Bob Jamieson, BioQuest International Consulting Ltd. Contact Information:
Bob Jamieson
Box 73, Ta Ta Creek, BC V0B 2H0
Phone: 250-422-3322
Email: bjamieson@cintek.com
Floodplain ecosystems, dominated by Black Cottonwood, historically were much more extensive in the upper Columbia Basin than they are today. These ecosystems have been heavily impacted by impoundment, flow regulation, cattle grazing, clearing for agriculture and human settlement. The talk gave an overview of riparian cottonwood ecology in the Basin and identified the critical ecological functions within these systems. We also provided an overview of the values, for both fish and wildlife, associated with these ecosystems. The recruitment strategy of black cottonwood is based on the release of very large numbers of very small seeds with minimal resources for initial establishment and growth. They therefore require a moist seeding environment. This environment is provided by point bars along major rivers as the spring freshette recedes. As a result, Black Cottonwood depends on the spring freshette to provide conditions for recruitment of new seedlings. Where freshette no longer occurs due to the presence of dams and flow regulation on the system, recruitment is curtailed. Mary Louise Polzin, in recent work on the Kootenay River, found abundant cottonwood recruitment in 1996 and 1997, producing mean seedling densities of 536, and 142 seedlings/m2 along the Upper Kootenay and Fisher Rivers. Both of these are free-flowing rivers. In marked contrast, no seedlings were established on similar sites along the Lower Kootenay River, downstream from the Libby Dam. Flow regulation is a major factor affecting the long term survival of these ecosystems, as the life history and ecology of cottonwoods and other riverine organisms are dependent upon dynamic flow regimes. In other jurisdictions, work is now underway using artificial flow releases to mimic natural conditions and allow recruitment of cottonwoods along river reaches below dams. These naturalized flows have been also shown to benefit critical fish and wildlife species with minimal economic cost to dam operators since recruitment flows are not necessary in all years but can be provided during high snowpack years. We are undertaking a study of riparian ecosystems in the Columbia Basin, focusing initially on the Upper Kootenay (above Kootenay Lake) and Yakima drainages. Funding has been provided by Bonneville Power Administration to work in both the Canadian and American portions of the Basin with the long term objective of: - documenting the status of these systems throughout the Basin,
- documenting the need for management concern directed at these systems and;
- identifying practical alternatives for maintaining these systems in a 100-200 year time horizon, primarily through modified flow regimes.
This work is being carried out by an international team with expertise from four Universities (3 American and 1 Canadian), in partnership with several related projects concerned with related riparian and stream flow issues. IN THE PRESENTATION WE ATTEMPTED TO ANSWER THE FOLLOWING QUESTIONS: WHAT ARE FLOODPLAIN RIPARIAN ECOSYSTEMS? Riparian floodplain areas dominated by deciduous trees, are a unique and important ecosystem. We haven't spent much time thinking about them, since we don't harvest timber in these systems. In the East Kootenay floodplain deciduous ecosystems are dominated by black cottonwood, aspen, birch, hawthorn and river alder; with a white spruce and Douglas fir component in some areas. These areas are in permanent dis-climax due to channel changes and annual flooding. They are a dominant feature in Rocky Mtn Trench on the Upper Columbia and Upper Kootenay. They are less obvious in the West Kootenays due to topography and reservoir flooding. In the American portion of the Basin cottonwood stands are often the only large tree type found along rivers in the drier portions of the Basin. WHAT IS THE ROLE OF BLACK COTTONWOOD IN THESE ECOSYSTEMS? Cottonwoods are a dominant feature critical to fish and wildlife in these areas. They are large and are generally located right on the river bank. They can survive flooding for 1-2 months. They provide a range of ecological services that are critical to riverine and riparian health. WHY DO NEED TO BE CONCERNED ABOUT THESE ECOSYSTEMS? Native cottonwoods provide critical habitat and support high levels of biodiversity within riparian corridors (Finch and Ruggerro 1993, Dunstone and Gorman 1998, Whitham et al. 1996). They enhance the quality