This image of an ecotone is on the south edge of our "dry woods/brush" habitat, with a fairly abrupt change to grassland, and I thought of it because of what JuliaB said--she will remember that the grass used to be bare, compacted (heavily trampled by cattle and baked into pottery-like cups and dishes--hard to walk on). Water seeps out of the ground here after long rain events, pooling in the "dry woods swale (to the right, and pictured elsewhere in the Habitats gallery.)
When we had the family of gray foxes, this area was a favorite place for the vixen to bring her cubs--they learned to hunt chasing grasshoppers out here. The roadrunner likes this area too--plenty of grasshopper and lizard prey. Both used the dry woods for cover and additional hunting area. The coyote we have now checks this out regularly, as do the winter raptors. Deer bed down in one particular area, though not as much since the coyote moved in to replace the foxes (they died of feline distemper.) In winter, mowed closer than usual, this is a favorite spot for some of the winter migrants--it's sunny, often out of the wind, and there's cover nearby if needed. Dragonflies use the tree margin for resting/sleeping cover, and fly out directly over the grassland to hunt. Around the margins of the dry woods--the other two sides of the parallelogram that juts off the north fenceline--we've found more little microhabitats than you might expect.
Ecotone...fascinating place.