Messara, GR

Messara, Greece: Description of site and main causes of degradation

2014-11-06T09:45:14+00:00

Authors:	Tsanis, I. K. and Daliakopoulos, I. N.
Coordinating authors:	Tsanis, I. K. and Daliakopoulos, I. N.
Editor:	Brandt, C. J.
Source document:	Daliakopoulos, I. and Tsanis, I. (eds) 2014. Historical evolution of dryland ecosystems. CASCADE Project Deliverable 2.1. CASCADE Report 04. 126 pp.

Description of the study site

General information

The Messara basin encompasses an area of 611 km² located in the central-south area of Crete, about 50 km south from the Prefecture capital, Heraklion, and constitutes the most important agricultural region of Crete. It is also the site for the Minoan palace of Phaistos and the Roman city of Gortys. The Messara Valley has remained rural with a small population of almost 45,000 inhabitants. In the Messara valley, the surrounding hills and mountains as well as elements such as Phaistos ruins, are strong landmarks, among the many that make Crete famous for its landscape and nature. Although human induced changes have affected the landscape, agriculture predominates in the area, thus being a staple to the local economy. The Messara Study Site for CASCADE is comprised of plots around the villages of Pompia and Perion.

" data-placement="top" data-content=" Messara Study Site, Crete location" title="">

Topography

Messara comprises of a plain with East-West orientation, about 25 km long and 5 km wide, with a total area of 112 km², hedged with mountains on the north and south sides. The basin can be conceptually divided in two hydrological catchments: the Geropotamos-Festos and the Anapodaris-Xarakas. The geomorphological relief is typical of a graben formation and the surface drops within 15 km from 2,454 m in Psiloritis Mountain to 45 m at Festos. The Geropotamos River with a westward direction and the Anapodaris River with an eastward direction drain the homonymous catchments. The catchment area of the northern slopes is 160 km² while the southern slopes constitute a catchment area of 126 km². To the north, the divide varies from 1,700 to 600 m from west to east, with the highest point being part of the Ida mountain range (peak at 2,540 m). The Asterousia mountain chain lies in the south and rises 600 m in the west to 1,200 m in the east. The Messara Valley covers an area of 398 km² within the watershed, with a mean altitude of 435 m. Charakas catchment lies at the east part of the Valley and Geropotamos River flows to the west, forming the catchment of Phaistos, where it meets a constriction at an outlet 30 m.

Geology and Soils

The plain area of the two catchments hosts the largest alluvium aquifer system of the island, with an area of 216 km². Topographically, the Messara basin is characterized by a flat basin morphology modified by river terraces and alluvial fans. The Messara valley, defined by the inner Messara graben zone, is an alluvial plain mainly composed of quartenary deposits. The plain is covered mainly by quarternary alluvial clays, silts, sands and gravels with thickness from a few meters to 100 m or more. The soils in the plain belong to the order of Entisols. In the north, the Valley is bordered by a hilly area of silty-marley Neogene formations, whereas in the south schist and limestone Mesozoic formations are dominant.

" data-placement="top" data-content=" Simplified hydro-geological map of Messara basin (source: IGME)" title="">

" data-placement="top" data-content=" Soil groups according to the FAO classification in the study site (source: JRC)" title="">

" data-placement="top" data-content=" Categories of soil materials (WRB) in the study site (source: JRC)" title="">

Dominant soils in the basin are cambisols (north slopes), luvisols (south and north-east slopes) and fluvisols (center of the valley). Calcaric soils are dominant across the basin with the exception of the east part where soils are chromic.

Land Use

About 250 km² of the total valley area of 398 km² are cultivated. The main land-use activity is olive growing (about 175 km²) with some grape vine cultivation (40 km²). The remainder of the cultivated land is used for vegetable, fruit and cereal-growing as well as for livestock grazing (higher grounds). The vines and about half of the land area under olives are drip-irrigated. For the period of 1984-1997 cereals covered an area of 25 km², vegetables 16 km² and grape vines 26 km², while the area of the watered olive trees increased from 38.5 km² in 1984 to 110 km² in 1997. The study site shows little change in terms of landuse since at least the 1940s. The only significant transition can be observed at the Pompia area, where “open spaces with little or no vegetation” actually represents burned area. From a total of 2.1 km², about 0.8 km² are within the Pompia Study Site and since then have been fully recovered and transformed to scrublands. Actually changes not clearly documented in CORINE include the intensity of exploitation for each landuse, as well as the extent of sealed and urban areas.

" data-placement="top" data-content=" Land use in the study site (source: CORINE, JRC)" title="">

" data-placement="top" data-content=" Mean monthly precipitation (blue) and mean annual precipitation (green) measured at Pompia" title="">

" data-placement="top" data-content=" Mean monthly temperature (red) and mean annual temperature (blue) at Pompia derived from the E-OBS dataset and corrected for bias" title="">

Climate

Messara Valley’s climate is classified as dry sub-humid and its hydrological year can be divided into a wet and dry season. Crete has a typical Mediterranean island environment with about 53% of the annual precipitation occurring in the winter, 23% during autumn and 20% during spring while there is negligible rainfall during summer. Although the Valley receives on average about 650 mm of rainfall per year, it is estimated that about 65% is lost to evapotranspiration, 10% as runoff to sea and only 25% goes to recharging the groundwater store. Rainfall increases with elevation from about 500 mm on the plain to about 800 mm on the basin slopes while on the Ida massif the annual precipitation is about 2,000 mm and on the Asterousian Mountains it reaches 1,100 mm. The maxima of mean monthly precipitation generally occur during winter with the exception of central south part of Crete (South of Messara Valley) where the maximum mean monthly precipitation is in November and September. For the available record, precipitation shows no significant trend over time and remains stable at an annual rate of 504 mm.

The average winter temperature is 12 ºC while in the summer it is estimated at 28 ºC. For the available record, temperature remains stable at an annual mean of 16.6 ºC. Relative humidity in winter is about 70% whereas in the summer it reaches about 60%. Pan evaporation is estimated at 1,500 ± 300 mm per year while the winds are mainly north-westerly. The potential evaporation in the area is estimated at 1,300 mm per year and for the study site it is estimated at 1,575 mm.

