Pollen assemblage differences of northern and central Greece grasslands: some notes on grazing
Vegetation and pollen trap data, obtained from ‘open’ areas and subalpine grasslands of Mts Pieria (north-central Greece) and Mt Tymfristos (central Greece), are compared. The highest achievable pollen taxonomic resolution is implemented in both pollen and vegetation taxa. Signs of previous intense human impact are still evident in both areas as indicated by the presence of various ruderal species. A number of local pollen taxa e.g. Daphne, Marrubium, Astragalus, Scleranthus, Eryngium, Herniaria, Centaurea jakea differentiate the pollen assemblages of Tymfristos traps from those of Pieria. The different dominant forest vegetation of the two sites diversifies further the pollen assemblages of their traps. Indicators of local (around the traps) grazing e.g. Ranunculus acris- type Crepistype, Cirsium/Carduus, Rubiaceae, are recorded in all traps. Other pollen types like Plantago lanceolata- type, Artemisia, Rumex acetosa, Urtica, Chenopodiaceae indicate human activity (forest clearings/human settlements and grazing) in a regional scale.
Single or mix mycorrhizal fungi inoculum? The potential role of different mycorrhizal fungi
Seeded plants of several grass species were grown in a mix or single culture for a 3-year period, at a site situated inside the Taxiarchis University Forest (Chalkidiki, northern Greece) with sub Mediterranean climate. One hundred 10-litres in volume containers were filled with mix soil from B and C horizons with sandy loam texture and low available phosphorus. The soil parent material was para-gneiss. Ten replicated treatments were inoculated with Gigaspora margarita BEG 34, ten with Glomus intraradices BEG 144, ten with Acoulospora longulata BEG 8, ten with a mixture of the BEG isolates used and ten with a mixture of indigenous species. Plant tissue analysis suggested that accelerated growth occurred after mycorrhizal application. However, significant variations on growth were observed at different fungal treatments and seasons. It is suggested that variations on growth could be explained by differences on the ability to access phosphorus and the limited phosphate source at the soil used, the inter-fungal interactions and the functional compatibility with the host plant.
Herbage production and number of plant species in subalpine meadows of two mountains with different geological background and soil characteristics in Northern Greece
In this study, the effect of soil macro-nutrient concentrations on herbage production and number of plant species in subalpine meadows of Jenna Mountain and Belles Mountain were investigated. In each study area, 9 sampling plots (4×4 m) were placed and herbage production was collected, and the number of plant species was recorded monthly from May to September 2011. The texture of soils was determined, and the concentrations of organic matter, total Nitrogen, Phosphorus, exchangeable potassium were measured. A total of 129 species were recorded on Mt Jenna while 161 species were recorded on Mt Belles. The average herbage production was significantly higher (p<0.05) on Mt Belles. A positive correlation between herbage production and soil N, K and OM were observed on Mt Belles while no such correlations were observed on Mt Jenna. On both mountains there was a negative correlation between the number of species and herbage production. Results from soil analysis showed that the concentrations of total N and OM were higher (p<0.05) in the 0- 10 cm depth compared to the 10-20 cm depth. Exchangeable K was higher (p<0.05) on Mt Belles, however total N was higher (p<0.05) on Mt Jenna. It seems that the climatic conditions as well as the geological background may have affected these findings.
Variability in responses of animal groups to grassland restoration
Understanding the diverse responses of animal groups to grassland restoration is vital for restoration planning. Here we summarise responses of seven animal taxa (orthopterans, bees, carabid beetles, spiders, amphibians, birds, mammals) to grassland restoration in Hortobágy National Park (E-Hungary). Species richness did not vary but abundance increased with time in orthopterans. Carabid species richness and abundance, and spider and bird abundance decreased after a peak in Year 1 after restoration. Both species richness and abundance of amphibians increased after Year 2. There were no changes in species richness and abundance of bees and small mammals and in the species richness of spiders and birds. Our results show that the responses to grassland restoration can greatly vary among animal taxa. Trends in several arthropod taxa could be explained by vegetation changes, whereas vertebrates showed fluctuations due to factors other than restoration per se.
Cutting and water deficit effect on water use efficiency of forage species
Water use efficiency (WUE) is a widely used concept connecting different processes directly or indirectly related to biomass production and water used. The different ratios of WUE proposed in the literature are based on agronomical, ecophysiological approaches or combination of them. Water deficit influences plants by closing the stomata, indirectly reducing photosynthesis, leaf extension and growth. Moreover the reduction of transpiration due to stomatal closure is greater than photosynthesis. Furthermore, water deficit changes root growth and distribution, therefore modifying the plant ability to extract water from the soil. The relationship between water deficit and WUE is controversial. Many researchers report higher WUE under water deficit, while others lower. On the other hand, cutting parameters, such as timing, frequency and intensity affect the values of WUE, as they affect the harvestable biomass and evapotranspiration. Nevertheless, the absolute values of WUE vary markedly depending on plant, soil, climatic factors and management practices. Regardless of the method used, WUE could still be considered as a useful selection criterion for superior performance, particularly, in a dry environment.
