Ekosistem servisleri değerinin mekânsal planlama ile ilişkilendirilmesi
Integration of ecosystem services value into spatial planning
Yazar: NÜKET İPEK ÇETİN
Danışman: PROF. DR. AZİME TEZER
İstanbul Teknik Üniversitesi / Lisansüstü Eğitim Enstitüsü / Şehir ve Bölge Planlama Ana Bilim Dalı / Şehir ve Bölge Planlama Bilim Dalı
Derece: Doktora, 2023
Konu: Şehircilik ve Bölge Planlama = Urban and Regional Planning
Dizin: Ekolojik ekonomi = Ecological economics ; Ekolojik planlama = Ecological planning ; Kent planlama = Urban planning ; Çevresel değerleme = Environmental evaluation ; Çevresel sürdürülebilirlik = Sustainable environment ; İçme suyu havzası = Drinking water basin

Özet:
Ekosistem servisleri (ES), insan yaşamının devamlılığı için ekosistemlerden temin edilen ürün, süreç ve faydalar bütünü olarak tanımlanmaktadır. Ekosistemler sundukları kaynak sağlayıcı (tedarik), düzenleyici, destekleyici ve kültürel ES'ler ile yaşam döngüsüne direkt ve dolaylı faydalar sağlamakta; insan refahı için önemli değerler üretmektedir. Ekosistemlerin ekolojik, ekonomik veya sosyo-kültürel fayda boyutlarına atıfta bulunan bu değerlerin bir kısmı içme suyu, gıda, kereste, odun dışı ürünlerin temini gibi ES'lerle doğrudan piyasa ekonomilerinde yer almakta veya farklı ekonomik sektörler için hammadde olmalarına bağlı olarak "parasal" niteliğe sahiptir. Buna karşın karbon döngüsü, biyolojik çeşitlilik, su arıtma, sel/taşkın kontrolü, biyolojik kontrol, rekreasyon gibi ES'ler ise piyasa ekonomilerinde doğrudan yer almamasına rağmen, yaşam kalitesi ve ekolojik döngülerdeki dolaylı katkıyla insan refahı için "parasal olmayan değerler" üretmektedir. ES'lerin parasal ve parasal olmayan değerlerinin toplamı, doğal sermayenin insan refahındaki önem derecesini ve fayda büyüklüğünü ortaya koymaktadır.
Temelde ES yaklaşımı, insan-doğa ilişkisini sadece etkiler üzerinden değerlendirmek yerine, yaşamın devamlılığı için gerekli ekosistem malları, hizmetleri ve faydalarının sürdürülebilirliği için doğanın üretim kapasitesinin korunmasına odaklanmaktadır. Bu nedenle son yıllarda sürdürülebilir kalkınmayı desteklemek amacıyla mekânsal planlama, karar verme ve politika geliştirme süreçlerinde ES yaklaşımına dayalı pratiklerin önemi ve gerekliliği gündeme taşınmaktadır. Küresel düzeyde son 50 yılda insan kaynaklı faaliyetlerin neden olduğu ekosistem değişimleri ve kayıplarının ES'lerin %60'ında bozulmalara veya geri döndürülemez düzeyde kullanımlara sebep olması (MEA, 2005); son 30 yılda kentsel alanların iki katına çıkmasına bağlı olarak karasal ekosistemlerdeki %23'lük verimlilik düşüşü, doğal ekosistemlerin %47 düzeyinde azalışı ile flora ve fauna türlerinin yaklaşık %25'nin yok olma tehdidi altında olması (IPBES, 2019), arazi kullanım kararları ve alan yönetimi politikalarında daha stratejik ve rasyonel karar verme mekanizmalarının gerekliliğine işaret etmektedir. Bunun için mekânsal planlamada daha kapsamlı, etkili ve uygulanabilir bir ekolojik anlayışın geliştirilerek planlama kararlarının olumlu/olumsuz etkilerinin ES performansına dayalı bir bakış açısıyla ele alınması ve ES'lerin koruma-kullanma dengesini destekleyecek çözümlerin ve stratejilerin geliştirilmesi gerekmektedir.
