Those rivers are located in the North-West of Greece

Voidomatis river:

Its spring is near Vicos village

It ends in Aoos river

Its length is on average 31 km

Aoos river:

Its spring is located in valakalita (Mavrovouni mountain)

The main flow’s length is about 75 km (without taking in account the two tributaries at the spring )

This river continues in Albania

Voidomatis river:

Two main kinds of geological formations

Calcarous rock

Sediment (“alluvions”)

Altitude

The river’s spring is at a high of 950m and joins Aoos river at 600m (0 m is the ocean level)

Aoos river:

Three main kinds of geological formations

•Ultrabasic and basic ophiolitic rocks (diabasic composition)

•Flysch (includes sand and limestone)

•Virgla formation (limestone)

Altitude

The river’s spring is at 800m high and at the Greek border, the altitude is 500m

Voidomatis river:

Sampling sites

The samples have been made just before the river reach Aoos river, at an altitude of on average 600m

Samples

Aoos river:

Here samples have been made near Konitsa at an altitude of 500m

Samples

- The plants samples in the two areas are characteristic of the Riparian vegetation

- The most important factor for the vegetation is the river and not the altitude, so that no furs or pines could be found.

-We generally found the same plant species in the two rivers – except:

In Voidomatis river: Equisetum arvense, Juncus effusus and Corylus avellana

In Aoos river: We have found an algae: Cladophora

- This must not only be related to the river quality since we have made our samples on 50 m on average, and we could have missed other species that were farther.

-Cladophora prefers sheltered areas (without a big current), and is an algae growing in nutrient-rich waters (personal communication). Therefore the presence of this algae indicates that Aoos river is slower flowing with greater nutrient enrichment than Voidomatis where Cladophora was absent.

22

3

1

Profile of the Viodomatis river

1 – In the water

2 – On the edge

3 – On the bankment

23

1

Profile of the Aoos river

1 – In the water

2 – On the edge

3 – On the bankment

In the water (1) On the edge (2) On the bankment (3)

Platanus orientalis Salix fragilis Platanus orientalis

Cladophona Platanus orientalis Salix fragilis

Agrostis Alnus Agrostis stolonifera

Equisetum arvense Berula erecta

Mentha longifola Mentha longifolia

Leucanthemum sp. Clemati flammula

Agrostis sp. Bromus sp.

Salix triandra Calamagostis arundinacea

Corylus sp. Alnus glutinosa

Juncus effusus

Platanus orientalis

Distributed throughout

Platanus o. is mostly found in moist and rich-soil areas

The trees’ roots may be down in the water but despite the fluctuations of water, the plant should not be affected.

Juncus sp. Alnus sp.

All Juncus species are almost always found in wet areas

Alnus has a tolerance to moist soils and grows rapidly

Salix fragilis

Salix is generally found near stretches of water, and is also a riparian plant

Equisetum arvense

It very often forms dense colonies and grows mostly on sand or loam. We have found them near the water but it can also be present inside.

It likes sunny places.

Berula erecta

Calamagostis arundinacea

This herb performs best in rich, well drained soils

It is also a wet land plant that prefers sunny, marshy areas like steam sides

Sampling of benthic invertebrates* The 3-minute kick-sweep method was used in both rivers

* In Voidomatis three samples were taken

* In Aoos river were two samples taken

- Both from the edge to the middle

* Samples collected were stored in bottles and preserved using formalin

-One from the edge to edge

-One from the edge to the middle

-One around the shore

Sorting out the benthic invertebrates

* In the laboratory each sample was sorted separately

* A sieve was used to wash the sample

* The invertebrates were collected in Petri dishes

Identifying the benthic invertebrates

* A stereoscope was used

•Keys were used to determine them to the level of family This because the index calculated (BMWP, Lincoln and the Greek value system) works with families.

0

10

20

30

40

50

60

Bould Cobbl Pebb Grov Silt

AoosVoidomatis

Substrate

Aoos Voidomatis

Conductivity (µ Siemens) 207 252

TDS (mg/l) 106 130

pH 8,43 8.11

DO2 (mg/l) 10,54 11,5

DO (%) 100 98,8

Temp (ºC) 14,1 10,2

Comparison of the physical parameters in the two rivers

3 m 6 m 9 m 12 m 13,5 m0 m

0 m/s0,33 m

0,44 m0,61 m

0,93 m

1,5 m

0,41 m/s

0,77 m/s

0,44 m/s

2,49 m/s

0,44 m/s

Voidomatis river

Physical structure

Discharge (Area*current) 13,95 m3/s

Physical structure of the

Aoos river

Discharge (Area*current) 10,63 m3/s

The use of changes in community structure to monitor pollution commonly involve invertebrates and this group is considered the most appropriate biotic indicators of water quality in E.U. countries (Metcalfe 1989), including Greece (Anagnostopoulou et al,1994). The biotic indices are based on the tolerance of benthic macroinvertebrates or other organisms to low oxygen conditions.

