With its glaciers and volcanoes, Iceland is sometimes called “the land of fire and ice”, but it should really be called “the land of waterfalls”. There are some truly spectacular ones there, many of them quite famous. I’m not sure how far you’ll be willing to travel, but Seljalandsfoss is a great one.
For wildlife, Iceland doesn’t have any forests, exactly (Icelandic joke: “What do you do if you’re lost in a forest in Iceland?” “Stand up.”), mostly tundra and barren volcanic wasteland. So be sure to bring a macro lens or camera able to get closeups of arctic plants, if there are any not buried under snow that early in the year. For animals, you might want to plan to visit a good spot for viewing seabirds.