Hydrogeology

The plain area of the two catchments hosts the largest alluvial aquifer system of the island, containing several aquifers and aquicludes of complex distribution and properties. The inhomogeneity of the plain deposits gives rise to great variations in the hydrogeologic conditions even over short distances. Soil porosity decreases with depth below surface in a range of 0.05–0.13. The Neogene sediments and flysch are both characterized by a relatively high runoff while a small part of the mountain area is occupied by karstic formations characterized by negligible runoff and high infiltration. Groundwater is an important natural resource of the Messara Valley, as it is the main source of irrigation and domestic supply. Groundwater levels are highest in March or April with long recessions until recharge occurs in winter. Lateral groundwater outflow is small compared with the vertical groundwater outflow. In the area, 845 registered wells operated in 2004 and in 2007 their number was estimated at 1,400 causing a drop in the water table of as much as 45 m due to overexploitation. During wet years there is high recharge and low discharge, while the opposite occurs during dry years. It is also obvious that during the 1990s the discharge increased rapidly due to the intense groundwater withdrawal for irrigation purposes.

" data-placement="top" data-content=" Precipitation and groundwater recharge and discharge for the period 1981-2002 (source: Tsanis and Apostolaki, 2008)" title="">

Water quality

Concentrations of physico-chemical parameters, heavy metals, conventional pollution parameters, total organic carbon and phenols as well as pH and electric conductivity values of karstic aquifer groundwater samples do not exceed the parametric values given by European Community. In shallow alluvial aquifers, water quality parameters, such as nitrate and sulphate, evidencing contamination sources such as fertilizers, wastewater disposal sites and olive-mill factories were estimated for groundwater samples contents over the drinking water guidelines given by Dir. 98/83/EC. Notwithstanding the fact that during the last 50 years pesticides were used in the area, only the aminomethylphosphonic acid (AMPA) which is the major metabolite of glyphosate, was detected in the groundwater samples in values close to the parametric one. Finally, anthropogenic contamination due to agriculture, with high values of sulphate and chloride, was detected through the analysis of surface water (streamflow).

Flora

There is no doubt that with some exceptions, Crete was covered with forest before Neolithic times. Today, there is no forest left in the region but the natural landscape is dominated by scrublands, the typical Mediterranean garigue. The most common and most characteristic vegetation type in the area met today is the evergreen maquis/phrygana. It is found predominantly from 0 to 600 m, but may reach about 1,000 m. Two major units are recognized: a community with Pistacia lentiscus and Ceratonia siliqua is found in the lower zones and the coastal plains, always together with Olea europaea and Quercus coccifera,with Q. ilex, limited to altitudes between 300 and 1,000 m. As many natural species in the area provide free fodder, especially in overgrazed areas such as the study site, the less palatable / poisonous plants such as Urginea maritima often survive and dominate the landscape.

" data-placement="top" data-content=" Ceratonia siliqua (photo: Daliakopoulos)" title="">

" data-placement="top" data-content=" Pistacia lentiscus (photo: Daliakopoulos)" title="">

" data-placement="top" data-content=" Olea europaea (photo: Daliakopoulos)" title="">

" data-placement="top" data-content=" Quercus coccifera/Q. ilex (photo: Daliakopoulos)" title="">

The Messara landscape has been in cultivation for thousands of years, leading to 30% of the flora of Crete being linked to agriculture and around 200 species being imported with agricultural systems from abroad. Two main agro-ecological zones occur in the region: the hilly zone, surrounding the plain, and the plain. Each zone displays different agro-ecological characteristics but also interacts with the other to the degree that it affects environmental variables such as water and fodder availability, soil preservation, fire hazard, etc. Since 1980, the marshes of the Messara valley have also been transformed to cultivated land.

" data-placement="top" data-content=" Average percentage frequency of selected shrubs and herbaceous species along transects for 5 locations in Asterousia and 8 locations in Messara (source: adapted from Watrous et al., 1993)" title="">

" data-placement="top" data-content=" Historical evolution of NDVI through time corrected for bias using value from LandSat imagery (black circles)" title="">

A synoptic view about vegetation health and the associated function of ecosystems can be derived from analysis of archival and on-going sequences of NDVI, an initial exploration of which has shown no significant trend since the 1980s.

Fauna

The fauna in Crete is the result of a severe human-induced selection in favour of species belonging to the geographic and cultural universe of the human groups that immigrated to the islands, within which domestic livestock predominate. Rational grazing, the model developed for several millennia in Crete, was harmonized with the local biodiversity and contributed to its protection by preventing abandonment. The cultivation of olive trees on agricultural lands (lowland areas of Crete) has resulted in the gradual destruction of the natural environment and biodiversity. Today, the fauna has 2,500 members 180 of which are endemic. The dominant pastoralism model regarding hilly - mountainous regions (foothills) involves free grazing of sheep and goats. Traditionally animals were grazing in the fields and in the olive groves and were used for transportation and land cultivation.

Studies on grazing-capacity (number of animals that can be supported per grazed area) are not available in Crete, thus causing pastoralists to increase herds to numbers that cannot be sustained by the pastures. When the nutritional needs of the animal population are not met, ultimately the shepherds are forced to deal with fodder costs. The use of fodder imported to Crete (mainly corn) forces animals to eat anything dry, as they have a cellulose deficiency, without which their digestion cannot be sustained. For this reason they are often forced to eat tree bark etc. to meet their nutritional needs, thus causing even greater damage to the natural vegetation.

" data-placement="top" data-content=" Flock of sheep passing through the agricultural area (photo: M. Grillakis)" title="">

" data-placement="top" data-content=" Livestock (sheep and goats) population in the area of the study site (source: based on data from Greek National Statistical Service)" title="">

Animal population in Crete reached 2,200 million in 2000, and is now estimated to be around 1,700 million. In recent years (2007 to present), a 30% reduction of the animal population took place due to the doubling of the fodder price. On average, each producer has about 200-250 animals of which about 20% are goats. Livestock population in lowland, more urbanized and more touristically attractive areas is decreasing while highland population is increasing. In recent years, chances in livestock population are marginal.

Vegetation – soil system

The selected vegetation in the study site is Hyparrhenia hirta which is native to much of Africa, the Mediterranean and Eurasia. The plant is a densely tufted, annual, or more usually perennial, grass, 0.3–1.5 m tall with awned, hairy, grey green spikelets carried in many pairs of racemes, in an open panicle and tough, dense bases sprouting from rhizomes. Each raceme has a leaf-like bract at the base and the inflorescence atop the wiry stem is a panicle of hairy spikelets with bent awns up to 3.5 cm long. The grass can grow in a variety of habitat types, in dry conditions, heavy, rocky, eroded soils, and disturbed areas. It grows on a wide range of soils from shallow sands to clays and ﬂoodplains, clay soils, dolerite hills, disturbed and shallow soils. Grasses like Hyparrhenia hirta show a marked increase in flowering after fire events, but the herbaceous species are soon replaced by woody plants. Coolati grass is a C4, usually perennial plant, however under good nitrogen conditions and in a Mediterranean environment it is not expected to be more productive than the cool season C3 plants. Along a transect across the Western Messara, the average percentage frequency of Hyparrhenia is 16.0% and 21.2% at Asterousias Mountains and Messara Valley, respectively.

