The Importance of Biodiversity

Orange-bellied Parrot - With only a few hundred of these parrots left in the wild, how does there presence or absence effect the conservation of biodiversity.

Biodiversity is a major buzzword these days, but my guess is that many people don’t grasp all that is rolled into that single word.  There are multiple measures of biodiversity and yet there is really only one commonly understood definition, the variety of life in any given area or ecosystem.

Yet for scientists, biodiversity can be understood on many levels.  For instance, let’s imagine three forests.  Each forest has 5000 individual birds flying around.  Forest #1 has 100 species of birds, each represented by 50 individuals; Forest #2 has 100 species of birds, 99 of which are represented by 2 individuals and the 100th species represented by 4,802 individuals.  Finally Forest #3 has 1 species with 5000 individuals.

If we are talking strictly about the variety of life, as stated above, then wouldn’t Forests #1 and #2 have the same biodiversity?  If we are talking abundance, well they all have 5,000 individuals.  So what exactly is biodiversity and why is it so important to conservation?  How can we distinguish between these different forests in a more meaningful way?  Let’s dive in and get our hands dirty.

Let’s look at two major components of biodiversity, species richness and species evenness.  Species richness looks solely at the number of species in a given area.  Using our above examples, Forests #1 and #2 both have the same species richness; they each have 100 species.  However, when you look at the distribution of each species, or the species evenness, you get a very different picture.

Picture species evenness as the chance of seeing one species over another.  If you walked into Forest #1, your chances of seeing any given species are equal.  However, in Forest #2, nearly every bird you saw would be a single species and you might stumble upon a couple of the rarer species.   Of course, Forest #3 is a monotypic forest with only one species.  This means it has a very low species richness but it’s hard to talk about the evenness since there is only a single species.

The third factor that needs to be considered when talking about the conservation of biodiversity is endemism.  If a species is endemic to an area, it can only be found in that specific area and nowhere else.  However, endemism works on different scales.  For example, you can say that the Florida Scrub Jay is endemic to Florida, the Carolina Chickadee is endemic to the southeast United States, or the hummingbird family is endemic to the New World.  These unique species alter our impressions of biodiversity and have major conservation implications.

In conservation, biodiversity is a major buzzword but why do we care about it so much?  The traditional argument focuses on ecosystem services.  We must conserve biodiversity in order to prevent the loss of species which might offer the keys to scientific breakthroughs like the cure for cancer or other diseases, inspiration for new products (think what the rubber tree did to the car and other industries), and so much more.

This is a good economic argument but what about the more philosophical argument.  What about preservation for the sake of species?  Does any given species have an intrinsic value?  Are we better off simply because we know a species is living out there somewhere?  I know that I am not alone in saying yes, we as individuals and as a species, are better off.

It is a mental thing, a soul thing.  Even if I may never be able to visit the tiny Inaccessible Island in the South Atlantic to see the Inaccessible Island Flightless Rail, I feel good knowing simply that it is out there.  I like knowing that the world’s smallest flightless bird is going about its daily business on a tiny 5.5 square mile island far from anywhere. Is that bird going to give us the cure for cancer?  Highly unlikely.  Is it every going to offer some sort of opportunity to improve the world economy?  Nope.  Will it’s existence every impact anyone outside of a few crazy birders trying to see every bird in the world?  I doubt it.  Does its existence matter?  Why wouldn’t it?

So let’s look back at how endemism, combined with species richness and species evenness, impacts biodiversity and conservation.  If you ran a conservation organization and your budget allowed you to preserve just one of our three example forests, how would you pick?  You’d probably pick Forest #1 with its high species richness and great species evenness.  But what if in Forest #2, out of those 99 species with 2 individuals, several were endemic to that single patch.  How would that impact your decision?  Ok, 2 individuals isn’t going to be able to produce a viable genetic population even if you could ensure their survival and breeding, but what if all the populations increased by a couple orders of magnitude and you were looking at 5 rare endemic species each with a population around 200.  Then which forest do you choose?  Can you choose Forest #1, knowing you are condemning those few endemics in Forest #2 to probably extinction?

This illustrates a very simple example of the ongoing decisions that every conservation organization must address.  How can they make the largest impact with a limited amount of funding and resources?  How do you preserve the greatest biodiversity?  What matters more? Species richness? Species evenness? Endemism?  When there is potential for a species’s, or even an ecosystem’s, existence to hang in the balance, how do you make that decision?

I don’t envy the decisions that every organization must make, but we can help.  Make your voice heard.  Support whatever conservation efforts you believe are working on a critical issue.  Is it the conservation of Inaccessible Island, the Amazonian rainforest, or a green space in your neighborhood?  Vote with your support and help to support conservation wherever you feel passionate.

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  1. That is a beautiful photo of a very rare bird Drew!

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