This document discusses wetlands and challenges with biodiversity offsets. It begins by defining wetlands and describing Canada's five main wetland classes: bogs, fens, swamps, marshes, and shallow open waters. It then discusses key challenges with wetland offsets, including issues with equivalency between impacted and offset wetlands, the scale at which wetland benefits accrue, differences in how quickly benefits develop, and ensuring offsets are additional to what would occur anyway. The document also provides examples of wetland offset policies from Atlantic Canada and Alberta, and notes that finding an appropriate organization to deliver offset projects can be a challenge.
Wetlands: Biodiversity Offsets: Challenges and considerations
1. Wetlands:
Biodiversity Offsets: Challenges and
considerations
Wetlands:
David Howerter & Karla Guyn, Ducks Unlimited Canada
ecology of prairie wetlands and their
importance to waterfowl
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. Canada’s Wetlands
• there are five classes
of wetlands in the
Canadian Wetland
Classification System:
bogs, fens, swamps,
marshes, & shallow
water wetlands
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
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. Canada’s Wetlands
• organic wetlands (> 40 cm of peat):
- bogs
- fens
peatlands
• mineral wetlands:
- swamps
- marshes
- shallow open water
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
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
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. Canada has approx. 127 million ha of
wetlands (24% of all the world’s
wetlands)
20. 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
26. 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.
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
37. 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
38. 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
39.
40. Alberta Offset rules
Mitigation Sequence in place
Variable Ratios
Within same watershed
41. 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!
42. Delivery Agent
Identify suitable projects
Manage and maintain projects as required
Provide long-term security
Monitor projects
Provide effective and efficient process
43. 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.