NUMBER OFINDIVIDUALS

GLOSSOSOMATIDAE 190 25.92BRACHYCENTRIDAE 25 3.41

PHRYGANCEIDAE 93 12.69SERICOSTOMATIDAE 48 6.55HYDROPSYCHIDAE 6 0.82

GOERIDAE 11 1.50RHYACOPHILIDAE 1 0.14

LIMNOPHILIDAE 8 1.09BLEPHARICERIDAE 9 1.23

TIPULIDAE 9 1.23ATHERICIDAE 70 9.55

EPHEMERELLIDAE 20 2.73HEPTAGENIIDAE 188 25.65

BAETIDAE 7 0.95OLIGOCHAETA 34 4.64

PERLIDAE 7 0.95NEMOURIDAE 6 0.82

COLEOPTERA DYTISCIDAE 1 0.14TOTAL TOTAL 733 100

ORDERS FAMILIES %

DIPTERA

EPHEMEROPTERA

PLECOPTERA

TRICHOPTERA

PERCENTANGE ABUNDANCE OF BENTHIC INVERTEBRATES.

Sampling sites BMWP GREEK INDEX

LINCOLN INDEX

Across the river 110 6

Excellent

6

Excellent

From the edge to the middle of the river

92 6

Excellent

6

Excellent

Close along the shore

45 5

Excellent

5

Excellent

Mean 82 5.5

Excellent

5.5

Excellent

RESULTS OF VOIDOMATIS RIVER

Piecharts showing the percentage abundance of benthic invertebrates

for 3 samples in the river Voidomatis.

Close along the shore

84.9%

5.5%

6.8%

2.7%

Across the river

29.9%

16.5%

43.0%

10.0%

0.6%

From the edge to the middle of the river

68.2%

8.6%

19.9%

0.0%

3.0%

0.3%

Trichoptera

Diptera

Ephemeroptera

Oligochetae

Plecoptera

Coleoptera

Voidomatis river

51.5%

11.5%

29.2%

5.9%

1.8%

0.1%

Trichoptera

Diptera

Ephemeroptera

Oligochetae

Plecoptera

Coleoptera

Piechart of total percentage of zoobenthos’ presence in the samples

ORDERSFAMILIES

NUMBER OF INDIVIDUALS

%

EPHEMEROPTERA BAETIDAE 23 9.13HEPTAGENIDAE 141 55.95

EPHYMERILLIDAE 15 5.95PLECOPTERA PERLIDAE 5 1.98

LEUCTRIDAE 1 0.40TRICHOPTERA HYDROPSYCHIDAE 57 22.62

HYDROPTILIDAE 7 2.78SERICOSTOMATIDAE 1 0.40

DIPTERA CHIRONOMIDAE 1 0.40LICHOPODIDAE 1 0.40

TOTAL 252 100%

PERCENTANGE ABUNDANCE OF BENTHIC INVERTEBRATES.

SAMPLING SITE

BMWP GREEK INDEX

LINCOLN INDEX

FROM THE EDGE TO THE MIDDLE OF THE RIVER

64 4.5 5.5

RESULTS FROM AOOS RIVER

EPHEMEROPTERA71%

PLEKOPTERA2%

TRICHOPTERA26%

DIPTERA1%

EPHEMEROPTERA

PLEKOPTERA

TRICHOPTERA

DIPTERA

AOOS RIVER: PIECHARTS OF THE ORDERS OF THE BENTHIC INVERTEBRATES

Biotic IndicesAccording to both the Greek and English Biotic Indices used the water

quality of the Voidomatis river is excellent , whereas the Aoos river water quality scores excellent with the English Index and good with the Greek.

The difference in performance of both indices for the Aoos river may be explained by the fact that the English Biotic Index is a qualitative test only and ignores the relative abundance of different groups in the sample. The Greek Index however is both qualitative and accounts for relative abundance and therefore gives a more accurate representation of the water quality based on the invertebrate community structure.

