Taverna Workbench has a set of default service providers, for example the BioMart services from http://www.biomart.org/biomart/martservice. The Service providers preferences change whether services from such default service providers appear in the Service Panel and whether they can be removed from the panel.
These preferences can be changed by:
Include default service providers controls whether the services from default service providers are loaded into the Services Panel.
Allow permanent removal of default service providers controls whether you can permanently remove the default service providers. If it is disabled, then removing one of the default service providers will only affect your currently running Taverna. When you restart Taverna Workbench then the services from that provider will re-appear.
If you click Help then you will obtain help on this dialog. Reset resets the values to the last applied values. Apply takes the shown values and applies them to Taverna.