Symposium summary: Palaeoecology

Abstract

news and update ISSN 1948‐6596 sample points (hooks) and hundreds of millions of observations (fish caught). By stitching together several such datasets, and after correcting for variability in the data such as geographically un‐ evenly distributed effort, Tittensor and Worm were able to detect changes in range. They found generally similar patterns across the Atlantic, In‐ dian, and Pacific oceans, showing an apparent ef‐ fect of life‐history. Fishes that grew more slowly and to larger size and spawned in aggregations, such as the bluefin tuna (Thunnus thynnus and T. orientalis), showed decreases in range size; the range of Thunnus thynnus has contracted almost entirely from the South Atlantic, and populations are fractioning in the Pacific. In contrast, fishes that grow faster to smaller maximum size, such as the albacore tuna (Thunnus alalunga) generally have shown no change or an increase in range. Whether changing ocean climate or exploitation provide a more likely explanation is currently un‐ der investigation. Thus, we find consensus in the results of Davidson et al. and Tittensor and Worm in predicting, if human activities don’t change, an ecological extinction of the marine megafauna that echoes the extinction of the terrestrial megafauna from the Americas thousands of years ago. While in many ways we are beginning to see parallels between marine and terrestrial systems, it would be heartening to see a difference in this respect. Michael N Dawson School of Natural Sciences, University of California at Merced, USA. email: mdawson@ucmerced.edu; http:// mnd.ucmerced.edu References Barnosky, A.D., Matzke, N., Tomiya, S., Wogan, G.O.U., Swartz, B., Quental, T.B., Marshall, C., McGuire, J.L., Lindsey, E.L., Maguire, K.C., Mersey, B. & Ferrer, E.A. (2011) Has the Earth’s sixth mass extinction already arrived? Nature, 471, 51–57. Tyberghein, L., Verbruggen, H., Pauly, K., Troupin, C., Mineur, F. & De Clerck, O. (2011) Bio‐ORACLE: a global environmental dataset for marine species distribution modeling. Global Ecology and Biogeog‐ raphy, doi:10.1111/j.1466‐8238.2011.00656.x Verbruggen, H., Tyberghein, L., Pauly, K., Vlaemick, C., Van Nieuwenhuyze, K., Kooistra, W., Leliaert, F. & De Clerck, O. (2009) Macroecology meets macroevolution: evolutionary niche dynamics in the seaweed Halimeda. Global Ecology and Bio‐ geography, 18, 393‐405. Edited by Chris Burridge symposium summary Palaeoecology A contributed session at the 5th International Biogeography Society Conference – Heraklion, Greece, 7–11 January 2011 The IBS meeting is rapidly emerging as a critical meeting for those interested in paleo‐ biogeography, and in particular for those inter‐ ested in how past and present biogeographic pat‐ terns are shaped by the intersection of past envi‐ ronmental changes with ecological and evolution‐ ary processes. Paleoecology was well represented at the Crete meeting, with 25 abstracts submitted, a packed oral session, and many cross‐cutting talks. Several general themes emerged from the talks in the paleoecology session. One running theme was species niches and their shifting manifestation over time in response to new species interactions and environmental conditions . Alycia Stigall (“Using ecological niche modeling to evaluate niche stability in deep time”) applied GARP and Maxent analyses to Late Ordo‐ vician brachiopod species to show that niche con‐ servatism decreased during and after a major in‐ vasion event (the Richmondian Invasion), suggest‐ ing that species responded to invasion pressure. Jack Williams and co‐authors (“Apparent niche shifts and no‐analogue climates in eastern North America during the Late Quaternary”) tackled the problem of reconstructing ‘truncated’ niches, i.e. species’ fundamental niches for portions of envi‐ ronmental space that do not exist at present, showing that different starting assumptions re‐ sulted in very different reconstructions of species fundamental niches, and hence very different pre‐ frontiers of biogeography 3.1, 2011 — © 2011 the authors; journal compilation © 2011 The International Biogeography Society