Resource use efficiency as a function of species richness and stand composition in upper montane conifer forests of the Sierra Nevada

Abstract

Abstract Questions: 1. Does resource use efficiency increase with increased species richness in conifer forests? 2. Do patterns found in resource use support niche differentiation/complementarity between species, or is any increase indicative of a selection effect? Location: All data were collected from upper montane (2200–2600 m a.s.l) conifer forests of the Desolation Wilderness in the central California Sierra Nevada, USA. Methods: We established 281 plots of varying levels of conifer richness throughout the wilderness area. Within each plot we used hemispherical photos to measure canopy closure and LAI, total soil carbon and nitrogen from the A-horizon, and stand basal area. We used linear regression and ANOVA to analyse the relationship between stand species richness and resource availability. Results: We found no correlation of either soil nitrogen or carbon with stand biomass. Nor did soil nitrogen and carbon levels change with species richness. Canopy closure increased with species richness but al...