/// <summary>
/// Get species observation count.
/// </summary>
/// <returns>species observation count.</returns>
public Int64 GetSpeciesObservationCount()
{
GbifDataSetsJson page = GetSpeciesObservationPage(0, 0);
if (page.IsNull())
{
throw new ApplicationException("Faild to retrieve species observation count.");
}
return(page.Count);
}