Hi! So I’ll pick up where I last left off… Despite my difficulties in writing my thesis, I am really excited about the results that we got, and I am looking forward to making our findings available to others who want to build on the work we started. Interestingly, we didn’t get results exactly in line with what we expected. Actually, that isn’t all that surprising, since it happens a lot in ecology. When scientists do hypothesis-driven research, we offer up our ‘best guess’ at the patterns we expect to see (these guesses are based on what we know from previous research, patterns in similar systems, etc.). But nature is complex and mysterious, and infinitely capable of pulling surprises. If you ask me, that is the most exciting part of ecology: the unpredictability of discovery, always – at least for me – cloaked in wonder.
To start, we found that when flamingos are removed from the lake (remember the fences we built to keep out flamingos?), big changes happen. No big surprise there. Algae grew/flourished when flamingos were fenced out, and after 1½ years of excluding flamingos, the amount of algae inside our fenced areas was over 5 times higher than the amount outside. The interesting part is that the effect of excluding flamingos depended on the amount of time that had passed. There seemed to be times when flamingo exclusion had a small effect on the amount of algae, and other times when it had a big effect. It’s possible that patterns in the seasons accounted for this: for example, the winter months could have caused a decrease in the growth of algae (because of lower temperatures, less sunlight, etc.) whereas the warmer summer temperatures may have increased growth. We’ll need to look into this further to find possible reasons why. But that will have to wait for another field season.
Another interesting result has to do with the changes in the diversity of the algae species in the fenced in areas. Before starting my fences experiment, I had predicted that algal diversity would increase in the fenced in areas that were flamingo-free. I thought that the diversity of algal species was held in check by flamingos (because of competition) and that areas without flamingos would have more algal diversity. At first, we saw exactly this. But after only 36 days, diversity began to drop in the flamingo-excluded areas and towards the end, these areas had, on average, 5 fewer species than the open areas. That’s a big difference! And in the opposite direction of what I expected! This means that losing flamingos in the lake also means losing other species like algae and possibly other species higher up the food chain (such as invertebrates and even other birds, etc.)… not a good situation.
So, I’m in the process of writing a chapter for my thesis that discusses these results. I am trying to make the case that flamingos should be considered ‘keystone species’ in their aquatic habitats. This means that, relative to their abundance, flamingos exert a disproportionately large impact on community and ecosystem structure. (You may be familiar with other keystone species, such as sea otters, beavers, and elephants). If we can make the case that flamingos are keystone species , we may be able to protect a number of other species and processes as well that depend on the flamingo. Being able to demonstrate the role of flamingos in this way (quantitatively) is important for making a case for their conservation. We’re on our way…!