The Importance of the Pearl River to Mississippi s Estuarine Habitats Jennifer Buchanan Education Coordinator

Transcription

1 The Importance of the Pearl River to Mississippi s Estuarine Habitats Jennifer Buchanan Education Coordinator 2006 Pearl River Basin Symposium May 5-6, 2006

2 Topics for Discussion What s an estuary? Pearl River s zone of influence along the coast Mississippi s estuarine habitats The role the Pearl River plays in maintaining estuarine biodiversity Ecosystem-Based Management

3 Estuary Saltwater (Sea) Brackish Water may flow in a thousand channels, but it all returns to the sea African Proverb Freshwater (Rivers)

4 Zone of Influence

5 Coastal Ecosystems Just as no single life form (species) is sufficient unto itself, neither is any one ecosystem. Ecosystems and their plant and animal life are not independent from one another in time, space, or energy. -Louis A. Helfrich and James Parkhurst

6 Mississippi s coastal ecosystems are mosaics of diverse coastal habitats all interconnected

7 Impacts to Biodiversity H = Habitat Destruction I = Introduced Species P = Pollution P = Population Growth O = Over-consumption

8 Freshwater Inflow

9 Why is the freshwater from the Pearl River important? Freshwater Inflow Quantity Timing Quality Estuarine Conditions Salinity Sediment Dissolved Material Particulate Material Pathway Estuarine Resources Species Composition, Abundance & Distribution Primary & Secondary Production Modified from Georgia Coastal Research Council

10 Quantity is affected by: Withdrawals from upstream Drinking water Industrial/Agricultural Impoundments Dams Reservoirs Diversions Canals Navigation Pearl River Navigation Channel 1950 s

11 Timing is affected by: Operation of reservoirs Releases Storage Changes in land use Forest to urban Channelization Removal of riparian buffers Ross Barnett Reservoir

12 Quality is affected by: Upstream changes in inflow that affect: Amount Timing Point and Non-point Source Pollution. (Increased organic materials and sedimentation and sometimes just the reverse)

13 Decreased Flow and Estuarine Conditions Increase in Salinity Leads to saltwater wedges and intrusion May cause the estuary to enlarge Many animal and plants species may be adversely impacted (habitat structures may even shift) Species composition and distribution will change

14 Decreased Flow and Estuarine Conditions Change in Mixing Patterns Makes the estuary more dependent on the tides for mixing tidal amplitude can actually increase May cause the waters of the estuary to shift in stratification and form hypoxic zones

15 Decreased Flow and Estuarine Conditions Change in Transit Time The time it takes to flush out the system is increased the water movement slows down Pollutants and pathogens may become more concentrated Some backwater areas may become stagnant

16 Decreased Flow and Estuarine Conditions Change in Geomorphology Because freshwater is often also a source for sediment input, decreased flow can result in a loss of sediment needed to renourish tidal deltas and benthic and intertidal habitats Can lead to subsidence of marshes

17 Changes in Flow and Estuarine Conditions Change in Dissolved and Particulate Materials Impacts depend on the type of estuary and the quality of the water Increased water flow in the Pearl during flood conditions contribute to a spike in fecal coliforms and sediment that contaminate our oyster reefs and swimming areas Decreased flows often initially lead to an increase in primary production (less turbidity) but then a decrease occurs due to the loss of nutrient input

18 The structures causing the decreased flow additionally lead to problems Dams, weirs, levees and other water-control structures create barriers that endangered Gulf Sturgeon and other anadromous species cannot get over in order to reach their breeding areas Water is often released when the estuaries already have too much freshwater and withheld when they are in need of it Much of the lower river is so shallow that recreation is restricted

19 The structures causing the low flow additionally lead to problems (cont.) Once areas begin to dry up, heavy equipment can get in and clearcut and replace one habitat type with another less diverse type Bottomland hardwoods replaced by pine plantations

20 Ecosystem-based Management Ecosystem-based management (EBM) is a management approach to restore and sustain the health, productivity, and biological diversity of ecosystems and the quality of life of humans who depend on them.

21 Ecosystem-based Management This system knows no political boundaries

22 Port Bienville

23 Interstate-10

24 Mouth of the River

25 Stennis Space Center

26 The split in the river 50 miles inland near Picayune

27 Watershed impoundments

28 There is a difference between occupying the land and living in a land-- --we must come to appreciate our cultural and ecological resources We abuse land because we regard it as a commodity belonging to us. When we see land as a community to which we belong, we may begin to use it with love and respect. Aldo Leopold A Sand County Almanac