Obavljen je faunistički, biocenozni i ekološki pregled zajednica makrozoobentosa mekih dnajužnog dijela tršćanskog zaljeva na temelju uzorkovanja u 2005. i 2006. godini. Uzorci su prikupljanina 28 ...postaja, a ukupno je sakupljeno 14 595 primjeraka organizama odnosno određeno je306 životinjskih svojti. Najbrojnije vrste su Capitella capitata, Lumbrineris gracilis, Heteromastusfiliformis, Corbula gibba i Tellina distorta. Najveća relativna brojnost vrsta u svim vodenim tijelimaiznosila je blizu 15%. Dominantna vrsta je potvrdila da je okruženje u tršćanskom zaljevu nestabilno.Ova nestabilnost okoliša također može objasniti prilično visoke AMBI vrijednosti. MDS analizei druge primjene indeksa ukazuju da nema statistički značajne razlike između vodenih tijela. Vrijednostiza Shannon-Wiener indeks raznolikosti (H‘) i Pielou indeks (J’) bile su prema sastavu međunajvišim ikada zabilježenim za mekana dna u tršćanskom zaljevu. Analiza bentoske biocenoze jeotkrila da je područje uzimanja uzoraka granica između infra-i cirkalitoralnog pojasa, što bi mogloobjasniti izuzetno bogatstvo vrsta.
A faunistic, biocoenotic and ecological survey of soft-bottom macrozoobenthic communities was carried out for the southern part of the Gulf of Trieste on the basis of samplings in 2005 and 2006. At 28 sampled stations a total of 14595 specimens belonging to 306 animal taxa were identified. The most abundant species were Capitella capitata, Lumbrineris gracilis, heteromastus filiformis, Corbula gibba and Tellina distorta. The highest relative species abundance in all water bodies was close to 15%. The dominant species confirmed that the environment of the Gulf of Trieste is unstable. This environmental instability could also explain the rather high values of AMBI. The MDS analysis and other applied indices indicated that there were no statistically significant differences between water bodies. The values for Shannon-Wiener diversity index (H’) and Pielou’s index (J’) were among the highest ever recorded for the soft-bottom assemblages of the Gulf of Trieste. The analysis of benthic biocoenoses revealed that the sampling area is a boundary between infra- and circalittoral belts, which could explain the very high species richness.
In the course of 1963. the studies on the soil »respiration« were done in some forest communities on the low mountain Fruska Gora in Srem in the vicinity of Novi Sad (Vojvodina, Serbia, Pannonian ...Plain). The studies were done comparatively in the following three forest communities, their stands being situated at the altitude of about 500 m.: 1. Querco -Carpinetum serbicum Rudski, 2. Festuco-Quercetum petreae M. Jank. and 3. Acetosello-Quercetum petreae M. Jank and V. Mis. The first mentioned community represented a mixed chestnut oak (Quercus petrea) and hornbeam (Carpinus betulus) forest, rather meso- phytic in character, situated on a northwards sloped vast plateau. Beside the mentioned tree species and a number of bushes, particularly significant were also Melica uniflora, Rubus hirtus, Hedera helix, Stellaria holostea, Galanthus nivalis, Galium silvaticum, etc. In the community Festuco-Quercetum petreae, represented in our studies by a degraded variant situated on a very steep southward slope, beyond the edifying oak species (Quercus petrea), Festuca montana was particularly significant as edifying species in the herb stratum. The edifying species in the community Acetosello-Quercetum petreae, situated on a narrow and steep crest of a southwards facing ridge, was represented by Quercus petrea (with short supressed trunks), while in the scattered and poorly developed herb stratum the most significant species were Rumex acetosella, Sedum maximum, Thlaspi perfoliatum, Draba vema, Hierecium bauchini, Cytisus nigricans etc.
