1. Several studies examined soil micro-arthropods as indicators of environmental conditions. Abundance and diversity of mites and springtails decreased with increasing forest fire severity and pollution levels. 2. Leg deformities in oribatid mites increased with heavy metal pollution from a smelter. Some mite species were less abundant in polluted areas while others thrived. 3. In urban parks, springtail species richness and abundance decreased with increasing pollution. One species dominated the most contaminated site. 4. Application of the pesticide dimethoate reduced soil micro-arthropod populations by 59-69% compared to controls. Declines were greatest where dimethoate and metabol

1. Role of soil micro-arthropods as anRole of soil micro-arthropods as an
indicator of the environmentindicator of the environment
Romila Akoijam
Scientist (Entomology)
ICAR RC for NEH Region,
Manipur Centre, Lamphelpat,
Manipur

2. Contents:
• Introduction
• Descriptions of some soil micro-arthropods
• Indicator species
• Successful utilization of soil micro-arthropods as an
indicator of the environment
• Case studies
• Conservation of soil micro-arthropods
• Limitation of soil micro-arthropods
• Future thrust
• Acknowledgements

3. Soil Fauna
Micro-fauna
(0.02mm-0.20mm),
Meso-fauna
(0.20mm-10.24mm)
Macro-fauna
(10.24 mm and above).
Classification of Soil Fauna
(based on size)
Classification of Soil Fauna
(based on size)

4. General Characteristics of Soil micro-arthropods ?
• The soil micro arthropods with a body size of,
0.20mm-10.24mm which are usually extracted
by Berlese- Tullgren funnel.

5. • Unable to dig their own way in soil
• Inhabit soil crevices, pores, and hollows created
by larger animals

6. • Consume plant and animal residues
• Graze on soil fungi and bacteria
• produce faecal pellets
• Promote the formation of humus in the soil
• Maintaining soil structure
• After death they leave important nitrogenous waste

7. • Collembola (Springtails)
• Soil mite
• Protura
• Diplura
• Pseudoscorpion, etc.
Some soil micro-arthropods

8. • Head distinct
• Antennae one pair
• 6 abdominal segments
• Collophore or ventral tube on first
abdominal segment
• Furcula on 4th
abdominal segments

9. Fig. Some Collembollas

10. • Hardly sclerotised dorsal surface
• Palpi modified into thumb like process
(Actinedida)
• Chelicerae styliform or hook like (Actinedida)
• No stigma (Acaridida)
• Ocelli absent (Gamasida)

11. Fig. Some Soil mites

12. • Minute, slender, wingless insects
• Creamy - white in appearance
• Blind animal
• Absence of antennae
• Ectognathous with styliform mouth parts

13. Some Proturans

14. • Minute, slender, blind insects
• Pale - coloured in appearance
• Ectognathous and chewing type of
mouth parts
• A pair of cerci(forcep like) on last
abdominal segment
• Body covered with setae or
scales(rarely)

15. DipluransDiplurans

16. • Flat, pear-shaped body
• Yellowish-tan to dark-brown, with the
paired claws
• Two very long palpal chelae (pedipalps or
pincers), resemble the pincers of a
scorpion.

17. Pseudoscorpi
on
Pseudoscorpi
on

18.  Shred organic materials

19. • Stimulate microbial activity
• Mix microbes with their food
• Mineralize plant nutrients
• Promote plant nutrients

20. • Enhance soil aggregation
• Stimulate the succession of species
• Control pests (biocontrol agents)

21. What is Indicator species ?What is Indicator species ?
Organisms which respond to an impact by
their presence or absence, by a change of defined
characteristics or activities, or by an increased
content of a pollutant.
Luepke, 1979.The Hague,132-155.

22. Characteristics of indicatorCharacteristics of indicator
speciesspecies
• Common and widely distributed
• Persistence
• Easily identifiable
• Sensitive to any changes
• Dispersal habit

23. Successful utilization of soil
micro-arthropods as an indicator of the
environment

24. Soil mite as an indicator of the envt.
•Diversity is high, occur in high numbers
•Can be easily sampled in all seasons

25.  Most Soil Mites live in the organic horizons Most Soil Mites live in the organic horizons
(Lebrun and Van Straalen, 1995. Expt. Appl. Acarol.19: 361-380.).

26. (Gulvik M.E.,2007.Polish J.of Ecology, 55(3):415-440)
•Mite communities- extremely sensitive to
all types of soil disturbance
•Most oribatid mites have:
long life span,
low fecundity &
slow development and low dispersion
ability
•Changes in the dominance structure of
mite communities

27. Mites eat -
 vegetable detritus,
 livestock excrement (a rich food source).
(Chepstow, L.et al, 2007. J. of Archaeological Science. 34: 1178-118)
By these habits, the abundance of oribatid mites can be
used to indicate historical grazing patterns

28. Collembola - an indicator of the environment
•Occurs in large numbers
•Live in organic horizon
•Species diversity

29. Due to pollutants like Pesticides &
excessive nutrients,
diversity reduces when compared to soil in
a natural ecosystem
(Fiera,2009, Pesq. agropec.bras.,Brasília,v.44,n.8,868-873)
Soils contaminated with heavy metals
like Pb, Cd, Zn & Cu,
species richness decreases

31. 1.Abundance of soil micro-arthropods associated
with forest fire severity in Samcheok, Korea
(Kim et al., 2008)
• To investigate the association of soil arthropods
abundance from mountain sites
• Differential forest fire severities had been
influenced since April 2000
• The post-fire study was conducted from 2005 to
2007 at mountain sites (T1,T2,T3,C2 & Cont)

32. Abundance of soil micro-arthropods(mean no./m.sq) from mountain
sites with different burn severities during 2005-2007
Soil microarthropods
Burn severities
T1 T2 T3 C2
Cont Abundance % Abundance % Abundance % Abundance %
Abundance %
Arachnida
Acari
Oribatida
Gamasida
Prostigmata
Astigmata
Others(Acari)
Others
Insecta
Collembola
Hymenoptera
Formicidae
Others
TOTAL
824.7
552.7
59.8
171.7
35.3
15.3
19.9
66.4
42.1
4.8
13.8
2.8
1.2
1.6
1463.8
899.8
122.6
257.5
65.9
78.2
39.9
68.3
42.0
5.7
12.0
3.1
3.6
1.9
2817.3
1368.8
585.5
513.5
105.8
144.1
99.6
67.4
32.4
14.0
12.3
2.5
3.4
2.4
2930.7
1977.3
536.5
131.8
113.4
82.8
88.9
67.5
45.5
12.4
3.0
2.6
1.9
2.0
4382.3
2745.3
1004.0
317.3
70.5
115.0
130.3
68.
5
42.
9
15.
7
5.0
1.1
1.8
2.0
286.6 23.1 487.4 22.7 1146.5 27.4 1209.4 27.8 1598.7 25.
0
15.3 1.2 39.9 1.9 101.2 2.4 136.4 3.1 280.5 4.4
(SOURCE: Samcheok, J. of Asia-Pacific Entomology,11,2008,77-81)

33. • Total abundances of soil microarthropods –
Cont>C2>T3>T2>T1
• The same trends were found in major soil microarthropod groups of Acari,
Gamasida,Oribatida, and Collembola
• Abundance of soil microarthropods was highest in unburned control site(Cont) and
lowest in most severely burned site, T1.

34. Change of mean abundance of Oribatida (A) from mountain
sites with different burn severities during 2005 to 2007

35. Change of mean abundance of Gamasida (B)
from mountain sites with different burn severities
during 2005 to 2007

36. Change of mean abundance of Collembola
(C) from mountain sites with different burn
severities during 2005 to 2007

37. 2.Leg deformities of oribatid mites as an indicator
of envtl. pollution
• Collected soil samples from 9 separate sites at three distance
zones(3 sites/zone) in a well known pollution gradient of a Finnish
Cu-Ni smelter in the town Harjavalta, SW Finland
Zone Distance from Smelter
(km)
Pollution level
I <2 Heavily
II 4-6 Moderately
III 9-11 Unpolluted
Eeva T. et al, Sc. of the total Env.407(2009):4771-4776

38.  Sulphuric oxides & heavy metals (especially
As, Cd, Cu, Ni, Pb and Zn) are common
pollutants
 Ten focal oribatid species were used for
investigation.
 Berlese funnel
were used.

