Present state and evolution trends of biodiversity in the Black Sea: decline and restoration

Abstract

Abstract The biological diversity, including the marine one, and its advanced and continuous decline, respectively, range among priority issues at planetary level, y compris the Black Sea, nowadays. As to the Black Sea and its biodiversity, among the other concerns on present ecological disequilibrium, pollution, living resources, the problem consists of its five times larger watershed than the sea surface itself, totalizing about 350 km3 of freshwater, originating in the hydrographic basins of the Danube, Dneper, Dnester and Don, each year. The six Black Sea coastal states Bulgaria, Georgia, Romania, Russian Federation and Turkey themselves affect marine biodiversity directly through their land-based pollution sources. This review reveals the present state and evolution trends of Black Sea macrophytobenthos, zoobenthos, phytoplankton and related blooms, zooplankton, ichtyofauna and cetaceans, with some examples of changes occurring in the Romanian coastal and marine ecosystem during the last seven decades. The main conclusions highlight that the Black Sea ecosystem is different from that documented in the former reference periods, a slight improvement and rehabilitation tendency of the ecosystem since 1995, the considerable improvement of the pelagic ecosystem especially due to weakening of anthropic pressure. But it is still out of balance by its biodiversity and fish stocks due to eutrophication, overfishing and alien species invasion. The long lasting processes of ecosystem restoration, of qualitative improvement of environmental factors and of fishery resources depend on the efficiency of conservation, protection and management measures to be undertaken together by Danube riparian countries and Black Sea coastal states. There is still a strong need for continuing regional co-operation in the fields of monitoring, research and legislation, by developing scientifically sound data bases and communication networks, for decision makers and end-users.

Keywords

• Key words: Black Sea, biodiversity, changes, decline, restoration

References

1. Besiktepe, S., Unluata, U., Bologa, A.S. (eds.) (1999) Environmental Degradation of the Black Sea: Challenges and Remedies. NATO Science Series, 2 Environm. Security-56, Kluwer Acad. Publ., Dordrecht, Boston, London, 393 pp.
2. Black Sea Transboundary Diagnostic Avalysis (1997) GEF BSEP, PCU, Istanbul, Turkey, 142 pp.
3. Black Sea Commission (2008) State of the Black Sea (2001-2007), Istanbul, Turkey.
4. Bologa, A.S. (2001a) Recent changes in the Black Sea ecosystem. IOI Ocean Yearbook, The University of Chicago Press, Chicago and London, 15: 463-474
5. Bologa, A.S. (2001b) Destruction of marine biodiversity – A case study of the Black Sea. In: Oceans in the New Millennium: Challenges and Opportunities for the Islands. (eds., G.R. South, et al.) Proceed., IOI-PIM XXVII, Suva, Fiji, Ed.DaDa, Constanta, 249-254.
6. Bologa, A.S. (2011) Present environmental problems of the Black Sea. In: The Black Sea Dynamics, Ecology and Conservation. (eds., A.L Ryann, N.J. Perkins) Nova Science Publ., Inc., New York, USA: 265-274.
7. Bologa, A.S., Bodeanu, N., Petranu, A., Tiganus, V., Zaitsev Y.P. (1995) Major modifications of the Black Sea benthic and planktonic biota in the last three decades. In: Les mers tributaires de Mediterranée. F. Briand (éd.), Bull. Inst. Oceanogr., no. special 15, CIESM Science Series no. 1: 85:110
8. Dumont, H.J. (Ed.) (1999) Black Sea Red Data Book. UN GEF-UNDP, 413 pp. Global Environmental Facility (1992) Environmental Management and Protection of the Black Sea. Program Co-ordinating Meeting, Constanta, Romania, 22-23 May.

9. GEF Black Sea Environmental Programme – Black Sea Biological Diversity, National Reports: Romania (1997), Bulgaria (1988), Georgia (1998), Turkey (1998), Ukraine (1998).
10. Milchakova, N.A. (2011) Marine Plants of the Black Sea. An Illustrated Field Guide. Sevastopol, DigitPrint, 144 pp.
11. Milchakova, N.A., Vilkova, O. (2011) Population-based approach to the assessing of the state of the Black Sea, Cystoseira as an indicator of environment. In: 3rd Biannual BS Sci. Conf. and UP-GRADE BS-SCENE Project Joint Conf., Abstracts, Odessa, Ukraine, 1-4 November: 214-215.
12. National Institute for Marine Research and Development “Grigore Antipa” (2009, 2010, 2011) Report on the state of marine and coastal environment (in Romanian: http://www.rmri.ro).
13. Sava, D. (2006) Algele macrofite de la litoralul romanesc al Marii Negre. Ed.Ex Ponto, Ovidius University Press, Constanta, 147 pp. (in Romanian)
14. Sava, D., Bologa, A.S. (2010) The Romanian Black Sea macroalgae under current water quality of coastal waters. Rapp.Comm. Int.mer Medit. 39: 736.
15. Sorokin, Y.I. (2002) The Black Sea. Ecology and Oceanography. Backhuis Publ., Leiden, the Netherlands, 875 pp.
16. Yunev, O., Shulman, G., Yuneva, T., Moncheva, S. (2008) Long-term changes of ecological quality rating (Q-value) of the Black Sea pelagic ecosystem. In: 2nd Biannual and Black Sea Scene EC project joint conference on climate change in the Black Sea - hypothesis, observations, trends, scenarios and mitigation strategy for the ecosystem, 6-9 October, Sofia, Bulgaria.
17. Zaitsev, Y.P, Mamaev, V. (1997) Marine Biological Diversity in the Black Sea, a Study of Change and Decline. GEF BSEP, UN Publ., New York, 208 pp.
18. Zaitsev, Y.P., Ozturk, B. (2001) Exotic Species in the Aegean, Marmara, Black, Azov and Caspian Seas. Turkish Marine Research Foundation, Istanbul, Turkey, 267 pp.