Howard R. Lasker

Evolutionary Biology and Ecology; Population Ecology of Marine Invertebrates

Professor

Ph.D 1978 University of Chicago
Postdoc (78) University of Miami
Assistant Professor 1979;
Associate Professor 1986;
Professor 1994 University at Buffalo

 


Address Information

Howard R. Lasker
Department of Biological Sciences
637 Hochstetter Hall
State University of New York at Buffalo
Buffalo, NY 14260

(716) 645-2363 ext: 184

To send e-mail: hlasker@acsu.buffalo.edu


For our Lab Web Page please click here


RESEARCH SUMMARY

Population ecology of Pseudopterogorgia elisabethae. - Pseudopterogorgia elisabethae is a common gorgonian of coral reefs throughout the Caribbean. Colonies are harvested for a pseudopterosin, a natural product that has anti-inflammatory properties and which is used as a topical agent in cosmetics. We are studying and modeling the population ecology of P. elisabethae focusing on those parameters crucial to the development of a management plan. The project encompasses studies of the species recruitment, growth and survivorship. We are also studying P. elisabethae population genetics as well as developing methods for colony propagation that can be used in mariculture. A larger and more general goal of the project is to identify the parameters that must be incorporated in analyses of coral populations and determine whether there are ''ecologic profiles'' that can be used to differentiate species that should be highly protected from those for which managed harvesting is ecologically sound.

Evolution and development of colony form among gorgonian corals. Form affects the manner in which benthic taxa extract resources from the environment, resist physical disturbance and interact with competitors and predators. Understanding how form develops and varies within individuals over their life spans, between individuals across habitats and among species is a crucial component to understanding sessile taxa and their interactions with their environment and other biota. Using gorgonian corals as a model system I am conducting a multi-level analysis of colony form. The research focuses on models that address the question, “How are colonies organized?” Descriptive models along with a series of manipulative experiments are being used to determine which features of branches best characterize their future growth and branching behavior.
Gorgonians like most colonial taxa have highly plastic colony forms. Is that plasticity produced by the local environment interacting with assembly rules that are themselves invariant or do assembly rules change as a function of the local environment and the colony's history? These questions are being investigated using observational data and manipulative experiments.

Fertilization success among broadcast spawning benthic invertebrates. - Analyses of marine invertebrate life history strategies have generally ignored fertilization rates as a factor in the organism's life history, and most studies have implicitly assumed high fertilization rates. Our data (Lasker et al. 1996) on Caribbean gorgonians are among the few data on in situ fertilization rates for a broadcast spawning species. Fertilization rates of eggs vary from 0 to near 100% on different nights and different spawning events. The variance between sites and times is enormous, but much of the time many eggs go unfertilized. This result has now been verified in four different species in reefs in both Panama and the Florida Keys. The presence of sperm limitation among broadcast spawning species suggests a variety of reproductive strategies that may be pursued by colonies and also suggests dichotomies between male and female colonies. We are examining fertilization strategies among gorgonians using a combination of fertilization success models, data ib in situ fertilization and genetically determined paternity of larvae produced in natural spawning events.


Photographs of a Pseudopterogorgia elisabethae colony from San Salvador, Bahamas. The replicate photos are used to measure growth rates and determine the resilience of the species to harvesting.


PUBLICATIONS

  • Lasker H.R. and Sanchez J.A.
    Astogeny and allometry of modular colonial organisms.
    In: R.N. Hughes (ed.), Progress in Asexual Propagation and Reproductive Strategies. John Wiley (Oxford-IBH, India).) In press
  • Beiring, E.A. and Lasker, H.R.
    Egg production by colonies of a gorgonian coral.
    Marine Ecology Progress Series 196:169-177(2000)
  • Kapela, W. and Lasker, H.R.
    Size dependent reproduction in the Caribbean gorgonian Pseudoplexaura porosa.
    Marine Biology 135:107-114 (1999)
  • Lasker, H.R. and Coffroth, M.A.
    Responses of clonal reef taxa to environmental change.
    American Zoologist 39:92-103. (1999)
  • Lasker, H.R., Kim, K and Coffroth MA.
    Production, survival and recruitment of a plexaurid gorgonian.
    Marine Ecology Progress Series. 162:111-123 (1998)
  • Kim, K. and H.R. Lasker.
    Allometry of resource capture and constraints on modular growth.
    Functional Ecology 12:646-654 (1998)
  • Coffroth, M.A. and Lasker, H.R.
    Population structure of a clonal gorgonian coral: the interaction between vegetative propagation and disturbance.
    Evolution 52:379-383. (1998)
  • Lasker, H.R., Brazeau, D.A., Calderon, J., Coffroth, M.A., Coma, R.C. and Kim, K.
    In situ rates of fertilization among broadcast spawning gorgonians.
    Biological Bulletin 190:45-55 (1996)

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