Analele Științifice ale Universității „Al. I. Cuza” Iași, s. Biologie animală, Tom LVII, 2011

THE SYNECOLOGICAL ANALYSE OF THE FALCONIFORMES

SPECIES ACCORDING TO THEIR AERIAL ACTIVITY

Adrian MESTECĂNEANU1 and Florin MESTECĂNEANU2

1Argeș County Museum, Armand Călinescu, 44, 110047, Pitești, Argeș, Romania, mestecaneanua@yahoo.com

2Dârmănești, 117360, Argeș, Romania, mestecaneanuf@yahoo.com

Abstract. In this paper, the authors present a part of the results regarding the research of the Falconiformes

species observed on the wing between March 2005 and February 2008 on the Doamnei River hydrographic

basin. 20 species were registered in order to their synecological analyse using the constancy, the dominancy, the

Dzuba index of ecological significance, the Shannon-Wiener and Simpson diversities and the equitability.

Keywords: Falconiformes, ecological indexes, Buteo buteo.

Rezumat. In această lucrare, autorii prezintă o parte a rezultatelor privind studiul speciilor de falconiforme

observate în zbor în perioada martie 2005 – februarie 2008 în bazinul hidrografic Râul Doamnei. Au fost

înregistrate 20 de specii, în vederea analizei sinecologice a acestora luându-se în calcul constanța, dominanța,

indicele de semnificație ecologică Dzuba, diversitatea Shannon-Wiener și Simpson, precum și echitabilitatea.

Cuvinte cheie: falconiforme, indici ecologici, Buteo buteo.

Introduction

Extended researches about the Falconiformes species from the Doamnei River hydrographic basin have not been done until now. There is only a single paper (Mătieș,

1974) regarding this aspect, taking into account the situation of these birds between 1967

and 1973 in the Argeș County, including the area of this study. The author found 15

species: Falco tinnunculus (42.8% of all Falconiformes observed individuals) Buteo buteo

(42%), Accipiter nisus (4,7%), Falco subbuteo (1.6%), Aquila chrysaetos (1.3%), Aquila

pomarina (1.3%), Buteo lagopus (1.3%), Accipiter brevipes (0.9%), Circus cyaneus

(0.7%), Accipiter gentilis (0.5%), Falco vespertinus (0.4%), Hieraetus pennatus (0.4%),

Circus aeruginosus (0.2%), Falco peregrinus (0.2%) and Milvus migrans (with 0.2%).

Our research represents a part of a larger study about the birds that have a

pronounced aerial activity, which mainly includes researches regarding the influence on

flying of such factors as: hour, temperature, atmospheric nebulosity, type of clouds, force

of the wind etc.

Materials and Methods

The Doamnei River is 109.1 km long and its hydrographic basin has 1822 km2.

The difference of level of 2284 m between the Moldoveanu Peak (2544 m) from the

Făgăraș Massif and the point of confluence with the Argeș River (260 m) from the High

Plain of Pitești (Barco & Nedelcu, 1974) offers a great diversity of relief and habitats

favourable for the birds (Fig. 1).

In this work, our purpose was to give an image about the relations established in

every ecological season between the species of Falconiformes observed on flying during

March 2005 – February 2008 in the River Doamnei hydrographic basin and also about the

hierarchy that are established. In this purpose we did their sinecologic analyze. Also, we evaluated the ecological diversity and the equitability.

