Human Behavior Needs To Change To Preserve Biodiversity
15 Jan, 2007 11:13 am
Dr. Michel Loreau is professor of theoretical ecology at McGill University. He was the recipient of the Silver Medal of the National Centre for Scientific Research in France in 2004. Dr. Loreau introduces us to some elements of biodiversity, calling for awareness and a change in human behavior to preserve biodiversity.
There are indeed a number of cause for biodiversity changes and actually the first one is that loss of habitat and apparently invasive species are one of the other major causes of ? biodiversity, itís mostly on islands that it can be recorded and the reason for that is that island systems have been isolated for a long time from other sources of species coming from other regions of continents and local faunas and floras are adapted to the other species that live at those places and sometimes they are predators or disease or competitors that are completely different that come from other regions or continents and thatís why then invasive species can become major problem with devastating consequences. In most cases invasive species actually have a relatively small consequence, but from time to time even on continents they create major damages and so we still have a lot of difficulties predicting which species will have dramatic consequence and which wonít because there are many species actually that get adapted locally and that donít create such big problems so invasive species are one of the big causes of biodiversity loss but itís quite heterogeneous. Another one is climate change but this is still debated of course but the climate is changing but the debate is whether the current climate change is due to human activity and to what extent the predictions our climate models will hold in the future and if they are true, they predict important climate change in the future and this might affect a lot of species and some projections even talk about 15 to 1 third of all existing species will be threatened by just climate change so clearly there are different potential causes but actually the main cause currently is actually habitat loss because of human activity that is we as humans try to use knew habitats, we destroy existing habitats, which means a lot of species are currently disappearing because of that, thatís the major one today.
Do we have a clear idea of the impact of climate variability on biodiversity? What can we learn from species-climate modeling?
What we do know is that climate affects the distribution of virtually all species to variable extents, what we observe currently is the shifts in the distribution of species, thatís already going on now, although climate is changing only gradually and only in the recent years have we seen big changes in climate but it might be very temporary we donít know that but thereís a longer term gradual change which is not so big but it does already have big impacts on the distribution of species. If you change by only half of a degree the temperature that will perhaps change by several hundred kilometers the distribution of species that are able to migrate at a fast rate and for instance some insects and some birds and some plants as well and so what we observe now especially towards the poles because thatís where the temperature is changing most, we see a gradual shift of the distribution range of species towards the north. Itís mostly documented for the northern hemisphere actually because we have more studies there, so thatís one thing that we already know now and another thing we observed is the shift in phenology. Phenology is the description of how species are active in the season, plants start growing at a certain date and they stop growing at a certain date then we clearly see a shift in these dates that is the growing season become longer means that plants and insects become active earlier and sometimes later in the season so the growing season becomes longer. These things are already known now but in the future it might be much more dramatic, these changes in distribution range and also phenology. Could be much more important with potentially big changes in existing communities, it also shifts the competitive abilities of the various species, some species become better competitors than others, so it might have a lot of indirect effects as well, we have difficulties predicting accurately.
In regards to wildfires, there has been an increase in their frequency, severity, and extent of wildfires in recent years. How do they affect biodiversity loss?
I donít know of studies showing that increased fires will change biodiversity at a global scale but it certainly has a big affect locally, it goes in two ways because destroys a lot of bio mass and individuals, but at the same time a lot of species are actually dependant on fires to survive, we know for instance that a number of plant species actually actively promote fire because itís there means of surviving against other competitors that are less fire resistant so it means that fire increase in frequency and extent, perhaps the net extent will be biodiversity loss but it also means that some species will have competitive advantage over other species and probably it will mean a change in community composition. But I donít know of large scale studies showing that fires are changing biodiversity at a global scale.
How important is natural variability in biodiversity loss?
Natural variability is extremely important to biodiversityóit has always been there. To some extent, some species are dependent on this natural variability. It is essential to it, in fact, a part of biodiversity. It is a natural occurrence that happens constantly; it is natureís way of keeping things in check. But the idea that of a nature with everything in balance, in harmony, isnít real. It doesnít exist, because really nature is changing all the time and many of these animal species are adapted to these changes. Those that arenít adapted change habitat, migrate, or are adapted in other ways. Variability can be characterized by some statistical properties, with averages, the variants, and things like that. Variability can change in a big way as well as in a small way; it can greatly affect things locally or not. This will change the species that are adapted to local conditions. Even in places that we feel are constant, like a tropical rainforest, we know very well that they have been changing for thousands of years. We have to realize that. Itís not that humans are changing the environment in itself. Humans are changing in a consistent direction at a very fast rate. A lot of these species cannot change at this rate.
There is a call for a common agenda to preserve biodiversity by groups like DIVERSITAS. Can you outline some possible steps we need to take to preserve biodiversity?
DIVERSITAS is an international organization that promotes biodiversity science in general, all aspects. It would like to provide means to better preserve biodiversity, but this is also part of the agenda. We have measures to preserve biodiversity, but they are obviously not working well. We have measures in place locally, with some success stories. At the global scale, itís not enough. First, weíd like to assess what is working and why, also what is not working and why. There are many alternatives to better preserve biodiversity, but we donít have a rigorous objective. We know that ultimately, these causes are anthropogenicóthey are caused by humans. It is human behavior that is the final determinant with what weíre going to do about biodiversity; itís not natural variability as we discussed earlier. We spent the final step of our paper to study why people work to preserve biodiversity or lose it. Currently the motivations to lose it are much stronger than the motivations to preserve it. We believe that if we have a better understanding of the role of biodiversity in the long run, weíll be able to progressively change the policy rules and maybe the behaviors of humans themselves. Most people live now in cities and donít realize they depend on biodiversity. Itís possible to raise the awareness of people in the long run. We have a lot of research on that to do in the long run. We try to address these issues, because they are not only natural causes. Iím afraid I canít be optimistic in short run. I think it will be difficult to change the behavior of people; people like to think they are outside of nature but they are not. Personally, I believe it will take some time. Itís like climate change: people need to see the effects of it to really change their behavior significantly.
Interview by: Thanh-Tam Candice Vu