The spatial scale at which demographic performance (e.g. net reproductive output) varies can profoundly influence landscape-level population growth and persistence, and many demographically pertinent processes such as species interactions and resource acquisition vary at fine-scales. We compared the magnitude of demographic variation associated with fine-scale heterogeneity (< 10 m), with variation due to larger-scale (> 1 ha) fluctuations associated with fire disturbance. We used a spatially explicit model within an IPM modeling frame-work to evaluate the demographic importance of fine-scale variation. We used a measure of expected lifetime fruit production, EF , that is assumed to be proportional to lifetime fitness. Demographic differences and their effects on EF , were assessed in a population of the herbaceous perennial Hypericum cumulicola (~ 2600 individuals), within a patch of Florida rosemary scrub (400 m x 80 m). We compared demographic variation over fine spatial scales to demographic variation between years across six years after a fire. Values of EF changed by orders of magnitude over < 10 m. This variation in fitness over fine spatial scales (< 10 m) is commensurate to post-fire changes in fitness for this fire-adapted perennial. A Life Table Response Experiment indicated that fine-scale spatial variation in vital rates, especially survival, explains as much change in EF as demographic changes caused by time-since-fire, a key driver in this system. Our findings show that environmental changes over a few tens of meters can have ecologically meaningful implications for population growth and extinction.

中文翻译：

---

适应度的精细空间变化可与适应火灾的物种的干扰引起的波动相媲美

人口表现（例如净繁殖产出）变化的空间尺度可以深刻影响景观水平的人口增长和持久性，许多人口相关的过程，如物种相互作用和资源获取，在精细尺度上变化。我们比较了与细尺度异质性（< 10 m）相关的人口统计学变化的幅度，以及与火灾干扰相关的更大规模（> 1 公顷）波动引起的变化。我们在 IPM 建模框架内使用空间显式模型来评估细尺度变化的人口统计学重要性。我们使用了预期终生水果产量 EF 的度量，该度量被假定为与终生适应度成正比。人口统计学差异及其对 EF 的影响，在佛罗里达迷迭香灌木丛 (400 mx 80 m) 内的多年生草本金丝桃种群（约 2600 只）中进行了评估。我们将精细空间尺度上的人口变化与火灾后六年间的人口变化进行了比较。EF 值在 < 10 m 范围内按数量级变化。这种在精细空间尺度 (< 10 m) 上的适应度变化与这种适应火的多年生植物的适应度在火后变化相称。生命表响应实验表明，生命率的精细空间变化，尤其是生存率，解释了 EF 的变化与火灾后时间引起的人口变化一样多，这是该系统的一个关键驱动因素。