Composition is something that is critical to study. The OP's comments relate primarily to conveying a sense of the swamp. The responses relate to composition, primarily. Good composition helps to convey a message or feeling in an pleasing way, but -how- you convey something in terms of composition is not the same thing as the sense you are trying to convey.
That said, at this point if you don't have a good sense of why Range 2 is compositionally better, it would be useful to find some books and tutorials on composition. Horse Range 1 shows very poor composition. The superior composition of Range 2 is what people are responding to. Until an image "works" compositionally, it can't succeed in terms of being emotionally emotive. Sometimes one needs to break normal rules of composition in order to make an image work, but Range 1 wasn't an example.
The multiple S curves in Range 2 as well as the loose adherence to the rule of thirds make it dynamic and pleasing to the eye.
In terms of photography and attempting to convey a sense of the swamp, I would look to accentuate the water and leaves. I would put on hip waders and bring my camera and tripod right to the water so my lens was not much more than a foot at the most, above the water. Before doing so I would walk around at the edge of the swamp as close as possible to previsualize the final image.
I did the same thing I am espousing in this shot, where I brought the camera down reasonably low, and as close to the water as I could to add the foreground I wanted.
I am sure there are dozens of ways to convey a sense of the swamp but they all start with understanding composition. Grab a wide angle, walk around looking straight up (occasionally

). Seeing involves looking, and looking. gluck
BTW...yeah...I understand the following image breaks many rules of composition. No problem.

http://www.pbase.com/santa/image/49293707/large.jpg