Rachel Gittman September 8, 2016 Living shorelines: Are we designing functional, sustainable, and resilient coasts? Rachel Gittman September 8, 2016

Our coastlines are diverse, ranging from sand beaches to rocky cliffs on the open coast and expansive tidal marshes and mangroves on our sheltered coasts. Although coastal ecosystems represent only 4% of the earth’s land, they are considered some of the most valuable in terms of ecosystem goods and services.

Habitat Degradation & Loss Seagrass Losses >30% > 40% decline of North American salt marshes Gedan and Silliman 2009 Oyster Losses – 65-85% Waycott et al. 2009 Despite how valuable these habitats are, more than a quarter to nearly one half of our vegetated coastal habitats have been degraded our lost completely and out shellfish and coral reefs have seen even greater declines. Many factors have contributed to these declines, but coastal development s considered one of the primary drivers of habitat loss. 35% of mangroves Valiela et al. 2001 Beck et al. 2011

Shoreline Hardening When coastal properties and infrastructure are located on a coastline that is experiencing erosion, we typically resort to hardening the shoreline. We have been hardening the shoreline for centuries, with hardening dating back to the Greeks and Romans in the Adriatic, Ionian, and Agean seas. China and the Netherlands were also building coastal defense structures such as breakwaters as early as 175 B.C. Shoreline hardening has increased dramatically in the last century with the explosion of human population and coastal development. Shoreline hardening includes any kind of artificial, permanent or semi-permanient structure placed on the shoreline to prevent erosion. Despite the long history of shoreline hardening, a global estimate of how much shoreline has been hardened is not available. 14 % of the coastline of the continental United States is hardened Gittman et al. 2015. Frontiers in Ecology and the Environment

Do hardened shorelines provide functional habitat? Seawalls/Bulkheads Riprap revetments Breakwaters

Biodiversity and Abundance Gittman et al. 2016. BioScience

What are the alternatives? Living shorelines “A living shoreline incorporates vegetation or other ‘soft’ elements alone or in combination with some type of harder shoreline structure (e.g.  oyster reefs or rock sills) for added stability. Living shorelines maintain continuity of the natural land - water continuum and reduce erosion while providing habitat value and enhancing coastal resiliency.  (NOAA 2015). Nearly every state agency, National Geographic, The Nature Conservancy, NOAA, EPA have articles and resources related to Living shorelines, but few studies have documented their ability to sustain ecosystem services.

Do living shorelines provide better habitat than hardened shorelines? Marsh and Sill Gittman et al. 2016 Ecological Applications Marsh Bulkhead

Are we creating sustainable & resilient shorelines? NOAA 2011

Hurricane Impacts Hurricane Irene caused some significant damage to back-barrier shorelines on Bogue Banks and even more so on the back-barrier side of the Outer Banks. This is a picture of one of my bulkhead sites I was sampling last summer in PKS pre-and post-Irene.

Acknowledgements Coauthors John Bruno Carolyn Currin Joel Fodrie Jon Grabowski Danielle Keller Isabelle Neylan Pete Peterson Michael Piehler Alyssa Popowich Steven Scyphers Carter Smith Email: r.gittman@neu.edu Twitter: @GittmanR Lab Webpage: http://www.northeastern.edu/grabowskilab/ Personal Webpage: http://www.northeastern.edu/gittman/