The Biodiversity conservation pages at EarthWeb.info focus on general biodiversity issues; specific forms of biodiversity (e.g., insects, orchids, funghi, pandas, etc.) can be found on the Life & taxa pages (🍁🐾 in the main menu).

Where to begin?

A succinct summary that focuses on the term's history and use in international cooperation can be found here.

A status update on global efforts to protect biodiversity can be found here.

(Note that in the climate change arena, there's an obvious "go to" source for a single comprehensive publication explaining the topic. No equivalent exists for the biodiversity arena, where there are literally hundreds of publications that could serve as foundational—so keep in mind that these two suggestions don't have the same foundational character as the IPCC reports.)