Ecogeographic Surveys

One of the simplest forms of ecogeographic data analysis is to calculate the number of specimens collected from geographically or ecologically distinct sites (e.g. climate, soil types, aspect, shading characteristics, habitat etc.). This can easily be done with database or spreadsheet software. The results can be expressed on tables, bar charts, pie-charts, graphs etc. Data arranged in this fashion can help identify the particular niche that the target taxon prefers.

Correlation of the abundance of a taxon with ranges of particular environmental descriptors (e.g. altitude, latitude and soil pH) can be used predictively. Correlation of morphological characters with ranges of particular environmental descriptors can help indicate possible ecotypic adaptation, both in wild and cultivated material.

Pie-charts can be used to display the relative frequency of a character in different places. They are commonly used to show allelic frequencies in populations at different geographical locations, but have also been used to display morphological variation, e.g., stigma colour in Crocus scepusiensis (Rafinski, 1979). New (1958) used pie-charts to demonstrate seed coat variation in Spergula arvensis, the relative size of the circles indicated the size of the population sampled; different sized circles could also be used to indicate the number of database records from which the frequency has been estimated. Pie-charts can also be used to compare the distribution of specimens with physical characteristics, e.g., altitude, temperature or soil type. Daday (quoted by Jones, 1973) used pie-charts to show the relationship between the distribution of cyanogenic forms of Lotus corniculatus in Europe and January isotherms.