The layers (let’s call it absolute positioned) can be brought into the flow of the page by declaring position in percentage (screencast link below).
An absolute positioned item is either the lowest or the highest part of your page-construction (you can’t smuggle them somewhere in between).
In your case the ivy would be the top item (highest z-index) of all items - right?
And there we are:
The current width of this item is 309px. The entire screen of a mobile portrait mode is 320px. So it would cover all and everything, each link and stuff below. This could be re-arranged by simply display:none for all critical device-widths. But hey - not display an important part of the page for one part of the audience? Hm - perhaps it isn’t an important one? Who knows!
*It may sound hard, but responsive means first to change the entire attitude towards web these days. It’s about construction, content, semantic and performance.
The shown example is excellent for a brochure (folder, flyer however you call it) - but not for web 2014. It’s about visual, feel and look (images are not content - just decoration) - things that are secondary or even redundant.