Secondary Succession and the Pattern of Plant Dominance Along Experimental Nitrogen Gradients

作者：David Tilman · 发表于：Ecological Monographs · 年份：1987 · DOI：10.2307/2937080 · 被引用次数：1084 · 研究领域：Ecology and Vegetation Dynamics Studies、Botany, Ecology, and Taxonomy Studies、Botany and Plant Ecology Studies

In 1982, experimental nitrogen gradients were established on both existing and disturbed (disked) vegetation in three fields (abandoned 14, 25, and 48 yr) and on existing vegetation in native oak savannah. Each of these seven gradients contained five or six replicates of each of nine treatments that differed in the annual rate of nitrogen addition. In none of the fields did plant biomass, height, species richness, or light penetration respond to addition of P, K, Ca, Mg, S, and trace metals. In contrast, plant biomass and height increased significantly, and light penetration and species richness decreased significantly, with added nitrogen along all seven gradients. On average, >60% of the species had been displaced from high—nitrogen treatments by 1985. Nitrogen addition led to a period of transient dominance by certain species. Species that reached peak relative abundance in high—nitrogen treatments in 1982 tended to be rare in all but the low—nitrogen treatments by 1985. In contrast, the relative abundances of most species that dominated the high—nitrogen treatments in 1985 did not increase along the nitrogen gradients in 1982. The relative or absolute abundances of most common species changed significantly along the experimental gradients in at least 1 yr. By 1985, many common species were differentiated in their distributions along the seven gradients. In general, early successional annuals and short—lived perennials and plants of short stature at maturity reached their ...