It is fitting that
Alex’s paper in Ecology Letters has made its debut at a time in which climate
change finds itself on the cover of most major newspapers and a subject
commonly mentioned in the US presidential campaign. The paper, entitled “Aconceptual framework for understanding thermal constraints on ectothermactivity with implications for predicting responses to global change,” nicely
illustrates the importance of having boots on the ground to measure
variables at scales
relevant to the species in question,
or in other words, of doing natural history work in order to inform climate
change models.
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| A major step towards understating climate change |
The main objective of
the conceptual framework is to predict how changes in temperature can affect
the activity windows of ectothermic species, which likely impact the
probability of maintaining viable populations. To do this, the framework shows how the
integration of basic natural history parameters of thermal physiology and
behavior can provide significant insight into models forecasting the effects of
climate change.
It should be noted
that Alex is not re-inventing the wheel. In fact, the strength of this
framework is its simplicity and organism-centered approach, in which four components
of temperature-dependent activity (thresholds, probabilities, modes, and vigor)
are integrated to predict activity windows at the scales at which organisms
experience ambient temperature and potentially respond to it, either
behaviorally, physiologically and or evolutionary. Furthermore, most of the
variables that form the building blocks for the framework were commonly
measured two decades ago. However, they have become rare in present studies of
thermal physiology. My hope is that now that Alex has shown why we need them,
they will become popular once again.
The framework is
graphically illustrated in the figure below. Two main points to take out of
this graph are: 1) the probability of activity is not a constant across all
temperatures, and 2) once an individual is active, the probability of engaging
in a given behavior will be determined by its body temperature. These
predictions should not come as a surprise to those of us that have spent time
in the field observing the behavior of individuals. But surprisingly, the use
of a probability approach to describe the activity of individuals is not
commonly integrated in current models of climate change, and even more rarely
is it recognized that different behaviors are expected at different body temperatures.
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| Figure 2, shows how the probability of activity is a continuous variable, and how the probability and of exhibiting a given would be determine by the body temperature of the individual |
And here is where the
plot thickens. When Alex was working on his dissertation, I told him that he
should consider collecting data on behavioral activity and body temperature of
free living A. cristatellus. My
recollection is that his initial response went something like this: “That is an
interesting idea, but I am not sure that collecting focal observations is
needed now, that type of studies were done a long time ago.” As a persistent
advisor, we revisited our conversation and I was able to persuade Alex to
“watch lizards” (his words) and to collect data on their behavior and
temperature. Although his level of enthusiasm for such an “old style” project
was significantly less than his excitement toward finishing the molecular work
he was working on to address genetic differences between populations of A. cristatellus. The photo below shows how happy and excited
Alex was about conducting this work, which was not very fancy and highly
unlikely to make a splash (paraphrasing his words).
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| Alejandro extremely happy after a day of "watching lizards" |
The rest is history,
and Alex has used his observations to develop insightful ideas, which are
slowly making him change his mind with regards to the value of “watching
lizards.” This perspective is a culmination of this line of work.
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| And even happier after an anole was chosen for the cover of the issue |
