Impact of Colonial Farming and Oysters on Chesapeake Bay Ecosystem Change

1. Lecture 8: Anthropomorphic Change Farming, Oysters, & Succession

2. Objectives • Understand how the colonists altered the land surrounding the Chesapeake Bay • Understand how the colonists altered the near-shore communities of the Chesapeake Bay

3. Farming • Indians method of farming maintained the topography of the land • No metal implements e.g. axes or plows • treated land as gift from Manitou • Colonists method of farming altered the topography of the land • Metal implements used to fall trees and till soil • Land belonged to colonial user

4. Tobacco • Chief cash crop of colonists (big buck export item used to make cigars) • First cultivated in Chesapeake Bay Region by John Rolfe (came from West Indies) • Demands rich soil • Depletes soil of nutrients in ~ 5 yrs. so there was a great need to clear more land • Labor intensive crop demanding additional workers

5. Tobacco Pictures • Tobacco requires • early germination under burlap • planting • topping • harvesting • drying • rotation

14. Oysters • Sessile (cannot move so cannot run away) • Tasty? • Can be eaten year round although best during months of the year containing “R” • Readily available during colonial time

15. The Oyster Story

16. Oyster Pictures

17. The Oyster Story • Oysters record changes in Bay conditions • “Meats” accumulate heavy metals & environmental toxins as a result of the oysters feeding via the “filter” method. • “Shell” is a permanent record of Bay conditions and position in the water column. The shell (mantle) grows daily trapping water within the shell. Growth is modified by temperature and pressure

18. Oyster Story • 3 shell morphologies • Sand oyster: • ridges on shell • height roughly = width • Mid-water oysters • no pronounced ridges • length exceeds width • Tongue Oysters • length >> width

19. Colonial Garbage • Colonists did not have indoor plumbing so they utilized Privies (out houses). • Several times a year the “waste” material would be layered with dirt and shell to reduce odor • Trash was also disposed in a pit (typically an old well) and routinely layered with shell

20. Oyster Analysis • There is a gradual change in the kind of oyster shell morphology correlated with the length of time a “colony” existed at a particular site • The early “privy “ layers have predominately sand oyster shell morphology but the newer layers have mid-water shell morphology

21. Summary • Tobacco farming initiated change in near shore terrestrial communities • Loss of tree cover • Loss of food for animals • Soil nutrient depletion • Erosion • Changes in near shore aquatic communities can also be documented • over use of resources

22. References • http://www.gmu.edu/bios/bay/cbpo/intro.htm#wetlands • http://www.inform.umd.edu/wetlands/index.html