Abstract—Fires is one of the main types of disturbances that shape ecosystems in the Mediterranean region. However nowadays, climate alterations towards higher temperatures result on increased levels of fire intensity, frequency and spread as well as difficulties for natural regeneration to occur. Thasos Island is one of the Greek islands that has experienced those problems. Since 1984, a series of wildfires led to the reduction of forest cover from 61.6% to almost 20%. The negative impacts were devastating in many different aspects for the island. The absence of plant cover, post-wildfire precipitation and steep slopes were the major factors that induced severe soil erosion and intense floods. That also resulted to serious economic problems to the local communities and the inability of the burnt areas to regenerate naturally. Despite the substantial amount of published work regarding Thasos wildfires, there is no information related to post-wildfire effects on factors such as soil erosion. More research related to post-fire effects should help to an overall assessment of the negative impacts of wildfires on land degradation through processes such as soil erosion and flooding. Keywords—Erosion, land degradation, Mediterranean islands, regeneration, Thasos, wildfires. I. INTRODUCTION ATURAL disturbances such as fires and floods are part of the ecosystems that help sustain their structure and functions. The impacts of fires can be positive or negative, depending on the type, intensity, and frequency of fires, as well as the effect of other factors such as grazing [1]. In some terrestrial ecosystems, wildfire is an important ecological factor that triggers evolution. Usually, frequent fires occur naturally and despite the fact that they might destroy part or the entire ecosystem, their negative effects are usually reversible. This is mainly due to the ability of the plant species to withstand intense disturbances, such as wildfires, thanks to adaptation mechanisms that they have developed. High soil temperatures and increased nutrients availability after a wildfire create favorable conditions for specific plant species to occupy the sites [2], [3]. However, when the intensity and frequency of those disturbances exceeds the ability of the ecosystems to cope and maintain levels of natural regeneration then ecosystem sustainability becomes problematic. The negative impacts of wildfires are widely known. Some of those negative impacts are microclimate George D. Ranis is a Forester, Thasos Forest Service, Thasos, Thasou, Greece (e-mail: gpd-tha@damt.gov.gr). Valasia Iakovoglou is a PhD Researcher, with Eastern Macedonia and Thrace Institute of Technology, Dept. of Forestry and Natural Environment Management, Drama, Greece (corresponding author, e-mail: viakovoglou@yahoo.com). George N. Zaimes is a Professor of Technological Applications, with Eastern Macedonia and Thrace Institute of Technology, Dept. of Forestry and Natural Environment Management, Drama, Greece (e-mail: zaimesgeorge@gmail.com). alterations, limited presence (or even absence) of flora and fauna, lack of seed bank, runoff and frequent flood events, as well as reduction of the aesthetic value of the landscape [2], [4], [5]. Nowadays, climate change towards higher temperatures favors the intensity and frequency of fires, with the Mediterranean region experiencing intense alterations. Hence, fires are considered the number one type of disturbance that usually occurs after prolonged drought periods, especially towards the end of summer [6]. The prevailing climatic conditions are the key factors that affect the initiation and spread of fires as well as the ability of those ecosystems to be restored after the disturbance event [7]. Specifically for Greece, for the last few decades frequent and intense wildfires is considered a major problem. According to official data of the Greek Forest Service for the period of 1983-2006 the number of forest fires was 38,085 and the total burnt area was 13,613,121 acres. That was the result of intense dry climate especially during summer time in relation to increased biomass accumulation that was associate with reduced agricultural activities in rural areas as well as poor forest management was main factors [8]. Thasos is a Greek island that faces those problems that are associated with wildfire, in addition to “post-fire” induced problems such as floods and soil erosion. Despite the substantial research work that has been conducted for Thasos regarding the occurrence of wildfires, there is a lack of data for post-wildfire effects on issues such as soil erosion [2], [4], [9]. In this paper emphasis will be given on the wildfires of 1985 and 1989 that are considered the most devastating wildfire events in terms of intensity, duration and total burnt including residential sites for Thasos island. Hopefully, this paper will trigger future research on short- and long-term post- wildfire effects such as soil erosion and floods. II. MATERIAL AND METHODS A. Study Area Thasos is a Greek island located at the most northern part of the Aegean Sea (40 o 34''-40 o 48'' N, 24 o 30''-24 o 46'' E). It is 16 and 5.5 nautical miles far from the harbor of Kavala and Keramoti, respectively. The size of the island is approximately 38,000 acres and its shape is almost circular. In addition, the topography is characterized by streams, valleys, and extensive lowlands along the sea coast of the island. Almost 75% of the area is covered by forests and the remaining 25% is cultivated by agricultural crops such as grapes and olive trees. The highest mountain that occupies most of the center of the island is "Ipsario" that reaches the 1,203 m height. The soils are rather shallow with parent material limestone. Rarely, there are areas with deeper soil formations that usually occur in George D. Ranis, Valasia Iakovoglou, George N. Zaimes Ecosystem Post-Wildfire Effects of Thasos Island N World Academy of Science, Engineering and Technology International Journal of Environmental and Ecological Engineering Vol:9, No:10, 2015 1282 International Scholarly and Scientific Research & Innovation 9(10) 2015 scholar.waset.org/1307-6892/10002836 International Science Index, Environmental and Ecological Engineering Vol:9, No:10, 2015 waset.org/Publication/10002836