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）旨在助力管理者引导人类活动转向可持续开发模式，并最大限度降低海洋开发利用中的使用者权益冲突。关键的首要步骤是量化海洋生物群落的空间格局，以此深入理解生态系统的结构、功能与服务。然而，近岸生境兼具大空间尺度、高经济价值与人类活动高密度的特征，往往使得量化该类海洋生态系统组分的工作格外艰巨。为应对这一挑战，我们开发了一套评估方法，该方法通过利用非生物替代指标（abiotic proxies），能够快速表征近岸底栖环境中分辨率相对较高的海洋生物群落。我们在缅因州大陆架300公里的沿岸浅水区（水深<100米）对该评估方法进行了验证——该区域通常布有大量带浮标的龙虾笼，这使得拖网采样设备（即底拖网，otter trawls）难以开展全面调查。2010-2013年夏季，我们采用小型遥控无人潜水器（remotely operated vehicle, ROV）开展了分层随机调查，借此得以避开龙虾浮标，并对所有底栖大型动物进行了物种级别的定量统计。通过按底质类型、水深以及近岸水团进行分层采样，我们发现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%至59%的显著变异。总体而言，生物群落的密度、多样性与生物量随底质复杂度的提升而显著升高（即从沙泥底质过渡到岩礁底质）。生物群落的多样性、生物量与经济价值也随水深的增加而显著下降。此外，底层鱼类密度、固着无脊椎动物密度、物种多样性以及生物群落生物量自东向西呈递增趋势，而移动无脊椎动物的丰度与经济价值则呈递减趋势，这一结果主要与缅因州沿岸流系统（Maine Coastal Current system）迥异的水团特征（即夏季流向、流速与温度）相对应。我们将模拟预测结果与现有非生物条件的地理信息系统（Geographic Information System, GIS）图层相结合，得以将重要的群落属性进行空间尺度外推，借此界定海洋空间规划的关键基础生态原则，并识别出那些底部扰动活动对底栖生物群落影响最小的优先区域。最终我们得出结论：非生物替代指标可作为海洋群落组装的强驱动因子，因此对于人类活动密集的近岸生境而言，非生物替代指标是开展海洋生物群落空间外推的实用工具。