It has been a while since my last post and an especially long while since my last more sciency post! The former is because I have been on vacation visiting family in Michigan and the later is because I was so inspired by Costa Rica that I couldn’t help but post about that! Luckily, as I get back to blogging, I’m inspired to write about science by a recent article in the journal Nature.
A group of 17 scientists (two of whom I almost worked with at Arizona State University) rightly decided that it was time to review all the work that has been done to determine the relationship between biodiversity and ecosystem functions and services. Their article, entitled “Biodiversity loss and its impact on humanity” takes a look at all the research that has been done since the 1992 Earth Summit to try to figure out what does biodiversity really do for us anyway? As expected, biodiversity is more important than the sum of its parts.
What does that question actually mean? Well, basically what the authors wanted to know if having many different kinds of plants and animals (or high biodiversity) in a place (i.e. ecosystem) help make that place function better and more efficiently. In order to determine the importance of biodiversity on ecosystem function, they looked at over 600 research studies and came up with six consensus statements. In order to link biodiversity to ecosystem services (or stuff we humans need), they reviewed over 1700 papers.
To sum up the consensus statements:
- Increased biodiversity means increased capture of important resources, increased production of plants and animals (biodiversity begets biodiversity), and more efficient decomposition of those plants and animals as well as recycling of the resulting nutrients.
- More biodiversity means all of those functions are more stable through time.
- This increased efficiency acts in a nonlinear way- meaning if one species goes extinct the consequences can’t be traced back in a simple manner but rather in an intricately woven web that has multiple consequences on ecosystem function.
- Biodiversity is not created equal, as the traits of different species can determine the efficiency of ecosystem functions. Similarly, the food web position of species matters. For instance, if there are two predators in an ecosystem and one goes extinct, sometimes the second one can pick-up the other’s job and keep the herbivores population low. On the other hand, if there is only one predator and it goes extinct, herbivores can take over and munch down all the vegetation, dramatically altering the ecosystem.
SO! Biodiversity isn’t just linked to ecosystem function IT IS ecosystem function. What does that mean for us? Well, the strongest evidence linked high biodiversity with provisioning and regulating ecosystem services, or, biodiversity is clearly important when it comes to feeding us, sheltering us, and regulating our soil, water, and climate.
Twenty years after the Earth Summit, we now have clear evidence that biodiversity is not just a component of ecosystems; it makes ecosystems what they are. Biodiversity literally makes the world go ’round. But what haven’t we learned? How to stop the loss of biodiversity.
The article concludes with a “Valuation of Biodiversity” section. The authors suggest that we figure out how to put numbers on the services biodiversity provides in order to basically show people how much biodiversity is worth and how much we humans owe the natural world. Valuation also helps in conservation decision making- for instance, is the amount of carbon uptake worth the cost it takes to plant trees. But don’t forget those trees provide habitat to other creatures, thus creating even MORE ecosystem services. I understand the importance of monetarily valuing biodiversity but I’m pretty sure that when we attempt it we’ll find it is worth more than we could ever possibly imagine. What do you think?