The Value of Posidonia oceanica in Turkey’s Aegean


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The Value of Posidonia oceanica in Turkey’s Aegean
Esra Başak, Camille Bann, Güner Ergün, Harun Güçlüsoy
İstanbul Üniversitesi
Forestry Faculty
29 June 2011
Strengthening the system of Marine and Coastal Protected Areas of Turkey Project

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  • This case study examines the (monetary) values of seagrasses in two MCPAs in Turkey (namely Foça & Gökova SEPAs) as part of a larger valuation of the ES provided in Turkey’s network of marine/coastal PAs. The project enabling the research is “Strengthening the MCPA network in Turkey” implemented by the Turkish Min. Of Forestry & Envrmt - EPASA unit and with UNDP Turkey as implementing partner.
    The case study was chosen as part of the present conference on forest ES, their values and externalities, because similar to terrestrial biomass, the marine environment provides significant services to human well-being, often not captured in conventional markets (similar to forests in Turkey). There is increasing evidence that marine vegetation plays a crucial role in oceanic/marine carbon cycle and maintain an ecological balance both on smaller/regional and larger/global scales. In fact, often seagrasses are called “forests of the sea”.. Seagrass communities in Turkish Aegean have not been examined from their ES perspective before and are thus the subject of the present valuation attempt. The resulting values can be used for improved decision making and conservation management for Turkey’s MCPAs (ie. Being aware of their economic weight can help choose between different management options etc...)
  • For an optimum growth Posidonia needs transparent waters. For this reason, the presence of dense and large meadows is a clear sign of the quality of its waters.
    It’s endemic yet very restricted in the Med due to anthropogenic disturbances -  constitute 3% of the basin. This corresponds to a surface area of about 38,000 square kilometre. It is found at depth ranges of 5 to 50 meters.
  • Seagrasses provide a wide range of ES:
    Per square meter it is capable of producing a daily amount of up to 14 liters of oxygen as an average
    The meadows provide habitat and food for big number of fish species and invertebrates, especially larvae and young fishes.  
    They also play an important role in the processes concerning beach and dune systems. The dead leaves of Posidonia oceanica that one can find in the shores act as a natural barrier reducing the energy of the waves, minimizing erosion. 
    Nutrient cycling 
    Subsurface rhizomes and roots stabilize the plant while erect rhizomes and leaves reduce silt accumulation. They operate as coastal water filters.
    Carbon sequestration – Coastal ecosystems remove CO2 from the atmosphere via photosynthesis, return some to the atmosphere via respiration and oxidation and store the remaining carbon in two pools: living biomass (includes both aboveground and belowground vegetation) and soil organic carbon. Globally seagrass meadows account for 15% of the ocean’s total carbon storage. The ocean currently absorbs 25% of global carbon emissions.
    Due to data and time limitations, this study’s focus is only on C (sequestration & storage). And for avoiding double counting the economic returns on fisheries, the nursery function is not valued.
    Though difficult to value in monetary terms, seagrass meadows also provide other direct and indirect social and cultural values as well (ie. Cleaner seas, improved quality of life and tourism etc)
  • Marine vegetation including the Posidonia seagrasses, store C mainly in the organic soil. Over 95%–99% of total carbon stocks of seagrasses (& tidal marshes) are stored in the soils beneath them. This is different than forest ecosystems where the C stocks are usually higher in the living biomass.
  • It is possible to assess the value of the C sequestred & stored in the Posidonia meadows as these habitats store substantial amounts of carbon that can be released as carbon dioxide upon disturbance, thereby becoming a source for greenhouse gas emissions. The valuation of the C sequestration & storage relies on literature review taking into account the net C sink capacity of the plant per ha/per year (in its submerged sections – matte – as well as its living biomass).
    By using the avoided cost approach, it is possible to calculate the amount of C emissions released over time into the atmosphere if the Posidonia habitats at two studied sites were to be lost to some human driven conversion/threat.
    GIS application of field based researches on Posi. distribution for both sites were conducted previously by SAD under other MCPA management/conservation projects. We made use of their findings.
    Applied the Voluntary Carbon Market prices of C stated for TR in the Report “State of the Voluntary C Markets”. Accordingly, “In Turkey volumes grew in 2010 as a new supply of renewable energy credits – and buyers – came online. Although Turkey ratified the Kyoto Protocol, it is ineligible to generate Clean Develeopment Mechanism (CDM - quand un pays emitteur fait un projet de reduction de carbon dans un pays en developpement) or Joint Implementaion credits, and the voluntary market therefore remains its main niche until 2013, the end of the Kyoto Protocol. The vast majority of Turkish credits transacted voluntarily in 2010 were from Gold Standard wind credits (78%)
    Upperbound is based on EU Emissions Trading System.
  • The carbon sequestration rate quantifies how much carbon is added to the biomass and soil carbon pools
  • Study demonstrates that the seagrass communities in Foça & Gökova host an asset that can be articulated in monetary terms as important C sinks much like forests.
    As elsewhere in the world, Posidonia meadows face tremendous pressures. An equivalent rate of up to two football fields per hour are lost globally (roughly equal to current rates of loss of coral reefs or tropical rainforests). Main threats for the meadows in Turkey are pollution of near-shore waters, anchoring, trawling, maritime constructions, beach nourishment with sand and the elimination of the Posidonia oceanica dead leaves on the beach sand (cultural perception of “clean beach”)
    Posidonia does not only remain “unseen” physically as they’re under water but they are also unnoticed in the carbon accounting. Conventional markets fail in taking into account the wide range of ES and values provided by the Posidonia meadows in TR as elsewhere.
    Not enough studies are conducted about the Posidonia functionings (both ecologically & econ) in Turkey. Foremost the former (lacking ecological data, ie about their soil depth) limits the validity of the present valuation (need to make assumptions & generalizations). Furthermore, both in Foça & Gökova the health of the meadows is jeopardized by increasing human impacts/inputs to the marine systems studied. This requires tight control & monitoring activities in the PAs.
    EU’s Habitat Directive establishes Posidonia oceanica as a priority habitat. Turkey’s allignment to EU nature conservation policies (marine as well as terrestrial) can be seen as an opportunity for more rigourous conservation of these marine habitats. On the financial side, eventually PES schemes such as Blue Carbon schemes could be developed for the maintenance of Posidonia ES (projects such as the current UNDP-GEF can provide an infrastructure for these options). This is similar to REDD payment schemes (Reduced Emissions from Deforestation & Degradation), an instrument of global CC policy, esp. İn the tropics.
  • The Value of Posidonia oceanica in Turkey’s Aegean

