Number of Species and Average Density of Oribatid Mite Communities During the Diurnal Cycle


(Pao li, 1908); M. minusminus (Paoli, 1908); O. nova (Oudemans, 1902); T. minor

Berlese, 1903.

+ There were 6 species distributed at two survey times (accounting for 14.63% of the total number of species in the day-night cycle): E. crassisetiger Aoki, 1959; S. ruzsinszkyi Mahunka, 1983; S. minima Hammer, 1979; S. ornata (Hammer, 1979); S. africanus (Wallwork, 1964);

P. kaszabi Mahunka, 1988.

There are 13 species distributed only at one survey time (accounting for 31.70% of the total number of species in the day-night cycle), specifically:

+ At 12:00, there were 5 species: C. lata Aoki, 1961; U. clavatus Aoki, 1967; N. crisposetosa (Hammer, 1979); A. cocuyana (Balogh, 1984) and Q. quadricarinata (Michael, 1885).

+ At 18:00 there were 4 species: C. lanatus (Michael, 1885); M. brevipectinata Suzuki, 1976; S. sabahensis Mahunka, 1988; S. magnifera (Mahunka, 1978).

+ At 24:00 there are 4 species, specifically: S. quinquenodosa Balogh, 1968;

Perxylobates sp.; P. margaritata Mahunka, 1989, M. calcarata (Mahunka, 1978).

Thus, the data shows that the species are distributed quite widely between the time points. In particular, it is observed that a large number of taxa are concentrated at all four time points: 6:00 - 12:00 - 18:00 - 24:00, similar to a certain time point. In the four survey times, the time point 6:00 has the lowest number of recorded species-level taxa, the number of taxa increases and reaches the highest at 12:00 and 18:00.

3.4.2. Biodiversity in the day-night cycle

From the data in table 3.14 and figure 3.19, it can be seen that:

Between the time points, the number of species fluctuated from 14 to 25, the highest at 16:00 and 18:00 with 25 species (accounting for 60.97% of the total number of species), at 24:00 it decreased to 20 species (accounting for 48.78% of the total number of species), the lowest decrease at 6:00 with only 14 species (accounting for 34.14% of the total number of species). The difference in the number of species recorded between the time points was statistically significant with (P<0.05).


So in general, in the four survey times, the number of species is usually highest in the period from 12:00 to 18:00 and lower in the other two times. This fluctuation seems to be associated with the fluctuation of the day-night cycle with the most obvious changes in temperature, light, etc.

Number of species

30

Individual MDT/m 2

30000

25

25000

20

17240

20

20000

0

15

15000

10

MDT

S

6760

10000

5

5000

0

6:00

12:00

18:00

24h00

0

Day and night cycle

25

25

2

416

14


4560

Figure 3.19. Number of species and average density of oribatid mite communities during the day-night cycle

The average density (MDTB, individuals/m 2 ) of the four time points ranged from 4560 (individuals/m 2 ) - 24160 (individuals/m 2 ). The average density tended to decrease gradually from 12:00 (24160 individuals/m 2 ) > 18:00 (17240 individuals/m 2 ) > 24:00 (6760 individuals/m 2 ) > 6:00 (4560 individuals/m 2 ). Thus, it can be seen that the number of species and MDTB of individuals have similar fluctuations.

with the number and density usually peaking between 1200 and 1800, and the lowest at 6000 in the morning.

From the data in table 3.14 and figure 3.20 it can be seen that:

Species richness (d) of the oribatid mite community reached its highest at 18:00 with an average of 3.02 ± 0.29, the highest was 3.33 and the lowest was 2.76. Next was 12:00 with 2.76 ± 0.91, the highest was 3.48 and the lowest was 1.74. At 24:00 it reached 2.6 ± 1.04, the highest was 3.45 and the lowest was 1.44. Species richness was lowest at 6:00 with 2.1 ± 0.42, the highest was 2.53 and the lowest was 1.7. The average species richness index (d) at different times was statistically significant (P<0.05).


Table 3.14. Some quantitative indices of the oribatid mite community during the day-night cycle

Day and night cycle

Index

6:00

12:00

18:00

24h00

S

14

25

25

20

Average population (individuals/m 2 )

4560

24160

17240

6760

d

2.1 ± 0.42

2.76 ± 0.91

3.02 ± 0.29

2.6 ± 1.04

J'

0.78 ± 0.11

0.65 ± 0.19

0.75 ± 0.19

0.80 ± 0.21

H'

1.59 ± 0.10

1.75 ± 0.56

2.00 ± 0.33

1.63 ± 0.67

1-Lambda'

0.74 ± 0.08

0.72 ± 0.16

0.80 ± 0.12

0.78 ± 0.16

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Number of Species and Average Density of Oribatid Mite Communities During the Diurnal Cycle


The uniformity (J') of the oribatid mite community between time points was generally not high, ranging from 0.65 ± 0.19 to 0.80 ± 0.21. (J') reached its highest at 24:00 on average with 0.80 ± 0.21, the highest was 0.95 and the lowest was 0.55, this index gradually decreased in the order 24:00 (0.80 ± 0.21) > 6:00 (0.78 ± 0.11) > 18:00 (0.75 ± 0.19) > 12:00 (0.65 ±

0.19). The average uniformity index (J') at different times was statistically significant (P<0.05).

