Annual report for Ottar N. Bjornstad for the period 09.15.98-11.15.99. Postdoctoral fellow on Project 2146: Recruitment Variability and Populations Dynamics.

I have produced 5 manuscripts on my main NCEAS projects relating to stochastic age-structured dynamics. Of these five, three are already published (Ecology and Proc Natl Acad Sci, Proc Roy Soc Lond B), and two have been submitted (Ecology and ICES). A sixth study developing a theoretical framework for understanding the effects of recruitment variability is currently in preparation (in collaboration with Roger Nisbet at UCSB).

I have in addition published a review on spatial ecology in TREE. In collaboration with other postdocís at the center, Iíve had a paper on theoretical aspects of population synchrony accepted for publication in Am. Nat. I just submitted a related theoretical study to Proc Roy Soc Lond B). I have further submitted two other manuscripts for publication in more methodological journals (Ecol Environ Statist and J Amer Statist Assoc). Three papers from my previous postdoc have further appeared (2xEcology, Oikos).

A travelling grant from the Norwegian Science Foundation allowed me to take an unpaid leave from NCEAS to spend two month (Sept-Oct 99) at the Dept of Zool in Cambridge, UK, to work on the dynamics of Childhood diseases.

I have partaken in two NCEAS working groups: Leibhold & Gurevtichís Spatial Analysis, and Dobson & Holtís Conservation and Disease. Both of which are ongoing events. As part of my main project I spent 5 days at UW in Seattle with Ray Hilborn discussing various statistical issues. In connection with the disease working group I spent 10 days in Princeton (visiting Andy Dobson), and a week at the CDC in Atlanta (visiting Jamie Childs).

I have given invited lectures (and thereby represented NCEAS) at the following institutions:
Department of Ecology and Evolutionary Biology. University of Princeton.
Department of Ecology, Evolution and Marine Biology. UCSB.
Department of Statistics, UCSB.
School of Fisheries, University of Washington.
Centre for Disease Control and Prevention, Atlanta, Georgia.
Norwegian Academy of Science an letters, Oslo, Norway.
Kings College, Cambridge, UK.
Dept Math-Stat/Dept Biology, Warwick, UK.

I have contributed locally by organizing the NCEAS open house. I am also involved in other collaborative work with visitors and residents at NCEAS and UCSB.

Details on the Publications:
1. Kendall, B. E., Bjørnstad, O. N., Bascompte, J., Keith, T. and Fagan, W. (2000) Ecological interactions, environmental correlation and spatial synchrony. American Naturalist, in press.
2. Bjørnstad, O. N., Ims, R. A. and Lambin, X. (1999) Spatial population dynamics: Causes and consequences of spatial synchrony in density fluctuations. Trends in Ecology and Evolution 14:427-431.
3. Bjørnstad, O.N., Fromentin, J.-M., Stenseth, N.C. and Gjøsæter, J. (1999) A new test for density-dependent survival: the case of coastal cod populations Ecology 80:1278-1288.
4. Bjørnstad, O. N., Fromentin, J.-M., Stenseth, N. C. and Gjøsæter, J. (1999) Cycles and trends in cod population. Proceedings of the National Academy of Science USA 96:5066-5071.
5. Bjørnstad, O.N., Stenseth, N. C. and Saitoh,T. (1999) Synchrony and scaling in dynamics of voles and mice in northern Japan. Ecology 80:622-637.
6. Saitoh, T., Bjørnstad, O.N. and Stenseth, N. C. (1999) Density-dependence in voles and mice: a comparative analysis. Ecology 80:638-650.
7. Stenseth, N.C., Bjørnstad, O.N., Falck, W., Fromentin, J.-M., Gjøsæter, J., and Gray, J.S. (1999) Dynamics of coastal cod populations: intra- and inter-cohort density-dependence and stochastic processes. Proceedings of Royal Society London, B. 266:1645-1654.
8. Micheli, F., Cottingham, K. L., Bascompte, J., Bjørnstad, O. N., Eckert, G. L., Fischer, J. M., Keitt, T. H., Kendall, B. E., Klug, J. L. and Rusak, J. A. (1999) The dual nature of community variability. Oikos 85:161-169

1. Bjørnstad, O. N. and Falck, W. Nonparametric spatial covariance functions: estimation and testing. Environmental and Ecological Statistics.
2. Bjørnstad, O.N. and Bolker, B. Canonical functions for dispersal-induced spatial covariance and synchrony. Proceedings of Royal Society London, B.
3. Finkenstädt, B., Bjørnstad, O.N. & Grenfell, B.T. A stochastic model for extinction and recurrence of epidemics: estimation and inference for measles outbreaks. Journal of the American Statistical Association.
4. Fromentin, J.-M., Myers, R. A., Bjørnstad, O. N., Stenseth, N. C., Gjøsæter, J. & Christie, H. Population regulation in cod along the Norwegian Skagerrak coast. Ecology.
5. Frometin, J.-M., Gjøsæter, J., Bjørnstad, O.N. and Stenseth, N.C. Biological processes and environmental factors regulating the temporal dynamics of the Norwegian Skagerrak cod since 1919. ICES.