![]() Conclusionsįire was far more frequent historically than currently. Lightning was not frequent but could likely have been sufficient to ignite fires that could spread readily given the rolling terrain and long fire season. Fires were historically frequent, occurring on average every 5 to 8 years at most sites. Forests covered 12% of the ecotone and these are still mostly forest. The 16% of the landscape that was pine savanna is now forest or shrubs, agriculture, perennial vegetation under the Conservation Reserve Program, or developed no savanna now exists. More than half of the ecotone area was prairie, which is now dominated by agriculture, with some residential development. ![]() Historically, the ecotone was a matrix of prairie with extensive savanna and some forest. We used fire and lightning records from 1992 to 2015 to interpret the role of people and lightning. We reconstructed historical fire occurrence (1650 to 1900) from fire-scarred trees. We combined LANDFIRE Existing Vegetation classes to contrast historical land cover with current land cover. We used General Land Office survey field notes about the occurrence of bearing trees to locate historical (1870s to 1880s) prairie, pine savanna, and forest at the eastern edge of the bioregion. Our objective was to understand how historical and current fire occurrences and human development influenced the Palouse Prairie–forest ecotone. While these ecotones cover small areas, their sharp gradients in land cover promote rich ecological interaction and high conservation value. The current expansion of pine plantations and subsequent invasions acting synergistically with climate warming and increased human ignitions warrant a highly vulnerable landscape in the near future for northwestern Patagonia if no management actions are undertaken.Prairie–forest ecotones are ecologically important for biodiversity and ecological processes. Pruning of basal branches in plantations may substantially reduce fire hazard by lowering the probability of fire crowning, and mechanical removal of invasion seems effective in restoring original fuel structure in the native community. These changes in fuel properties have the potential to affect fire behavior, increasing fire intensity by almost 30 times. We found that pine plantations and their subsequent invasion in the Patagonian shrubby steppe produced sharp changes in fine fuel amount and its vertical and horizontal continuity. In the forest-steppe ecotone of northwestern Patagonia, we evaluated fine fuels structure and simulated fire behavior in the native shrubby steppe, pine plantations, pine invasions, and mechanically removed invasions to establish the relative ecological vulnerability of these forestry and invasion scenarios to fire. However, studies evaluating alterations in flammability caused by pines in Patagonia are scarce. In several regions of the southern hemisphere, exotic pines have been extensively planted in native treeless areas for forestry purposes and have subsequently invaded the native environments. Such changes are not easily predicted and deserve system-specific studies. Planted and invading non-native plant species can alter fire regimes through changes in fuel loads and in the structure and continuity of fuels, potentially modifying the flammability of native plant communities. Pine plantations and invasion alter fuel structure and potential fire behavior in a Patagonian forest-steppe ecotone Paritsis J.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |