Table 4.
Annual N fixation within alder shrublands and alder savannas. Rates from this tundra ecosystem are at the lower end of the range reported for alder N fixation in boreal regions.
| Study | Species | Biome/Habitat | Methods | Annual N fixation (g N/ m2/ yr) |
|---|---|---|---|---|
| This study | A. viridis spp. fruticosa | Tundra (Alder shrubland community) |
15N2 incubation of nodules Soil core collection for nodule biomass |
1.95 ± 0.68 |
| This study | A. viridis spp. fruticosa | Tundra (Alder savanna community) |
15N2 incubation of nodules Soil core collection for nodule biomass |
0.53 ± 0.19 |
| Mitchell and Ruess (2009) | A. viridis spp. fruticosa | Boreal (post-fire succession) | ARA incubation of nodules Soil core collection for nodule biomass |
0.25 - 0.66 |
| Uliassi and Ruess (2002) | Alnus incana spp. tenuifolia | Boreal (floodplain, unfertilized) | ARA incubation of nodules Soil core collection for nodule biomass |
3.9 - 8.8 |
| Ruess et al. (2009) | Alnus incana spp. tenuifolia | Boreal (alder stands impacted by canker) |
15N2 incubation of nodules Soil core collection for nodule biomass |
2.2 - 10.7 |
| Ruess et al. (2013) | Alnus incana spp. tenuifolia | Boreal (floodplain, unfertilized) |
15N2 incubation of nodules Soil core collection for nodule biomass |
2.6 - 3.8 |
| Crocker and Major (1955) | Alnus viridis spp. crispa | Boreal (recently deglaciated area) | Annual N increment in soil 40 year period |
6.2 |
| Van Cleve et al. (1971) | Alnus incana spp. tenuifolia | Boreal (floodplain, unfertilized) | Annual N increment in soil 20 year period |
15.6 |