Books that people in federal land management agencies should read.

Two of them:
Messy, by Tim Harford
Range, by David Epstein

The books in their entirety are excellent, and both have chapters that serve as excellent summaries of what’s wrong with federal land management agencies and why. In both cases, the authors are writing about similar organizations with similar problems—none of our problems are unique.

Annuals in the northern Chihuahuan Desert

An interesting question came up recently: What are the proportions of annual and perennial taxa in the plant diversity of the northern Chihuahuan Desert?

I have appropriate data from the BLM Las Cruces District—Doña Ana, Grant, Hidalgo, Luna, Otero, and Sierra counties, New Mexico—in the form of 4324 plant species richness plots. Most plots are circles with a 10m radius. The average number of taxa per plot is 18.5 and there are a total of 80,079 plant observations in the dataset. About 1280 taxa are represented, most at the species rank but with some varieties, subspecies, genera, sections, and subgenera. 30% of the taxa are annuals and 30.5% of the plant observations are annuals. Since the detection of annuals is much more dependent on season and recent precipitation than is detection of perennials, I think this is probably an underestimate relative to what the data would indicate if all plots had been visited under ideal conditions. How large that effect is I do not know, but if I had to guess, I think 35-40% of the observations would be annuals under ideal conditions.