INVERTEBRATES ASSOCIATED WITH MYRIOPHYLLUM SPICATUM L. IN SAKADAŠ
LAKE WITHIN KOPAČKI RIT FLOODPLAIN, CROATIA
Dubravka Čerba, Irella Bogut, Jasna Vidaković and Goran Palijan
Department of Biology, University of J. J. Strossmayer, Trg Ljudevita Gaja 6, HR-31000 Osijek,
Croatia; e-mail: dcerba@vip.hr ibogut@ffos.hr javidako@inet.hr gpalijan@ffos.hr
Sampling of invertebrates associated with submersed macrophyte species Myriophyllum spicatum L.,
was conducted once a week during July, August and September 2004, at three sites, noted as I, II and
III, in Sakadaš lake within Kopački rit floodplain in the North-East Croatia (Figures 1a and 1b).
II
I
Čonakut Channel
area of Kopački rit
III
Novi Channel
Sakadaš lake
Figure 1b. Research sites in Sakadaš lake
Figure 1a. Eastern part of Croatia
The weather and environmental parameters were as expected for summer season: high air
temperatures, little rain, what influenced water temperature as well as decrease in depth and
transparency (Table 1).
Table 1. Mean values of environmental parameters during research period in 2004 in Sakadaš lake
Environmental
14.7.
21.7.
28.7.
4.8.
12.8.
18.8.
25.8.
1.9.
parameters
8.9.
water temp. ( °C)
23.7
27
23.8
24.8
25.3
24
23
22.5
21.2
depth (m)
2.8
2.4
1.3
1.4
0.8
0.5
0.5
0.9
0.6
SD (m)
1.2
1.1
0.8
0.6
0.6
0.4
0.5
0.6
0.5
O2 (mgl-1)
3.9
4.7
3.9
7.9
9.7
8.2
12.2
9.1
10.1
chl-a (µgl-1)
28.9
11.4
38.4
30.5
40.8
44.6
45.2
52.9
48.5
T-P (mgl-1)
0.1
0.1
0.2
0.1
0.1
0.1
0.1
0.5
0.04
There was a statistical significance in difference between environmental parameters recorded in July
and those recorded in August (R=0.647, p<0.001) and September (R=0.739, p<0.001) (Figure 2), but
there was no statistically important difference between sites for environmental parameters.
Stress: 0,05
JULY
AUGUST
SEPTEMBER
Figure 2. NMDS plot of environmental parameters recorded at the research sites
Calculated TSI values (Carlson and Simpson, 1996), based on concentration of chlorophyll-a and
amount of T-P, indicated states of eutrophy and hypertrophy, for some dates, what is analogue to
results gathered during reseach conducted from 1997 to 2004 (Vidaković et al., 2002; Bogut et al.,
2003).
Myriophyllum spicatum first appeared in Sakadaš lake in the year 2004 and then the research on
phytophilous invertebrate fauna began. In collected fauna we recorded 23 taxonomic groups and they
are presented by their abundance as number of individuals per 100 g plant dry weight (Table 2).
Table 2. Mean invertebrate abundances (ind. 100 g-1 d.w.) at sites during research period
sites
I
II
III
Zygoptera
167.5
156.8
61.8
Anisoptera
0
0
3.4
Chironomidae
6743
7572.4
2891.2
Hemiptera
23.1
0
0
Ephemeroptera
56.6
44.4
12.2
Ceratopogonidae
8.4
101.9
39.4
Plecoptera
4.2
0
0.7
Trichoptera
0
5.2
0
Heteroptera
0
3.1
0
Muscidae
0
0
0.7
Dytiscidae
0
0
0.7
Oligochaeta
104.9
243.4
1740.5
Cladocera
182.3
148.4
314.6
Nematoda
75.4
92.9
2435.4
Copepoda
213.7
32
61.1
Nauplii
69.2
136.2
199
Insecta
23
3.1
4.1
Turbellaria
8.4
97
76.9
Gastropoda
6.3
20.6
6.1
Hydrozoa
2.1
2.1
12.9
Bivalvia
0
0
1.4
Hirudinea
2.1
0
0
Hydracarina
2.1
0
0
total
S
54000.8
17
62587.2
15
43458
18
Dominance in recorded invertebrate fauna had Insecta larvae (representatives of Zygoptera,
Anisoptera, Chironomidae, Hemiptera, Ephemeroptera, Ceratopogonidae, Plecoptera, Trichoptera,
Heteroptera, Dytiscidae and Muscidae), with the percentage rate ranging from 42% to 90% of total
fauna at the research sites (Figure 3).
