CFE agenda 100917 - Laserfiche WebLink

Browse Search

Northern hardwood forests in lower mountain ranges could be eliminated if their zone shifts upward too far. Those in higher ranges are unlikely to be eliminated, but their extent will become more limited. Loss of lower elevation portions of patches will increase fragmentation to some degree. Some patches that now are connected may become isolated if the lower elevation limit rises. Patches in different mountain ranges are already naturally isolated by the warmer climate at lower elevations. These communities were presumably shifted upward in elevation during the Hypsithermal period, and those on lower ranges may have been eliminated then. There is likely to be little additional wholesale loss of communities or species until the climate becomes warmer than the Hypsithermal. The Hypsithermal was drier as well as warmer, and if our future climate is not drier, the change may be less. However, having more severe drought and increased fire frequency may be sufficient to cause substantial changes even if the average rainfall does not change. Effects of reduced area and fragmentation may be significant, reducing some species populations enough to cause demographic problems. Because the current area is limited, some species populations are likely already small enough to be close to demographic problems. Habitat Level Effects: Natural Communities: Third Approximation Name: Comments: Boulderfield Forest Tied to distinctive sites, these communities will generally not be able to migrate at all. A few new examples may develop, where bouldery sites are currently covered with spruce -fir, as at Grandfather Mountain. The distinctive boulderfield environment is occupied by the Boulderfield Subtype of Rich Cove Forest at lower elevations, and this community will spread into some of the lower elevation Boulderfield Forests. Some Boulderfield Forests have substantial seepage. Droughts may be a threat to seepage and disrupt the water- dependent component of the community. Northern Hardwood Forest (Beech Gap Subtype) Tied to distinctive microsites -- either high elevation gaps or high elevation peaks that might otherwise have spruce -fir. Both may be particularly vulnerable to warming climate. The most likely community to develop in their place would be typic Northern Hardwood Forest. Northern Hardwood Forest (Typic Subtype) Usually occurs in large patches. Patches will likely migrate uphill and shrink but most are unlikely to be eliminated. Appendix B 177