Geography and Environmental Studies, University of Hawai'i-Hilo, Hawaii 96720, USA.
Ecology. 2011 Feb;92(2):518-25. doi: 10.1890/10-0341.1.
In January 1958, a survey of alpine flora was conducted along a recently constructed access road across the upper volcanic slopes of Mauna Loa, Hawaii (2525-3397 m). Only five native Hawaiian species were encountered on sparsely vegetated historic and prehistoric lava flows adjacent to the roadway. A resurvey of roadside flora in 2008 yielded a more than fourfold increase to 22 species, including nine native species not previously recorded. Eight new alien species have now invaded this alpine environment, although exclusively limited to a few individuals in ruderal habitat along the roadway. Alternative explanations for species invasion and altitudinal change over the past 50 years are evaluated: (1) changes related to continuing primary succession on ameliorating (weathering) young lava substrates; (2) local climate change; and (3) road improvements and increased vehicular access which promote enhanced car-borne dispersal of alien species derived from the expanding pool of potential colonizers naturalized on the island in recent decades. Unlike alpine environments in temperate latitudes, the energy component (warming) in climate change on Mauna Loa does not appear to be the unequivocal driver of plant invasion and range extension. Warming may be offset by other climate change factors including rainfall and evapotranspiration.
1958 年 1 月，对夏威夷莫纳罗亚火山（2525-3397 米）上部火山坡上最近修建的一条通道沿线的高山植物进行了调查。在与道路相邻的植被稀疏的历史和史前熔岩流上，只遇到了五种本地夏威夷物种。2008 年对路边植物的重新调查使物种数量增加了四倍多，达到 22 种，其中包括以前没有记录的 9 种本地物种。现在已经有 8 种外来物种入侵了这个高山环境，尽管它们仅限于道路沿线贫瘠生境中的少数个体。对过去 50 年物种入侵和海拔变化的替代解释进行了评估：（1）与改善（风化）年轻熔岩基质上持续的原始演替有关的变化；（2）局部气候变化；（3）道路改善和车辆通行增加，促进了从岛上近几十年来归化的潜在殖民者群体中衍生的外来物种的汽车传播。与温带地区的高山环境不同，莫纳罗亚火山气候变化中的能量组成（变暖）似乎不是植物入侵和范围扩展的明确驱动因素。变暖可能会被包括降雨量和蒸散量在内的其他气候变化因素所抵消。
