Agricultural terrace abandonment in the alpujarra, andalucia, spain

LAND DEGRADATION & REHABILITATION, VOL 5, 281-291 (1994)

AGRICULTURAL TERRACE ABANDONMENT IN THE ALPUJARRA, ANDALUCIA, SPAIN

T. D. DOUGLAS, S. J. KIRKBY, R. W. CRITCHLEY AND G. J. PARK Division of Geography and Environmental Management, University of Northumbria, Lipman Building, Sandyford Road,

Newcastle upon Tyne NEI SST, UK

ABSTRACT The environmental impact of recent changes in land use is assessed in a part of Andalucia, southern Spain, where the deintensification and abandonment of low productivity upland areas is taking place. In the uplands of the Alpujarra, the traditional landscape most at risk is that of the irrigated cultivation terraces. These have often been established centuries ago and rely on water abstracted from streams draining the southern slopes of the Sierra Nevada. The causes of this deintensification include labour shortages, with many Alpujarra reporting population decreases of up to 50 per cent since 1950. Landsat Thematic Mapper digital data from May and August 1992 have been used to identify the various land cover components of the Alpujarra. Ground verification undertaken in September 1992 and April 1993 has confirmed that deintensification of terraced areas around the villages of TrevClez (at 1500m, the highest village in Spain) and Portugos (1300m) can be identified as either grassland or -1. It is recognized that many classes of land cover are mosaics with several elements at a subpixel scale (e.g. terrace risers with fruit trees). However, the output from image processing has allowed areal estimates of the main land covers representing deintensification within the terraced zone. The pattern of deintensification of terraced land is fairly complex. It can be assumed that all terraces were irrigated and cropped at some stage. Land which is no longer cropped is usually grazed and the invasion of -1 species is common, particularly when irrigation ceases. Unirrigated tree crops and vines are sometimes planted on terraces no longer used for cropping. A model of deintensification of farming on terraced land in the Alpujarra is presented.

KEY WORDS Terrace abandonment Deintensification Alpujarra Southern Spain Landsat Thematic Mapper Classification Irrigated mosaic Agricultural terraces

INTRODUCTION

The environmental impact of recent changes in land use in parts of Andalucia, southern Spain has been studied. The intensification of potentially high productivity areas using high technology farming methods (e.g. greenhouse horticulture on the Campo de Dalias, Almeria) and the deintensification and abandonment of low productivity upland areas are taking place in close spatial proximity. Recent population data indicate a continuing exodus from the upland areas and often show reduced employment in the agricultural sector. As a consequence of these social and economic changes, new landscapes are being produced and new threats to environmental stability are appearing. This case study, part of a wider programme, looks at the pattern of deintensification of land use in a traditional upland landscape, part of the Alpujarra, a region between the Sierra Nevada mountains and the Mediterranean (see Figure l), and assesses the potential of Landsat Thematic Mapper (TM) data for identifying land cover components.

LAND COVER

The study area is located o n the southerly slopes and valleys draining from the Sierra Nevada (Figure l), Spain’s highest mountain range, which culminates in MulhacCn (3481 m). The study area lies in the internal zone of the Betic Cordillera and the Sierra Nevada corresponds to a major tectonic unit, the Nevado-Filabride Complex. The dominant lithology of this complex is mica schist. Plate 1 is a false

CCC 0898-5812/94/040281-11 @ 1994 by John Wiley & Sons, Ltd.

Received 29 March 1994 Revised 5 May 1994

282 T. D. DOUGLAS E T A L .

/ I '. , .

