Archive for the ‘Vol 7 No 4 – December 2008’ Category

Learning the Lessons of History

Tuesday, December 23rd, 2008

Aerial view of the Chesapeake BayH.G. Well’s quote that “history is a race between education and catastrophe” resonates clearly in the Chesapeake Bay. Natural history and observational science have formed the cornerstone of our understanding how the Bay has changed over time –– tracking periods of abundance and decline, holding clues to the future. But moving forward, the question still remains as to whether an understanding of history will prevent us from repeating past mistakes.

Long-term data streams abound in the Bay region. Fisheries harvest data tell the tale of declining oyster populations, of the crash and recovery of the striped bass. Some of these go back more than 100 years. Mud samples taken from the bottom of the Bay show how the abundance and diversity of bottom-dwelling creatures has changed over time, a data set that extends back some 25 years. Field sampling annual aircraft surveys of phytoplankton and aerial surveys of underwater grasses paint a long term picture of the Bay’s change in state –– declines in underwater grasses followed by recurrent population explosions of algae.

There are comparatively fewer long-term natural history data sets, rich information records that document the ebb and flow of populations of organisms over time. But like Ohio University biologist Willem Roosenburg, featured in the latest Chesapeake Quarterly, several other natural historians have helped contribute a long-term record of life and change in the Bay. Vernon Stotts, with the Maryland Wildlife Administration, studied the change in waterfowl populations for more than two decades. He was among the first to note the decline of underwater grasses in the early 1970s, when he realized that many birds had begun feeding off plants in farm fields instead of in the water. Dave Cargo, who worked at the University of Maryland Center for Environmental Science Chesapeake Biological Laboratory, created a long-term record of sea nettle abundance through a daily census off the lab’s dock on the Patuxent River. Beginning in 1960, this data collection continued after Cargo’s death and now holds more than 40 years of information on population abundance, data that has provided clues to changing predator-prey relationships in the Bay.

Long-term data records of water quality, climate, river flow, and temperature also provide key information on how the Bay has changed over time. Since the creation of the E.P.A. Chesapeake Bay Program in 1984, detailed monitoring efforts have kept track of estuarine variables for water quality, such as turbidity, algal species, oxygen, anoxia, nitrogen, and phosphorus. Watershed variables, such as nutrient and sediment loading, land use, and impervious surface cover provide the raw material for making the link between human activities on land and in the water and changes in the estuary.

But will what we know about the Chesapeake’s past, guide the Chesapeake’s future? The Bay seems well poised to learn from the lessons of history, but sometimes it is hard for scientists to slow down frenetic pace of research to look back to the past for clues to the future. One of the primary recommendations from a conference on Thresholds in the Recovery of Eutrophic Coastal Ecosystems, held in 2007 and jointly sponsored by Maryland Sea Grant and the Chesapeake Bay Program Scientific and Technical Advisory Committee, was to tap into the wealth of historical data that already exists to predict how the Bay will respond to restoration efforts in the future. This means rigorously studying and synthesizing the past, while simultaneously monitoring the environmental conditions of the present. Standing on the shoulders of the vigilant natural historians and field scientists who have kept a close eye on the Bay for all of these years, maybe the time has come to take a closer look across systems, to seek signs of concurrent trends from different organisms, different time series. Only by understanding where the Bay has been, will we be able to shape where it is going.