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Research Themes

Metapopulations and genetics of giant kelp

Description Personnel Products Related Data Show All
M. pyrifera gametophyte at 13 days
M. pyrifera gametophyte at 13 days

The recognition that many species live in highly fragmented landscapes led to the development of metapopulation theory, which in its simplest form represents the idea that habitat patches suitable for local populations are either occupied or not and that connectivity among patches acts to "rescue" extinct local populations. A central tenet of this theory is that the dynamics of local patches are at least partly asynchronous across the metapopulation. Our research shows that a metapopulation framework is ideal for studying the regional dynamics of the giant kelp, Macrocystis pyrifera throughout the Southern California Bight. Discrete patches of giant kelp vary asynchronously and undergo local extinctions and re-colonizations every couple of years due to physical and biological forcing that occurs across a wide range of spatial scales. Most discrete patches of kelp occur within a couple of kilometers of other discrete patches, and we have shown using empirical measurements and theoretical estimates from physical transport models and population genetics models that kilometer-scale dispersal by giant kelp occurs routinely. We recently developed highly polymorphic microsatellite markers for giant kelp to characterize its population genetics. We also developed a high resolution Regional Oceanic Modeling System (ROMS) solution for the Southern California Bight, which we are using to calculate Lagrangian particle trajectories for the purpose of estimating regional patterns of kelp spore dispersal. We are using the data derived from the application of these recently developed tools to assess genetic connectivity among local populations of giant kelp in the Southern California Bight.

The vast majority of studies on metapopulation dynamics have focused on external environmental drivers that influence rates of local extinction and re-colonization. There is growing interest in how internal mechanisms such as inbreeding depression influence metapopulation dynamics, yet there are few empirical examples that demonstrate this. Giant kelp is an ideal system for examining this mechanism because it has a high probability of inbreeding when dispersal is short and we have shown experimentally that inbreeding has significant adverse effects on the survivorship and reproduction of giant kelp. Studies are under way to examine the role of inbreeding depression in controlling the dynamics of the metapopulation of giant kelp in the Southern California Bight.

Investigators

Filipe Alberto
falberto@ualg.pt
Brian P. Gaylord
bpgaylord@ucdavis.edu
Jim C. McWilliams
Peter T. Raimondi
Daniel C. Reed
dan.reed@lifesci.ucsb.edu
David A. Siegel
davey@icess.ucsb.edu
Libe Washburn
washburn@icess.ucsb.edu
Allison C. Whitmer
whitmer@msi.ucsb.edu

Graduate Students

Laura T. Carney
2007 - 2010
Brian P. Kinlan
2002 - 2007
James R. Watson
watsonjr@eri.ucsb.edu
2007 - 2011
Mary Young
2013 - present
Gene flow inbreeding depression and population connectivity in giant kelp Canopy of a giant kelp forest
Gene flow inbreeding depression and population connectivity in giant kelp Canopy of a giant kelp forest

Publications

Alberto, F., P. T. Raimondi, D. C. Reed, J. R. Watson, D. A. Siegel, S. Mitarai, N. C. Coelho and E. A. SerrĂ£o. 2011. Isolaton by oceanographic distance explains genetic structure for Macrocystis pyrifera in the Santa Barbara Channel. Molecular Ecology, 20(12): 2543-2554. (sbc-id: 699)

Alberto, F., P. T. Raimondi, D. C. Reed, N. C. Coelho, R. Leblois, A. C. Whitmer and E. A. Serrao. 2010. Habitat continuity and geographic distance predict population genetic differentiation in giant kelp. Ecology, 91: 49-56. (sbc-id: 515)

Alberto, F., A. C. Whitmer, N. C. Coelho, M. Zippay, E. Varela-Alvarez, P. T. Raimondi, D. Reed, and E. A. Serrao. 2009. Microsatellite markers for the giant kelp Macrocystis pyrifera. Conservation Genetics 10: 1915-1917. (sbc-id: 516)

Alberto, F. 2010. Stepping stones of diversity: the Santa Barbara landscape and giant kelp genetics. ESA Fieldtalk. http://www.esa.org/fieldtalk/?p=184

Carney, L. T., A. J. Bohonak, M. S. Edwards and F. Alberto. 2013. Genetic and experimental evidence for a mixed age, mixed origin bank of kelp microscopic stages in southern California. Ecology, 94(9): 1955-1965. (sbc-id: 814)

Cavanaugh, K. C., D. A. Siegel, P. T. Raimondi and F. Alberto. 2014. Patch definition in metapopulation analysis: a graph theory approach to solve the mega-patch problem. Ecology. (sbc-id: 900)

Gaylord, B. D.C. Reed, P.T. Raimondi, and L. Washburn. 2006. Macroalgal spore dispersal in coastal environments: mechanistic insights revealed by theory and experiment. Ecological Monographs 76:481-502. (sbc-id: 317)

Mitarai, S., D. A. Siegel, J. R. Watson, C. Dong, and J. C. McWilliams. 2009. Quantifying connectivity in the coastal ocean with application to the Southern California Bight. Journal of Geophysical Research - Part C - Oceans:C10026 (10021 pp.). (sbc-id: 551)

Nelson, C. E. and C. A. Carlson. 2011. Differential response of high-elevation planktonic bacterial community structure and metabolism to experimental nutrient enrichment. PLoS ONE, 6(3): e18320. (sbc-id: 817)

Reed, D. C., B. P. Kinlan, P. Raimondi, L. Washburn, B. P. Gaylord and P. Drake. 2006. A metapopulation perspective on the patch dynamics of giant kelp in Southern California. in: Marine Metapopulations. Kritzner, J. P. and P. F. Sale, eds. Academic Press. (sbc-id: 296)

Sagarin, R. and S. D. Gaines. 2002. Geographical abundance distributions of coastal invertebrates: Using one-dimensional ranges to test biogeographic hypotheses. Journal of Biogeography, 29: 985-998. (sbc-id: 52)

Images

M. pyrifera gametophyte at 13 days

M. pyrifera gametophyte at 13 days

Gene flow inbreeding depression and population connectivity in giant kelp Canopy of a giant kelp forest

Gene flow inbreeding depression and population connectivity in giant kelp Canopy of a giant kelp forest

M. pyrifera gametophytes reared in the laboratory

M. pyrifera gametophytes reared in the laboratory

A juvenile Macrocystis plant on a reef

A juvenile Macrocystis plant on a reef

Lead Investigator, Filipe Alberto, after a dive at Mohawk reef

Lead Investigator, Filipe Alberto, after a dive at Mohawk reef

SBC Data Catalog