Aeroecology

CECB Director Thomas H. Kunz leads an initiative to develop a new discipline of ecology

Every so often in the history of science and technology, empirical discoveries, theory, and technological developments converge, making it possible to establish a new discipline. Some past examples include astrobiology, biomechanics, molecular biology, sociobiology, and more recently, bioinformatics, macroecology, and nanotechnology-disciplines that are now well established in the lexicon of modern science and technology. Aeroecology is a new discipline that embraces and integrates the domains of atmospheric science, animal behavior, ecology, evolution, earth science, geography, computer science, computational biology, and engineering. The unifying concept that underlies aeroecology as an emerging discipline is its focus on the planetary boundary layer, or aerosphere, and the myriad of organisms that, in large part, depend upon this environment for their existence.

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False-color, thermal infrared image of flying Brazilian free-tailed bats (Tadarida brasiliensis). This image was recorded using an Indigo Systems Merlin mid-thermal infrared camera, at 60 fps. Image by T.H. Kunz , N.I. Hristov, and M. Betke.

The aerosphere represents one of three major components of the biosphere. From ecological and evolutionary perspectives it is one of the least understood substrata of the troposphere with respect to how organisms interact with and are influenced by this highly variable, fluid environment. While no organism spends its entire life in the aerosphere, propagules such as seeds and spores and numerous animal species spend a significant proportion of their lives in this dynamic environment. The biotic interactions and physical properties in the aerosphere provide important selective pressures that influence the size and shape of organisms, but also their behavioral, sensory, metabolic, and respiratory functions. In contrast to organisms that spend their entire lives on land or in water, organisms that use the aerosphere are almost immediately affected by changing boundary layer conditions (e.g. winds, air density, oxygen concentrations, precipitation, air temperature), sunlight, polarized light, moonlight, and geomagnetic and gravitational forces.

Moreover, organisms that use the aerosphere are influenced by an increasing number of anthropogenic factors such as skyscrapers, air pollution, aircraft, radio and television towers, lighted towns and cities, and more recently from the proliferation of communication towers and wind turbines that now dot the Earth’s landscape. Human alteration of landscapes by forest fragmentation, intensive agriculture, and urbanization and assorted industrial activities are all rapidly and irreversibly transforming the quantity and quality of available habitats that airborne organisms rely upon for navigational cues, sources of food, water, nesting and roosting habitats: conditions that in turn are influencing the structure and function of terrestrial and aquatic ecosystems and the assemblages of organisms therein. Climate change and its expected increase in global temperatures, altered circulation of air masses, and its effects on local, regional, and weather patterns have had and continue to exert profound influences on the dispersal, foraging and migratory behavior of insects, birds and bats. Ultimately, understanding ecosystem services provided by arthropods, birds, and bats that use the aerosphere will be important for maintaining biodiversity, human health, and ecosystem health of planet Earth.

Kunz and former post-doctoral research associate Nickolay I. Hristov organized a symposium entitled “Aeroecology: Probing and Modeling the Aerosphere: the Next Frontier,” and convened at the Annual Meeting of the Society for Integrative and Comparative Biology, January 5-8, 2008, in San Antonio. Eleven papers were presented in this symposium, each of which were recently published in the July 2008 issue of the journal Integrative and Comparative Biology. In addition to Kunz’s lead paper, which introduces the concept of aeroecology, two other papers from his lab (listed below), make important contributions to this emerging discipline.

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Cover image: thermal image of flying Brazilian free-tailed bats. Image by N.I. Hristov and T.H. Kunz.

Kunz T.H., S.A. Gauthreaux, Jr., N.I. Hristov, J.W. Horn, G. Jones, E.K.V. Kalko, R.P. Larkin, G.F. McCracken, S.W. Swartz, R.B. Srygley, R. Dudley, J.K. Westbrook, and M. Wikelski. 2008. Aeroecology: probing and modeling the aerosphere. Integrative and Comparative Biology 48: 1-11.

Hristov, N.I., M. Betke, and T.H. Kunz. 2008. Applications of thermal infrared imaging for research in aeroecology. Integrative and Comparative Biology 48: 50-59.

Horn, J.W., and T.H. Kunz. 2008. Analyzing NEXRAD Doppler radar images to assess nightly dispersal patterns and population Trends in Brazilian free-tailed bats (Tadarida brasiliensis). Integrative and Comparative Biology 48: 24-39.