Applied Ecosystem Services, LLC

The Environmental Issues Doctor

Photo of Factors Limiting Species Populations: 1


Estimated reading time: 1 minutes

There are many plant and animal species considered to be threatened, endangered, or of special concern to regulators and the public. Correctly estimating population sizes, relationship to habitats, and potential effects of anthropomorphic activities is crucial to making informed policy and regulatory decisions.

Environmental conditions affecting species populations are the limiting factors. Quantifying limiting factors is fundamental to developing policies and practices that are most likely to create the desired future conditions for the species and its habitats. When limiting factor analyses are incomplete or otherwise flawed policies and regulations are ineffective and result in environmental and economic harm. One reason for ineffective limiting factors analysis is treating biological data the same as more familiar types of continuous data.

The differences between biological data and business, financial, or economic data are important. Biological data require different statistical models and paradigms than those taught in introductory statistics courses.

This work was originally published on the Applied Ecosystem Services, LLC web site at

It is offered under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International license. In short, you may copy and redistribute the material in any medium or format as long as you credit Dr. Richard Shepard as the author. You may not use the material for commercial purposes, and you may not distribute modified versions.

Keep reading

  1. Photo of Factors Limiting Species Populations: 2

    Factors Limiting Species Populations: 2


    Estimated reading time: 2 minutes

    Habitat use is one of the first factors considered when determining limitations on species abundance and distribution. For species being considered for some level of protection there are existing data describing habitats in which they have been found as well as abundance estimates. When projects are proposed in areas with potential habitats for the species it is common to survey these habitats for the species’ presence. The survey methods seek data to answer this question: What is the probability of the species occupying a site if it is not observed during a visit?
  2. Photo of Fit Model to Data

    Fit Model to Data


    Estimated reading time: 2 minutes

    To make informed regulatory decisions it is necessary to understand differences between ecological and environmental data. Analyses of environmental data historically use models adapted from engineering models by numerical ecologists for ecological data collected by academic and research agency scientists. These numeric and statistic models require well-structured data collected to fit assumptions and requirements of the models. This works for researchers who identify a question to be answered and work forward from that to determine when, where, and how much data need collecting to answer that question.

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