Distribution of macrophytes in different water-bodies (habitats)

influenced by the Gabcíkovo hydropower station (Slovakia) – present

status

Helena Othelová1 and Milan Valachovič2

With 10 figures and 1 table in the text

Abstract: The distribution of macrophytes in the Slovak reach of Danube is presented in

three types of water bodies with different environments and management regimes: i) The

Old Danube River (1839-1811 km), ii) the anabranch system iii), the seepage canal. The

succession and content of aquatic plants changed depending on hydrological regime. The

succession of macrophytes started in the Old Danube. Zannichellia palustris is the first

hydrophyte that overgrows the river bed, which is covered by a thin layer of fine sediment.

Temporary denuded pools on flat littoral zone provided favourable conditions for

succession. The semi-natural anabranch system supported high biodiversity, where 24

species in three backwaters were recorded. Also the new artificial habitat of the seepage

canal is species rich. Some of the rare and endangered species, such as Groenlandia densa,

Hippuris vulgaris, Apium repens and Characeae found suitable habitats here. The

distribution of neophyte, Elodea nuttallii increased rapidly in the Slovak part of Danube

flood plain.

1 Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 14, SK-842 23 Bratislava, Slovakia, botuhela@savba.sk. 2 Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 14, SK-842 23 Bratislava, Slovakia, botumiva@savba.sk

Introduction

Different aspects of the aquatic vegetation of the Danube flood plain were studied in

Slovakia . HEJNÝ (1960) provided a reputable source of information about auto-ecology

of aquatic and marsh plants and their localities. Phyto-sociological evaluations of aquatic

vegetation by Braun-Blanquet method were performed later by OTAHELOVÁ (1978, 1980),

OTAHELOVÁ, HUSÁK (1992), and ADAMEC et al. (1993), the latter also complemented with

ecophysiological studies. In recent years more papers relating to endangered species

appeared (OHRÁDKOVÁ 1998, OTAHELOVÁ 1998, OTAHELOVÁ, BANÁSOVÁ 1997).

However, detailed data of the spatial and temporal distribution macrophytes are absent.

These are very important, especially for the monitoring of changes caused by human

impact.

Construction of the Gabcíkovo hydropower station altered the hydrological regime

causing changes in the distribution of macrophytes, as well as in the vegetation along both

banks (RATH 1997, ŠOMŠÁK 1999). The aim of this study was to map the present

distribution of macrophytes along fixed sections and to prepare the foundations for future

monitoring. Quantitative values for macrophytes were compared with abiotic data and

some relationships between the distribution of plants and ecological factors were

observed.

Study area (Fig. 1)

The Slovak part of the Danube River is 172 km long. The mean discharge in Bratislava is

2,000 m3.s-1, the maximum and minimum flow rates are above 10.000 m3 s-1 and 570 m3 s-1

respectively. The most important tributaries are the Morava (March), Váh, Nitra, Hron and

Ipel (Ipoly).

The Danube flows through the Little Carpathians at the Devín Gate into the Danube

lowland (Podunajská nížina). The lowland relief characteristics typical of the fluvial plain

and lies between altitudes of 106 to 128 metres above sea level. This flattening of the

Danube’s gradient caused extensive aggradiation of a large amount of gravel and sand and

creation of a massive fluvial fan (flood plain) between Bratislava and Komárno during the

Quaternary period. The flood plain along the Danube represents a unique continental delta,

system of meanders and dead branches, a so-called "Inland delta”.

The territory has the warmest and driest climate of Slovakia (mean January temperatures

from -1 to -4 °C, July temperatures from 18.5 to 20.5 °C and the mean annual precipitation

from 0.55 to 0.6 m. The natural course of the Danube River in Slovakia has been strongly

influenced by human activities for two centuries. Since the early eighteenth century, free

meandering of the river was gradually limited by construction of the dykes. Thus, the wide

floodplain with its network of branches was reduced to a relatively narrow strip varying in

width from three to five kilometersm.

In the 1980´s work was started on the construction of the Gabcíkovo hydroelectric water

system which was completed in 1993. Diversion of the main stream into the bypass canal

began in October 1992. Presently, a discharge between 200 to 400 m3 s-1 is permanently

released through the weir in the Old Danube at river km 1851.7, where the Danube was

dammed. Compared with the original project, the mean monthly discharge (CHALUPKA

1998) was decreased about 83 %. The decreased flow caused succession of the macrophyte

vegetation in the Danube bed (ŠOMŠÁK 1999).

