Summary: - Species richness and soil properties in Pinus ponderosa forests - 231
Journal of Vegetation Science 18: 231-242, 2007
© IAVS; Opulus Press Uppsala.
Question: How are the effects of mineral soil properties on
of processes involving the forest overstory, soil organic matter,
soil nitrogen, and understory plant abundance?
Location: North-central Arizona, USA.
Methods:We sampled 75 0.05-ha plots across a broad soil gra-
dient in a Pinus ponderosa (ponderosa pine) forest ecosystem.
We evaluated multivariate models of plant species richness
using structural equation modeling.
Results: Richness was highest at intermediate levels of un-
derstory plant cover, suggesting that both colonization success
and competitive exclusion can limit richness in this system.
We did not detect a reciprocal positive effect of richness on
plant cover. Richness was strongly related to soil nitrogen in
the model, with evidence for both a direct negative effect and