Mapping of Posidonia Oceanica (L.) Delile Meadows Using Geographic Information Systems: a Case Study in Ufakdere - Kaş (Mediterranean Sea)
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International Journal of Environment and Geoinformatics 3 (3), 92-97 (2016) Mapping of Posidonia oceanica (L.) Delile Meadows Using Geographic Information Systems: A case study in Ufakdere - Kaş (Mediterranean Sea) Volkan Demir 1,*, Emine Ş. Okudan Aslan 2, Sibel Zeki 1, İ. Noyan Yılmaz 1, Cem Gazioğlu 1 1 Institute of Marine Sciences and Management, İstanbul University, Müşküle Sokak No: 1, 34116, FATIH, ISTANBUL-TR 2 Faculty of Aquatic Sciences and Fisheries, Akdeniz University, Dumlupınar Bulvarı, 07059, ANTALYA-TR Corresponding author* Tel: +90 212 4400000/26050 Received 17 November 2016 E-mail: [email protected] Accepted 22 December 2016 Abstract Posidonia oceanica (Linnaeus) Delile 1813 is an endemic and the most widespread seagrass species of the Mediterranean Sea. Seagrass meadows are one of the most productive ecosystems on Earth, providing habitat to numerous organisms. Therefore, mapping of seagrass meadows is of crucial importance for conservation and coastal management purposes. Here we present an integrated geographic information system approach with SCUBA diving, providing a cost effective method to monitor seagrass beds at shallow coastal habitats. In this case study P. oceanica meadows were mapped in Ufakdere region of Kaş (Antalya) coastal area between April – September 2015. A total of 25000 m2 are were screened to create seagrass coverage maps. Results indicate that P. oceanica meadows cover 21200 m2 and we estimated that 520 m2 of this area is highly damaged. This integrated approach provided one of the most detailed small-scale Posidonia mapping in Turkey and this time and cost effective methodology can be applied to any seagrass meadow with great ease to increase our knowledge on this important habitat. Keywords: Posidonia oceanica, GIS, Mapping, Scientific diving Introduction and acts as a barrier against the coastal erosion, severe wave movements and current; it stabilizes Posidonia oceanica L. (Delile) (Pasqualini et al., the coastal line. P. oceanica, is sensitive to 1998), is an endemic sea grass species of the changes in water quality. Rhizomes can adsorb Mediterrenean Sea. It is abundant in Turkey's radioactive materials, synthetic chemicals and or Aegean and Mediterranean coast all throughout heavy metals so that as a result of this ability, the infra-littoral zone. P. oceanica distributions they can be used as biological indicators for can be observed at temperature range from 11° monitoring the quality of coastal waters to 29°C and at a depth from 0 to 40 m (Cirik et (Pergent-Martini, 1998). al., 2006). It is known to be sensitive to increase in salinity and can exist at a salinity range from Sea grass meadows, which have an important 33 to 40% (Fernández-Torquemada and role in coastal systems (Hemminga and Duarte, Sánchez-Lizaso, 2005). P. oceanica meadows 2000), is under threat due to pressure from the play an important role in global carbon cycle by increasing population (Short and Echeveria, enriching the oxygen content in coastal waters 1996). through photosynthesis utilising the daylight (Bay, 1984). Its leaves’ serve as a natural filter, P. oceanica, is exposed to direct physical effect settle coarse grains of sand and catch solid by illegal trawling (Ardizzone and Pelusi, 1984), materials in the water column. Thus, they and indirectly by the sedimentation resulting provide water clarification by reducing the from harbor and breakwater construction, boat turbidity. P. oceanica, fixes the sandy sea anchorage or soil erosion. Furthermore, potential bottom with the help of its horizontal rhizomes effects of the global climate change such as sea 92 V. Demir et al. / IJEGEO 3 (3), 92-97 (2016) water temperature increases (Mayot et al., 2005), b) rather than information on the biology and carbon dioxide level increases, reduction of pH ecology of meadows. The most significant levels and acidification, impacts the contribution on P. oceanica distribution and P. photosynthesis of meadows, hence affects oceanica meadows as a habitat is the reproduction and development. proceedings of the “First National Workshop on Posidonia oceanica on the coasts of Turkey” P. oceanica meadows are declining at alarming (Aktan and Aysel, 2013). rate due to pollution, climate change, alien species invasion and human activities The aim of the present study was to map P. (Montefalcone, 2009, Telesca et al., 2015). oceanica meadows using an integrated Therefore, P. oceanica is listed in Red List of geographic information systems approach in Threatened Species by the International Union order to understand current human impacts and for Conservation of Nature (IUCN). Moreover, establish a baseline study and methodology to it is under protection by Barcelona Convention, monitor the future changes. Bern Convention, European Union Habitat Directive and many other countries’ national Materials and Methods legislations. Study Area GIS, together with remote sensing and