A semi-natural anabranch system surrounded by alluvial forest was preserved on the new

island between the Old Danube and the bypass canal. Owing to different management

regimes there are two distinguishable parts (sections) of this system.

The upper and middle part of the anabranch system on the left bank of the Old Danube

(Dobrohošt-Gabcíkovo section) has been fed with water from the bypass canal through a

special inlet structure since May 1993. The maximum capacity of the structure is 240 m3 s-

1, which makes it possible to simulate flood conditions in this system. The discharge of 30

m3 s-1 maintains water levels and moisture conditions in this region during the period of

vegetative growth. To improve the water balance and the distribution of flows throughout

the anabranches, cascades were rebuilt. Culverts and broad-crested weirs ensure flow

continuity and control water levels. To prevent the water from being lost to the Old

Danube, all contact points are blocked except the confluence of the main branch and the

river near Gabcíkovo. Thus water levels in the anabranches are presently higher than in

Old Danube (LISICKÝ & HOLUBOVÁ 1999). In case of the main branch, current speed

increased and the relationship between the drift, sedimentation and erosion changed. The

water level rose and the width of the arms increased. The banks became longer and less

straight and new pools with stagnant water appeared in depressions. The old main channel

of the Danube started to meander within the original riverbanks and the weirs provided

greater variability in water current. Since then, water level fluctuation has become

relatively low, with the exception of controlled flooding (KRNO et al. 1999). Relatively

good quality forest, with low defoliation, stands in the river branch system area between

Dobrohošt and Gabcíkovo which was controlled by supplying water to the within-dike

zone. The direct flooding has been manifested in the herbaceous vegetation by the

substitution of mesophilous and nitrophilous species by more hygrophilous and less

nitrophilous species (UHERCÍKOVÁ et al. 1999).

In the lower part of the anabranch system (Gabcíkovo-Sap section) the arms are not

artificially fed by water and are strongly influenced by the backward movement of water

from the confluence of the old river bed with the bypass canal (VRANOVSKÝ & ILLYOVÁ,

1999). The discharge rate varies and follows the pattern of the discharge rate at

Bratislava, and is also partially dependent s on the operation of the turbines (water level

fluctuation ca 0.5 m). Consequently, silt sedimentation has increased in this area and the

water level is slightly lower (KRNO et al. 1999). The area of the backwater represents

ideal conditions for the natural regeneration (successive development) of the willow

poplar communities (Salici-Populetum typicum, phragmito-caricetosum and

myosotidetosum) (ŠOMŠÁK 1999).

Canals are a new type of artificial aquatic habitat. On both banks of the bypass canal

seepage canals were built between July 1979 to May 1992. The researched seepage

canal is located on the right side of the bypass canal. Its total length is ca 20 km. It

follows its headwater section from Dobrohošt to the Gabcíkovo hydropower station,

where discharges into the tailrace section of bypass canal. The canal is fed by seepage

water from the Cunovo reservoir and the bypass canal. In times of high water in the

Danube, the water of the tailrace section of the bypass canal is released to the seepage

canal and it reached as far as Bodíky village. The lower sections of the canal gradually

reach widths between 2 and 7 m. The depth varies from 0.5 m to 6 m and the discharge

from 0.3 to 4 m3 s-1. The gradient of bed is 0.03-0.5%. A system of eight weirs controls

the water level. The bank is covered by the geo-textile, a 0.3 m thick coat of gravel-sand,

and by 0.2 m coat of humus.

The Danube floodplain in Slovakia has been protected since 1998 under the Act of the

National Council No. 287/1994 on Nature and Landscape Protection as a Protected

Landscape Area (PLA). This level of protection corresponds with Category V of the IUCN

classification. The upper part of the Žitný ostrov Island was declared a protected water

management area in 1978.

Material and Methods

A standardized method including field estimation as well as the data processing and

display methods was used for the evaluation of aquatic vegetation (KOHLER & JANAUER

1995). Aspects of dominance and characteristic types of hydrophyte distribution are

discussed by the use of numerical derivatives: distribution diagrams, relative plant mass

(RPM), means mass index (MMO, MMT) and a distribution ratio (d). Three types of

habitats influenced by construction of the Gabcíkovo hydropower complex were chosen

for the testing of the response to the water regime changes (Fig. 1):

1. The old main channel of the Danube River, now called ”Old Danube”- the Slovak side

lies between 1839 and 1811 river-kilometres. Length of the surveyed stretches was always

1 km in main channel. Length of stretches of another habitats depended on the vegetation

and environment. Numbering of stretches: 1-40. Date of survey: August 17-18, 1999.

