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Expanding Urban and Industrial Development in Tropical Seascapes Necessitates Green Engineering and Spatial Planning Thinking Nathan J. Waltham* and Marcus Sheaves Centre for Tropical Water and Aquatic Ecosystem Research (TropWATER), Estuary and Coastal Wetland Ecosystems Research Group, James Cook University, Queensland 4811, Australia challenged with balancing requests for development approval against the need to achieve ecosystem conservation and protection.1 In 2003, Anastas and Zimmerman2 provided 12 principals fundamental in ecological sustainable development termed “green engineering”. This concept centers on combining environmental science with engineering design principals. While green engineering has been embraced in terrestrial landscapes, access to scientific data in coastal settings is less available. In the few cases, the scientific model examined has been focused on enhancing the community assemblage associated with the new structure, to more closely mimic adjacent natural habitats. In brief, these studies attached additional structure or re-engineering rock and concrete seawalls to include water retaining features, shading and crevices along otherwise featureless or smooth engineering surfaces. The results are encouraging;3 revealing that these small, inexpensive, design changes provide additional microhabitat complex for the colonization of marine organisms. More research is necessary on other coastal features, including port developments and offshore oil platforms, residential canal estates, marinas, pontoons, jetties and bridge crossings. By examining all coastal engineering features, the benefits of green engineering opportunities could then be fully he coastal zone functions as an interconnected habitat known, providing data to inform coastal policy and planning complex that provides critical nursery and feeding services frameworks. for the health and longevity of fisheries production. Protection Another point is that management decisions need to be of this habitat complex is always preferred for biodiversity cognizant of broader ecosystem processes and benefits (over the protection and conservation.1 The World Wildlife Fund recently scale of meters to 100km’s).4 Presently, the mix of land uses and (2014) finalized the “Living Planet Report” (http://wwf.panda. structures are approved under legislation and planning frameorg/about_our_earth/all_publications/living_planet_report/), works that are often inappropriate in achieving seascape and outlined that the collateral damage of human population benefits. This mismatch is based on the fact that tropical coastal growth and development, in addition to climate change, settings exist as a mosaic of hard engineering structures continues to threaten the utility of freshwater and coastal interspersed with soft shoreline areas of sand, mud and wetland wetlands as critical habitats (Figure 1). These threats are most vegetation. This is because development is considered on a caseapparent in the tropics (N 23.4378°, S 23.4378°) where by-case basis. For modern day coastal areas to function as a biodiversity is greatest, but also where most of the population productive ecosystem,1 new developments need to demonstrate that broader benefits are satisfied. growth and development is anticipated over the next few The dredging of coastal estuaries and inlets is included in this decades. In reaction to these conclusions, we advocate that message. While dredging maintains deep water access for (safe) protection of tropical coastal ecosystems under a business-asnavigation, this activity, combined with the construction of usual approach is impracticable. Resilience and protection of coastal seawalls, effectively channelizes rivers, which alters coastal services necessitates targeted scientific research on the coastal hydrology and hydraulic processes. This change not only full range of created habitats. In addition, all new development has water quality and erosion implications, but it massively limits approvals need eco-friendly engineering designs. Climate fish access to shallow habitat nursery and settlement grounds. change and rising sea level need to be also considered as part Climate change also needs to be factored; even under small of marine spatial planning initiatives. This more inclusive amounts of sea level rise, extensive inundation of low lying approach would enhance the resilience of tropical coastal coasts in many places will continue to challenge managers. In systems leading to more robust ecology that is better able to accommodate expected future landscape scenarios. The concept of ecological sustainable development has Received: December 17, 2014 emerged over the past four decades to assist managers Published: February 20, 2015
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© 2015 American Chemical Society
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DOI: 10.1021/acs.est.5b00661 Environ. Sci. Technol. 2015, 49, 2598−2599
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Environmental Science & Technology
Figure 1. Mangrove recruitment clings to a rock seawall engineered for shoreline protection in a residential canal estate in tropical northern Australia.
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many areas sea level rise will be too rapid to allow the natural lateral retreat of coastal environments, and human population and infrastructure will be exposed to damage and substantial repair costs (e.g., clean up of New Orleans following Hurricane Katerina was $96 to 125 billion (U.S. dollars); http:// useconomy.about.com/od/grossdomesticproduct/f/katrina_ damage.htm). An important unplanned consequence of coastal development is that the climate adaptation option of allowing the coastline to retreat is precluded because of the hard edges and residential buildings that immediately line the water edge.1 The customary response is more hard engineering. This approach is likely to lead to spiralling costs for government and society in the future. The NOAA national climate assessment on coastal impacts, adaptation and vulnerabilities5 recently postulated that protection of coastal assets and human lives will only become expensive as changing climate becomes more severe ($50 to 76 billion (U.S. dollars) with Florida contributing to the highest proportion because of premium prices for real estate with waterfrontage). Protection of natural wetland habitats and associated connectivity is still the preferred option for biodiversity and conservation outcomes in coastal seascapes. However, expansions to urban centers and industrial development will continue, and therefore must avoid irrevocably damaging natural ecosystem values and services. Any management decision needs to achieve the dual benefit of engineering and conservation outcomes that are also cognizant of wider seascape processes and function. This is best achieved by engaging with coastal developers early during the design phase, to ensure eco-friendly designs are included.
AUTHOR INFORMATION
Corresponding Author
*Phone: + 61 7 4781 4191; fax: + 61 7 4781 5589; e-mail:
[email protected]. Notes
The authors declare no competing financial interests
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ACKNOWLEDGMENTS This study was funded by College of Marine and Environmental Sciences, James Cook University, Australia, awarded to N.J.W. We thank Dr. A. Smith for valuable discussions on this topic.
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REFERENCES
(1) Waltham, N. J.; Connolly, R. M. Artificial urban lakes: built for humans, home for fish. Ecol. Eng. 2013, 60, 414−420 DOI: 10.1016/ j.ecoleng.2013.09.035. (2) Anastas, P. T.; Zimmerman, J. B. Design through the 12 Principles of Green Engineering. Environ. Sci. Technol. 2003, 37, 94A−101A. (3) Browne, M. A.; Chapman, M. G. Ecologically informed engineering reduces loss of intertidal biodiversity on artificial shorelines. Environ. Sci. Technol. 2011, 45, 8204−8207 DOI: 10.1021/es201924b. (4) Foley, M. M.; Halpern, B. S.; Micheli, F.; Armsby, M. H.; Caldwell, M. R.; Crain, C. M.; Prahler, E.; Rohr, N.; Sivas, D.; Beck, M. W.; Carr, M. H.; Crowder, L. B.; Emmett Duffy, J.; Hacker, S. D.; McLeod, K. L.; Palumbi, S. R.; Peterson, C. H.; Regan, H. M.; Ruckelshaus, M. H.; Sandifer, P. A.; Steneck, R. S. Guiding ecological principles for marine spatial planning. Mar. Polym. 2010, 34, 955−966 DOI: 10.1016/ j.marpol.2010.02.001. (5) Burkett, V. R.; Davidson, M. A. Coastal Impacts, Adaptation and vulnerability: A technical input to the 2012 National Climate Assessment. In Cooperative Report to the 2013 National Climate Assessment, 2012; p 150.
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