Acta Zoologica Cracoviensia, 44(2) 2001

Issue:

VOL 44(2) 2001

Keywords:

Faunistics, atlas projects, amphibians, reptiles

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Dealing with uneven recording effort in regional atlas projects on the distribution of amphibians and reptiles

• Piotr ZIELIŃSKI

Abstract:

Regional atlas studies on the distribution of animals or plants are carried out on the basis of the presence or absence of a species in grid squares, and usually volunteer recorders supply the greatest number of data. As a result, in most atlas schemes the squares differ greatly with respect to the degree of survey effort, making calculations of a species’ frequency of occurrence in space difficult. Here the author proposes a method of summarising results of regional atlas projects using the number of species recorded in each square as a measure of the recorder effort. This makes possible the calculation of an index of a species’ frequency of occurrence in space (reflecting how common is the species) on the basis of the number of squares and the number of species found in squares studied. The above procedure is illustrated using data on the distribution of amphibians and reptiles in central Poland.