In the Voidomatis river sample, the absence of a difference between the Indices may be related to the very high scores obtained.

Both rivers are located in the National Park of Vikos – Aoos. Voidomatis is in the core of the N.P. where all the human activities are forbidden, whereas Aoos is in the peripheral zone where some activities such as agriculture are allowed.

Because of this one can observe a slightly better water quality in Voidomatis river.

Benthic Invertebrates

The high water quality is reflected in the benthic invertebrates present. In both rivers the greatest percentage of invertebrate families are high scoring in the biotic indices. The lower scoring families contribute only a small percentage of the total families sampled.

The differences in the orders found, e.g. the inverse abundance of Ephemeroptera and Trichoptera between both rivers, is probably related more to sampling error i.e. small sampling sizes, only one station etc. and so chance sampling of concentrated populations of these orders, than to water quality.

However the higher percentage of Trichoptera found in Voidomatis river may be due to the fact that the case bearing families are generally intolerant to moderate enrichment. Also Trichoptera prefer stronger current environment..

In Voidomatis Diptera represent 11.5% of the total sample and in Aoos 1% however no Chironomidae larvae were present. These larvae are usually the most abundant Diptera in aquatic ecosystems, occuring in a wide range of ecological conditions.

The association between filamentous algae and the Chironomidae larvae is often stated in the literature therefore the very low level of these algae in both rivers may explain the absence of Chironomidae.

Physical Parameters

The physical parameters measured during this study are generally of the same range of those recorded in other studies e.g. Bobori et al 1999. This study of the Aliakmon river showed generally the same physical parameter levels and the water quality of this river was scored as excellent/good using biotic indices (M. Lazaridou – Dimitriadou et al 2000).Between the two rivers in this study a negligible difference is observed for pH, DO2 content and percentage, and substrate (small percentage of boulders and silt were present only in Aoos river). The temperature,conductivity and TDS differences observed in both rivers are very difficult to explain but may be attributed to the higher discharge recorded in Voidomatis river. Larger discharge may be due to the inclination of this river from source (900m altitude ) to sample site which was greater than in Aoos river and also there was a greater depth (at the sample site) in Voidomatis river.

Sampling problems• Sampling was carried out at only one station with no spatial or temporal

repetition.One random sample may by chance target a large population of one species and so distort the results.

• Sampling should be carried out by just one individual otherwise, with the three minute kick method, different kicking technique and strength may (the effort) effect the size and quality of the sample taken.

• The number and position of the samples taken was not consistent for both rivers and so is not comparable. For example the time may not have been 3 minutes in Aoos river because it was very difficult to walk in the river and a lot of time were lost. Also sampling time for Voidomatis river was 9 minutes, whereas Aoos river was sampled only for 6 minutes.

• No attempt was made to measure chemical parameters ( nutrients, nitrogen, phosphorus etc). The application of biotic indices provides a more integrated result concerning water pollution when combined with measurements of physical and chemical parameters.

• Lack of specialist knowledge about the ecology and biology of macroinvertebrates with in the study group

-http://www.ellada.com

-Photos of rivers: Kapfer Geraldine

-http://www.wisc.edu/botit/img/bot/401/

-Drawing : Schneider Christine

-http://www.terra.ecol.ktle.hu/haznod/htm/Calamagrostis arundinacea.htm

-http://www.euronet.nl/users/mbleeker/folis/bsmain-e.html

- D.C. Bobori & S.D. Mourelatos – Physical parameters and nutrient content of the surface waters of the river Aliakmon (Greece) – Editors Freising-Weihenstephan/FRG, 1999

-M. Anagnostopoulou – The relationship between the macroinvertebrate community and water quality, and the applicability of biotic indices in the river Almopeos system (Greece), University of Manchester, 1992

-R. Wellinghorst – Wirbellose Tiere des Susswasser, Friedrich Verlag, Seetze, 1993

-http://www.apr.ethz.ch/CD-ROM/Familien/Equicetaceae/Equisetum

-http://www.terra.hu/haznod/jpg/Calamagrostis.arundinacea.1.html

-http://www.puc.edu/Faculty/Gilbert_Muth/Berula#erecta

This presentation on Voidomatis and Aoos rivers has been made with the cooperation of all the following European students:

Stevenson Joan Bousiaki Elena

Patoux Clothilde Sarris Marcos

Schneider Christine Nordstrom Kerstin

Nehrwein Birgit Svensson Jessica

Kapfer Geraldine Ringsbo Jens

von Schantz Mattias Francis Nikki