Many different environments make up Earth’s ecosystems. Climate change can have strong impacts on both the terrestrial and aquatic spheres. Both freshwater and marine ecosystems are likely to be affected by the ongoing changes due to global warming. Some effects on marine ecosystems include changes in sea level, changes in strength and frequency of coastal storms, water temperatures, abundance of sea ice, and changes in ocean circulation. In terms of national park conservation, certain national parks are composed of mostly aquatic environments. Therefore, increases in temperature, among other factors, can have significant impacts on the park and the wildlife that reside within it. This post will focus on two national parks, Glacier Bay National Park in Alaska, and the parks in South Florida including the Everglades. The unique changes that are likely to occur in marine ecosystems can potentially significantly alter these two environments and their inhabitants.

Glacier Bay National Park in Alaska is a picturesque, nearly pristine environment and the home of many species of wildlife. I was in awe when I first saw Glacier National Park.  The enormous glaciers were breathtaking. The eerie noise that the glaciers made when they calved made you shiver and realize firsthand the impact of global warming. I think my only comment was “wow.” Glacier Bay is in such a remote area which is only accessible by ship or plane therefore, doing research in this area is very challenging. Increased global warming, however, is melting glaciers and sea ice that encompasses the park and is relied on so heavily by animals. A particular species that has been monitored since the 1970’s is the harbor seal. Harbor seals have been documented to inhabit both terrestrial and ice habitats and more moms and pups have been found on icebergs rather than land in Glacier Bay. The long-term population surveys performed on animal species allows for researchers to observe changes in population sizes as well as other factors and how they vary with time. About ten percent of harbor seals rely on ice derived from glaciers for resting, pupping, and caring for their young. The ice likely offers protection of pups from predators.  In addition, the ice from glaciers may help serve as large breeding grounds for harbor seals.

Harbor seal pokes his head out above the icy water. Photo courtesy of sixdegreesbelowthehorizon/ Flikr Creative Commons

Throughout the years, harbor seal populations have been declining in key glacial sites where they have traditionally been found. Although harbor seal decline in Glacier Bay National Park has been observed, the true cause of the decline is unknown. Changes in harbor seal location may cause an interference with other species which compete for a similar food source. It is also interesting to note that researchers have found that harbor seal populations have remained rather stable on land. More research is needed however to best estimate the loss of harbor seal populations in Glacier Bay and the likely cause. Harbor seal monitoring also exists in other areas such as the Point Reyes National Seashore. Researchers understand that harbor seals are susceptible to changes in sea level and ocean changes which may alter shorelines. Further studies need to be undertaken to further understand the impacts on harbor seals in these systems.

Another national park that is susceptible to changes resulting from global warming is the Everglades National Park located in Southern Florida. I have visited the Everglades several times and am always amazed to see alligators and birds in their natural habitat.  It is one of the most unusual places I have ever seen. The environment of the Everglades consists of 1.5 million acres of wetlands and marshes which are the homes to many species of birds, fish, and mammals. A major concern that exists is the state of the Everglades as sea level continues to rise at an increasing rate which may affect the freshwater inlets of the park which may increase salinity. A park that is and has been valued so highly for its unique ecosystem and abundance of wildlife species may be undergoing significant changes. The National Park Service has documented this quote from former President, Harry S. Truman, whom stated this comment at the Dedication of the Everglades National Park, in 1947:

“Not often in these demanding days are we able to lay aside the problems of the time, and turn to a project whose great value lies in the enrichment of the human spirit. Today we make the achievement of another great conservation victory. We have permanently safeguarded an irreplaceable primitive area. We have assembled to dedicate to the use of all people for all time, the Everglades National Park.”

American alligator gliding through the marsh. Photo courtesy of Madeline Hirshan

According to the document entitled “Potential Ecological Consequences of Climate Change in South Florida and the Everglades,” species responses to climate change have not been extensively studied, however dramatic changes are very likely to affect certain species as well as important vegetation. For example, fish can be impacted by changes to the water chemistry including dissolved oxygen and changes in pH resulting from increased carbon dioxide in the atmosphere, and increased water temperatures. Amphibians and reptiles are also sensitive to changes in temperature and other environmental factors. Amphibian immune systems are highly reliant on temperature, so alterations to temperatures can be extremely significant. American alligators and crocodiles which are key inhabitants of the Everglades can also be affected by their changing environment. However, alligators are likely to be more adversely affected than crocodiles, as they inhabit the southern tip of their range. Alligators play a significant role in the Everglades acting as a “keystone species” playing a vital role in the ecosystem. Alligator nests serve as habitats and refuge for other species.

The two national parks presented above, are two unique ecosystems that contain a plethora of diverse species that thrive in these environments. Changes in aquatic ecosystems can be extensively linked to changes in climate and some species which rely on certain temperature or salinity environments for survival are likely to be affected. Stay tuned for next week’s post about solutions and strategies to monitor and mitigate the risks of climate change in national parks.