Figure 1. Location map of the Alpujarra study area within Andalucia. The box shows the extent of the satellite image of Plate 1

colour composite of TM bands 4, 5 and 3 and is useful in discriminating visually between the major land covers. The summit ridge is characterized by rock and montane scree (dark blue on the image), snow- covered for at least three winter months and, above about 2800m, is within the crioromediterranean bioclimatic zone (Molero Mesa, et al. , 1992). Below this in the oromediterranean zone (ca. 2800-1900m), vegetation cover increases to give a low rn- of spiny shrubs, locally called (blue grey on the image). Below this, m a is common and usually dominated by larger shrubby species (green and blue green on the image) and with varying proportions of bare rock/soil and a few areas of the climax vegetation, open pine woodland (Pinus sylvestris). Upland grasslands are encountered locally on cirque floors and gentler slopes (yellow on the image). Afforestation, mainly pine, (Pinus nigru and P. syfwestris) is fairly extensive between 1800 and 2500m (dark red on the image). Lower down, in the supramediterranean zone (between 1500 and 1800m), can be found remnants of previously more extensive oak forests, composed of evergreen Mediterranean oaks (Quercus ilex and Q. cocciferu) mixed with deciduous oaks (e.g. Q. pubescens) and other broadleaf trees such as chestnut (Custuneu sativu) (various shades of brown on the image). Finally, fed by the irrigation waters from streams draining the snows of the Sierra Nevada, are the terraced agricultural slopes. This area is a mosaic of polyculture with small terraced fields clustered around the hill villages. The irrigated mosaic is clearly demarcated by bright orange tones and the villages themselves appear blue/purple. Within the TrevClez valley, the terraces are common from 850 to 1800m and then occur sporadically to as high as 2300m.

TERRACED AGRICULTURAL SYSTEM

Agricultural terraces are one of the most distinctive components of the landscape of the Alpujarra. They are the key production units in a traditional land use system in which villages use different altitudinal

TERRACE ABANDONMENT IN THE ALPUJARRA 283

zones of the Sierra Nevada and Alpujarra for complementary products: the high slopes for pasture and the lower slopes for woodland. This woodland, is still used for commercial and construction timber, fuelwood, charcoal, hunting, honey production and for the collection of edible chestnuts.

The present system of terraces was constructed and maintained over a period of five hundred years to facilitate water and soil management on the steep hillslopes and to allow the intensive production of a wide range of field, bush and tree crops. Water is extracted from the b- (ravines) and streams which drain the snowfields of the Sierra Nevada, through a complex series of a& (water leets) to individual fields. Terraces and associated water control systems have been essential in the sustainability of the traditional land use system of the Alpujarra for more than a thousand years (the present structures were, in fact, a redevelopment of the sophisticated management methods used by the Moors in this area from about AD 800 until their expulsion in the 1570s). If the terraces and the associated water control structures had not been developed, crop yields would be considerably lower and soil erosion rates much higher. McNeill (1992) identifies four periods during which terraces were abandoned: firstly, when the Moors were expelled from the Alpujarra after 1571; secondly, when mining was developed in the 18th century; thirdly, with deforestation and extension of agriculture in the mid-19th century; and fourthly, during the last 40 years with the deintensification and abandonment of farming on the terraces. Each of these periods of terrace abandonment is believed to have been accompanied by an increase in soil erosion and a crisis of production. There is some uncertainty about the present rates of erosion in the Alpujarra. Thornes (1976) gives figures of between 370 and 575 t kmP2 y-l for Mecina Bombaron, Ugijar and Berja in the central Alpujarra, but Quirantes Puertas (1987) cites 2000 t km-2 y-’ for the high Alpujarra. Gullies near TrevelCz, by analogy with similar features elsewhere in Spain [for example Lopez Bermudez (1990), discussing the Segura Basin] may yield the equivalent of more than 20000 t km-2 y-’ for very small areas.

Almost all of the cropped land in the Alpujarra is irrigated: land that is not irrigated will give such low yields as to be scarcely worth sowing with field crops. The construction of irrigation systems, water tanks and terraces, the removal of stones and the improvement of soil structure and fertility through manuring are expensive in time and labour, and undertaken only as long term ‘landesque capital’ investments (Editors note: investment in enhancement of land utility). Some of the higher terraces, developed during the mid-19th century at a time of severe land shortage and on marginal land, were less carefully constructed. Even here, however, terraces were intended to be used for many years, if the labour investment were to be justified. Irrigation conveys a double advantage: firstly, yields are signifi- cantly higher than on rain-fed land and, secondly, even in drought years the probability of a complete crop failure is much less. Terracing of land increases the benefit of irrigation by allowing the creation of a thicker and more stable soil and by extending the area that can be serviced by irrigation.

