Using Paleolandscape Modeling to Investigate the Impact of Native American-Set Fires on Pre-Columbian Forests in the Southern Sierra Nevada, California, USA
Using Paleolandscape Modeling to Investigate the Impact of Native American-Set Fires on Pre-Columbian Forests in the Southern Sierra Nevada, California, USA
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DOI：
10.1080/24694452.2018.1470922
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发表时间：
2018-11-02
影响因子：
3.9
通讯作者：
Scheller, Robert M.
中科院分区：
文献类型：
--
作者：
Klimaszewski-Patterson, Anna;Weisberg, Peter J.;Scheller, Robert M.
根据人种学的记载，加利福尼亚州的美洲原住民广泛使用低强度的地面火来管理陆地资源，然而这种做法对森林组成和结构的影响在很大程度上仍不清楚。尽管许多古环境研究都在讨论替代性解释是否表明气候或人为的景观变化驱动因素，但现有的数据来源(例如花粉、木炭)通常不足以解决人为影响，也不允许进行假设检验。我们使用LANDIS-II的建模方法，这是一个空间上显式的森林演替和干扰模型，以测试是否有必要增加美洲原住民背景的地表火灾，以接近从化石花粉重建的植被变化。我们使用加利福尼亚州红杉国家森林霍利草地现有的1600年的花粉和木炭记录作为经验数据集，并将其与气候和人为火灾制度的模拟结果进行比较。我们发现，人为燃烧的增加最接近于化石花粉重建的植被变化，特别是在较长时间的凉爽、潮湿时期，同时区域美洲原住民活动较强(1550-1050和750-100卡尔·年BP)。闪电引起的野火要在统计上接近花粉记录，在小冰河时代(750-100卡尔·年)每年需要比现代时期(公元1985-2006年)观察到的至少20倍的点燃次数和870%的燃烧面积，我们认为这种自然火灾增加的水平非常不可能。这些结果表明：(1)人为燃烧可能是该地区前哥伦布时期森林结构的重要原因；(2)动态景观模型为验证古环境变化假说提供了一种有价值的方法。
Ethnographic accounts document widespread use of low-intensity surface fires by California's Native Americans to manage terrestrial resources, yet the effects of such practices on forest composition and structure remain largely unknown. Although numerous paleoenvironmental studies debate whether proxy interpretations indicate climatic or anthropogenic drivers of landscape change, available data sources (e.g., pollen, charcoal) are generally insufficient to resolve anthropogenic impacts and do not allow for hypothesis testing. We use a modeling approach with LANDIS-II, a spatially explicit forest succession and disturbance model, to test whether the addition of Native American-set surface fires was necessary to approximate vegetation change as reconstructed from fossil pollen. We use an existing 1,600-year pollen and charcoal record from Holey Meadow, Sequoia National Forest, California, as the empirical data set to which we compared modeled results of climatic and anthropogenic fire regimes. We found that the addition of anthropogenic burning best approximated fossil pollen-reconstructed vegetation change, particularly during periods of prolonged cooler, wetter periods coinciding with greater regional Native American activity (1550-1050 and 750-100 cal yr BP). For lightning-caused wildfires to statistically approximate the pollen record required at least twenty times more ignitions and 870 percent more area burned annually during the Little Ice Age (750-100 cal yr BP) than observed during the modern period (AD 1985-2006), a level of natural fire increase we consider highly improbable. These results demonstrate that (1) anthropogenic burning was likely an important cause of pre-Columbian forest structure at the site and (2) dynamic landscape models provide a valuable method for testing hypotheses of paleoenvironmental change.