The soil in the study site is of average composition and is characterized as loamy and calcareous. It contains 30-50% CaCO3 and moderate to low organic matter (0.8-1.2%). pH is neutral to slightly alkaline, between 7.6 and 8.5. This soil belongs to Luvisol. The mixed mineralogy, high nutrient content and good drainage of these soils make them suitable for a wide range of agriculture, from grains to orchards to vineyards. Luvisols form on flat or gently sloping landscapes under climatic regimes that range from cool temperate to warm Mediterranean.

" data-placement="top" data-content=" Provisional soil texture assessment in the study site" title="">

Socioeconomic status

The agricultural lands in the mountains of Greece are characterized by a decreasing population density due to socio-economic and political factors. This land abandonment, as a result of outmigration and off-farm employment, leads to less productive lands that are susceptible to environmental degradation. In Messara, fields are usually scattered around the villages with the average farmer owning about 5-10 plots with an average farm size of 3.5 ha, while the average distance between the village and the plots is 3-5 km. This unprofitable system that obliges farmers to commute partly exists due to the Cretan heritage system, according to which all children receive a part of the farm, and partly due to the unwillingness to exchange fields. The island customs discourage land consolidation thereby leading to increased fragmentation and declining farm size. This custom can explain the high number of small land-parcels prevailing in the study area. Furthermore, most grazing grounds are not clearly defined as they can be both private and public and many make use of the law about acquisitive prescription allowing them to take ownership of land after 20 years of undisputed use. Both land tenure and taxation system appear to play an important role in the farm size. The cultural value system dictates maintaining the land ownership even during the absence of the owners who often return to cultivate them after retirement.

Nowadays, Cretan agricultural practices mainly include monocultures, with olive groves and vines both in the hills and in the plain. Vine growing has become quite challenging, as it comprises intensive labour in contrast with the low prices in the market. Although excellent wines and raisins are produced, harsh global market competition, management and marketing problems, as well as the current economic crisis, cause profits to reduce significantly. Furthermore, olive oil is the main product of the island and at the moment the most profitable crop of the agricultural sector. In contrast to fresh products, olive oil does not need fast transport, but its price is also lowered on the saturated European market under the pressure of economic crisis while marketing problems have started to appear as well. This single-commodity approach makes olive growers vulnerable to market fluctuations. Economic crisis and the inability of pastoralists to purchase fodder have resulted in the abandonment of pastures and as a result the problem of overgrazing is indirectly solved with adverse effects.

Timeline of events

A brief event timeline shows the most important changes and milestones that occurred in the natural and social environment of Messara basin.

" data-placement="top" data-content=" Event timeline for the Messara basin since the 1970s" title="">

Main Causes of Land Degradation

Human induced Drivers

Agricultural policy and excessive withdrawal of water: In Crete, as in the rest of Greece, high profitability of irrigated farming has led to over-exploitation of water resources. The amount of water allocated for irrigation is estimated to be 82% of the total consumption. In general, water consumption has increased by more than 4% per year. Most of the total water consumption is used in agriculture for the irrigation of olive groves, vineyards and vegetables and the European Common Agricultural Policy (CAP) has significantly affected cropland areas and land use types. In Crete, many marginal areas under natural vegetation were cleared and olive groves have been planted. These areas become particularly vulnerable to erosion due to inadequate soil protection and reduction of infiltration rates which follows loss of organic matter content and soil structure decline. Widespread olive production in steep hilly areas in combination with the lack of water and grazing has resulted in desertification problems.

The main source of irrigation water in Messara is groundwater as there is little surface water flow outside the winter months. Groundwater is the key resource controlling the economic development of the region, and it comprises a component of the environment under siege as water demand is increasing with time. The increased demand of water, either for domestic or agricultural use, cannot always be met, despite adequate precipitation. Water imbalance is often experienced, due to temporal and spatial variations of precipitation, increased water demand during summer months and the difficulty of transporting water due to the mountainous areas. A characteristic example of groundwater over-exploitation is the western part of Messara Valley. Lately, there have been growing concerns over the possible depletion or deterioration of the groundwater quality in the basin due to intensive pumping beyond the safe yield of the basin.

In 1970, two irrigation systems were constructed in the area as prototypes for a future extensive network. At the time, the average groundwater level fluctuation over the hydrological year was about 3 m, which for a mean porosity of 0.05 for the clayey phreatic aquifer of the Valley gives an average recharge of 150 mm per year. Measurements have shown that the groundwater level at that time was about 5 m below surface and the maximum rate of withdrawal was 5 Mm³ per year with discharge rates as high as 300 m³/h. Then, the average surface discharge out of the Valley was 20 Mm³ per year which corresponds to a loss as runoff about 50 mm per year.

In 1984 an extensive network of groundwater pumping stations was established in Messara Valley, causing an increase in the rate of groundwater withdrawal and a dramatic drop in the groundwater level of about 20 m. Since the groundwater irrigation network was installed, the groundwater level has on average decreased by about 2 m per year as what used to be non-irrigated cultivation of vines and olive trees was transformed to drip-irrigated cultivation. The end effect is that about 660 mm of water per year, or about an average 2 mm per day, is lost from the Valley (Vardavas et al., 1997). Although the amount of water required for irrigation of olive plantations is relatively low compared to arable crops, there has been a dramatic over-exploitation of aquifers accompanied by water quality deterioration. In addition, regional development, infrastructure, spatial planning policies and the implementation of Integrated Mediterranean Programmes constitute the factors that have considerably affected the exploitation of natural resources. Finally, the sequential occurrence of dry years in the 1990s has led to more intensive pumping to meet the irrigation demands. As a result, in 2000 the groundwater level was 45 m below the surface. During the last three years, the runoff of the Geropotamos River is close to zero due to the percolation rate increase.

