A scatterplot is an X-Y graph of the sampled values of a pair of environmental variables from a set of species (or genus etc.) locations. Each point on the scatterplot represents the values of the pair of environmental values for a single occurrence record. You could for example plot mean annual temperature (short name called Bio01 in the Spatial Portal) against annual precipitation (Bio12) for say Eucalyptus gunnii (Cider Gum). In this case, temperature will form the X-axis and rainfall the Y axis and the points on the graph will show you what combinations each observation has. The distribution of points is usually informative.
If you want to see what subset of all our environmental layers may have some influence on the distribution of a species (or genus, family etc), then we have a tool called the Scatterplot List. This tool produces scatterplots for all combinations of multiple environmental layers for any species or group of species. For example, you could plot Eucalyptus gunnii against multiple temperature, rainfall and solar radiation variables. This makes it easy to see if there are any systematic relationships between the distribution and environmental parameters.
See Scatterplot case study for an example of how this tool can be used.