After the terrace system has been constructed, the labour needed for maintenance is less. Farmers are therefore likely to continue to use their improved land for cropping even when farming becomes difficult through labour shortage or other problems. If, however, the irrigation system falls into disuse, the other landesque capital investments are immediately devalued. Even so, the unirrigated terraced land has a residual value as the soil has been improved, the grazing quality of the land is higher than that of unimproved land and tree crops will fare better on the improved land. Climatically marginal terraced land, particularly those areas taken into cultivation at times of extreme land hunger, usually at high elevations, will support lower yields for comparable inputs and are therefore likely to be the first to be abandoned. This is particularly clear in the upper TrevClez valley, where land that was used for crops in the 1920s (Brenan, 1957) is now used only for grazing cattle during summer.

AGRICULTURE BEFORE 1950

Over a period of several hundred years, Moorish settlers developed a carefully managed system of terraced irrigated agriculture, particularly at lower elevations in the Alpujarra. This system collapsed with the Reconquista (reconquest) in the late 15th century and was replaced by environmentally damaging m c farming (farming without irrigation and without terraces). By the mid-19th century,


1600

1400

1200

600

Year

- Trevelez -- Portugos

Figure 2. Population of the EEi&ks of P6rtugos and Trevilez between 1860 and 1986

however, the population had recovered to pre-Reconquista levels, depending again on irrigation and terracing. The introduction of maize and potatoes had allowed farming at even higher elevations, but this was a period of extreme land hunger and up to the 1950s almost every usable piece of land was under agriculture. In 1910 barley and rye were being grown at 2850m and potatoes at up to 3000m. The maximum population was reached in 1950 in almost every village in this part of the Alpujarra: at this time McNeill (1992) believes that communities were still largely self-sufficient and that the economy was still in effect that of the mid-18th century (see Figure 2).

AGRICULTURE SINCE 1950

The population started to decrease during the 1950s as a result of increased emigration. This decrease severely reduced the labour available for agriculture as many of the emigrants were young and quickly led to the deintensification of land use and later to the abandonment of agricultural land. Initially, migration was to other parts of Spain: Granada, Catalonia (for work in industry) and to other agricultural areas. With the development of tourism in the 1960s immigration to the coastal areas of the Costas and the Balearic Islands attracted increasing numbers. During the 1960s and 1970s large numbers of young men migrated to find work in France and Germany, staying for up to 15 years. Emigration was and is age and sex selective. Up to one-third of the men in Portugos interviewed by the authors had spent some time abroad during the 1960s and 1970s. More recently, alternative employment and part-time employment have become available within the villages, mainly in the tourism sector (bars, restaurants, hotels, tourist shops) and in the production of traditional foodstuffs and crafts. Young men have, again, been attracted to this type of work. The growth in the rural tourist sector has been locally rapid: in the Barranco de Poquiera, immediately to the west of this study area, the proportion of employment in the service sector has risen from 25 to 66 per cent between 1982 and 1992, with a commensurate decrease in the proportion employed in farming from 70 to 38 per cent (Gonzales Roa and Calatrava Requena,

Roc

k an

d sc

ree

Pior

nal

Mat

onal

Upl

and

gras

slan

d

Mo

rest

atio

n

Mix

ed o

ak w

oodl

and

Irrig

ated

mos

aic

Vill

age

km

Plat

e 1.

Lan

dsat

TM

fal

se c

olou

r com

posi

te o

f th

e A

lpuj

arra

stu

dy a

rea

(ban

ds 4

, 5 a

nd 3

on

red,

gre

en a

nd b

lue,

resp

ectiv

ely)

. T

he im

age

was

acq

uire

d on

17

Aug

ust

1992

. The

box

sho

ws

the

area

of P

late

2. S

ee te

xt fo

r a

desc

ript

ion

of th

e m

ain

land

co

ver c

ompo

nent

s. O

rigi

nal d

ata 0 E

SA (1

994)

. dist

ribu

ted

by E

urim

age/

NR

SC, F

ambo

roug

h.

mR

oc

k an

d sc

ree

0 iMa

tomal

0 Gra

ssla

nd

0 Mix

ed o

ak w

oodl

and

Irrig

ated

mos

aic

Unc

lass

ified

Vill

age

0 1

2

km

Plat

e 2.

