As one of the most vulnerable regions in the nation to the effects of climate change, all aspects of life in the Chesapeake Bay watershed—from people and critters, to habitat and infrastructure—are at risk from its effects. Warming air and water temperatures, sea level rise and extreme weather events are expected to have a significant influence on the Bay region in the coming years, but many changes are already being documented. With recent record-breaking high temperatures, including last year and the first quarter of this year, some species are feeling the heat.
1. Cherry blossoms. Thousands of iconic cherry trees surround the Tidal Basin and national monuments of Washington, D.C., and their blossoms bring countless visitors to the area. Over the past 90 years, cherry blossoms have been blooming earlier, due in part to increasing average seasonal temperatures. Since 1921, Washington’s average March temperatures have warmed more than two degrees Fahrenheit, leading “peak bloom” for the cherry blossoms to shift five days earlier.
2. Chickadees. Two strikingly similar types of chickadees are common in backyards through the United States: in the Southeast, the Carolina chickadee is most common, while the black-capped chickadee dominates the northern states. A narrow band of overlap, called the “hybrid zone,” is where the two chickadees meet and interbreed—and it has been steadily moving northward as temperatures rise. According to one study, the zone has been shifting nearly 0.7 miles each year, moving a total of 7 miles in the past ten years.
3. Migratory waterfowl. The Bay region is a key stop for millions of migratory waterfowl during their seasonal flights. But milder winters have caused several bird species to visit in smaller numbers. Many canvasbacks have been stopping short along their migrations due to warming temperatures; one report shows the number of wintering canvasbacks in the Bay region declined from nearly 250,000 in the 1950s to 30,000 in recent years. Some tundra swans have been wintering on open rivers in Canada rather than the shallow waters of the Bay. These changes in waterfowl migrations can take a particular toll on recreational hunters, who are seeing fewer birds migrate through the region later in the season.
4. Fish. Nearly 350 species of finfish swim through the rivers, streams and open waters of the Bay region, and many of these species are particularly sensitive to changes in water temperature. Research suggests that the temperature at which native and migratory fish begin to spawn or migrate (typically 15 degrees Celsius) is occurring nearly three weeks earlier than it did in 1960. In particular, the black sea bass has been rapidly moving its range northward; communities in North Carolina who have typically caught a majority of the black sea bass catch have recently been traveling as far north as New Jersey to meet their quotas.
5. Bay grasses. Underwater grasses are a critical part of the Bay ecosystem, providing food and shelter for some of the Bay’s most iconic species, including young blue crabs. Bay grasses are particularly sensitive to excess rainfall and changes in temperature, meaning warming temperatures and more frequent, more extreme weather events are impacting their health. High temperatures during a 2005 heat wave are blamed for a massive die-off of eelgrass in the Bay, and while many areas have rebounded from the collapse, some eelgrass beds have not yet recovered.
6. Pine beetles. A changing climate doesn’t just affect the iconic, treasured species of the Bay region—it also make it easier for invasive species and pests, like the southern pine beetle, to move in. No bigger than a grain of rice, these beetles burrow under a tree’s bark and consume a layer of the tree, which disrupts the flow of nutrients and typically kills the tree in less than four months. Historically, the beetles were unable to survive north of Delaware. But warming temperatures, especially in the winter months, have allowed the pest to migrate northward along the East Coast, reaching as far as New York.
As environmental conditions continue to change, even more species will be threatened by rising seas, warming temperatures, extreme weather and habitat loss. Under the Chesapeake Bay Watershed Agreement, Bay Program partners are committed to building the climate resiliency of the animals, plants, habitats, infrastructure and communities throughout the region.
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The Chesapeake Bay’s blue crab population has seen a modest rise, increasing 38 percent since the population was counted last winter. While an increase in blue crabs is an indicator of Bay health, the adult female crab population remains below its target, indicating the variability of the blue crab population and the complexities of managing the fishery.
