Data from: Incorporating interspecific competition into species-distribution mapping by upward scaling of small-scale model projections to the landscape

There are a number of overarching questions and debate in the scientific community concerning the importance of biotic interactions in species distribution models at large spatial scales. In this paper, we present a framework for revising the potential distribution of tree species native to the Western Ecoregion of Nova Scotia, Canada, by integrating the long-term effects of interspecific competition into an existing abiotic-factor-based definition of potential species distribution (PSD). The PSD model is developed by combining spatially explicit data of individualistic species’ response to normalized incident photosynthetically active radiation, soil water content, and growing degree days. A revised PSD model adds biomass output simulated over a 100-year timeframe with a robust forest gap model and scaled up to the landscape using a forestland classification technique. To demonstrate the method, we applied the calculation to the natural range of 16 target tree species as found in 1,240 provincial forest-inventory plots. The revised PSD model, with the long-term effects of interspecific competition accounted for, predicted that eastern hemlock (Tsuga canadensis), American beech (Fagus grandifolia), white birch (Betula papyrifera), red oak (Quercus rubra), sugar maple (Acer saccharum), and trembling aspen (Populus tremuloides) would experience a significant decline in their original distribution compared with balsam fir (Abies balsamea), black spruce (Picea mariana), red spruce (Picea rubens), red maple (Acer rubrum L.), and yellow birch (Betula alleghaniensis). True model accuracy improved from 64.2% with original PSD evaluations to 81.7% with revised PSD. Kappa statistics slightly increased from 0.26 (fair) to 0.41 (moderate) for original and revised PSDs, respectively.科学界针对大空间尺度下物种分布模型中生物交互作用的重要性存在诸多核心争议与未解问题。本研究提出了一套修订加拿大新斯科舍省西部生态区本土树种潜在分布的框架：将种间竞争的长期效应整合入现有基于非生物因子的潜在物种分布（Potential Species Distribution，简称PSD）定义中。该PSD模型通过整合物种对归一化入射光合有效辐射、土壤含水量以及生长度日数的个体响应空间显式数据构建而成。改进后的PSD模型则引入了通过可靠森林林窗模型模拟100年时间尺度下的生物量输出结果，并借助林地分类技术将其拓展至景观尺度。为验证该方法的有效性，研究基于加拿大新斯科舍省1240个省级森林清查样地中的16个目标树种自然分布范围开展了计算应用。在纳入种间竞争长期效应后，改进后的PSD模型预测：与香脂冷杉（Abies balsamea）、黑云杉（Picea mariana）、红云杉（Picea rubens）、红枫（Acer rubrum L.）以及黄桦（Betula alleghaniensis）相比，东部铁杉（Tsuga canadensis）、美国山毛榉（Fagus grandifolia）、白桦（Betula papyrifera）、红栎（Quercus rubra）、糖枫（Acer saccharum）以及美洲颤杨（Populus tremuloides）的原有分布范围将出现显著缩减。模型真实准确率从原始PSD评估的64.2%提升至改进后PSD的81.7%。原始与改进后PSD的Kappa统计值分别从0.26（一般）小幅提升至0.41（中等）。