Cla

ssif

ied

imag

e of

the

terr

aced

are

a su

rrou

ndin

g Po

rtug

os. T

he n

on-te

rrac

ed a

rea

and

the

villa

ge c

entr

es

have

bee

n m

aske

d ou

t. Th

e pe

rcen

tage

of t

he v

ario

us c

lass

es is

giv

en in

Tab

le I

.


1992). Clearly this recent trend is likely to have important implications in terms of agricultural deintensification and abandonment.

EFFECTS OF ABANDONMENT

Climatically marginal land at the upper limit was probably no longer sown even before the 1950s, but many farmers suggested in interviews during 1992 that the switch from cropping to grazing became most pronounced in the mid-1970s. Field observations in 1990, 1992 and 1993 suggest that the land least likely to experience deintensification is: land near the villages; larger terraces and land with gentler gradients; land with most improved soils; and land served by the lower m.

Many of the present farmers and farm workers are near retirement age so that abandonment of land is likely to continue and existing m will be abandoned. Household income rarely depends entirely on farming, but almost every household in the villages owns some land. Interviews in TrevClez and Pdrtugos (1992 and 1993) showed that there is an atavistic desire to maintain traditional farming methods even though the main source of family income is non-agricultural. In these cases, farming becomes little more than family vegetable gardening with a small surplus for sale, or the keeping of a few animals, particularly sheep and goats; in effect, a hobby that maintains contact with a peasant tradition. A decrease in the availability of labour is the main but not the only cause of deintensification. It might have been possible to replace labour with capital and mechanize farms; however, the relative poverty of farmers, the limited amount of level land and the small size of terraced fields have severely limited the scope of mechanization.

When land is no longer cropped it is available for other uses and is rarely directly abandoned. Even completely abandoned land has a use for hunting and rough grazing. As the main problem for farming has been the loss of labour, the succeeding land use will be less labour intensive. Especially if the land can still be irrigated, the field is likely to be let for grazing; nowadays grazing has become relatively more important than cropping. Terrace risers may continue to grow fruit trees for many years even if irrigation has ceased. Fruit trees are currently being planted in many of the fields that are no longer sown and, in some cases, for example near Pitres, vines have been planted. Though the general trend has been towards deintensification, there are cases in which the reverse has occurred: the best land is being used continuously with high inputs of dung, lime and artificial fertilizers. In Pdrtugos almost every household has some land which continues to produce vegetables for household use, again with high inputs of fertilizer. A second area of intensification is in soft fruit production in P6rtugos. Raspberries, loganberries and strawberries have been grown intensively during the last few years. The crop is high value but demands a large input of labour (ca. 400 hours ha-' y-'). Most of the village farmers grow raspberries and in consequence have less time for other types of farming, further increasing the tendency to deintensification elsewhere.

REMOTELY SENSED DATA

Landsat TM imagery has successfully been used to map land cover in several contrasting Mediterranean environments, for example, in Sicily (Khorram, er al . , 1991) and the Ardkche (MCgier, et al . , 1991). The Landsat imagery used in this study was TM quarter scene 200/34/4 (path/row/quadrant), acquired during cloud-free conditions on 13 May 1992 and 17 August 1992. These acquisition dates coincided most nearly with ground verification visits and provided multi-temporal data for the beginning and end of the growing season. The images from the two dates were geometrically co-registered to each other and smaller images of the study area (512 x 512 pixels) were extracted. For ground verification a number of different images were prepared, including a standard 453 false colour composite (see Plate 1). Other composites were formed from various band ratios, vegetation indices and principal component transformations, but the standard 453 composite was invariably found to be the most useful in identifying land cover variations in the field. The supervised classification of land cover was undertaken using a maximum likelihood algorithm and all six reflective bands from each date.