2. Three ecologically different side arms in anabranch system on the left bank of the Old

Danube were surveyed from July to August 1999:

• Bodícka brána backwater - a parapotamon type of side arm, located in the Dobrohošť –

Gabcíkovo section. No. of stretches: 41-48.

• Královská lúka backwater- a plesiopotamon type of side arm, located in Dobrohošt –

Gabcíkovo section. No. of stretches: 49-52.

• Dedinský ostrov backwater – a parapotamon type of side arm, located in Gabcíkovo –

Sap section. No. of stretches 53-58.

3. The seepage canal on the right bank of the bypass canal. No. of stretches: 59-93. Date of

survey: July-August 1999.

All stretches were located by GPS and delineated onto a 1:25 000 scale map. For precise

location aerial photographs were used.

Results

A total of 42 species (36 vascular plants, 2 bryophytes, 4 algae) were found in the Danube

River and its flood plain area between 1839 and 1811 river kilometres (Table 1).

Old Danube River

Species List (Table 1, column 1)

The main channel of the Old Danube contained 18 species (17 vascular plants, 1

bryophyte).

Distribution Diagram (Figure 2)

The number of species in 40 stretches of 28 river kilometres of the main river channel and

12 pools on the left bank ranged between 0 and 10. The main channel was relatively poor

in terms of the number of species, predominantly 1(-2) species per kilometre. The upper

half of surveyed main channel had contiguous growth, but varying amount of Zannichellia

palustris. In the adjacent pools, an average of 4 species was recorded (max. 10), mostly

comprised of Elodea nuttallii, Potamogeton species, and Ceratophyllum demersum.

Relative Plant Mass (Figure3)

Submerged rhizophytes were the major growth form in the Old Danube River with

Z. palustris being by far the dominant species.

Mean mass Index and Distribution Ratio (Figure 4)

Potamogeton perfoliatus reached an MMO near 4 and Najas marina 3, but both have very

low MMT values and are absent from most of the length of the watercourse, indicating

their clumped distribution in Old Danube. Associated species had MMO values below 3.

Truly ubiquitous species were not found in any stretches with the exception of

Zannichellia palustris which attained a “d” value close to 0.5, whereas in all species “d”

values are below 0.2.

Anabranch system

Species List (Table 1, Column 2)

A total of 24 species (22 vascular plants, 1 bryophyte, 1 algae) was found in the three

backwaters surveyed.

Distribution diagram (Figure 5)

The three water-bodies were divided into 18 stretches and the accumulated length of the

survey stretches was ca 5.5 km. The length of relatively uniform survey stretches ranged

from 25 to 1000 m. The number of species varied from 4 to 11. With the exception of the

Královská lúka backwater, a long part of the arms had contiguous growth, but with

varying amounts of Elodea nuttallii. Its invasive distribution during previous years

especially in parapotamon tip of side arms was evident.

Relative Plant Mass (Figure 6)

Elodea nuttallii was the dominant hydrophyte. Subdominant species were Ceratophyllum

demersum, Potamogeton crispus and Myriohyllum spicatum with RPM value between

10-20 %.

Mean Mass index and Distribution Ratio (Figure 7)

The most abundant and ubiquitous species were E. nuttallii and Ceratophyllum demersum

in contrast to Salvinia natans and Nymphaea alba which had “clumped” distributions.

Seepage canal

Species list (Table 1, column 3)

25 species were recorded in this watercourse (Table 1). The majority of species were

common in the adjacent water bodies, but some currently occurred only here.

Distribution Diagram (Fig. 8)

The 19.8 km total length of the seepage canal was divided to 34 uniform stretches by

varying in length from 30 to 2100 m. The shortest stretches were usually in the weirs of

the section. The length of the majority of stretches varied from 300 to 800 m.

Relative Plant Mass (Figure 9)

Submerged rhizophytes were by far the dominant growth form. Only two stoneworts

Chara foetida and Ch. hispida reached RPM values between 10 and 20 %. RPM of other

species was less than 8%.