Overgrazing: Free-range livestock can, over time, degrade rangelands due to overgrazing. The rate of degradation depends on the density of the livestock population and the restoration rate of the natural flora. The relationship of those rates can be used as a tipping point index. The direct effects of the introduction of domestic grazers on native faunas since prehistoric times are well described for the Mediterranean islands, where original faunas have been affected by species extinction and introductions promoted by humans. The Asteroussia and Psiloriti mountains of Crete represent characteristic cases of degradation caused by intensive grazing and fires set by shepherds. Soil erosion is apparent in many cases, and areas that appear irreversibly degraded (desertified) are often found. The grazing areas of the Psiloriti Mountains in central Crete extend into higher altitudes of sub-humid and humid Mediterranean climates (1,000-2,000 m). In areas often covered with matorral or mountainous phrygana, relict kermes oak forests (Quercus coccifera) are still found. Moreover, in this region grazing pressure has significantly increased. Statistical figures for some of the mountainous communities show an increase of the total number of sheep and goats by more than 200% between 1980 and 1990. Nevertheless, it has been observed that flora biodiversity can be fully restored by applying rational grazing on degraded areas when fertilization and fence application for at least a month take place. The implementation of such a program requires the removal of animals for a period of 2-3 years, after which the site can be grazed at carrying capacity.

Natural Drivers

No prolonged drought events have taken place throughout the available record and the area is mostly under normal conditions. Nevertheless, especially extreme drought conditions took place in the years 1992–93. Drought phenomena under mild conditions were also observed during the period 2000–02. The sensitivity of drought to the precipitation variability rather than the long term average is depicted in the SPI results. Regarding the Aridity Index, the area displays stability with a slight decreasing trend. This long term trend might have been significant but was overturned by the relatively large precipitation amount received in 2002 (905 mm). The area generally belongs to the semi-arid bracket with only four years crossing over to a more arid character. Nevertheless, this tendency to arid climate is possibly occurring at a higher frequency after the 1980s.

" data-placement="top" data-content=" SPI 48 estimated for the period 1963-2002 for the area of Pompia" title="">

" data-placement="top" data-content=" Aridity estimated for the Pompia Area" title="">

Indirect causes

Greece joined the EEC (European Economic Community) in 1981 and Greek agriculture became subject to the Common Agricultural Policy (CAP). Up until 1992, the aim of the CAP was to increase production, and to provide cheap rural products accompanied by reasonable rural incomes. The consequences of the CAP in Greece were the intensification of agricultural production, extensive mechanisation of crop production, creation of monocultures, such as cotton and olive trees, large surpluses of some products, the disappearance of some unique Greek plant varieties which were replaced by hybrids, and the loss of the rural balance with its self-sufficiency in agricultural products. Greek farmers have re-orientated crop production towards the globalised market and Greek agriculture is no longer based solely on the needs of the country or the European Union. This has resulted in the orientation of Greek agriculture to three main crops: olives, cotton and tobacco. As a result, the country has simultaneously lost its self-sufficiency in products such as cereals, fruits, and vegetables. Crete has not been an exception to this.

Rural migration has also had a significant impact on cropland and land management practices. Large scale migration from rural to urban areas took place in Greece after the 1950s and since then rural population has continued to decrease. As a result, land was either abandoned or rented. These conditions facilitated the over-exploitation of rural land from the few remaining farmers who often adopted harsh methods, such as uncontrolled burning of shrubs, otherwise condemned by neighboring users. At the same time, the total population of Crete has increased in the last four decades. The rate of increase was especially high in the area of Heraklion, putting significant pressure on land for transformation from agriculture to residential or industrial uses. Apart from urbanization, mass tourism has also put a pressure on the Cretan landscape in the last few decades. The total number of tourists in Crete exceeds 2 million per year and this number may double by 2025. As a result and a means to improve their financial profile, in less productive areas, particularly along the coast, farmers have sold their land to developers for the construction of tourist infrastructure.

" data-placement="top" data-content=" Changes in urban and rural population between 1985 and 2010 in Greece (source: based on data from Greek National Statistical Service)" title="">

The CAP, through its structural policies, supported an adequate income to farmers, contributing to the development of regional economies and reform of landscapes, particularly in less favoured areas. In addition, subsidies allocated under the CAP accelerated the intensification and specialization process in agriculture. Subsidies, allocated based on the area cultivated encouraged farmers to keep highly degraded land under cultivation, or to expand cultivation into marginal areas, even with low crop yields, thus accelerating erosion and land degradation. On the other hand, the lack of coordination between organizations (development agencies) and state services responsible for land management as well as knowledge gaps, have been liable for the lack of Cretan landscape policy application. Organized efforts from the EU strive to bridge these shortcomings in management, infrastructure and knowhow but there is still a long way ahead.

Messara, Greece: Drivers of change

2016-01-25T10:57:41+00:00

Authors:	Tsanis, I. K. and Daliakopoulos, I. N.
Editor:	Jane Brandt
Source document:	Daliakopoulos, I. and Tsanis, I. (eds) 2014. Drivers of change in the study sites. CASCADE Project Deliverable 2.2. CASCADE Report 06. 59 pp.

In the Messara Study Site, the succession of dry years, combined with mismanagement in the resources depletion intensity (e.g. water abstraction, grazing) have caused marked breaks in the greenness trends. A significant disturbance takes place two years after the manifestation of the minimum SPI48 value, in 1995. After the end of this pronounced drought, the deseasonalised NDVI signal increases following a stabilization of the SPI48. Regarding the seasonal component of the NDVI, few changes occur between periods 1985-1991 and 2000-2003. The small dependence on climatic factors can be attributed to the high degree of agricultural activities within the investigated location. Here, water resources and optimal growing conditions for vegetation nearly all year long and can account for the relatively stable NDVI during summer months.

" data-placement="top" data-content=" NDVI Seasonal component differences for the periods before and after trend shifts for the Messara Study Site." title="">

" data-placement="top" data-content=" Bimonthly NDVI, broken down into seasonal and deseasonalised components, against SPI48 for the period 1982 – 2003 for the Messara Study Site." title="">

In order to investigate the sensitivity of the method, an alternative area with a smaller proportion of agricultural land versus graze land within the Messara Study Site is also investigated. At this alternative location, vegetation suffered at a greater degree during the 1993 drought. Indeed, this location shows signs of degradation as early as in 1989, possibly due to the lower resilience or the reduced vegetation cover ecosystem. In this case vegetation manages to recover after 1997, however it is possible that the time required for recovery increases as aridity and water stress drive the system to its limits.

" data-placement="top" data-content=" Bimonthly NDVI, broken down into seasonal and deseasonalised components, against SPI48 for the period 1982 – 2003 for an alternative location within the Messara Study Site." title="">

Note: For an overview of the historical drivers of change and their analysis in all study sites see »Drivers of change in the study sites.

Messara, Greece: Structural and functional changes

2016-01-14T11:29:19+00:00

Authors:	Alejandro Valdecantos and Ramón Vallejo (CEAM) with input from study sites
Editor:	Jane Brandt
Source document:	Valdecantos & Vallejo. (2015) Report on structural and functional changes associated to regime shifts in Mediterranean dryland ecosystems. CASCADE Project Deliverable 5.1.