Plan of irrigation scheme

_-_-__---.

-~ Figure 3. Schematic plan of irrigation system northwest of TrevClez (after Liszewski and Suliborski 1977). The hierarchy of three levels of irrigation channel (m) i s shown for just part of the figure. The eight primary channels which were operative at the time of the survey (1973) occupy the slope from about 1800m to 1500m.

TREVELEZ CASE STUDY

TrevClez, at 1480m the highest village in Spain, was visited in April 1993 with a view to examining the land cover of the surrounding terraces. The pattern of population decline in TrevClez is typical of the Alpujarra with a maximum in 1950 of 1722, but only 877 in 1986 (Figure 2), the lowest figure since the 1760 census. The terraced area to the west of TrevClez has previously been mapped (Liszewski and Suliborski, 1977). At the time of the 1973 survey, the entire system, schematically depicted in Figure 3, was clearly in use with active irrigation and cropping on this particular slope up to 1800111. By 1993, however, much of this system had been abandoned, with irrigation in various stages of disrepair. This area was chosen for the present study to establish the potential of Landsat TM to identify changing land cover along a transect.

Irrigation waters are directed down to the lower slopes west of TrevClez from further north via and to the east of the village by a major a a a from the River TrevClez. Fields extend about

a kilometre above the village and the higher terraces are supplied by a number of major (primary) from the River Chico. The water supply continues almost throughout the year, being fed by

snowmelt on the slopes of MulhacCn. The uppermost of these major descends from a take off from the Chico at about 1800m. The distribution network is based on the construction of a stratified series of conducting water from the permanent stream sources along primary, secondary and tertiary channels (Figure 3).

above the uppermost terrace at 1900 m to Trevtlez at 1500 m identified four distinct areas. Simple estimates were made of the percentage cover of the dominant perennial species, with estimates of ground cover of grass, moss and small forbs and also exposed rocks. These assessments suggested clear differences in the vegetation cover in the four areas examined:

Rapid appraisal in April 1993 of a transect downslope from the area of


1.

2.

3.

4.

The semi-natural vegetation above the former extent of irrigation. Here the natural vegetation at the higher altitudes of the supramediterranean zone has been described as ‘vegetable hedgehog’ by Polunin and Smythies (1973), ‘hedgehog heath’ or and is characterized by low spiny shrubs capable of withstanding winter drought. These plants are often seasonally deciduous, chamaephyte species and include Vella spinosa and Ptilotrichum spinosum, Thymus vulgaris, T . serpylloides, Digitalis pupurea, Euphorbia spp. and Carduus spp., as well as grasses such as Festuca pseudeskia. They form a variable ground cover broken up by many exposed rocks. An area of abandoned terraces, no longer irrigated and currently being invaded by perennial species. There were well constructed terraces below the uppermost -a but there was little evidence of recent use at this altitude and shrub and bush species were invading. Secondary m were visible in the upper terraces but were well vegetated and therefore obviously little used. There were also threshing floors which have been abandoned. Terraces with little evidence of recent irrigation. There was clear evidence of grazing on the lower terraces, evidenced by animal droppings and temporary fencing. Well developed specimens of Adenocarpus decorticans and other shrub and tree species were present, particularly on the front walls of terraces. The terraces in this third area were wider than in the upper areas. Several terraces showed significant deposits of stones and sediments from collapsed m and terrace walls and were well vegetated with woody shrub species. Large tussocky grasses were also present, suggesting a low intensity of grazing. Terraces which are still maintained and cropped on a regular basis. These were found almost exclusively at the lower end of the transect. Characteristic crops included maize, barley, raspberries and vegetables. The threshing floors were still in use.

The natural succession of land after changes in agricultural management practices in Mediterranean systems has been discussed by Godron, et al. (1981), who suggest that m d and (types of scrub vegetation) would normally follow abandonment. With repeated cultivation annual herbs would be favoured. In the present context, where grazing has been practised on the upper terraces in place of cereal and other crop production, it would be expected that there would be an increase in the numbers of perennial and woody species and the development of a full ground cover.

