Iraq, for many of us, is an unimaginable place. Our experience of it is through the far end of a CNN camera: a desert across which camouflaged Humvees race between crumbling and bombed-out cities. There is, unfortunately, all that. But Iraq, like everywhere else, has its own particulars of ecology: the alluvial plains of the Tigris and Euphrates, the marshlands of the south, the northern highlands and mountains near the Turkish border.