4.5 Indicators

4

3.5

3

2.5

2

1.5

1

0.5

0


2.1


2.76


3.02


2.6


d

J'

H'

1-Lambda'

6:00 12:00 18:00 24:00 Day and night rhythm

Figure 3.20. Diversity of the oribatid mite community during the day-night cycle


The data show that in general, the reverse dominance of the community is not high, proving that there is a possibility of dominant species appearing in all four research periods, specifically:

The negative dominance (1 -λ) of the community fluctuated from 0.72 ± 0.16 to 0.80 ± 0.12, of which the highest was at 18:00, the average was 0.80 ± 0.12, the highest was 0.9, the lowest was 0.67, this index gradually decreased to 24:00 with 0.78 ± 0.16, the highest was 0.9, the lowest was 0.6. At 6:00, it reached 0.74 ± 0.08, the highest was 0.81, the lowest was 0.66. This index was lowest at 12:00 with 0.72 ± 0.16, the highest was 0.9, the lowest was 0.6. The average difference between the time points was statistically significant (P<0.05). Thus, the dominance index will be opposite to this value, highest at 12:00, or the possibility of the dominant species appearing at this time is very high, the dominance gradually decreases in the order 12:00 6:00 24:00 18:00, because the average inverse dominance index at the different times is statistically significant (P<0.05), so the dominance index is also statistically significant between the times.

Time

6:00

12:00

18:00

24h00

100




80


Cumulative Dominance%

60


40


20


0

1 10 100

Species rank


Figure 3.21. K-dominance curve showing species diversity during the day-night cycle

Figure 3.21 shows that the k-dominance curve in this graph has three times with the three lowest curves: 18:00 - 12:00 - 24:00, these are also the three times with the highest diversity (H'), specifically the highest average species diversity (H') at


At 18:00, the index reached 2.00 ± 0.33, the highest was 2.26, the lowest was 1.62. This index decreased in order, at 12:00, it reached 1.75 ± 0.56, the highest was 2.39 and the lowest was 1.37; at 24:00, the average was 1.63 ± 0.67, the highest was 2.35 and the lowest was 1.04, finally the species diversity level (H') reached the lowest value at 6:00 with an average of 1.59 ± 0.10, the highest was 1.67 and the lowest was 1.48. The average diversity index (H') between the different survey times was statistically significant (P<0.05).

Thus, 18:00 is the time with the highest level of species biodiversity and community richness. These values ​​are lowest at 6:00, while the community stability is highest at 24:00.

3.4.3. Dominant species structure

The dominant species structure of the oribatid mite community in four time periods is shown in Table 3.15, recording 9 dominant oribatid mite species with a ratio ranging from 5.26% - 52.63% in four time periods, specifically:

At 6:00 a.m., there were six dominant and very dominant species of oribatid mites, accounting for 5.26% - 52.63% of the total number of individuals, of which only R. ovulum ovulum was very dominant with a very high rate of 52.63%, the remaining five dominant species M. tropica, A. arcualis, M. tamdao, S. mahunkai, P. brevisetus, with rates ranging from 5.26% - 7.89%.

At 12:00, there were five dominant and very dominant species of oribatid mites, accounting for 7.12% - 38.91%, including two dominant species B. ornatissimus, A. arcualis with rates ranging from 7.12% - 7.78%, and three very dominant species M. minus minus, R. pinifera, R. ovulum ovulum with rates ranging from 10.43% - 38.91%.

At 18:00, there were five dominant and very dominant species of oribatid mites with a ratio ranging from 5.34% to 45.24%, of which two dominant species M. tamdao, R. pinifera, both accounting for 5.34%, and three very dominant species B. ornatissimus, A. arcualis , R. ovulum ovulum , accounting for a ratio of 11.14% to 45.24%.

At 24:00, there were four dominant and very dominant species of oribatid mites accounting for 5.92% - 50.3%, of which two dominant species A. arcualis, S. mahunkai, both accounting for 5.92% and two very dominant species B. ornatissimus, R. ovulum ovulum, accounting for 10.65% - 50.3%.