This pattern of land cover changes can be identified through an examination of the remotely sensed data. Values of a simple vegetation index (TM 4/3 ratio) are plotted in Figure 4 for the transect. They reveal a progressive increase in values with a decrease in altitude in response to the increased vegetation cover. The lower values of the index at the top of the transect for the August 1992 acquisition date show the effect of the summer drought on the and abandoned terraces. Lower down, the effect of cropping and leakage from d, promoting flushes, has given a spiky appearance to the data. The simple classification system, adopted to represent the digital TM data, characterizes the uppermost zone and the abandoned terraces as -1, the actively grazed terraces as grassland and the cropped area as irrigated mosaic. It is clear that the land use along this transect has changed substantially since the 1973 survey. Local information points to the abandonment of the uppermost terraces about 15 years ago (i.e. in the late 1970s). Since then the effective margin of cultivation has dropped from 1800 to about 1600m, so that only the broader, lower terraces are currently being sustained for agriculture. In a very real way this transect shows as a spatial sequence the temporal pattern of abandonment and deintensification over the last 20 years.

PdRTUGOS CASE STUDY

Portugos comprises parts of the of La Taha (Pitres and Mecina Fondales), P6rtugos and Busquistar. This area was selected for estimating the areal extent of deintensification for several reasons: (1) it represents a large contiguous area of terracing at characteristic altitudes for the Alpujarra (between 900 and 1500m); (2) the lower altitudes include the upper limits of the thermomediterranean zone in which citrus grows; (3) the majority of the area is within the mesomediterranean zone and includes the

T. D. DOUGLAS E T A L .

Ddncenslfkd Terracea 1nlgrt.d Mouk

I Iprarrlandl

288

5

4

0

K z 0

2

2

-1 Abrndomd Terraces

I -a -- 4/3 Ratb 13 May 1992

A 413Rrck 17 Aug lS92 -_ - - . -. -. .

1- - .1--------1 - -~ . . . ,._ .----

op of transect (1900 m) b Trevelez (1 500 m) Figurc 4. Transcct across irrigated zone schematically illustrated in Figure 4 to the west of TrevClez showing Landsat TM band 413 ratio

usual upper limit for the olive; (4) the highest portions abut the supramediterranean zone; (5) the altitudinal range is significant for tree crops, throughout the m n zone; (6) the area is characteristic of the non-agricultural land that has become re-established on terraces which have been abandoned (as at May 1991); and (7) the area has roughly uniform illumination, with slopes facing between south and southeast, and thus it avoids most of the problems associated with topographic shading as a result of the high relief (Plate 1).

Over 30 training sites were identified from field survey in April and September 1992, representing a range of land covers. The irrigated terraces were used for several types of crops, with irrigation water applied from the beginning of April. Maize and wheat were common crops, but vegetables and soft fruits were locally important, and tree crops were often grown on terrace fronts and increasingly on terrace surfaces. At the time of the first data acquisition, 13 May 1992, most crops were actively growing where terraced land was in use. However, by 17 August 1992 some crops had been harvested and in a few cases the land had been ploughed. It was clearly necessary to use TM bands from both dates for adequate classification of this irrigated mosaic class. As in the preceding case study of TrevClez, although the irrigated mosaic class represents those terraces which are still actively cultivated, at least two classes of deintensification can be recognized: firstly, the end of cropping and the invasion of grasses and herbs, often colonizing from adjacent terrace risers; and, secondly, the invasion of m- species to provide a denser cover and nearly always marking an end to irrigation. Although many intermediate categories can be recognized in the field, these two classes are used to represent this continuum in the classified image. The remaining classes represented in Plate 2 include coniferous and oak woodland (predominantly in riparian situations alongside steep-sided m s ) and bare rock outcrops.