The Schwertfeger’s CO2 fixation method was applied (according to Walter, 1951.) the quantity of the produced CO2, being calculated per square meter of the soil surface (g/m2). The estimates of the produced CO2, were done twice a month, from May to October 1963., and the dayly estimates every 4 hours from 6 a. m. to 6 p. m.; nightly values of the fixed C02 concern the interval between 6 p. m. of the previous day and 6 a. m. of the following one. In order to establish the importance of the litter for the soil »respiration« effect, the C02 production was studied comparatively in two sampling areas: the one preserved in its natural condition the other being devoid of its litter and herb stratum.
The obtained results could be summarized as follows.
As regards the seasonal dynamics of the CO2, production, according to the used parameters, a markedly high CO2 production takes place in June and July in every of the three studied communities; an expressed decline occurs in August (in Querco-Carpinetum serbicum it occurs also in July), followed by a new increase in September and again by a new depression in October.
The comparison of the dayly and nightly values of the C02 production shows crearly that they are higher by night. Dayly course of the C02 production dynamics is subject to considerable variations and this refers to both the monthly observations and the observations on two consecutive days. Generally, one observes in all months a decline of the CO2 production intensity in morning hours and its corresponding increase in the afternoon hours. The maximum dayly values of the produced carbon dioxide in the communities Querco-Carpinetum serbicum and Festuco -Quercetum petreae were recorded in June, and in the community Acetosello-Quercetum petreae in September.
The quantities of the C02 produced by night show extensive variations both according to months and inside each of the studied communiteis. Nevertheless, as already mentioned, the C02 production intensity was always higher by night.
In respect to the litter effect it could be established that the CO2 production on the undisturbed sufrace, with the litter and herb stratum preserved, was mainly markedly higher than on the denuded surfaces, and this applies to all the three studied communities throughout the year. Although the litter and herb stratum effect on the soil »respiration« must be very complex, it could be probably ascribed in the first place to the effects of the organic decomposition inside litter itself, namely at the contact between litter and humus.
Through the comparison of the three studied forest communities it becomes evident that the community Acetosello-Quercetum petreae is charasterized by the highest soil production of C02; this could be explained as a result of the higher rate of organic decomposition in its floor, due to the higher soil temperature which is characteristic of that southward exposed community. The CO2, production in the community Festuco -Quercetum petreae was slightly lower, and the lowest production was in the community Qaerco—Carpinetum serbicum. Characteristic of the latter community is a high soil production of CO2, in June and a relatively low production during the following months until October. This would be the essential difference between the community Querco—Carpinetum serbicum on the mountain Fruska Gora and the two remaining studied communities. It could be ascribed in the first place to their different hygric and thermic regimes which are a consequence of their fundamental habitat and cenotical particularities.
Obavljen je faunistički, biocenozni i ekološki pregled zajednica makrozoobentosa mekih dna
južnog dijela tršćanskog zaljeva na temelju uzorkovanja u 2005. i 2006. godini. Uzorci su prikupljani
na 28 ...postaja, a ukupno je sakupljeno 14 595 primjeraka organizama odnosno određeno je
306 životinjskih svojti. Najbrojnije vrste su Capitella capitata, Lumbrineris gracilis, Heteromastus
filiformis, Corbula gibba i Tellina distorta. Najveća relativna brojnost vrsta u svim vodenim tijelima
iznosila je blizu 15%. Dominantna vrsta je potvrdila da je okruženje u tršćanskom zaljevu nestabilno.
Ova nestabilnost okoliša također može objasniti prilično visoke AMBI vrijednosti. MDS analize
i druge primjene indeksa ukazuju da nema statistički značajne razlike između vodenih tijela. Vrijednosti
za Shannon-Wiener indeks raznolikosti (H‘) i Pielou indeks (J’) bile su prema sastavu među
najvišim ikada zabilježenim za mekana dna u tršćanskom zaljevu. Analiza bentoske biocenoze je
otkrila da je područje uzimanja uzoraka granica između infra-i cirkalitoralnog pojasa, što bi moglo
objasniti izuzetno bogatstvo vrsta.
