Evidence Platform
Assisted migration to address climate change: Recommendations for aspen reforestation in western Canada
Gray L. K. et al., 2011. Ecological Applications
Original research (primary data)View External Publication Link
Abstract
Human-aided movement of species populations in large-scale reforestation programs could be a potent and cost-effective climate change adaptation strategy. Such large- scale management interventions, however, tend to entail the risks of unintended consequences, and we propose that three conditions should be met before implementing assisted migration in reforestation programs: (1) evidence of a climate-related adaptational lag, (2) observed biological impacts, and (3) robust model projections to target assisted migration efforts. In a case study of aspen (Populus tremuloides Michaux.) we use reciprocal transplant experiments to study adaptation of tree populations to local environments. Second, we monitor natural aspen populations using the MODIS enhanced vegetation index as a proxy for forest health and productivity. Last, we report results from bioclimate envelope models that predict suitable habitat for locally adapted genotypes under observed and predicted climate change. The combined results support assisted migration prescriptions and indicate that the risk of inaction likely exceeds the risk associated with changing established management practices. However, uncertainty in model projections also implies that we are restricted to a relatively short 20-year planning horizon for prescribing seed movement in reforestation programs. We believe that this study exemplifies a safe and realistic climate change adaptation strategy based on multiple sources of information and some understanding of the uncertainty associated with recommendations for assisted migration. Ad hoc migration prescriptions without a similar level of supporting information should be avoided in reforestation programs.
Case studies
Basic information
- Case ID: INT-234-5
- Intervention type: Management
- Intervention description:
assisted migration: population movement within a species range or somewhat beyond the leading edge... apply to common and wide- spread species for the purpose of maintaining ecosystem health and productivity Test assisted migration through reciprocal transplant experiments...Three to 11 bulked commercial seed lots from collection locations in the broad vicinity of each test site were grown in a forest nursery in 1997, and seedlings representing a total of 38 provenances (seed lots) were planted at all five test locations in the spring of 1998. At each test site, provenances were planted in a randomized complete block design with six replications in five-tree row plots.
- Landscape/sea scape ecosystem management: Yes
-
Climate change impacts Effect of Nbs on CCI Effect measures Loss of timber production Negative Difference in tree height (%) of the transplanted provenance compared to local provenance - Approach implemented in the field: Yes
- Specific location:
northern boreal plains of alberta (568460 N, 1178380 W)
- Country: Canada
- Habitat/Biome type: Boreal forests and taiga |
- Issue specific term: Not applicable
Evidence
- Notes on intervention effectivness: effectiveness assessment: we calculated a matrix of probabilities that provenances transferred from different ecoregions (representing assisted migration) matched or exceeded the growth of provenances collected near the test site (representing local genotypes). --> therefore the growth of the local genotypes is a valid comparator of what would be without the intervention Here, a southward transfer from the region is clearly disadvan- tageous, but a northward transfer to the region is unlikely to have a benefit. --> all translocations performed worse than the local provenance therefore negative effect
- Is the assessment original?: Yes
- Broadtype of intervention considered: Not applicable
- Compare effectivness?: No
- Compared to the non-NBS approach: Not applicable
- Report greenhouse gas mitigation?: No
- Impacts on GHG: Not applicable
- Assess outcomes of the intervention on natural ecosystems: Yes
- Impacts for the ecosystem: Negative
- Ecosystem measures: same outcome measures as for the climate impact outcomes: aspen tree height
- Assess outcomes of the intervention on people: No
- Impacts for people: Not reported
- People measures:
- Considers economic costs: No
- Economic appraisal conducted: No
- Economic appraisal described:
- Economic costs of alternative considered: No
- Compared to an alternative: Not reported
Evaluation methodology
- Type of data: Quantitative
- Is it experimental: Yes
- Experimental evalution done: In-situ/field
- Non-experimental evalution done: Not applicable
- Study is systematic:
Basic information
- Case ID: INT-234-4
- Intervention type: Management
- Intervention description:
assisted migration: population movement within a species range or somewhat beyond the leading edge... apply to common and wide- spread species for the purpose of maintaining ecosystem health and productivity Test assisted migration through reciprocal transplant experiments...Three to 11 bulked commercial seed lots from collection locations in the broad vicinity of each test site were grown in a forest nursery in 1997, and seedlings representing a total of 38 provenances (seed lots) were planted at all five test locations in the spring of 1998. At each test site, provenances were planted in a randomized complete block design with six replications in five-tree row plots.
