Interesting article, although I am not sure I completely agree with Dr. Mendelson's assertions. Habitat loss undoubtedly contributes greatly to species extinctions around the world, and I do agree with him that habitat loss is certainly not the only cause for extinction. But because there are multiple causes, does that mean that the impact of habitat loss is that much less? Not at all.
Similarly, you could make the same argument about chytrid. Amphibian decline and chytrid are synonymous. Amphibians are globally threatened, but is chytrid as big an issue as the current research suggests? I don't mean to say that it's not a serious issue, but if you looked at the amount of literature in the last year on chytrid versus climate change versus habitat loss versus harvest and so on, chytrid is the overwhelming victor. But does it really represent that big of a threat?
I think that the big problem is that extinction and its causes are a very complex topic, and to identify and tackle all of them, it would be logistic nightmare and would likely spread resources thin for conservation efforts.