FACULTY
DIRECTORY

 

GRADUATE
DIRECTORY

STAFF DIRECTORY
ALL PEOPLE DIRECTORY
 
 
CAMPUS MAP
 
photo Carol Horvitz
Professor
email
190  Cox Science Center, Dept. of Biology
1301 Memorial Drive, Coral Gables, FL 33124

phone (305) 284-5364
fax (305) 284-3039
laboratory website
Biologal Invasions Researcher Database



  
 
Education and professional experience
  • B.A.  (Environmental Studies), 1972, Antioch College, Yellow Springs, Ohio
  • Ph.D. (Biology), June 1980, Northwestern University, Evanston, Illinois
  • Jean Andrews Visiting Professor of Botany, University of Texas, Austin, Texas.  February, 1999.
  • Pole de Recherches et Innovations de Angers (PRIA). 10th Invited Professor Chair. Institut National d’Horticulture. Angers, France.  August, 1999 – February, 2000
Recent Grants
  • 2006   NSF OPUS: Plant-animal interactions and stochastic population dynamics of understory plants in tropical forests. 24 mos. 9/01/06-8/31/08. Sole PI. $106,200.33.
  • 2005   Institute for Museum and Library Services (IMLS). Lifelong learning project needs created by the 2005 hurricane season at the Gifford Arboretum. 14 mos.  4/01/06-5/31/07. Sole P.I. $52,329..
  • 2005   Institute for Museum and Library Services (IMLS). Conservation needs created by the 2005 Hurricane Season at the Gifford Arboretum.12 mos. 2/15/06-2/14/07. Sole P.I. $11,593.
  • 2005   NSF. USDA-NSF Interagency PI Meeting (October 17&18, 2005). Role of Applied and Basic Research in the Management of Biological Invasions. 12 months. 8/15/05 – 8/14/06. $30,010. see
    Biologal Invasions Researcher Database
  • 2004   USDA Agricultural Research Service. Center for Aquatic and Invasive Plants. The impact of weevils and psyllids on seedling fates and population dynamics of Melaleuca in different habitats: combining experimental data with population projection matrix models. $95,000/3yr. 8/15/04-8/14/07
  • National Science Foundation. Conference on Invasive Plants in Natural and Managed Ecosystems and 7th International Conference on Ecology and Management of Alien Plant Invasions. I am the P.I. of this grant, with a co-P.I. at ESA, Clifford Duke. $34,000 9/1/2003-8/31/2005.
  • National Institute on Aging. NIH. The biodemography of life span (with P.I., Program Director James Carey). Project #5. Evolutionary dynamics of life span. as co-P.I. to Shripad Tuljapurkar.  Total Grant is over $1,000,000. My portion is a subcontract to UM $141,538 9/15/2003-9/14/2008.
Areas of Focus
  • Conservation and Restoration Biology
  • evolutionary biology
  • mathematical and theoretical biology
  • tropical biology
Research Interests
My research is at the interface of empirical and theoretical ecology.  I am a plant population ecologist with a deep interest in how plants cope with spatial and temporal variability in the environment.  This interest leads me inexorably to work in the areas of stochastic demography (population dynamics and life history of organisms in temporally varying environments) and spatial population dynamics (the movements of individuals among patches and the expansion of populations across space).  Evolutionary ecology of life span, plant-animal interactions, dispersal biology, disturbance biology and invasion biology comprise focal areas of my current research program.  I am interested in currencies of population dynamics that link ecology to evolution: the stochastic growth rate measures fitness in variable environments and selection must act through it.  I am interested in applied aspects as well: what is the impact of biocontrol agents on the population dynamics of invasive species?  Geographically, most of my empirical work has been in the tropics and subtropics, including Mexico, Central America and extreme southern Florida.  Taxonomically, much (but not all) of my work has been focused in the Marantaceae in the tropics or on Ardisia spp in Florida.  I have broad knowledge of tropical plants (I have been the pro-bono Director of the Gifford Arboretum at UM for many years) and specialized knowledge about the animals (especially insects) that interact with the plants I study, including ants, butterflies, beetles and some avian seed dispersers.  I am fascinated by the diversity of ways that organisms have of coping with the abiotic and biotic world they inhabit.Since the organisms I study ultimately experience time and space on scales much larger than I can readily measure, modeling is an important tool for understanding what is going on. 

Also, every lifetime is a realization of a probabilistic or stochastic process; each realization is a sample path out of the many possible paths that could unfold from the same process; by process I mean a set of probability rules that governs a sequence of events: including events in the life cycle, like birth, death, and growth, or events in the environment, like tree fall gaps and gap-phase regeneration.  It is imperative to learn to think stochastically to understand ecology in nature.  Thus, in addition to collecting detailed data in natural populations in the field, I also explore the universe through modeling, putting my data into the context of larger extents of time and space than I could ever physically observe.  By working closely with theoreticians (Caswell, Tuljapurkar and his lab group), I am a partner in the development of new analytical tools.  It is our experience that in application of theory to data, new theoretical issues arises, as do new empirical issues.  There is feedback in both directions and science makes a little step forward.  The interactive process between theory and data is very rewarding and fascinating.
Teaching Philosophy
I have 20 years of experience teaching ecology to undergraduate and graduate students, both field ecology and mathematical ecology.  Fortunately, we have some of the most interesting natural areas and organisms just outside the building in Miami and we have the tropics nearby.  The heart of my teaching philosophy is to get students engaged in discovery and to create interactive hands-on learning opportunities.  What is great about teaching ecology is the interplay of field studies and mathematical thinking.  Getting students to wake-up to the connection between empirical nature and disciplined abstract thinking (i.e. theory) is the ongoing challenge.  It is exceptionally exciting to see them make this connection, but rather rare.  Along the way, fortunately there are many “aha!” moments that one can facilitate that range from close encounters with real organisms to appreciation of the biological significance of eigenvalue sensitivity for a study organism.  Just getting students to learn how to look at plants (ants, birds, wasps…) in a way that will help them tell one from another is fun.  Undergrads are truly impressed when they open a fig under a dissecting scope and are overrun by dozens of tiny emerging wasps.  The fig is from a tree just outside the building that they never even noticed before; certainly they never dreamed of the drama taking place there and that they could use it to explore the theory of sex ratios in wasps!  On the other side of the spectrum, a grad student finds out that he has just been able to determine the relative importance of raccoons vs catbirds as dispersal agents of an exotic shrub in the Everglades by applying to his dissertation data an elasticity analysis of wavespeed developed recently by Mike Neubert and Hal Caswell.  A very cool and novel use of a relatively new theoretical tool.  This is a deeper kind of connection that fuses the empirical with the theoretical in new ways to step the field of science forward and actually has management implications.  Teaching in this sense is more like bearing witness to the growth of the students as scientists, the most rewarding moments.