of aquatic habitats by moderating water temperatures (Debano and Schmidt 1990), and supplying carbon, nutrients and large woody debris that provide habitat and sustenance for a variety of instream and streamside invertebrates important to fish diets. Cottonwood forests are commonly associated with major salmon spawning redds, while also providing important habitat for resident and migrating songbirds (Martinsen and Whitham 1994, Whitham et al. 1996). Recent research by the Canadian Wildlife Service and others have found that these habitats are critical for songbirds as resting and feeding areas during migration (R. Millikin, pers. comm.). The Pileated woodpecker is an important cavity excavator in these systems (Ohanjanian 1991), using large black cottonwood trees and snags for nesting. Their abandoned cavities are used by other cavity-nesters, such as waterfowl (wood ducks, mergansers, golden eye), flying squirrels and several species of bats (Dunstone and Gorman 1998). These systems are also important for otter, beaver, ruffed grouse, great blue heron (rookery sites), osprey, owls, bald eagle, golden eagle and peregrine falcon during migration. Riparian cottonwood ecosystems also play an important role in the structure and function of riverine habitats. Quigley and Arbelbide (1997) among others have noted that riparian cottonwoods: 1. Dissipate stream energy associated with peak flows, stabilize riverbanks, reduce erosion and improve water quality (Debano and Schmidt 1990, Strahler and Strahler 1973);
2. Filter sediment, capture bedload and promote floodplain development;
3. Improve flood water retention and groundwater recharge,
4. Provide shade and reduce water temperatures which benefit a wide range of resident and anadromous fish (Debano and Schmidt 1990).
5. Promote a diverse mosaic of ponds and river channel habitats that are necessary for fish production, waterfowl breeding and other wildlife uses, and
6. Support higher levels of biodiversity than streamside conifers (Naiman et al. 1992, Whitham et al. 1996).
These systems provide complexity, flowing and standing water, dead wood and cavities in productive, low elevation habitats that are moist through much of the year. As a result, extensive biological processes occurs which generates, among other things, extensive insect live through much of the spring, summer and fall seasons. WHAT ARE THE RISKS TO THESE SYSTEMS AS A RESULT OF HUMAN ACTIVITY? The major factors are: 1. Major flow regulating dams
2. Settlement
3. Agricultural use
4. Grazing
5. Water removals
6. Dyking
7. Evasive plants
8. Beaver activity
9. Harvest for Timber
We did not go into these issues in detail due to time limitations. WHAT IS THE DEGREE OF RISK TO THESE ECOSYSTEMS AS A RESULT OF HUMAN ACTIVITY? Several studies from across western North America have revealed the steady decline of extent and health of riparian cottonwood ecosystems (Rood and Mahoney 1990; Bradley et al. 1991, Braatne et al. 1996, Mahoney 1996). The primary causes of these declines have been woodland clearing and impacts due to water diversions and damming (Braatne et al. 1996). Research has shown that declines in riparian cottonwoods are caused primarily by the suppression of seedling recruitment. Since cottonwoods are a relatively short-lived tree (100-200 years), declines in recruitment over the past century have lead to the widespread loss of riparian cottonwood ecosystems. A major review of riparian ecosystems within the Interior Columbia Basin was recently completed by Manning and his colleagues (1998) that concludes … that "flooding disturbance has been virtually eliminated" … that "mid-seral stages have increased substantially". Further, the "….lack of recruitment by early seral riparian species and the senescence of larger, old trees in late seral riparian woodlands" were emphasized as a significant long-term problem requiring systematic evaluation. As a result, riparian ecosystems have been identified as a high priority in the 1994 Columbia Basin Fish and Wildlife Program (US side). Riparian cottonwoods represent one of the most critical ecosystems affected by dam construction and operation within the Canadian portion of the Columbia Basin (Jamieson and Ohanjanian 1995, Cooley and Jamieson 1997). These ecosystems support important ecological components that have not received the level of management concern that would be suggested by their rarity, degree of risk and their importance to ecosystem function in relation to both terrestrial and aquatic resources. Black Cottonwood systems