Mean Mass Index and Distribution Ratio (Figure 10)

Chara hispida, Ch. foetida, and Elodea canadensis reached the MMO values between 4

and 5. The distribution of Ch.hispida and Ch. foetida is middle-clumped. No truly

ubiquitous species were recorded, but 11 species had “d” values ca 0.5.

Discussion

The new hydrological regime of Danube River manifested itself in the succession of

plants in riverbed. From the point of view of the distribution of the macrophytes in Old

Danube it is possible to distinguish three reaches:

Theupper reaches impound (1839-1831 km) - In the main river channel only

Zannichellia palustris occurred most regularly. Elodea nuttallii was recorded here in only

one stretch of the main channel (1836 km) but the occurrence extends to the adjacent

oxbow. In the oxbow Ceratophyllum demersum and Z. palustris also grow. There are

also several semi-separated oxbows where Z. palustris occurred.

The middle reaches (1830-1820 km) - with the highest relative diversity of plant species

and habitats (anabranch system). Z. palustris continued to be dominant in the main

channel. Sporadic growths ofCeratophyllum demersum, Elodea nuttallii, and Ranunculus

trichophyllus occurred and created common communities in neighbouring oxbows.

Oxbows were relatively rich in macrophytes. The neophyte Elodea nuttallii dominated

but other species such as Zannichellia palustris, Potamogeton crispus P. pusillus, P.

pectinatus, Lemna minor and Myriophyllum spicatum were frequently present and in

varying amounts.

The lower reaches (1820-1811 km) -in these reaches the water level fluctuates, as they

are situated near the confluence with the new bypass canal. This influence is reflected in

the species composition. In left river bed Polygonum amphibium, Butomus umbellatus,

and Rorippa amphibia were recorded.These plants adapt to water level changes as

hydro-, limosal and terrestrial ecophases. Typical hydrophytes such as Elodea nuttallii

and Myriophyllum spicatum were sparse in the lower reaches. Mosses were found only in

one stretch (1813 rkm), within the Phragmites australis community. Cinclidotus riparius

(syn. C. nigricans) specifically and other common species of the Danube bank (cf. PIŠÚT

1981) were recorded in 2000 in 1811 km on a gravel deposit at the confluence with

bypass canal. Zannichellia palustris is typically absent from these lower reaches,

probably as a result of the high turbidity of the water. The last three kilometres near the

confluence of the Old Danube and new bypass canal were devoid of vascular plants.

RATH (1997) recorded a similar floristic spectrum while surveying the right bank

(Hungarian part) of the main channel of the Danube in stretches between 1826 and 1843

rkm in 1996. She recorded practically the same species structure (16 species) in similar

habitats. The frequency of Z. palustris and Elodea nuttallii has increased slightly over the

past three years.

The first hydrophyte, which overgrows riverbed of Danube River, is Zannichellia

palustris. During 1999 it had the highest distribution in the stretches surveyed. It created

a very low, thin carpet on the riverbed from 1838 to 1821 river kilometres, which is its

typical growth form in running waters. Z. palustris occupied stretches with low flow and

fine inorganic sediment. It was recorded also in adjacent oxbows where light conditions

were favourable. Relatively the most suitable conditions for succession of macrophytes

are on the flat littoral of the Old Danube along with the numerous oxbows and temporary,

denuded pools. Elodea nuttallii frequently occurs alongside Z. palustris. Najas marina,

Potamogeton species, and lemnids are rich in water-bodies located in areas influenced by

human activities, such as recreational facilities.

The semi-natural anabranch system maintained high biodiversity. In three backwaters

the number of species varied from 12 to 17. However, the localities were chosen in

various areas with different ecological properties. Five common species (Ceratophyllum

demersum, Spirodela polyrhiza, Lemna minor, Ranunculus circinatus and Najas marina)

were recorded in varying amounts.

In both arms of the parapotamon type, which are fed by water from the bypass canal,

species adapted to flowing water such as Butomus umbellatus var. vallisneriifolia,

Potamogeton perfoliatus, P. crispus, and Myriophyllum spicatum grow. The invasive

distribution of E. nuttallii during recent years is evident.

In Královská lúka - plesiopotamon-type of side arm, pleustophytes such as

Ceratophyllum demersum, Hydrocharis morsus-ranae, and Salvinia natans dominated.

