Article Type: Research Article

 

Article Citation: Faiza Khebour Allouche, Saida Hammami, Arwa Hamaideh, Emna Gatta, and Anas Khasawneh. (2021). ENVISIONING SUSTAINABLE LANDSCAPE MANAGEMENT IN THE ENVIRONMENTALLY SENSITIVE AREAS OF KSOUR ESSEF, TUNISIA. International Journal of Research -GRANTHAALAYAH, 9(1), 85-98. https://doi.org/10.29121/granthaalayah.v9.i1.2021.2715

 

Received Date: 11 December 2020

 

Accepted Date: 27 January 2021

 

Keywords:

ESA

Landscape

Diagnosis

Urban Natural Park
ABSTRACT

Each territory has distinctive features and landscape compositions that contribute to the creation of territorial identities. Natural parks are territories remarkable for their wealth of biodiversity, which in turn contribute to the development of sustainable socio-economic development through landscape enhancement. The main idea of this research is to test the combinaison of two concepts to propose a suitable management in a semi-arid environment. It is based on the use of the ESAs and landscape diagnosis concepts. The concept of ESAs is supported including the need to identify environnementally sensitive lands based on the hypotheses of MEDALUS project model. However, the landscape diagnosis is based on the combination of landscape potential and social requirements. Results aimed to create ecological and environmental models based on natural materials such as wood, light minerals and a diversified and multicoloured plant palette, including the logic of working with nature and preserving its particularity by promoting sustainable local development criteria and create a new green city.

1.     INTRODUCTION

 

Since the early 19th century, forests have been the scene of urban growth and have sometimes been transformed into green and wooded areas or urban forest parks. With the evolution of large urban areas, the need for space for new construction has caused problems following deforestation, fires and the degradation of peri-urban natural areas. Today, despite these disadvantages, several countries have become more aware of and respectful of peri-urban forests through the development of fields of activity in these areas. Forests are multifunctional spaces, offering both tangible and intangible services. In Japan or Australia, the demand for recreational spaces has encouraged public authorities and local authorities to invest in forests to benefit from their environmental and social functions. In France, the social perception and representation of forests are very closely linked to leisure activities (Papillon, 2014).  In Tunisia, peri-urban forests were transformed into public parks in the summer following the program of 100 parks that began in 1996. The objectives of creating these parks are essentially to improve the living conditions of city dwellers and to preserve the natural spaces adjacent to the cities. Among the forests that have been transformed into public parks are (Nahli, El Mourouj, Farhat Hached, El Hmeda,...).  Today, these forests converted into peri-urban parks do not meet society's needs for a pleasant natural living environment and also for leisure. Peri-urban forests require new recognition and also a rethinking of their future. The example of the Ksour Essef peri-urban park is our study support, in order to assess its current state and propose solutions that can remedy the disadvantages and offer the target population a better living environment in order to preserve natural resources while meeting the requirements of sustainable development. Generally, landscaping projects are based on landscape analysis, this research work consists in presenting a method of evaluating the landscape features of a regional forest natural park which has been developed in 2011 but has undergone a significant degradation of natural and managed entities following the effect of climate change and anthropogenic especially after the revolution. The status of sensitive environmental areas will be assessed by applying the Medalus method. Then, a landscape diagnosis is carried out on the ground. The comparison of the results will enable to better manage the studied space and propose a sustainable landscaping taking into account the three pillars of sustainable development.

 

2.     STUDY AREA

 

The park is located in the delegation Ksour Essef belongs to the governorate of Mahdia and occupies an area of 16 hectares which implanted in a forest of an overall area of ​​50 hectares (Figure 1). This space was actually an old stone quarry in the sixties, which after its closure in 2001, was promoted as a green space. It occupies the highest point of the city whose altitude can reach up to 66 m. This forest represents the green lung of the city, thus, it is formed of an afforestation of Aleppo pine "Pinus Halepensis" and Eucalyptus "Eucalyptus Camaldulensis". The development of the park is part of the national parks program that brings together 100 parks throughout Tunisia to improve the living environment of the population and the protection of the environment. It was open, according to the municipality of Ksour Essef, in 2002 and was valued as a forest park. Indeed, a wrought iron fence was put in place to demarcate the park and protect it with an entrance gate made by AUDEC (2002), with a sum of 28 thousand dinars. Inside the park, a fitness trail was set up in 2011 with all the physical work equipment, a refreshment bar, a play area, a "LABIB" pedestal and family rest areas with benches. But since the Tunisian revolution, in 2011, the space was destroyed and poorly maintained, therefore, it became non-functional and a wealth of landscape was lost including the components of the course.

