The vegetation of prickly Juniper (Juniperus oxycedrus L. ssp. oxycedrus) shrublands of Mount Orvilos (E. Macedonia, Nomos Dramas, Greece)
Shrublands occupy the eastern part of Mount Orvilos, where the species Juniperus oxycedrus ssp. oxycedrus is the dominant species. Pinus nigra and Ostrya carpinifolia invade gradually in these formations, mainly in higher altitudes, and they successionally form pure forests. Eight (8) sample plots (relevés) were chosen in Orvilos, where vegetation of prickly Juniper shrublands has been studied using the Braun-Blanquet method. Juniperus oxycedrus ssp. oxycedrus – community has been identified and its structure and floristic composition has been researched, while at the same time, ecological, life – form and chorological spectra were presented.
Macromycetes in the Greek grasslands
As part of a long lasting project on recording and studying the Greek mycoflora, 52 species of Macrofungi were recorded in grasslands of Greece. Forty-five species were recorded solely in grasslands while 7 species were found also in other types of forest ecosystems. The distributions of these species in the different elevation zones were: Low-elevation – 41, Middle -16, High-elevation – 16 and Subalpine-10 species. Similarly, the distribution of the 255 records was low-elevation-159, Middle-44, High-elevation-31 and Subalpine-21. Certain species such as Calvatia utriformis and Agaricus sylvaticus were found only in the High-elevation and Subalpine zones while others such as Marasmius oreades and Stropharia coronilla were recorded mainly in the Low- and Middleelevation zones. The majority, however, were found in a wider altitude range. As a conclusion more species occur and more frequent fruiting appears in the Low- and Middle-elevation zones. 71,1% of the recorded species produced their carpophores in the autumn and only 12,2% in the summer. Similarly, 74,5% of the recordings was accomplished in the autumn and only 5,9% were recorded in the summer months. Out of the 52 recorded species only one is considered poisonous while 31 others are not edible. Among the 20 edible species a few are highly esteemed. The importance of mushrooms in the diet of the wild as well as the domestic animals is briefly discussed.
Productivity of five no irrigated leys and natural vegetation at Lithochori of Evritania
The productivity of five leys with five binary mixtures and indigenous vegetation was studied in mountainous area of Central Greece (altitude 1100 m). The binary mixtures were consisted by Lolium perenne and one of the following legumes: Lotus corniculatus, Medicago sativa, Trifolium hybridum, T. pratense and T. repens. Indigenous vegetation was used as control. Neither nitrogen fertilisation nor irrigation was applied. The productivity was 740-1600 and 560-1540 g m-2 dry matter for the first and the second year respectively. The most productive ley was that with T. repens. The botanical composition analysis showed that the contribution of L. perenne was relatively small. The productivity of indigenous vegetation was comparable with that of leys. Its botanical composition proved quite sufficient.
Effects of water buffalo (Bubalus bubalis) grazing on the vegetation of the littoral zone of Lake Mikri Prespa
Grazing by large domestic herbivores in littoral zones is a very effective means for management of littoral vegetation. As a result, wet meadows may be restored. Such meadows constitute ideal spawning grounds for fish, function as principal feeding grounds for many waterbirds and host large concentrations of invertebrates, amphibians and reptiles. In June 1997, five water buffaloes were introduced in a fenced area of 18 ha in Lake Mikri Prespa. Cover of plant functional types was measured in line transects that crossed the vegetation zones from the higher and dryer locations of the littoral zone to the lower and wetter ones. In addition, the height and density of the common reed (Phragmites australis) was recorded in freely grazed and protected plots. Measurements were initiated at the time of water buffalo introduction in 1997 and repeated in June 1998 and September 1999. The most important effect was the reduction of the common reed at the temporarily flooded zones and the increase of the amount of litter and bare ground on the grazed area.
Symbiotic N2-fixation by Trifolium repens using 15N natural abundance method (δ15Ν)
15N natural abundance method (δ15Ν) is used with success for over two decades for N2-fixation determination in natural, semi-natural and cultivated ecosystems. The application of this method is based on the differences that exist in 15N natural abundance (δ15Ν) in the plant tissues between a N2-fixing species (δ15Ν≤0‰) and non-fixers which are used as a reference. During the 1998 growing season, four leaf samplings were conducted in an upland grassland of Northern Greece and δ15Ν values were determined in Trifolium repens and 6 co-existing species (Poa pratensis, Lolium perenne, Festuca valida, Taraxacum officinale, Plantago lanceolata, Achillea millefolium) which served as references. Festuca valida, Taraxacum officinale and Achillea millefolium were found to be appropriate reference species, since they had significantly different δ15Ν values compared to Trifolium repens and the N2-fixation determinations calculated using these values were acceptable (positive). As well as, the average of δ15Ν values of all non-legume species gave acceptable N2-fixation percentages. The percentages of N2-fixation determined for the four reference species (Festuca valida, Taraxacum officinale, Achillea millefolium and the average δ15Ν values) did not differ significantly. Significant differences were found for N2-fixation percentages between sampling dates. The reliability of the method of 15Ν natural abundance is high when the percentages of N2-fixation determined are high (>70%). In our study, for all reference species (Festuca valida, Taraxacum officinale, Achillea millefolium and the average of δ15Ν values) and samplings, N2-fixation was higher than 75%, which reveals that the use of 15N natural abundance method was pertained.