Fine silt sediment in both backwaters (Dedinský ostrov and Královská lúka) allowed

colonisation of Nymphaea alba and Nuphar lutea.

In spite of their relatively young age, fluctuating water regime and intensive human

activity in the seepage canal, a high diversity of plant species was observed. 25 species

(21 vascular plants, 4 algae) were recorded and the cover of the stand usually varied from

50 to 80%. Despite their intensive and variable management there is a dependence on the

distribution of macrophytes in this environment. The pleustophyte Utricularia vulgaris

occupied only the most upper reaches, in stagnant water ca 1m deep. Conversely, in the

lower reaches with deeper water and fluctuating levels, species morphologically adapted

to these conditions usually grow. Sparganium emersum, Myosotis palustris, and Apium

repens create submerged forms. The heterogeneous ecological conditions of the seepage

canal with its neighbouring natural and semi-natural aquatic habitats allows colonisation

by ubiquitous and also rare species such as Apium repens, Groenlandia densa and

Hippuris vulgaris, which are registered in the Red Book of Slovakia (OVSKÝ et al. 1999).

In almost all stretches of the seepage canal various species of Characeae ( including

Chara foetida, Ch. fragilis, and Ch. hispida ) were found.

The invasive neophyte Elodea nuttallii, which was recorded in the Danube Inland delta

for the first time only in the last ten-years (RATH 1992, OTAHELOVÁ 1996) has rapidly

increased.

Acknowledgements

The authors are greatly indebted to Z. Bankó (Bratislava) for carrying out the field

investigations, K. Pall (Vienna) for the diagrams and J. Ripka (Bratislava) for preparation

of the map. ArcGeo (Bratislava) developed the basic map.

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Tables:

Table 1

Total list of species in Inland delta of the Danube River (Slovakia)

Figure Captions:

Fig. 1.: Map of surveyed area –Slovak part of the Inland delta of the Danube River. Number

of stretches (Sampling sites) 1-93.

Fig. 2: Distribution Diagram of macrophytes / Old Danube

Fig. 3: Relative Plant Mass / Old Danube

Fig. 4: Mean mass Index and Distribution Ratio/ Old Danube

Fig. 5: Distribution Diagram of macrophytes / Anabranch system

Fig. 6: Relative Plant Mass / Backwaters

Fig. 7: Mean mass Index and Distribution Ratio / Backwaters

Fig. 8: Distribution Diagram of macrophytes / Seepage canal

Fig. 9: Relative Plant Mass / Seepage canal

Fig. 10: Mean mass Index and Distribution Ratio / Seepage canal

Table 1. TOTAL LIST OF SPECIES (1 Old Danube R., 2 Anabranchsystem, 3 Seepage canal )Locality 1 2 3No of survey stretch in map 1- 41- 59-

40 58 93

VASCULAR PLANTS Abbr. GF*Apium repens (Jacq.) Lag. Api rep saButomus umbellatus L. But umb saCallitriche cophocarpa Sendtn. Cal cop saCallitriche sp. Cal spe saCeratophyllum demersum L. Cer dem spEleocharis acicularis (L.) Roem. et Schult. Ele aci saElodea canadensis Michx. Elo can saElodea nuttallii (Panch.) H. St. John Elo nut saGroenlandia densa (L.) Fourr. Gro den saHippuris vulgaris L. Hip vul saHydrocharis morsus-ranae L. Hyd mor apLemna minor L. Lem min apLemna trisulca L. Lem tri spMentha aquatica L. Men aqu saMyosotis palustris ag. Myo pal saMyriophyllum spicatum L. Myr spi saMyriophyllum verticillatum L. Myr ver saNajas marina L. Naj mar saNuphar lutea (L.) Sm. Nup lut flNymphaea alba L. Nym alb flPolygonum amphibium L. Pol amp flPotamogeton crispus L. Pot cri saPotamogeton lucens L. Pot luc saPotamogeton nodosus Poir. Pot nod flPotamogeton pectinatus L. Pot pec saPotamogeton perfoliatus L. Pot per saPotamogeton pusillus agg. Pot pus saRanunculus circinatus Sibth.. Ran cir saRanunculus trichophyllus Chaix Ran tri saRorippa amphibia (L.) Besser Ror amp flSalvinia natans (L.) All. Sal nat apSparganium emersum Rehrmann Spa eme flSpirodela polyrhiza (L.) Schleid. Spi pol apTrapa natans L. Tra nat flUtricularia vulgaris L. Utr vul spZannichellia palustris L. Zan pal saNON-VASCULAR PLANTSAlge filamentosaea Alg fil spChara foetida A. Braun Cha foe saChara fragilis Desv. Cha fra saChara hispida L. Cha his saBryophyt sp. ??? saRiccia fluitans L. emend Lorb. Ric flu sp

