Disaggregating the evidence linking biodiversity and ecosystem services

Ecosystem services (ES) are an increasingly popular policy framework for connecting biodiversity with human well-being. These efforts typically assume that biodiversity and ES covary, but the relationship between them remains remarkably unclear. Here we analyse >500 recent papers and show that reported relationships differ among ES, methods of measuring biodiversity and ES, and three different approaches to linking them (spatial correlations, management comparisons and functional experiments). For spatial correlations, biodiversity relates more strongly to measures of ES supply than to resulting human benefits. For management comparisons, biodiversity of ‘service providers' predicts ES more often than biodiversity of functionally unrelated taxa, but the opposite is true for spatial correlations. Functional experiments occur at smaller spatial scales than management and spatial studies, which show contrasting responses to scale. Our results illuminate the varying dynamics relating biodiversity to ES, and show the importance of matching management efforts to the most relevant scientific evidence.

The methods, validity of approach, statistical inference (though limited), and quality of the presentation are quite good. Indeed, this version is markedly improved over the last.
The paper is well written, its conclusions more robust than in its previous iteration.
I have no particular comments to add since I provided substantial commentary for the first revision and the authors have addressed all of them as best they can. Certain issues remain, such as the somewhat unclear motivation, fuzzy implications, and masked limitations (and strengths) of scientific research that the coding process engenders. I don't think managers, for example, benefit from this -they want clear and plain guidelines, whereas this is a cautionary note that requires managers to figure out how best to use the information. Also, the field evolves. But every study of this nature will find no way around these problems and I think the authors have done a genuine and sincere effort to present their case in the most robust fashion they can.
I strongly support the study. It is an important contribution to the field.

Response to Reviewers
We appreciate the final review comments from Reviewer #1. We've pasted those comments below, with very brief responses in all caps.

Reviewer #1 (Remarks to the Author):
This manuscript is a revised version of a previous submission concerning the relationship between biodiversity and ecosystem functions and or services. The approach is a structured literature review; a meta-analysis of sorts. Its findings are that the relationship, though more or less positive, is sensitive to issues such as scale, the particular service, and the nature of the study (i.e., was it experimental or observational). Its conclusions do not bear on the science, per se, but it does provide a synopsis of the state of the body of research (as sampled and structured by the authors methodology) and cautions about matching management objectives with properties of the research it references.
The methods, validity of approach, statistical inference (though limited), and quality of the presentation are quite good. Indeed, this version is markedly improved over the last. THANK YOU.
The paper is well written, its conclusions more robust than in its previous iteration.

AGAIN, THANKS AND GOOD TO HEAR.
I have no particular comments to add since I provided substantial commentary for the first revision and the authors have addressed all of them as best they can. Certain issues remain, such as the somewhat unclear motivation, fuzzy implications, and masked limitations (and strengths) of scientific research that the coding process engenders. I don't think managers, for example, benefit from this -they want clear and plain guidelines, whereas this is a cautionary note that requires managers to figure out how best to use the information. Also, the field evolves. But every study of this nature will find no way around these problems and I think the authors have done a genuine and sincere effort to present their case in the most robust fashion they can. I strongly support the study. It is an important contribution to the field.

WE AGREE WITH THE UNIVERSAL LIMITATIONS OF CONDUCTING A STUDY OF THIS KIND. AND WE APPRECIATE YOUR HELP IN MAKING OURS AS STRONG AS IT CAN BE.
Sincerely, Taylor Ricketts