Keywords

1 Introduction

Extensive soil and land degradation processes leading to desertification affect Greece. Many observed degradational processes are directly or indirectly induced by humans and accelerate climatic change and extreme climatic events, which may further exacerbate the impacts of land degradation. The aim of this chapter is to present the status of land degradation in Greece, to describe the natural processes in the different components of land, and the human activities that have direct or indirect impacts on resource degradation. Also, to highlight land conservation measures applied or needed to be applied to combat desertification and to propose extra measures and the necessary framework, which policy makers should develop and apply in order to reduce, stop or even reverse negative trends.

The total area of Greece, according to the last census (2001) is 13,195,740 ha, 30% of which, is cultivated land, 40% is pasture land, 22% forest land and the remaining 8% is water, buildings etc. Threats and degradation processes to soil and land as well as land protection policies and actions have been also presented previously by Theocharopoulos and Aggelides (1991), Davidson and Theocharopoulos (1992), Lyrintzis and Papanastasis (1995), Yassoglou (1987, 1999, 2005) Theocharopoulos and Panoras (2000) and Theocharopoulos (2007).

2 Land Degradation and Desertification Status

The United Nations Convention to Combat Desertification (UNCCD) defines “land” as “the terrestrial bio-productive system that comprises soil, vegetation, other biota, and the ecological and hydrological processes that operate within the system”, while land degradation is defined as “the temporary or permanent lowering of the productive capacity of land”. The same convention defines desertification as “land degradation in arid, semi-arid and dry sub-humid areas resulting from various factors, including climatic variations and human activities”.

Land is a resource and also a complex living system. The rate of soil and land degradation processes as well as the land use and management practices, which operate in any point or ecosystem in Greece could be described by soil and land quality indicators, and supported by a proper monitoring system. A temporary or permanent lowering of the productive capacity of land is recognized throughout the country, but varies from place to place. Potential desertification and land degradation risks result from various factors, including climatic variations and human activities as presented in Fig. 33.1 prepared by the Greek National Committee to Combat Desertification (Yassoglou, 1999). Land degradation intensities are due to natural processes such as landforms shape and pattern, climate, extreme climatic events, but the human induced processes are those that in most cases accelerate the process. The final consequences are reflected by the inefficiency of the land to maintain its economic and ecological functions and an irreversible reduction capacity to produce goods and services. Based on soil, climatic and topographic characteristics land of potentially high quality covers 19%, land of moderate quality covers 18%, while the rest of the land (57%) is of low quality (CORINE, 1992).

Fig. 33.1
figure 1

Potential desertification map of Greece (Courtesy Prof. N.J. Yassoglou et al., 1999)

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The main human induced degradation processes in the country could be recorded as accelerated soil erosion, soil disturbance, removal of vegetative soil cover and/or hedgerows, abandonment of terraces, overstocking and overgrazing, poor and inappropriate crop management like burning of crop residues, wild fires etc.

2.1 Soil Degradation

Soil degradation is only one aspect of land degradation that describes the physical, chemical and biological degradation of the soil through the reduction in its ability to fulfil its functions related to productivity and the environment. Soil degradation process in Greece, is described by Theocharopoulos (2007), Kosmas et al. (2006), Yassoglou (1999), and others. The soils of Greece developed on the characteristic steep Mediterranean landscapes (Theocharopoulos, 2007) are mostly shallow without well-expressed pedomorphological horizons (Leptosols, Regosols), which mainly suffer from soil erosion, organic matter decline and nutrient depletion. The deep soils in the lower lying plains and the soils near the coast, where water is stagnant, or sea water intrusion occurs due to over pumping, are degraded by salinization and/or sodification. To this also contribute streams and groundwater, which contain significant amounts of wind-borne salt or salts from parent materials.

Water and wind erosion, loss of organic matter, salinisation, alkalisation, compaction, fertility depletion, crusting, decline of biodiversity, acidification, leaching, soil pollution and contamination, and sealing, seems to be the main degradation factors or processes occurring in Greece. The severity of each factor varies spatially and temporarily but no detailed information is available at present.

Soil erosion is the natural process of removal of soil by water or wind. Over millions of years, the deposition of these materials has built up fertile plains. Soil erosion is accelerated by inappropriate land management, by land use changes such as clearance of forest and grasslands followed by cropping that provides inadequate ground cover, inappropriate tillage, overgrazing, mining and earth moving, and poor maintenance of conservation measures such as terraces. Loss of topsoil means reduction of fertility, organic matter and losses of nutrients, reduction of water holding capacity, and decline of biodiversity, all of which create irreversible changes and reduce on-site soil quality. The eroded soil is usually deposited in downslope areas or could reach the seas. The off-site costs include damage to infrastructure and sedimentation of reservoirs, streams and estuaries, and losses of hydropower generation, that might in some cases be much greater than in situ losses of farm production. Widespread attempts to mitigate soil erosion in Greece during the past century have produced mixed results.

