What is Movement & Dispersal

and Why is it Important?

Allergens, pests, and other biota in the atmosphere affect our daily lives by influencing our health, our environment, and our agricultural productivity. It is widely known that these biota rely on atmospheric processes to disperse, and biota that die en route may still be important as allergens. Thus, the quality of life and the economic health of all humanity are affected by long-range movement of biota. Major gaps in our processes and the aerial transport of biota impede the resolution of problems caused by aerobiota.

To understand long-distance movement processes holistically, one must understand what happens at each end of the movement process. Dynamics of source area populations are crucial to the initiation of movement and the status of the biota during that movement. At termination, if organisms descend into suitable habitats, the dynamics of the fallout population largely determine its impact. Many of the questions of population dynamics have been successfully addressed using established research practices. However, the descent of aerobiota to the earth's surface is not well understood. Organisms may fall out in unsuitable habitats, then may or may not move again. Finally, the time of transport and atmospheric conditions during transport may affect the organism's mortality, viability, fecundity, and fallout location. These can all play crucial roles in determining the impact of the translated population, be it an impact on health, the environment, or agricultural/forest production. The problems caused by long-distance movement have long been recognized, and the major impediment to resolving them is an understanding of the long-range movement process itself. Study in this area will not only advance our understanding and appreciation of the science of aerobiology but will pave the way for the resolution of a broad range of practical problems.

For any organism involved in long-range movement, an important question is how that movement is maintained from generation to generation, whether it is strictly environmentally mediated or maintained through selection. The broader issue of gene flow in populations is heavily affected by long-distance movement. An increased understanding of these areas will shed much light on issues such as forecasting the atmospheric pathways and understanding the impact of immigrants. Many questions of aerial movement that relate to takeoff, horizontal displacement, and descent have yet to be answered, both in terms of the biology of the organisms involved and the large- and small-scale atmospheric processes that affect them. The aerobiology surrounding sever weather events is poorly understood. Recent advances in technology in both atmospheric and biological sciences, ... can now enable us to address these perplexing aerobiology questions.

pp. 8-9 Alliance for Aerobiology Research Workshop Report, May, 1993, Scott A. Isard, ed.