Climate change, conservation and the Rupununi

Lab Note #5
Mar 25, 2014

Climate change is a reality and it's something that effects every corner of the world. That includes the tropics, where seasonal changes are not summer-winter oscillations but wet-dry oscillations.

In the Rupununi, there is one major rainy season in June-July and one minor rainy season in December-January. The minor rainy season is not very intense and probably has a timid effect on the region. However, the major rainy season is a big deal. The flooding is so extreme that the connected savannah-forest matrix becomes highly fragmented by flood zones. An afternoon stroll in the dry season would require a oxygen tank and flippers in the wet season. It's really that serious.

Climate change has changed this dynamic. What was once a clear and intense wet season is now a longer, drawn out and less intense period of heavy rain and flooding.

The effects of this are complicated and every organism is likely to be affected differently. Local movement of many animals is determined by annual wet-dry cycles.

For insects living in forest islands, we believe the wet seasons are imposing a limitation to population movement. Remove that wet season and populations that were disconnected are now brought back together. What affect does this have? Well, it depends on how long and to what extent the populations were isolated before (which is part of what we want to find out for our project). If the populations were isolated long enough, bring them back together and we might get two brand new species through a process called secondary reinforcement. If the populations were only recently isolated then the once diverse population could become homogenized. This is bad. This means we are losing genetic diversity. Genetic diversity is healthy for populations and could potentially be a starting point for new species.

But maybe we shouldn't care about specific animals loosing genetic diversity. Maybe, as long as they don't go extinct it's ok to lose genetic diversity. Well, even if this is the case if we take a look at the whole picture we see that the changing climate is having a big impact on the region. The region, which was once a hot spot of evolution, is no longer creating biological variation through its complex and dynamic landscape. If this is the case, we're not just losing diversity but we're losing a place that creates diversity.

Of course we won't know if this problem is even occurring unless we can achieve our main goal of finding out specifically how the landscape is driving evolution. Even though our project is already funded we have a stretch goal that is extremely important to achieving a successful project. If you think that biodiversity is important, please contribute whatever you can. We appreciate it!

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