This depends on your status. As a nonprofit or professional, you just need to declare the amount received the way you normally would in your accounting for any type of sale or services provided.
If you are an individual, it depends of the local legislation of the country you live in and pay taxes. Usually tax authorities consider that any type of income must be declared, wherever it comes from. So make sure that you are in accordance with law when declaring income obtained though crowdfunding on Ulule.