Subalpine Larch
A visual comparison of Little’s range map shows that the projection of the bioclimatic model overestimates the distribution of subalpine larch in the western portion of southwestern British Columbia and portions of the central Rocky Mountains (Figure 1A). Error associated with Canadian projections may have been exasperated due to the lack of species presence-absences data for that region. Nonetheless, the model does an excellent job of predicting the United States distributions. Here the majority of the pixels receiving the greatest proportion of votes occur well within the range limits.
Mapped projections for the effect of global warming on distribution of subalpine larch’s realized climatic niche space in decades 2030 (Figure 1B), 2060 (Figure 1C) and 2090 (Figure 1D) indicate a rapid decline in distribution (Table: Projected change in area of species). For area studied, about 62 percent of the contemporary realized climatic niche space is projected to disappear by the end of decade 2030 (Table: Projected change in area of species). Only about one-third of the remaining proportion is expected to occur in pixels suitable for the species today. By decade 2030, the mean elevation of the realized climatic niche space is projected to occur 100 m higher in altitude whereas the minimum elevation is expected to rise almost 300 m by the end of the century. Also, by the end of the century, only 3 percent of the contemporary realized climatic niche space is expected to remain and should be relegated to a few high mountain peaks in south-central Idaho, southwestern Montana, the northern Cascade Range in Washington and to the Grand Teton Range in northwestern Wyoming. Note that suitable climate space in the Grand Teton Range is projected to first occur in decade 2030 and persist in decades 2060 and 2090.
Encyclopedia ID: p3668
