studia universitatis babeş-bolyai biologia 2

V. POPA
The highest relative abundance (RA%) has been recorded for Diplocolenus
bohemani (55.69% in spruce forests, 37.78% in meadows and 25% in pastures),
followed by Verdanus abdominalis (98.86% in spruce forests, 28.26% in meadows,
60% in pastures and 10% in swampland). The different levels of the RA% show
that the two species have different ecological needs: Verdanus abdominalis is a
species that lives in open areas, and Diplocolenus bohemani prefers the forests.
Low values of the RA% were found for Erythria montandoni, Dikraneura sp. and
Philaenus spumarius (0.63%).
The highest values of the dominance index (D%) were registered for
Diplocolenus bohemani (38.80%) and Verdanus abdominalis (32.46%). All ecosystems
in the studied area were numerically dominated by these two species.
The values of the Shannon-Weawer ecological diversity and of the equitability
indices are presented in Table 2. By analysing this table, one can see that we have
found the highest value of the diversity index in the meadow (0.73), followed by
the spruce forest (0.64), and the lowest value was registered for the swampland
ecosystem (0.18). Regarding the values of the equitability indices, the situation is
similar. This result shows that the cicada species mainly prefer open ecosystems,
such as meadows and subalpine pastures and also the spruce forests. The fact that
the cicada species prefer these two types of ecosystems may be due to the richness
of the trophic base, and also to the temperature and humidity conditions that favour
the development of these types of communities. In the spruce forest the trophic
base is also rich, due to the substantial herbaceous layer.
Table 2
Values of the Shannon-Weaver diversity index (H') and
equitability index (e) in the studied ecosystems
Index
Type of ecosystem
Spruce forest Pine forest Meadow Pasture Swampland
H' 0.64 0.3 0.73 0.48 0.18
e 0.61 0.6 0.67 0.2 0.12
Conclusions. 1.In the studied area, we have identified 21 species belonging
to 19 genera, 2 families and 4 subfamilies. The cicada fauna is relatively reduced.
2. The majority of the species belong to the family Cicadellidae Latreille, 1825.
3. The most abundant cicada fauna lives in meadows and subalpine pastures.
Also, a great number of species live in spruce forests. The cicada fauna is less represented
in swamplands and pine forest.
4. The studied area presents a high percentage of stenobiont species (48%).
5. The species with the highest relative abundance are Diplocolenus bohemani and
Verdanus abdominalis, and those with the lowest abundance are Erythria montandoni,
Dikraneura sp. and Philaenus spumarius.
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