İklim değişikliğine mekansal uyumda toprak ekosistem servislerinin rolü: Nilüfer çayı havzası
The role of soil ecosystem services in spatial adaptation to climate change: Nilüfer stream basin
Yazar: MERVE YILMAZ MUTLU
Danışman: PROF. DR. AZİME TEZER
İstanbul Teknik Üniversitesi / Lisansüstü Eğitim Enstitüsü / Şehir ve Bölge Planlama Ana Bilim Dalı / Şehir Planlama Bilim Dalı
Derece: Yüksek Lisans, 2023
Konu: Şehircilik ve Bölge Planlama = Urban and Regional Planning

Özet:
Dünya üzerinde %2'lik bir alanı kaplayan kentsel alanlar, Dünya nüfusunun yarısından fazlasına ev sahipliği yapmaktadır ve bu alanlar, ormansızlaşma ve fosil yakıt kullanımını teşvik eden politikalarla iklim krizini olumsuz yönde etkilemektedir. Buna ek olarak, kentler iklim krizinin sebep olduğu kırılganlıklara karşı da her geçen gün daha duyarlı hale gelmektedir. Toprak sunduğu çeşitli ekosistem servisleri (ES) ile bu bağlamda öne çıkmakta ve sağladığı faydalarla iklim kriziyle mücadelede kentleri daha dirençli hale getirmektedir.
Karbon (C) depolama, tarım, su kaynaklarının yönetimi, doğal tehlikelerin kontrolü, ve habitat sağlama ToES'lerin (ToES) öne çıkan faydalarındandır. ToES'lerin iklim değişikliğinin olumsuz etkilerini minimize etme kabiliyetleri onları uyum ve azaltma stratejileri ve politikaları geliştirmekte önemli araçlar yapmaktadır. İklim krizine karşı kentlerin direncini arttırma yolunda ToES sağladığı faydalar ile mekânsal planlama süreçlerinde yer seçim kararlarında değerlendirilmesi gereken hassas ekolojik alanlardır.
Bu çalışmada toprak ekosistem servislerinin iklim değişikliğine uyum kapsamında mekânsal planlama karar süreçlerindeki önemi ve yeri incelenmektedir. Bu bağlamda öncelikle ekosistem servislerinin sağladığı faydalar ve toprak ekosistem servisleri tanımı, sınıflandırılması ve iklim değişikliği ile ilişkisine dair literatür ortaya koyulmaktadır. Çalışmanın bir sonraki aşamasında mekânsal planlama ve ToES ilişkisi ortaya konulmakta ve literatür taramasında ortaya çıkan bulgular Türkiye'deki mevzuat dahilinde değerlendirilmektedir.
İncelenen çalışmalar ile ToES ve iklim değişikliği ilişkisinde öne çıkan kavramların (İ-ToES) veri toplama ve analiz yöntemleri tartışılmaktadır. Sonuç olarak bu çalışmada iklim değişikliğine mekânsal uyum kapsamında planlama aracı olarak İ- ToES'e dayalı çok kriterli yer seçimi uygunluk analizi yaklaşımı sunulmaktadır. Çıkan sonuç bütünleşik ES haritasıyla çakıştırılarak bir değerlendirme yapılmaktadır. Sonuçlar, ToES tabanlı yerleşime uygunluk analizinin, mekânsal karar üretme süreçlerinde etkili bir araç olma potansiyeli taşıdığını göstermektedir. İ-ToES tabanlı yerleşime uygunluk analizi klasik yer seçimi analizlerine göre doğal yapıyı ve onların ekolojik işlevlerini korumada daha rasyonel sonuçlar üretmektedir. Nitekim bu yaklaşım ES'leri değerlendirmede daha başarılı sonuçlar üretmiştir. Bu çıkarım, çalışma alanı olarak seçilen Bursa Nilüfer Çayı Havzsası'nda yapılan örnek alan incelemesi sonucu üretilmiştir. Nilüfer Çayı Havzası, sahip olduğu doğal değerlere rağmen yaşadığı hızlı toprak kaybı ve karşı karşıya olduğu baskılar ile ToES ve mekânsal planlama ilişkisini anlamaya uygun bir araştırma alanı olarak değerlendirilmiştir. Bununla birlikte havzalar sahip oldukları toprak yapısı ve ssağladıkları faydalar ile kent planlama için önemli çalışma alanları olmaktadır.

Abstract:
Urban areas, covering a mere 2% of the Earth's surface, host more than half of the global population. However, these urban spaces, while concentrating human activity, also contribute to the exacerbation of the climate crisis through deforestation and the promotion of fossil fuel consumption. Simultaneously, they find themselves becoming more attuned to the vulnerabilities induced by this very climate crisis.
The impacts of urbanization, driven by policies that endorse deforestation and reliance on fossil fuels, ripple far beyond their physical boundaries. Not only do they amplify the ecological stressors that fuel climate change, but they also magnify the susceptibility of urban centers to the ensuing climatic vulnerabilities. This dual role of urban areas as contributors to and sufferers of the climate crisis underscores their significance in the broader environmental discourse.