    1. 1. The Value of Posidonia oceanica in Turkey’s Aegean Esra Başak, Camille Bann, Güner Ergün, Harun Güçlüsoy İstanbul Üniversitesi Forestry Faculty 29 June 2011 Türkiye’nin Deniz ve Kıyı Koruma Alanları Sisteminin Güçlendirilmesi Projesi
    2. 2. Content     Background information Range of Ecosystem Services provided by Posidonia oceanica Valuation Methodology Results & Discussions
    3. 3. Türkiye’nin Deniz ve Kıyı Koruma Alanları Sisteminin Güçlendirilmesi Projesi   Part of a larger valuation study on six MCPAs in Turkey Motivation behind the valuation of seagrasses Study Sites: Gökova SEPA Foça SEPA Background – E.S. Provision – Valuation – Results & Discussions
    4. 4. Mediterranean Seagrass (Posidonia oceanica)      A flowering plant that grows in marine, fully saline environments Among the 60 seagrass species that exist globally Seagrasses occur in all shallow coastal areas of the world (except Antarctica) Endemic to the Mediterranean Form meadows and grow in sandy or rocky sediments along the coasts
    5. 5. Mediterranean seagrass meadows “Lungs of the sea” (+/- 14 lt O2/m²/day )  Support high biomass  Fish nursery and fishing grounds  Enable protection against coastal erosion  Cycle nutrients  Reduce silt accumulation  Contribute to the production of organic carbon via the process of photosynthesis  C sequestration  Provide social and cultural values.  Background – E.S. Provision – Valuation– Results & Discussions
    6. 6. Posidonias’ metabolism
    7. 7. Healthy seagrass environment Source: Laegdsgaard 2001
    8. 8. Soil-Carbon Stocks (source: Nicholas Institute for Environmental Policy Solutions, Duke University) tCO2e per Hectare, Global Averages For Comparison: 8
    9. 9. Methodology for Valuation  Literature review on Posidonia’s C flows (sequestration) & C sink capacity (tCO2 eq/ha/yr)  Avoided Cost Method GIS Assessment of Posidonia distribution and surface occupied at study sites Application of Carbon Market Prices Lowerbound $11.2/tCO2 eq (based on Voluntarily traded av. prices for Turkey in 2010) Upperbound $20/tCO2 eq (based on EU ETS)   - - Background – E.S. Provision – Valuation – Results & Discussions
    10. 10. Seagrass Distribution in Gökova SEPA Total surface = 13 km2
    11. 11. Seagrass Distribution in Foça SEPA Total Surface = 6,7 km2
    12. 12. Avoided Carbon Emissions Value (US$11.2 / tCO2eq) Posidoni a surf ace (ha) Site Gökova C seq † (tCO2 eq/h a/yr) Soil C rele ased †** (tC O2e q/h a/yr ) 1 300 670 Total 1 970 50 † ** 5 658 954 408 218 2 916 541 1 200 282 8 575 495 609 36 448 54,4 Value US$ /yr PV (10 yrs, 10% ) US$ 792 064 Value US$ /ha /yr 70 720 4,4 Foça Total C loss per site (tC O2e q /yr) 107 168 609 Value (US$20 / tCO2eq) Value U S$ /h a/ yr Annual Value / US$ PV (10 year s, 10% ), US$ 1 414 400 10 105 276 728 960 5 208 104 2 143 360 15 313 380 1 088 1 088 Based on Duarte et al 2010 & Nicholas Institute for Environmental Policy Solutions 2010 Assuming a 10 year release period of soil carbon after habitat destruction Background – E.S. Provision – Valuation – Results & Discussions
    13. 13. Conclusions      Embedded natural capital Main threats facing Posidonia Unmanifested/unperceived values Research & monitoring needs Conservation & financing opportunities