Data from: Abiotic proxies for predictive mapping of near-shore benthic assemblages: Implications for marine spatial planning

Marine spatial planning (MSP) should assist managers in guiding human activities towards sustainable practices and in minimizing user-conflicts in our oceans. A necessary first step is to quantify spatial patterns of marine assemblages in order to understand the ecosystem's structure, function, and services. However, the large spatial scale, high economic value, and density of human activities in near-shore habitats often makes quantifying this component of marine ecosystems especially daunting. To address this challenge, we developed an assessment method that employs abiotic proxies to rapidly characterize marine assemblages in near-shore benthic environments with relatively high resolution. We evaluated this assessment method along 300 km of the State of Maine's coastal shelf (< 100m depth)—a zone where high densities of buoyed lobster traps typically preclude extensive surveys by towed sampling gear (i.e., otter trawls). During the summer months of 2010-2013, we implemented a stratified-random survey using a small remotely operated vehicle that allowed us to work around lobster buoys and to quantify all benthic megafauna to species. Stratifying by substrate, depth, and coastal water masses, we found that abiotic variables explained a significant portion of variance (37- 59%) in benthic species composition, diversity, biomass and economic value. Generally, the density, diversity, and biomass of assemblages significantly increased with the substrate complexity (i.e., from sand-mud to ledge). The diversity, biomass, and economic value of assemblages also decreased significantly with increasing depth. Lastly demersal fish densities, sessile invertebrate densities, species diversity, and assemblage biomass increased from east to west, while the abundance of mobile invertebrates and economic value decreased, corresponding mainly to the contrasting water-mass characteristics of the Maine Coastal Current system (i.e., summertime current direction, speed, and temperature). Integrating modeled predictions with existing GIS layers for abiotic conditions allowed us to scale up important assemblage attributes to define key foundational ecological principles of MSP and to find priority regions where some bottom-disturbing activities would have minimal impact to benthic assemblages. We conclude that abiotic proxies can be strong forcing functions for the assembly of marine communities and therefore useful tools for spatial extrapolations of marine assemblages in congested (heavily used) near-shore habitats.

海洋空间规划（Marine Spatial Planning, MSP）旨在协助管理者引导人类活动转向可持续实践，并最大限度降低海洋中的用户冲突。要实现这一目标，首要的必要步骤是量化海洋生物群落的空间分布格局，以此理解生态系统的结构、功能与服务。然而，近岸生境具有空间尺度广阔、经济价值高、人类活动密集的特点，这使得量化该海洋生态系统组分的工作尤为艰巨。

为应对这一挑战，我们开发了一种评估方法，通过非生物替代指标（abiotic proxies）快速表征近岸底栖环境中相对高分辨率的海洋生物群落。我们在美国缅因州沿海陆架（水深<100米）的300公里沿岸区域对该评估方法进行了验证——该区域内浮置龙虾笼密度极高，通常会妨碍拖网采样设备（otter trawls，底拖网）开展大规模调查。2010-2013年夏季，我们采用小型遥控无人潜水器开展了分层随机调查，该设备可绕行龙虾浮标，并能将所有底栖大型生物鉴定至物种级别并完成定量统计。

我们依据底质、水深与沿海水团进行分层，结果显示非生物变量能够解释底栖物种组成、多样性、生物量及经济价值中37%~59%的显著变异量。总体而言，生物群落的密度、多样性与生物量随底质复杂度提升（即从沙泥底质向岩礁底质过渡）显著增加；群落的多样性、生物量与经济价值也随水深增加而显著下降。最后，底层鱼类密度、固着无脊椎动物密度、物种多样性及群落生物量自东向西逐渐升高，而移动无脊椎动物丰度与经济价值则呈下降趋势，这主要与缅因沿岸流系统（即夏季的流向、流速与水温）的水团特征差异相对应。

通过将模型预测结果与现有的非生物条件地理信息系统（Geographic Information System, GIS）图层相结合，我们能够将关键群落属性进行尺度拓展，从而明确海洋空间规划的核心基础生态原则，并识别出海底扰动活动对底栖生物群落影响极小的优先区域。我们的研究结论表明，非生物替代指标可作为海洋群落构建的关键驱动因子，因此在人类活动密集的近岸生境中，其可作为海洋生物群落空间外推的有效工具。