An area under pressure from grazing

The degradation pressure in Messara resulted in a trend to reduce total plant cover under the highest pressure level. Both Reference and Semi-degraded ecosystems showed percentages of plant cover slightly below 80% while this variable dropped to 62.5% in the highly degraded sites. Sarcopoterium spinosum was the most abundant species in the Reference state, with 13.3%, followed by Salvia fruticosa and Crepis conmutata that both presented cover values below 10% . In the Semi-degraded plots, three shrubs were the most abundant species: Thymbra capitata, Crepis cretica and S. spinosum, with cover percentages of 18.0, 14.5 and 11.6%, respectively. Avena sp also showed cover values above 10%. Thymbra capitata was the most common species also in the Degraded sites, but with lower cover percentages than in the Semi-degraded (14.5%). This was the only species that showed cover values above 10% in the highly Degraded plots. The Reference and the Degraded were the situations that shared the higher number of species (19) while the Semi-degraded showed lower number of common species with the other two ecosystem states (12 and 13 with the Degraded and Reference, respectively). However, the PCA conducted on the specific plant cover data (42.0% of explained variance with the two first axis) showed that the plots of the two considered degradation states are closer than with the undisturbed ones. The three Reference plots showed high variability regarding specific plant cover as the only well-represented species in all three plots was S. spinosum (17.7, 12.1 and 10.1%). One of the plots showed a high percentage of Avena sp (20.7%) and another one was rich in Salvia fruticosa and Calicotome villosa (26.8 and 12.6%, respectively). These species were almost absent in the other two plots. Olea europaea, S. furticosa, Gladiolus italicus, Ononis sp, Phagnalon graecum, C. villosa and Leontodon tuberosum were positively extracted on PC1 (eigenvalue ≈ 0.9) while Hyparrhenia hirta was the species with higher positive weight on PC2 (eigenvalue = 0.881).

" data-placement="top" data-content=" Total plant cover in the Reference, Semidegraded and Degraded states (left) and distribution of plots according to the two first axis of the PCA conducted on specific plant cover (right) in Messara field site. Mean and standard errors are shown in the plant cover figure." title="">

The three plant biodiversity variables showed the same decreasing trend as the grazing pressure increased. Total number of plant species was highest in the Reference state (17.7) and lowest in the Degraded plots (13.3). The Shannon-Wiener index of diversity was marginally affected by grazing (F=3.815, p=0.099) with values of 2.09, 1.63 and 1.56 in the Reference, Semi-degraded and Degraded states, respectively. Similar effect was observed in evenness with marginal significant differences (F=4.201, p=0.085) between Reference and Degraded states (0.73 and 0.60, respectively).

" data-placement="top" data-content=" Number of species (left), Shannon-Wiener Index of diversity (center) and evenness (right) in the Reference, Semidegraded and Degraded states in Messara field site. Mean and standard errors are shown." title="">

Surprisingly, the Degraded plots showed the highest values of aboveground biomass but differences were not statistically significant (F=0.774, p=0.509) as a large range of values were observed (from 9.14 to 46.72 Mg ha-¹). This fact could have been related to the higher amount of annuals in the degraded sites and the sampling time (spring). Litter and belowground biomass in the uppermost 10 cm of soil did not result neither in significant differences between pressure states but showed a trend to increase in the intermediate pressure state.

" data-placement="top" data-content=" Aboveground biomass (left), litter accumulation (centre) and belowground biomass (right) in the Reference, Semi-degraded and Degraded states in Messara field site. Mean and standard errors are shown." title="">

Interpatches in Messara consisted of bare soil and ground covered by litter or herbs and patch areas were shrubs, subshrubs and tussock grasses. The spatial distribution of vegetation showed very similar patterns in the three pressure states. There was a trend to increase the interpatch length and cover as the grazing pressure increased with more than 50% of the land of the Degraded state corresponding to source areas with an average length of 72 cm. On the contrary, the length of vegetated patches in the Reference was 122 cm as compared to 77 cm in the Degraded plots. Semi-degraded areas showed intermediate values of these features of spatial distribution of vegetation. The width of the vegetated patches was very similar in all states.

" data-placement="top" data-content=" Values of Interpatch length (up, left), cover (up, right), patch length (bottom, left) and width (bottom, right) in the Reference. Semidegraded and Degraded states in Messara field site. Mean and standard errors are shown." title="">

The stability index derived from LFA assessment showed similar values in all pressure states while there was a trend to decrease in both the infiltration and nutrient cycling indices as the pressure level increased. However, no significant differences were observed in the stability (F=0.368, p=0.709), infiltration (F=0.343, p=0.725) and nutrient cycling indices (F=0.393, p=0.694).

" data-placement="top" data-content=" Values of the Stability, Infiltration and Nutrient Cycling indices derived from LFA in the Reference, Semidegraded and Degraded states in Messara field site. Mean and standard errors are shown." title="">

The Degraded state showed a loss of most calculated ecosystem services except C sequestration. The most pronounced and significant loss was observed in the Biodiversity service that combines data from plant species richness, diversity and evenness. The standardized value of Biodiversity dropped from 0.87 in the Reference to -0.60 in the highly Degraded sites. Soil and water conservation and nutrient cycling showed similar losses with increasing the grazing pressure. In spite of aboveground biomass showed a trend to increase in the Degraded ecosystem, the observed values of litter and belowground biomass (higher in the Semi-Degraded) resulted in higher C sequestration potential in the Semi-Degraded system than both in the Reference and degraded ones. Probably changes on plant composition also affected to C sequestration. There is a trend to decrease the values of ecosystem services as the grazing pressure increases.

" data-placement="top" data-content=" Standardized values of the list of ecosystem services in Messara, as derived from combinations of the different variables acquired. Mean and standard errors are shown. Different letters show significant differences" title="">

" data-placement="top" data-content=" Losses or gains (negative and positive values, respectively) of assessed ecosystem properties in the Degraded and Semidegraded areas of the Messara field site in relation to the References. Asterisks denote significant differences between ecosystem states." title="">

Heavily degraded sites showed an increase just in one property of the ecosystems in relation both to the Reference and the Semi-degraded sites that is aboveground biomass. Positive changes in interpatch cover and length can be interpreted as a negative consequence of pressure as they increase the proportion of bare soil. Significant losses have also been observed regarding evenness and diversity as well as the size of the plant patches. However, the magnitude of losses of the Degraded areas in relation to the Reference does not exceed 40%.

Note: For an overview of the structural and functional changes and their analysis in all study sites see »Structural and functional changes.