have been identified as being of concern under Forest Practices Code in BC and are included in regional and provincial lists of habitat types at risk. WHY IS RECRUITMENT NOT OCCURRING? The recruitment strategy of black cottonwood is based on the release of very large numbers of very small seeds with minimal resources for initial establishment and growth. They therefore require a moist seeding environment with minimal competition. This environment is provided by point bars along major rivers as the spring freshette recedes. As a result, black cottonwood depends on the spring freshette to provide conditions for recruitment of new seedlings. Where freshette no longer occurs due to the presence of dams and flow regulation on the system, recruitment is curtailed. Mary Louise Polzin, in recent work on the Kootenay River, found abundant cottonwood recruitment in 1996 and 1997, producing mean seedling densities of 536, and 142 seedlings/m2 along the Upper Kootenay and Fisher Rivers. Both of these are free-flowing rivers. In marked contrast, no seedlings were established on similar sites along the Lower Kootenay River, downstream from the Libby Dam. This means that the stands of large cottonwood one sees at Creston, and other areas below large, flow regulating dams are likely at long term risk since no recruitment is occurring. In the presentation we provided a slide of the "recruitment box" which is a description of the flow pattern required for successful cottonwood seedling establishment. High water levels flood the recruitment sites on point bars and then, as the waters recede, they leave a moist seeding environment. After germination on these nursery sites, the roots of young seedlings must also keep pace with declining river levels (root growth averages 1.5 cm per day); Mahoney and Rood 1991, 1992, 1998, Selgelquist et al. 1993, Johnson 1994, Rood et al. 1995). If river levels decline too rapidly, young seedlings rapidly succumb to drought stress. A further problem is created where dams reduce summer baseflows and induce significant levels of drought stress among all age-classes, and thereby promote a decadent age- structure among local populations (Fenner et al. 1985, Bradley and Smith 1986, Rood and Mahoney 1990, Stomberg and Patten 1991, Scott et al. 1996). These older and larger cottonwood trees are also dependent on periodic flooding and recharging of the alluvial water table (Johnson and Jones 1977; Rood and Heinze-Milne 1989; Rood and Mahoney 1990; Snyder and Miller 1991; Stromberg and Patten 1992). RESTORATION: WHAT CAN WE DO? In recent years, researchers have successfully applied their knowledge of the life history and ecology of cottonwoods to promote natural patterns of recruitment below dams on several western rivers (Rood and Gourley 1996, Rood and Kalischuk 1998). In these cases, high water volumes available during "wet years" were released in a manner that was compatible with seed dispersal and establishment of cottonwood seedlings. These practices are now widely accepted and promoted by resource managers in Alberta (Mahoney 1997) and Nevada (Rood and Gourley 1996). Actual recruitment has been documented on the Truckee River as a result of these practices. WHERE DO WE NEED TO CONSIDER RESTORATION WORK? In the Canadian portion of the Basin this is a concern in the Revelstoke area below Revelstoke dam, in the Castlegar/Trail area, below Duncan dam and in the Creston area. There are much larger areas potentially at risk on the US side of the Kootenay River and in several other rivers in the Lower Columbia. Stands in the Creston Valley Wildlife Management Area are critical, as they are in the other areas mentioned. The retention and management of cottonwood stands on the free-flowing sections of the Columbia and Upper Kootenay are also important concerns. WHAT IS THE NATURE OF THE STUDY PRESENTLY UNDERWAY? We are involved in a major international study of this issue. The study is being lead by Bob Jamieson on the Canadian side and Dr. Jeff Braatne on the US side. We have established an Overview Committee to guide the project, made up of world class experts on riparian issues. Members of this committee are Dr. Jack Stanford, Dr. Stu Rood and Dr. Mike Mergliano. The field crew that will do field inventory of cottonwood stands is made up of Greg Allen, Dr. Clint Smyth, Mary Louise Polzin and students from the University of Lethbridge. The objectives of the study are: OBJECTIVE 1: Document the pre-dam status of riparian cottonwood stands in the Upper Kootenay and Yakima sub-basins.
