Mapping Species and Growth Patterns

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Geographers, climatologists, and ecologists handle large databases that have accumulated years of information on weather, precipitation, biota, human populations, surface waters and flow, and soil types. Several years ago scientists collected data on all these things by hand tabulations. Today they use global positioning systems (GPS) to determine the exact position of the small areas being measured. Geographic information systems (GIS) have become even more useful than GPS. GPS tells users their exact geographic location, but GIS includes other pieces of information in large databases. GIS calculates and analyzes data so that scientists can create maps of complex things such as biodiversity, natural resources, different types of pollution, and global sea temperatures. In 2007 the Intergovernmental
Panel on Climate Change (IPCC) released a report on the latest effects of global warming from data generated from global mapping. “Warming of the climate system is unequivocal,” the report said, “as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global mean sea level.” Ocean depth, currents, and temperature maps have now been applied to concentrated studies in select parts of the world. For instance, Gilly Llewellyn of the World Wildlife Fund described to the Australian newspaper in 2006 studies being conducted on the Southern Ocean and Antarctic marine habitats: “This map will help us to better understand the Southern Ocean so that we can address the major threats to its habitat and wildlife, such as illegal fishing, climate change and the impact of invasive marine species.” Environmental science continues to blend simple manual methods of study with advanced electronic technologies.

Mapping methods target two features of individual animal species: range and incidence. Range is the widest area where a population of animals roams, and incidence is the number of times animals occur in their range. Biologists create separate range maps and incidence maps, then put one atop the other for each species. In this way the maps show the density
of a species throughout its range. These range-incidence maps can be made to cover areas as large as 250 square miles. The large-area maps consist of many maps of small areas, called grids, compiled into a single overview of a large region. For example, the range-incidence map of California contains 300 individual grids.

Richness measurements can also be mapped to give biologists a close approximation of an area’s biodiversity. Scientists in fact often refer to richness as a measurement of diversity. Rarity, by contrast, indicates any

 

This diagram depicts the steps used by the California Department of Fish and Game for
measuring and mapping biodiversity. Biologists first divide the state into 300 equal area
regions, then teams count all the species they find in each region. The biologists then
construct maps to show the range where each species is found. By overlaying all the maps,
they build a biodiversity map to indicate high, moderate, and low regions of biodiversity.

threats to biodiversity in an area. Areas with the highest rarity values are those in which all species exist at a very low incidence. Environmental organizations such as the IUCN construct maps of today’s evolving hotspots by focusing on richness, rarity, and endemism. The “Biodiversity Hotspots around the World” sidebar discusses these places of amazing
biodiversity.