biologia - Studia

STRUCTURE AND DYNAMICS OF THE PREDATOR MITE’S POPULATIONS IN SHRUBS ECOSYSTEMS
of the numerical densities was different in the other ecosystems. At Cornu, in
autumn, the predator mites had a favourable evolution, in comparison with spring,
when was recorded a decreasing of the population. In ecosystems from Nistoreşti,
in spring and autumn months, due to the favourable bioedaphical conditions (more
increased humidity), the gamasid populations increased their number of
individuals. In august they decreased considerable (Fig. 1.).
5000
4500
Lunca Mare
Cornu
Nistoresti
4000
3500
no.ind./sq.m.
3000
2500
2000
1500
1000
500
0
May August October
Fig. 1. Numerical densities of the mite’s populations from the studied ecosystems.
Taking account of the soil levels, on the litter and fermentation layer,
where were recorded the highest values of the humidity (between 27,38%-
35,95%), the predator mite’s populations had the most increased numerical
densities, in all studied areas. The litter and fermentation layer through broken up
structure, provided development of the gamasids in better conditions, in comparison
with humus and soil layer. In the soil level (S 2 ) were identified the most decreased
number of individuals, with exception of the ecosystem from Lunca Mare. (Fig. 2.).
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