Measurements conducted in western Greece where flysh formations are dominant, and in a number of sites in eastern part of the country indicate that the sediment load transported to dams ranges between 1,200 and 2,000 t km2 year–1 (Kosmas et al., 2006). Danalatos (1993) describes complete removal of the thick dark surface of soil horizon in the hilly Tertiary landscapes of central Greece at rates 1 cm year–1, while Kosmas et al. (2006) mention erosion rates of 0–52 t km2 year–1 in Viotia area, and from 15 to 252 t km1 year–1 in vineyards in Attica. Using 137Cs technique Theocharopoulos et al. (2003) estimated erosion rates in Mouriki catchment and Viotia area in the range of 3.54–95.78 t ha–1year–1, while the deposition rates ranged from 1.23 to 168.19 t ha1year–1. It is estimated that 8% of the hilly agricultural land in Greece has been abandoned in the last decades due to diminished productivity caused by soil erosion (Kosmas et al., 2006). According to Danalatos (1993) analytical data in Thessaly have shown a reduction of soil organic matter, from 2.6 to 1.5% only during the last 6 decades.

Erosion by wind also occurs when the wind force is greater enough to detach bare soil structural units as mainly in the Aegean islands and Crete and carry soil particles away. This depends on wind speed, surface roughness, vegetative cover, soil moisture and erodibility, which are often aggravated by changes of land use, cropping and grazing regimes.

Wild fires in forests and bushes, plant cover removal or overgrazing, climatic change, rainfall pattern and intensity, soil structure deterioration, top soil treatment, current land use, soil cultivation patterns and stable burning are the main factors accelerating erosion, decreasing soil organic matter, and accelerating nutrients leaching (Blake et al., 2009; Theocharopoulos et al., 2003, 2004) with all other consequences to soil structure, erosion, fertility etc.

Agriculture intensification has led to increased and sometimes excessive application and leaching of fertilizers (Theocharopoulos et al., 1993). The use of excessive amounts of manure, sewage sludge and pesticides (Papadopoulou-Mourkidou, 1998; Lolas, 1998), has introduced soil pollution, contamination and decline of biodiversity. Haidouti et al. (1985) reports the presence of mercury in some Greek soils. Industrial development in Greece seems to have brought about, directly or indirectly large additions of wastes and pollutants, including heavy metals and acid rain.

The use of more powerful heavy machinery has led to compaction and loss of structure, and has, despite the crop production problems, indirectly accelerated soil erosion. Acidification, with the consequent plant toxicity, occurs because of soil carbonates leaching or improper use of acidifying fertilizers or industrial emissions. The need for housing, industry, infrastructure etc especially around big cities and near the coast has given rise to the removal or loss of high quality land from its natural function through its allocation for other uses.

The 2006 report on coastal zone management of Greece mention that 28.6% of the coastline is affected by erosion, while the total urbanised coastal area is estimated to be 1.31% of the total surface are. If this be combined with the fact that 70% of the coastline is rocky it is highlighted the increased degree of urbanisation in the coastal area.

2.2 Water Degradation, Scarcity and Quality Deterioration

Soil and water resources are in close contact in nature and interact between them. This is the reason these should treated together. Pollutants through water diffusion, mass or bypass flow either in solution or suspension reach the soil, surface and ground water. Also, soil processes like soil erosion, leaching, macropore flow, and mineralisation of humus affect water quality.

Surface water in Greece consists of rivers, lakes, and wetlands. In the northern part of the country there are the rivers Ebros, Nestos, Strimon and Axios with most of their catchment inside Greece. While other important rivers are Aliakmon, Aheloos, and Pinios. Natural lakes are small apart from Prespes only part of which belongs to Greece. Groundwater aquifers throughout the nation are either carbonate rocks (karstic aqifers) or coarse-grained Neogene and Quaternary (porous aquifers) deposits.

The hydrologic regime corresponds to conditions characterized by the inadequate availability of water resources and the Mediterranean hydroclimatic conditions. In Eastern regions of the country, the islands of Aegean and Crete face a critical endemic shortage of water. This is enhanced by high agriculture water consumption especially by summer crops. Many areas in Greece do not satisfactorily cover their water demands and experience problems in water supply.

The main users of water resources are agriculture (85%), followed by urban uses and industry. Irrigated land (Theocharopoulos and Panoras, 2000) is estimated to be 1,250,000 ha; 600,000 ha of which are irrigated from surface water, while the rest 650,000 ha from pumped ground water. The spatial and temporal distribution of water demand is irregular while maximum demand is recorded during July and August and in the main plains or near the coast. Water management in agriculture is not rational and needs improvement especially to reduce water loss that start from the reservoirs to the field. Demands for potable use present also a spatial and temporal distribution due to tourism. The use of ground water resources has become particularly intensive in coastal areas due to intense urbanization, tourist development and irrigated land expansion (Daskalaki and Voudouris, 2007).

