Determination of Human Impact on Land Cover: The Case of Ankara Province
Rüya Bayar, Kerime KarabacakThe particular characteristics of populations combined with human use of technology is having an increasing impact on land cover with each passing day. These land cover changes have caused many economic and ecological problems as the use of off-purpose land becomes more widespread . Indeed, the problems caused by these changes are often irreversible. In this study, which aims to determine the human impact on land cover in the case of the province of Ankara we used the method of determining human impact index developed by Sanderson et al., and the criteria applied by SEDAC constituted the basis of the research. In this context, population density, transportation network, nighttime lights, land cover, and urban areas were re-classified and overlapped using GIS software. The spatial analysis results showed that the human impact index distribution, the 2018 CORINE land cover, and the 2006-2012-2018 land cover change data were correlated. The results also showed which type of land cover was located in the human impact area in Ankara Province. The study concluded that Ankara metropolitan areas, which expand towards the west and partly towards the south, have landforms, which have an important effect on agriculture, forests and semi-natural areas.
Arazi Örtüsü Üzerindeki Beşeri Etkinin Belirlenmesi: Ankara İli Örneği
Rüya Bayar, Kerime Karabacakİnsanoğlunun sahip olduğu nüfus özellikleri ve teknolojisi arazi örtüsü üzerindeki etkisini her geçen gün biraz daha arttırmaktadır. Bu etki ekonomik ve ekolojik pek çok problemi ortaya çıkarırken arazi örtüsü üzerinde de amaç dışı arazi kullanımını yaygınlaştırmıştır. Bu durum çoğu zaman geri dönüşü olmayan problemlerin ortaya çıkmasına neden olmuştur. Ankara İli örneğinde arazi örtüsü üzerindeki beşeri etkiyi belirlemeyi amaçlayan bu çalışmada Sanderson ve arkadaşlarının geliştirdiği beşeri etki indeksi belirleme yöntemi ve SEDAC’ın uyguladığı kriterler esas alınmıştır. Bu kapsamda nüfus yoğunluğu, ulaşım ağı, gece ışıkları, arazi örtüsü, şehir alanları özellikleri Coğrafi Bilgi Sistemleri yazılımları aracılığıyla yeniden sınıflandırılarak çakıştırılmıştır. Mekânsal analiz sonucu elde edilen beşeri etki indeksi dağılımı ile 2018 CORINE arazi örtüsü ve 2006-2012 ve 2018 yılı arazi örtüsü değişimi verileri ilişkilendirilerek Ankara İli’nde hangi tip arazi örtüsünün beşeri etki alanında yer aldığı tespit edilmiştir. Yeryüzü şekillerinin uzanışına bağlı olarak batı ve kısmen güney yönlerinde büyüme gösteren Ankara metropolünün tarım, orman ve yarı doğal alanlar üzerinde önemli bir etki oluşturduğu sonucuna varılmıştır. İlde beşeri etkinin en yüksek olduğu arazi örtüsü tipini şehirlerin çevresinde yer alan tarımsal alanlar oluştururken ikinci sırada orman ve yarı doğal alanların geldiği dikkati çekmektedir.
The tangible effects of humanity on the natural environment began with the establishment of the settled life and accelerated due to the increasing population and the technology it developed. The development of new socio-economic activity areas has led to the transformation of natural areas within the land cover to human areas, which has laid the groundwork for the emergence of various environmental and land use problems. In this respect, determination of human impacts on land cover in terms of their power and location is of great importance in order to make it easier to take measures and to ensure that land cover is protected and passed on to future generations.
One of the most important studies aimed at quantifying human impact on land cover was the human impact index prepared by Sanderson and colleagues who aimed to reveal the effects of human activities on the natural environment. Indeed, the Socioeconomic Data and Applications Center (SEDAC), which is affiliated to the National Aeronautics and Space Administration of the United States, mapped the global human impact index based on this study. Using this index, many researchers have determined the extent of human impact on the natural environment and land cover and the direction of these impacts. In this study, the primary aim is to determine the human impact on the land cover of the Province of Ankara in terms of its power and location and to demonstrate the extent to which the land cover types are affected by this pressure.
Continuously attracting large populations and expanding in area due to its being Turkey’s second largest city and the capital city of the country, Ankara province was selected as the study area. Another factor which influenced our choice of Ankara as the study area was the presence of certain human factors affecting land cover changes such as the province being located in the middle of Anatolia and having developed highways and railways connecting the east, west, north and south of the country. A further reason for our choice of Ankara is that it contains settlements that have hosted many civilizations from the past to the present.
In this study, the method of determining human impact index developed by Sanderson et al. and the criteria applied by SEDAC constituted the basis of the research. However, since Ankara is not located on the coast and since it does not have rivers which are used for transportation , the criteria of coastal belt and rivers identified by Sanderson have been ignored. However, the other six criteria were considered and scored as shown in Table 1, and spatial analysis was performed in Geographical Information Systems (GIS). In order to calculate the population density, Ankara province’s neighbourhood boundaries and TUIK (Turkish Statistics Institution) address-based population registration system data were used, and population density scoring was rearranged in accordance with the scale of the study area. NOOA “Night-time lights” images were used to determine settlement areas, and 1/250.000 scaled digital topography maps were employed for main highways and railways data. The 2018 CORINE land cover and 2006-2012-2018 CORINE land cover change data were used to determine land cover types and urban areas.
When population density, distance to major highways and railways, nighttime lights, urban areas and land cover types were reclassified and overlapped according to the specified criteria, in an area of approximately 3677km2 of the province (14% of the total acreage of the province), human impact was found to be significant, 80% in the high and very high impact group and 15% in the moderate impact group. The intensity of this effect generally decreases as we move from Ankara city center to the outskirts. The districts with the highest human impact were determined as Polatlı, Beypazarı, Elmadağ and Kalecik district centers which have a rapid population growth and urbanization rate, as well as the districts which make up the metropolitan center of Ankara.
When the CORINE land cover change in the province of Ankara between 2006-2018 is considered, an area of about 1109,96km2 is seen to have transformed into a different type of land cover. 64% of this change is in areas where Human Impact Index is medium, high and very high. While the transformation of artificial areas within the human impact area alone has an important share, the transformation from agricultural areas to artificial areas is also of such a significant amount that it cannot be neglected.
When the distribution of the human impact index areas of Ankara province over the existing land cover is examined, it can be seen that the agricultural areas within Ankara and especially around the city are the most affected and yet to be affected land type, followed by forest and semi-natural areas. In particular, the spatial expansion of the city of Ankara towards the west and partly towards the south has caused the agricultural and pasture areas to be transformed into urban areas.