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Adrian Mestecăneanu & Florin Mestecăneanu

Results and Discussion

20 species of Falconiformes were identified: Aquila chrysaetos (0.07% of all

Falconiformes observed individuals), Aquila clanga (0.08%), Aquila pomarina (1.41%),

Circaetus gallicus (0.20%), Buteo buteo (56.40%), Buteo lagopus (0.01%), Pernis

apivorus (8.87%), Accipiter gentilis (5.77), Accipiter nisus (14.32%), Milvus migrans (0.05%), Pandion haliaetus (0.02%), Circus aeruginosus (3.34%), Circus pygargus

(0.57%), Circus cyaneus (0.35%), Circus macrourus (0.02%), Falco subbuteo (4.43%),

Falco columbarius (0.08%), Falco vespertinus (1.78%), Falco naumanni (0.05%) and

Falco tinnunculus (2.17%). Their seasonal distribution: 7 species (35% from the whole

number of the species observed) in the hiemal aspect (Buteo buteo, Buteo lagopus,

Accipiter gentilis, Accipiter nisus, Circus cyaneus, Falco columbarius and Falco

tinnunculus), 17 species (85%) in the prevernal aspect (Aquila clanga, Aquila pomarina,

Circaetus gallicus, Buteo buteo, Buteo lagopus, Pernis apivorus, Accipiter gentilis,

Accipiter nisus, Milvus migrans, Circus aeruginosus, Circus pygargus, Circus cyaneus,

Circus macrourus, Falco subbuteo, Falco columbarius, Falco vespertinus and Falco

Figure 1. The hydrographic basin of the Doamnei River (modified by

Barco & Nedelcu, 1974). - the zone limit.

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Analele Științifice ale Universității „Al. I. Cuza” Iași, s. Biologie animală, Tom LVII, 2011

tinnunculus), 12 species (60%) in the vernal aspect (Aquila pomarina, Circaetus gallicus,

Buteo buteo, Pernis apivorus, Accipiter gentilis, Accipiter nisus, Pandion haliaetus, Circus aeruginosus, Circus pygargus, Falco subbuteo, Falco vespertinus and Falco

tinnunculus), 9 species (45%) in the aestival aspect (Aquila chrysaetos, Aquila pomarina,

Circaetus gallicus, Buteo buteo, Pernis apivorus, Accipiter gentilis, Accipiter nisus, Falco

subbuteo and Falco tinnunculus), 13 species (65%) in the serotinal aspect (Aquila

chrysaetos, Aquila pomarina, Circaetus gallicus, Buteo buteo, Pernis apivorus, Accipiter

gentilis, Accipiter nisus, Pandion haliaetus, Circus aeruginosus, Circus pygargus, Falco

subbuteo, Falco vespertinus and Falco tinnunculus) and 16 species (80%) in the autumnal

aspect (Aquila chrysaetos, Aquila pomarina, Circaetus gallicus, Buteo buteo, Pernis

apivorus, Accipiter gentilis, Accipiter nisus, Milvus migrans, Circus aeruginosus, Circus

pygargus, Circus cyaneus, Falco subbuteo, Falco columbarius, Falco vespertinus, Falco

naumanni and Falco tinnunculus).

The ecological indicators used (conformable to the way of calculation) belong to two categories: analytical ecological indexes – frequency (constancy), richness and

dominance – and synthetic ecological indexes – Dzuba index of ecological signification –

(Gomoiu & Skolca, 2001).

According to the constancy, we noted that accidental species had the most

weight each season. Their maximum was reached during migration, in the prevernal and

autumnal aspects and the minimum in the hiemal and aestival aspects. The most numerous

accessory species was recorded in the vernal aspect and the least numerous in the

autumnal one. The constant species had a minimum level from the autumnal season to the

vernal one. It gradually augmented up to the serotinal season, when were registered the

most of them. The euconstant species remained the same (one species from the hiemal

season to the serotinal season), while in the autumnal season was attained the maximum of two species (Table 1, Fig. 2).

We observe that Buteo buteo was permanently euconstant species. Pernis

apivorus was constant from the vernal season to the serotinal one, only in the prevernal

and vernal aspects (at the beginning of the spring migration and at the ending of the

autumn migration) being accidental species. Accipiter gentilis was mainly accessory

species, in the aestival aspect becoming accidental species and in the autumnal one,

constant species. Falco subbuteo was accidental species in the prevernal and autumnal

aspects, accessory in the vernal and aestival aspects, and constant in the serotinal one. The

0

2

4

6

8

10

12

14

16

Hie

mal

aspect

Pre

vern

al

aspect

Vern

al

aspect

Estival

aspect

Sero

tinal

aspect

Autu

mnal

aspect Aspect

Number of

species

Euconstant

Constant

Accesory

Accidental

Figure 2. The diagram of variation of the constancy categories by the ecological seasons.

