Wetland Losses and Human Impacts

Transcription

1 Wetland Losses and Human Impacts Matthew J. Gray University of Tennessee Distribution of North American Wetlands Peatlands of Alaska and Canada Hudson and James Bay Wetlands Prairie Potholes Great Lakes Wetlands Sacramento Valley Coastal Wetlands Everglades 30% of World s Wetlands Playa Lakes MAV Pre-Settlement in Lower US 89 mil ha United States: 3.5% of U.S. Area Canada: 14% of Canada Lower US 29% Alaska 22% Current North American Wetland Estimates Lower 48 and Hawaii =42 mil ha (89 mil) Alaska =69 mil ha 53% Loss** =111 mil ha Manitoba (22.5) =127 mil ha Ontario (29.2) = 51.7 mil ha =238 mil ha 41% Pre-settlement Canada 49% Lower US 18% Alaska 29% Current Canada 53% 1

2 Current Acreage of Wetland Types in the United States 1997, 2007 (x 1 mil ha) US Wetlands Dominated by Peatland Alaska (Minnesota Michigan) Forested Wetlands Most Common Lower 48 Estuarine wetlands are most common coastal wetland (x 1,000 ha) Gulf of Mexico Louisiana Distribution & Evolution of Peatlands Precipitation > Evaporation Accumulation > Decomposition 25-50% Anaerobic Fens Bogs Sedges & Tamarack Moss & Spruce ph > 5.0 ph < 4.0 Discharge Recharge Terrestrialization Lakes Wetlands 1% 2.5% Tennessee Wetlands Approximately 3% of Land Area 26.7 Million Acres 780,000 ac. Rivers 0.5% 316,000 ha (0.8% of Lower US) Rivers 4% Farmland 44% Forest 52% Lakes 39% Wetlands 57% All Land Uses Broad-leaved and needle-leaved Deciduous Water Cover 2

3 Wetlands: A Barrier to American Progress! 47 Million ha of Wetlands Lost in Conterminous United States Swamp Land Acts of 1849, 1850, and 1860 Federal wetlands sold to states (26 mil ha) USDA Agriculture Conservation Program Drain wet farmland (23 mil ha) 1940s 70 the 1.6 million acres of cutover cypress swamps in Louisiana must be put into their true function agriculture. It is important to Louisiana, the South and Nation as a whole. State Legislation 4X Size of Tennessee! Sinister Image of Wetlands State Wetland Losses 53% in Lower US See Handout! Midwest Breadbasket Region! Most % Loss: Arkansas = 91% California = 91% Ohio = 90% Iowa = 89% Missouri = 87% Indiana = 87% Illinois = 85% Kentucky = 81% Most Total Loss: Florida = 3.6 mil ha. Louisiana = 3.0 mil ha. Illinois = 2.8 mil ha. Mississippi Alluvial Valley Wetland Losses 77% of Hardwood Bottomland Forests 8.5 Million ha 2 Million ha Most Remaining Parcels are Seriously Fragmented 3

4 Tennessee Wetland Losses 60% Loss 1.2 Million ac. 486,000 ha $1,000/ac Most in west Tennessee Does not Mean Cannot Destroy State Legislation No Net Loss Policy Tennessee Wetlands Acquisition Act (1986) Real Estate Transfer Tax $67 Mil. $7 mil. annually to TWRA (⅔, ⅓) Purchase 62,494 ac. wetlands Current Rates of Wetland Loss 0.1% Loss per year 47,000 ha Early 1900s: s: 1980s: 1990s: 490,000 ha per year 1.1% per year 185,000 ha per year 0.4% per year 116,000 ha per year 0.25% per year 47,000 ha per year 0.1% per year Smoky Mountain National Park 211,000 ha So, the equivalent to approximately 22% of Smoky Mountains National Park is being lost each year! Each 4.5 years, total wetland area equivalent to the park size is lost! Draining Wetlands #1 Loss of Wetlands Mostly for Agricultural Use Midwest & SE Tulloch Rule Overturned, 1997 Drainage Ditch, Clay Tiles, Plastic Pipes Pits & Pumps Floating or PTO-driven Pumps 4

5 Deforestation Agricultural Use Especially in SE Many Hardwood Bottomlands cut First for Timber $250/ac Fragmentation Cotton, rice, soybeans Levees and Channelization Prevent Overbank Flow Flood Control Acts Drain Adjacent Landscape Quickly MS River Levee 5X or 80% Flood Control Ironic! Navigation & Transportation Intracoastal Waterway Filling Wetlands Concrete Runoff Primary Causes Urban Development Highway Construction Secondary Sedimentation Erosion Agricultural Runoff Bank Destablization ⅔ of World s Population on Coasts 95% CA 5

6 Water Pollution Oil Spills Fertilizers, Pesticides Erosion Cattle Discharges Chemical Temperature Before After World Peat Resources 1.9 Trillion Tons Russia (770 bt) Canada (510 bt) US (310 bt, 16%) Biological Deserts Peat Mining World Peat Mining 1) Finland 2) Ireland 3) Russia Non-renewable Resource Fuel 70% Annual Production Fuel= Hort= 16.8 mil tons 6.9 mil tons Horticulture 23.7 mil tons United States 676,000 tons (Horticulture) 30% Largest Commercial Fisheries Louisiana Coastal Erosion 40% of Coastal U.S. Marshes Channelization of MS River Reduced Sedimentation Barrier Islands Increased Saltwater Intrusion Rising sea levels 34 sq miles per year 1900 sq miles (Delaware) ft inward loss per year At the current rate of loss, by 2050, ⅓ of coastal LA will have eroded into the Gulf of Mexico! 6

7 30 min = 1 football field Louisiana Coastal Erosion 1 mile = 1-ft buffer in storm surge Hurricane Katrina St. Bernard and Plaquemines parishes 30-sq miles loss in Brenton Sound Storm Surge in Lake Pontchartrain ft, ft $50 million annually $500 mil for 30 years Coastal Louisiana before Katrina Lake Maurapas USGS LandSat Image Lake Pontchartrain Brenton Sound Hurricane Katrina $29 bil Andrew Category 4 29 August :10 a.m. EDT 976 Deaths in LA, 218 in MS $40 60 Billion Claims >$125 Billion Economic 7

8 Coastal Louisiana after Katrina Before Before After After Chandeleur Islands Cutting Louisiana s Cypress Sloughs Dr. Gary Shaffer, LSU 80% would not Regenerate 8