Abstract The configuration of a habitat often reflects its conservation status and, to be effective, the conservation actions to be implemented must be adapted to local environmental conditions and human activities. Here, we take advantage of a fine resolution map (1:10000) of marine habitats to study the spatial configuration of Posidonia oceanica seagrass beds, a marine habitat of great ecological and economic importance. Six different composition and landscape descriptors were calculated at different scales (grid cells of 400 m × 400 m, 200 m × 200 m and 100 m × 100 m) between 0 and 40 m deep along 1700 km of French Mediterranean coastline (mainland and Corsica). A Random Forest approach was applied to relate these landscape descriptors to anthropogenic and environmental factors and to assess their relative importance. The best predictive power of the Random Forest models was obtained for 100 m × 100 m grid cells with models explaining 87% of the variance of the decline index and 70% of the variance of the cohesion index. The identification of threshold points for all environmental variables allowed to localize seagrass beds in either good or bad environmental conditions. We also identified sites whose spatial configuration was degraded despite good environmental conditions. These were sites with greater influence from human activities that could benefit from proactive conservation measures.

中文翻译：

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确定 Posidonia Oceanica 海草床的重点保护区

摘要 栖息地的配置往往反映了其保护状况，要实施的保护行动必须适应当地的环境条件和人类活动，才能有效。在这里，我们利用海洋栖息地的高分辨率地图 (1:10000) 来研究 Posidonia Oceanica 海草床的空间配置，这是一个具有重要生态和经济重要性的海洋栖息地。沿着 1700 公里法国地中海海岸线（大陆和科西嘉岛）深度在 0 到 40 m 之间的不同尺度（400 m × 400 m、200 m × 200 m 和 100 m × 100 m 的网格单元）计算了六种不同的组成和景观描述符）。应用随机森林方法将这些景观描述符与人为和环境因素联系起来，并评估它们的相对重要性。随机森林模型的最佳预测能力是针对 100 m × 100 m 网格单元获得的，模型解释了下降指数的 87% 的方差和内聚指数的 70% 的方差。识别所有环境变量的阈值点，可以在良好或恶劣的环境条件下定位海草床。我们还确定了尽管环境条件良好但空间配置仍会退化的地点。这些是受人类活动影响较大的地点，可以从积极的保护措施中受益。识别所有环境变量的阈值点，可以在良好或恶劣的环境条件下定位海草床。我们还确定了尽管环境条件良好但空间配置仍会退化的地点。这些是受人类活动影响较大的地点，可以从积极的保护措施中受益。识别所有环境变量的阈值点，可以在良好或恶劣的环境条件下定位海草床。我们还确定了尽管环境条件良好但空间配置仍会退化的地点。这些是受人类活动影响较大的地点，可以从积极的保护措施中受益。