OBJECTIVE 2: Document the present distribution (circa 1995) and status of riparian cottonwood stands in the Upper Kootenay and Yakima sub-basins.
OBJECTIVE 3: Test satellite data options for applicability for extrapolating from sample reaches to entire Upper Kootenay and Yakima sub-basins.
OBJECTIVE 4: Document stand health and recruitment to riparian cottonwood stands in the Upper Kootenay and Yakima sub-basins.
OBJECTIVE 5: Document the present flow regime in the Upper Kootenay and Yakima sub-basins.
OBJECTIVE 6: Document flow management options for maintaining riparian habitats in the Upper Kootenay and Yakima sub-basins.
OBJECTIVE 7: Document other management options for maintaining riparian habitats in the Upper Kootenay and Yakima sub-basins.
OBJECTIVE 8: Provide an overview of this issue and restoration options for the entire Columbia Basin, Canadian and US portions. The project will be accomplished through partnerships with: Bonneville Power Administration and Northwest Power Planning Council
Yakima Reaches Project
Flathead Lake Biological Station
University of Lethbridge, AB
University of Montana, Missoula
University of Washington, Seattle
The Ktunaxa Tribal Council will also be involved through data sharing and data processing through Eagle Vision Ltd. We will also work with related projects that include: Surgeon restoration programs on the Yakima River
Salmon restoration programs on the Yakima River
A Univeristy of Oregon project on riparian process and salmon
The Upper Kootenay Landowners' Riparian Stewardship Group.
A more detailed description of the project is available through Bob Jamieson at bjamieson@cintek.com (250-422-3322) LITERATURE CITED: All the literature cited in our project proposal is provided below as a potential resource for those attending the workshop. Baker, W.L. 1990. Climatic and Hydrologic Effects on the Regeneration of Populus angustifolia James along the Animas River, Colorado. J. of Biogeography 17: 59-73.
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Braatne J.H., S.B. Rood, and P.E. Heilman. 1996. Life history, ecology and conservation of riparian cottonwoods in North America. In: Biology of Populus and its implications for management and conservation, R.F Stettler, H.D. Bradshaw, Jr., P.E. Heilman
Braatne, J.H. 1997. Genetic structure of isolated populations of Plains Cottonwood (Populus deltoides var. occidentalis) along the lower Snake and Columbia Rivers. A report prepared for the US Forest Service and Boise Cascade Corporation. 44p.
Braatne, J.H., S.B. Rood, and R. Simons. 1998. Life history, ecology and distribution of riparian vegetation in the Hells Canyon Recreation Area. A detailed study plan prepared for the Idaho Power Company. 88p.
Braatne, J.H. 1998. Annual Review of the Joint BLM/USFS Black Cottonwood Restoration Program on the lower John Day River. Prepared for the US Forest Service and Bureau of Land Management, Prineville, Oregon. 33p.
Braatne, J.H. 1998. Annual Review of the Joint BLM/USFS Black Cottonwood Restoration Program on the lower John Day River. Prepared for the US Forest Service and Bureau of Land Management, Prineville, Oregon. 33p.
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Dunlap, J.M. and R.F. Stettler. 1998. Genetic variation and productivity of Populus trichocarpa and its hybrids. X. Trait correlations in young black cottonwood from four river valleys in Washington. Trees 13: 28-39.
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Lonard, R. I., F.W. Judd, J.H. Everitt, D.E. Escobar, M.R. Davis, M.N. Crawford and M.D. Desai. 1998 Monitoring Native Riparian Forest Vegetation: Color Infared film aids aerial change evaluation in the lower Rio Grande. EOM: 32-35.
McKay, S.J. 1997. The impact of river regulation on establishment processes of riparian black cottonwood. MSc. thesis, University of Washington, Seattle. 85 pp.
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Martinsen, G.D. and T.G. Whitham. 1994. More birds nest in hybrid cottonwood trees. Wilson Bull. 106:474-481.
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