Contrasting patterns of resource limitation in tree seedlings across a gradient in soil texture

• Published in: Canadian journal of forest research Vol. 25; no. 10; pp. 1583 - 1594
• Main Authors: Knox, R.G, Harcombe, P.A, Elsik, I.S
• Format: Journal Article
• Language: English
• Published: 01.10.1995
• Subjects: Acer rubrum; dry matter accumulation; forest soils; gradients; light; limiting factors; Liquidambar styraciflua; nitrogen; nutrient availability; phosphorus; Pinus taeda; plant ecology; resource competition; seedling growth; seedlings; soil texture; water availability; Texas
• ISSN: 0045-5067; 1208-6037
• DOI: 10.1139/x95-173

Resource competition theory for terrestrial plant communities explains gradients in species composition among various habitats as the outcome of differential supply and demand for limiting resources. To examine one group of assumptions of this theory, for forest vegetation in southeastern Texas, we grew seedlings of three broadly distributed tree species, Acer rubrum L. (red maple), Liquidambar styraciflua L. (sweetgum), and Pinus taeda L. (loblolly pine), in intact soil cores collected from three sites located along a gradient in soil texture. We tested resource limitation in a temperature-controlled greenhouse with nutrient fertilization, light, and moisture treatments applied in a resource-minus or screening design. This design provided most resources at levels not limiting for growth while simulating (potentially limiting) field conditions for a single resource or group of related resources. Light was most limiting with clay-rich floodplain soil cores under simulated floodplain forest conditions. Soil nutrients were most limiting in sandy upland soil cores under upper slope forest conditions. Both light and soil nutrients were strongly limiting with loamy intermediate soil cores under simulated mesic forest conditions. The most limiting soil resource was phosphorus. The pattern of reciprocal limitation by aboveground or belowground resources in extreme habitats and joint limitation in intermediate habitats was consistent with requirements of the theory.