In this Colorado study, authors applied a gap dynamics conceptualization of succession to a semiarid grassland, by focusing on gaps produced in the belowground resource space by death of an individual of the dominant species, the perennial grass, blue grama (Bouteloua gracilis). Average time required for B. gracilis to dominate biomass on a simulated plot was 20 years, a more rapid recovery time than has been reported from other studies of large-scale disturbances. A second set of simulations incorporating effects of seed availability resulted in an average recovery time of 65 years. Aboveground biomass on the simulated plots was dominated by B. gracilis through time and space. Relative proportion of aboveground biomass and average biomass for each species was comparable to the composition of shortgrass plant communities at the Central Plains Experimental Range. Therefore, this initial analysis supports the idea that a gap dynamics conceptualization of shortgrass plant communities, based on the importance of small, frequently-occurring disturbances and belowground resources, provides a promising alternative to a conceptual model that emphasized effects of large-scale disturbances. Initial indications suggest that gap processes are important to this community.
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