Complex sentence: Garden dormice are often found in the Alps, in the Bavarian Forest, in the Ore Mountains, and on rare occasions, in northern Germany, which apparently has a population not capable of large-scale reproduction.
Split into simpler sentences: Garden dormice are often found in the Alps, in the Bavarian Forest, and in the Ore Mountains. The species is also present in northern Germany, but the population there is apparently not capable of large-scale reproduction.