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Ecologische monitoring natuurinrichtingsproject Lombardsijde en OW-plan Oostende : t1 situatie - 2010: eindrapport 30/04/2011

Sarah Vanden Eede (UGent) and Magda Vincx (UGent)
(2011)
Author
Organization
Abstract
During the last decade, climate change has become a much debated topic. An increase in storms and rising sea levels are particularly problematic for low lying countries like Belgium. To protect our intensively used coastline against short-term (e.g. storm-induced erosion) and long-term issues (e.g. structural erosion and relative sea-level rise), we need more protective measures and regular maintenance of coastal defense infrastructures. The traditional (hard) engineering response has been to mitigate and where possible prevent erosion by coastal structures such as seawalls, groins and breakwaters. A growing necessity for sustainable development of coastal environment has led to the present interest in nourishment techniques. This soft engineering approach is now widely regarded as an environmentally acceptable method of beach and dune protection and restoration (Hamm et al., 2002). However, every anthropogenic influence has an impact on the ecosystem. The scientific evaluation of ecological effects of such an influence, like nourishment, can only be performed by comparing the status of the environment before (t0 situation) and after (t1, t2 … situation) the influence has taken place. The present study (t1 – 2010) focuses on the effects of ecological beach nourishment (Lombardsijde) and natural beach nourishment caused by structural harbor operations (Ostend-East). The beach of Lombardsijde, situated at the eastern side of the eastern palisade of Nieuwpoort, was nourished from March until September 2009. In contrast, Ostend has an active harbor which needs maintenance. A large amount of structural harbor works are being executed, leading to a deeper and wider shipping lane. These works (including some beach nourishments) will lead to an elevated sand transport. Since the eastern jetty of Ostend has been elongated, Ostend-East beach could evolve into a sand trap. This process can be regarded as the natural equivalent of beach nourishment. The soft substrates of both beaches and their control sites have been extensively monitored previous to the nourishment (Speybroeck et al., 2003; Welvaert, 2005; Van Ginderdeuren et al., 2007; Vanden Eede et al., 2008) and during the nourishment (only Lombardsijde: Vanden Eede et al., 2010). Each monitoring phase comprises a thorough study of the macrobenthos (organisms larger than 1 mm inhabiting the seafloor) and the physical-chemical environment. Phase 3 (2006) and 4 (2008) of the t0 studies and the 2009 study contained enough relevant information to define the initial state of the current sites of interest. The impact of beach nourishment on the intertidal and subtidal coastal ecosystems has been researched in the past (Speybroeck et al., 2004). On the short term, a negative influence is to be expected such as mortality of benthos due to the sand deposition. Most macrobenthic organisms however, have planktonic or pelagic larvae and the adult populations are always situated nearby. An estimated period of 1 to 2 years is enough to renew most of the macrobenthic communities. Complete renewal takes around 4 to 5 years because long living 8 organisms like Bivalvia and Echinodermata can’t reproduce successfully every year. If the environmental circumstances changed too drastic, renewal can even fail to occur. Especially changes in the median grain size and the beach profile have profound consequences. The current study showed notable changes on the beach of Lombardsijde between 2006 and 2010. Most changes occur during and directly following the nourishment with a clearly visible peak value for abundance, density and biomass in Autumn 2010. Unlike previous years, we found significant differences between the intertidal median grain size of Lombardsijde and its control site in 2010. The beach profile of Lombardsijde was altered in such a way that it still resembles the beach profile of Nieuwpoort-Bad almost perfectly. No other distinct negative trends for the macrobenthos were found but we did show (again) that Nieuwpoort-bad is a better reference site for Lombardsijde than Koksijde-Oostduinkerke. We restarted the monitoring of Ostend-East early 2010. The area and circumstances resemble those of Baai van Heist, the only Flemish beach reserve. Since its evolution was never monitored, we might gain insights into the past and present succession mechanisms by monitoring Ostend-East. The 2010 study showed biotic and abiotic changes on the beach of Ostend-East. The median grain size has been increasing since 2004 and the 2010 values of Ostend-East are significantly different from the control site. The beach profile of Ostend-East is much more leveled off in the high intertidal zone than the beach profile of Bredene Beach, probably due to erosion processes. For abundance, density and biomass, we distinguish the same clearly visible peak values in Autumn 2010 as in Lombardsijde and its control site. Ostend-East remains a heavily impacted beach so we will never be able to select an ideal control site. Wenduine and Bredene Beach are beaches that resemble Ostend-East’s natural alternative in an equally effective way. Bredene Beach was selected as future control site for practical reasons.
Keywords
zandsuppletie, ecologische monitoring, macrobenthos, Noordzee

