Carefully placing the reflectometer on a black rhino's nose in the Brookfield Zoo, professor Warren Porter documented the rhino's ability to reflect sunlight.
While the rhino passively ate bread from the zookeeper, Porter read the reflectometer, a device measuring reflected light, and found the rhino reflected only 12 percent of the sun's rays.
Apart from the privilege of being in the presence of an endangered species, Porter, a zoology professor at UW-Madison, relished the opportunity to collect every detail of local animals, such as the black rhino. From this research, Porter will use computer algorithms and equations to predict future effects on animals, such as the effects of climate change on the black rhino.
So, how does Porter's crystal ball work?
Sufficient data is necessary for the computer model, a simulation that will predict results based on input parameters, to foresee how climate change will affect an animal. For instance, to determine how the population will react to the change, there needs to be considerable data about the individual animal. This model needs to include the animal's genetics, behavior (both temperature- and sex-dependent), physiology and morphology, or body shape.
These are key to the model, because from this data scientists can build another model or equation to find how much an animal needs to eat and how much energy it spends. These two factors will tell scientists how the climate change will affect the black rhino's ability to survive and grow.
For example, the black rhino is black because of its genetics, and its typical behavior is to stand under a shrub to keep cool. The rhino's shape is a large oval, which means its body can easily retain heat from the sun's radiation. Turning these descriptions into measurements, Porter can input the data into the computer model to find how much energy the rhino needs to expend on daily activities, such as maintenance of core body temperature, growth and reproduction.
This model will then describe how well the rhino can survive, grow and reproduce given the environmental surroundings.
Once we know the properties of the rhino, we then can calculate the metabolic rate in different amounts of shade,"" Porter said.
Porter organized the computer calculations into different graphs. One graph demonstrated the rhino's metabolism, which showed little variation over 12 months in differing amounts of shade. There was little variation because overall, ""in the hot months (October-March) metabolic rates are lower than in the cool months (June-August) when metabolic rates have to be higher to maintain body temperature.""
However, on another graph, the different amounts of shade had significant effects on water evaporation rate because ""in all weather, water loss requirements are significantly lower once shade values begin to exceed 40 percent.""
""These rhinos definitely have to have shade, especially in [the] hottest and driest parts of the year,"" Porter said.
The radiation affects the rhinos because they have a thick boundary layer between the skin and the ""free stream"" air. ""Since they have that layer, they are not easily cooled by the air, and they can become really sensitive to the radiation load, like cattle,"" Porter said. ""So vegetation is really important to them.""
This is why Porter found the majority of the rhinos in the northern part of the Serengeti in Kenya, where there are many trees during the hottest part of the season. During the rainy season, the rhinos move back down to the lush vegetative fields in the southern portion of the Serengeti. These observations show how landscape and climate affects the movement of rhinos.
The computer models are great estimates for scientists to see how global warming will affect animals. And they offer solutions, too, such as planting more shrubs in the Serengeti.
But how reliable are these computer models?
""We are constantly testing them,"" said Porter. ""The most recent test was down in Kalgoorlie, Australia, where Dr. Michael Kearney from the University of Melbourne was doing some work. We had temperature loggers placed at the surface, 2.5, 10, 20 and 50 cm below the surface.""
Porter showed a graph with temperature loggers, a small thermometer-like instrument, at different depths in the soil for recording the air and surface temperature. He then ran a computer model based on the soil composition of the area that would predict the air and surface temperature. The results of the computer simulation varied by only a few tenths of a degree from the temperature logger's data. This means that the computer models have been accurately applying the correct temperature for the animal's height above or below the ground in the simulation.
So far, Porter's models have accurately predicted how certain animals will react to climate changes. However, the previous models were all done for land creatures. What about sea creatures?
Marine animal modeling is the subject of his future research. New 3-D software will scan an animal such as a sea turtle and show the fluid dynamics of the sea turtle as it glides through the water. Knowing this, as well as the animal's metabolism, Porter will be able to figure out how much energy the sea turtle will need to expend to keep its core body temperature regulated as the temperature of the ocean fluctuates.
These computer models will help show how some of the future effects from climate change will influence animals' survival. Whether on land or in the ocean, the animal constantly adapts to the environment. Yet, it's important to remember the animal is not an equation, represented perfectly by balanced numbers. For an animal, there is a real-life breaking point - the point that determines if it lives or dies.
""Climate variability is important,"" Porter said, in determining ""how animals survive.
