Dear all,
I want to estimate standardized effect size (SES) for three organism groups that have been quantified in different ways at each site.

According to the SI in Kraft et al. (2011) Disentangling the Drivers of β Diversity Along Latitudinal and Elevational Gradients. Science 333 (6050): 1755-1758
“The β deviations therefore represent a standard effect size, with positive values indicating more β-diversity than expected, and negative values indicating less β-diversity than expected under the null model.”

Zhou et al. (in press) Stochasticity, succession, and environmental perturbations in a fluidic ecosystem. PNAS.
also present estimates of the standard error of SES.

The help ?oecosimu (vegan library) describe the z-value of the oecosimu-statistic based on simulation as SES.

I now wonder, does the Kraft et al. (2011) definition of SES hold also for the SES calculated using oecosimu()? Thus, oecosimu() may report negative z?

The code that Kraft et al. provide randomly assign individuals to the plots.

I want to estimate SES for spiders, plants and fungi. At each site, the number of individuals of each species spider have been counted, the cover of each plant species have been recorded and the biomass of each fungal species have been measured.

Is oecosimu() appropriate for estimating SES for these three organism groups? If not, what do you suggest?

Literature suggestions where estimators of SES is discussed is most welcome.

Cheers,
Tord



	[[alternative HTML version deleted]]