Lolas (1998) reports pollution from agrochemicals while Albanis (1992) reports herbicide losses through runoff from the agricultural land of Thessaloniki. Papadopoulou-Mourkidou (1998) reports that nitrates as well as atrazine, metalachlor and alachlor were detected in 78 out of 142 ground water samples in Northern Greece. Pesticide residues were also detected in Loudia River (Papadopoulou-Mourkidou, 1998). Mitsios et al. (2000a,b) detected heavy metals in soils and irrigation water in Thesaly as well as Borium in soils and irrigation water but not in high levels. Vizantinopoulos and Lolos (1994) studied the leaching and persistence of pesticides, while Lentza-Rizoy (1996) detected triazine in two areas. Miliadis and Aplada-Sarli (1995) report pesticides residues in surface and ground waters with seasonal fluctuation. Additional sources of water pollution come from the seawater intrusion due to over exploitation of coastal aquifers, the fertilizers used in agriculture and the disposal of non properly treated urban and industrial wastewater in torrents or in old pumping wells.

Overpumping from ground water is used to irrigate summer crops and satisfy tourism needs. This has created lowering of the ground water level while such form of water is most of the times of poor quality and enhances salinisation. Seawater intrusion is enhanced because the ground water level has lowered very much below the sea level in many places. Addition of nutrients through soil erosion, runoff and leaching could create eutrofication in many water reservoirs.

According to Xanthakis et al. (2009), from a total of 236 ground aquifers in Greece, 110 of them are threatened from degradation and pollution such as not to fulfil the qualitative and quantitative requirements of the 2000/60 EC guideline.

The major risks of surface and ground water uses in Greece could be summarised as follows:

  1. 1.

    Pollution from industrial and urban areas

  2. 2.

    Point pollution from non properly treated municipal and industrial wastes

  3. 3.

    Pollution from agrochemicals and fertilizers

  4. 4.

    Poor water use efficiency and high losses of water

  5. 5.

    Overexploitation and intensified drainage leading to lowering of ground water levels

  6. 6.

    Seawater intrusion in many coastal areas

The increased needs for water quantity and the protection of water quality necessitates optimum use of water resources, protection of water quality, and sustainable irrigation management systems. This could be achieved by using limited irrigation water supplies based on crop water requirements and optimum irrigation scheduling. The situation is becoming even worse under the systematic climate change. Improvement of soil infiltration, injection of water to ground and water recycling could be some adaptation remediation measures to face these problems.

Great efforts to save water are taking place in the country. In this context, water is being recycled (Panoras et al., 2000), and pressure is growing to allow transfer of agricultural water supplies to other uses. The EU directive 2087/92 is applied in order to minimize the detrimental effect of water misuse and pollution to the environment. The Ramsar agreement is also activated for the protection of wetlands. Despite the European Water Framework directive 2000/60 which has established a new legislation for sustainable management of water resources and protection of their relevant ecosystems, it seems that there is an urgent need for establishing the best institutional and policy practice for water management, along with the creation of a lasting network of institutional research policy for enhancing the productivity of water at national and local level (Mimikou, 2005).

2.3 Decline of Biodiversity

The biodiversity in the form of the variety of plants and animals in the protected areas of the country are well described in Earthtrends country report for Greece. As all other Mediterranean countries, Greece too is strongly affected by unsustainable development reflected by the loss of valuable forests, agricultural, coastal and marine ecosystems that were destroyed to accommodate recreational activities at sites that were important habitats for fauna and flora. It seems that wildfires, which occur almost every summer in Greece, cause the most severe damage to the ecosystems.

In addition to wildfires, monoculture, increased use of agrochemical in agriculture, unsustainable land, forest, soil and water management, have induced soil, water and air pollution and reduced biodiversity provoking changes in the population dynamics of flora and fauna and destroy the ecological balance of the natural ecosystems. According to Article 17 Report of the National Summary for Greece the frequency of pressures and threats in agriculture and forestry are 60 and 40% for natural habitat threats.

Frequent wildfires cause changes in the forest and the other ecosystems, and affect fauna and flora population dynamics as well as soils and downstream waters (Blake et al., 2009). Forest ecosystems play a crucial role in increasing water infiltration, preventing soil erosion and runoff, maintaining soil fertility, hosting most terrestrial biodiversity, and help sequester carbon in the soil thus should be protected. To face the problems of biodiversity decline especially after forest fires there are numerous areas in Greece that need urgent reforestation programmes as proposed by Trakolis et al. (2000) for the Voras Mountain. Biodiversity research is foreseen in two out of eleven national thematic priorities of the Strategic Development Plan for Research, Technology and Innovation under the 2007–2013 NSR Framework and the Greek National Biodiversity Strategy that match the EC communication on “Halting the loss of biodiversity by 2010 and beyond”.

