Climate Change on Cape Cod National Seashore
Changes in climate could cause problems with the biological, chemical, and hydrological processes on the Cape Cod National Seashore. Therefore, it is a major priority to monitor the Cape Cod National Seashore closely and understand how the effects of increasing temperature, storms, and sea level that are predicted to happen in the future could affect the area.
Image 9 is a photograph of Marconi Beach, which is a part of the Cape Cod National Seashore, after a destructive storm in 2010. More frequent and strong storms are predicted to happen as climate change continues to happen.
Using Remote Sensing to Monitor Climate Change
Long-term ecosystem monitoring (dating back to the 1950's) helps to keep track of any changes occurring on the Cape Cod National Seashore. Investigations into long-term trends of wildlife populations, coastal vegetation, and water quality, are just some of monitoring done on the Cape Cod National Seashore. Satellite images and aerial photographs, such as Image 10, are useful in seeing changes over time in small areas.
Image 10 is an aerial photograph of Coast Guard spit on the Cape Cod National Seashore.
Case Study: Salt Marsh Dieback
Salt marshes are an important part of the coastal ecosystem and there are many salt marshes through out the Cape Cod National Seashore. One problem with salt marshes is salt marsh dieback, which is the permanent loss of vegetation not caused by erosion, wrack kills, and tidal flow. The first notice of salt marsh dieback on the Cape Cod National Seashore was in 2002.
Image 11 shows the dieback occurring in the Gut marshes in August 2006.
Possible Causes
There are several hypotheses for salt marsh dieback. One is related to climate change. High marsh dieback always occurs on the seaward side at the lowest elevations. This suggests that the cause of high marsh dieback might be caused by sea level rise due to climate change. Field studies over the past twelve years has showed that seaward-side dieback zones experience more high tides, higher water levels, and slower drainage than healthy seaward-side high marshes. Therefore, one of the reasons for high marsh dieback may be explained by flooding due to sea level rise.
Image 13 is a series of six panchromatic aerial photographs from 1984-2005 of the Great Island-area marsh. The black line shows the edge of the salt marsh retreating from high marsh dieback. Click on the image to enlarge it.
Originally, salt marsh dieback appeared to be a sudden phenomenon. As it turns out, salt marsh dieback had been happening for decades. Aerial photographs in the early 1980's show salt marsh dieback occurring in several salt marshes on the Cape Cod National Seashore. Image 12 is an aerial infrared photograph of a salt marsh in West Dennis Beach in 1984. The blue-gray areas along the mosquito ditches are vegetation loss. The dark red areas are low marsh vegetation and pink areas are high marsh vegetation.
Image 12 is an aerial infrared photograph from 1984 of a salt marsh in West Dennis Beach, MA. The blue-grey areas are vegetation loss, the dark red areas are low marsh vegetation, and the pink areas are high marsh vegetation. Click on the image to enlarge it.
Affects from Salt Marsh Dieback
One of the biggest problems due to salt marsh dieback is erosion. Erosion leads to the widening of tidal creeks and a further reduction in marsh lands. Image 14 shows the changes over time to the Swan River in Dennis, MA due to salt marsh dieback erosion.
Image 14 is a series of aerial photographs from 1952 to 2005 of the Swan River in Dennis, MA. The white circle shows the erosion occurring over time. Click on the image to enlarge it.