Bischeloribates praeincisus 6,65 Protoribates monodactylus 8,94 17,85 17,41 9,18 Protoribates paracapucinus 5,51 10 Galumna flabellifera orientali 5,81 Note: (i) coastal saline alluvial soil, (ii) neutral alluvial soil, (iii) reddish yellow ferralitic soil on limestone mountains, (iv) infertile gray soil The structure of dominant group is characteristic of oribatida mite community in each soil type There is little overlap in the dominant species composition among communities in these four soils In coastal saline soils, although the environment exists a significant limiting factor for species composition diversity, the community still form a group of species adapted and developed relatively stable This group of species is mostly in the highclass and widely distributed 3.3.3 The Pielou (J ’) index and shannon - weiner (H’) index of oribatida mite community in soil types (J ’) index The J’ index of oribatida mite community in soil types decreases in the following order: infertile gray soil (0.88)> coastal saline soil (0.81)> reddish yellow ferralitic soil on the mountain (0.78) > neutral alluvial soil (0.77) It can be assessed that the species in oribatida mite community in infertile gray soil develop most uniformly and most stable In coastal saline soils, although oribatida mite community is less diverse in species composition, the species in the community grow quite evenly The oribatida mite community in the neutral alluvial soil and in reddish yellow ferralitic soil on limestone mountains is equivalent in both quantity and uniformity among species in the community Shannon - Weiner (H’) index The diversity index of oribatida mite community in these soil types ranges from 3.39 to 3.81 and decreases in the order: infertile gray soil (3.81) > reddish yellow ferralitic soil on limestone mountains (3.63)> neutral alluvial soil (3.61)> coastal saline soil (3.39) The H’ index of the community is changed by the type of soil corresponding to the change of the J’ index more than the change of the number of species By evaluating the H’ index and the J’ index, it shows that these indicators are not separate but closely related The oribatida mite community infertile gray soil has significantly less number of species than the community in the neutral alluvial soil and reddish yellow ferralitic soil on limestone mountains but the community in this soil type has a higher H’diversity index Neutral alluvial soil and reddish yellow humus soil are considered suitable for the oribatida mite community to develop at the same level 21 3.3.4 The similarity of oribatida mite community in types of soil Figure 3: Similar diagram of oribatida community in types of studied soil Note: (i) coastal saline alluvial soil, (ii) neutral alluvial soil, (iii) reddish yellow ferralitic soil on limestone mountains, (iv) infertile gray soil The similar coefficient of oribatida mite community in the studied soils ranges from 19.65% and 39.92% The oribatida mite community in the neutral alluvial soil in the reddish yellow ferralitic soil on limestone mountains has the greatest similarity The similarity of the oribatida mite community in the red reddish yellow ferralitic soil on limestone mountains with the community in other land types is quite high and evenly, this coefficient ranges from 37.10% to 39.92% The similar coefficient of oribatida mite community in types of soil including coastal saline alluvial soil, neutral alluvial soil, and reddish yellow humus soil on the mountain is little difference, range from 37.14% to 39.92% The analysis of the similarity of oribatida mite community by type of soil and by type of hábitats show that between pairs of habitats, the degree of similarity is in a wider range Therefore, it can be assessed that the differentiation of the factors in the environment that affect on oribatida mite community is more pronounced by hábitat 3.3.5 Species composition of oribatida mite communities in the fertilizing regimes In this study, oribatida community was studied in the agricultural ecosystem on different fertilizing regimes, including: soil for chemical fertilizer (CT1), soil for organic fertilizer (CT2), soil for microbial fertilizer (CT3), soil for chemical and organic fertilizer (CT4) and non-fertilized soil (DC) The study has identified a total of 34 species of oribatida, belonging to 25 genera, 15 families Among them, species (accounting for 23.53% of total species) have not been identified (in the form of sp.) The number of species of oribatida collected in each fertilization regime is different and decreases in order: CT2 (21 species)> DC (19 species)> CT4 (17 species)> CT1 (16 species)> CT3 (12 species) Thus, the diversity of oribatida mite species composition increases in soil with organic fertilizer and decreases in soil with the remaining fertilizers Sch.laevigatus is the only species that appears in all types of fertilized and non-fertilized soils (accounting for 2.94% of total species) There are species (accounting for 20.59% of total species) present in four fertilization regimes, including: E cylindrica cylindrica, J kuehnelti, L kuehnelti, L palustris, P vermiseta, S foveolatus, P kaszabi There are species (accounting for 5.88% of total species) that appear on all 22 fertilization regimes and not present in non-fertilized soils, including: P kaszabi P vermiseta Arcoppia sp.1 appears on soil fertilizing