Currently, many countries are trying to introduce biodiversity offset policy and seeking overseas reference cases. The wetland mitigation policy in the United States is a pioneer of biodiversity offset policy and considered a useful reference case, yet the history of the policy has not been well evaluated. To understand what issues they have been addressing is essential to elicit lessons from the precedent, and quantitative analysis of longitudinal shifts of policy foci can provide objective assessment in that regard. In this research, I conducted content analysis of public documents about the wetland mitigation policy to quantitatively evaluate longitudinal shifts of policy foci. As a consequence, the analysis revealed that the policy is getting to focus more on effectiveness and efficiency and less on equity, which is different from the initial expectation based on literature review.
Species distribution models（ SDMs） are useful tools for habitat assessment studies in plant and animal species. However, the applicability of SDMs when considering primary environmental impacts remains to be verified. Here, I evaluated the predictiveaccuracy and ecological understandability of SDMs in a case study of the Japanese endangered salamander （Hynobius tokyoensis）. I constructed two maximum entropy （MaxEnt） models and one logistic regression model using national geographical databases. The model constructed using MaxEnt with default settings showed the highest predictive accuracy but provided inadequate ecological understandability. The remaining two models showed adequate ecological understandabilities and predictive accuracies. Hence, a key criterion when considering primary environmental impacts is the use of understandable SDMs for consensus formation.
It's necessary to avoid influence in local hot spots and understand representative value in a target area for environmental impact assessment. Hot spots can be determined by calculating the ratio of a radiation dose rate at one height to that at another height at the same location. An environmental radioactivity impact assessment method for obtaining the accurate representative value for the surveyed area, and for determining the size and the appearance ratio of hot spots was proposed based on the height-radiation dose rate relationship. In this method, the optimum number of sampling locations is determined by eliminating the number of hot spots by subtracting the number of hot spot locations from the total number of sampling locations, and by keeping the sampling number within the required statistical error.