Earth & Environmental Science Department, Lehigh University, Bethlehem, Pennsylvania, USA.
United States National Park Service Climate Change Response Program, Fort Collins, Colorado, USA.
Ecol Appl. 2023 Sep;33(6):e2901. doi: 10.1002/eap.2901. Epub 2023 Jul 2.
In fire-prone ecosystems, knowledge of vegetation-fire-climate relationships and the history of fire suppression and Indigenous cultural burning can inform discussions of how to use fire as a management tool, particularly as climate continues to change rapidly. On Wiisaakodewan-minis/Stockton Island in the Apostle Islands National Lakeshore of Wisconsin, USA, structural changes in a pine-dominated natural area containing a globally rare barrens community occurred after the cessation of cultural burning by the Indigenous Ojibwe people and the imposition of fire-suppression policies, leading to questions about the historical role of fire in this culturally and ecologically important area. To help understand better the ecological context needed to steward these pine forest and barrens communities, we developed palaeoecological records of vegetation, fire, and hydrological change using pollen, charcoal, and testate amoebae preserved in peat and sediment cores collected from bog and lagoon sediments within the pine-dominated landscape. Results indicated that fire has been an integral part of Stockton Island ecology for at least 6000 years. Logging in the early 1900s led to persistent changes in island vegetation, and post-logging fires of the 1920s and 1930s were anomalous in the context of the past millennium, likely reflecting more severe and/or extensive burning than in the past. Before that, the composition and structure of pine forest and barrens had changed little, perhaps due to regular low-severity surface fires, which may have occurred with a frequency consistent with Indigenous oral histories (~4-8 years). Higher severity fire episodes, indicated by large charcoal peaks above background levels in the records, occurred predominantly during droughts, suggesting that more frequent or more intense droughts in the future may increase fire frequency and severity. The persistence of pine forest and barrens vegetation through past periods of climatic change indicates considerable ecological resistance and resilience. Future persistence in the face of climate changes outside this historical range of variability may depend in part on returning fire to these systems.
在美国威斯康星州阿波斯特尔群岛国家湖滨区的 Wiisaakodewan-minis/Stockton 岛上，在印第安奥吉布瓦人停止文化燃烧和实施消防政策之后，一个以松树为主的自然区域发生了结构变化，其中包含一个全球罕见的荒地群落，这导致人们对火在这个具有文化和生态重要性的地区的历史作用产生了疑问。为了更好地了解管理这些松林和荒地群落所需的生态背景，我们利用花粉、木炭和从沼泽和泻湖沉积物中采集的泥炭和沉积物核心中保存的测试有孔虫，开发了植被、火灾和水文变化的古生态学记录。结果表明，火至少在 6000 年前就是 Stockton 岛生态的一个组成部分。20 世纪初的伐木导致了岛上植被的持续变化，而 20 世纪 20 年代和 30 年代的伐木火灾在过去一千年的背景下是异常的，可能反映了比过去更严重和/或更广泛的燃烧。在此之前，松林和荒地的组成和结构几乎没有变化，这可能是由于定期发生的低强度地表火灾所致，这些火灾可能以与印第安人口述历史一致的频率发生（约 4-8 年）。记录中背景水平以上的大木炭峰值表明，更高强度的火灾事件主要发生在干旱期间，这表明未来更频繁或更强烈的干旱可能会增加火灾的频率和强度。过去气候变化时期，松林和荒地植被的持续存在表明其具有相当大的生态抵抗力和恢复力。在未来超出这一历史变化范围的气候变化面前，未来的持续存在可能在一定程度上取决于将火重新引入这些系统。