39. Three types of changes (pointed by arrows) in legs of
oribatid mites
Fig. Broken legs (a, c and e), a) Oribatula tibialis, c)
Conchogneta traegardhi & e) Furcoribula furcillata

40. Three types of changes (pointed by arrows) in legs of
oribatid mites Contd…
Fig. Missing leg (b) b. Hemileius initialis
Deformed leg (d and f) d. Chamobates cuspidatus, f. O. tibialis

41. Oribatid mite species, total numbers of individuals (in a sample
volume of 9 dm3
) at 3 different zones around a Cu - smelter
Source: Eeva et al.Sc.of the Total Envt.407(2009)4771-4776
Species Total Zone I Zone II Zone III
Adoristes ovatus
Caleremaeus monilipes
Chamobates cuspidatus
Conchogneta traegardhi
Eremaeus silvestris
Furcoribula furcillata
Hemileius initialis
Oribatula tibialis
Scheloribates latipes
Tectocepheus velatus
Other species
152
111
982
695
173
133
970
533
443
1575
5815
6(0)
2(0)
268(15)
0
4(1)
87(3)
505(9)
144(14)
27(0)
348(5)
1293
82(6)
109(5)
304(7)
372(32)
14(1)
17(2)
188(10)
197(21)
232(14)
613(9)
1706
64(4)
0
410(0)
323(8)
155(4)
29(3)
277(5)
192(19)
184(7)
614(6)
816
Numberof individuals 11582 2684 3834 5064

42. • Conchogneta traegardhi,
• Eremaeus silvestris and
• Scheloribates latipes
They are less abundant in the polluted environment
• Chamobates cuspidatus
The proportion of leg deformities was positively
related to the heavy metals.
• Hemileius initialis
More abundant in the polluted environment(acidic
condtn.)
• Some of the focal species, the number of deformed legs
increases when soil pH decreases.

43. 3.Biodiversity of Collembola in urban soils and
their use as bioindicators for pollution
• To evaluate the effects of pollutants on the
abundance and diversity of Collembola in
urban soils.
• Three parks (Cismigiu, Izvor and Unirea) in
downtown Bucharest were selected.
• Cismigiu park was highly contaminated with
Pb, Cd, Zn and Cu
Fiera C.,2009

44. Number of springtail individuals of each species
encountered in the three urban parks, Bucharest,
Romania.

45. Number of springtail individuals of each species
encountered in the three urban parks, Bucharest, Romania,
(Contd…)

46. Number of springtail individuals of each species
encountered in the three urban parks, Bucharest, Romania,
(Contd…)
SOURCE: Fiera C.(2009) Pesq. agropec. bras., Brasília, 44(8):868-
873,

47. Species richness with levels of pollution
(SOURCE: Fiera C.(2009) Pesq. agropec. bras., Brasília, v.44, n.8,868-
873)
Polluted parks Pollution level Species richness
Cismigiu Most 11
Unirea less 20
Izvor least 23
H.
thermophyla :
very abundant in
the most
polluted site
H.
thermophyla :
very abundant in
the most
polluted site
P. armata :
more abundant
in less polluted
area
P. armata :
more abundant
in less polluted
area

48. Numerical density of springtails found in three
urban parks in Bucharest, Romania.
SOURCE: Fiera C.(2009) Pesq. agropec. bras., Brasília,44(8):868- 873.

49. 4.Effect of Dimethoate Residues on Soil Micro-arthropods
Population in the Valley of Zendan,Yemen
• To screen the effect of overuse of Dimethoate and its
residues(0 -15 cm soil layer) on the soil micro-arthropods
population
• The valley divided into three stations, containing three treated
substations and three control substations each
• Average use of Dimethoate 40% E.C is 1-2 ml/L water
• Analyzed the total concentration of Dimethoate, and its
metabolite; Omethoate
(Ahssan et al., 2006)

