What is the version of the following sentence with correct punctuation?

Where a layer of snow previously protected the food found by reindeer and muskoxen during the winter the summers melt water has now caused a crust of ice to form over the vegetation
Where a layer of snow previously protected the food found by reindeer and musk-oxen during the winter, the summer's melt water has now caused a crust of ice to form over the vegetation.