ES'lerde parasal değer tahminleri mekânsal karar vericiler ve uygulayıcılar için tam olarak bu ihtiyaca cevap vermek üzere, kıt kaynaklar arasında daha bilinçli ve daha verimli ödünleşmelere imkân tanımakta ve ES'lerin somut göstergelerle insan hayatındaki önemini, gerekliliğini ve değiş-tokuş edebilirliğini ortaya koymaktır. Fakat mevcut mekânsal planlama uygulamalarında, doğal sermaye ve ES'ler çok yönlü analizlerle değerlendirmemekte; ekosistemlerin ürettiği çeşitli ES değerleri göz ardı edilerek ekosistemler basit, tek yönlü, kısa vadeli mekânsal yatırımlara ve arazi kullanımlarına dönüştürülmektedir (Bateman ve diğ., 2013). Halbuki ES'lerde parasal değer tespitleri, piyasa araçlarının yönlendirdiği mekânsal planlama kararlarına karşılık doğal sermayenin yarışabilir ya da karşı durabilir bir nitelik kazanmasında kullanılabilecek bir araçtır. Bu nedenle ES'lerin farklı antropojenik faaliyetlere ne kadar katkıda bulunduğu, ES'lerle insan refahı için ne kadar fayda/değer elde edildiği ve ES üretimini sağlayan hassas ve kritik ekosistemleri koruma/geliştirme değerinin ne olduğuna ilişkin değerlendirmeler, mekânsal karar destek mekanizmalarında ekolojik perspektifin güçlendirilmesine ve rasyonel mekânsal kararların geliştirilmesine katkı sağlamaktadır.
Bu noktada tez araştırması, ES'lerde değer tahmini konusuna odaklanarak; ES'lerin parasal değerinin mekânsal planlama ve karar alma sürecine nasıl entegre edilebileceğine dair çerçevenin geliştirilmesini amaçlamaktadır. Türkiye'de ulusal ve bölgesel ölçekli birkaç mekânsal planlama uygulamasıyla birlikte yasal çerçeve kazanmaya başlayan ES konusu, biyofiziksel analizler temelinde ES haritalama ve modellemelerine odaklanırken; ES'lerde değer tahminleri, doğal sermaye ve ekosistem muhasebesi, ekolojik ekonominin kazanımları gibi boyutlar yeterli düzeyde ele almamaktadır. Halbuki küresel deneyimler, planlama paydaşlarının ES'lerin önem derecesini somut göstergelerle idrak edebilmesi için, mekânsal planlama sürecine ES'lerin ekonomik boyutunun entegrasyonun gerekliliğine işaret etmektedir. 
Bu nedenle tez kapsamında parasal ES değer tahmini konusu mekânsal planlama perspektifinden ele alınarak; ES'lerde parasal değer tahminlerinin mekânsal planlamaya katkısı ve mekânsal planlama sürecinin hangi aşamalarında parasal değer tahminlerinden faydalanılabileceği tartışılmaktadır. Ayrıca planlama sürecinin herhangi bir aşamasında yürütülecek parasal değer tahminlerinin nasıl geliştirilebileceği ve uygulanabileceğini tanımlayan "parasal ES değer tahmini metodolojisi" aktarılmaktadır. Bu metodoloji, İstanbul'un en önemli içme-suyu kaynaklarından biri olan Ömerli Havzası'nda örnek olarak uygulanarak; havzanın seçilen dört ES'sinde (gıda üretimi, su üretimi, karbon tutma ve rekreasyon) yere özgü parasal değer tahminleriyle birlikte havzanın toplulaştırılmış parasal ES değeri resmedilmektedir. Ayrıca havzanın mevcut mekânsal planlama hiyerarşisi ve planlama araçları, parasal ES değer tahminleri kapsamında irdelenerek değer tahminlerinin planlama sürecindeki etkinliği değerlendirilmektedir. Sonuçta mekânsal planlama ve karar verme sürecine parasal ES değer tahminlerinin dahil edilmesi ve etkinleştirilmesini destekleyecek yeni yapılandırmalar ve yasal araçlara ilişkin öneriler geliştirilmektedir. Böylelikle mekânsal planlama kararlarının doğal sermaye üzerinde yarattığı etkilerin gerçekçi tespiti ile karar vericilerin ekosistemlerin çok yönlü faydalarına ilişkin somut göstergelerle duyarlılık kazanmasının sağlanacağı ve sürdürülebilir planlama kararlarının geliştirilmesinin destekleneceği düşünülmektedir. Çalışmanın bu yönüyle Türkiye'deki mekânsal planlama süreci için yeni bir yaklaşım sunacağı düşünülmektedir.

