Gage, S. H., S. A. Isard, and M. Colunga-Garcia. 1999. Ecological scaling of aerobiological dispersal processes. Agricultural and Forest Meterorology 97:249-261.

A variety of organisms change their geographic locations during their life history, and many use the atmosphere to accomplish this shift. Biota that flow in the atmosphere range from very small (viruses, bacteria, pollen, and spores) to quite large (weed seeds, aphids, butterflies and moths, songbirds, and waterfowl). As these organisms move, they experience meteorological and ecological conditions that occur at a wide range of spatial and temporal scales. We present an ecological scaling approach that integrates concepts and elements of spatial and temporal scaling to understanding aerobiology and provide examples of the ecological scales important to the long-distance aerial movement of organisms and associated biological events and processes.

An operational framework for ecological scaling of long distance biota movement is achieved by linking spatially-static ecoregion classification systems with temporally-dynamic measures of vegetation phenology. The ecoregions provide ecological boundaries for the phenological dynamics of plants. Operationally, this approach integrates the bi-weekly vegetation greening indices (NDVI) derived from AVHRR or TM satellite data (representing temporal scaling) with the less dynamic land cover–land use classification (IGBP) and the relatively static ecoregion boundaries (representing the spatial scaling). We argue that the correlation of the life histories of species, especially the timing of take-off, to ecosystem phenology through meteorological-based variables and indices (e.g., degree days and moisture indices), allows for dynamic characterization of source ecosystems and can be used to parameterize atmospheric models to forecast the flow of biota in the air.

The scale of these processes, the diversity of the types of biota involved in long-distance movement, and the complexity of the processes require systems thinking. We anticipate that this paper will stimulate studies to enhance our understanding of the flow of organisms in the biosphere.

Associated Treatment Areas:

Regional or Synthesis

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