Decreased temperature variance associated with biotic composition enhances coastal shrub encroachment
Decreased temperature variance associated with biotic composition enhances coastal shrub encroachment
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DOI：
10.1038/s41598-020-65161-3
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发表时间：
2020-05
影响因子：
4.6
通讯作者：
L. Wood;S. Hays;J. Zinnert
中科院分区：
文献类型：
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作者：
L. Wood;S. Hays;J. Zinnert
在土地利用变化和气候变化的推动下，世界范围内发生了从草原为主的景观向灌木为主的景观的转变，影响了景观功能、生物多样性和生产力。冬季气温变暖是本土常绿灌木莫雷拉·西里弗拉在沿海景观中扩张的主要驱动力。灌木在这些生境中的建立改变了小气候，但对季节差异和小气候变化知之甚少。我们研究了灌木对沿海草地三个植被带：草本带、过渡带和灌木带小气候变化、群落组成和群落生理功能的影响。利用时间序列分析的新应用，我们解释了弗吉尼亚海岸保护区长期生态研究地点灌木入侵的小气候变化变化和机制。随着灌丛的形成，多样性降低，草类/杂草盖度较小，蒸腾作用和年生产力增加。灌丛显著降低了气温变化，对最大气温、最低气温和最高地温有正向影响。我们还表明，小气候温度缓和降低了过渡地区夏季的极端温度，甚至在融合成完整的灌木丛之前也是如此。莫雷拉对弗吉尼亚州屏障岛屿的侵蚀是由于当地暴露在寒冷温度下的减少，以及非生物小气候变化和生物生理功能的加强。植物群落组成从草地向灌木灌丛的转变改变了障碍岛在生产力中的作用，并可能对岛屿的自然弹性产生影响。
Regime shift from grasslands to shrub-dominated landscapes occur worldwide driven by altered land-use and climate change, affecting landscape function, biodiversity, and productivity. Warming winter temperatures are a main driver of expansion of the native, evergreen shrub,Morella cerifera, in coastal landscapes. Shrub establishment in these habitats alters microclimate, but little is known about seasonal differences and microclimate variance. We assessed influence of shrubs on microclimate variance, community composition, and community physiological functioning across three vegetation zones: grass, transitional, and shrub in a coastal grassland. Using a novel application of a time-series analysis, we interpret microclimatic variance modification and elucidate mechanisms of shrub encroachment at the Virginia Coast Reserve, Long-Term Ecological Research site. As shrub thickets form, diversity is reduced with little grass/forb cover, while transpiration and annual productivity increase. Shrub thickets significantly reduced temperature variance with a positive influence of one day on the next in maximum air, minimum air, and maximum ground temperature. We also show that microclimatic temperature moderation reduces summer extreme temperatures in transition areas, even before coalescence into full thickets. Encroachment ofMorella ceriferaon the Virginia barrier islands is driven by reduced local exposure to cold temperatures and enhanced by abiotic microclimatic modification and biotic physiological functioning. This shift in plant community composition from grassland to shrub thicket alters the role of barrier islands in productivity and can have impacts on the natural resilience of the islands.