Abstract:
Ecosystem services (ESs) are defined as all products, processes, and benefits provided by ecosystems. Ecosystems provide direct and indirect benefits to life through provisioning, regulating, supporting, and cultural ESs, thereby producing diverse values for human well-being. Some of these values, referring to the ecological, economic, or socio-cultural benefits derived from ecosystems- such as timber, wood, non-timber forest products, food production, and drinking water supply- are directly involved in market economies or serving as pivotal raw materials for various economic sectors, and they are easily quantified in "monetary" terms. In contrast, ESs like carbon sequestration, biodiversity, water purification, flood control, biological control, primary production, and recreation are not directly involved in market economies. Despite lacking immediate economic metrics, these non-market oriented ESs contribute indirectly to human welfare by enhancing the quality of life and ecological processes, thereby generating "non-monetary values". The aggregation of monetary and non-monetary values of ESs reveals the significance of natural capital and represents the magnitude of their contributions to human welfare.
ESs approach is centered on preserving the productive capacity of nature to ensure the sustainability of ecosystem goods, services, and benefits instead of evaluating the human-nature relations based solely on impacts. Therefore, in recent years, there has been a growing recognition of the necessity of ES-based practices within the scientific agenda aiming to facilitate more effective and practical spatial decision-making and policy development to support sustainable development. On the global scale, ecosystem changes and losses caused by anthropogenic activities over the last 50 years have led to the degradation or irreversible use of 60% of ESs (MEA, 2005). Moreover, the rapid expansion of urban areas in the last three decades has contributed to a 23% decline in productivity in terrestrial ecosystems, a 47% decline in total natural ecosystems, and nearly 25% of flora and fauna species threatened with extinction (IPBES, 2019). All these figures point to the urgency for more strategic and rational decision-making mechanisms in land-use planning and land management. Hence, it is essential to develop a more comprehensive ecological understanding of spatial planning, incorporating ES assessments to discern the positive and negative impacts of planning decisions. Therefore, this approach is crucial in developing plausible solutions and strategies to provide the balance between the protection and the utilization of ESs.
Monetary valuation of ESs responds exactly to this gap of spatial decision makers and planning practitioners, enabling more informed and efficient trade-offs between scarce natural resources, and demonstrating the significance, necessity, and exchangeability of ESs in human life with tangible indicators. However, in current spatial planning practices, ecosystems are directly transformed into simple, unidirectional, and short-term spatial investments or land-uses without multidimensional assessments of ESs. Therefore, various ESs values enhanced from ecosystems are mostly ignored in spatial planning process. At this point, monetary valuation of ESs is a useful tool to safeguard natural capital, enabling it to either compete with or counterbalance spatial planning decisions driven by market instruments. Therefore, the assessment of how much ESs contribute to different anthropogenic activities, how much benefit/value of ESs is obtained for human welfare, and what is the value of protecting/enhancing vulnerable and critical ecosystems for the sustainable production of ESs contribute to strengthening the ecological approach in spatial decision support mechanisms and developing rational spatial decisions. 
Numerous studies indicate that spatial planning actors recognize the significance of ES-based knowledge in describing the human-nature relations through measurable indicators in policy development and spatial decision-making mechanisms. Nonetheless, this knowledge is not effectively integrated into planning practices because, 
- the existing experts of planning actors does not have sufficient experience and capacity, 
- the interest and awareness of planning stakeholders are quite insufficient,
- the lack of economic, social, and ecological data required for ES assessments and difficulties in conducting site-specific ES analyses, and 
- the ES approach does not yet have a legal basis in the spatial planning process.
Furthermore, the prevailing convictions among planning actors that "the ES approach does not make an innovative contribution to traditional environmental management" are perceived as one of the major constraints to advancing conventional decision-making and spatial planning processes through innovative approaches (Spyra et al., 2019). Despite these reasons, ESs valuation and defining the critical roles of ESs in human welfare with the expressions of traditional market economies can bring many discussions into the planning agenda which planning actors have not considered before. Additionally, ESs valuation can also obtain to concretize non-market oriented ESs in units that can be measured with economic parameters. Thus, it is believed that the public interest and added value to be obtained through the sustainability of ESs can be presented to planning actors with more transparent and concrete indicators. 
