A lot of German Jews fought and died for the Kaiser during WWI. Did the Nazis do anything to the graves of Jewish veterans in German military cemeteries after they took power?

Hello there ^^

Germany, as opposed to nations like the USA, has no tradition of dedicated military cemetaries. Instead, most soldiers are buried in their hometown, while others (whose bodies could not be retrieved for various reasons) are buried at the front cemetaries in Belgium, France, Poland etc.

This of course means that the largest amount of Jewish veterans were buried in Jewish graveyards, which, as you may guess, were objects of vandalism during the Nazi regime, although a large portion survived. After the war, the graves of soldiers were legally put under the maintainance of their respective towns, meaning that they are maintained regardless of their location. Of the Jewish graveyards, some were continually used by the Jewish communities, but the majority are more or less abandoned.

Information regarding graves in Germany might be a bit of a difficult thing :P regulations vary across state lines. Mostly, each town maintains a plain list of graves in its jurisdiction, nothing more. If your ancestors are buried in Germany, it'd be good if you know which town they come from to get a rough starting point for research. For graves outside of Germany, the People's Federation for War Grave Maintainance has been doing a list of their own. They actually even have an online search (http://www.volksbund.de/en/graebersuche.html), although its not exhaustive.