Tag Archive | "sea level rise"

Blackwater Map

Wildlife Refuges on Deck for Land Aquisition Funding Vulnerable to Sea Level Rise

There are over 150 national wildlife refuges located in coastal areas, yet the Refuge System has not adequately incorporated projections of sea level rise or other climate impacts into land acquisition planning.  Thus, the U.S. Fish and Wildlife Service may not be maximizing the effectiveness of its conservation investments if it is making fee-title acquisitions or purchasing long-term easements on lands that are going to be underwater within a few decades.

To get a better picture of the situation, we used the Sea Level Affecting Marshes Model (SLAMM) to assess the threat to the lands within both the acquired and approved boundaries of eight coastal refuges that have been assigned a high funding priority for land acquisitions in the coming year.

We found that sea-level rise impact will not be felt equally among coastal refuges. Great White Heron NWR, in the Florida Keys, is the highest ranked refuge for land protection funding for FY 2013 by the Fish and Wildlife Service, yet it is extremely vulnerable to sea level rise. Two of the refuges we assessed, Great White Heron and Blackwater, face potential net loss of over 40% of refuge lands by 2075, if sea level rises by one meter over the course of the century. On the other hand, four of the refuges have less than 5% of their land area vulnerable. Some refuges, like Blackwater, will face inundation but have newly created wetlands nearby, where the refuge could potentially expand to. Others, like Laguna Atascosa NWR, will face wetlands loss that will not be readily replaced with new areas of marsh. And refuges whose land area consists mainly of low-lying islands, like in the Florida Keys, may run out of land entirely.

 

 

 

 

 

 

 

 

 

 

 

 

 

The Fish and Wildlife Service urgently needs to better understand and incorporate climate change and sea level rise implications into its land acquisition planning to avoid investments that will ultimately be literally under water.

Our summary report with policy recommendations is available here.

The complete report is available here.

Posted in Climate Change, National Wildlife RefugesComments (1)

sunset refuge

National Wildlife Refuges and Sea-Level Rise

The Refuge System is losing ground. Literally. There are over 160 coastal national wildlife refuges, and virtually all of them are experiencing the impacts of sea level rise and coastal storms exacerbated by climate change. Refuges need a system-wide response.

Defenders recently published a new report, National Wildlife Refuges and Sea-Level Rise: Lessons from the Frontlines, based on insights from a national perspective as well as on the ground at Alligator River National Wildlife Refuge in North Carolina and Chincoteague National Wildlife Refuge in Virginia. The report includes recommendations for national policy, on the ground habitat management, and for dealing with local communities, many of which are resistant to the management changes necessary to cope with the rising seas. These recommendations include:

To respond to it effectively, refuge managers must:

• Take a landscape-scale approach to conservation throughout the refuge system.

• Share information throughout the refuge system to avoid ‘re-inventing the wheel’ in responding to climate change.

• Receive policy guidance and support from FWS for coordinated climate change responses throughout the refuge system.

With sufficient financial support and manpower, coastal refuges can take steps to help mitigate the impacts of sea-level rise and buy time for species and habitats to adapt to the impacts of climate change. Steps that show promise include:

• Plant salt-tolerant species to minimize the impacts of saltwater intrusion.

• Restore altered hydrology to reduce salt-water intrusion and to regain natural marsh-building processes.

• Restore shoreline reefs to minimize climate-change-mediated coastal erosion.

• Work with partners and the public to develop long-term conservation plans for the next century and beyond.

 

A large and growing percentage of the American public is skeptical or confused about climate change. To build understanding and support for climate-change-related work at refuges, managers and staff must engage and convince the people who live near refuges. To do this, refuge managers need support and guidance from FWS to:

• Find and present tangible examples the local community can relate to of sea-level-rise impacts that have already occurred.

• Use modeling tools such as SLAMM to provide dramatic, easy-to-grasp visuals of what the landscape will look like in the future.

• Engage in an open community dialog to find out what’s important to locals and to explore alternatives for reaching their goals.

Only by taking a broad, new perspective to finding creative solutions for addressing climate change-related problems and to educating and involving local communities and partners can FWS meet its conservation mission and preserve our refuges, the network of special places where the needs of wildlife come first.

