1. Species distribution models (SDMs) for presence-only data depend on accurate and precise measurements of geographic and environmental covariates that influence presence and abundance of the species. Some data sets, however, may contain both systematic and random errors in the recorded location of the species. Environmental covariates at the recorded location may differ from those at the true location and result in biased parameter estimates and predictions from SDMs. 2. Regression calibration is a well-developed statistical method that can be used to correct the bias in estimated coefficients and predictions from SDMs when the recorded geographic location differ from the true location for some, but not all locations. We expand the application of regression calibration methods to SDMs and provide illustrative examples using simulated data and opportunistic records of whooping cranes (Grus americana). 3. We found we were able to successfully correct the bias in our SDM parameters estimated from simulated data and opportunistic records of whooping cranes using regression calibration. 4. When modeling species distributions with data that have geographic location errors, we recommend researchers consider the effect of location errors. Correcting for location errors requires that at least a portion of the data have locations recorded without error. Bias correction can result in an increase in variance; this increase in variance should be considered when evaluating the utility of bias correction.
Exact 100m
The file ‘Exact 100m.csv’ includes environmental covariates calculated within a 100 m radius buffer around the 32 whooping crane group locations obtained with a global positioning system as well as within a 100 m radius buffer around the 10,000 Monte Carlo integration points used in the analysis. The column ‘presence.location’ indicates if the covariates are associated with a location of a whooping crane group (yes) or a Monte Carlo integration point (no). Columns ‘aquatic’ and ‘development’ represent the proportion of aquatic habitat and development within a 100 m radius buffer around the whooping crane group locations and the Monte Carlo integration points. Columns ‘aquatic.section’ and ‘development.section’ represent the proportion of aquatic habitat and development within a 100 m radius buffer around whooping crane group locations that were degraded in accuracy to the section level and the Monte Carlo integration points. Columns ‘aquatic.small’ and ‘development.small’ represent the proportion of aquatic habitat and development within a 100 m radius buffer around whooping crane group locations that included a small degradation (σ = 100 m) in location accuracy and the Monte Carlo integration points. Columns ‘aquatic.large’ and ‘development.large’ represent the proportion of aquatic habitat and development within a 100 m radius buffer around whooping crane group locations that included a large degradation (σ = 1000 m) in location accuracy and the Monte Carlo integration points. The accuracies of the 10,000 Monte Carlo integration points were not degraded and thus the proportion of aquatic habitat and development within the 100 m radius buffers are the same across respective columns. Note: the same 10,000 Monte Carlo integration points were used in all analyses.
Exact 250m
The file ‘Exact 250m.csv’ includes environmental covariates calculated within a 250 m radius buffer around the 32 whooping crane group locations obtained with a global positioning system as well as within a 250 m radius buffer around the 10,000 Monte Carlo integration points used in the analysis. The column ‘presence.location’ indicates if the covariates are associated with a location of a whooping crane group (yes) or a Monte Carlo integration point (no). Columns ‘aquatic’ and ‘development’ represent the proportion of aquatic habitat and development within a 250 m radius buffer around the whooping crane group locations and the Monte Carlo integration points. Columns ‘aquatic.section’ and ‘development.section’ represent the proportion of aquatic habitat and development within a 250 m radius buffer around whooping crane group locations that were degraded in accuracy to the section level and the Monte Carlo integration points. Columns ‘aquatic.small’ and ‘development.small’ represent the proportion of aquatic habitat and development within a 250 m radius buffer around whooping crane group locations that included a small degradation (σ = 100 m) in location accuracy and the Monte Carlo integration points. Columns ‘aquatic.large’ and ‘development.large’ represent the proportion of aquatic habitat and development within a 250 m radius buffer around whooping crane group locations that included a large degradation (σ = 1000 m) in location accuracy and the Monte Carlo integration points. The accuracies of the 10,000 Monte Carlo integration points were not degraded and thus the proportion of aquatic habitat and development within the 250 m radius buffers are the same across respective columns. Note: the same 10,000 Monte Carlo integration points were used in all analyses.
