Research on biodiversity has mostly been performed in small scale controlled experiments. A new study by the Smithsonian Institute and the University of Michigan has researched the effects of biodiversity in the wild. We interviewed Emmett Duffy, the lead author of the study.
Can you tell us how the study on the effects of biodiversity on real world ecosystems was performed?
We searched for all the scientific studies we could find that measured productivity of a natural ecosystem along with the number of species present and environmental factors like temperature and rainfall. Then we used statistical methods to separate and compare the contributions of diversity and environmental factors to productivity.
Did you look at productivity only or also at other ecosystem properties?
We focused on biomass production because this is the ecosystem variable that has been most widely measured and because biomass production is central to so many other ecosystem features such as habitat structure, nutrient cycling, and so on.
What were the main conclusions from the study?
The main conclusion is that the diversity of life forms in an ecosystem is just as important as climate and nutrient inputs in determining its productivity. In fact, biodiversity is even more important in wild nature than expected from experiments, which was a big surprise.
Real world ecosystems are very complex so how did you control for other environmental factors in your research?
In the last decade or so, powerful statistical approaches have developed for cutting through the Gordian knot of complexity in wild ecosystems. As the old saying goes, correlation is not causation, meaning that it’s hard to nail down causes definitively without experiments. Still, because the patterns we found are so consistent with previous experiments and with theoretical predictions, we feel pretty confident they are real.
How does the influence of biodiversity on ecosystem productivity compare to other influences like climate and nutrient availability?
The biggest surprise of this study was that biodiversity appeared to affect productivity just as strongly as climate and nutrients, which are widely considered, master drivers of ecosystem processes. We were all blown away by this – it was really unexpected,
What do you consider to be the explanations for this strong relation between biodiversity and productivity of ecosystems?
There are several possibilities, probably all of which are acting in one situation or another. First species can help one another mutualistically, as plants do with pollinators or corals do with their symbiotic algae. These partnerships have a big influence on how ecosystems work. For example, coral reefs would not exist without that relationship. Second, diversity can provide insurance when conditions change, as they are always doing. Having many species in a system can ensure that at least some of them thrive when conditions change, just as a diversified stock portfolio protects investors from market fluctuations.
Is the effect of biodiversity immediate or do you see a growing impact when the timeline is longer?
We were not able to drill down to that level in our analysis because most of the field studies we found did not include a series of measurements through time. But controlled experiments in both land and marine plant communities indeed show that biodiversity has a stronger influence on productivity through time as the community matures.
What do the finding mean for policy makers?
These results confirm what has been suspected from experiments but never proven in nature: that loss of species can strongly reduce nature’s productivity. This could compromise fisheries, timber production, and other resources we depend on just as human population and needs are growing rapidly. In other words, biodiversity is more than just a pretty face. Having healthy, diversified biological communities is central to the productivity and stable functioning of ecosystems that humanity depends on.
Photo’s courtesy of Emmett Duffy.
There is a lot of attention on the effects of fossil fuels on climate change. But the effects of deforestation and the use of forest lands for agriculture are often overlooked. A recent study by Cornell University addresses the effects of deforestation on climate change. We interviewed the Natalie Mahowald, the lead author for the study.
To put things into perspective, can you give an estimate of the effect of deforestation on the climate?
Right now it is contributing about 40% of the warming we are experiencing. By 2100 it could force a warming of 1 degree.
Which areas have the most deforestation at the moment?
Tropical areas are at most risk for deforestation right now.
What are the main mechanisms between deforestation and climate change?
Deforestation directly releasing carbon dioxide during the deforestation. In addition much of the deforested lands are converted to agriculture or pasture usage, both of which cause emissions of green house gases like methane and nitrous oxide. These contribute to the warming from deforestation.
There is a lot of attention on CO2 as a greenhouse gas, but does deforestation also causes higher emissions of other greenhouse gasses?
Deforestation leads to agriculture and pasture usage in many cases, and both cause emissions of green house gases…
In the study you stress the importance of looking at these effects on a longer time-scale, or multi-centennial legacy of current land-use decisions. Can you explain why this is important?
Solving climate change is a really really difficult problem which will require at a minimum a conversion of our energy sector to sustainable energy extremely fast: potentially faster than can be technically done, but perhaps also faster than is politically feasible. Deforestation, as we show here, and the conversion to agriculture and pasture usage also contributes to climate change. In addition, to avoid the worst of climate change, we also need to remove carbon dioxide from the atmosphere, which we don’t have good technologies for, unless they use a lot of land, which has many environmental impacts, as well as causing climate change themselves. Thus it is likely that we will be dealing with the impact of climate change for a long time: thus understanding the long term implications of land use, which not only causes emissions of CO2 during conversion, as well as the emission during agriculture and pasture usage, but also causes the removal of a long term natural sink of carbon in the forests.
What are the possible measures available to revert the process of deforestation?
Deforestation is a difficult process to control, but understanding that stopping deforestation not only protects biodiversity but climate could bring more resources to bear on the problem. Deforestation can be driven by large businesses but often is driven by individual poor citizens looking for a way to feed themselves. So providing incentives for locals to protect the forests, as well give them a livelihood has been successful approach for protecting forests.
Is it also possible to change our agriculture in a way so that the soil functions more as a carbon sink and emits fewer greenhouse gasses?
Yes, there are ways to make agriculture more sustainable, and these efforts need to be enhanced and incorporated. Most of these approaches also enhance soil fertility so this is a win-win situation.
About 90% of the world population breaths air with a lower quality than the World Health Organisations standards. So how is the air quality where you live?
You can find out by joining a world-wide community sensing network that uses an air quality sensor called the “Egg”. It measures the levels of Carbon Monoxide, Carbon Dioxide, Sulphur Dioxide, Fine Particles, Nitrogen Dioxide and Volatile Organic Compounds.
You can use a smartphone app or a web dashboard to monitor and share the pollution data with other participants in this global environmental science experiment. You can also use the findings to press local policy making towards improvements in air quality.
For more information about this project : https://airqualityegg.wickeddevice.com
Organic agriculture can be a major instrument to reduce the amount of CO2 in the atmosphere. We interviewed Kris Nichols of Rodale Institute about the relationship between agriculture and climate change.
Science Newsflash: Oceans and wildlife are being polluted by plastic microbeads that are used in toothpastes and shower gels. They are not biodegradable and pollute the marine environment forever. A team of researchers at the University of Bath came up with a possible solution for this problem by creating microbeads from cellulose which is biodegradable.
Invasions of non-indigenous species are thought to be important drivers of biodiversity loss in freshwater ecosystems. Carlos Gracida Juárez is doing his postgraduate research on this topic at Bristol University.