Gosz James R
Ecol Appl. 1992 Aug;2(3):248-261. doi: 10.2307/1941859.
Gradient analysis is a powerful technique to analyze for, and detect change in, the dynamics, structure, and function of ecosystems. Boundaries between zones or communities occur at distinctive locations along environmental gradients and are expected to be especially sensitive to environmental change. Gradient analysis can be performed at a range of scales, and allows integration and extrapolation of change across scales from those associated with communities to those of biomes. This review outlines the properties of gradients in space and time and uses an example of forests in the Rocky Mountain Physiographic Province to demonstrate constraints, the complex mosaics associated with distributional limits, transfers across boundaries, the role of disturbance, and threshold dynamics. A climate-change scenario is developed to hypothesize future changes in boundary movements, community mosaics, and ecosystem properties along elevational and latitudinal gradients in the Rocky Mountain Province. Mechanistic explanations of ecological phenomena that are necessary for management require information on: (1) the physical environmental constraints operating on the ecosystem; (2) the biota that operate within those constraints; and (3) the interactions among the biota and between the biota and environment. The relative importance of these three elements differs between environments and along environmental gradients. Biota and their interactions may account for much of the variance in system structure and function in mesic environments, while abiotic factors may limit biotic activity in less-favorable (arid) habitats. Plot studies that are analyzed as points along broader scale environmental gradients can provide quantitative information on the major driving variables, and broad-scale analyses of environmental factors along the gradient generate the information for extrapolating between sites and across scales. Modeling that includes such spatial gradients provides the foundation for local to regional management programs.
梯度分析是一种用于分析和检测生态系统动态、结构及功能变化的强大技术。区域或群落之间的边界出现在沿环境梯度的特定位置，预计对环境变化特别敏感。梯度分析可在一系列尺度上进行，并允许将跨尺度的变化进行整合和外推，这些变化范围从与群落相关的尺度到生物群落的尺度。本综述概述了时空梯度的特性，并以落基山自然地理省内的森林为例，展示了限制因素、与分布界限相关的复杂镶嵌体、跨边界的转移、干扰的作用以及阈值动态。构建了一个气候变化情景，以推测落基山省内沿海拔和纬度梯度的边界移动、群落镶嵌体及生态系统特性的未来变化。管理所需的生态现象的机理解释需要以下方面的信息：（1）作用于生态系统的物理环境限制因素；（2）在这些限制因素内起作用的生物区系；（3）生物区系之间以及生物区系与环境之间的相互作用。这三个要素的相对重要性在不同环境和沿环境梯度的情况下有所不同。在中生环境中，生物区系及其相互作用可能解释了系统结构和功能的大部分变异，而非生物因素可能在较不利（干旱）的栖息地限制生物活动。作为更广泛尺度环境梯度上的点进行分析的样地研究可以提供有关主要驱动变量的定量信息，而沿梯度对环境因素进行的广泛尺度分析则生成了用于在不同地点和尺度之间进行外推的信息。包含此类空间梯度的建模为地方到区域的管理计划提供了基础。
