REVIEW: AMPHIBIAN SURVEYS IN FORESTS AND WOODLANDS

Amphibian surveys provide information on the distribution, abundance and habitat requirements of species, and the environmental variables that control diversity. Such information is needed for effective conservation planning and management of forests and woodlands, including monitoring of amphibian populations in a period of apparent global decline. Amphibian surveys can be time-consuming and expensive, and many issues must be addressed to maximize the reliability of the resulting data. Sampling techniques that are effective in one region or habitat type may be less so in another, and a preliminary study comparing different techniques before undertaking a survey may be necessary. Data collected in poorly designed surveys can be unsuitable for statistical analysis, and may sometimes present a misleading picture of the distribution, abundance and habitat requirements of amphibian species. This review examines issues of survey design, assesses past amphibian surveys in forest and woodland habitats, and provides recommendations for planning an amphibian survey. Firstly, the study area and survey aims should be identifi ed, and proposed sampling techniques assessed using relevant literature or a pilot study. Ethical issues associated with proposed sampling techniques should also be considered. The number, size and arrangement of the survey units (e.g. plots, sites or transects) should be sufficient to address the survey aims. The survey units should be systematically surveyed several times with appropriate sampling techniques

Extracting Additional Information From Biotic Index Samples

Macroinvertebrates were collected from a small midwestern stream over a 3-year period as part of a non-point source pollution study. Temporal and spatial variability in standard biotic index values (BIs) were computed and compared with variability expressed by a series of additional community measurements, including the mean tolerance value of all taxa present in a sample, irrespective of the numerical abundance of individual taxa. The mean tolerance value exhibited lower spatial and temporal variability than the standard BI; therefore, mean tolerance values may be useful in estimating a stream\u27s long-term ambient water quality and its recovery potential. Computations of additional BI metrics are easily accomplished with no additional lab work required, and comparisons of mean tolerance values with standard BIs should aid investigators in interpreting changes in water quality