Here is the new Monthly Shooting Assignment Jan/Feb 2016.
Not only real traces of people, but all signs of human life are welcome.
Such as, for example traces of use, things or discarded things in nature, a trap or fishing net, pregnancy, lights in the distance, etc.
An abstract approach, creativity, good composition and good quality of lighting are extra pluses. Good luck!!!
Monthly Shooting Assignment Guidelines:
http://www.apug.org/forums/forum195/142453-monthly-shooting-assignment-msa-guidelines-revised-2015-07-a.html