The delegation of Ksour Essef belongs to the governorate of Mahdia located south-east of the Tunisian sahel, 200 km from the capital Tunis and 12 km from the city of Mahdia with an area of ​​40 Km² and 54 366 inhabitants in 2014. It is located on a moderate hill, and encloses a coastal zone stretching 13 Km (Figure 1). According to the National Meteorological Institute of Tunis (2017), the city of Ksour Essef is known for a warm, dry Mediterranean climate in summer, humid and temperate in winter with a maximum average temperature of 31 ° C and a minimum average of 6 ° C. The city is also known by winds on the east side in summer and on the west side in winter, whose west winds are dominant and can reach up to 80 m/s. Potential evapotranspiration (PET) varies from 1319 to 1321 mm / year in 2010. According to the Regional Commissariat for Agricultural Development (CRDA, 2014), Ksour Essef contains the water table "Melloulech", where 1446 water wells produce 2.91 million m³/year with a variable salinity between 3 to 15 g/l. It belongs to the "Sahel Sfax" water table, consisting of 22 water wells, producing 3.15 million m³ of water. The Territorial Extension Cell (CTV, 2002), has mentioned that the irrigated perimeters at Ksour Essef occupy a total of 110 hectares spread over 152 farmers. It despites a water salinity of 4.3 g/l of salt. However, Ksour Essef is built on a succession of hills with altitudes that vary between 6 m and 30 m and the neighboring altitude hills reaches 65 m.

Figure 1: Location of Ksour Essef city, Tunisia

 

The delegation of Ksour Essef is home to several types of soils, and the predominance of low input soils, isohumic soils and raw mineral soils on the north side. In the southern part, the soils are raw limestones, while in the center there is a diversity such as halomorphic soils, rendzines and complex units. The raw mineral soils are located on a steep slope where the surface layers are constantly entrained thus preventing the formation of soil from which the vegetation cover is very insignificant. This type of soil is mainly present in the northern and north-eastern part of Ksour Essef, with a succession of hills reachs 66 m. The poorly evolved soils are generally located in semi-arid areas, characterized by a low degree of weathering, a humic horizon and a structure that is often weak. Isohumic soils are characterized by a dominance of clays found in the forest of Ksour Essef (Figure 2). The land use of the town of Ksour Essef is subdivided into two parts: the coastal side presents a variety of crops including cereals (barley and wheat), forage crops (sorghum, maize, oats ...), market gardening (pepper, tomato, potato, zucchini, cucumber, carrot, onion, melon, eggplant, pea, squash, watermelon, garlic ...), spices (cumin, choriambe) and olive groves. Further, cereal crops persist in the west one (Figure 3).

 

 

The commune of Ksour Essef, contains 12 green spaces with a total area of ​​353,950 m² distributed as follows:

·        Habib Bourguiba Street Garden: 2500 m² (under redevelopment)

·        Hedi Chaker Street Garden: 1850 m² (in redevelopment study)

·        Ahmed Tlili Street Garden: 1,800 m² (requires maintenance)

·        Omar Karchoud Street Garden: 400 m² (requires maintenance)

·        Ali Bouzidi Street Garden: 2000 m² (in redevelopment study)

·        El Hmeda Park: 160 000 m² (in redevelopment study)

·        Garden Aziza Othmena street: 78 300 m² (corner bush)

·        Garden rue Salah Eddin El Ayoubi: 20 100 m² (corner bushed)

·        Garden Bizerte street: 8200 m² (bushed area)

·        Garden Jbal Khmir street: 78 400 m² (corner bush)

·        Garden Street 2 Mars: 300 m² (in redevelopment study)

·        Garden street Abdallah Chaweli: 100 m² (corner bush).

 

The delegation of Ksour Essef has a population of 54,366 inhabitants in 2014. The economic development of the city of Ksour Essef is based on the trade where there are more than 300 points of sale in detail. The participation rate is 38.87 % while the unemployment rate is 9.83 %, which shows that despite the reduction in the number of jobs in the city, agriculture and commerce provide a lot of jobs (INS, 2014). During the last five years, the city has undergone remarkable development especially in the administrative, health, educational, sports, cultural, religious and commercial (Monoprix, Carrefour, etc.).

 

3.     METHOD

 

Urban Natural Parks are designed to preserve and improve the quality of the landscapes and the living environment of the inhabitants. As a result, the need for green spaces in cities is becoming a necessity, and city dwellers are looking for moments of relaxation, rest, recreation, outdoor activities and sports where nature is very calm.  In this strategy that the municipality of Ksour Essef has requested a proposal for the redevelopment of the El Hmeda natural urban park, which is part of the sustainable development project of Mahdia city.  In response to this request, the objective of this research is to propose a landscaping redevelopment in this park.  The methodological approach is based on the ESA approach and the landscape analysis dealing with the different physical, sensitive and natural aspects and the development proposal is based on the concept "Treasure Hunt". In order to understand and act effectively on the Ksour essef park, we opt for an analytical approach based on diagnosis and evaluations, as shown in Figure 4, different steps followed in the methodological approach.Two principal steps are used the landscape diagnosis and the ESA assessment of park El Hmeda

