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iForest -Biogeosciences and Forestry
IntroductionUrbanization is a major driver of land use change and is extensively studied in land use literature, especially in disciplines like landscape ecology and watershed science. Some research focused on certain land use types (Atmis et al. 2007, Shiliang et al. 2014, while others tried to identify their impacts on biodiversity, forests and water (Du et al. 2012, Zapata & Robledano 2014. Impacts on society and natural resources have been frequently emphasized in these studies. Urbanization and associated sprawl cause changes in society and environment and therefore interact with broader issues like climate and water resources.Water is becoming a critical natural resource for Turkey with its fast urbanization trend (Serengil et al. 2012). The increasing population in big cities causes constantly increasing demand of water. New water resources have been identified and pipeline projects have been developed and implemented in the last 20 years. Melen and Istranca projects are examples of expensive long-range, trans-basin projects (ISKI 2013) supposed to meet the water demand of Istanbul for the next 10-15 years. However, threats that may break down this optimistic prevision include: deterioration of reservoirs, increasing per capita water use, variability in precipitation, and increase in evapotranspiration rates due to gradual long-term changes in temperature and precipitation conditions.Forest cover in Turkey has been increasing in the last five decades due to afforestation efforts and abandonment of farmlands in the countryside (NIR Turkey 2013). This increase has hydrological consequences as forests can significantly influence flows and conditions in a watershed (Serengil et al. 2011). Given that groundwater potential of Istanbul is low, the share of surface water resources is at 98% (ISKI 2013). This causes water supply to be strongly dependent on annual precipitation and the prevailing land use. In years of low precipitation, there is always a possibility of gap between supply and demand (deficit) during late summer months.Though not supported by solid scientific evidence, two major problems have often been identified by local authorities towards the sustainable management of water resources of the region, i.e., climate change and land use conversion in watersheds.Climate change is today's most remarkable threat towards the sustainability of natural resources (Delgado et al. 2013). Expected and (partly) realized changes in temperature and precipitation (Morrison et al. 2002, Tripathi et al. 2006, Ribalaygua et al. 2013, Quirmbach et al. 2012, Kyselý et al. 2012 as well as the response of ecosystems to projected changes in climatic parameters and atmospheric composition, have been studied thoroughly (Karnosky 2003, Senatore et al. 2012, Yang et al. 2012, Dibike et al. 2012. According to these studies, changes in precipitation or temperature or both would have consequences on evapotranspiration conditions and the water budget. As reported by Nan et al. (2011), tempera...
