NCEAS Project 2149

Paleoecology of North American mammals: Large-scale patterns and processes

  • John Alroy

ActivityDatesFurther Information
Postdoctoral Fellow1st September 1998—31st August 2001Participant List  

During my residence at NCEAS, my activities would focus on three areas:

1) Supervising the working group on Phanerozoic marine diversity. The working group's first meeting will immediately precede the beginning of my stay at NCEAS. During this meeting we will agree upon a database format, and upon narrow goals for data compilation. I expect that contributed data modules will need to be uploaded or scanned, checked, and possibly augmented. Some of this work could be carried out by an undergraduate or technician working under my supervision. I also expect to correspond frequently with working group members as the project progresses, and to be involved with planning the group's meetings. I am likely to work on designing new computer programs to carry out statistical analyses, or on adapting my own, existing programs for this purpose.

2) Completing new data modules that I have begun adding to my North American mammalian paleofaunal database. These include a lower first molar size measurement data set, which I am using to estimate body mass; an upper cheektooth measurement data set, which I will use to construct a size/diet ecomorphospace that will distinguish herbivores, carnivores, and generalized insectivores/omnivores; a species-level phylogeny, which I will use to study within- and among-lineage dynamics of evolutionary trends; and a specimen count data set, which I will use to study trends in alpha diversity. All of these data sets will be compiled from published literature using my existing photocopy and reprint collection. However, because some of the photocopies are incomplete I will need to augment them. Some of this work could be done at UCSB. Some of the more obscure references might have to be obtained by interlibrary loan, although a stay of a few weeks at a facility having a major natural history library (e.g., the Smithsonian Institution; the University of California Museum of Paleontology) might be more efficient.

3) Developing new statistical methods and completing manuscripts. I am now working on several paleoecological projects that I expect to complete at NCEAS. These include methods that objectively identify "adaptive radiations," defined as phylogenetic groups that briefly experience rates of speciation far greater than those of other, contemporary groups; an analysis of variation in speciation and extinction rates across the body size spectrum; a new method ("boxing and streaking") that describes non-linear, within-lineage trends in pairs of correlated variables; an analysis of changes through time in the underlying dynamics of within-lineage morphological evolution; the development of new, unbiased statistics to describe within-locality body mass distributions; and studies on the relationship between sampling intensity and alpha diversity at a local scale.

Most of these projects relate to global climate change trends because such features as speciation and extinction rates, alpha diversity, local body mass distributions, and the underlying dynamics of body mass and ecomorphological evolution all appear to shift in response to major environmental events. I may also continue my earlier work on diversity dynamics (e.g., by completing development of a new method for defining "evolutionary faunas"; by studying the impact of intercontinental immigrants on turnover rates; by testing non-linear diversification models), and on correcting diversity curves for sampling biases (e.g., by studying the distinctions between randomized subsampling based on faunal lists or on independently drawn taxonomic records).

TypeProducts of NCEAS Research
Presentations Alroy, John. 1998. Cenogram statistics: What do they tell us about the evolution of body mass?. Society of Vertebrate Paleontology. Snowbird, UT.
Presentations Alroy, John. 1998. Differential turnover across the mammalian body size spectrum: Diversification trends governed by equilibrial dynamics. Geological Society of America. Toronto, Ontario.
Presentations Alroy, John. 1998. Inferring evolutionary patterns and processes from a phylogeny of North American fossil mammals. Louisiana State University. Baton Rouge, LA.
Presentations Alroy, John. 1999. Can molecular data demonstrate ancient mass extinctions and adaptive radiations?. Society of Systematic Biologists. Madison, WI.
Book Chapter Alroy, John. 1999. Putting North America's end-Pleistocene megafaunal extinction in context: Large scale analysis of spatial patterns, extinction rates, and size distributions. Edited by MacPhee, Ross D. E.; Sues, Hans-Dieter. Extinctions in Near Time: Causes, Contexts, and Consequences. Plenum. New York. Pages 105-143.
Journal Article Alroy, John. 1999. The fossil record of North American mammals: Evidence for a Paleocene evolutionary radiation. Systematic Biology. Vol: 48. Pages 107-118.
Presentations Alroy, John. 1999. Was North America's end-Pleistocene megafaunal extinction caused by climate change? The numbers say no. University of California, Santa Cruz. Santa Cruz, CA.
Journal Article Alroy, John. 2000. New methods for quantifying macroevolutionary patterns and processes. Paleobiology. Vol: 26(4). Pages 707-733.
Journal Article Alroy, John. 2000. Successive approximations of diversity curves: Ten more years in the library. Geology. Vol: 28. Pages 1023-1026.
Journal Article Alroy, John. 2000. Understanding the dynamics of trends within evolving lineages. Paleobiology. Vol: 26(3). Pages 319-329.
Journal Article Alroy, John. 2001. Did human hunting cause mass extinction? Response. Science. Vol: 294(5546). Pages 1461-1462.
Book Chapter Alroy, John; Koch, P. L.; Zachos, J.C. 2001. Global climate change and North American mammalian evolution. Edited by Wing, Scott L.; Erwin, Douglas H.. Deep Time: Paleobiology's Perspective. University of Chicago Press. Chicago. Pages 259-288.