DOI: 10.5061/dryad.brv15dvdc
title: Data from: Does evenness even exist?

description: The idea that diversity is a combination of species richness and the
 so-called "evenness" of count distributions is a bedrock concept
 in ecology. Researchers often compute stand-alone evenness indices. They
 also examine Hill numbers related to Shannon's H and Simpson's D
 because these metrics balance richness and "evenness" to various
 degrees. But evenness is an operationally problematic abstraction, not a
 thing out in the world. Evenness indices and Hill numbers in empirical
 data are overly sensitive to the abundance of dominant species, poorly
 replicable within communities, highly variable among similar communities,
 and a weak indicator of latitudinal biodiversity trends. They are
 inconsistently related to the parameters of key models that might underlie
 count distributions, and they vary highly in simulation even when these
 model parameters do not vary. Ecologists would benefit by instead
 determining which real distributions fit which theoretical models and
 using estimated parameters to understand community structure and assembly.
description: The gzipped Ecological Register data file
 (Ecological_Register_data.txt.gz) is a full set of published species
 inventories of trees and terrestrial animals downloaded from the
 Ecological Register website on 23 October 2022. The additional files
 include metadata pertaining to the references used to document the
 inventories (Ecological_Register_references.txt.gz) and to the species
 inventories themselves (Ecological_Register_samples.txt.gz) .The gzipped
 and tarred richness R library (richness.tar.gz) was used to prepare the
 data and analyses in a preprint of an earlier paper called "Three
 models of ecological community assembly". The blank cells in the .txt
 files represent cases where no data were entered into the relevant fields,
 and will be interpreted as NAs when uploaded by an R script. There are no
 hidden values.
description: The R programming environment is required to open the richness
 library and the scripts.
description: # Ecological Register Dataset --- This file includes all species
 inventories downloaded from the Ecological Register on 23 October 2022. ##
 Description of the data and file structure Ecological_Register_data.txt.gz
 is a single self-contained, tab delimited data matrix including a header
 that describes the data columns. The file is a list of species occurrences
 within species inventories. The reference.no field points to a list of
 references to publications in the Ecological_Register_references.txt.gz
 file. The sample no field points to a table with additional species
 inventory metadata to be found in the Ecological_Register_samples.txt.gz
 file. The blank cells in the files represent cases where no data were
 entered into the relevant fields, and will be interpreted as NAs when
 uploaded by an R script. There are no hidden values. ## Sharing/Access
 information The Ecological Register website is at
 [http://ecoregister.org](http://ecoregister.org). ## Code/Software Code
 used in the paper "Does evenness even exist?" is reposited on
 Zenodo (https://doi.org/10.5281/zenodo.15762247). The underlying code used
 to run the analyses of the preprint "Three models of ecological
 community assembly" is in the richness.tar.gz file that includes the
 R library called richness. The current version of the richness package is
 at https://github.com/johnalroy/richness/releases. The code used to
 prepare the figures, tables, and individual statistics reported in the
 text of "Three models" is included in the script called
 three_models.R.