50. Arthropods population in Zendan Valley after 5 days of
application of dimethoate
(SOURCE: Ahssan et al.(2006) J. Appl. Sci. Environ. Mgt., 10 (2) 37 – 41)
Station No. Sub-
Station
No.
Dimethoate
residues in treated
Station(mg/kg air
dried soil)
Omethoate
residues in
treated
Station(mg/kg
air dried soil)
No.of of soil microarthropods
extracted
Upstream 1
2
3
0.194
1.568
5.180
0.005
0.006
0.020
Midstream 4
5
6
5.068
2.324
1.368
0.020
0.014
0.001
Downstream 7
8
9
3.157
2.028
1.413
0.067
0.032
0.021
Control - farmsControl - farms
6.606.60
12.0012.00
7.677.67
6.006.00
15.0015.00
14.0014.00
9.009.00
4.334.33
15.6715.67
Treated - farmsTreated - farms
3.303.30
2.602.60
2.002.00
3.333.33
4.334.33
7.007.00
0.000.00
2.332.33
6.006.00

51. • Effect of Dimethoate & Omethoate residues - beyond the Total
Threshold Limit Concentration (TTLC) in soil (0.5 mg/kg)
• Significantly reduced the population of the non-target soil micro-arthropods Mites and
Collembolans
Significantly reduced the population of the non-target soil
micro-arthropods Mites and Collembolans
Reduction in the soil microarthropods population varied from
59% to 69% as compared to its population in control
substations
Maximum decline of soil microarthropods was found to be in
substations where the highest residues of Dimethoate and
Omethoate were recorded.

52. Conservation practices for soil micro arthropods
in the environment
SOURCE: agricultureguide.org/agriculture/news/

53. Organic agriculture enhances the number of species and
the abundance of many taxa compared with
conventional agriculture. (IFOAM, 2008)

54. Avoidance of pesticides & herbicides

55. Encourage to enhance biological cycles within the
farming system

56. Maintain to increase long-
term fertility of soils
Maintain to increase long-
term fertility of soils

57. • Maintain the genetic diversity of the
agricultural system and its surroundings
• Establish correlations between soil
biomass and moisture levels, pollutant
densities, crop situation, agricultural
practices

58. Enhance collaboration among soil
biology specialists and
agriculturists

59. Limitation of soil microarthropods in the envt.
Effects of moisture and temperature
Soft-bodied animals such as enchytraeids and
collembolans are sensitive to desiccation
during dry conditions
Seasonal temperature variations commonly
induce vertical movements of soil micro-
arthropods in the soil profile
Fecundity and sex ratio in the populations may
also be affected(Collembola)

60. Forest fertilisation :
 Abundances decrease shortly after additions of
solid fertilisers
 Ammonium nitrate applications - toxic effects &
Salt effects, can caused desiccation.
Disturbances:
Oribatida communities sensitive most
Many researchers have found strong effects, e.g.,
pollution, pesticides, fire, tillage, monoculture, etc.

61. Urban environments:
Oribatid mites to be sensitive indicators of
changing air quality
Humerobates rostrolamellatus (Oribatid) is
highly sensitive to air pollution and has been
tested in the laboratory and in the field
Popn
structure, species richness and
reproduction of oribatid mites also are –vely
effected by the higher dose of heavy metals in
urban envt.

62. Melanisation in Collembola
Less variation has been observed in
prostigmatid mites
 Melanism increases with higher altitude
or latitude
UV radiation

63. Future thrustFuture thrust
• Many modern soil biologists consider the soil
microarthropods to be the last biotic frontier by their sheer
numbers, diversity of species, difficult taxonomic
compositions and numbers of undescribed species
• Soil micro-arthropods is perhaps one area that has yet
remained least explored scientifically.
• The National Biodiversity Strategy and Action Plan
(NBSAP) is a guideline preparation of strategies and action
plans for protection, promotion and conservation of national
biodiversity wealth including soil microarthropods.

64. Acknowledgements:Acknowledgements:
 Dr.Y.S.Mathur, NC, AINP on Whitegrub,Durgapur,
Jaipur
 Dr.A.A.L.H.Barooah, Prof, Deptt. Of Ento., AAU, Jorhat
 Mr.Apurba Burman, Ph.D Scholar,Kansas State Univ.,
USA
 Dr. Manas Dhal, R.A., Delhi University
 Mr.Utpaul Bhuyan
 Mr.Dwiban Pujari