mapping, is crucial for scientist and decision makers in The study was carried out in a shallow sublittoral understanding and management of marine zone in Ufakdere Cove, located in the environment (Kapetsky and Aguilar-Manjarrez, southwestern Mediterranean coast of Turkey 2007). This competence is essential, especially (Figure 1). Study area is part of the Kas-Kekova in biodiversity studies, where research needs to Specially Protected Area (SPA) which is one of be replicated at regular intervals and whose the most biologically rich marine ecosystems in characteristics are to be monitored over time. Turkey. Nowadays, in most of the modeling studies, GIS integration is required) which is a powerful and Substrate consists of sandy bottom between effective tool used by several multi-disciplinary depths of 20 and 30 m and mix substrate of sand scientists to produce rapid, economic, reliable and rocky bottom at shallower depths (0 - 18 m) and accurate results (Sertel and Şeker, 2013). in inner parts of Ufakdere Cove. There is a high flow freshwater input, which is known as "Altug Although seagrass studies are abundant all over Cave", at a depth of 11 m at the eastern end of the world, studies are scarce in coasts of Turkey. Coban Cape. Majority of the meadows are found Majority of reported work focuses on species between 18 and 30 m. Inner part of the cove ends assemblages with in the meadows (Okuş et al., with a pebble beach, with a muddy sandy 2006a-b, Okuş, et al., 2007; Meriç et al., 2016a- substrate due to a creek discharging to the bay. Fig.1. Study area 93 V. Demir et al. / IJEGEO 3 (3), 92-97 (2016) Data collection and processing marking procedure, scientific divers continuously performed dives in transects, and Small buoys attached to lead weights were used recorded the meadows from the same distance to as georeferenced points to validate satellite the bottom by using a 2 m long string and images and coordinates for in-situ observations. weight, attached under the camera system and In total 16 markers were submerged and fixed to barely touching the bottom while filming. All the bottom at pre-determined intervals starting gathered information on the distribution and from 2 m depth. GPS coordinates were recorded coverage of P. oceanica meadows were at surface for each marker. Following the integrated in ArcGIS platform (Figure 2). Fig. 2. Markers and study plan Results The results showed that satellite images provided high accuracy information up to 20 The distribution of P. oceanica from the shore meters’ depth. The water temperature was 27 °C (~ 1 m) to 26 m is observed in the Ufakdere area. throughout the study area where the average The Posidonia distribution below the rocky annual sea water temperature is 21 °C. The shore region is transformed into a massive, dominant stress on the P. oceanica meadows in single piece meadow, with severely damaged the region was anchoring. The red line in Figure clusters particularly in the mid-coastal area, 3 indicates the area of heavy anchor damage. where the anchoring activity is intense. There is Particularly, the damage due to the heavy use of regional sedimentation on the leaves at the the region by daily boat tours possess a shallow area, in close proximity to the mouth of significant threat. Damage concentrating in the the creek, and in summer, when the temperatures middle block of facies is threatening to separate are extremely hot, a recession in the facies to the one piece facies into two. deeper parts is noticed, indicating that water temperature negatively affects the facies in the Significant loss of seagrass beds were observed shallow region. particularly at shallow section and anchorage area. As a summary our observations revealed in The data obtained from the dives and the approximately 21200 m2 of meadow area, of distribution data extracted from the satellite which an estimated 520 m2 is highly damaged images were superimposed on the Esri ArcGIS (Figure 3). program. The damaged area is mapped in detail. 94 V. Demir et al. / IJEGEO 3 (3), 92-97 (2016) Fig. 3. Distribution of P. oceanica in Ufakdere-Kaş (Mediterranean Sea) Discussion and Conclusion long-term studies on distribution and health status of P. oceanica meadows in the This study provides the baseline data for the Mediterranean Sea (Ardizzone et al., 2006,), distribution of P. oceanica meadows in providing valuable information man and climate Ufakdere region. Posidonia oceanica is seen induced changes in these important ecosystems. only in the Beş Adalar and the Ufakdere sites in Kaş Kekova Marine Reserve. In general, the SCUBA dives showed significant damage of the rocky bottom structure in the region and high facies by anchoring. The immediate need for sedimentation rates due to foraminifera designated and managed anchorage zones were depositions considerably limits habitat for the declared in other studies along the Aegean and development and expansion of P. oceanica Mediterranean coasts of Turkey (Okudan et al., (Yokeş, 2009). The integrated satellite 2015; Francour et al., 1999; Montefalcone et al., imaginary and in-situ observations approach 2008).