Messara, Greece: Adaptation strategies for changing conditions

2015-06-08T11:36:54+00:00

Authors:	Cecelia De Ita, Lindsay Stringer, Luuk Fleskens, Andy Dougill, with input from study sites
Editor:	Jane Brandt
Source document:	De Ita et al. (2015) Report on stakeholder adaptation strategies in the CASCADE study sites. CASCADE Project Deliverable 8.1.

In Messara, the dates reported for changes were from around 30 years ago (~ 1984), as noted by three participants. All stakeholders mentioned human drivers of change, in terms of promoting the overuse of resources, and denouncing the use of incorrect/poor practices but also blocking positive change, as the removal of goats is not allowed. A transient land user stated that: “due to socioeconomic conditions in the area, the number of farmers escalated in the 1970s.” Furthermore, animal production started being subsidized by Greece and the EU, supporting the new farmers. As a result, the number of animals increased. Goats (vs sheep) are acknowledged as a driver of land degradation but heritage does not “permit their removal”.

The increase in grazing was felt to be motivated by high unemployment rates, while the intensification of agriculture and the change to irrigated crops, driven by subsidies, were considered as socio-economic drivers. These were said to have caused a serious decrease in the natural vegetation, wildlife and water levels.

Table: Drivers of change identified by stakeholders in Messara, Greece.CASCADiS Table

Drivers	Groups of transient land users	Sedentary land managers operating at small scale	Governmental institutions
Intensity of farming	X		X
Inappropriate subsidies	X	X
Increase in the intensity of grazing	X	X
Environmental regulations in place	X		X
Changes in agricultural practices (use of irrigation)	X	X	X
Socio-economic conditions in the area	X	X	X
Intensity of water use		X	X

The main changes to traditional forms of land use quoted by stakeholders were the changes from subsistence agriculture to monoculture olive orchards, and difficulties in grazing animals due to the destruction of the pasture and the drying up of the springs that used to serve the animals. Equally, all stakeholders mentioned that they have modified their practices in order to adapt to the changes. Sedentary land users stated that they have been seeding barley or similar crops for use as animal fodder, and using rotational grazing techniques, afforesting pastureland with Ceratonia siliqua, which is now used as fodder, combined with rotational grazing, and using water from a dam. The status of the dam is unclear as it covers part of their current needs but it is possible that the price of water is more expensive than pumping from local wells.

These trends in land and water availability are expected by the stakeholders to continue and intensify if current practices continue. Negative socio-economic consequences were expected such as the abandonment of rural properties, as well as a lack of farming succession by younger generations, property loss by young farmers and conflicts between communities. As a sedentary land user stated: “There has been an increase in conflicts in the community as farmers and pastoralists have to share the same resource (productive land). Pastoralists let the animals graze freely in the fields and that way they can destroy trees and other property.”

Table: Summary of future expectations, alternative land management options and policy/economic support required by stakeholder groups in Messara, Greece.

Stakeholder Group	Future expectations	Alternative land options	Policy required
Land users	• Total destruction of the pasturelands. • Abandonment of traditional farming and grazing practices by younger generations • Loss of farms • Increase in conflicts between farmers and pastoralists	• Subsidies allocated considering local characteristics • Development of a livestock park under a farmers’ union with specific motives and targets using modern technology. • Switch to more traditional, less invasive practices • Use of greenhouses • Increase the potential of the dams by diverting a stream from a nearby watershed.	• Changing the way that subsides are distributed • Funding for innovating entrepreneurship actions in agriculture • Support Agricultural Product Certification • Enhance education and training • Provide organized strategies and policy regarding the agriculture and livestock sector.
Governmental Institutions	• Further increases in water demand will put water resources under further pressure, thus increasing conflict among users.	• More efficient agricultural water consumption (e.g. greenhouses, drip irrigation etc.) so that water conflict is reduced	• Applying the measures decided in the Water Management Plan

The policies and interventions suggested are mostly directed towards traditional forms of land use and environmental management. The need for tailored policies to suit local needs was pointed out by all stakeholders, such as the strategy proposed by a transient land user: “It is needed to change the way that subsides are distributed, taking into account the real productivity of each farmer e.g. the amount of produced milk, cheese, meat, olive oil, wine etc., and reducing taxes and fees of transportation, so that the end price of fodder in distant areas is lower.” Investing in alternative and innovative agricultural projects was also mentioned, in the form of supporting the development of product certification, organizing producers, and improving water management by increasing the potential of dams “by diverting a stream from a nearby watershed”.

Note: For an overview results of the workshops on identifying adaptation strategies in all study sites and the concluding recommendations see »Adaptation strategies.

Messara, Greece: Restoration potential for preventing and reversing regime shifts

2017-03-21T14:27:17+00:00

Authors:	Alejandro Valdecantos (CEAM),V. Ramón Vallejo (UB), Susana Bautista (UA), Matthijs Boeschoten (UU), Michalakis Christoforou (CUT), Ioannis N. Daliakopoulos (TUC), Oscar González-Pelayo (UAVR), Lorena Guixot (UA), J. Jacob Keizer (UAVR), Ioanna Panagea (TUC), Gianni Quaranta (UNIBAS), Rosana Salvia (UNIBAS), Víctor Santana (UAVR), Dimitris Tsaltas (CUT), Ioannis K. Tsanis (TUC)
Editor:	Jane Brandt
Source document:	Valdecantos, A. et al. (2016) Report on the restoration potential for preventing and reversing regime shifts. CASCADE Project Deliverable 5.2 104 pp

Results highlights

The lack of areas with similar biophysical properties and land use histories that underwent any kind of restoration action in the past impeded to fully apply the ecosystem service protocol
The two restoration plots found included the transformation of overgrazed areas to carob tree orchards
Contrary to expected, interpatch cover and size were enhanced in the restored areas but the cover of bare soil was reduced as compared to the overgrazed degraded areas
The Melidochori approach significantly improved the infiltration index from the degraded lands while the Odigitria restoration enhanced the nutrient cycling
Plant cover, diversity and biomass data are needed to fully calculate regulating ecosystem services.

Plant cover, diversity indexes and biomass estimation (above and belowground and litter) are not yet available for the two restored sites in Messara. The assessment is therefore based just of Landscape Function Analysis variables and derived indexes.

Melidochori

The contribution of the interpatches in the Restored plot is higher than in the other three states of the ecosystem (Figure 1). The high heterogeneity of, especially, the Reference and the Semi-Degraded plots prevented significant differences of interpatch length but not of the cover. However, the total interpatch cover in the restored plot was equally distributed into litter and bare soil interpatches while both in the Reference and the Degraded plots bare soil contributed to more than 60% of the respective interpatches.

