Table 4. Cutthroat trout habitat amounts relative to rainbow trout range.
| Inside range of rainbow trout | Outside range of rainbow trout | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Scenarioa | PRTA | Length | % change | Volume | % change | Length | % change | Volume | % change |
| Current | <1% | 7,869 | — | 1,656 | — | 16,186 | — | 4,117 | — |
| <10% | 9,863 | — | 2,854 | — | 21,760 | — | 7,925 | — | |
| <20% | 10,887 | — | 3,394 | — | 23,290 | — | 9,051 | — | |
| Equilibrium | <1% | 7,869 | — | 1,656 | — | 9,472 | -41.5% | 2,070 | -49.7% |
| <10% | 9,863 | — | 2,854 | — | 13,643 | -37.3% | 4,479 | -43.5% | |
| <20% | 10,887 | — | 3,394 | — | 16,588 | -28.8% | 5,922 | -34.6% | |
| Current + 0.5°C | <1% | 6,302 | -19.9% | 1,245 | -24.8% | 13,855 | -14.8% | 116,017 | -18.8% |
| <10% | 8,121 | -17.7% | 2,099 | -26.5% | 19,391 | -10.2% | 227,997 | -16.0% | |
| <20% | 9,339 | -14.2% | 2,582 | -23.9% | 20,882 | -9.5% | 264,298 | -14.6% | |
| Equilibrium + 0.5°C | <1% | 6,302 | — | 1,245 | — | 7,163 | -55.7% | 1,495 | -63.7% |
| <10% | 8,121 | — | 2,099 | — | 11,110 | -48.9% | 3,402 | -57.1% | |
| <20% | 9,339 | — | 2,582 | — | 13,855 | -40.5% | 4,711 | -47.9% | |
| Current + 1.0°C | <1% | 4,962 | -36.9% | 911 | -45.0% | 11,240 | -30.6% | 2,620 | -36.4% |
| <10% | 6,723 | -31.8% | 1,615 | -43.4% | 17,165 | -21.1% | 5,506 | -30.5% | |
| <20% | 7,820 | -28.2% | 1,982 | -41.6% | 18,746 | -19.5% | 6,438 | -28.9% | |
| Equilibrium + 1.0°C | <1% | 4,962 | — | 911 | — | 5,122 | -68.4% | 1,043 | -74.7% |
| <10% | 6,723 | — | 1,615 | — | 8,455 | -61.1% | 2,475 | -68.8% | |
| <20% | 7,820 | — | 1,982 | — | 11,038 | -52.6% | 3,546 | -60.8% | |
Length (km) and volume (m3) of stream habitat inside and outside the historical range of rainbow trout predicted to host cutthroat trout populations with admixture below specified thresholds of the percentage of rainbow trout alleles (PRTA) at a site for the 55,234-km study area network. Estimates were obtained by applying the final predictive models to the covariates associated with each reach in the stream network.
aGeological barriers and non-native brook trout exclude cutthroat trout from some streams within the study area so estimates of habitat amount are optimistic, although barriers may preclude rainbow trout access in some streams. The estimates are also predicated on no changes in propagule pressure from rainbow trout, although this could be altered by stocking practices.