Translating the name "EOL"
You can choose either, and the trick is to find the biggest community to reach an agreement on whether to translate. If the Czech community on Encyclopedia of Life is not very big, perhaps you could discuss on the Czech wikipedia, with links from the Portal:Cs. Do they have language community pages on EOL?
A related issue is whether to change the abbreviation EOL.
A quick review of the EOL home page shows that most, but not all, language verions have translated the name (in the header 'Currently in the Encyclopedia of Life' towards the bottom of the page). Most, but not all, have left the acronym EOL as it is. In all cases, the logo EOL with Encyclopedia of Life underneath it, stays in English.
No Czech community pages on OEL, no website on the Czech wikipedia yet. Well, this will surely change once the EOL communicates also in Czech language. Until then I will use the original EOL acronym.