The biodiversity numbers game

How many species are there on Earth? Given the effort required to sample habitats and identify species this figure will likely never been known with great certainty. Indeed current rates of discovery may be slower than the current species extinction rate! To make a start ecologists have thus turned to estimates based on extrapolations of well known patterns in the distribution of species, or the rate of taxonomic discovery. Best estimates vary from as few as 3 million up to 100 million species. A recent paper by Mora et al. (2011, PLoS Biology) has come up with a value of ~8.7 million (+/- 1.3 million) eukaryotic species. This is somewhat lower than the previous best estimates of ~15 million species. The authors base their estimate on the predictable increase in the number of taxa with increasing taxonomic resolution (i.e., from phylum, class, order, family, genera and species). Although the number is likely an underestimate (consider the diversity of microorganisms that remain undiscovered) it is the method that has been criticized. Some experts believe that the patterns upon which the estimates are based are more the reflection of the taxonomic enterprise and have little to do with how many species actually inhabit the Earth. Read the piece in the New York Times about this study.

Turbo Eco-jargon

Language is fluid and ever-changing, and the creation of new scientific terms can be useful if it makes the language more precise, but it also makes our work less accessible for those unfamiliar with specific literature and to the general public. When we start using overly specialised words as a substitute for more commonplace words, it becomes “turbo eco-jargon”.

An example of eco-jargon that works is the term ‘biodiversity’. It shortens ‘biological diversity’ to one word and still retains its meaning. However, most times we create and use terms that are not intuitive and/or not well defined. This can be especially problematic when terms have a common use, but a very specific scientific use, which may also differ among disciplines. Some examples are: stability, productivity, resilience, traits, and function(ing).

I am probably one of the worst in our lab for using eco-jargon (I was actually scolded by an editor once for my use of ‘turbo eco-jargon’ – his exact words!). But I like creating and using highly specialised words because I think they are fun.

Here are a list of some of my long-term favourite turbo eco-terms; how many do you know? (see comments for definitions)

• cursorial
• vagile / vagility
• phoretic / phoresy
• inquilinism / inquiline
• corticolous
• detrital

Currently I'm working on a manuscript to coin a new eco-term. I'll keep you posted!













Thanks to Biodude for feedback on this post. I look forward to your comments.

Why Biodiversity?

Living systems are repleat with variation at every scale and level of organization.  We are interested in how such diversity is maintained (coexistence), and what the consequences of varying levels of diversity are for system dynamics (process rates, functioning, stability).  

How many species are needed for a system to persist for multiple generations? 

How many species can survive without going extinct in areas with limited resources? (coexistence)

How does the number of species affect ecosystem processes such as productivity, stability, or other measures of functioning?

How do ecosystems respond to environmental changes or other external forces such as pollution, fragmentation, or climate change? (stability, resistance, resilience)

How do evolutionary processes affect ecological patterns and processes and vice-versa?

Gazing at Gaia's Navel

On a more philosophical note, studying biodiversity sometimes feels like "navel-gazing", while you are studying minute details of an immense biosphere, of which we are a part.  But, it's like looking at Gaia's navel, which so much more interesting than your own.

A diversity of reasons

Although our lab shares some common approaches to studying biodiversity, we each have our own personal reasons for choosing to work in this field.  We invite you to post your personal reasons in the comments section of this post.

What is biodiversity science?

It is the discovery of the patterns and processes that describe and explain the diversity, distribution and dynamics of life in the biosphere. 

This is a formidable scientific enterprise because there are many more organisms on Earth than there are stars in the Milky Way! 

(Apparently there are ~100 billion stars in our galaxy) 

All those organisms are split up into many different species each of which is represented by a few hundred populations.

(Our best guess is 10-15 million different species, each with ~200 populations on average)

What motivates much of the science in our lab is the alarming rate at which populations and species are disappearing. 

Biodiversity scientists are being challenged to understand the inner workings of the biosphere whilst human society subjects it to new combinations, rates and levels of environmental change.