- Landscape/sea scape ecosystem management: Yes
-
Climate change impacts Effect of Nbs on CCI Effect measures Loss of timber production Unclear results Difference in tree height (%) of the transplanted provenance compared to local provenance - Approach implemented in the field: Yes
- Specific location:
southern boreal plains of Saskatchewan (538260 N, 1058350 W)
- Country: Canada
- Habitat/Biome type: Boreal forests and taiga |
- Issue specific term: Not applicable
Evidence
- Notes on intervention effectivness: effectiveness assessment: we calculated a matrix of probabilities that provenances transferred from different ecoregions (representing assisted migration) matched or exceeded the growth of provenances collected near the test site (representing local genotypes). --> therefore the growth of the local genotypes is a valid comparator of what would be without the intervention "All other probability values are intermediate, indicating either a minor transfer effect size or uncertainty due to low sample sizes." --> no conclusions made and perhaps limited because of sample size and therefore coded as 'unclear'
- Is the assessment original?: Yes
- Broadtype of intervention considered: Not applicable
- Compare effectivness?: No
- Compared to the non-NBS approach: Not applicable
- Report greenhouse gas mitigation?: No
- Impacts on GHG: Not applicable
- Assess outcomes of the intervention on natural ecosystems: Yes
- Impacts for the ecosystem: Unclear
- Ecosystem measures: same outcome measures as for the climate impact outcomes: aspen tree height
- Assess outcomes of the intervention on people: No
- Impacts for people: Not reported
- People measures:
- Considers economic costs: No
- Economic appraisal conducted: No
- Economic appraisal described:
- Economic costs of alternative considered: No
- Compared to an alternative: Not reported
Evaluation methodology
- Type of data: Quantitative
- Is it experimental: Yes
- Experimental evalution done: In-situ/field
- Non-experimental evalution done: Not applicable
- Study is systematic:
Basic information
- Case ID: INT-234-3
- Intervention type: Management
- Intervention description:
assisted migration: population movement within a species range or somewhat beyond the leading edge... apply to common and wide- spread species for the purpose of maintaining ecosystem health and productivity Test assisted migration through reciprocal transplant experiments...Three to 11 bulked commercial seed lots from collection locations in the broad vicinity of each test site were grown in a forest nursery in 1997, and seedlings representing a total of 38 provenances (seed lots) were planted at all five test locations in the spring of 1998. At each test site, provenances were planted in a randomized complete block design with six replications in five-tree row plots.
- Landscape/sea scape ecosystem management: Yes
-
Climate change impacts Effect of Nbs on CCI Effect measures Loss of timber production Positive Difference in tree height (%) of the transplanted provenance compared to local provenance - Approach implemented in the field: Yes
- Specific location:
Taiga plains of British Columbia (588340 N, 1228220 W)
- Country: Canada
- Habitat/Biome type: Boreal forests and taiga |
- Issue specific term: Not applicable
Evidence
- Notes on intervention effectivness: effectiveness assessment: we calculated a matrix of probabilities that provenances transferred from different ecoregions (representing assisted migration) matched or exceeded the growth of provenances collected near the test site (representing local genotypes). --> therefore the growth of the local genotypes is a valid comparator of what would be without the intervention The probabilities of matching or increasing productivity relative to local sources are very pronounced for movement to and from the most northern region (Taiga, Site 70), with northward transfer very likely to be beneficial and southward movements certain to be disadvantageous. --> provenances from all other sites out-performed the growth of the local taiga provenance
- Is the assessment original?: Yes
- Broadtype of intervention considered: Not applicable
- Compare effectivness?: No
- Compared to the non-NBS approach: Not applicable
- Report greenhouse gas mitigation?: No
- Impacts on GHG: Not applicable
- Assess outcomes of the intervention on natural ecosystems: Yes
- Impacts for the ecosystem: Positive
- Ecosystem measures: same outcome measures as for the climate impact outcomes: aspen tree height
- Assess outcomes of the intervention on people: No
- Impacts for people: Not reported
- People measures:
- Considers economic costs: No
- Economic appraisal conducted: No
- Economic appraisal described:
- Economic costs of alternative considered: No
- Compared to an alternative: Not reported
Evaluation methodology
- Type of data: Quantitative
- Is it experimental: Yes
- Experimental evalution done: In-situ/field
- Non-experimental evalution done: Not applicable
- Study is systematic:
Basic information
- Case ID: INT-234-2
- Intervention type: Management
- Intervention description:
assisted migration: population movement within a species range or somewhat beyond the leading edge... apply to common and wide- spread species for the purpose of maintaining ecosystem health and productivity Test assisted migration through reciprocal transplant experiments...Three to 11 bulked commercial seed lots from collection locations in the broad vicinity of each test site were grown in a forest nursery in 1997, and seedlings representing a total of 38 provenances (seed lots) were planted at all five test locations in the spring of 1998. At each test site, provenances were planted in a randomized complete block design with six replications in five-tree row plots.