" data-placement="top" data-content=" Figure 1. Values of Interpatch length (left) and cover (right) in the Reference, Semi-Degraded, Degraded and the Melidochori Restored plot in Messara field site. Different letters indicate significant differences." title="">

" data-placement="top" data-content=" Figure 2. Values of patch length (left) andwidth (right) in the Reference, Semi-Degraded, Degraded and the Melidochori Restored plot in Messara field site. Different letters indicate significant differences." title="">

Similarly, patches were smaller, especially their average width, in the Restored plot than in the other three states (Figure 2). These data are deceptive because, in reality, there are larger patches of vegetation but not on the ground but in the canopy of the carob trees.

The combination of the soil surface assessment and spatial contribution of patches and interpatches resulted in LFA indexes not different among ecosystem states (Figure 3). Restoration improved the infiltration index in relation to the Degraded areas from 24.9% to 30.9% and was also even higher than the observed index in the Reference (29.3%). On the other hand, the highest reduction was perceived in the nutrient cycling as compared to the Reference but it was not so sharp in relation to the Degraded (from 22.2 to 19.3%).

" data-placement="top" data-content=" Figure 3. Values of the Stability, Infiltration and Nutrient Cycling indexes derived from LFA in the Reference, Semi-Degraded, Degraded and the Melidochori Restored plot in Messara field site. Mean and standard errors are shown." title="">

Odigitria

The percentage of the land corresponding to interpatches in the Odigitria restored plot was slightly lower than in the Degraded areas and rather similar to the Reference and the Semi-Degraded ones (Figure 4). However, the restored plot showed the longest interpatches (1.1 m vs 0.7 m in the Degraded) although differences were not significant. Interpatches in Odigitria were constituted by a mixture of grasses, stones and bare soil.

" data-placement="top" data-content=" Figure 4. Values of Interpatch length (left) and cover (right) in the Reference, Semi-Degraded, Degraded and the Odigitria Restored plot in Messara field site." title="">

" data-placement="top" data-content=" Figure 5. Values of patch length (left) andwidth (right) in the Reference, Semi-Degraded, Degraded and the Odigitria Restored plot in Messara field site. Different letters indicate significant differences." title="">

Patches in the restored plot averaged 1.61 m long and 0.95 m wide (Figure 5) and were mainly constituted by shrubs and subshrubs (24.5 and 22.5% of the total surface area, respectively). The Degraded plots showed smaller patches (0.77 m long and 0.71 m wide) with lower proportion of shrubs (18.0%) and slightly higher cover of subshrubs (27.9%, mainly the unpalatable species Urginea maritima). The Reference plots showed the highest diversity of patch types where shrubs were the most abundant (33.8%) followed by subshrubs (15.2%) and tussock grasses (10.0%).

LFA indexes in Odigitria restoration showed some differences to the restoration in Melidochori. Stability and infiltration did not change in relation to the Degraded plots while nutrient cycling was slightly improved (from 22.2 to 26.6%; Figure 6). The Reference released the highest values for both infiltration and nutrient cycling indexes while the stability was highest in the Semi-Degraded.

" data-placement="top" data-content=" Figure 6. Values of the Stability, Infiltration and Nutrient Cycling indexes derived from LFA in the Reference, Semi-Degraded, Degraded and the Odigitria Restored plot in Messara field site. Mean and standard errors are shown." title="">

" data-placement="top" data-content=" Figure 7. Losses or gains (negative and positive values, respectively) of assessed ecosystem properties in the Restoredplots of the Messara field site in relation to the Degraded areas. Asterisks denote significant differences between ecosystem states (*: 0.05<p<0.10; **: 0.01<p<0.05; ***: p<0.01)." title="">

In general, most of the ecosystem properties evaluated through the LFA assessment were improved with restoration, especially with the Odigitria approach (Figure 7). The perceived significant increase of interpatch cover and length cannot be seen as positive changes.

Note: For full references to papers quoted in this article see

» References

Messara, Greece: Stakeholder workshop to evaluate SLM guidelines and scenario analysis

2017-07-05T11:43:40+00:00

Main authors:	Cecilia De Ita, Lindsay C. Stringer, Luuk Fleskens, Diana Sietz
Contributing authors:	Ioannis K. Tsanis, Ioannis N. Daliakopoulos, Ioanna Panagea, Michalakis Christoforou, Giovanni Quaranta, Rosanna Salvia, Sandra Valente, Cristina Ribeiro, Cláudia Fernandes, Oscar González-Pelayo, Jan Jacob Keizer, Alejandro Valdecantos, V. Ramón Vallejo and Susana Bautista
Editor:	Jane Brandt
Source document:	De Ita, C. et al. (2017) Report on multi-scale evaluation of CASCADE's management principles and grazing model scenarios with stakeholders and policy makers. CASCADE Project Deliverable 8.3 69 pp

Based on previous experience, farmers are reluctant to attend stakeholder meetings involving management authorities and are more comfortable to be reached individually, therefore the farmer’s representative attended to speak for other shepherds/farmers. Hence, although over 20 stakeholders were invited, only 7 individuals attended (Figure 1). Despite this situation, CASCADE study site researchers considered that as the farmers’ representative is very well informed on current affairs due to his previous position as head of the pastoralists’ union of Heraklion, and long-term involvement of he and his family in the livestock farming profession, the shepherds’ views were adequately represented.

In the first part of the meeting, participants were shown the »»CASCADE movie clip in order to demonstrate that problems in drylands are common among CASCADE’s study sites. Stakeholders could especially relate to and comment about the overgrazing problems described in Cyprus. Afterwards, TUC researchers gave a short presentation on the CASCADE results for Crete regarding (a) stress gradient experiments, (b) drought stress experiments, (c) CASCADE grazing principles, and (d) cost-benefit scenarios. Stakeholders were urged to interrupt and discuss any points they wanted to raise during the presentation.

" data-placement="top" data-content=" Figure 1. Participants in CASCADE’s overgrazing workshop in Crete." title="">

Stakeholders’ perceptions of grazing principles in Crete

For descriptions of the principles discussed here, see »Guidelines for land managers: the overgrazing context_EN.

Every participant in the workshop agreed with criterion 1 "Keep a minimum of 30-40 % soil cover", and criterion 2 "rotate grazing areas and control the amount of animals" of principle 1 “Reduction of vegetation increases soil erosion, leading to less fertile soil and less productive pastures”. Criterion 1 was seen as feasible by all the participants. However, keeping animals in stables (criterion 3: use stall feeding, especially during the dry season), was considered feasible by non-pastoralists but unrealistic by pastoralists. This is due to current stable installations, as they are rudimentary, and stable construction costs are high.

Regarding principle 2: “Integrating trees and pastures has ecological and socio-economic benefits”, everyone considered protecting existing trees and planting fruit and fodder trees an effective measure. However, opinions were divided regarding how realistic it is for the stakeholders to apply this. Silvo-pastoralism and market diversification are already applied by a few more educated and open-minded farmers who took advantage of financial instruments to plant trees on their land or invest in agro-tourism. To some extent, land tenure was perceived as a barrier: small land owners may not be able to apply such instruments due to the high costs that this implies, and the lack of access to subsidies. Also, small producers are using their products only for subsistence.

Stakeholders agreed with the protection of wildlife and criteria in principles 3.1 and 3.2 “Protect ecosystem floral and faunal diversity, avoid killing predators”, and stated they already avoid killing predators such as snakes. Measure 3.3 “Protect trees against rats” was not relevant for the area.

Regarding 3.4 “Install fences and traps” and 3.5 “Provide nest boxes for birds of prey”, fencing was not considered realistic, due to the nature of the landscape, while trapping can only be managed at the administration level if such a need arises, otherwise it is illegal. Researchers mentioned that the use of nesting boxes could be appropriate, but administrators and farmers did not consider it necessary, as indigenous bird populations are not at risk.

Stakeholders agreed with principles 4.1 and 4.4: “Plan resting periods for pastures”, and “Increase health and productivity of individual animals instead of increasing the size of the herds” respectively. However, principle 4.4 was not considered feasible by any stakeholder. Regarding animal types and herd composition from principles 4.2 and 4.3 “Selectively remove unwanted species, while keeping some for soil protection if necessary” and “Diversify animal types”, stakeholders agreed with selectively removing unwanted species, while keeping some for soil protection if necessary. They also agreed with animal diversification, although extensive planning for rotational grazing was considered realistic by non-pastoralists but unrealistic by pastoralists. Animal diversification beyond sheep and goats was not considered feasible by any of the stakeholders. Stakeholders considered that including goats in the herd endangered forested areas, as their efficiency in grazing threaten the viability of the vegetation and limit regeneration. Furthermore, goats can also eat the bark of the trees, leaving them susceptible to diseases. Therefore, diversifying grazing including goats was perceived as a problem.

All stakeholders agreed with principle 5 “Controlled grazing reduces risk of fires” the most. This is because they saw that controlling grazing can reduce the risk of fires by reducing the fuel load. Installation of fire breaks and the reduction of bush cover in order to allow grazing and reduce fire risks are already being applied. However, they did not agree with reducing grazing during the dry season, and perceived that grazing should be increased when dry matter increases. Reducing grazing during the wet season makes more sense for stakeholders. Excluding grazing for at least 4 months during the wet season was suggested. This mimics the traditional transhumance pattern of moving to lower grounds during the winter season both for shelter and to allow vegetation to grow before it is grazed. They considered that grazing should be allowed during the dry season when biomass has grown otherwise it would only provide fuel for fires.

All stakeholders agreed with the effectiveness of the measures in principle 6 “Actions after a fire or drought”. Burned lands are typically included in a reforestation zone plan. Two years was considered the minimum resting period by farmers; 5-6 years was perceived as adequate.

Stakeholders’ perceptions of findings from the scenario analysis in Crete

Stakeholder discussions of findings from the scenario analysis in Crete can be summarised as follows. For degraded sites, participants considered that increasing vegetation cover requires extensive financial resources and the benefit is only environmental. Furthermore, small interventions make little difference. In this sense, the vegetation trends and financial benefits/losses described in the models were considered realistic. In non-degraded/restored sites there is high potential for sustainable management. Excluding grazing during the wet season can be profitable. In order to successfully apply this though, fodder needs to be provided.

The assumption made in management scenarios implying annual decisions on livestock destocking (keeping animals in a stable rather than selling them) or restocking (moving animals from stable to pasture rather than buying new animals) is problematic for degraded initial conditions. Currently stable installations are rudimentary at best and therefore the cost of destocking should include stable construction. Even the traditional model of transhumance (moving animals to higher ground in the summer and lower grounds in the winter) is currently unfeasible due to labour costs and land fragmentation. Therefore, stakeholders consider that partial animal exclusion in traditional/degraded lands is largely unrealistic. Partial exclusion was however considered realistic in non-degraded or restored lands when lower animal densities are also assumed. Total exclusion is considered unrealistic in all cases.

Contrary to the reactions towards the results of the grazing model, the stakeholders showed some disagreement with the grazing guidelines and recommendations of the grazing principles. As mentioned before, they did not agree with reducing grazing during the dry season. On the contrary, stakeholders considered that grazing should be increased when fresh matter decreases and dry matter increases as vegetation dries out. They felt that reducing grazing during the wet season makes more sense, also in accordance with the “resting in wet season” scenario. Excluding grazing for at least 4 months (wet season) was considered appropriate.

In responding to question 3 (in sites where vegetation was successfully restored, how severely was the vegetation degraded (% cover) when restoration started?), stakeholders could not answer using a simple percentage. This is because the perception of degradation as a function of vegetation cover was not considered entirely realistic. Some participants noted that some sites have been successfully restored after having 0% vegetation cover. Several such examples were discussed and these observations also agree with findings from the CASCADE stress gradient experiments (see »Simulated pressures and ecosystem responses). According to the stress gradient results, degraded sites may be more fertile, with higher amounts of soil organic carbon (SOC) and N, probably as a result of the higher amounts of manure left during grazing. The limiting factor in these cases is soil depth which gradually erodes when vegetation cover is low. Vegetation cover is in some cases a good proxy for degradation but does not depict the permanent loss of other land resources such as soil.

How many animals per hectare were grazed prior to degradation on these sites (=cause of degradation)?

The perception of the number of animals considered as overgrazing varied, and stakeholders were reluctant to set a clear threshold for overgrazing. In their view it is a complex situation that depends on grazing strategies (constant or rotational grazing). E.C. Reg. 1782/2003 suggests livestock density has to be maintained at 1.4 head/ha (Hadjigeorgiou, 2011). The limit for Natura 2000 is 0.2 to 3 LU/ha. Stricter regulations for single areas are possible (Dimopoulos et al., 2006) and indeed necessary (Papanastasis et al., 2002). Current average density is 1-1.4 head/ha. Nevertheless, as much as 4-8 heads/ha can be considered sustainable if rotational grazing is applied. If rotational grazing is not applied over 2 heads/ha may be considered overgrazing.

Note: For full references to papers quoted in this article see

» References