Data for: Bed-scale impact and recovery of a commercially important intertidal seaweed

As the value of ecosystem-based management (EBM) approaches is increasingly recognized in marine ecosystems, it is critical that the impacts of resource harvest are assessed at various spatial scales. This is particularly true for habitat-forming resources, such as wild seaweeds, that act as foundation species by physically structuring ecosystems. The impacts of spatially heterogeneous harvest may change with scale and have different management implications based on the ecosystem process or organism under consideration. Ascophyllum nodosum (hereafter rockweed) is a canopy-forming fucoid seaweed endemic to rocky coastlines in the North Atlantic Ocean that has been harvested for centuries. We conducted a Before-After Control-Impact study of commercial rockweed harvest at 38 sites across the coast of Maine (USA) from 2018 to 2020 in an effort to understand impact and one-year recovery of two rockweed bed structural characteristics, height and biomass, at a scale similar to a single harvest event. Our results indicate that rockweed harvest is spatially heterogeneous at the scale of the rockweed bed, and as a result, the effect sizes of harvest at this scale are smaller than those reported in previous studies that assessed smaller spatial scales. Mean rockweed biomass recovered to pre-harvest values after one year of recovery, but mean rockweed height remained lower at impacted sites. While post-harvest recovery was generally high in our study, sites that experienced higher intensities of harvest were less likely to fully recover height or biomass one year post-harvest. Our findings provide resource managers with a bed-scale perspective that can inform EBM approaches, particularly for population-level management of harvested resources and impacts of harvest on highly mobile organisms—such as birds and fish—that interact with these ecosystems at larger spatial scales.

随着基于生态系统的管理（Ecosystem-based Management, EBM）理念在海洋生态系统中的价值日益得到认可，对资源捕捞的影响开展多空间尺度评估已成为至关重要的工作。这一点对于构建生境的资源而言尤为关键，例如野生海藻——这类生物通过物理结构作用构建生态系统，属于关键建群种。空间异质性捕捞的影响可能随尺度发生变化，且根据所关注的生态系统过程或生物类群，其管理意义也有所不同。泡叶藻（Ascophyllum nodosum，下文简称岩藻（rockweed））是一种冠层形成型褐藻，仅分布于北大西洋的岩质海岸线，其捕捞历史已长达数百年。我们于2018年至2020年间，在美国缅因州沿岸的38个样地开展了基于前后-对照-影响（Before-After Control-Impact）的商业岩藻捕捞研究，旨在探究单次捕捞尺度下，两处岩藻床结构特征——高度与生物量——所受的影响以及为期一年的恢复情况。研究结果表明，在岩藻床尺度下，岩藻捕捞具有空间异质性，因此该尺度下捕捞的效应量小于此前针对更小空间尺度开展的相关研究报道结果。经过一年的恢复后，岩藻的平均生物量恢复至捕捞前水平，但受影响样地的平均高度仍未恢复至原有水平。尽管本研究中捕捞后的整体恢复情况良好，但捕捞强度更高的样地，其岩藻高度与生物量在捕捞后一年完全恢复的概率更低。本研究结果为资源管理者提供了床尺度的视角，可为基于生态系统的管理（EBM）方法提供参考，尤其适用于被捕捞资源的种群级管理，以及捕捞对在更大空间尺度上与该生态系统互动的高移动性生物（如鸟类与鱼类）所产生的影响评估。