Monitor environmental factors at breeding sites. It is necessary to identify factors that cause changes in abundance. These factors could be abiotic (e.g., air and water pollution or climate) or biotic (e.g., native or introduced predators). Water samples will be collected at all breeding sites at least twice annually (early and late in the breeding season) and analyzed for standard constituents (e.g., alkalinity, pH, conductivity, hardness, and trace metals). Climatic data will be obtained from either local National Weather Service records or from dedicated instrumentation at selected breeding sites. Weather conditions and air and water temperature will also be recorded during population monitoring. Other abiotic factors will be measured if determined appropriate. Field personnel will look for evidence of dead or moribund toads, eggs, and tadpoles to help determine if adverse environmental factors are present. Water and sediment samples will be obtained for contaminant analysis at sites where significant mortality is observed. Progress as of December 2000: Data on various biotic and abiotic factors are collected on an ongoing basis at known breeding localities. To date, no significant environmental factors, other than the pathogenic chytrid fungus, have been identified in relation to die-offs of boreal toads. In addition, work is in progress to evaluate the role of water temperature on larval growth, development, and metamorphosis. This will allow the evaluation of potential and existing breeding sites in terms of the probability, given the deposition of eggs, that boreal toad larvae will successfully metamorphose. Larval density, water level stability, and productivity are confounding factors in this relationship that are also being modeled.
