In order to be successful in AP Environmental Science (APES), you will need to have a strong grasp on biology and chemistry at a minimum. You do not "need" to be familiar with physics in order to be successful in APES, but if you are familiar with physics as well you will have a much easier time understanding some of the concepts involved in the course. It is also necessary that you feel comfortable with algebra and especially dimensional analysis from a math standpoint.
Concepts in APES are not necessarily "harder" than you may be used to in a typical science class, but the sheer amount of concepts and pace that they must be learned at makes the course a challenge for many students. Because of the amount of information involved with APES and the background knowledge necessary to be successful, you should already have chapter 2 from the textbook read and objectives completed even before the course begins. You will "hit the ground running" from day one! As the year goes on, you should expect approximately two hours of work outside of class for every one hour of work during class. This means that for every 90 minute class, there will be up to 3 hours of work outside of class. This is a college level course that covers an immense amount of material!
At the beginning of each unit, you will be given a list of objectives and a variety of resources to help you meet these objectives. You will also have access to a digital textbook during the year. Since you will not have access to the digital text until the start of the semester, you may use a scanned copy of the chapter which may be downloaded here. The objectives for the unit that should be completed over the summer can be found here. If you would like an overview of the unit or something to take notes on during your reading, you may wish to use the presentation notes for this unit which may be found here. The chapter test for the summer work will be given on the second day of classes.
The first new concept that you will learn about in class is that of sustainability. Most students have an idea of what they think this means, but the concept of sustainability entails quite a bit more than what you may be thinking. Wisconsin Public Television put out a great talk on sustainability by Paul Robbins who is the director of the Nelson Institute for Environmental Studies. It is highly recommended that you watch this video as an AP Environmental Science (APES) student. The video may be found at the link below.