Maryland and Virginia measure the Bay’s blue crab population through an annual winter dredge survey. Over the course of three and a half months, scientists visit 1,500 sites around the Bay, using metal dredges to pull up crabs over-wintering in the mud.
Results of the 2015 winter dredge survey show the Bay’s total blue crab population has increased from 297 million to 411 million since last winter. Results also show the number of spawning-age females has risen from a depleted 69 million to 101 million. The number of juvenile crabs has jumped from 199 million to 269 million, which is just above the long-term average.
According to the Maryland Department of Natural Resources (DNR), the cold winter and resulting low water temperatures contributed to a “substantial mortality” among blue crabs, killing an estimated 19 percent of adults.
“We are pleased that crab numbers increased despite the harsh winter temperatures,” said DNR Secretary Mark Belton in a media release.
The Chesapeake Bay Program tracks the adult female blue crab population as an indicator of Bay health. The Chesapeake Bay Stock Assessment Committee (CBSAC), which includes scientists and representatives from the federal government, state governments and academic institutions, will use this data to make recommendations on sustaining the blue crab population in its 2015 Blue Crab Advisory Report, expected to be released this summer.
Each spring, migratory fish use the rivers and streams of the Chesapeake Bay watershed to move between fresh water and the saltier ocean. Anadromous species—like American shad, hickory shad and blueback herring—return from the ocean to lay their eggs in fresh water, while catadromous species—like the American eel—move from streams to the ocean to spawn. While dams and culverts can block the movement of these fish, dam removal and fish passage construction projects have reopened thousands of area stream miles to fish migration.
According to the Maryland Department of Natural Resources, 33 fish species have ascended a fish lift, ladder or other structure in the state. While this indicates the value of fish ladders, lifts and other structures that help move fish over dams, it’s important to note the shift that new research has brought to fish passage restoration.
“Our [fish passage] program has changed over the years,” said Nancy Butowski, who manages fish passage in Maryland and serves as a member of the Chesapeake Bay Program’s Fish Passage Workgroup. “In the 1990s, it was focused on providing fish passage through ladders. But…fish passages are not 100 percent efficient. Now, we prefer dam removal.”
Dam removal can benefit a wider range of species—like the resident fish who also move up and downstream at different times of year—and the stream itself, Butowski said. Depending on the dam, its removal can even benefit human health: there have been several deaths at the Patapsco River’s Bloede Dam, which is slated for removal.
Maryland has worked with Pennsylvania, Virginia and the Nature Conservancy to develop a tool that will prioritize fish passage restoration projects. It takes close to 40 different characteristics into account, including how many miles a project would open, how much a project would cost and whether there are migratory fish currently using the waterway. Through the Chesapeake Bay Watershed Agreement, the Bay Program has committed to reopening 1,000 more stream miles to migratory fish by 2025. Learn more about our work to reopen fish passage.
A new voluntary education program aimed at increasing environmental literacy was introduced in Virginia on Wednesday.
The Virginia Environmental Literacy Challenge is intended to encourage educators to engage students with the natural world in new and creative ways, by highlighting those who excel in environmental literacy efforts. A series of lesson plans—from habitat construction to recycling projects—will accompany the challenge.
“We need to make sure that our students are graduating with the skills and knowledge they need to protect Virginia’s natural resources,” said Virginia Governor Terry McAuliffe in a release. Governor McAuliffe signed the executive order creating the program.
In supporting the outdoor education and sustainability efforts of teachers, administrators and schools, the program will help achieve the environmental literacy goals of the new Chesapeake Bay Watershed Agreement, signed last year by the Chesapeake Executive Council, the top-level leadership entity for the Chesapeake Bay Program that Governor McAuliffe now chairs.
“Environmental literacy is an important part of the Chesapeake Bay [Watershed] Agreement,” said Molly Ward, Virginia Secretary of Natural Resources and Chair of the Chesapeake Bay Program’s Principals’ Staff Committee. “A systemic approach to environmental literacy will ensure that future generations are prepared to protect and conserve our natural resources.”