The authors basically answered all questions or suggestions concerned by the two reviewers. The manuscript will not be sent back to reviewers, but there are still some minor changes which are needed:

1). As reviewer 2 pointed out that errors or uncertainties are very important, the authors are asked to add one small paragraph at the end of the section 5.1 to summarize all potential errors or uncertainties from this study.

2). p15, second line from the bottom: In the reply letter to the editor, the authors said that they used images from 2008, while in the text, it says using the images from 2005. Which one is correct?

3). p23, add "with uncertainty of 10 km2 or about 9%" after the first sentence of the first bullet point.

4). p23, the first sentence of the second bullet: change "at all study areas" into "at the four study areas" if this is what you are talking about. Otherwsie, it can be very easily confused or misleading.

5). p23, line 23: Is it possible that the authors provide a rough error bar for the 100 km2 decrease in area?