organic but not in other fertilizer regimes 3.3.6 The average individual density of oribatida mite community in fertilization regimes The average inđiviual density of oribatida mite community in these fertilizing regimes is different and decreases in order: CT2 (15900 individuals/m2)> CT4 (10400 individuals/m2)> CT1 (7800 individuals/m2)> CT3 (4400 individuals/m2)> DC (2800 individuals/m2) The oribatida mite community in the fertilized soil has a higher density of individuals than the community in non-fertilized soils So that, fertilizer is a stimulus for the individual development of the species Thus, fertilizer application has a certain effect on the oribatida mite community structure and each type of fertilizer has different influence levels In the scope of this study, the research results show a very clear change in species composition and average individual density of oribatida mite community, in which communities in organic fertilizer soil show the strongest change in a positive direction in both the number of species and the number of individuals 3.4 Biological indicator role of oribatida mite community structure in the study area 3.4.1 The bioindicative role of the oribatida mite community for living habitat change Noti et al (2003) have shown that oribatida mite community depends on the type of habitat and the diversity of the community related to the level of human impact In Vietnam, the results of the study by Vu Quang Manh and his colleagues (1990) also showed that human impact on vegetation cover has a clear influence on the structure of microarthropoda community In this study, the relationship between the structure of oribatida mite community and the type of habitat is considered in habitats: human - disturbed forest, shrub grassland, cultivated land with perennial plants, agricultural land with anual plants According to the results of this study, the change of living conditions through types of hábitat has caused changes in oribatida communities both qualitatively and quantitatively The change in the characteristics of the oribatida community is quite evident even in species diversity, dominant species group structure, balance of development among species in the community and some ecological indicators Some of the ecological indicators analyzed also change acutely According to the analysis in section 3.2.1, if only comparing the number of species of the oribatida community in studied habitats, the difference does not show clearly However, the change in species composition structure of the oribatida community in habitats is very clear There are 127 oribatida species (accounting for 49.80% of total species on habitats) found only in one type of hábitat Among them, 36 species (accounting for 14.12% of total species) only appear in human - disturbed forest, 30 species (accounting for 11.76% of total species) are only present in shrub grassland, 36 species (accounted for 14.12% of total species) only in the cultivated land with perennial plants and 25 species (accounting for 9.80% of total species) only present in agricultural land with anual plants In particular, low-grade oribatida groups of the Acaronychoidae group are usually found only in agricultural land with anual plants out of species in this group were found only on agricultural land with anual plants that were not found in the other habitats Therefore, the presence of this oribatida group may be considered as a marker to assess the degree of environmental impact The data analyzed in section 3.2.2 also show that there is a change in the average density of individuals of the oribatida community in the studied habitats The development of individual numbers of species in the community is judged to be related to the nature of vegetation and the stability of the habitat Less diverse, less 23 varied plant composition at shrub grassland habitats makes the environment more specialized It is suitable for adaptive species groups to grow in number of individuals and create a certain limit for the diversity of species composition On the contrary, the diversity but often changes with the seasons, the cultivation of the crop structure is a beneficial factor for the development of diverse species and to be a limiting factor for the development of individual populations of species in the agricultural land landscape with anual plants Analyzing the structure of the dominant species group of the community oribatida showed that on each community, there are dominant dominant species groups and very few overlap dominant species among hábitats In particular, Pr.monodactylus is a dominant species, can be considered a specific species to soil habitat shrub grassland The number of individuals of this species accounts for nearly 1/3 of the total number of individuals collected on the hábitat The remarkable development of the species may be associated with the development of a specific plant in this habitat The analysis of the J 'and H' indexes of the oribatida community in habitats shows that, at agricultural land with anual plants, the habitat was unstable and at the shrub grassland habitat with specialized plants, the environment has a higher selectivity for oribatida These disadvantages of the environment make higher ecological flexibility species able to adapt and grow better At the same time, it also inhibits the less adaptive species In these cases, the