Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada.
Coastal and Marine Research Centre, Australian Rivers Institute, School of Environment and Science, Griffith University, Gold Coast, Qld, Australia.
Glob Chang Biol. 2021 Sep;27(17):4096-4109. doi: 10.1111/gcb.15684. Epub 2021 Jun 20.
As human impacts increase in coastal regions, there is concern that critical habitats that provide the foundation of entire ecosystems are in decline. Seagrass meadows face growing threats such as poor water quality and coastal development. To determine the status of seagrass meadows over time, we reconstructed time series of meadow area from 175 studies that surveyed 547 sites around the world. We found an overall trajectory of decline in all seven bioregions with a global net loss of 5602 km (19.1% of surveyed meadow area) occurring since 1880. Declines have typically been non-linear, with rapid and historical losses observed in several bioregions. The greatest net losses of area occurred in four bioregions (Tropical Atlantic, Temperate North Atlantic East, Temperate Southern Oceans and Tropical Indo-Pacific), with declining trends being the slowest and most consistent in the latter two bioregions. In some bioregions, trends have recently stabilised or reversed. Losses, however, still outweigh gains. Despite consistent global declines, meadows show high variability in trajectories, within and across bioregions, highlighting the importance of local context. Studies identified 12 different drivers of meadow area change, with coastal development and water quality as the most commonly cited. Overall, however, attributions were primarily descriptive and only 10% of studies used inferential attributions. Although ours is the most comprehensive dataset to date, it still represents only one-tenth of known global seagrass extent, with conspicuous historical and geographic biases in sampling. It therefore remains unclear whether the bioregional patterns of change documented here reflect changes in the world's unmonitored seagrass meadows. The variability in seagrass meadow trajectories, and the attribution of change to numerous drivers, suggest we urgently need to improve understanding of the causes of seagrass meadow loss if we are to improve local-scale management.
随着人类活动在沿海地区的增加，人们担心为整个生态系统提供基础的关键生境正在减少。海草草甸面临着水质恶化和沿海开发等日益严重的威胁。为了确定海草草甸随时间的变化情况，我们从全球 547 个地点的 175 项研究中重建了草甸面积的时间序列。我们发现，在所有七个生物区中，海草草甸总体呈下降趋势，自 1880 年以来，全球已有 5602 公里（占调查草甸面积的 19.1%）的面积消失。下降趋势通常是非线性的，在几个生物区观察到快速和历史上的损失。面积损失最大的是四个生物区（热带大西洋、北大西洋东部温带、南大洋温带和热带印度洋-太平洋），后两个生物区的下降趋势最慢且最稳定。在一些生物区，趋势最近已经稳定或逆转。然而，损失仍然超过收益。尽管全球持续下降，但草甸在轨迹上表现出高度的变异性，在不同的生物区和生物区内都存在，这突显了局部背景的重要性。研究确定了 12 种不同的草甸面积变化驱动因素，其中沿海开发和水质是最常被引用的因素。然而，总体而言，归因主要是描述性的，只有 10%的研究使用了推断性归因。尽管我们的数据集是迄今为止最全面的，但它仍然只代表了已知全球海草草甸面积的十分之一，在采样方面存在明显的历史和地理偏见。因此，目前尚不清楚这里记录的生物区变化模式是否反映了世界上未监测到的海草草甸的变化。海草草甸轨迹的可变性，以及将变化归因于众多驱动因素，表明如果我们要改善对海草草甸损失的原因的理解，我们迫切需要改善对海草草甸损失的原因的理解，以改善对当地规模的管理。