100%
others
80%
Nematoda
60%
Oligochaeta
Insecta larvae
40%
20%
0%
SIT E I
SIT E II
SIT E III
Figure 3. Percentage rate of invertebrates at each site
The
highest
abundance
(47258.9
individuals per 100 g of M. spicatum dry
weight at the site I, 53886.4 ind. 100 g-1
d.w. at the site II and 17739.9 ind. 100 g-1
d.w. at the site III) was found for members
of the family Chironomidae (Table 2),
what is 71% of all invertebrates at all three
sites. At the site III high densities had
Nematoda with 12086.3 ind. 100 g-1 d.w.
and Oligochaeta with 9235 ind. 100 g-1
d.w, what representes 28% and 21% of all
invertebrates at that site (Figure 3).
Very successful invertebrates, present in high abundance in eutrophic waters are Chironomidae larvae
(Lund, 2001) and Oligochaeta (Mackie, 2001). Predominance of Chironomidae larvae is usual in
eutrophic waters associated with macrophytes (Soszka, 1975; Linhart, 1999). According to the nonmetric multidimensional scaling, NMDS, and analysis of similarities, ANOSIM, statistically
significant difference exists in invertebrate abundances between the site I and the site III (R = 0.772, p
< 0.005), as well as between the site II and the site III (R = 0.514, p < 0.01) (Figure 4).
Stress: 0,09
SITE I
SITE II
SITE III
Figure 4. NMDS plot showing difference in invertebrate abundances between the research sites
Also, there is statistically significant difference between months of sampling: July and August
(R=0.647, p<0.001) and also July and September (R=0.739, p<0.001), regarding fauna
abundance (Figure 5).
Stress: 0,09
JULY
AUGUST
SEPTEMBER
Figure 5. NMDS plot showing difference in invertebrate abundances between months
Statistically significant correlation (p<0.02) was found between invertebrate number and M. spicatum
dry weight at the site III. These results could be explained by the fact that the M. spicatum stand at the
site III lasted continuously over the whole sampling period, while the stands at the sites I and II did no
longer exist after the first half of August 2004.
References:
Bogut I, Vidaković J, Palijan G. 2003. Trophic state and water quality in Kopački rit during 2002. In: 3 rd
Croatian Confrence on Waters, Croatian Waters in the 21 st Century. p 173-179.
Carlson RE, Simpson J. 1996. A Coordinator’s Guide to Volunteer Lake Monitoring Methods. North American
Lake Management Society. 96 p.
Linhart J. 1999. Phytophilous macrofauna in the Stratiotes aloides vegetation of the Lake Łukie, Poland. Acta
Univ Palacki Olomuc, Fac rer nat, Biol 37:67-76
Lund MA. 2001. Nuisance midge (Chironomidae) plagues in urban wetlands: A catalyst for improved catchment
management In: Proceedings of the 28th National Environmental Health Conference (CD-Rom), Australian
Institute of Environmental Health, 14th-19th October 2001 Perth.
Mackie GL. 2001. Applied Aquatic Ecosystem Concepts. Kendall/Hunt Publishing Company. 744 p.
Soszka GJ. 1975. The invertebrates on submersed macrophytes in three Masurian lakes. Ekol Pol 23: 271-391.
Vidaković J, Bogut I, Borić E, Zahirović Ž. 2002. Hydrobiological research in the Kopački rit Nature Park in the
period November 1997 – October 2001. Hrvat Vode 10(39):127-144.