Converting IUCN Red List to GeoJSON
Once you have created an account at http://www.iucnredlist.org/ you can download data as shapefiles.
For background see How to convert Shapefiles to GeoJSON maps for use on GitHub (and why you should) and Managing GeoJSON data using GDAL.
IUCN shapefiles can be big, and the resulting GeoJSON can be huge (for example, if a species distribution is based on geographic provinces, and the polygons follow those the geographical boundaries with a high degree of precision).
On a Mac download precompiled GDAL from http://www.kyngchaos.com/software:frameworks and add
export PATH=/Library/Frameworks/GDAL.framework/Programs:$PATH
To .bash_profile
Simply use ogr2ogr:
ogr2ogr -f GeoJson species_13418.geojson species_13418.shp
The GDAL utility ogr2ogr can be used to extract and simplify GeoJSON. For example, given the data for shrimps (FW_SHRIMP) we can extract data for Euryrhynchus amazoniensis like this:
ogr2ogr -f GeoJson Euryrhynchus_amazoniensis.geojson FW_SHRIMP.shp -sql "SELECT * FROM FW_SHRIMP WHERE binomial='Euryrhynchus amazoniensis'" -simplify 0.1
Note the use of -simplify 0.1 to simplify the polygon (without this the file is huge), and the SQL to extract just the data for one species (the species in the dataset are listed din the *.dbf file).