FUNCTIONAL AND STRUCTURAL CONVERGENCE OF TEMPERATE GRASSLAND AND SHRUBLAND ECOSYSTEMS

Abstract

We analyzed the similarity of structural and functional characteristics of temperate grassland and shrubland ecosystems of North and South America. We based our analyses on correlative models that describe the climatic controls of grassland and shrubland structure and functioning at regional scales. We evaluated models that describe the regional distribution of plant functional types (C 3 and C4 grasses and shrubs), soil organic carbon (SOC), and aboveground net primary production (ANPP) and its seasonality. To evaluate the predictive power of the models, we compared their estimates against observed data. We derived data sets, independent from those used to generate the models in North America, from climatically similar areas in South America. Our results support the notion that, in climatically similar regions, structural and func- tional attributes such as plant functional type composition, SOC, ANPP, and ANPP sea- sonality have similar environmental controls, independent of the evolutionary history of the regions. The study suggests the existence of an important degree of convergence at regional scales in both functional and structural attributes. It also points out differences in the regional patterns of some attributes that require further analyses.