On the other hand, it can be asserted that the experiences of ESs approach and monetary ESs valuation practices are quite limited in Türkiye (Başak et al., 2022). The adoption of the ES topic in Türkiye has been subject of research since 2010s and it is being disseminated under the leadership of academic initiatives and gradually integrated into spatial planning practices through collaborative scientific studies with central and local government institutions. While a few national and regional scale planning practices have played a significant role in establishing a legal basis for ESs approach in Türkiye; these examples predominantly concentrate on biophysical assessment of ESs as mapping and modelling applications, and they have not taken into account ESs valuation, natural capital and ecosystem accounting or the obtainment of ecological economics. 
Therefore, the focal point of the thesis centers on the valuation of ESs to develop a framework for the instrumentalization of monetary ES value by discussing on how the monetary value of ESs can be integrated into the spatial planning process. Hence, this research addresses the monetary valuation of ESs from a spatial planning perspective and discusses the contribution of monetary valuation of ESs to spatial planning by determining in which stages of spatial planning process monetary valuation of ESs can be utilized. Moreover, this research also presents a "methodology for monetary valuation of ESs" that describes the roadmap on how monetary valuation of any ESs can be developed and applied at any stages of spatial planning process to support the development of sustainable land-use planning and land management decisions as well as their effective implementation. 
To illustrate this methodology, the Ömerli Watershed, which is one of the most important drinking water supply of Istanbul, is employed as an example to present the aggregated monetary ES value of the watershed, including site-specific monetary valuation of four selected ESs as food production, water supply, carbon storage and recreation. These ESs are prioritized by the stakeholders of water management and they figure out the ecological, economic and socio-cultural values of the watershed for metropolitan population. 
Each ES assessment is conducted by selecting appropriate quantification and monetary valuation methods based on the ES indicators which are defined according to the available and accessible spatial and non-spatial data. In this context, the food production is assessed with the quantity of agricultural and husbandry products along with the economic value generated through the buying and selling of these products in the market. The water supply is generated by collecting the runoff from precipitation in the dam reservoir and utilizing this amount of water to the demand of the population in Istanbul. Thus, precipitation-runoff relations are analyzed based on the LULC and meteorological data in the watershed and the revenue from the selling of the amount produced water by water company (ISKI) is considered as the monetary value of the water supply services. Carbon storage, which is considered as regulating service in the watershed, is evaluated by the carbon sequestration capacity of LULC and its role in climate and air quality regulation. Herein, the amount of carbon storage is determined by the InVEST model and the monetary value is estimated by applying unit value transferred method based on social cost of carbon in the literature. And finally, the cultural value of the watershed is explored by estimating the monetary value of recreational activities through the travel-cost method based on the recreational visits in the watershed. 
Based on LULC data in 2014-2016 period, the research findings indicate that in the Ömerli Watershed: 
- the monetary value of food production has more than 227 million TL/year with an annual average of 621,02 tons of vegetable production; 16.489,44 tons of cereal production and other vegetable products, 426,44 tons of fruit and spice production, 373.923 livestock and 26.791,80 tons of animal food,
- the quantity of water supply was 225,3hm3; 222,7hm3 and 233,5hm3 in2014-2015 and 2016, respectively by amounting to 11,7 billion TL (2014), 16,0 billion TL (2015), 17,7 billion TL (2016) and the magnitude of ESs benefit to the citizens' quality of life corresponding to an average annual monetary value of water supply is 15,02 billion TL,
- carbon storage has a monetary value of 1,0 billion TL (2014), 1,3 billion TL (2015), 1,4 billion TL (2016) based on the annual carbon capacity of 11,670,904.29 tons,
- regarding recreation service, recreational visits in the watershed require an average annual cost of 307.52 TL per person, the consumer surplus of recreational visits per person is more than 8 times the costs and generate an annual recreational value of 2,458.87 TL/person.