Posted in Climate ChangeComments (0)

Bringing Better Tools to the Study of Sea Level Rise

A thorny problem for climate change adaptation is figuring out how to sort through projections and uncertainties to make a better determination of what impacts to expect. Two studies – one newly published, the other just underway – show promise for a better understanding, and therefore a more informed response, to the problem of sea level rise and its impacts on coastal ecosystems in California.

One of the more challenging issues related to climate change is the extent and timing of future sea level rise. While there is broad consensus that ocean levels will rise this century, due to a combination of melting of land-based ice, and the thermal expansion of ocean waters, it is very difficult to estimate the rate of this rise: for instance the 2007 IPCC report authors decided that they didn’t have enough information to determine the effects of changes in polar ice sheets, so they left them out of their projections. Since that time, scientists have refined measures to estimate the climate change impacts on the rate of flow of large ice sheets. Thus, while the IPCC’s 2007 sea level rise estimation was eight inches to two feet by the end of the century, by 2009 the US Global Change Research Program projected 3-4 feet of average sea level rise worldwide.

However, the story is not as simple as that. Sea level rise will have different impacts in different areas, depending on whether the land is also undergoing a natural subsidence (as is the case in the Chesapeake Bay region, where the land is still settling after the last Ice Age), and also on the amount of sediment being carried to coastal areas by the region’s river systems (for instance, multiple upstream dams deprive the Mississippi delta of much-needed sediments). Thus, predicting the future of a given marsh, for instance, is a function of both sea level rise and the relative rate of natural sediment accretion or subsidence. In a new study published in PLoS One, researchers at the Point Reyes Bird Observatory combined the best-available knowledge about rates of sediment deposition with scenarios for sea level rise to ascertain possible futures for the San Francisco Bay. They found that under the worst-case scenario, with high sea level rise (5 feet) and low levels of accretion of sediment and organic matter, the San Francisco Bay could lose 93% of its existing marsh within 50 to 100 years (human activities have already reduced tidal marsh in the Bay by about 90% from its historic extent). However, the authors also note that this worst-case outcome can be avoided by “conserving adjacent uplands for marsh migration, redistributing dredged sediment to raise elevations, and concentrating restoration efforts in sediment-rich areas.” They have developed a planning tool to help conservation practitioners where and when these changes would take place, to better inform restoration and land acquisition decisions.

The second study, recently announced by the California and North Pacific Landscape Conservation Cooperatives, will examine the impacts of sea level rise at five National Wildlife Refuges from Humboldt Bay in northern California, to Tijuana Slough near San Diego. The study, the first of its kind to monitor SLR impacts in such detail over such a long stretch of coastline, will “develop high-resolution digital elevation models (DEMs); monitor water levels and tidal cycles to assess local-level inundation patterns; inventory vegetation species composition and relationship to elevation and tides; and quantify sensitive wildlife use at all five refuges.”

Coastal marshes are incredibly productive habitats that supply food and shelter to a array of birds and other wildlife, and serve as nurseries for many ecologically and commercially important species. Already greatly diminished by shoreline development, pollution and activities like dredging and ditching, these systems are also on the front lines of the impacts of climate change. These new tools may hold the key to helping managers and planners enable marshes to adapt to and move with the rising sea.

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Chesapeake Bay tidal marsh, David Curson, Audubon MD/DC

Climate Change Adaptation in Maryland’s Somerset-Wicomico Marshes Important Bird Area

Chesapeake Bay tidal marsh, photo by David Curson, Audubon MD/DC

The State of Maryland is moving forward with critical climate change planning for coastal areas by figuring out how to protect lands into which soon-to-be-inundated wetlands and marshes can retreat. In response to the threat of sea level rise, these efforts are essential to maintaining the long-term ecological functions of storm surge buffering, carbon sequestration, water filtration, wildlife habitat, recreation and others that wetlands provide.

Defenders of Wildlife, Audubon Maryland/DC and the Lower Shore Land Trust have teamed up on a project focused on increasing the adaptive capacity of salt marshes and salt marsh obligate bird species in the Somerset-Wicomico Marshes Important Bird Area

View video on Climate Change Adaptation in Maryland’s Somerset-Wicomico Marshes Important Bird Area

The coastal wetlands in the Chesapeake Bay provide a range of “ecosystem services” that are critical for improving the water quality by helping to remove nutrients, chemicals, and sediment from urban and agricultural runoff before reaching the open water of the Bay. In addition, coastal wetlands provide a first line of defense against rising sea levels and increased storm damage, flooding and erosion.