Table 3.15. Dominant oribatid mite species assemblages during the day-night cycle



STT


Species

D dominance (%)

6:00

12:00

18:00

24h00

1

Microtritia tropica Märkel, 1964

5.26




2

Multioppia tamdao Mahunka, 1988

6.14


5.34


3

Arcoppia arcualis (Berlese, 1913)

5.26

7.78

12.53

5.92

4

Scheloribates mahunkai Subias, 2010

7.89



5.92

5

Perxylobates brevisetus Mahunka, 1988

7.89




6

Rostrozetes ovulum ovulum (Berlese, 1908)

52.63

38.91

45.24

50.3

7

Ramusella pinifera Mahunka, 1988


15.73

5.34


8

Microppia minus minus (Paoli, 1908)


10.43



9

Berlesezetes ornatissimus (Berlese, 1913)


7.12

11.14

10.65


Thus: there are two species A. arcualis, R. ovulum ovulum, dominant or very dominant consecutively in all four survey periods, especially R. ovulum ovulum has a very high proportion, which can account for up to half of the individuals recorded at one time (Figure 3.28).

B. ornatissimus was dominant or very dominant at three survey times 12:00

- 18:00 - 24:00.

There were three dominant or very dominant species at two time points, M. tamdao was dominant at 6:00 and 18:00 with a ratio of 5.34% - 6.14%, S. mahunkai was dominant at 6:00 and 24:00 with a ratio of 5.92% - 7.89%, R. pinifera was dominant from 12:00 and 18:00 with a ratio of 5.34% - 15.73%.

The remaining three species were dominant at only one time point, M. tropica and P. brevisetus were dominant at 6:00 with 5.26% and 7.89%, respectively. M. minus minus was very dominant at 12:00 with 10.43%.


Thus, each time point has a different set and number of dominant species. In the four time points, the possibility of the dominant species group appearing is quite high, however, the dominance level at 12:00 tends to be more stable with the ratio between species groups having a small difference. The remaining three survey times all have a larger difference in the dominance ratio caused by a few species that are very dominant in the community. So it is possible that the 12:00 period has potential for species growth, but note that this is not a truly favorable factor because in this time condition, it also partly creates greater selectivity, there are also species that do not adapt to this time, and there are also new species that appear and are more active, specifically the data shows that from the 6:00 am period to the 12:00 noon period, the two species E. japonica and P. kaszabi are not seen again and there is the appearance of a new group of species including 13 species ( E. crassisetiger, C. lata, A. cocuyana, M. minus, O. minutissima, O. nova, Q. quadricarinata, N. crisposetosa, S. ruzsinszkyi, S. minima, S. ornata, T. minor, U. clavatus ).

During the four survey periods, it is noteworthy that there are two species that are continuously dominant and very dominant, Arcoppia arcualis and Rostrozetes ovulum ovulum , especially R. ovulum ovulum , which has a very high dominance level, even at 6:00 and 24:00, they account for half of the number of individuals in the community. During the research period, the data recorded that R. ovulum ovulum is also a very dominant species continuously in all four seasons in the tea monoculture habitat. In addition, A. arcualis, which is continuously dominant in four periods, was also found in all four seasons, and S. mahunkai , which is dominant in four seasons, was also found in this cultivated habitat with quite high numbers. Thus, the increase in dominance and dominance of these species is very significant, they can be considered as an indicator factor related to the perennial tea monoculture regime of the research area.

3.4.4. Similarity in species composition of oribatid mite communities during the day-night cycle

When analyzing the data using ANOSIM (Analysis of similarites), it was shown that the level of similarity between the times in the day-night cycle (R = -0.006; P = 0.47 > 0.05) had no statistically significant difference (P>0.05), between repetitions in a


time (R = 0.45; P = 0.01 < 0.05) the difference is statistically significant (P < 0.05), this also means that the species composition between times in the day-night cycle will be more similar, while the research habitat may have heterogeneous environmental conditions so the impact on species composition at each repetition will be more or less different.

The Bray-Curtis similarity coefficient (S jk ) was used to assess the similarity in species composition of oribatid mites between the survey periods. The data were presented in the form of CLUSTER analysis. The species richness data were converted to (square root) form before performing the similarity matrices.

Table 3.16. Similarity ratio of species composition of oribatid mites between four time points



6:00

12:00

18:00

24h00

6:00





12:00

48.57




18:00

55.26

79.59



24h00

69.80

58.91

64.13


Analysis of table 3.16 and figure 3.22 shows:

The similarity of oribatid species composition between the four time periods in the day-night cycle fluctuated quite high from 56.72% - 79.59%. The similarity of oribatid species composition between the four time periods can be divided into three community groups:

The first group includes the Oribatid mite community between 12:00 and 18:00 with a similarity ratio of >70%: specifically, the similarity of species composition reached the highest between 12:00 and 18:00, reaching 79.59%.

The second group consists of the oribatid mite community with similar species composition ratio (60%).

-70%): specifically, the similarity of species composition between 6:00 and 24:00 was 69.8%.

The third group includes the Oribatid mite community with species composition similarity <60%, with species composition similarity between the two groups at 12:00-18:00 and 6:00-24:00 at 56.72%.

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