Ensuring carbon offset systems protect biodiversity

In a recent submission to the federal government on Canada's Offset System for Greenhouse Gases, I proposed that all offset projects should be subject to a test for their effect on species listed under the federal Species At Risk Act.

I had been trying to come up with a test to ensure biodiversity benefits. We liked this idea because it was simple and consistent with an existing federal statute. I'm curious if anyone else has any thoughts on this idea or any information on other approaches being promoted elsewhere.

I know of a couple of other possible approaches:

1. The Forestry Protocol under the California Climate Change Action Registry only allows conservation, conservation-based forestry and restoration as eligible projects. This approach ensures biodiversity benefits by restricting project types.

2. The Climate, Community and Biodiversity Alliance also propose a species at risk test in their standard for assessing land-based carbon offset projects, but they also have a more general requirement of net positive biodiversity impacts. It seemed to me that the transaction costs of this approach might be too high.... would it be feasible to measure biodiversity benefits broadly?
...does anyone have any experience with this approach or knowledge of how this has been implemented?

3. In a draft forest management protocol developed for use (but not approved) within the Alberta Offset System, it was required that offset project activities not adversely affect biodiversity targets developed by forest managers. Certification to third-party forest management certification systems was also suggested.

4. The Clean Development Mechanism under the Kyoto Protocol require an evaluation of environmental impacts and an environmental assessment may be required.

What do you think? It would be great to hear your feedback. Thanks.