Biodiversity assessment at broad scale
大尺度生物多样性评价

How to make a balance between reducing sampling efforts and gaining accurate information is a central problem in broad scale biodiversity assessment. This article tries to address this question by introducing multiscale methodology. We first provide a definition of broad scale assessment, then highlight this problem after reviewing the history of global assessments. In the third part, we summarize the methodology of assessment design from five aspects: sampling strategy, surrogate species, rapid assessment technique, indicators and remote sensing techniques. Finally, a hierarchical multiscale method is described that provides a better balance. In a typical multiscale assessment, biodiversity is characterized at a series of spatial scales, thus it is different from the traditional sampling design. Correspondingly, multiscale planning can be simply divided into two categories: one comprises sampling designs with loosely defined scales, and the other comprises those with strictly defined scales. The former has the advantage of synthesizing information more easily among multiple scales. In our view, the essence of this method is construction of a middle scale, which can be realized by "top down" and "bottom up" approaches. The ideal method for biodiversity conservation based on this multiscale methodology is to plan in the broad scale context, to integrate at the middle scale and to act at the local, manageable scale.