- Landscape/sea scape ecosystem management: Yes
-
Climate change impacts Effect of Nbs on CCI Effect measures Loss of timber production Positive Difference in tree height (%) of the transplanted provenance compared to local provenance - Approach implemented in the field: Yes
- Specific location:
the southern boreal plains of Alberta (548450 N, 1138100 W)
- Country: Canada
- Habitat/Biome type: Boreal forests and taiga |
- Issue specific term: Not applicable
Evidence
- Notes on intervention effectivness: effectiveness assessment: we calculated a matrix of probabilities that provenances transferred from different ecoregions (representing assisted migration) matched or exceeded the growth of provenances collected near the test site (representing local genotypes). --> therefore the growth of the local genotypes is a valid comparator of what would be without the intervention "Smaller positive effects associated with a high probability include ... and transfers from Saskatchewan to Alberta." --> all transfers don't produce positive results (some perform worse than the local provenance) but what matters is one of the transfers was positive and therefore the intervention could be effective at this site if the correct provenance is chosen (in this case, those from the sask boreal plains)
- Is the assessment original?: Yes
- Broadtype of intervention considered: Not applicable
- Compare effectivness?: No
- Compared to the non-NBS approach: Not applicable
- Report greenhouse gas mitigation?: No
- Impacts on GHG: Not applicable
- Assess outcomes of the intervention on natural ecosystems: Yes
- Impacts for the ecosystem: Positive
- Ecosystem measures: same outcome measures as for the climate impact outcomes: aspen tree height
- Assess outcomes of the intervention on people: No
- Impacts for people: Not reported
- People measures:
- Considers economic costs: No
- Economic appraisal conducted: No
- Economic appraisal described:
- Economic costs of alternative considered: No
- Compared to an alternative: Not reported
Evaluation methodology
- Type of data: Quantitative
- Is it experimental: Yes
- Experimental evalution done: In-situ/field
- Non-experimental evalution done: Not applicable
- Study is systematic:
Basic information
- Case ID: INT-234-1
- Intervention type: Management
- Intervention description:
assisted migration: population movement within a species range or somewhat beyond the leading edge... apply to common and wide- spread species for the purpose of maintaining ecosystem health and productivity Test assisted migration through reciprocal transplant experiments...Three to 11 bulked commercial seed lots from collection locations in the broad vicinity of each test site were grown in a forest nursery in 1997, and seedlings representing a total of 38 provenances (seed lots) were planted at all five test locations in the spring of 1998. At each test site, provenances were planted in a randomized complete block design with six replications in five-tree row plots.
- Landscape/sea scape ecosystem management: Yes
-
Climate change impacts Effect of Nbs on CCI Effect measures Loss of timber production Positive Difference in tree height (%) of the transplanted provenance compared to local provenance - Approach implemented in the field: Yes
- Specific location:
eastern Rocky Mountain foothills (test site coordinates, 528500 N, 1148530 W)
- Country: Canada
- Habitat/Biome type: Temperate forests |
- Issue specific term: Not applicable
Evidence
- Notes on intervention effectivness: effectiveness assessment: we calculated a matrix of probabilities that provenances transferred from different ecoregions (representing assisted migration) matched or exceeded the growth of provenances collected near the test site (representing local genotypes). --> therefore the growth of the local genotypes is a valid comparator of what would be without the intervention "Smaller positive effects associated with a high probability include transfers from the Boreal Plains to the Foothills" --> all transfers don't produce positive results (some perform worse than the local provenance) but what matters is one of the transfers was positive and therefore the intervention could be effective at this site if the correct provenance is chosen (in this case, those from the boreal plains)
- Is the assessment original?: Yes
- Broadtype of intervention considered: Not applicable
- Compare effectivness?: No
- Compared to the non-NBS approach: Not applicable
- Report greenhouse gas mitigation?: No
- Impacts on GHG: Not applicable
- Assess outcomes of the intervention on natural ecosystems: Yes
- Impacts for the ecosystem: Positive
- Ecosystem measures: same outcome measures as for the climate impact outcomes: aspen tree height
- Assess outcomes of the intervention on people: No
- Impacts for people: Not reported
- People measures:
- Considers economic costs: No
- Economic appraisal conducted: No
- Economic appraisal described:
- Economic costs of alternative considered: No
- Compared to an alternative: Not reported
Evaluation methodology
- Type of data: Quantitative
- Is it experimental: Yes
- Experimental evalution done: In-situ/field
- Non-experimental evalution done: Not applicable
- Study is systematic: