You still have to know everything on the list (which includes ecology). As broad as that sounds, I would try to cover it all.
You might not get questions on the real DAT about it though...
I got 1 question in Taxonomy and no Ecology. But it is better to be prepared because those questions are usually very easy and strait forward, you don't want to get them wrong simply because you didn't read those two pages from Kaplan or whatever book you are using.