I feel kind of bad, because I look at that picture and it just looks like a grassland with a couple of funny-looking trees in it. Having lived in a swamp for half my life, there isn't that GREENNESS I get when I go back home. Humid, muggy areas are typically REALLY lush. The hanging vines from the trees are a start, but you could honestly make the grass twice as tall and choke up the waters with more plants.
I can totally hear insects buzzing, though. That kind of ambiance is vital for any swamp/jungle area.