Biodiversity. But what is it?

Biodiversity is one of the less well-described aspects of environmental change when it comes to metrics for guiding, enforcing and refining efforts to sustain it

International Biological Diversity Day fell on 22 May in the UN calendar of commemorative days. This decade—until 2020—is the Decade on Biodiversity by the same measure.

Biodiversity is a good thing to call attention to. It helps regulate climate, air, soil, hydrology and other parts of our context that we’d like to keep within habitable ranges. It provides food, fuel, and shelter and maintains the ongoing supply of such material goods. The diversity within the genetic “portfolio” of the plants and animals around us is an important source of insurance against the stress of accelerating environmental change. Biodiversity contributes to inspiration, mental health and stress reduction. Pretty much all of the good things in life trace back to biodiversity “ecosystem services” one way or another.

But we need to do more than admire and commemorate it. We need to start measuring biodiversity and its evolution more effectively: comprehensively enough to inform local politics, decision-making, and trade-offs; and comparably enough for enforcing international treaties and targets.

Biodiversity conservation is a cause that people can get behind. Changes in the composition and range of animal, plant and other species are some of the most widely recognized aspects of environmental disruption.

Studies from the Himalayas to the Peruvian altiplano find that alterations in plant and animal patterns are one of the first forms of environmental change that people in rural areas notice. For those of us in the more insulated urban world, the general threat to biodiversity is visible in mainstream media. The perils of letting bees go extinct, for example, have shown up on blogs with titles like “Why Bee Extinction Would Mean The End Of Humanity”. TV shows, school curricula, magazines, and best-selling non-fiction have helped convey findings about species loss from academic science to a wide audience.

The economically damaging and uncomfortable effects of biodiversity loss are visible on political and corporate time-scales. These are not invisible emissions or ephemeral changes in temperature here and there. Biodiversity is more like air quality—there is potential for constructive politics.

We also have an international infrastructure for maintaining biodiversity. The Convention on Biological Diversity (CBD), a legally binding treaty to conserve biodiversity has been in force since 1993. Nearly all countries have ratified it (notably, the US has signed but not ratified).

But we need to be more precise about biodiversity in order to make the most of these institutions. Biodiversity is one of the less well-described aspects of environmental change when it comes to metrics for guiding, enforcing, and refining regional and global efforts to sustain biodiversity. “National biodiversity monitoring programmes differ widely, most data sets are inconsistent, and few data are shared openly,” write A. Skidmore and colleagues in a 2015 comment paper in Nature. National submissions to the CBD are often incomplete: containing information on animals and plants but missing fungi, for example. There are no doubt many reasons that we missed the 2010 CBD targets for halting biodiversity and seem poised to miss the 2020 targets but R. Hill and co-authors identify “delayed feedback and insufficient information flows” as significant factors in a 2015 Global Environmental Change article.

Biodiversity has various dimensions: the number of species represented, the heterogeneity of the species, and the “evenness” with which different species are represented (more concentrated populations with many members of one species and few of another are less “diverse” than ones with less concentration, even if the overall species counts match).

The first, the crudest, is the most commonly available metric. The second and third dimensions, however, are probably the most important for understanding the sustainability of the non-human communities around us. L. Santini and colleagues point out another challenge in their 2016 paper in Biological Conservation: commonly used summary indices for biodiversity offer incommensurate and sometimes inconsistent messages about changes in biodiversity over time. We are flying blind and cross-eyed.

Traditionally structured international efforts to measure biodiversity are moving slowly. The Food and Agriculture Organisation (FAO) of the UN has long recognized the value of biodiversity for food security, but the first report on The State Of The World’s Biodiversity For Food And Agriculture, will only be coming out later this year. The Intergovernmental Platform on Biodiversity and Ecosystem Services , established in 2012 in the hopes of producing a biodiversity equivalent of the Intergovernmental Panel on Climate Change series, had to cut its 2018 budget by a third and postpone three reports after donations from the 126-member nations failed to keep pace with the work programme. Scientific publications on new species have increased since the Global Taxonomy Initiative was initiated in 1998 as part of the CBD, but M. Costello and co-authors in a 2013 Nature article estimate that just 1.5 million of the 5+/- 3 million species on the planet have been named.

New forms of international scientific collaboration, information technology-fuelled citizen science, advances in remote sensing as well as free dissemination of some publicly funded datasets, and a rise in private philanthropic interest are picking up some of the slack. But will these be too little, too late?