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Recep EFE Department of Geography, Fatih University, Istanbul-Turkey ABSTRACT The coastal zone between Küçükkuyu and Edremit has special value from the viewpoint of biodiversity due to the variety of plant assemblages demonstrated. Anthropogenic factors play an important role in the degradation of natural vegetation (i.e., land use practices have changed in the last two decades along the coastal zone in the Edremit area). In particular, these changes have accelerated over the last five years (between 1995-2000). New settlements were and are being established on land that was once used for agriculture. Natural vegetation has been cleared to make room for the construction of second homes and vegetative cover is under heavy urbanization and touristic pressure throughout the northern part of the Gulf of Edremit. Locally dominant species such as Olea oleaster and Pinus brutia are the major plants that have been affected by on-going human interventions in the area. INTRODUCTION Turkey is one of the richest countries in the world regarding the biodiversity of its flora. The number of plant species exceeds 10.000 (including subspecies and varieties). The number of taxa of Turkish flora (all of the steps in the plant hierarchy such as family, genus, species, subspecies and variety) is closer to the number of taxa found represented in all of Europe (Gemici et al., 1992). The Gulf of Edremit has been populated for thousands of years (Ramsay 1890, Balcıoğlu 1937, Derin 1968, Stewig 1968). Issues of contemporary environmental change in the Mediterranean ecosystem and their association with desertification remain controversial in many respects due to their multifaceted social and environmental dimensions. Desertification is described by the UN Convention to Combat Desertification (CCD) as "land degradation in arid, semiarid, and dry subhumid areas resulting from various factors, including climatic variations and human activities." In this context, land includes the soil and water resources, as well as natural vegetative cover upon which rural agricultural livelihoods are dependent. Degradation implies a reduction of the resource potential by one or a number of processes operating on the land (Midleton and Thomas 1997). One study has defined desertification in this context as "an effectively permanent decline in the rate at which land yields agricultural products under a given management system" (Abel and Blaikie 1989: 113). This study has characterised the loss of biodiversity plus soil erosion associated with the intensification of land use change over the last thirty years in the Gulf of Edremit and its environs. Geography and physical characteristics : The study area is situated on Turkey's western coast. It extends from Küçükkuyu eastward to Altınoluk, Güre, Akçay and Edremit. It is located in the Aegean region geographically and the Mediterranean region phytogeographically. The Gulf area has a Mediterranean climate with a mean annual precipitation rate of 660 mm, the majority of which falls between October and March. The area experiences two seasons: wet mild winters, and dry hot summers, which are the main characteristics of the Mediterranean climate. Winter, the low sun period between October and April, is wet, and the summer period between May and October is dry. Only 3.5 percent of total annual precipitation occurs during the summer period. The average annual temperature is 15.7 oC and summer temperatures rise to 30 oC in July and decrease to 6 oC in January. This temperature regime is found only along the narrow coastal zone. The slopes and higher parts of the Kaz Mountains are cooler in summer and colder in winter. Tropical air masses, which come from the south, are influential concerning local climate. The Kaz (Ida) Mountains on the north of the Bay of Edremit lie in an east-west direction, and serve to block the cooler air masses coming from north. Prevailing winds from the southwest bring wet air from the Mediterranean and Aegean seas. Soil types include the Inceptisols and Entisols (whose horizons are not well developed). Relatively short rivers rise from the Kaz Mountains, drain the area, and flow to the Aegean Sea. The Mıhlı, Koca, Manastır, Kuru, and Çehiz rivers are the main water courses and flow down the steep slopes of the Kaz mountains These rivers transport run-off and soil materials, and deposit them in the lowlands forming alluvial fans and small deltas. The coastal plain to the east of Ilıca is joined to the Edremit plain. The rolling hills on the north of Küçükkuyu developed on sedimentary rocks belonging to the Upper Miocene. There are igneous rocks on the east that form the small hills. Metamorphic rocks are represented by marble and schist on the slopes of the Kaz Mountains. MATERIAL & METHODS This paper examines the interactions across scales and across time between changes to vegetative cover and increasing human intervention. A variety of information and analytical methods are employed, including analysis of air photos and field surveys of vegetation change. Topographical, vegetation, and forest management maps were used to characterise the distribution of natural vegetation in the past. The present situation in the field was studied through direct observation. Plant samples were collected from the study area in different seasons between 1998-2000. Photographs were taken in the summer and winter seasons in order to observe the difference in terms of deciduous and evergreen plants. Vegetation studies were carried out along 5-km transects starting from the sea. Sampling was based on 20x20 study sites located between the Aegean Sea and the Kaz Mountains. Plants were collected from the area during summer of 1999 and the winter