| The Appalachian Mountains are home to remarkable diversity compared to other temperate climates. Paleoecological and contemporary ecological and biogeographical investigations have contributed considerably to our understanding of vegetative adaptation to climate change over geologic time and today. Some of these investigations have pointed to intrinsic characteristics of the mountains that helped plant species adapt to change over geologic time scales. In this dissertation, the geography of Appalachian forests is reviewed (Chapter 1) and the role of topography in supporting migratory adaptation is explained, qualitatively and quantitatively (Chapter 2). Geographic factors supporting dispersal, establishment, and regeneration are combined and analyzed using a network approach to identify critical habitat pathways for plant migration (Chapter 3). Forest fire regimes under historical and future climate conditions are analyzed and vegetation and carbon storage effects are evaluated (Chapter 4). The preponderance of the evidence presented here support the conclusion that, at large spatial extents, long temporal scales, and high biotic levels, Appalachian forests are relatively resilient to the scope of stressors anticipated in the coming century, although interactions between stressors can not be ruled out (Chapter 5). The predicted degree of temperature and precipitation in this region will have very noticeable effects on species composition and ecosystem processes, but this research highlights aspects of the Appalachians that support adaptation to climatic change. The complex topography provides a high diversity of microclimates that can support biodiversity through global warming and with small investments in land conservation to improve connectivity natural migratory adaptation may be successful in many places. This research predicts an increase in wildfire frequency and extent, with a consequent decrease in severity. These shifts in fire regimes have the potential to lower carbon storage and change species dominance slowly by selecting more fire-adapted species. |