These results reveal that in the 2014-2016 period, the four ESs in the Ömerli Watershed collectively added a yearly total of 24,1 billion TL with 2018 prices to the social welfare and quality of life in Istanbul, which equals to 2,09% of Istanbul's GDP in 2018. Among the four assessed ESs, water supply services hold the highest value, while the carbon storage contributes nearly double the value compared to the food production and recreation ESs. 
The changes in the aggregated monetary value of ESs estimated based on literature indicate that the urban developments over the past 30 years have led to significant declines in the overall ES value in the watershed. Comparing the 1990 and the 2018 Corine LULC data, there has been a 10,2% reduction in forest and semi-natural areas, a 34,1% loss in agricultural areas, and a 343,2% increase in built-up areas. This shift has resulted in an 11,25% decline in the total ES value in the watershed, and agricultural ESs experienced the most significant loss in value. At the same time, the expansion of built-up areas led to an increasing ES value associated with urban green areas throughout this 30-year period.
The outcomes of monetary valuation in the Ömerli Watershed have also produced significant inputs to spatial planning practices. In this context, agricultural areas in Çekmeköy, Şile, Tuzla, Sancaktepe, Gebze and Pendik districts play a crucial role in food production. Simultaneously, the densely forested areas in the northern part of the watershed produce high-quality drinking water due the high-water retention and infiltration capacities. Certain areas such as Çekmeköy-Koçullu, Kömürlü, and Esenceli Neighborhoods; Şile-Kervansaray, Bıçkıdere, Oruçoğlu Neighborhoods; and Gebze-Mudarlı, Ovacık, Cumaköy Neighborhoods, emerge as vital for carbon storage service. Additionally, military areas in Çekmeköy, forest areas in Kartal (Aydos, Kuzudere, and Şalgamlı), Maltepe (Büyükbakkalköy), Sultanbeyli (Teferrüç Tepe Forest) and Kurna, Kurtdoğmuş, Yenişehir Neighborhoods in Pendik, along with specific agricultural zones in Çekmeköy (Paşaköy) and Tuzla (Tepeören) can be defined as vulnerable areas for carbon storage in the catchment. Moreover, the catchment exhibits a high potential for providing recreational services to the metropolitan area.
In this research, the existing spatial planning hierarchy and planning tools in the Ömerli Watershed are also examined in terms of monetary valuation to evaluate its effectiveness in the spatial planning process. The results show that spatial planning tools which govern/direct the LULC of the watershed do not cover adequate integration of the ESs approach and monetary valuation practices. It is estimated that the total monetary value of the watershed has declined by 11,25%, particularly between 1990-2018 due to the changes in LULC resulting from urbanization dynamics. Furthermore, based on the spatial decisions outlined in the 1/5000 scale master plans, which determine the future LULC of the watershed, the total monetary ES value may decrease by 4,95% compared to LULC in 2012.
All these findings underscore the necessity of revising the dominant planning methodologies and procedural frameworks in the spatial planning process via adaptation of ES-based practices integrating monetary valuation so as to gain acceptance among planning actors. Thus, it will be possible to develop concrete solutions in the spatial planning process which can be listed as: 
- Raising awareness of planning actors on the positive/negative impacts of spatial policies and spatial decisions on ecosystems,
- Embodying human-nature interaction through natural capital and ecosystem accounting assessments in the planning areas, 
- Development of spatial policies and planning actions taking into account vulnerable and critical ESs in the planning area, as well as identification of implementation priorities,
- Including the costs of losses and gains in ESs in implementation programs and budgeting realistic calculations for spatial decisions,
- Development of incentive and subsidy programs to support positive practices in spatial decisions, as well as deterrent punishment mechanisms and compensation for negative practices, 
- Resolution of legal disputes and quantification of the public interest in spatial decisions.
For this purpose, this thesis recommends several issues for developing new planning methodologies and legal instruments to support the inclusion and activation of monetary ES valuation in spatial planning and decision-making processes. In this way, it is believed that the development of sustainable spatial planning decisions will be supported by concretizing the multidimensional benefits of natural capital in the analysis, synthesis, planning/design, decision-making, and monitoring/controlling stages of the planning process and by realistic determination of the impacts of spatial decisions on natural capital. In this respect, this research is believed to provide an innovative approach to the spatial planning process in Türkiye.