EstimateS is a free software application for Windows and Macintosh operating systems that computes a variety of biodiversity functions, estimators, and indices based on biotic sampling data. Some features require species relative abundance data, others only species presence/absence data. A comprehensive User's Guide is available online at this site.
Rarefaction and species accumulation curves
- Computes expected species accumulation curves (sample-based rarefaction curves in the terminology of Gotelli & Colwell 2000), with 95% confidence intervals, using the analytical formulas of Colwell & Mao (2004). This method is a precise equivalent of, and completely replaces the resampling technique used in previous versions of EsimateS for computing these curves. (Resampling is still used to compute richness estimators for accumulating samples.)
- Computes individual-based rarefaction curves (Coleman curves) for sample-based abundance data.
Species richness estimators and diversity indices
- Computes non-parametric species richness estimators for abundance-based data (Chao 1 and ACE) and for sample-based data (Chao2, ICE, first and second order Jackknives, and Bootstrap).
- For Chao1 and Chao 2, computes log-linear confidence intervals.
- Computes a species richness estimator based on fitting an asymptotic function (the Michaelis-Menten equation) to the sample-based rarefaction curve.
- Computes Shannon, Simpson, and Fisher's alpha diversity indices (if this option is checked).
Shared species estimation and biotic similarity indices, with estimators
- Computes Chao's estimator of total shared species (including observed and unseen shared species) for sample pairs.
- Computes classic Sørensen and Jaccard similarity indices for sample pairs based on incidence (presence-absence) or abundance data sets
- Computes Chao's abundance-based Sørensen and Jaccard similarity indices, with statisically rigorous estimators and their standard errors, for sample pairs based on abundance or on replicated incidence (presence-absence) data sets.
- Computes Morisita-Horn and Bray-Curtis (= "Sørensen quantitative") similarity indices for sample pairs based on abundance data sets.
Importing data and exporting results
- For input, accepts tab-delimited, plain text files (produced by programs such as Excel, using "Save As Tab-delimited Text"), in either of two matrix formats (species-by-sample or , sample-by-species) or either of two "triplet" formats ([species index, sample index, value]; or [sample index, species index, value]).
- For input, accepts pre-formatted sample-by-species matrices exported by Biota: The Biodiversity Database Manager.
- Exports all results as tab-delimited text files, easily opened in Excel, statistical, or graphing applications.
- As an option, records and exports results from n individual randomizations to a text file, allowing computation of precision, accuracy, and other analyses (Walther and Moore 2005), using Excel or other applications.
Two versions of EstimateS are currently offered, to allow users with older operating systems to continue using EstimateS. Unless you need to use Version 7.5.2 for this reason, Version 8.0.0 is recommended. All known bugs are corrected in both versions.
- EstimateS800Win runs native under Microsoft Windows XP, is certified back to Windows 2000, but will not run under Windows 98 or Windows Millenium.
- EstimateS752Win runs under operating systems from Windows XP back to Windows 2000, but may also work under even earlier operating systems.
- EstimateS800Mac runs native under Mac OS X (certified up to 10.4). It will not run under Mac OS 9.
- EstimateS752Mac runs native under Mac OS X (certified up to 10.3), or under Mac OS 9.1 or 9.2 with CarbonLib 1.4 or later installed. You can download CarbonLib for free from Apple.
Between 1997 and 2006, EstimateS was downloaded by more than 20,000 users in more than 100 countries around the globe. They use EstS in conservation biology, biotic inventories, natural area assesssment and monitoring, biogeography, macroecology, microbial ecology, molecular biology, ethnobotany and many other fields. You can get an idea of the diversity of uses by scanning the titles of the references that appear below.
As of July, 2004, a total of 237 publications are known to have cited EstimateS. If have cited EstS in a published work that is not in the list, and you would be willing to have it included, please contact Robert K. Colwell with details. Click here for the list of publications. (This list will be periodically updated.)