NEMATODE COMMUNITIES AS NEMATODE COMMUNITIES AS BIOINDICATORS OF BIOINDICATORS OF ANTROPOGENIC INFLUENCE IN ANTROPOGENIC INFLUENCE IN AGROECOSYSTEMSAGROECOSYSTEMS
Mirjana BRMEZ, Marija IVEZIC, Emilija RASPUDIC, Vesna TRIPAR, Renata BALICEVIC
University of J.J. Strossmayer in Osijek, Faculty of Agriculture in Osijek, Croatia
Nematodes as Nematodes as bioindicatorsbioindicators
– they occur in almost every habitat (terrestrial, aquatic and marine),
– they occure with many species per sample or habitat,
– they respond quickly to environmental changes,
– they show specific respond to various types of pollution or disturbances,
– they are in close contact with dissolved compounds in free soil water,
Nematodes as Nematodes as bioindicatorsbioindicators
– they are easily sampled and extacted from the soil,
– the sampling can be done in any time of the year,
– storage of the samples requires little space– Analyses of nematode community
structure can be related to feeding types (trophic group), c-p groups from 1-5, absolute abundances, number of genera, Maturity index, Plant parasitic index etc.
““PersistersPersisters””- long life-cyclelong life-cycle- sensitive to sensitive to
disturbancesdisturbances- low reproduction ratelow reproduction rate- they hardly fluctuate they hardly fluctuate
in number over the in number over the yearyear
- never belong to never belong to dominant species in dominant species in the samplethe sample
- have few small have few small gonads, and produced gonads, and produced large eggslarge eggs
““ColonizersColonizers””- short life cycleshort life cycle- tolerance to tolerance to
disturbancesdisturbances- high reproductive ratehigh reproductive rate- high colonization high colonization
abilityability- have voluminous have voluminous
gonads, gonads, - release large numbers release large numbers
of small eggs, and of small eggs, and are often viviparousare often viviparous
C-p groups (1-5)C-p groups (1-5)
Maturity index Maturity index (Bongers, 1990)(Bongers, 1990)
v(i) – (c-p) v(i) – (c-p) value assigned to familyvalue assigned to family ((i) f(i) - f(i) - the frequency of family (the frequency of family (i) in a in a
samplesample
Lower index reflect disturbanceLower index reflect disturbance
if
ifivMI
AimAim
The objective of this investigation The objective of this investigation was to determine if the nematode was to determine if the nematode communities in the soil could communities in the soil could serve as bioindicators of serve as bioindicators of anthropogenic activities in anthropogenic activities in agroecosystems. agroecosystems.
MATERIAL AND METHODSMATERIAL AND METHODS
TREATMENTS:TREATMENTS:– Poplar forest,– Arable land with standard tillage
regimes – wheat, – Arable land with standard tillage
regimes – corn. Sampling: in spring period 2001, in Sampling: in spring period 2001, in
the 4 replicates, using sonda the 4 replicates, using sonda ØØ 2 2 cm, on the depth of 20 cmcm, on the depth of 20 cm
MATERIAL AND METHODSMATERIAL AND METHODS
• Extaction of of nematodes – 100 nematodes – 100 g of soil - g of soil - Seinhorst method Seinhorst method (1956)(1956)
• Identification – genus level
RESULTSRESULTSTotal number of nematodes and number of genera
0
500
1000
1500
2000
2500
3000
poplar wheat corn
No.
of n
emat
odes
in
100
ml o
f soi
l
0
5
10
15
20
25
num
ber
of g
ener
a
total no. of nematodes number of genera
Trophic structure
0
10
20
30
40
50
60
poplar wheat corn
Bacterial feeders Fungal feeders Omnivorous Predators Plant feeders
%
RESULTS
Tretments
AverageMI
Average PPI
Average PPI/MI
AverageTotal no.
nematodes
Average no.
genera
poplar 1,95 2,40 1,27 1386 20,25
wheat 1,72 2,58 1,50 1922 17,25
corn 1,57 2,83 1,83 2456 14,50
Lsd 0,05 n.s. n.s. 0,3751 n.s. 3,4758
Lsd 0,01 n.s. n.s. n.s. n.s. n.s.
RESULTS
On the base of this investigations we can conclude that nematode communities could serve as a very bood bioindicator of antropogenic influence in agroecosystem.
CONCLUSIONCONCLUSION
AcknowledgAcknowledgeementment
The investigations are suported The investigations are suported by the Ministry of Science and by the Ministry of Science and Technology in Croatia (Project- Technology in Croatia (Project- 079024).079024).