A model for regional-scale oak savanna management: the roles of fire, canopy, and soils for understory plant diversity

We used these data to analyze direct effects of prescribed fire and
mechanical thinning on oak savanna groundlayer plant diversity, indirect
effects via changes to ecosystem structure (canopy openness and litter
depth), and how these effects depended on soil productivity context and
the spatial scale at with diversity was analyzed (mean 1-m2 plant species
richness vs. total plot 1000-m2 plant species richness). The dataset is
comprised of those two scales of richness, which are the primary response
variables. We analyzed the effects of three primary management variables:
fire frequency (number of fires since 2000), canopy thinning (the
proportion of woody stems > 5 cm DBH removed), and shrub/sapling
thinning (the proportion of woody stems < 5 cm DBH removed).
Indirect effects via management effects on ecosystem structure (% canopy
openness and mean litter depth) were modeled using structural equation
modeling, and context-dependence was analyzed using interaction terms
between soil productivity (in the form of a PCA axis) and each management
variable in mixed models.