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Adrian Mestecăneanu & Florin Mestecăneanu

other species (Aquila chrysaetos, Aquila clanga, Aquila pomarina, Circaetus gallicus,

Buteo lagopus, Milvus migrans, Pandion haliaetus, Circus aeruginosus, Circus pygargus, Circus cyaneus, Circus macrourus, Falco columbarius, Falco vespertinus, Falco

naumanni and Falco tinnunculus), when they were present, were accidental species (Table

1).

Table 1. The ecological indexes of the observed Falconiformes species (in the EURING Code) in

the Doamnei River hydrographic basin, according to the ecological seasons.

Ecological

indexes

Species

Ab

solu

te f

req

uen

cy

(n

o. o

f

da

ys

wit

h o

bse

rv

ati

on

s)

Co

nst

an

cy

Ca

teg

ory

of

co

nst

an

cy

Ric

hn

ess

Do

min

an

ce

Ca

teg

ory

of

do

min

an

ce

Ind

ex

o

f e

co

log

ica

l

sig

nif

ica

tio

n D

zu

ba

Ca

teg

ory

of

th

e i

nd

ex

o

f

eco

log

ica

l si

gn

ific

ati

on

Dzu

ba

Sh

an

on

-Wie

ner i

nd

ex

H(S

)ma

x

Eq

uit

ab

ilit

y

Sim

pso

n I

nd

ex

(1

/λ)

