New publication finds positive relationships between biodiversity and green infrastructure in coastal Georgia


In a new study in Conservation Biology, researchers from UGA’s Institute for Resilient Infrastructure Systems, the UGA Skidaway Institute of Oceanography, and East Carolina University explore the relationship between infrastructure development and coastal biodiversity to predict changes in biodiversity under different infrastructure scenarios. 

Natural or “green” infrastructure uses natural processes as a foundation for built components to meet engineering objectives. Natural infrastructure (NI) projects along coasts can include the construction and maintenance of living shorelines as well as the conservation and/or restoration of salt marshes, dunes and reefs. NI methods can provide protections similar to traditional “gray” infrastructure, but preserve natural functions and provide environmentally-friendly co-benefits. 

This paper evaluates how the use of NI instead of traditional infrastructure can benefit long-term biodiversity. The authors analyzed the current proportions of gray and green shoreline infrastructure projects for shoreline protection, and compared different development scenarios to explore the magnitude of natural infrastructure projects that could help reverse the negative biodiversity impacts of past shoreline modification.

The study area, determined through an analysis of over 68,000 50-meter coastline segments across Southeast Georgia, mainly consisted of marshes and gray infrastructure. Using data from 2006-2021, the team created a model to show the predicted location of future shoreline modification and biodiversity changes for this area from the year 2018 to predict all the way out to 2102.

The analysis showed clearly that biodiversity losses in coastal ecosystems can be mitigated by the use of natural infrastructure instead of traditional gray infrastructure. 

Key findings:

  • For all ecosystems, shoreline segments were more likely to be modified if an adjacent shoreline segment was modified.
  • The proportion of modified shoreline increased rapidly from 2006 to 2018 and was projected to continue this trend. From 2006 to 2102, the researchers expected the total amount of modified shoreline in Georgia to increase from 5.9% to 46.7%.
  • The impact of modification on biodiversity was dependent on the infrastructure approaches in new shoreline modifications. Currently, NI coastline modifications in Georgia can be approximated to 0%, as the field is still largely unknown and still being researched. When the researchers assumed this would remain true and that 100% of shoreline modifications would consist of gray infrastructure, biodiversity metrics were predicted to reduce by nearly 10% by 2102. Alternatively, if all new modifications were NI, biodiversity was predicted to increase by over 10% instead. For no net impact on biodiversity, nearly half of all future modifications would need to be NI.

The researchers took these approximations and created a “gradual adoption” plan for NI, predicting that the proportion of NI would increase by 6% every 6-year timestep. This forecast also resulted in a near-zero net impact to biodiversity by 2102 with the predicted modifications.

These results are extremely promising for the field of NI, but present a challenge to adopt the relatively new practices at a faster rate. “The adoption of NI is a powerful tool in mitigating biodiversity losses because many studies have found NI to have greater biodiversity than the natural counterpart,” the paper states. “[The] current amount of armoring and slower rate of change mean a much greater proportion of modification would need to be NI to fully mitigate biodiversity losses.”

The authors do note that increased biodiversity isn’t automatically a good thing– while their quantification of biodiversity consists of metrics like species richness, which indicates how many species are present in an ecosystem, this means even invasive species count towards positive biodiversity. The paper also concludes with a warning that these analyses are based on current data, and sea level rise due to climate change will continue to impact shoreline modifications and biodiversity in ways that are much harder to predict. 

More optimistically, the authors also note that NI technology has room to grow and could have even more positive effects on ecosystems in the future. In the final paragraphs of the paper, the researchers reassert that their data indicates the extremely positive benefits of NI for coastal modifications, and hope for the future of coastal biodiversity as our knowledge and practices surrounding NI grow. 

Find the full paper here. The author team for this publication includes Dan Coleman, Rachel Gittman, Craig Landry, James Byers, Clark Alexander, Paul Coughlin and Brock Woodson. Special thanks were also noted for Mark Risse, J. Scott Pippin and Kevin Samples.