dominant development of the adaptive species group has reduced the level of uniformity among species in the community Comparing communities of oribatida in births of human - disturbed forest, cultivated land with perennial plants, agricultural land with anual plants show that the analyzed quantitative ratios of the oribatida community include the J ’, H’ index and the average density of individuals all decrease with increasing levels of farming activity in each habitat This shows that the results of this study are also consistent with the findings of many previous studies that cultivate activities negatively affect the community of oribatida, they reduce the diversity and abundance of the community through altering the organic composition and soil environment characteristics From the data obtained in this study and the analysis given, the characteristics of the community structure are closely linked to the environmental conditions At the shrub grassland habitat, there are typical vegetation and habitat of agricultural land with anual plants that are clearly affected by agricultural cultivation activities, communities oribatida, which have specific species groups, clearly showing Through analysis of the community structure oribatida also showed that, among the types of habitats studied, the human - disturbed forest is a suitable and stable habitat for the developed oribatida community Thus, from the results obtained showed that the community structure of oribatida is closely related to the habitat in each habitat in the study area The characteristics of the oribatida community structure in each habitat are associated with the characteristics of the habitat Therefore, the results of the study are significant to add data as a scientific basis for the use of oribatida as an indicator of the change of habitat 3.4.2 The bioindicative role of the oribatida community for changes in soil type, fertilizer regime In this study, the community of oribatida was quantified and assessed the role of the indicator through types of land, including: coastal saline alluvial soil, neutral alluvial soil, eddish yellow ferralitic soil on limestone mountains and infertile gray soil Through the results and the analyzes presented in section 3.3, the comparison between the types of researched soil has been shown The variation in oribatida species diversity in the community clearly shows the change through the habitat types However, the change is also shown more 24 clearly in species composition The proportion of oribatida species appearing on all soil types is not high (10.59%) but the rate of oribatida species wich only appears on high soil type (42.75%) Analysis of species composition in soil types also shows that widely distributed species are in highergrade oribatida groups more than in low-level groups The specificity of the species composition of the oribatida community in each soil type is evident because there are 109 species of oribatida in this list appear only in one type of soil that was not found in other soil types studied Among them, 15 species are only present on coastal saline soils, 51 species of oribatida are only present on neutral alluvial soil, 28 species of oribatida are only present on the yellow ferralitic soil on limestone mountains and 15 species of oribatida are only present in infertile gray soil In particular, most of species belong to two groups of Acaronychidae and Acaridae are present on neutral alluvial soil but very few occur on the remaining soil groups On each of the different soil types, the community of oribatida has a typical dominant species group In coastal saline soil, there is a characteristic salinity factor, oribatida mite community is less diverse in species composition but form the dominant group of stable growth species In neutral alluvial soil and eddish yellow ferralitic soil on limestone mountains, communities have the same level of dominance Through the analysis of the structure of the dominant species group of the oribatida community according to the type of habitat, it has been shown that the difference in the level of development of this species in different habitats is more pronounced than the difference through different types of land This provides further evidence that the differentiation of habitats through different types of habitats influence to the structure of the community oribatida is more pronounced than the changes through the types of soil studied Thus, for oribatida, the change of habitat according to habitat is more selective than the change by soil type This shows the decisive role of vegetation for community structure oribatida The analysis of the oribatida community in soil types also shows that the community of oribatida in neutral alluvial soil and eddish yellow ferralitic soil on limestone mountains has the highest similarity coefficient Comparison between the soils studied, neutral alluvial soil and eddish yellow ferralitic soil on limestone mountains are the two most similar soil types They are all rich in protein, rich in humus Since then, the structure of crops cultivated on these two soils has many similarities Therefore, the habitat conditions of oribatida communities in these two soils have the most similarities Therefore, the largest similarity of the oribatida community in the above two types of soil indicated in this study has shown the