Windmuller-Campione Marcella A, Long James N
Department of Forest Resources, College of Food, Agriculture and Natural Resource Sciences, University of Minnesota, St. Paul, Minnesota, United States of America.
Department of Wildland Resources & Ecology Center, Utah State University, Logan, Utah, United States of America.
PLoS One. 2016 Aug 30;11(8):e0160324. doi: 10.1371/journal.pone.0160324. eCollection 2016.
As forest communities continue to experience interactions between climate change and shifting disturbance regimes, there is an increased need to link ecological understanding to applied management. Limber pine (Pinus flexilis James.), an understudied species of western North America, has been documented to dominate harsh environments and thought to be competitively excluded from mesic environments. An observational study was conducted using the Forest Inventory and Analysis Database (FIAD) to test the competitive exclusion hypothesis across a broad elevational and geographic area within the Intermountain West, USA. We anticipated that competitive exclusion would result in limber pine's absence from mid-elevation forest communities, creating a bi-modal distribution. Using the FIAD database, limber pine was observed to occur with 22 different overstory species, which represents a surprising number of the woody, overstory species commonly observed in the Intermountain West. There were no biologically significant relationships between measures of annual precipitation, annual temperature, or climatic indices (i.e. Ombrothermic Index) and limber pine dominance. Limber pine was observed to be a consistent component of forest communities across elevation classes. Of the plots that contained limber pine regeneration, nearly half did not have a live or dead limber pine in the overstory. However, limber pine regeneration was greater in plots with higher limber pine basal area and higher average annual precipitation. Our results suggest limber pine is an important habitat generalist, playing more than one functional role in forest communities. Generalists, like limber pine, may be increasingly important, as managers are challenged to build resistance and resilience to future conditions in western forests. Additional research is needed to understand how different silvicultural systems can be used to maintain multi-species forest communities.
随着森林群落持续经历气候变化与不断变化的干扰格局之间的相互作用，将生态学认识与应用管理联系起来的需求日益增加。白皮松（Pinus flexilis James.）是北美西部一种研究较少的物种，有记录表明它在恶劣环境中占主导地位，并且被认为在中生环境中会被竞争排除。利用森林资源清查与分析数据库（FIAD）进行了一项观测研究，以在美国西部山间地区广泛的海拔和地理区域内检验竞争排除假说。我们预计竞争排除会导致中海拔森林群落中没有白皮松，从而形成双峰分布。通过FIAD数据库观察到，白皮松与22种不同的上层树种共存，这在西部山间地区常见的木本上层树种中是一个惊人的数量。年降水量、年温度或气候指数（即干湿指数）的测量值与白皮松优势度之间没有生物学上的显著关系。观察到白皮松是各海拔森林群落中始终存在的组成部分。在包含白皮松更新的样地中，近一半的样地在上层没有活的或死的白皮松。然而，在白皮松基部面积较大且年平均降水量较高的样地中，白皮松更新情况更好。我们的结果表明，白皮松是一种重要的广适性物种，在森林群落中发挥着多种功能作用。像白皮松这样的广适性物种可能会变得越来越重要，因为管理者面临着增强西部森林对未来状况的抵抗力和恢复力的挑战。需要进一步研究以了解如何利用不同的造林系统来维持多物种森林群落。
