As dunes are completely made up of the gypsum, they have beautiful white color.
The dunes in the inner part of the field are much starker. They have few plants, and less animals. There is virtually no water in the dune field, so all animals depend ultimately on the plants for a source of water. With few to no plants present on the inner dunes, animals cannot live there.
This place is very beautiful, and so very odd looking. I highly recommend a trip there. They say that the best time to go is during the early or late parts of the day. In order to take good photos you need some shadows. Additionally, noon can be very hot. However they do have a nature center in the middle of the park, which may be a very pleasant spot to pass midday in.