of 2000. Climatological data was taken from the General Directorate of Meteorology. DISCUSSION Three types of vegetative formations were observed in the study area. Forest formations are widespread on the slopes, and maquis and garrigue cover the lowlands and gentle slopes. Red pine (Pinus brutia) and oak (Quercus infectoria) are the dominant species in the forest formations. Maquis is another form of native vegetation in the area and is a cover of drought-resistant shrubs, including sclerophyllous and spiny-leaved species. Forest, maquis and garrigue vegetation are interspersed together throughout the study area. Dry forest : Dry forest begins at the margins of agricultural land and it extends to the Kaz mountains. This formation is spread extensively throughout the southern slopes of the Kaz Mountains between the altitudes of 200 to 700 meters. Red pine (Pinus brutia), Gall oak (Quercus infectoria), Valonia oak (Quercus ithaburensis ssp. macrolepis) and Turkish oak (Quercus cerris) are the most common species in the dry forest formation. Undergrowth does not demonstrate much variety and downy cistus (Cistus creticus) is the most common species under the tree layer. Compared to Pinus brutia, Quercus infectoria and Quercus cerris show a restricted distribution on the slopes between Akçay and Altınoluk. Characteristic and differential species of this forest include the following: Pirus elaegrifolia, Prunus spinosa, Crataegus monogyna, and Carpinus orientalis. Maquis vegetation : This formation usually occurs on the slopes between 100 to 500 meters and includes the following: Olea europaea, Arbutus andrachne, Arbutus unedo, jasmine box (Phillyrea latifolia), terebinth tree (Pistacia terebinthus), and storax (Styrax officinalis), Maquis formation consists of the following: kermez oak (Quercus coccifera), prickly cedar (Juniperus oxycedrus), broom (Spartium junceum), (Phillyrea latifolia), laurel (Laurus nobilis), wild olive tree (Olea europaea var. oleaster), (Pistacia terebinthus), strawberry tree (Arbutus unedo), and oleander (Nerium oleander). The maquis vegetation is adapted for survival through long summer droughts. These sclerophylous plants are typically equipped with small, hard or thick leaves that resist water loss through transpiration. Maquis vegetation of the coastal zone and lower slopes is replaced by red pine forests at about 500 meters. The coastal area was originally covered with vegetation consisting of maquis elements, oak and red pine. However, previous stands of this vegetation have been replaced by human practices (e.g., agriculture) and development. Garrigue formation : The garrigue covers the degraded areas. The garrigue elements are hardy, and therefore more resistant to the stress caused by human activities and the local climate. The coastal zone between 0-400 meters was originally forested, but much of the land was cleared for human uses. Consequently, the assemblages of the plant cover have changed with extensive clearing and soil erosion has accelerated on the slopes. Degraded and abandoned lands have been invaded by garrigue elements. Soil types and vegetation : Inceptisols and entisols are weakly developed soils occurring in the study area. The most developed zone is the A horizon. The pH of these soils varies from 6 to 7.5 and they lack clay. Entisols, which lack distinct horizons, occur on steep slopes and lowlands. Soil characteristics are not a factor for explaining changes in the vegetation community structure. Soil fertility in lowland areas of the region is high since nutrients that are essential to plant life have not been washed out of the soil. Conversely, soil erosion induced by human activities have lead to extensive land degradation at higher altitudes. Many slopes have been denuded of their soils and are barren. Sediment, representing the displaced soil, has formed thick layers of sand and silt in adjacent valley floors and the coastal zone. The coastal zone alongside the Aegean Sea is rich in terms of Halophytic and Psammophytic species. Representative Halophytic plants consist of Arthrocnemum fruticosum, Halocnemum strobilaceum, Juncus aculatus, J. maritimus, Tamarix parviflora and are common on salty soils on the lowlands close to the sea. Ammophila arenaria, Cakile maritima, Centaurea spinosa, Euphorbia paralias are the species widespread on sandy areas (Güvensen et al., 1996). The construction of touristic facilities like hotels, motels and pansions is inducing the displacement and local extinction of some of these plants. Human impact on vegetation : The area is predominantly covered with Mediterranean vegetation consisting of Red pine (Pinus brutia) and maquis (Olea eorepea, Pistacia terebinthus, Phillyria latifolia, Quercus coccifera etc.) elements. The past thirty years have witnessed accelerated changes in natural vegetation because of increasing human pressure. Vegetation community changes are clearly associated with human activities (e.g., emerging agricultural patterns and tourism). The driving forces behind this conversion include changes to agricultural market demand, tourism, road construction and settlement growth into forested and agricultural areas. Privately-owned parcels are being used for building second homes and touristic facilities. Ecological integrity and biodiversity remains high within healthy sites. It is the maintenance of this biodiversity, in terms of both bush and grass cover, that can explain the observation that, as yet, ecological changes have not significantly reduced agricultural production. Vegetation changes are often reversible, such that even systems classified as severely degraded demonstrate rapid recovery characteristics, especially following the return of good rainfall after dry summers. Nevertheless, degraded