Amidst these complexities, soil emerges as a pivotal player, offering a range of diverse ecosystem services (ES) that garner attention within this context. These services encompass a spectrum of benefits, encompassing carbon sequestration, water filtration, and temperature regulation, which collectively contribute to climate change mitigation and adaptation. Therefore, recognizing and harnessing the potential of soil's ecosystem services becomes a fundamental tool in the arsenal of strategies aimed at combating the climate crisis and fostering urban resilience.
Soil emerges as a critical resource for mitigating the effects of climate change. Soil ecosystem services (SoES) provide a wide range of benefits, including carbon sequestration, agricultural production, water purification, and flood control. These services, which provide benefits in various areas have the ability to minimize the negative effects of climate change, making them important tools for developing adaptation strategies and policies. However, SoES are increasingly threatened by human activities, such as land use change and pollution. Human occupation of soil increases the process of C emission into the atmosphere.
This study examines the significance and role of soil ecosystem services within the context of spatial planning decision processes for climate change adaptation. To achieve this, the critical evaluation of SoES is conducted within the framework of relevant legislation in Turkey, focusing on the selected study area, the Bursa Niliüfer River Basin.
In the case area, SoES are assessed as decision support tools. Key climate change- related SoES, such as carbon sequestration, water cycle regulation, climate regulation, and hydro-meteorological disasters, are spatially mapped within the study area. The identified SoES are evaluated for their suitability in settlement development decisions and their relationships with ecosystem service integrity, primarily through a multi- criteria analysis approach. The study also discusses the contributions of this process to climate change adaptation.
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The study aims to assess the scope of Suitability Analysis SoES based settlement planning, conducted through two distinct analyses. In the first analysis, a variety of factors including land use, soil classification, Digital Elevation Model (DEM), and slope are considered. The second analysis employs SoES indicators primarily related to climatic factors, such as soil depth, soil carbon retention capacity, soil loss, flood risk, temperature, and precipitation. The outcomes of this research demonstrate that SoES-based suitability analysis more rigorously identifies suitable areas for urban development and provides urban planners with a more comprehensive perspective, enhancing its effectiveness.
Urban planning guided by the principles of SoES integration can bolster spatial adaptation to climate change. Sustainable land-use practices, like incorporating permeable surfaces and green infrastructure, enable soils to effectively regulate water flow, minimizing flooding risks during extreme weather events. Moreover, strategic urban afforestation can enhance soil stability, preventing erosion and landslides often exacerbated by intense rainfall and increased temperature variability.
Preserving SoES aligns with urban planning efforts aimed at conserving biodiversity. Healthy soils harbor diverse microbial communities that contribute to nutrient cycling and plant health. By nurturing these soil microbial ecosystems, urban planners can create synergistic relationships between SoES and urban biodiversity, fostering a resilient and thriving urban environment.
While the integration of SoES into urban planning presents numerous benefits, challenges persist. Land scarcity, competing land-use demands, and limited public awareness about the value of SoES may hinder their effective implementation. Overcoming these challenges requires interdisciplinary collaboration among urban planners, ecologists, policymakers, and communities to develop innovative solutions and strategies.
As cities increasingly grapple with the impacts of climate change, recognizing the pivotal role of soil ecosystem services in spatial adaptation through urban planning becomes paramount. By harnessing the natural functions of soil, urban areas can fortify their resilience against climate-induced stressors. Integrating SoES into urban planning frameworks offers a holistic approach that not only mitigates climate impacts but also nurtures sustainable, biodiverse, and livable cities. As urbanization continues to shape our world, prioritizing soil ecosystem services paves the way towards a more climate-resilient future.
In this study, the importance and role of soil ecosystem services in the context of climate change adaptation within spatial planning decision processes are examined. In this context, firstly, the benefits provided by ecosystem services and the definition, classification, and their relationship with climate change of soil ecosystem services (ToES) are presented in the literature. In the next stage of the study, the relationship between spatial planning and ToES is outlined, and the findings from the literature review are evaluated within the framework of Turkish legislation.
The study discusses data collection and analysis methods for the prominent concepts in the relationship between ToES and climate change (İ-ToES) based on the examined studies. As a result, in this study, an approach to multi-criteria site suitability analysis based on İ-ToES is presented as a planning tool for climate change adaptation within the spatial context. The results are compared with an integrated ES map to provide an
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assessment. The results indicate that ToES-based site suitability analysis has the potential to be an effective tool in spatial decision-making processes. İ-ToES-based site suitability analysis produces more rational results in preserving the natural structure and their ecological functions compared to traditional site selection analyses. Indeed, this approach has yielded more successful results in assessing ecosystem services. This inference is derived from a case study conducted in the Bursa Nilüfer River Basin, the selected research area. Despite its natural values, Nilüfer River Basin is considered a suitable research area for understanding the relationship between ToES and spatial planning due to the rapid soil loss it experiences and the pressures it faces. However, basins are important areas for urban planning due to their soil structure and the benefits they provide.