Wetlands: Biodiversity Offsets: Challenges and considerations

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Written by Dave Howerter, Director of Conservation Science, Ducks Unlimited Canada

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Wetlands: Biodiversity Offsets: Challenges and considerations

  1. 1. Wetlands: Biodiversity Offsets: Challenges and considerations Wetlands: David Howerter & Karla Guyn, Ducks Unlimited Canada ecology of prairie wetlands and their importance to waterfowl
  2. 2. Outline Wetland definition Wetland Classification Wetland Values Offset Challenges DUC Experiences  Atlantic Canada  Alberta
  3. 3. What is a wetland?  “ …. land that is saturated with water long enough to promote wetland or aquatic processes as indicated by poorly drained soils, hydrophytic vegetation, and various kinds of biological activity which are adapted to the wet environment.” (Wetlands of Canada, 1988, page 416)
  4. 4. Canada’s Wetlands • there are five classes of wetlands in the Canadian Wetland Classification System: bogs, fens, swamps, marshes, & shallow water wetlands
  5. 5. Canada’s Wetlands • organic wetlands (> 40 cm of peat): - bogs - fens peatlands
  6. 6. Bogs
  7. 7. Bogs  peat-covered wetland  wetland isolated from ground water  low nutrients  water and peat usually acidic  dominated by Sphagnum mosses with tree, shrub or treeless vegetation cover
  8. 8. Fens
  9. 9. Fens  peat-covered wetland  wetland exposed to groundwater  more nutrients than bogs  less acidic  greater variety of plants than bogs: grass meadows, shrubs, and trees
  10. 10. Canada’s Wetlands • organic wetlands (> 40 cm of peat): - bogs - fens peatlands • mineral wetlands: - swamps - marshes - shallow open water
  11. 11. Swamps
  12. 12. Swamps  non-peat forming wetland  waterlogged soil, often with standing water  vegetation is dense coniferous or deciduous trees, or tall shrub thickets  water-loving plants
  13. 13. Marshes
  14. 14. Marshes  non-peat forming wetland  waterlogged soil in plant rooting zone, often with standing water  nutrient rich water offering greater plant diversity: emergent reeds, rushes or sedges  surface water level may fluctuate seasonally
  15. 15. Shallow open waters
  16. 16. Shallow open waters  non-peat forming wetlands  locally known as ponds or sloughs  standing water, often a transition between lake and marsh  fewer emergent plants but submersed plants may be present  water depth usually < 2 meters
  17. 17.  Canada has approx. 127 million ha of wetlands (24% of all the world’s wetlands)
  18. 18. Prairie Pothole Region Manitoba Montana North Dakota Minnesota South Dakota approximately 715,000 km2 Iowa
  19. 19. Stewart and Kantrud (1971)  based on vegetative growth  allows for a more detailed classification Stewart, R. E. and H. A. Kantrud. 1971. Classification of Natural Ponds and Lakes in the Glaciated Prairie Region. Resource Publication 92, Bureau of Sport Fisheries and Wildlife, U.S. Fish and Wildlife
  20. 20. Permanent Ponds (Class V)
  21. 21. Semi-permanent Ponds (Class IV)
  22. 22. Seasonal Ponds (Class III)
  23. 23. Temporary Ponds (Class II)
  24. 24. Ephemeral Ponds (Class 1)
  25. 25. Relationship Between # Mallard Pairs/Ha of Wetland and Individual Wetland Size (in Ha) 1 0.9 Mallard Pairs/Ha 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0 1 2 3 4 5 6 Wetland Size (in Ha) Wetland Area = 10 Ha Wetland Area = 10 Ha Wetland Area = 10 Ha One 10 Ha wetland = 1 Mallard Pair Ten 1 Ha wetlands = 3 Mallard Pairs One Hundred 0.1 Ha wetlands = 9 Mallard Pairs Source: Reynolds, R.E., D.R. Cohan, and M.A. Johnson. 1996. Using landscape information approaches to increase duck recruitment in the Prairie Pothole Region. Trans. N. Amer. Wildl. And Nat. Resour. Conf.
  26. 26. Wetland Offset Challenges 1. Equivalency – Variability – Clear Objectives, Agreement on Currency
  27. 27. Wetland Values Water Quality  Nutrients  Chemicals  Sediments Water quantity  Flood prevention  Groundwater recharge GHG sequestration Recreation Biodiversity
  28. 28. Hydrologic Response To Draining Wetlands current drainage area boundary wetlands stream
  29. 29. Hydrologic Response To Draining Wetlands
  30. 30. Hydrologic Response To Draining Wetlands New drainage area boundary
  31. 31. Wetland Offset Challenges 1. Equivalency – Variability – Clear Objectives, Agreement on currency 2. Proximity – Benefits accrue at different scales
  32. 32. Wetland Restoration vs. Securement A) Fall 2008 B) Spring 2009 C) Fall 2011
  33. 33. Wetland Offset Challenges 1. Equivalency – Variability – Clear Objectives, Agreement on currency 2. Proximity – Benefits accrue at different scales 3. Timing – Benefits accrue at different rates 4. Additionality – Expected rates of loss
  34. 34. Offset rules cabaysdirt works.com
  35. 35. Wetland Offset Challenges 1. Equivalency – Variability – Clear Objectives, Agreement on currency 2. Proximity – Benefits accrue at different scales 3. Timing – Benefits accrue at different rates 4. Additionality – Expected rates of loss 5. Equitability
  36. 36. Wetland Offset Challenges 1. Equivalency – Variability – Clear Objectives, Agreement on currency 2. Proximity – Benefits accrue at different scales 3. Timing – Benefits accrue at different rates 4. Additionality – Expected rates of loss 5. Equitability 6. Lack of wetland inventory/monitoring
  37. 37. Atlantic Province Offset Similarities NB, NS and PEI:  Wetland and Watercourse Alteration Regulation  Mitigation Sequence in place  Ratios established  NB 2:1, NS 2:1, PE 3:1
  38. 38. Alberta Offset rules  Mitigation Sequence in place  Variable Ratios  Within same watershed
  39. 39. Wetland Offset Challenges 1. Equivalency – Variability – Clear Objectives, Agreement on currency 2. Proximity – Benefits accrue at different scales 3. Timing – Benefits accrue at different rates 4. Additionality – Expected rates of loss 5. Equitability 6. Lack of wetland inventory/monitoring 7. Finding a qualified delivery agent!
  40. 40. Delivery Agent      Identify suitable projects Manage and maintain projects as required Provide long-term security Monitor projects Provide effective and efficient process
  41. 41. Ducks Unlimited Canada, a private, non-profit charitable organization, conserves, restores and manages wetlands and associated habitat for North America’s waterfowl. These habitats also benefit other wildlife and people.

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