Is biodiversity good for human wellbeing?

I was interested to see on the BBC News site that a link has been shown between biodiversity and human wellbeing. It seems widely accepted that exposure to the countryside is good for most people's wellbeing (though some can't stand it, and I wouldn't want to perpetrate a lazy stereotype), but biodiversity is a whole different kettle of fish. Nonetheless here's a direct quote of the subtitle of the piece on the BBC site:

Scientists need to capitalise on a growing body of evidence showing a link between biodiversity and human wellbeing, a US review has suggested.

Now, there are several issues here. Luckily (and sadly rarely), the original review paper 'Exploring connections among nature, biodiversity, ecosystem services, and human health and well-being: Opportunities to enhance health and biodiversity conservation' (snappy title) is open source and you can read it here for free.

I have three issues:

1. What is wellbeing? I am currently reading for review a book on happiness and it makes it clear that most existing studies miss significant aspects of what happiness is, and don't properly understand the nature of what makes us happy/gives us wellbeing. As far as I can see, in the review paper there is no attempt to qualify what was being measured as 'wellbeing' and whether the studies were all measuring the same thing.
2. The review paper doesn't describe a link between biodiversity and wellbeing. It shows links between being exposed to nature and wellbeing, and says that there may be health benefits from being exposed to biodiversity in bacteria. But it says nothing useful about whether, say, the number of newt species reducing from 15 to 14 (that isn't a fact, it's just to give a feel for what reducing biodiversity means) has any effect on wellbeing. My suspicion is that it doesn't - that the benefit (leaving aside the bacteria/health aspect) is purely from being out in nice countryside or a park, rather than how biodiverse that habitat is. But more to the point, the paper does not show the specific link claimed by the BBC article. The paper actually says 'Thus, with one major exception discussed here, the actual roles of biodiversity in promoting human health and well-being remain largely uncertain.' And that one exception is on bacteria and health, not general biodiversity and wellbeing.
3. What is the natural world? I found the review paper's definition confused. They start by saying 'We used the generally accepted definition of nature as the physical and biological world not manufactured or developed by people.' Yet later on then say 'contact with nature (broadly defined in the introduction and including urban green space, parks, forests, etc.)' So they appear  to be unaware that parks were developed by people. As frankly is almost all the countryside in the UK. This is confusing, to say the least.

Don't get me wrong. I am very happy to go along with the idea that exposure to nature improves the wellbeing of many people. And I am all in favour of biodiversity (though we do need to realise that there have always been changes in species populations, and we shouldn't try to preserve nature in aspic). But claiming that there is a link between biodiversity and human wellbeing seems to me to be a clear distortion of the science.