Department of Land, Air, and Water Resources, University of California Davis, Davis, CA 95616, USA.
Departments of Earth & Atmospheric Sciences and Biological Sciences, University of Alberta, Edmonton, AB, Canada T6G 2E3.
New Phytol. 2010 Jun;186(4):795-816. doi: 10.1111/j.1469-8137.2010.03284.x.
Conceptually, plant functional types represent a classification scheme between species and broad vegetation types. Historically, these were based on physiological, structural and/or phenological properties, whereas recently, they have reflected plant responses to resources or environmental conditions. Often, an underlying assumption, based on an economic analogy, is that the functional role of vegetation can be identified by linked sets of morphological and physiological traits constrained by resources, based on the hypothesis of functional convergence. Using these concepts, ecologists have defined a variety of functional traits that are often context dependent, and the diversity of proposed traits demonstrates the lack of agreement on universal categories. Historically, remotely sensed data have been interpreted in ways that parallel these observations, often focused on the categorization of vegetation into discrete types, often dependent on the sampling scale. At the same time, current thinking in both ecology and remote sensing has moved towards viewing vegetation as a continuum rather than as discrete classes. The capabilities of new remote sensing instruments have led us to propose a new concept of optically distinguishable functional types ('optical types') as a unique way to address the scale dependence of this problem. This would ensure more direct relationships between ecological information and remote sensing observations.
从概念上讲，植物功能类型代表了物种和广泛植被类型之间的分类方案。历史上，这些是基于生理、结构和/或物候特性，而最近，则反映了植物对资源或环境条件的反应。通常，基于经济类比的一个基本假设是，植被的功能作用可以通过受资源约束的形态和生理特征的关联集来识别，这是基于功能趋同的假设。利用这些概念，生态学家已经定义了多种功能特征，这些特征通常是上下文相关的，并且所提出的特征的多样性表明，对于普遍类别没有达成一致意见。从历史上看，遥感数据的解释方式与这些观察结果相似，通常侧重于将植被划分为离散类型，通常取决于采样尺度。与此同时，生态学和遥感领域的当前思维方式已经转向将植被视为连续体，而不是离散类。新的遥感仪器的功能使我们提出了一种新的光学可区分功能类型的概念（“光学类型”），这是解决这个问题的尺度依赖性的一种独特方法。这将确保生态信息和遥感观测之间有更直接的关系。