Number od species 42 18 24 25

*ap - acropleustophytes, sp - submerged pleustophytes, sa-submerged anchoredmacrophytes, fl-floating leaf rhizophytes

1 = Old Danube2 = Anabranch System3 = Seepage canal

Fig. 21 2 4 5 6 7 8 9 10 14a 18 19 20 30 37 79 81 83 86 8824 26a 26 77

Fon antAlg filRhy ripSpa ereSpa emePer hydAgr stoCal palChi palFis adiLem minMyo scoVer becCar speRan aquPot criPha aruAli lanGly fluTyp latGly maxBut umb

Ver ana

Lee oryRum speLyc eurSta pal

Fig. 3

Fig. 3

0

10

20

30

40

50

60

70

80

90

100

Zan

pal

Elo

nut

Pot p

er

Pot p

us

Ror

am

p

Naj

mar

Pot c

ri

Pot p

ec

Ran

tri

Cer

dem

Pol a

mp

resi

dual

RPM

(%

Fig. 4

1 - 40

1 2 3 4 5MMT, MMO

Zan pal

Bryophyt

Pot pus

Ran tri

Ror amp

Spi pol

Pot cri

Pot luc

Pot pec

Pot per

Lem min

Myr spi

Naj mar

Pol amp

But umb

Cal spe

Cer dem

Elo nut

0 0,5 1d

Fig. 5 strech 41 42 45 46 47 48 50

But umb

Cer dem

Elo nut

Hyd mor

Pol amp

Pot cri

Lem min

Lem tri

Myr spi

Naj mar

Alg fil

Ran cir

Ran tri

Ror amp

Sal nat

57

Spi pol

Ric flu

Tra nat

Pot luc

Pot nod

Pot pec

Pot per

Nup lut

Nym alb

Fig. 6

Fig. 6

0

10

20

30

40

50

60

70

80

90

100

Elo

nut

Cer

dem

Pot p

er

Myr

spi

Ran

tri

But u

mb

Nym

alb

Spi p

ol

Lem

min

Ran

cir

Pot n

od

Nup

lut

Naj

mar

Hyd

mor

Pot p

ec

Alg

fil

resi

dual

RPM

(%

Fig. 7

1 2 3 4 5MMT, MMO

But umb

Cer dem

Elo nut

Hyd mor

Lem min

Lem tri

Myr spi

Naj mar

Nup lut

Nym alb

Pol amp

Pot cri

Pot luc

Pot nod

Pot pec

Pot per

Ran cir

Ran tri

Ror amp

Sal nat

Spi pol

Ric flu

Tra nat

Alg fil

0 0,5 1d

Fig. 8

strech 59 61 63 64 65 67 70 72 74 75 76 77 79 80 81 83 84 85 90 92

Pot luc

Myo pal

Myr ver

Pot cri

Men aqu

Pot pec

Cal cop

Cha foe

Cha fra

Elo can

Elo nut

Ele aci

Hip vul

Myr spi

Pot per

Pot pus

Ran cir

Gro den

Ran tri

Spa eme

Utr vul

Cha his

Zan pal

Alg fil

Api rep

Fig. 9

Fig. 9

0

10

20

30

40

50

60

70

80

90

100

Cha

foe

Cha

his

Pot p

us

Elo

can

Ran

cir

Myr

spi

Pot p

er

Spa

eme

Elo

nut

Myo

pal

Gro

den

Alg

fil

Cha

fra

Myr

ver

Zan

pal

Pot p

ec

Pot l

uc

resi

dual

RPM

( %

Fig. 10

1 2 3 4 5MMT, MMO

Alg fil

Ran tri

Spa eme

Utr vul

Zan pal

Pot pec

Pot per

Pot pus

Ran cir

Myr spi

Myr ver

Pot cri

Pot luc

Gro den

Hip vul

Men aqu

Myo pal

Cha his

Elo can

Elo nut

Ele aci

Api rep

Cal cop

Cha foe

Cha fra

0 0,5 1d