When asked about the most important habitats for biodiversity and carbon dioxide sequestration, most people will respond with the rainforest or coral reefs. However, very few recognize the immense benefits that wetlands provide for natural habitats, human utilization and climate change mitigation. Wetlands have been disrupted for centuries for agriculture and human urbanization, but we now need wetlands more than ever as a mitigation strategy against rising sea levels, increasing levels of greenhouse gases and decreasing biodiversity.
According to the Environmental Protection Agency, or EPA, wetlands contain a wide variety of species from microbes, amphibians, insects and fish to reptiles, birds and mammals. Wetlands can be thought of as “biological supermarkets” because of the large amount of food they provide for other species by breaking down dead plants to feed aquatic insects and small fish. This not only helps those specifically eating the detritus (dead organic plant matter), but then feeds the entire food web, stimulating the habitat to continue to grow and successfully maintain its species.
For humans, wetlands not only provide local fishing sites and timber, but recreational use leading to an economy for tourism. Wetlands can then be viewed as mutually beneficial, as they cycle nutrients and filter pollutants while still allowing people to enjoy them in day to day life.
Unfortunately, wetlands are being degraded through additions of pesticides in neighboring fields and lack of fertility replacement, according to research from the USDA. The buffer that natural wetlands serve between agriculture and other ecosystems is slowly degrading, thereby harming humans and wildlife.
In Northern California, the wetlands of Point Reyes are a prime example of a very biodiverse ecosystem that has been through challenges but is in the process of rehabilitation. Point Reyes is located 60 kilometers northwest of San Francisco and comprises 130 kilometers of exposed and protected shorelines, amazing coastal cliffs, headlands, lagoons, grasslands and forested ridges. Thirty kilometers of shoreline are home to coastal dune habitats that support 11 federally listed threatened species, according to findings from the U.S. Department of the Interior.
Unfortunately, in the 1940s, many parts of the Point Reyes National Seashore, or PRNS, became dammed for dairy ranching and crop agriculture. Because many wetlands offer fertile, moist soil, the regions they once inhabited are prime areas for crops to grow. When the National Park Service began to advocate for protecting natural habitats, many ranchers decided to sell their land to the government for the people to once again enjoy the beauty of wetland ecosystems.
As researchers began to study the PRNS, they noticed the changes in vegetation communities and bird populations when compared to thriving wetland communities. This distinction validated the need to rehabilitate many of the coastal wetlands along Point Reyes in order to return the hydrological and ecological functionality of what once existed. Tomales Bay, a specific region of the PRNS, has been extremely deteriorated over the last century because of sediment quality issues, non-native species invasions and excessive sedimentation.
The EPA notes that in order to rehabilitate these ecosystems, ecologists review the specifics of what that particular region needs to become ecologically successful which can range from removing invasive species, stream channelization, improving water quality or bringing back native biota. Every wetland, like any other ecosystem, is complex in its own way depending on topography and geographical location so it is important for biologists to analyze the many factors at play to create a viable solution.
Estuary and marine fish need coastal wetlands to survive and restoring these habitats wildlife diversity can once again return. The National Park Service notes around a third of the threatened and endangered species in the United States live in wetlands, making it extremely important to protect wetlands from future degradation.
Equally as important is the role wetlands play in climate change and human functions. Wetland ecosystems store large amounts of carbon in their plant life (kelp, trees, shrubs, plankton, etc,), which allows carbon to escape the atmosphere. By having places for carbon to sequester itself, these toxic gases are no longer present in the atmosphere which is beneficial for reducing temperatures and improving human health.
As hurricanes and flooding become more prevalent in certain parts of the globe, wetlands (marshes, bogs, swamps, mangroves) are a key tool to have as they act as natural sponges that trap and slowly release any surface water or rain, snowmelt and groundwater. Preserving and restoring wetland habitats can provide a level of natural flood control against increasing numbers of storms and hurricanes due to climate change.
David Moreno-Mateos, researcher at UC Berkeley who obtained his doctorate while studying wetland restoration in Spain reiterates the importance that it is better to “preserve the wetland, not degrade the wetland” in the first place. Mateos describes that restored wetlands contain about 23% less carbon than untouched wetlands after 50-100 years of restoration because plants take much longer to return to the same capacity of carbon sequestration. As such, we must make the first priority to preserve existing century-old wetlands, while still placing attention on rehabilitating those that have been degraded.
Not only is this present in Point Reyes, but is local to residents of the Bay Area in the wetlands that line the San Francisco Bay. We can see wetlands in the Berkeley Marina and in Marin County where massive restoration is currently in progress.
Although wetlands may not be viewed as an important asset in the fight against climate change among the public, they have a huge impact on decreasing emissions, among many other benefits. Not only can habitat restoration booster a local economy, but make a huge impact in the progress to reach a greener world.