Methods to detect species range size change from biological atlas data: A comparison using the South African Frog Atlas Project

作者：Botts Emily A^*; Erasmus Barend F N; Alexander Graham J

来源：Biological Conservation, 2012, 146(1): 72-80.

DOI：10.1016/j.biocon.2011.10.035

• Biological atlas
• Species distributions
• Range contractions
• Range expansions
• South Africa
• Amphibians

Comparing historical species distribution data with recent biological surveys has the potential to quantify changes to species geographic ranges, and to detect declining species. The primary concern in making species range size comparisons between dissimilar datasets is the problem of incomparable sampling intensities. For South African amphibian data, an increase in sampling intensity over time was associated with a move from ad hoc to more coordinated sampling. The consequent increased geographic coverage and higher detection probabilities resulted in false range expansions. We assessed several approaches for managing variable sampling intensity: categorical comparisons, sub-sampling and correction factors. These methods were first applied to hypothetical ranges for evaluation, and then to the observed data of the South African Frog Atlas Project. Categorical comparisons oversimplified quantitative data and correctly measured the sign of change for fewer than 56% of the hypothetical ranges. Sub-sampling methods correctly estimated the sign of change for up to 78% of the hypothetical ranges, but it is essential to balance data removal with a reduction of false range expansions. The best measure of hypothetical range change was a mathematical correction factor, which achieved 83% accuracy in detecting the correct sign of change and 50% for the magnitude of change. According to this method, 68 (60.2%) South African frog species are likely to have undergone range contractions. The careful use of methods such as those assessed here allows for ad hoc data collections and biological surveys to be valuable in quantifying species range change, and hence for identifying potentially declining species.

• 出版日期2012-2