S

Eq

uit

ab

ilit

y

Hiemal aspect

Butbut 211 80.228 C4 819 69.643 D5 55.873 W5

0.89 1.95 0.46 1.88 7 0.27

Butlag 1 0.380 C1 1 0.085 D1 0.001 W1

Accgen 68 25.856 C2 94 7.993 D4 2.067 W3

Accnis 147 55.894 C3 236 20.068 D5 11.217 W5

Circya 8 3.042 C1 13 1.105 D2 0.034 W1

Falcol 4 1.521 C1 4 0.340 D1 0.005 W1

Faltin 7 2.662 C1 9 0.765 D1 0.020 W1

Prevernal aspect

Aqucla 3 2.273 C1 7 0.395 D1 0.009 W1

1.14 2.83 0.40 1.90 17 0.11

Aqupom 9 6.818 C1 16 0.902 D1 0.062 W1

Cirgal 2 1.515 C1 2 0.113 D1 0.002 W1

Butbut 125 94.697 C4 1264 71.292 D5 67.511 W5

Perapi 4 3.030 C1 7 0.395 D1 0.012 W1

Accgen 55 41.667 C2 97 5.471 D4 2.280 W3

Accnis 89 67.424 C3 201 11.337 D5 7.644 W4

Milmig 2 1.515 C1 3 0.169 D1 0.003 W1

Ciraer 20 15.152 C1 52 2.933 D3 0.444 W2

Cirpyg 12 9.091 C1 16 0.902 D1 0.082 W1

Circya 2 1.515 C1 2 0.113 D1 0.002 W1

Cirmac 1 0.758 C1 2 0.113 D1 0.001 W1

Falsub 8 6.061 C1 11 0.620 D1 0.038 W1

Falcol 1 0.758 C1 1 0.056 D1 0.001 W1

Falves 16 12.121 C1 51 2.876 D3 0.349 W2

Falnau 3 2.273 C1 3 0.169 D1 0.004 W1

Faltin 27 20.455 C1 38 2.143 D3 0.438 W2

Vernal aspect

Aqupom 15 13.043 C1 23 1.904 D2 0.248 W2

1.52 2.48 0.61 2.76 12 0.23

Cirgal 5 4.348 C1 5 0.414 D1 0.018 W1

Butbut 112 97.391 C4 694 57.450 D5 55.952 W5

Perapi 66 57.391 C3 169 13.990 D5 8.029 W4

Accgen 31 26.957 C2 42 3.477 D3 0.937 W2

Accnis 37 32.174 C2 66 5.464 D4 1.758 W3

Panhal 1 0.870 C1 1 0.083 D1 0.001 W1

Ciraer 17 14.783 C1 22 1.821 D2 0.269 W2

Cirpyg 9 7.826 C1 14 1.159 D2 0.091 W1

Falsub 41 35.652 C2 79 6.540 D4 2.332 W3

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Analele Științifice ale Universității „Al. I. Cuza” Iași, s. Biologie animală, Tom LVII, 2011

Ecological

indexes

Species

Ab

solu

te f

req

uen

cy

(n

o. o

f

da

ys

wit

h o

bse

rv

ati

on

s)

Co

nst

an

cy

Ca

teg

ory

of

co

nst

an

cy

Ric

hn

ess

Do

min

an

ce

Ca

teg

ory

of

do

min

an

ce

Ind

ex

o

f e

co

log

ica

l

sig

nif

ica

tio

n D

zu

ba

Ca

teg

ory

of

th

e i

nd

ex

o

f

eco

log

ica

l si

gn

ific

ati

on

Dzu

ba

Sh

an

on

-Wie

ner i

nd

ex

H(S

)ma

x

Eq

uit

ab

ilit

y

Sim

pso

n I

nd

ex

(1

/λ)