Exact 500m
The file ‘Exact 500m.csv’ includes environmental covariates calculated within a 500 m radius buffer around the 32 whooping crane group locations obtained with a global positioning system as well as within a 500 m radius buffer around the 10,000 Monte Carlo integration points used in the analysis. The column ‘presence.location’ indicates if the covariates are associated with a location of a whooping crane group (yes) or a Monte Carlo integration point (no). Columns ‘aquatic’ and ‘development’ represent the proportion of aquatic habitat and development within a 500 m radius buffer around the whooping crane group locations and the Monte Carlo integration points. Columns ‘aquatic.section’ and ‘development.section’ represent the proportion of aquatic habitat and development within a 500 m radius buffer around whooping crane group locations that were degraded in accuracy to the section level and the Monte Carlo integration points. Columns ‘aquatic.small’ and ‘development.small’ represent the proportion of aquatic habitat and development within a 500 m radius buffer around whooping crane group locations that included a small degradation (σ = 100 m) in location accuracy and the Monte Carlo integration points. Columns ‘aquatic.large’ and ‘development.large’ represent the proportion of aquatic habitat and development within a 500 m radius buffer around whooping crane group locations that included a large degradation (σ = 1000 m) in location accuracy and the Monte Carlo integration points. The accuracies of the 10,000 Monte Carlo integration points were not degraded and thus the proportion of aquatic habitat and development within the 500 m radius buffers are the same across respective columns. Note: the same 10,000 Monte Carlo integration points were used in all analyses.
Full 100m
The file ‘Full 100m.csv’ includes environmental covariates calculated within a 100 m radius buffer around the 32 whooping crane group locations obtained with a global positioning system, the 36 locations that were recorded as the center the Public Land Survey System section, and the 10,000 Monte Carlo integration points. The column ‘presence.location’ indicates if the covariates are associated with a location of a whooping crane group (yes) or a Monte Carlo integration point (no). Columns ‘aquatic’ and ‘development’ represent the proportion of aquatic habitat and development within a 100 m radius buffer around whooping crane group locations and Monte Carlo integration points. The column ‘accuracy’ indicates if the location was recorded as the center of a Public Land Survey System section (section) or if the location was recorded with a global positioning system (gps). The location of the 10,000 Monte Carlo integration points were recorded without error and therefore the ‘accuracy’ is recorded as exact. Note: the same 10,000 Monte Carlo integration points were used in all analyses.
Full 250m
The file ‘Full 250m.csv’ includes environmental covariates calculated within a 250 m radius buffer around the 32 whooping crane group locations obtained with a global positioning system, the 36 locations that were recorded as the center the Public Land Survey System section, and the 10,000 Monte Carlo integration points. The column ‘presence.location’ indicates if the covariates are associated with a location of a whooping crane group (yes) or a Monte Carlo integration point (no). Columns ‘aquatic’ and ‘development’ represent the proportion of aquatic habitat and development within a 250 m radius buffer around whooping crane group locations and Monte Carlo integration points. The column ‘accuracy’ indicates if the location was recorded as the center of a Public Land Survey System section (section) or if the location was recorded with a global positioning system (gps). The location of the 10,000 Monte Carlo integration points were recorded without error and therefore the ‘accuracy’ is recorded as exact. Note: the same 10,000 Monte Carlo integration points were used in all analyses.
Full 500m
The file ‘Full 500m.csv’ includes environmental covariates calculated within a 500 m radius buffer around the 32 whooping crane group locations obtained with a global positioning system, the 36 locations that were recorded as the center the Public Land Survey System section, and the 10,000 Monte Carlo integration points. The column ‘presence.location’ indicates if the covariates are associated with a location of a whooping crane group (yes) or a Monte Carlo integration point (no). Columns ‘aquatic’ and ‘development’ represent the proportion of aquatic habitat and development within a 500 m radius buffer around whooping crane group locations and Monte Carlo integration points. The column ‘accuracy’ indicates if the location was recorded as the center of a Public Land Survey System section (section) or if the location was recorded with a global positioning system (gps). The location of the 10,000 Monte Carlo integration points were recorded without error and therefore the ‘accuracy’ is recorded as exact. Note: the same 10,000 Monte Carlo integration points were used in all analyses.
Whooping crane location data
The file ‘Whooping crane location data.csv’ contains 68 whooping crane group locations that were obtained opportunistically in Nebraska, USA from 2000‒2012. The file contains latitude, longitude, and accuracy of each location. The column ‘accuracy’ indicates if the location was recorded as the center of a Public Land Survey System section (section) or if the location was recorded with a global positioning system (gps).
