Methods for estimating leaf area in forages species
Leaf area is an important variable for ecophysiological studies since it plays an important role in light interception, photosynthesis, water and nutrient use, crop growth and development. Moreover, understanding the properties of the leaf area could provide valuable information regarding cultural practices such as irrigation, fertilization, pruning etc. Nevertheless, determination of the leaf area is not an easy task, and there has been a great variety of methods developed. We present the most frequently used, direct and indirect techniques to estimate leaf area in forage species, and their advantages and disadvantages are discussed. Direct methods usually require removing leaves and then determining the leaf area; these methods are destructive and require adequate, potentially expensive, equipment. Indirect, non-destructive, methods are user friendly, less expensive, and can provide accurate leaf area estimation. The latter methods offer reliable and inexpensive alternatives in horticultural experiments and may be also used to determine the relationship between leaf area and plant growth rate. However, selection of the most appropriate method for leaf area estimation should be based on experimental goals and available equipment.
Landscape composition of rangelands within the “Natura 2000” habitat network in Greece
Rangelands constitute an important part of the habitat type ecological network “Natura 2000” of protected areas in Greece. In this paper, the five rangeland types present in this network, namely grasslands, phrygana, shrublands, forest ranges and wet grasslands, were identified and analysed some aspects of their landscape composition along four altitudinal zones. According to these results, 57 rangeland habitat types can be found in Greece, covering an area of 1,169,403 ha or 47% of the total mapped area. The most common rangeland types are those where woody plants are dominant, covering about 65% of rangelands. Diverse mosaic pattern is evident in all altitudinal zones but it prevails in the middle altitudes, while rangelands above 1200 m seem to be more homogenous composed of extensive shrublands. Forest ranges make the most fragmented landscapes in all altitudinal zones except above 1200 m where their presence is relatively limited.
Thermophilous grasslands of southeastern Europe
A large proportion of grasslands found in southeastern Europe are thermophilous in the sense that they grow in the low elevation zone and are dominated by the warm season perennial grasses Chrysopogon gryllus and Dichanthium ischaemum (=Bothriochloa ischaemum). In fact, they are transitional between the typical Mediterranean grasslands dominated by annual grasses and the temperate grasslands dominated by perennial cold season grasses. In this paper, their distribution as well as their phytosociological, ecological and economic aspects are reviewed and discussed. They are distributed in the Quercetalia pubescentis zone, mostly in the Ostryo-Carpinion orientalis subzone, in large openings and represent the last stage of grassland colonization after the destruction of forests. Phytosociologically, these grasslands are classified in many associations or plant communities (e.g. Chrysopogono-Caricetum humilis, Thymo urumovii–Chrysopogonetum) mainly of the Festucetalia valesiacae order (Festuco-Brometea class), but also in other orders and classes such as Helianthemetea guttati, depending on their floristic composition. They are very productive grasslands with high grazing value for livestock. Because of their high plant diversity and the threat of vegetation succession, these semi-natural grasslands are under protection status in several areas (e.g. “Ponto-Sarmatic steppes”, which are a priority habitat type under the EU Directive 92/43).
Distribution of Leguminosae taxa in habitat types of northern Greece
The plant family of Leguminosae includes many taxa of high economical and ecological value. The present paper aims at the investigation of Leguminosae taxa distribution in habitat types of northern Greece. Published data from floristic and vegetation works, as well as, unpublished field data were used to explore their habitat preferences. Results revealed that Leguminosae taxa found in salt meadows and dunes are few; most of them occur in (sub-) continental forests and grasslands: a) a group including taxa growing at lowland grasslands (e.g. Trifolium cherleri), b) another group comprised of taxa occurring at higher altitudes and mainly at subalpine grasslands (e.g. Anthyllis montana ssp. jacquinii, Onobrychis montana ssp. scabrica), c) a third group representing taxa found mainly in thermophilous scrubs (e.g. Calicotome villosa, Anthyllis hermanniae), d) a fourth group concerning taxa occurring in azonal forests (e.g. Gleditsia triacanthos, Robinia pseudoacacia), and e) a fifth group of taxa found in submediterranean and subcontinental forests (e.g. Vicia grandiflora, Trifolium alpestre, Lathyrus vernus,). Some species have a broad niche breadth, such as Trifolium fragiferum, T. campestre and Lotus corniculatus, occurring in a high variety of habitats.
Orchid species distribution in rangelands of Epirus, Greece
The orchid family (Orchidaceae L.) is one of the richest plant families in the world, including at least 24,000 species and subspecies. In Greece the number exceeds 200 taxa, while the endemics are 50 or more. These numbers often change, as new species are described or others considered until recently as endemics in Greece, are recorded in neighbouring countries. This research carried out at various rangeland types of Epirus region. A total of 58 species and subspecies were identified. The majority of taxa belong to the genera Ophrys and Orchis. The results revealed that the highest number of taxa (37) exists in forest openings and silvopastoral systems especially of oak trees, followed by 25 taxa in grasslands and 22 taxa in open shrublands (evergreen broadleaved species). The lower orchid richness, 17 taxa, was found in the phryganic ecosystems. As a conclusion, rangeland ecosystems of Epirus are significantly rich in orchids and their conservation, especially in oak silvopastoral systems, seems to be of particular importance for the maintenance of orchid diversity.