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Citation

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Chicago
Vanden Eede, Sarah, and Magda Vincx. 2011. “Ecologische Monitoring Natuurinrichtingsproject Lombardsijde En OW-plan Oostende : T1 Situatie - 2010: Eindrapport 30/04/2011”. Gent: Universiteit Gent. Vakgroep Biologie. Sectie Mariene Biologie.
APA
Vanden Eede, S., & Vincx, M. (2011). Ecologische monitoring natuurinrichtingsproject Lombardsijde en OW-plan Oostende : t1 situatie - 2010: eindrapport 30/04/2011. Gent: Universiteit Gent. Vakgroep Biologie. Sectie Mariene Biologie.
Vancouver
1.
Vanden Eede S, Vincx M. Ecologische monitoring natuurinrichtingsproject Lombardsijde en OW-plan Oostende : t1 situatie - 2010: eindrapport 30/04/2011. Gent: Universiteit Gent. Vakgroep Biologie. Sectie Mariene Biologie; 2011.
MLA
Vanden Eede, Sarah, and Magda Vincx. “Ecologische Monitoring Natuurinrichtingsproject Lombardsijde En OW-plan Oostende : T1 Situatie - 2010: Eindrapport 30/04/2011.” 2011 : n. pag. Print.
@misc{2122720,
  abstract     = {During the last decade, climate change has become a much debated topic. An increase in storms and rising sea levels are particularly problematic for low lying countries like Belgium. To protect our intensively used coastline against short-term (e.g. storm-induced erosion) and long-term issues (e.g. structural erosion and relative sea-level rise), we need more protective measures and regular maintenance of coastal defense infrastructures. The traditional (hard) engineering response has been to mitigate and where possible prevent  erosion by coastal structures such as seawalls, groins and breakwaters. A growing  necessity for sustainable development of coastal environment has led to the present interest in nourishment techniques. This soft engineering approach is now widely regarded as an environmentally acceptable method of beach and dune protection and restoration (Hamm et al., 2002). However, every anthropogenic influence has an impact on the ecosystem. The scientific evaluation of ecological effects of such an influence, like nourishment, can only be performed by comparing the status of the environment before (t0 situation) and after (t1, t2 {\textellipsis} situation) the influence has taken place. The present study (t1 -- 2010) focuses on the effects of ecological beach nourishment (Lombardsijde) and natural beach nourishment caused by structural harbor operations (Ostend-East). The beach of Lombardsijde, situated at the eastern side of the eastern palisade of Nieuwpoort, was nourished from March until September 2009. In contrast, Ostend has an active harbor which needs maintenance. A large amount of structural harbor works are being executed, leading to a deeper and wider shipping lane. These works (including some beach nourishments) will lead to an elevated sand transport. Since the eastern jetty of Ostend has been elongated, Ostend-East beach could evolve into a sand trap. This process can be regarded as the natural equivalent of beach nourishment. The soft substrates of both beaches and their control sites have been extensively monitored previous to the nourishment (Speybroeck et al., 2003; Welvaert, 2005; Van Ginderdeuren et al., 2007; Vanden Eede et al., 2008) and during the nourishment (only Lombardsijde: Vanden Eede et al., 2010). Each monitoring phase comprises a thorough study of the macrobenthos (organisms larger than 1 mm inhabiting the seafloor) and the physical-chemical environment. Phase 3 (2006) and 4 (2008) of the t0 studies and the 2009 study contained enough relevant information to define the initial state of the current sites of interest. The impact of beach nourishment on the intertidal and subtidal coastal ecosystems has been researched in the past (Speybroeck et al., 2004). On the short term, a negative influence is to be expected such as mortality of benthos due to the sand deposition. Most macrobenthic organisms however, have planktonic or pelagic larvae and the adult populations are always situated nearby. An estimated period of 1 to 2 years is enough to renew most of the macrobenthic communities. Complete renewal takes around 4 to 5 years because long living 8 organisms like Bivalvia and Echinodermata can{\textquoteright}t reproduce successfully every year. If the environmental circumstances changed too drastic, renewal can even fail to occur. Especially changes in the median grain size and the beach profile have profound consequences. The current study showed notable changes on the beach of Lombardsijde between 2006 and 2010. Most changes occur during and directly following the nourishment with a clearly visible peak value for abundance, density and biomass in Autumn 2010. Unlike previous years, we found significant differences between the intertidal median grain size of Lombardsijde and its control site in 2010. The beach profile of Lombardsijde was altered in such a way that it still resembles the beach profile of Nieuwpoort-Bad almost perfectly. No other distinct negative trends for the macrobenthos were found but we did show (again) that Nieuwpoort-bad is a better reference site for Lombardsijde than Koksijde-Oostduinkerke. We restarted the monitoring of Ostend-East early 2010. The area and circumstances resemble those of Baai van Heist, the only Flemish beach reserve. Since its evolution was never monitored, we might gain insights into the past and present succession mechanisms by monitoring Ostend-East. The 2010 study showed biotic and abiotic changes on the beach of Ostend-East. The median grain size has been increasing since 2004 and the 2010 values of Ostend-East are significantly different from the control site. The beach profile of Ostend-East is much more leveled off in the high intertidal zone than the beach profile of Bredene Beach, probably due to erosion processes. For abundance, density and biomass, we distinguish the same clearly visible peak values in Autumn 2010 as in Lombardsijde  and its control site. Ostend-East remains a heavily impacted beach so we will never be able to select an ideal control site. Wenduine and Bredene Beach are beaches that resemble Ostend-East{\textquoteright}s natural alternative in an equally effective way. Bredene Beach was selected as future control site for practical reasons.},
  author       = {Vanden Eede, Sarah and Vincx, Magda},
  keyword      = {zandsuppletie,ecologische monitoring,macrobenthos,Noordzee},
  language     = {dut},
  pages        = {91},
  publisher    = {Universiteit Gent. Vakgroep Biologie. Sectie Mariene Biologie},
  title        = {Ecologische monitoring natuurinrichtingsproject Lombardsijde en OW-plan Oostende : t1 situatie - 2010: eindrapport 30/04/2011},
  year         = {2011},
}