decisive role of soil type in oribatida community structure On the other hand, the analysis of the structure of dominant species group of the oribatida community mentioned above also showed that Pr Monodactylus grows in these two environments at a similar level This analysis further clarifies the intimate relationship of oribatida mite community structure with soil type The data and analysis given is an important basis to show the indicator ability of the oribatida community for the change of habitat in the study area Although, there are some studies on the community of oribatida in some different fertilizing regimes, The comparison between these studies is difficult to implement because of the heterogeneity in scale and process Therefore, it is difficult to make general conclusions Most studies show that fertilizers have certain effects on the oribatida community and how it affects, in a positive or negative direction, depending on the nature of the fertilizer applied Analysis of the data given in section 3.3.6 shows that in the fertilized soil, there is a higher density of individuals than non-fertilized soil The oribatida community in the soil of microbial fertilizer has the density of individuals closest to the control community The density of the community of oribatida in the soil 25 fertilized with organic fertilizer changed the most This result can be explained that microbial fertilizer does not directly provide nutrients to the soil environment, they include nitrogen fixing microorganisms, digesting food in the soil, they impacts directly and indirectly to the soil environment more slowly So that, the community of oribatida on the soil of micro-organism fertilizer has a low density compared to the most control community The community of oribatida in organic fertilizer soil has a high density of individuals because the amount of organic fertilizer applied to the soil supplemented the food source so that the oribatida groups could thrive in the number of individuals This is considered as a positive directional effect of organic fertilizer applied to the community of oribatida Research by Kitasawa (1980) and Bielska et Paszewska (1977) also showed that green composting and manure can sometimes cause irritation to the community oribatida Thus, the results obtained in this study have provided important ecological information for the oribatida community in the Red River Delta The changes of the living environment closely related to the changes in the structure of the community have clearly demonstrated the biological indicator ability of oribatida at the level of species combination CONCLUSIONS AND SUGGESTION CONCLUSIONS In the Red River Delta, has identified 283 oribatida species (Acari: Oribatida), belonging to 129 genera and 57 families (49 species have not been identified as "sp.") The list includes 106 species, belonging to 39 genera and 12 families wich were recorded for the first time for the oribatida region of the Red River Delta; 64 species were first recorded for Vietnam In the studied area, the family Oppiidae Sellnick, 1937 is the largest with 36 species and 18 genera The species with the largest number of species is the Scheloribates Berlese, 16 species Scheloribates Berlese, 1908 is the largest genus with 16 species There are 78.95% of them only have 1-2 genera and 49.12% of them have only 1-2 species In particular, there are 17 families (accounting for 29.82% of the total families) have only genus and species The rate of genera having only species is high (accounting for 62.02% of total species) Scheloribates laevigatus Koch, 1835 is the most popular species Species composition of oribatida mite community in the Red River Delta, closer to the oribatida community in the Northwest than in the North Central region According to the habitat, oribatida species diversity decreases in the following order: Human - disturbed forest (identified 127 species)> Cultivated land with perennial plants (120 species)> Grasslands and shrubs (118 species)> Agricultural land with anual plants (117 species) The average individual density of the oribatida community in cultivated land with perennial plants is smallest (3580 individuals/m 2) and largest in human - disturbed forest (4987 individuals/m 2) The oribatida mite community in human - disturbed forest is the most stable and diverse (corresponding to J ’= 0.86 and H’ = 3.93) and oribatida mite community in shrub grassland is less uniform and less diverse (respectively J ’= 0,71 and H’ = 3.21) The community oribatida in Shrub grassland, Cultivated land with perennial plants and Agricultural land with anual plants forming a group of species closer ((similar coefficient 40.65% -42.53%) The oribatida community in the Human habitat disturbed forest has the most distinct species composition 26 According to soil type, the diversity of oribatida species decreases in the order: Neutral alluvial soil (169 species identified) >Reddish yellow ferralitic soil on limestone mountains (154 species) >Coastal saline alluvial soil (87 species) >Infertile gray soil (76 species) Average density of individual decreases in the following order: Neutral alluvial soil (6313 individuals/m 2) >Coastal saline soils (4676 individuals/m 2)> Eddish yellow ferralitic soil on limestone mountains (3100 individuals)/m 2) >Infertile gray soil (3050 individuals/m 2) The oribatida mite community