The physical diagnosis is based on the use of Google earth, open street map and some shapefiles. Google earth and field validation using GPS are done for digitizing and mapping the spatial delimitation of the park, slope and altitude variation for two transects, it’s land use cover and field description of some stations. The park accessibility is mapped using Open street map tool and some benchmarks are located. However, sensitive analysis is based on the visual interpretation of the landscape structure (vertical and horizontal), noise, and colors in order to evaluate its state. The survey conducted as part of this research, aims to know the expectations of the resident population around the forest of El Hmeda and visitors to approve our idea of ​​design. Ten questions in total were asked, out of 50 people, some are asked in a socio-economic context such as age, sex, the budget devoted to leisure, the distance between the park and the housing of the person surveyed. Others are asked to better understand the strengths and weaknesses of the space, the reasons for the visit, the preferred locations and the expectations of the new landscaping.

The use of this diagnosis method is based on the hypotheses of MEDALUS project model (Giordano et al., 2007). Three qualitative indexes are computed by applying an average of a geometrical model. The following three quality indices were computed;

·        Soil Quality Index (SQI),

·        Vegetation Quality Index (VQI)

·        Climatic Quality Index (CQI)

 

Administrative, land use land cover and sol Mahdia vector layers are used to map and calculate indexes. DEM raster layer was downloaded from https://glovis.usgs.gov/ and used to retrieve the slopes and aspect gradients. The data (spatial resolution of 30 m). The evaluation of ESAs is based on a combination of the physical including soil, climate, and vegetation qualities. A geodatabase and several thematic maps were prepared and standardized with the same projection system and spatial resolution. The indicators were grouped into four quality indices, namely, the soil quality index (SQI), climate quality index (CQI), vegetation quality index (VQI), and MQI (Khebour Allouche and Gad, 2014). Each indicator was calculated by means of sub-indicators, which were also classified. For each class, a weight value was allocated. The values of the weights varied from 1 (least sensitive to desertification), to 2 (most sensitive to desertification) (Gad and Lotfi, 2008).

Figure 4: The landscape diagnosis and the ESA assessment of park El Hmeda, Tunisia

 

3.     RESULTS AND DISCUSSION

 

3.1. ASSESSMENT OF SENSITIVE AREAS

 

A large part of the park is located in a quaternary formation. The quaternary part includes terraces of major bed, mobile sand, unconsolidated scree, low terraces, dejection cones, and white limestones, probably lacustrine and often conglomeratic. Furthermore, the Ordovician part contains sandstone, quartzites, and claystone. Soils derived from different parent materials react differently to erosion, absorbency and production of biomass: the presence of pebbles still causes an increase in runoff and therefore improved safeguard from desertification (Figure4). The influence of each class for each sub-indicator constructs SQI that was weighted based the influence on desertification process. More than 50% of the area is marked by less sensitive soils. A strip which crosses this entity in the center of the forest area is marked by moderately sensitive soils. These landscape conditions encourage sensitivity to land degradation. Calculating the vegetation quality index, on basis of the previous parameters reveal that the 60 % of the vegetation cover is very weak and sensitive to desertification (Figure5). The good vegetation index class which may resist desertification is represented olive plots. The Hmeda park have an average of a precipitation of 283mm/a and the PET is inferior to 1300 mm/an. So, the climatic quality index is inferior to 0,217. That’s why all the field have a weak climatic index. Figure 6 show the distribution of ESA’s. It is clear that most of the Hemeda park is moderately sensitive to desertification (60 %) and the very sensitive area is located in the east.

 

Through the geographical evaluation of the park, in order to qualify the different biotic (plant and soil) and abiotic (climate) components, it can be concluded that the El Hmeda peri-urban park is a natural space whose distribution of natural resources is not very equitable throughout the park, which leads to rethink landscape development through conservation and remediation planning. In this respect, a landscape analysis is essential to meet the requirements of a functional and sustainable development. 

 

3.2.  LANDSCAPE ANALYSIS

 

3.2.1.  PHYSICAL ANALYSIS

 

The physical analysis is based on the description during field visits and the use of digital media such as Google Earth, Google maps and QGIS 1.18. The park is accessible from the Mahdia-Ksour Essef road via Rojich on the north side or on the west side by the Salakta-Ksour Essef road. It is surrounded by three types of landscapes: an urban landscape constituting the center of the city of Ksour Essef, a peri-urban landscape formed by the extensions of the city and a wider agrarian landscape formed by olive groves. The slope in the park to be redeveloped is very specific which gives it a unique charm following the variation of the slopes, the division of the land into three terraces and rugged terrain. A longitudinal plot shown in Figure 7 shows that the park represents a variation in altitude between 27 m and 58 m. While the transverse plot of the same figure indicates a variation between 32 m and 61 m.