Walter Jetz and others have published a paper in Science outlining the need to develop Essential Biodiversity Variables [1]. EBVs facilitate the harmonization of existing monitoring schemes and guide the implementation of new monitoring schemes, especially in gap areas where information on biodiversity change is still very sparse. Examples of essential variables are the allelic diversity of selected wild and domestic species, the population abundance for groups of species representative of some taxa (e.g. birds), the three-dimensional structure of habitats, and the nutrient retention rate in sensitive ecosystems.
References
Essential Biodiversity Variables, Pereira, Henrique Miguel, Ferrier S., Walters M., Geller GN, Jongman RHG, Scholes RJ, Bruford MW, Brummitt N., Butchart SHM, Cardoso AC, et al. , Science, 01/2013, Volume 339, Number 6117, p.277–278, (2013)