What is MPower?
MPower is a user-friendly program for determining which null model tests in the application EcoSim (Gotelli and Entsminger 2007) are reliable for analyzing your ecological data. MPower is key for ensuring that you draw accurate inferences from your ecological data.
Obtaining MPower
MPower is free for download. It runs on the Windows operating system, and the entire download is less than 6Mb.
Using MPower
MPower requires no installation -- simply unzip the downloaded file and click the MPower icon to run. MPower comes with extensive help files, including a tutorial. Click Help on your copy of MPower to begin accessing these features.
Citing MPower
Ladau, J. and Ryan, S.J. 2010. MPowering ecologists: community assembly tools for community assembly rules. Oikos 119(7): p. 1064-1069 [PDF]
MPower is a user-friendly program for determining which null model tests in the application EcoSim (Gotelli and Entsminger 2007) are reliable for analyzing your ecological data. MPower is key for ensuring that you draw accurate inferences from your ecological data.
Obtaining MPower
MPower is free for download. It runs on the Windows operating system, and the entire download is less than 6Mb.
Using MPower
MPower requires no installation -- simply unzip the downloaded file and click the MPower icon to run. MPower comes with extensive help files, including a tutorial. Click Help on your copy of MPower to begin accessing these features.
Citing MPower
Ladau, J. and Ryan, S.J. 2010. MPowering ecologists: community assembly tools for community assembly rules. Oikos 119(7): p. 1064-1069 [PDF]
To use MPower, follow these steps:
- Open MPower. Check that EcoSim700.exe is in a folder named "EcoSim" next to MPower. Make sure that the Ecosim temp file is also in the folder.
- Select a null hypothesis that you are interested in testing.
- Select assumptions that are reasonable for your data set. If no assumptions are reasonable, then leave all assumptions unchecked
- Choose a hypothesis test that you are considering using.
- Enter the dimensions of the presence-absence matrix that you wish to analyze.
- Click "Run." Depending on the options that you select, the analysis may take some time. To display EcoSim, click the "Show EcoSim" box.
- Examine the results. If the test is suitable for your circumstances, then "*****Test has tolerable Type I error rates.*****" will be displayed in the "Type I Error Rates" section, and "*****Test has adequate power.*****" will be displayed in the "Type II Error Rates" section. Otherwise, warning messages will be displayed.
- Save the results or click "Close" to return to the initial window.
| mpower.zip |
NOTE: Currently, MPower allows you to analyze null model tests of co-occurrence patterns, but future versions will be able to analyze additional types of null model tests.
Null model tests of co-occurrence patterns employ presence-absence data. These data consist of lists of species observed at sites. The sites may be islands, quadrats, lakes, etc (e.g., Krasnov et al 2006, Gotelli and McCabe 2002). The data are often summarized in a presence-absence matrix, in which rows represent species and columns represent sites. If a species was observed at a particular site, 1 is entered in the corresponding cell of the matrix; otherwise 0 is entered. Null model tests of co-occurrence patterns were originally introduced as tools to check whether competition affects co-occurrence patterns of species (Connor and Simberloff 1979). However, they may also be used to check if other interactions are influential, species are distributed "randomly," sites are ecologically equivalent, or species have similar niches (e.g., Gotelli and McCabe 2002).
Null model tests of co-occurrence patterns employ presence-absence data. These data consist of lists of species observed at sites. The sites may be islands, quadrats, lakes, etc (e.g., Krasnov et al 2006, Gotelli and McCabe 2002). The data are often summarized in a presence-absence matrix, in which rows represent species and columns represent sites. If a species was observed at a particular site, 1 is entered in the corresponding cell of the matrix; otherwise 0 is entered. Null model tests of co-occurrence patterns were originally introduced as tools to check whether competition affects co-occurrence patterns of species (Connor and Simberloff 1979). However, they may also be used to check if other interactions are influential, species are distributed "randomly," sites are ecologically equivalent, or species have similar niches (e.g., Gotelli and McCabe 2002).