23 research outputs found

    Overview of habitat history in subtropical oceanic island summit ecosystems

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    Summit ecosystems of oceanic islands constitute one of the most ephemeral and isolated ecosystems existing, harboring specific features that confer on their biota an outstanding distinctness. Summits are short-lived entities, being the last ecosystems to be constructed during the growth of the new oceanic island, and the first to vanish due either to island subsidence, island erosion, or both. Whereas their geological emergence/disappearance is controlled by the volcanic/erosion activity, Pleistocene glaciations in the past million years, by forcing the altitudinal shift of the timberline, have also likely created or destroyed summit ecosystems, enabling the appearance of alpine ecosystems during glacial maxima where they were not present in interglacial periods and vice versa. On the other hand, summit ecosystems constitute islands within islands, being more isolated from climatically similar ecosystems than the coastlines of the islands containing them. Thus summit biota, frequently displaying a high endemicity, may originate either through dispersal from other close summit ecosystems during peak periods, or from the colonization of the summits and later evolution to the new conditions from mid-altitude species of the same island. Conversely, if peak periods are absent, the disappearance of summit ecosystems implies the extinction or extirpation of their constitutive species. Current summit species have likely occupied a much larger area during glacial periods. Thus the summits may be classified as climatic refuges. This is especially the case if glacial periods were associated with much drier conditions on oceanic islands as is the case on continents

    Data Descriptor: Compilation of climate data from heterogeneous networks across the Hawaiian Islands

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    Long-term, accurate observations of atmospheric phenomena are essential for a myriad of applications, including historic and future climate assessments, resource management, and infrastructure planning. In Hawai\u27i, climate data are available from individual researchers, local, State, and Federal agencies, and from large electronic repositories such as the National Centers for Environmental Information (NCEI). Researchers attempting to make use of available data are faced with a series of challenges that include: (1) identifying potential data sources; (2) acquiring data; (3) establishing data quality assurance and quality control (QA/QC) protocols; and (4) implementing robust gap filling techniques. This paper addresses these challenges by providing: (1) a summary of the available climate data in Hawai\u27i including a detailed description of the various meteorological observation networks and data accessibility, and (2) a quality controlled meteorological dataset across the Hawaiian Islands for the 25-year period 1990-2014. The dataset draws on observations from 471 climate stations and includes rainfall, maximum and minimum surface air temperature, relative humidity, wind speed, downward shortwave and longwave radiation data
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