Comment on FR Doc # E8-29673

This is a comment on the portion of the Proposed Rule dealing with the emperor penguin, and the decision not to list it as a threatened species. We wish to draw the attention of the Service to a paper of ours, recently published (10 February 2009) in the Proceedings of the National Academy of Sciences, on the effects of future climate change on the emperor penguin. Our approach in this study (similar to that used in analysis of polar bear populations in the studies leading to the listing of that species) combines demographic models of population growth, observed effects of sea ice changes, and forecasts of future sea ice conditions based on IPCC climate models. The study is based on long-term data on the colony of emperor penguins in Terre Adelie; this colony is discussed in several places in the Proposed Rule, but the results of our study were not available during the formulation of the Rule. Demographic observations in Terre Adelie show that temporary reductions in sea ice extent lead to reduced survival and population decline. We developed a stochastic model that projects population growth under such fluctuations, and used IPCC models to forecast the frequency of fluctuations through the end of this century. We found that a suite of 10 IPCC models, chosen for their ability to describe recent Antarctic sea ice conditions, agree in forecasting an increased frequency of sea ice fluctuations. The population result is a dramatic decline in size of the population, from a current size of approximately 3000 breeding pairs to a median projected size of approximately 400 pairs. The probability of passing a quasi-extinction threshold of 95% decline is between 0.4 and 0.8. Simulations that had not reached these levels by 2100 were declining at the time. Our analysis is specific to the Terre Adelie colony. Generalization to the emperor penguin population as a whole will require additional study of future sea ice scenarios and the ecology of other penguin colonies. For a discussion of such generalizations, see a recent report to the World Wildlife Fund (http://assets.panda.org/downloads/wwf_climate_penguins_final.pdf). In summarizing knowledge of emperor penguins, their habitat, and likely future changes in that habitat, the text of the Proposed Rule emphasizes uncertainties and limits to information. We would like to point out that our study differs in three ways from all the studies cited in the Proposed Rule: 1. Our study is not based on correlations of environmental factors (sea ice, in particular) with counts of adults or chicks. Rather, it is based on the effect of environmental factors on the vital rates, that is, on rates of survival, breeding, etc. Much of modern population biology focuses on such vital rate effects as the key to projecting population growth. 2. Our study is not based on forecasts of trends in sea ice extent, but on forecasts of fluctuations in sea ice extent. In several places, the Proposed Rule notes the likelihood of fluctuations, and dismisses the importance of climate change because the future trends are not smooth. Our study shows that the frequency of the fluctuations is critically important, and is predicted to increase by all IPCC climate models. 3. Our study is not based on continent-wide forecasts of sea ice conditions, but on forecasts extracted for the specific area of the Terre Adelie colony. We suggest that the Service take these results into account in its decision on the emperor penguin. Reference (this paper is attached to this comment): Jenouvrier, S., H. Caswell, C. Barbraud, M. Holland, J. Stroeve, and H. Weimerskirch. 2009. Demographic models and IPCC climate projections predict the decline of an emperor penguin population. Proceedings of the National Academy of Sciences 106:1844-1847. Hal Caswell Senior Scientist Stephanie Jenouvrier Postdoctoral Fellow Woods Hole Oceanographic Institution