S

Eq

uit

ab

ilit

y

Falves 21 18.261 C1 62 5.132 D4 0.937 W2

Faltin 17 14.783 C1 31 2.566 D3 0.379 W2

Aestival aspect

Aquchr 1 0.746 C1 2 0.170 D1 0.001 W1

1.52 2.20 0.69 3.54 9 0.39

Aqupom 16 11.940 C1 19 1.618 D2 0.193 W2

Cirgal 2 1.493 C1 5 0.426 D1 0.006 W1

Butbut 116 86.567 C4 512 43.612 D5 37.753 W5

Perapi 96 71.642 C3 306 26.065 D5 18.673 W5

Accgen 28 20.896 C1 33 2.811 D3 0.587 W2

Accnis 79 58.955 C3 145 12.351 D5 7.282 W4

Falsub 60 44.776 C2 95 8.092 D4 3.623 W3

Faltin 29 21.642 C1 57 4.855 D3 1.051 W3

Serotinal aspect

Aquchr 1 0.763 C1 3 0.198 D1 0.002 W1

1.78 2.56 0.69 4.45 13 0.34

Aqupom 23 17.557 C1 38 2.507 D3 0.440 W2

Cirgal 2 1.527 C1 2 0.132 D1 0.002 W1

Butbut 113 86.260 C4 592 39.050 D5 33.684 W5

Perapi 85 64.885 C3 270 17.810 D5 11.556 W5

Accgen 53 40.458 C2 104 6.860 D4 2.775 W3

Accnis 98 74.809 C3 231 15.237 D5 11.399 W5

Panhal 1 0.763 C1 1 0.066 D1 0.001 W1

Ciraer 28 21.374 C1 107 7.058 D4 1.509 W3

Cirpyg 12 9.160 C1 13 0.858 D1 0.079 W1

Falsub 69 52.672 C3 129 8.509 D4 4.482 W3

Falves 2 1.527 C1 2 0.132 D1 0.002 W1

Faltin 12 9.160 C1 24 1.583 D2 0.145 W2

Autumnal aspect

Aquchr 1 0.763 C1 1 0.058 D1 0.001 W1

1.47 2.77 0.53 2.80 16 0.17

Aqupom 9 6.870 C1 25 1.447 D2 0.099 W1

Cirgal 3 2.290 C1 3 0.174 D1 0.004 W1

Butbut 122 93.130 C4 955 55.266 D5 51.469 W5

Perapi 5 3.817 C1 9 0.521 D1 0.020 W1

Accgen 69 52.672 C3 125 7.234 D4 3.810 W3

Accnis 108 82.443 C4 349 20.197 D5 16.651 W5

Milmig 1 0.763 C1 1 0.058 D1 0.001 W1

Ciraer 22 16.794 C1 105 6.076 D4 1.020 W3

Cirpyg 5 3.817 C1 6 0.347 D1 0.013 W1

Circya 8 6.107 C1 15 0.868 D1 0.053 W1

Falsub 26 19.847 C1 66 3.819 D3 0.758 W2

Falcol 2 1.527 C1 2 0.116 D1 0.002 W1

Falves 16 12.214 C1 38 2.199 D3 0.269 W2

Falnau 1 0.763 C1 1 0.058 D1 0.001 W1

Faltin 20 15.267 C1 27 1.563 D2 0.239 W2

Legend: C1, C2, C3, C4 – categories of constancy, D1, D2, D3, D4, D5 – categories of dominancy,

W1, W2, W3, W4, W5 – categories of index of ecological signification.

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Adrian Mestecăneanu & Florin Mestecăneanu

Regarding the dominancy, we remarked that the subrecedent species constituted

almost twice the number of other species (in the prevernal season) and the same number (in the autumnal season), aspects when the main maximum and secondary maximum

respectively of their curve of variation were reached. The minimum was recorded in the

vernal and aestival aspects. The most recedent species was recorded in the vernal season

and the least in the prevernal season (0 species). Instead, in the prevernal season were

observed the most subdominant species and the least in the hiemal season (0 species). The

maximum of the dominant species was in the vernal and serotinal aspects, the minimum

being in the hiemal, prevernal and aestival aspects. Regarding to the eudominant species,

the most numerous were registered in the aestival and serotinal seasons (3 species), in the

rest of time, 2 species being present (Table 1, Fig. 3).

Buteo buteo was always an eudominant species. Accipiter gentilis was a

dominant species except in the vernal and aestival seasons when it was subdominant

species. Accipiter nisus was generally eudominant species, only in the vernal season being

dominant. Falco tinnunculus was subrecedent in the hiemal season, subdominant in the

prevernal, vernal and aestival aspects, and recedent, in the serotinal and autumnal aspects.

Among the species that were not found all the year in the area, Aquila pomarina was

subrecedent in the prevernal season, recedent, in the vernal, aestival and autumnal ones, and subrecedent, in the serotinal one. Pernis apivorus was subrecedent species in the

prevenal and autumnal aspects, in the rest of time ascending with Buteo buteo in the

eudominant species category. Circus aeruinosus was subdominant species in the prevernal

season and recedent species in vernal one, while in the serotinal and autumnal seasons

was dominant species. Circus pygargus and Circus cyaneus, when present, were generally

subrecedent species, the first being recedent in the vernal season and the second in hiemal

one. After being a subrecedent species, Falco subbuteo remained from the vernal season

to the serotinal one in the category of the dominant species; in the autumnal season it was

subdominant species. Falco vespertinus, species present only in the passage, was

dominant in the vernal season, subdominant in the prevernal and autumnal aspects and

subrecedent, in the serotinal aspect. Other species (Aquila chrysaetos, Aquila clanga,

Circaetus gallicus, Buteo lagopus, Milvus migrans, Pandion haliaetus, Circus macrourus, Falco columbarius and Falco naumanni), when present, was constantly subrecedent.

About the Dzuba index of ecological signification, we observed that, except the

vernal and aestival seasons, the subrecedent species were the most numerous. Their

maximum was in the prevernal and autumnal aspects and their minimum in the aestival

Figure 3. The diagram of variation of the dominancy categories by the ecological seasons.