2.4 Land Use Change

The main human induced contributing factor to land degradation in Greece is land use change as it is shown in Table 33.1.

Table 33.1 Changes in the main land use categories in Greece for the period 1971–2001 (in 000  ha)
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These changes, that in many areas are historical, have immediate consequences on food production, soil and freshwater resources, forest resources, biodiversity, climate and air quality. On the other side fertile soils were lost to host urban and industrial development. Fires and urbanization of the population of the rural areas are some other reasons of land use change. The use of genetically modified organisms and crops for food production has not been fully investigated and they are at the moment, contested scientifically and politically in the country. Land use change surely will be introduced to face climatic change through new crops that are tolerant to drought conditions, sown later in winter or early in summer in addition to crop redistribution to face the raising temperatures. To avoid further degradation this has to be based on land capability and land suitability principles and requirements. In this context Xanthakis et al. (2009) estimated that if 75% of the Greek land cropped by cotton was shifted to winter wheat, then the irrigation water consumption decrease would be enough to cover the potable water needs for the whole population of Greece.

3 Actions to Mitigate Land Degradation

The national strategy for soil and water resources considering land use planning and climate change was presented, described and discussed in a Conference organized by the Ministry of Rural Development and Food (MRDF) in Athens, 25th February 2000 and presented by Missopolinos et al. (2000). The outcomes of this event have established the main priorities for sustainable land management as follows:

Improvement and broadening of scientific and technical knowledge on soil functions, scientific knowledge dissemination, selection of best soil uses in relation to soil functions, development of the proper tools to monitor, protect and improve soil quality, development of soil quality monitoring systems, improvement of the deteriorated soil functions, mapping and evaluating soil resources, monitoring and management, research, and enacting proper legislation.

Research projects to combat land degradation are carried out by the Soil Science and Forestry Institute of NAGREF and by relative units of many Greek Universities. All stakeholders, especially policy makers, should be informed and aware of the problems of land degradation and desertification.

Effective mitigation of land degradation and desertification should start from the prevention and establishment of early warning systems. The National Committee to Combat Desertification has produced the National Action Plan (Yassoglou, 1999) where all the factors and processes leading to land degradation and desertification are described in detail. Also, the general and specific measures and actions for agricultural practices, forest and pasture management and protection of biodiversity are presented along with the necessary socio-economic measures. A number of actions such as conservation agriculture with its three pillars of no till, mulching, and proper rotation as well as conservation tillage seems to be a good approach, to protect the soil and to maintain soil fertility.

The Greek Ministry of Rural Development and Food has also produced the Code of Good Agricultural Practice (CGAP). The “Greek Action Plan” for the mitigation of nitrates in water resources of vulnerable districts such as Thessaly, Kopais (Kallergis, 1997), is also implemented. It comprises a set of measures and practices targeting the protection of surface and groundwater aquifers from nitrate pollution of agricultural origin, through the rational management of inorganic fertilizers. On the other special attention is due to the use of sewage sludge is in accordance with EU Council Directive 86/278. Land protection is being implemented in the Framework of Reg (EU) 1257/99, which incorporates protection of the environment in the rural development areas. The 2000/60/EC Water Protection Directive has been into practice as well and will certainly contribute towards reversing land degradation trends.

Subsidies are offered to farmers who comply with good agricultural practices that are friendly to the environment. They include reduced nitrogen inputs, anti-erosion measures such as ploughing across slope, build or preserve terraces, extensification of animal husbandry, organic farming or organic husbandry, long time set aside land, protection of sloping landscapes etc. Through the integrated crop management systems, productive soils are protected from agrochemical residues and through water protection measures to conserve various lake ecosystems throughout the country.

The EU, through its new Common Agricultural Policy (CAP) and its Soil Thematic Strategy incorporates environmental issues in rural development and will contribute towards stopping and mitigating land degradation. A harmonized Land Degradation Monitoring System has to be established in Greece, based on new technologies with minimum sets of parameters/indicators, with quality control/assurance procedures for soil, water and biodiversity sampling, treatment and analysis and with traceability rules to be followed. Harmonized Guidelines for sustainable land use should be formulated too.

4 Conclusions

Land degradation is a serious problem in Greece. It needs proper actions and measures, education and public awareness. The country should consider the current threats and should update and implement its National Action Plan to combat desertification and land degradation. Harmonized guidelines for the sustainable use of land and protection of soil, water and the biodiversity should be formulated. A harmonized monitoring system for land degradation, based on remote sensing and expert based assessments with a minimum set of land quality indicators, needs to be developed. Finally, necessary legislation should be developed, approved and implemented.