Spatial Joint Species Distribution Modeling using Dirichlet Processes

Species distribution models usually attempt to explain presence-absence or abundance of a species at a site in terms of the environmental features (socalled abiotic features) present at the site. Historically, such models have considered species individually. However, it is well-established that species interact to influence presence-absence and abundance (envisioned as biotic factors). As a result, there has been substantial recent interest in joint species distribution models with various types of response, e.g., presence-absence, continuous and ordinal data. Such models incorporate dependence between species response as a surrogate for interaction. The challenge we focus on here is how to address such modeling in the context of a large number of species (e.g., order 102) across sites numbering in the order of 102 or 103 when, in practice, only a few species are found at any observed site. Again, there is some recent literature to address this; we adopt a dimension reduction approach. The novel wrinkle we add here is spatial dependence. That is, we have a collection of sites over a relatively small spatial region so it is anticipated that species distribution at a given site would be similar to that at a nearby site. Specifically, we handle dimension reduction through Dirichlet processes joined with spatial dependence through Gaussian processes. We use both simulated data and a plant communities dataset for the Cape Floristic Region (CFR) of South Africa to demonstrate our approach. The latter consists of presence-absence measurements for 639 tree species on 662 locations. Through both data examples we are able to demonstrate improved predictive performance using the foregoing specification

On Long-Run Monetary Neutrality in Japan

This paper comprehensively investigates long-run monetary neutrality in Japan, with due consideration to the order of integration of the money stock and real output, mainly using long-term time-series data retroactively available from the Meiji Period (1868-1912). The empirical results indicate little evidence against the long-run neutrality of money (especially defined as M2) with respect to real GNP. In addition, such findings are robust to a wide range of identifying assumptions.

The Decline in the Exchange Rate Pass-Through: Evidence from Japanese Import Prices

In this paper, we empirically examine the movement of the exchange rate pass-through to the aggregate import prices in Japan from the 1980s through 2001. We demonstrate that the exchange rate pass- through to Japan's import prices fell in the 1990s, and such a decline occurred mainly during the period from the late 1980s to the mid-1990s. In addition, we show that the decline came mainly from declines in the exchange rate pass-through in each product, rather than a shift of import share from raw materials to manufactured goods with a lower exchange rate pass-through. Moreover, the period of the decline in the exchange rate pass-through coincides with the period of the sharp appreciation of the yen and resultant structural changes in the economy and international trade. Although the advance in the globalization of Japanese firms is likely to reduce the exchange rate pass-through to import prices, it should be noted that the decline in the exchange rate pass-through does not necessarily imply that exchange rate fluctuations have become less important in connection with macroeconomic fluctuations.