Scholarly record
ASSESSING THE STATUS OF FISH FAUNA IN THE VELEKA RIVER THROUGH AN ADAPTED LIVING PLANET INDEX (LPI): TRENDS AND ECOLOGICAL IMPLICATIONS
Abstract
This study applies an adapted Living Planet Index (LPI) to assess long-term trends in fish populations in the Veleka River (southeastern Bulgaria) from 2010 to 2024. Based on standardized electrofishing data across seven stations, 11 native and naturalized species were analyzed using log-transformed abundance time series. The LPI declined from 1.0 in 2010 to 0.28 in 2024, indicating a 72% reduction in average fish abundance. Potamodromous species (e.g., Barbus cyclolepis, Chondrostoma vardarense) exhibited declines exceeding 80%, with some becoming locally extinct. This trend aligns with increasing summer water temperatures (+1.4 -C anomaly), diffuse agricultural pollution, and moderate hydromorphological alterations. Physico-chemical gradients revealed oligotrophic headwaters transitioning to mesotrophic and eutrophic conditions downstream, with nitrate concentrations rising from less than 0.5 to 1-3 mg/l. Linear regression showed a significant negative trend (R- = 0.758), supporting the LPI's sensitivity to cumulative stressors. These findings confirm the utility of the LPI as a biodiversity indicator at local scale and call for urgent conservation measures, including riparian restoration and nutrient load control. The study recommends integrating LPI metrics into national monitoring under the EU Water Framework Directive and Biodiversity Strategy 2030.
Publication Impact Profile
Publication details
References18
Dudgeon D, Arthington A.H, Gessner M.O, Kawabata Z, Knowler D.J., L�v�que C, Naiman R.J., Prieur-Richard A.H., Soto D., Stiassny M.L., Sullivan C.A, Freshwater biodiversity: importance, threats, status and conservation challenges. Biol Rev Camb Philos Soc. 2006 May;81(2):163-82. DOI: 10.1017/S1464793105006950.
Reid A.J., Carlson A.K., Creed I.F., Eliason E.J., Gell P.A., Johnson P.T.J., Kidd K.A., MacCormack T.J., Olden J.D., Ormerod S.J., Smol J.P., Taylor W.W., Tockner K., Vermaire J.C., Dudgeon D., Cooke S.J., Emerging threats and persistent conservation challenges for freshwater biodiversity. Biol Rev Camb Philos Soc. 2019 Jun;94(3):849-873. DOI: 10.1111/brv.12480.
Tickner D., Opperman J.J., Abell R., Acreman M., Arthington A.H., Bunn S.E.,Young L., Bending the curve of global freshwater biodiversity loss: An emergency recovery plan, BioScience, USA, vol. 70(4), 2020, pp 330�342, ISSN 0006-3568, DOI: 10.1093/biosci/biaa002.
V�r�smarty C.J., McIntyre P.B., Gessner M.O., Dudgeon D., Prusevich A., Green P., Glidden s., Bunn S.E., Sullivan C. A., Liermann C. R., Davies P.M., Global threats to human water security and river biodiversity, Nature, UK, vol. 467(7315), 2010, pp 555�561, ISSN 0028-0836, DOI: 10.1038/nature09440.
Woodward G., Perkins D.M., Brown L.E., Climate change and freshwater ecosystems: impacts across multiple levels of organization, Philosophical Transactions of the Royal Society B: Biological Sciences, UK, vol. 365(1549), 2010, pp 2093�2106, ISSN 0962-8436, DOI: 10.1098/rstb.2010.0055.
Loh J., Green R.E., Ricketts T., Lamoreux J., Jenkins M., Kapos V., Randers J, The Living Planet Index: Using species population time series to track trends in biodiversity Phil. Trans. R. Soc. B (2005) 360, 289�295 DOI: 10.1098/rstb.2004.1584.
