Plant Diversity in Relation to Plant Production and Disturbance by Voles in Alaskan Tundra Communities

Abstract

Vascular plant species richness and diversity were compared to aboveground vascular plant production, vole disturbance, and soil depth across snowbank and solifluction terrace gradients in an interior Alaskan tundra. Plant diversity, productivity, and disturbance by voles all vary curvilinearly across these gradients. Species richness and diversity were not correlated with productivity in a simple linear fashion. Richness and diversity were correlated strongly with intensity of vole disturbance. Diversity was also significantly related in a curvilinear fashion to productivity: diversity first rises and then falls as productivity increases. Such a curvilinear relationship has been predicted theoretically by others. Because productivity is related to soil fertility in these sites, the curvilinear diversity-productivity relationship suggests that Tilman''s (1982) model for plant diversity may apply to these communities.