Drivers of LEDD in cropland: Western Andévalo

Editor's note 30 Apr 2012: Text source D111 section 3.2

Changing agricultural practices

In terms of natural capital, the main drivers of LEDD in cropland in semi arid areas such as Western Andévalo are related to water and soil (organic matter). These drivers also impact on social and economic capitals. As in many other regions, in order for agricultural products from the Western Andevalo to compete in global markets, modern agricultural practices are designed to meet the needs of specific crops. The Andévalo region is currently in the process of being reformed into orange plantations on a scale of importance on a national and international level. Chemical fertilizers and pesticides are therefore being used, for example, to assure crop yields. The majority of these practices are not sustainable and problems associated with LEDD therefore arise. Soils become depleted and depended on mineral fertilizers. With increasing mechanisation, fewer workers are needed in agricultural areas and where demand for labour remains, such employment is often seasonal and short term - for example the use of migrant and temporary workers for harvesting oranges.

Mining activity

The Iberian Pyrite Belt, which touches the north of the Baixo Guadiana area, is one of the most important volcanogenic massive sulphide ore deposits in the world (Delgado et al. 2010). Mining activity in this area historically stems from the Bronze Age (Davis et al. 1999). Many mines closed during the mining crisis in the 20th century but as a result of changing global markets, some mines are reopening. Mining activity in the past has lead to environmental pollution from acid mine drainage and heavy metal soil contamination in the Guadiana Basin and Huelva province (Andalucia Innova 2009, Delgado et al. 2009).

Industrial activity

Huelva, the capital city of the province, is one of the oldest industrial cities of Spain. A recent study by Fernández-Caliani (2011) showed that in the peri-urban area, soils are heavily polluted as a result of industrial chemical production activities and poor management of industrial wastes. Samples showed that sites should be regarded as contaminated soils for which risk reduction measures should be taken. The agricultural products from these per-urban areas are at risk of contamination as a result of these polluted soils.

The production of phosphate fertilizers for agricultural use is concentrated on an industrial site in the city of Huelva. This complex is situated in an estuarine zone of salt marshes, with high ecological sensitivity and value. One of the by-products of the production process is phosphogypsum. This product has high contents of potentially toxic metals and radioactive elements. More than 3 Mt of phosphogypsum waste is produced each year and deposited in stacks one kilometre from the city centre (Pérez-López et al 2007). This dump contains about 100Mt of phosphogypsum and until 1998, 20 percent of the waste produced was poured directly into the Odiel river. This has caused environmental deterioration in the area. Pérez-López et al (2007) found that the phosphogypsum in Huelva is particularly hazardous due to its higher concentrations of impurities. The waste dumps are vulnerable to leaching and weathering through which effluents contaminate water and soils with radioactivity and toxic metals (Periáñez et al. 1996).

Irrigated agriculture

In recent decades there has been a significant increase in irrigated farming in the region. In Andalusia, agricultural use accounts for almost 80 percent of all water use. Urban water use accounts for around 12 percent and use by industry accounts for approximately eight percent (Consejería de Medio Ambiente, Junta de Andalucía 2002). The water used in agriculture is for irrigation and is supplied mainly from superficially held resources such as small reservoirs. Coastal crops are supplied with ground water, which results in contamination of aquifers by marine intrusion caused by overexploitation. In Andalucía, tourism demand accounts for much of the urban water use, with a consumption rate that reaches its peak in the summer months, coinciding with peak agricultural water demand (Velazquez 2006).

Rural migration

Rural migration is an issue in Western Andévalo and Andalucía. The size of the population in rural villages is decreasing but at the same time the average age is increasing. These population changes are mainly caused by young people moving away for economic reasons, to places where employment opportunities are better, such as at the coast and in cities.  This process leads to an increase in the population of coastal areas, driven in part by increasing tourism. In the rural areas of Western Andévalo, this leads to fewer people working in the agricultural sector, resulting in land abandonment.

Land abandonment

A particular issue associated with land abandonment in Western Andevalo is the associated increase in fire risk. In contrast, one positive aspect of land abandonment in the region is the increase in soil organic matter and biodiversity as a result of the cessation of unsustainable land management practices.

Climate change

The Western Andévalo represents a typical semi-arid region, where human activity and modification of the hydrological regime over previous decades have led to increasing water scarcity and the identification of water shortage as a ‘structural characteristic’ of the system. Future climate change will act to amplify existing water stress, with important consequences for the availability and distribution of water between different uses of land (ADAM 2009).

Water stress is related to irregular rainfall patterns that are predicted to worsen on the Iberian Peninsula due to changing climate scenarios. According to meteorological records in the study area, a trend of declining precipitation can be observed between 1932 and 1996. Two trends in precipitation were recorded in Portugal and Spain during the MEDALUS Project (Corte Real 1996). These were the later onset of the autumn rainy period; and a decline in the reliability of rainfall in early spring and in particular in April. These changes have led to a reduction in winter percolation to groundwater and a decrease in the discharge of springs, affecting water availability in the flood plains. Water stress related to irregular rainfall, or the total absence of water during long dry spells, and salinity related to over-exploitation of springs are common impacts of changing weather patterns and increased anthropogenic water demand (Tadeo 2001-2006).  The expected climatic changes for this area are likely to change rainfall patterns; total rainfall is likely to be less than current but is expected to fall in more intense bursts during severe storms (Goodess and Jones 2002). These intense rainfall events are also expected to exacerbate erosion problems.

Urbanisation

It has been estimated that Spain has built more housing units than France, Britain and Germany combined during the last decade.  The amount of new housing reached 687,523 units in 2010. If the renovation of existing houses is also taken into account, the number of housing units totalled 1.1 million. In the western Andevalo area, the growth of urban areas is one of the main land use change issues. Close to the coast and near the town of Ayamonte, a new urban area named ‘Costa Esuri’ has been built, which occupies some 950 ha. Approximately 6,000 apartments have been built, along with two golf courses. This will significantly increase pressure on limited water resources. Moreover, approximately 600 ha of the total area has been constructed in a NATURA 2000 protected area.

Trans-border drivers

Although the Western Andévalo is part of Spain, the drivers related to LEDD issues are not confined to Spanish land use and rural development. The Western Andévalo is part of the Guadiana River basin, which is an international basin and forms the border between Portugal and Spain. Unilateral management decisions and policies concerning this drainage basin clearly have an effect on both countries. The scientific monitoring and management approaches used in this area are substantially different between Spain and Portugal. Water consumption issues have led to the establishment of discussions between Spain and Portugal on the water flow regime in the Guadiana basin. The consumption from the Alqueva (Portugal), Chança and Andévalo (Spain) reservoirs will eventually lead to a decrease of freshwater input to the Guadiana River. The expected increase in erosion and deterioration that accompany this decrease in water flow can be seen as an off-site impact in relation to the newly expanding water consuming agricultural practices in the Western Andévalo.

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