0

2

4

6

8

10

12

Hie

mal

aspect

Pre

vern

al

aspect

Vern

al

aspect

Estival

aspect

Sero

tinal

aspect

Autu

mnal

aspect Aspect

Number of

speciesEudominant

Dominant

Subdominant

Recedent

Subrecedent

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Analele Științifice ale Universității „Al. I. Cuza” Iași, s. Biologie animală, Tom LVII, 2011

season. In the hiemal season was not observed any species, in the aestival and serotinal

seasons were observed two species of each of them, in the prevernal and autumnal seasons three species of each of them and in the venal season were observed the most (5 species).

An interesting evolution had the subdominant species, which had a progressive increase

from the hiemal season (1 species) to the serotinal one (3 species). A remarkable

evolution had also the dominant species, during the prevernal season to the aestival season

being one species and in rest of time, 0 species. In the prevernal and vernal seasons, was

only one eudominant species, in the hiemal, aestival and autumnal seasons were two

species and in the serotinal season, three species (Table 1, Fig. 4)

Buteo buteo was the only species eudominant in each ecological aspect. Accipiter

gentilis was subdominant species except the vernal and aestival aspects, when it was

recedent species. Accipiter nisus was mainly an eudominant species, in the prevernal and

aestival aspects being dominant species and, in the vernal aspect, subdominant. Falco

tinnunculus was, usually, recedent species, only in the hiemal aspect being subrecdent and

in the aestival one, subdominant species. Among the migratory species, Aquila pomarina

was subrecedent species in the prevernal aspect, recent species in the vernal, aestival and

atumnal aspects and subrecedent species in the serotinal one. Pernis apivorus was

subrecedent species in the prevernal and autumnal aspects, dominant in the vernal aspect

and eudominant species in the aestival and serotinal ones. Circus aeruginosus was

recedent species in the prevernal and vernal aspects and subdominant species in serotinal and autumnal aspects. Falco subbuteo was subrecedent in the prevernal aspect, recedent in

the autumnal aspect, and subdominant species from the vernal aspect to the serotinal one.

Excepting the serotinal aspect, when it was subrecedent species, Falco vespertinus was

recedent species. The other species (Aquila chrysaetos, Aquila clanga, Circaetus gallicus,

Buteo lagopus, Milvus migrans, Pandion haliaetus, Circus pygargus, Circus cyaneus,

Circus macrourus, Falco columbarius and Falco naumanni), when present, were

subrecedent species.

From the diversity point of view (Table 1, Fig. 5), the Shannon-Wiener index

varied generally ascendantly from the hiemal season to the serotinal one. The index

follows a sharp down from the serotinal season to the hiemal one. Alike is in the situation

of the Simpson index, with the mention that the increasing (more pregnant and more linear) begins from the minimum level situated in the hiemal and prevernal aspects. For

Figure 4. The diagram of variation of the Dzuba index categories by the ecological seasons.

0

2

4

6

8

10

12

Hie

mal

aspect

Pre

vern

al

aspect

Vern

al

aspect

Estival

aspect

Sero

tinal

aspect

Autu

mnal

aspect Aspect

Number of

speciesEudominant

Dominant

Subdominant

Recedent

Subrecedent

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Adrian Mestecăneanu & Florin Mestecăneanu

every index, the minimums correspond to the minimum stability and the maximums to the

maximum stability of the Falconiformes community, the differences coming because the Shannon-Wiener index gives a bigger value for the rare species while the Simpson index

gives a bigger value for the dominant species.

Regarding the equitability (Table 1, Fig. 5), it is an obvious similarity between

the variation curves of the both calculated equitability. The minimums are placed each

time in the prevernal aspect and the maximums in the aestival and serotinal, for the

Shannon-Wiener equitability, and in the aestival aspect, for the Simpson equitability. So,

the real diversity is the closest to the maximal one in the aestival season, when the

Falconiformes population is more equilibrated from the point of view of the species

number of individuals and it is the farthest in the prevernal aspect, when the population is

in an obvious disequilibrium because of great difference between the numbers of

individuals of Buteo buteo and Accipiter nisus, on the one hand, and the other species on

the other hand.