land is losing soil faster than it can be formed. The agricultural community is trying to compensate by employing fertilizer and by increasing irrigation. However, the potential yield from prime agricultural land has dropped by as much as 20% in the last 20 years. Much of the land along the coastal zone is being harnessed for agricultural activities, touristic development and residential development pressure. There is an on-going threat that second home development on existing agricultural land will cause a marked decline in the local productivity of olive and tangerine orchards. Land use change is basically a process of land degradation driven by socio-economic forces, often working synergetically with vegetation change. This process is occurring continually in the Edremit Gulf area. The purpose of this study is to explore the dynamics of changes in the area, paying particular attention to the confrontation between sustainable development and attempts to increase the amount of land under cultivation and the land facing development. It is clear that anthropogenic factors play a key role in degradation of natural vegetation, since human structures have been built on the areas that were once strictly occupied by forest (Pinus brutia) and shrub (maquis) vegetation cover. Economic forces have extensively modified the use of the land, stripping away natural vegetation to build second homes, hotels, motels and pansions. Therefore, the natural vegetation consisting of Mediterranean elements such as Pinus brutia, Olea eorepea, Pistacia terebinthus, and Phillyria latifolia, kermez oak (Quercus coccifera) have been cleared. Land use changes are accelerating the evolution of the ecosystem. There has been successional change in ecosystem status starting in the 1950s when the olive (Olea europea) areas started shifting from the coastal zone to inland. The olive cultivation areas were replaced with second homes and available land for new homes is being gained on the slopes by clearing the red pines. Simultaneously, further disturbances resulting from human activity include cutting and clearing the red pine forests to use the land for olive cultivation and thereby removing the climax vegetation on the higher slopes. The maquis vegetation occupying the slopes between 100 to 500 meters has been replaced by olive trees. These factors, in combination, explain the rapid and intense degradation of Mediterranean vegetation cover. Findings show a common pattern of change in natural vegetation and ecological degradation consistent with altitudinal stratification and increases in the intensity of land use. Four indicators related to land use change are developed: land resource availability, land use productivity, loss of biodiversity, and ecosystem stability. The higher slopes in the study area are being used for olive cultivation, which is not a suitable location for this activity. The shift from maquis and red pine to olive trees and clearing the Pinus brutia on the slopes increases erosion and induces land degradation. The other important factor in changing the area is increasing demand for second homes. The Mediterranean climate is extremely attractive for human habitation. This attraction lies in the thermal cycle of year-round pleasant temperatures, especially where moderated by coastal influences. In summer, the regional population increases by over 100 thousand people. As Table 1 demonstrates, this represents a substantial influx of temporary local residents over and above permanent residents.  In the Edremit Gulf area, land degradation is driven by the socio-economic forces that cause land use to evolve, and works synergistically with vegetative change. Successional change in the ecosystem starting from 1970s and continuing has been demonstrated. The Olea eropea cultivation areas shifted from the coastal zone to inland. The resilience of the ecosystem's ability to recover from disturbance is very low in the Mediterranean climatic zone, in part, due to the low precipitation levels and high temperatures experienced in summer. It is clear that anthropogenic factors play a key role in the clearing and degradation of natural vegetation, since human structures have been built on the area that once were strictly natural habitat. Olive and tangerine cultivation areas have been replaced with both urban and rural development. Available land for the construction of new homes is being gained on the slopes by clearing red pines. Consequently, the clearing of natural vegetative cover and other land use practices has accelerated ecosystem change. CONCLUSIONS Over the last few decades, housing demand has added pressure to the ecosystem as forests have been cleared for building second homes and for olive cultivation. Natural vegetation areas consisting of Mediterranean elements such as Pinus brutia, Olea europaea, Pistacia terebinthus, Phillyria latifolia, and Quercus coccifera have been extensively cleared. The slopes at higher altitudes are being used for olive cultivation, which is not suitable for this land use. The shift from maquis and red pine to olive trees and clearing the red pine (Pinus brutia) on the slopes increases erosion and induces land degradation. Human activities (e.g., monoculture) have simplified plant communities by eliminating biodiversity and causing land degradation. The ability of the ecosystem to recover from disturbance (resilience) is low because of the characteristics of the Mediterranean climate (i.e., hot, dry summers). REFERENCES Abel, N.O.J., and Blaikie, p.M. (1989) Land degradation, stocking rates and conservation policies in the communal Rangelends of Botswana and Zimbabwe. Land degradation and rehabilitation 1:101-123. Atalay, İ. 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