Research almost never progresses in a straight line, and this is particularly true of field research. When biologists encounter unexpected obstacles, we often have to improvise new data collection methods or modify our experiments to fit the current situation. I’ve already run into some surprises this year, and it’s been a challenge to figure out solutions.

James Liu inspects arena enclosures at Fairchild Tropical Gardens.

Some of the difficulties are logistical. For example, in one of my experiments, Anolis cristatellus and A. sagrei males will compete for territory in large outdoor “arena” enclosures. The arena experiment will help me determine whether one anole species is competitively dominant over the other. Building the arena enclosures took some time, and when we finally finished them, I quickly realized that the cages were overheating because they were getting too much sun. Yesterday we moved the arena cages to Fairchild Tropical Gardens, a local botanical garden, and with luck the thicker canopy cover at the new site will keep the cages cooler.

Other challenges are biological – sometimes the organisms just don’t cooperate! When I did my preliminary fieldwork for this project last July, A. cristatellus (the Puerto Rican crested anole), was abundant throughout the sites I visited. This year, the situation is quite different – the distribution of A. cristatellus seems to be much more patchy. In some areas, I can find cristatellus relatively easily, while in other areas of seemingly ideal habitat (including areas where cristatellus was thriving last summer), I can scarcely find a single individual. Overall, the population density of cristatellus appears to be substantially lower than it was last year.

A dead Green Iguana (Iguana iguana) along Red Road in South Miami

The cause of this apparent decline is not clear, but it might have something to do with the record-setting cold temperatures that Florida experienced earlier this year. For 12 days in early January, temperatures in Miami averaged 52.7 degrees Fahrenheit, with overnight low temperatures dropping to 35 degrees in the city (and as low as 26 degrees in outlying areas of Miami-Dade County!). For Florida’s exotic anole species, adapted to warmer Caribbean climates, these extreme conditions might have been too much to handle. There were news reports of Green Iguanas (Iguana iguana; an exotic species introduced from Central and South America) literally falling out of the trees during the cold snap, and my friends in South Florida told me they were seeing dead anoles as well.

Whatever the causes, the changes that I’ve observed in the abundance of A. cristatellus pose some problems for my research. I had hoped to conduct a “removal” experiment, in which I would select an area with both species (cristatellus and sagrei) present in reasonable numbers, remove all the males of one species, and observe the effects that this removal treatment had on the remaining species. Such an experiment would allow me to determine the extent to which the two species compete for space and food resources. Unfortunately, it’s proving difficult to find sites suitable for conducting the removal experiment. Ultimately, we may have to modify the experimental design so we can take better advantage of the patchy distribution of A. cristatellus in 2010.

Biologist Jason Kolbe positions a camera and fisheye lens to take canopy-cover photographs

Last week we worked with Jason Kolbe, a postdoctoral researcher from UC Berkeley and Harvard University, to brainstorm about some alternative research plans. Like me, Jason wants to understand the interactions between A. cristatellus and A. sagrei in South Florida, but Jason is focusing on habitat use and “thermal ecology” – in other words, how these cold-blooded animals use different parts of their habitat to maintain an optimal body temperature. We’ve already come up with some promising ideas, and I’ll be sure to keep my blog updated as they develop further.