Conclusions

Between March 2005 and February 2008, by the method of flying birds’

observations, in the Doamnei River hydrographic basin, we found 20 species of

Falconiformes (Aquila chrysaetos, Aquila clanga, Aquila pomarina, Circaetus gallicus,

Buteo buteo, Buteo lagopus, Pernis apivorus, Accipiter gentilis, Accipiter nisus, Milvus

migrans, Pandion haliaetus, Circus aeruginosus, Circus pygargus, Circus cyaneus,

Circus macrourus, Falco subbuteo, Falco columbarius, Falco vespertinus, Falco

naumanni and Falco tinnunculus), with 5 species more than Mătieș who recorded 15

species of birds (settled or on the wing) during 1967 – 1973, in the whole Argeș County.

Eight new species was registered: Aquila clanga, Circaetus gallicus, Pernis apivorus, Pandion haliaetus, Circus pygargus, Circus macrourus, Falco columbarius and Falco

naumanni, Pernis apivorus taking the most significance weight of them (8.87%). Three

species were not found: Accipiter brevipes, Hieraetus pennatus and Falco peregrinus. The

difference of percentage between the species observed in both studies reflects the

dynamics of Falconiformes community, on the one hand, and the differentiation between

the researched zones from the point of view of the habitats proportion, on the other hand.

Also, it was influenced more or less by the two different used methods of study.

Figure 5. The seasonal variation of the Shanon-Wiener and Simpson indexes and of the equitability.

00.5

11.5

22.5

33.5

44.5

5

Hie

mal

aspect

Pre

vern

al

aspect

Vern

al

aspect

Estival

aspect

Sero

tinal

aspect

Autu

mnal

aspect

Aspect

Index value

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Equitability

value

Shanon-Wiever

Index

Simpson Index

(1/λ)

Shanon-Wiever

equitability

Simpson

equitability

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Analele Științifice ale Universității „Al. I. Cuza” Iași, s. Biologie animală, Tom LVII, 2011

According to the constancy, we noted that accidental species were preponderant

each season. Instead, the euconstant species remained one species from the hiemal season to the serotinal season, in the autumnal season being attained the maximum of two

species. Buteo buteo was permanently euconstant species.

Regarding the dominancy, we remarked that the subrecedent species constituted

almost twice the number of other species (in the prevernal season) and the same number

(in the autumnal season). Relative to the eudominant species, the most numerous were

registered in the aestival and serotinal seasons (3 species), in the rest of time, 2 species

being present. Buteo buteo was always eudominant species.

About the Dzuba index of ecological signification, we observed that, except the

vernal and aestival seasons, the subrecedent species were, each time, the most numerous.

Instead was only one eudominant species in the prevernal and vernal seasons, two species

in the hiemal, aestival and autumnal seasons and three species in the serotinal season.

Buteo buteo was again only eudominant species, each ecological aspect. The Shannon-Wiener and Simpson diversities varied alike, with the minimums in

the hiemal and prevernal seasons (when the stability was the most reduced), and with the

maximums in the serotinal aspect (when the stability was the highest).

Regarding the equitability, the real diversity is the closest to the maximal one in

the estival season, and the furthest in the prevernal aspect.

References

Barco, A., Nedelcu, E., 1974. Județul Argeș. Editura Academiei Republicii Socialiste România, București.

Gomoiu, M.T., Skolka, M., 2001. Ecologie. Metodologii pentru studii ecologice. Ovidius University Press,

Constanța.

Mătieș, M., 1974. Contribuții privind cunoașterea situației actuale a păsărilor răpitoare de zi, ord. Falconiformes,

din județul Argeș (perioada 1967 - 1973). Nymphaea, Muzeul Țării Crișurilor, Oradea, II: 129-136.

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