The terraced area was identified and mapped from field survey and a 1:10O00 map and the surrounding non-terraced area and village centres were masked off. The results of the classification are shown in Table I and show that over 64 per cent of the terraced land is still actively used for agriculture. Plate 2 shows that it is in the vicinity of Pitres that the irrigated terrace mosaic is least extensive, with large areas of terrace now falling into the grassland class and an extensive area of m d in the southern periphery of the area. A future phase of this study will seek to disaggregate this information by -0, but it is instructive to note that for the -0 in which Pitres is located (La Taha), the infrastructure for

TERRACE ABANDONMENT IN THE ALPUJARRA

Table I. Classification data from bands 1,2,3,4,5 and 7 of May and August 1992 TM imagery of Portugos area

Class Number of Area Percentage of

Colour pixels (km’) image

Coniferous woodlands Oak woodlands M m l Imgated mosaic Rock Grassland Unclassified Total

Dark green 22 0.02 Light green 118 0.12 Brown 1703 1.66 Red 6367 6.22 Purple 11 0.01 Yellow 161 1 1.57 Black 13 0.01

9845 9.61

0.21 1.25

17.27 64.72 0.10

16.34 0.10

99.99

289

clearance Semi natural oak ,

woodland

crops abandoned, grazed when not grazing continued

cropped irrigation abandoned

\ high intensity

clearance and coppicing for wood

and charcoal

/ reduced grazing land grazed intensity

\ low intensity

tree crops continue on terrace edges

planting of unirrigated trees (eg

olives. vines)

limitid human interference m m reafforestation ,

I

Figure 5. Schematic model of deintensification of terraced agriculture in the Alpujarra

- conservation (?)

Semi natural oak woodlan

rural tourism is better developed than the P6rtugos or Busquistar, the inevitable corollary is that fewer households remain dependent on the established farming system for their livelihoods.

CONCLUSIONS AND POLICY FRAMEWORK

Figure 5 relates the changing land use of the study area to the present land cover units which have been used in the classification. The land cover classes on the right-hand side of the diagram correspond to those of the image classification used in this study. The dimensions of many of the terraces are smaller than the 30m resolution of Landsat TM. As the TrevClez transect shows, land which was clearly in use

290 T. D. DOUGLASETAL.

20 years ago has now been sufficiently deintensified or abandoned to take on the broad spectral characteristics of the F I or grassland classes. The trend, particularly at lower altitudes in the study area, to plant tree crops on formerly cropped terraces has not been fully considered here. Most tree crops (irrigated or not) are currently classified under the irrigated mosaic class. The process of classifying the tree crops as a separate class is further complicated by the regular use of terrace edges as sites for growing almonds, apples, walnuts, etc.

Clearance of semi-natural oak woodland has occurred discontinuously from prehistoric times up to the present. Many of the processes such as abandonment of irrigation, reafforestation with conifers, conversion to grazing land and planting of unirrigated trees are still occurring, as is reversion to m m and oak woodland. Many parts of the irrigated mosaic have been stable for over 500 years, yet monitoring over the next few years may reveal an acceleration of deintensification as fewer people obtain a living from agriculture.

Land use in the Alpujarra must be interpreted in the light of decision-making by individual farmers, farming households, groups of farmers (for example in co-operatives), local communities, in particular the bjgntamiento and locally controlled irrigation organizations, all of which act in a macro-framework determined directly or indirectly by market conditions and policy-makers. The EC acts both directly through its Agricultural and Social Policies and indirectly, mediated by a hierarchy of Spanish ministries, regional and local governments. Four examples illustrate some of the effects of these policies. Firstly, the villages fall within one of the Less Favoured Areas of the EC and consequently are eligible for compensatory payments related to the adverse production conditions. This is in the form of grants through the Common Agricultural Policy to support crop production, for example for maize, wheat and other cereals produced on small farms. Secondly, as part of the Integrated Mediterranean Programmes, grants are available to encourage conversion to the production of oil seeds and other marketable crops. Thirdly, the Junta de Andalucia, in the Andalucian Forestry Policy (Agencia de Medio Ambiente, Junta de Andalucia, 1989) has identified the Alpujarra as one of the areas where they will, over a long time- scale, encourage the abandonment of marginal farms through the set-aside mechanism, with eventual conversion to forest. Fourthly, through the LEADER Plan, (first phase 1991-5), the EC is giving grants for agricultural improvement, the development of tourism and for artisan workshops in the Alpujarra (in practice, most of the grants have gone to small tourism developments and few to agriculture). As tourism developments will support family income, it is likely that the general effect will be to help maintain agriculture on the terraced land. Overall, the medium-term effect of these various policies is likely to be the maintenance of cropping on the terraces and a slowing down of the rate of conversion. In the long term, deintensification is likely to continue with conversion of the most marginal land to forest, though not necessarily to coniferous forest. It is conceivable, in the absence of any counteracting policies, that the villages could ultimately, like some of those in the Contraviesa, be completely abandoned. This does not seem likely if tourism continues at its present level. It seems likely that there will be more tourism, second homes and increased importance for grazing and complete abandonment of marginal areas. Tourism, however, will probably not be sustainable if the landscape were substantially reforested.