These wetlands are habitat for ducks, geese and shorebirds and are home to unique flora and fauna, including two birds, the Seaside Sparrow and the Saltmarsh Sparrow, which are identified as Maryland species of greatest conservation concern in the Maryland Wildlife Diversity Conservation Plan. These species evolved in this tidal environment and are found only in salt marsh habitats along the U.S. Atlantic Coasts.

Sea level rise is impacting low-lying coastal lands at twice the global average rate. Maryland Department of Natural Resources explains that the State has already seen a foot of relative sea level rise during the past 100 years, causing the disappearance of 13 barrier islands from the Chesapeake Bay. Within the Chesapeake Bay, additional sea level rise impacts are already evident, including wetland erosion and forest die-back as a result of saltwater intrusion.

Our work will focus on assisting the Lower Shore Land Trust to identify the highest priority marsh migration corridors so that they can protect these areas from future development. This project takes place within the context of Defender’s work with state wildlife agencies to update their wildlife action plans to consider the impacts of climate change, as well as Defender’s Living Lands program that enhances the capacity of land trusts and their partners in protecting biodiversity in the face of climate change.

For more information on sea level rise in the Chesapeake Bay, see the following online resources:

Maryland Commission on Climate Change  

Strategy for Reducing Maryland’s Vulnerability to Climate Change Phase I: Sea-level rise and coastal storms

National Wildlife Federation

U.S. Climate Change Science Program

North Atlantic Landscape Conservation Cooperative

Posted in Climate Change, Imperiled WildlifeComments (0)

A photo of an estuary

At the front lines of climate change

A photo of an estuaryEstuaries, the ecosystems that exist where rivers and oceans meet, are at the front lines of climate change. Rising sea levels threaten to inundate coastal wetlands, increasing their salinity and causing a shift in vegetation communities. Air and water temperatures, precipitation patterns, and ocean chemistry are also changing. All of these processes likely add up to a loss many of the values these systems provide, including providing habitat for fish, migratory birds, and other species, filtering water, stabilizing shorelines, and buffering coastal communities from storm damage.

On November 18-19th, a group of researchers and managers got together in Newport, Oregon, to mull over what to do about this situation. We asked ourselves:  How can we best manage these sensitive ecosystems so that they continue to provide fish and wildlife habitat and other important values as the climate changes?

The question is a particularly tough one, because relatively simple physical changes in climate and water chemistry will create complex effects in biological systems. For example, we know that air temperatures here in the Pacific Northwest are likely to rise some 2-5°F over the next several decades and that we can expect on the order of 3-4 feet of sea-level rise globally by the end of the century (although the magnitude of sea-level rise remains much debated).  These changes are likely to affect factors that are critical to estuary function like water salinity, sediment deposition, and vegetation type, but we know relatively little about exactly how these cascading effects will play out on the ground. As a result, many managers feel that climate change projections are still too uncertain to inform management decisions

One of the conclusions from the group was that many of the conservation tools we already have will be useful in responding to climate change. For example, many estuaries can effectively migrate inland as sea levels rise. Where they are hemmed in by development, though, they are unable to shift and some of their function and value as wildlife habitat is almost certain to be lost, so protecting coastal lands from development through conservation easements and purchase is vitally important. We also discussed some creative strategies for managing estuaries and the riparian areas that feed them, such as reintroducing beavers into streams and rivers improve water storage on the landscape and help moderate water flows.

Many of these strategies are robust to uncertainty, in the sense that they are very likely to be beneficial even if we are wrong about the magnitude or effects of future changes in the climate. Developing more of these robust strategies will help keep conservationists from becoming paralyzed by the uncertainty inherent in climate prediction and modeling. In Oregon, the next step is to delve deeper into some of the solutions we identified and start thinking critically about what tools to use, where, and why. We’ll also be working to spread the word so that that general public is more aware of likely climate change impacts and our options for managing it.

Posted in Climate Change, Pacific NorthwestComments (0)


dotWild is the blog of scientists and policy experts at Defenders of Wildlife, a national, nonprofit membership organization dedicated to the protection of all native animals and plants in their natural communities.

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