This goal assesses the amount of protection provided by marine and coastal habitats against flooding and erosion to coastal areas that people value, both inhabited (homes and other structures) and uninhabited (parks, special places, etc.).
A score of 100 indicates habitats that provide coastal protection are intact or have been restored to their reference conditions.
Habitat-based goals (Storage, Coastal Protection, and Biodiversity) should be considered together during the data gathering process because the same data underly these goals.
STEP 1: Identify relevant habitats You will first determine the habitats in your study that protect marine coastlines. In global assessments, coral, mangroves, saltmarshes, seagrasses, and sea ice were included.
We generally do not include an assessment of the protection afforded by man-made structures, such as jetties and seawalls. These structures cannot be preserved without maintenance and often have negative side effects (e.g., alter sedimentation rates causing erosion in new locations), thus they do not constitute long-term sustainable service and are mostly seen as a pressure. It gets tricky when structures are built to help reduce coastal erosion–they are still manmade and therefore not a natural benefit that the ocean provides. But if data allow, it might be possible to include tradeoff effects: maybe in areas where natural habitats are degraded and man-made structures have been built to reduce erosion, we could reduce the pressure that would otherwise be applied.
STEP 2: Determine contribution of each habitat
The relative contribution of each habitat to total coastal protection is based on the area of the habitat and the relative protection it provides. For the Global Assessment, the protective ability of each habitat was based on relative weights obtained from the Natural Capital Project. Depending on the habitats you include, you will need to find additional weights.
STEP 3: Determine habitat condition
The score for this ultimately depends on the health of each habitat. A score of 100 means all habitats that contribute to carbon removal are still intact or have been restored and they can function to their full potential.
The reference point for assessing the condition of habitats will likely be temporal, meaning you will compare the current area of these habitats to some area in the past, and thus historic data are needed. Reference points could also be set by with a proportion increase (or decrease) of known conditions.
Review the section on Biodiversity sub-goal: Habitats for guidance on habitat extent and condition.
STEP 4: Other considerations
OHI+ assessments for Coastal Protection may also incorporate additional variables at the local scale. Physical properties may be available, allowing for more a detailed understanding of the protective ability, and likelihood of exposure for different portions of the coastline. Models may also incorporate estimates of the vulnerability of coastline regions to inundation, due to potential financial loss as well as costs to human life, structures, or habitats.
|Assessment||Developing the Model||Setting the Reference Point||Other Considerations|
|Global 2012||The habitats included mangroves, coral reefs, seagrasses, salt marshes, and sea ice. The status was calculated as a function of the amount or condition of marine habitat relative to reference states and the ranked protective ability of each habitat type.||The reference point compares the current extent and condition to their condition in the early 1980s.||This focused on the EEZ scale and assumed that all coastal areas have equal value and equal vulnerability.|
|Global 2013 - 2015||The goal model was the same as in Global 2012.||The reference was the same as Global 2012.||This approach followed the Global 2012 approach.|
|Brazil 2014||The 12 nmi boundary was used for each habitat type for mangroves, seagrasses, coral reefs, and salt marshes. Only costal portions were used for mangroves. The total reported extent divided by the coastal area of each state was used for seagrasses. For coral reefs we calculated the extent per coastal waters of each state using maps of coral reef distribution. The salt marsh extents for some states were from national statistics.||The reference condition was the mean of the predicted values for 1985-1987 using regional estimations for coral reefs. The ‘current’ condition or health was the mean of the predicted values for 2008-2010.||Same goal model as Global 2012, while using local data.|
|U.S. West Coast 2014||Salt marshes, seagrasses, and sand dunes were included.||Temporal reference points were set for each habitat. For salt marshes, the percentage of pre-industrialized habitat coverage. For sand dunes, the habitat extent between the 1950s and 1960s.||Same as Global 2012, with more ambitious reference points for target habitat coverage.|
|Israel 2014||See Global 2012. Sand dune was the habitat of interest.||Reliable, comprehensive satellite photos from 1970 enabled an evaluation of the habitat extent of the sand dunes as its reference point.||Other important habitats, such as rocky reefs and the rocky intertidal flats, could not be included due to lack of data on current and/or past spatial extent and condition.|
|Ecuador - Gulf of Guayaquil 2015||The status is calculated in the same manner as in the Global assessment. Mangroves in the coastal strip (1 Km offshore and inland) were considered the main source of coastal protection, and was used for calculations.||The reference condition was the existing mangrove coverage in the protective area for 1991.||Values are measured in units of area (km2).|
|China 2015||The approach is the same as in global assessments. Four habitats are measured: mangroves, seagrasses, salt marshes, and coral reef.||A temporal reference point for each habitat is set to its condition in 1980’s.||These four habitats provide the most coastal protection and have available data. Not all habitat exist in all provinces and time-series data of extent is poor for some. Time-series data on the condition of each habitat is not obtainable. However, rough estimate of relative change in coverage areas since the 1980’s was found in literature.|