This study has illustrated the way in which TM data can be used to characterize the land covers which are indicative of deintensification and abandonment of terraced areas. The techniques need to be fully validated by extension to other areas, but they point the way to a more comprehensive assessment of the status of agricultural terrace abandonment, not just in a few -s, but throughout the Alpujarra region. Integrating the remote sensing assessments of land cover with population statistics at m-o level in a geographical information system should enable a clearer explanation of the links between the ecological status of terrace deintensification and some of the causative factors.

REFERENCES

Agencia de Medio Ambiente 1989. Informe 88: Medio Ambiente en Andalucia, pp. 223-239, Junta de Andalucia, Seville Brenan. G. 1957. South from Granada, Cambridge University Press, Cambridge.


Godron. M., Guillerm. J. L.. Poissonet, J.. Poissonet, P., Thiault, M. and Trabaud, L. 1981. Dynamics and management of vegetation. pp. 317-344 in F. Di Castri, D. W. Goodall and R. L. Specht (eds.) Ecosystems of the World, Vol. 11. Mediterranean- type shrublands. Elsevier, Amsterdam.

Gonzales Roa. C. and Calatrava Requena. J. 1992. Le d6veloppement du tourisme rural dans les hautes Alpujarra, in G. Bazin and B. Roux (eds.) Les Facteurs de Resistance a la Marginalisation dans les Zones de Montagne et Defavorisdes Mediferrandennes Communautaires, Commission of the European Community, DGVI, AS, No. P262.

Khorram, S., Brockhaus, J. A. and Geraci, A. 1991 ‘A regional assessment of land-uselland cover types in Sicily with TM data’, Infernational Journal of Remote Sensing, 12(1), 69-78.

Liszewski, S. and Suliborski, A. 1977. ‘Colonisation et Cconomie en haute montagne: Trevtlez (Sierra Nevada, Espagne)’, Mdditerrande, 1, 65-72.

Mpez Bermudez, F. 1990. ‘Soil erosion by water on the desertification of a semi arid Mediterranean fluvial basin: the Segura Basin, Spain’, Agriculture, Ecosystems and Environment, 33, 129-145.

May, T. 1991. ‘Siidspanische Matorrales als Kulturfolge-Vegetation’, Geodkodynamik, 12, 87-107. McNeill, J. R. 1992. The Mountains of the Mediterranean World: an environmental history, Cambridge University Press, Cam-

Mkgier, J., Hill, J. and Kohl, H. 1991. ‘Land-use inventory and mapping in a mountainous area: the Ard6che experiment’,

Molero Mesa, J., Ptrez Raya, F. and Valle Tendero, F. 1992. Parque Natural de Sierra Nevada, Editorial Rueda, Madrid. Polunin, 0. and Smythies, B. E. 1973. Flowers of South-west Europe, Oxford University Press, Oxford, 480 pp. Quirantes Puertas, J. 1987. ‘Guadalfeo el medio y el hombre’, Instituto Nacional para la Conservaci6n la Naturaleza, Madrid,

Thornes, J. B. 1976. Semi-arid Erosional Systems (London School of Economics Geographical Paper No. 3, London School of

bridge.

International Journal of Remote Sensing, 12(3), 445-462.

Proyecto Lucderne 111, pp. 93-174.

Economics, London.

Documents

Agricultural terrace abandonment in the alpujarra, andalucia, spain