WWF, Living Planet Report 2024 � Building a Nature-Positive Society, WWF International, Switzerland, 2024.
Deinet, S., Scott-Gatty, K., Rotton, H., Twardek, W. M., Marconi, V., McRae, L., Baumgartner, L. J., Brink, K., Claussen, J. E., Cooke, S. J., Darwall, W., Eriksson, B. K., Garcia de Leaniz, C., Hogan, Z., Royte, J., Silva, L. G. M., Thieme, M. L., Tickner, D., Waldman, J., ... Berkhuysen, A. (2020). The Living Planet Index (LPI) for migratory freshwater fish: Technical Report. World Fish Migration Foundation. https://worldfishmigrationfoundation.com/wp-content/uploads/2020/07/LPI_report_2020.pdf
Ledger, S.E.H., Loh, J., Almond, R. et al. Past, present, and future of the Living Planet Index. npj biodivers 2, 12, 2023. DOI: 10.1038/s44185-023-00017-3.
Rounsevell, M. D. A., Settele, J., Tucker, G., van Vuuren, D. P., & Young, O. R. Biodiversity and human well-being: An urgent call for integrated action (IIASA Policy Brief No. 37). Laxenburg, Austria: International Institute for Applied Systems Analysis (IIASA). 2023. https://iiasa.ac.at/sites/default/files/2023-03/ PB37_Biodiversity _WEBnew.pdf.
Simic, V., Simic, S., & Pesic, V. 2023. Ecological Sustainability of Fish Resources of Inland Waters of the Western Balkans. Freshwater Fish Stocks, Sustainable Use and Conservation, DOI: 10.1007/978-3-031-36926-1.
Alkan, A., Serdar, S., Fidan, D., & Kili�, M. B. (2013). Physico-chemical characteristics and nutrient levels of the Eastern Black Sea rivers. Turkish Journal of Fisheries and Aquatic Sciences, 13(5), 847�859. DOI: 10.4194/1303-2712-v13_5_09 https://www.trjfas.org/uploads/pdf_137.pdf
Mihov, S. 2010. Development of Fish Based Index for Assessing Ecological Status of Bulgarian Rivers. Biotechnology & Biotechnological Equipment, Special Balkan Conference Edition. Retrieved from https://scispace.com/pdf/development-of-fish-based-index-for-assessing-ecological-oacod3v3k6.pdf
Dimov, D., Georgiev, D., Goranova, C., et al. 2023. Fish diversity, status and distribution in Bulgarian Black Sea catchment rivers. Diversity, 15(9), 954. DOI: 10.3390/d15090954
Ministry of Environment and Water (MoEW), Management Plan for Protected Site BG0001007 � Veleka River, Sofia, Bulgaria, 2016.
Dikov, T., & �ivkov, M. Abundance and biomass of fishes in the Veleka River, Bulgaria. Folia Zoologica, 53(1), 2004, pp 81�86..
Trichkova T., Stefamov T., Mihov St., Vasilev M., Zivkov M., Species composition and conservation status of the ichtyofauna in the South Black Sea revers of Bulgaria. Scientific articles. Ecology 2006. Pp 327 � 338, ISBN 954-9368-16-5.
Collen B, Loh J, Whitmee S, McRae L, Amin R, Baillie JE. Monitoring change in vertebrate abundance: the living planet index. Conserv Biol. 2009 Apr;23(2):317-27. DOI: 10.1111/j.1523-1739.2008.01117.x. Epub 2008 Nov 17. PMID: 19040654.
View or Download full articleAccess options
SWS access login
Login as SWS Scientific CommitteeLogin as SWS Scientific PartnerLogin as SWS AuthorAuthors and approved SWS contributors will read and export their own linked papers after identity matching by SWS profile, email and SGEM GlobalID.
For librarian assistance: [email protected]
Purchase Instant Access
- Article can be downloaded after successful payment.
- Article may be used according to SWS library access terms.
- Article cannot be redistributed.