in infertile gray soil is the most uniform (J ’= 0.88) and least uniform in neutral alluvial soil (J’ = 0.77) The H’ index of the oribatida community is highest in the infertile gray soil (H’= 3.81) and lowest in the coastal saline soil (H’ = 3.31) The community of oribatida in neutral alluvial soil and reddish yellow ferralitic soil on limestone mountains is equally stable and diverse, the community structure has the highest similarity (39.92%) It has been determined that the diversity of oribatida species increases when the soil is fertilized with organic fertilizer, decreases when fertilized with fertilizers: inorganic fertilizers, micro-organic fertilizers or a mixture of these two fertilizers At all fertilizer regimes, the density of the oribatida community was examined and increased the most in the fertilized soil The community structure of oribatida in species diversity and density is clearly related and varies according to habitat type, soil type and different fertilizer regimes Therefore, the results of this structural analysis will provide a scientific basis as a biological indicator for the transformation of soil ecosystems SUGGESTION Structure of oribatida mite community in the soil ecosystem changes in species composition diversity, individual density, dominant species group, sharp diversity, corresponding to the change of habitat conditions Therefore, they are potential indicators, which can be studied and investigated as bioindicators contributing to the protection and sustainable development of soil ecosystems Through initial research and evaluation of the changes in structure of oribatida mite community in different fertilizer regimes, it has been shown certain changes However, in this study, the data collected are still limited Therefore, it is necessary to further develop this research direction in order to provide the necessary information that, according to world experts, is still lacking in the tropical region in general and in Vietnam to build a scientific basis for the use of oribatida as a bioindicator PUBLISHED WORKS RELATED TO THE THESIS Lai Thu Hien, Vu Quang Manh (2018), “Diversity of species composition and distribution characteristics of the oribatida mite community (Acari: Oribatida) according to soil type and habitat in the Red River Delta, Vietnam”, Journal of Science and Technology, VNU-HCM, 2(6), pp.11 – 22 Lai Thu Hien, Vu Quang Manh (2017), “Characteristics of distribution according to the habitat of the oribatida mite community (Acari: Oribatida) in Ba Vi, Hanoi”, - Yearbook to celebrate the 35th anniversary of the establishment of Ho Chi Minh University of Technology and Food, pp – 13 Lai Thu Hien, Do Thi Duyen, Vu Quang Manh (2017), “The close relationship between soil type and oribatida mite community structure (Acari: Oribatida) in the Red River delta, Vietnam”, Journal of Science and Technology, VNUHN, 33(4), pp 28 – 35 Lai Thu Hien, Vu Quang Manh (2015), “Characteristics of distribution according to the habitat of the structure of oribatida mite community (Acari: Oribatida) in Yen The, Bac Giang”, - Scientific Report, 27 Conference on Ecology and Biological Resources, Publisher of Natural Science and Technology, pp 1384 1388 Lai Thu Hien, Nguyen Huy Tri, Ha Tra My, Pham Thi Lien, Vu Quang Manh (2016), “Sample collection of oribatida species (Acari: Oribatida) in Vietnam at Hanoi National University of Education”, Scientific report, Second National Conference of Vietnam Museum of Nature Museum, Publisher Science and Technology National Science, H., pp 437 - 445 Vu Quang Manh, Lai Thu Hien, Ha Tra My (2019), “Oribatida mite community (Acari: Oribatida) in the mangrove forest of the Cat Ba Biosphere reserve, Nothern Vietnam”, Bulgarian Academy of Sciences Journal (Accepted) Vu Quang Manh, Dao Duy Trinh, Nguyen Hai Tien, Nguyen Huy Tri, Lai Thu Hien, Ha Tra My, Do Thi Duyen (2016), “Systermatic study and zoogeographical characteristic of the fauna Oribatid (Acari: Oribatida) in the soil ecosysterm”, - Journal of environmental economics (3), pp 179 – 189 Vu Quang Manh, Nguyen Huy Tri, Lai Thu Hien (2014), “Diversity of species composition of the oribatida community (Acari: Oribatida) in forest soil ecosystem, Cat Ba national park, Hai Phong city”, Scientific Report, The 8th National Scientific and Entomology Conference, Vietnam Society of Entomology, pp 916 - 928 Vu Quang Manh, Lai Thu Hien, Nguyen Huy Tri (2013), “Diversity of species composition of the oribatida community (Acari: Oribatida) and their distribution in soil ecosystems, Cat Ba national park, Hai Phong city”, Scientific Report, The fifth National Scientific Conference on Ecology and Biological Resources, Vietnam Academy of Science and Technology, Hanoi October 18, 2013, pp 1491 – 1497 28 ... community (Acari: Oribatida) in the Red River Delta, North of Vietnam » Objectives of the study Study on species composition and variation of oribatida mite (Acari: Oribatida) community in the Red river... contribution to biodiversity conservation research 1.2 Study on oribatida mite (Acari: Oribatida) in Vietnam In Vietnam, the first study on oribatida mite was conducted in 1967 By 2013, the Vietnamese oribatida... mite (Acari: Oribatida) in the Red river Delta The first study on the group of microarthropda in the Red River Delta was conducted in 1982 From then to 2004, the number of studies was very little