The thin(ning) green line? Investigating changes in Kenya's seagrass coverage
The thin(ning) green line? Investigating changes in Kenya's seagrass coverage
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DOI：
10.1098/rsbl.2018.0227
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发表时间：
2018-11-01
期刊：
影响因子：
3.3
通讯作者：
Huxham, Mark
中科院分区：
文献类型：
--
作者：
Harcourt, William D.;Briers, Robert A.;Huxham, Mark
对海草分布的了解仅限于少数经过充分研究的地点，而在资源匮乏的地区（例如非洲）了解甚少，因此对海草碳储存的全球估计并不准确。在这里，我们分析了免费提供的 Sentinel-2 和 Landsat 图像，以量化 1986 年至 2016 年间肯尼亚海岸海草的当代覆盖范围和变化。通过实地调查和对历史海草的独立估计，我们估计肯尼亚海草的总覆盖面积为 317.1 +/- 27.2 km(2)，自 1986 年以来损失了 0.85% yr(-1)。损失从 2000 年的 0.29% yr(-1) 增加到 2016 年的 1.59% yr(-1)，释放了2.17 自 1986 年以来的 Tg 碳。轶事证据 表明捕捞压力是造成损失的一个重要原因，并且在不久的将来可能会加剧。如果这些结果对非洲具有代表性，则需要重新考虑对海草范围和损失的全球估计。
Knowledge of seagrass distribution is limited to a few well-studied sites and poor where resources are scant (e.g. Africa), hence global estimates of seagrass carbon storage are inaccurate. Here, we analysed freely available Sentinel-2 and Landsat imagery to quantify contemporary coverage and change in seagrass between 1986 and 2016 on Kenya's coast. Using field surveys and independent estimates of historical seagrass, we estimate total cover of Kenya's seagrass to be 317.1 +/- 27.2 km(2), following losses of 0.85% yr(-1) since 1986. Losses increased from 0.29% yr(-1) in 2000 to 1.59% yr(-1) in 2016, releasing up to 2.17 Tg carbon since 1986. Anecdotal evidence suggests fishing pressure is an important cause of loss and is likely to intensify in the near future. If these results are representative for Africa, global estimates of seagrass extent and loss need reconsidering.