Undergrad Ecology  For many years, I have taught the undergrad ecology lecture and two lab sections (for the labs, I supervise the TA’s who do most of the work, although I lead some of the field trips and outdoor labs).  The lab includes a series of field, lab and computer exercises developed over the years.  A current cornerstone experience of the lab is writing a scientific paper on one central experiment that the students carry out over a number of weeks; students are walked through and graded on each phase of the process, including a peer review. 

Graduate Field Ecology Every other spring for many years, have been teaching Advanced Field Ecology.  This course includes one long (10 d) field trip and a several short (0.5-2 d) trips.  A book is produced that includes papers written about the different research projects carried out during the semester.  The papers are written up as formal scientific articles and include the appropriate statistical analyses for each project.  Team work, framing testable hypotheses and collecting data that answer a question as well as learning organisms and habitats are emphasized.  Students share the logistics, cooking, camping and academic duties.  I recruit resource faculty from my own department plus scientists at the sites we visit.

Graduate Theoretical Ecology Every other year, for many years, I had been teaching a course in theoretical ecology for biology graduate students.  The students made many presentations of their homework in class.  The basic philosophy is “the only way to learn math is to do math” and “to see what an equation does, put some numbers in and watch it behave.”  Recently the course morphed into a new 2-semester-long course.  Together with colleagues from math, I taught the new course to graduate students from biology, math and marine science.  The goal of the new course is to create enough common language that mathematically-trained and empirically-trained students can learn to work together in teams to apply mathematical thinking to ecological issues.  This will become the core course of the new graduate program in theoretical ecology at the University of Miami while at the same time still serving the more general constituents of the graduate program in biology, who want to learn the basics of theory, modeling and programming for their own work in population, community or ecosystem ecology.

Graduate short courses on matrix modeling of population dynamics. I was invited to teach at Uppsala University, Sweden, at Pymatuning Field Station (University of Pittsburgh) and at Kellogg Biological Station (Michigan State University) and have been invited to run another one at Uppsala University, Sweden next March.  I have been a guest lecturer on matrix models in another special course given by Stockholm University in Sweden.

Graduate field courses on tropical biology for Latin American students.  I have been a resource person, run field problems and lectured in Spanish in the OTS courses for Latin American graduate students in Costa Rica and in Peru.
Selected Publications
  • Morris, W.F., S. Tuljapurkar, C.V. Haridas, E.S. Menges, C.C. Horvitz, and C.A. Pfister, in press. Sensitivity of the population growth rate to demographic variability within and between phases of the disturbance cycle. Ecology Letters.
  • Tuljapurkar, S. and C.C. Horvitz. 2006. From stage to age in variable environments: life expectancy and survivorship.  Ecology. 87: 1497-1509
  • Boyce, M.S., C.V. Haridas, C.T. Lee and the NCEAS Stochastic Demography Working Group. 2006 Demography in an increasingly variable world.  TRENDS in Ecology and Evolution. 21: 141-148.
  • Horvitz, C.C., S. Tuljapurkar, J.B. Pascarella. 2005. Plant-animal interactions in random environments: habitat-stage elasticity, seed-predators and hurricanes.  Ecology 86: 3312-3322.
  • Koop, Anthony and C.C. Horvitz. 2005. Projection matrix analysis of the demography of an invasive, non-native shrub (Ardisia elliptica).  Ecology 86:2661-2672.
  • LeCorff, J. and C.C. Horvitz. 2005. The contrasting roles of chasmogamous and cleistogamous reproduction in population growth and population spread in an ant-dispersed neotropical herb, Calathea micans (Marantaceae). Ecological Modelling 188: 41-51.
  • Johnson, D.M. and C.C. Horvitz. 2005. Estimating natal dispersal: tracking the unseen dispersers. Ecology 86: 1185-1190.
  • D’Antonio, C.M., N.E. Jackson, C.C. Horvitz, and R. Hedberg. 2004. Invasive plants in wildland ecosystems: merging the study of invasion processes with management needs. Frontiers in Ecology and the Environment 2: 513-521.
  • Tuljapurkar, S., Horvitz, C.C. and J. Pascarella, 2003. The many growth rates and elasticities of populations in random environments. American Naturalist. 162: 489-502.
  • Horvitz, C.C., M. A. Pizo, B. Bello y Bello, J. LeCorff and R. Dirzo. 2002. Are plant species that need gaps for recruitment more attractive to seed-dispersing birds and ants than other species?  In. D.J. Levey, W. R. Silva and M. Galetti (eds.) Seed dispersal and frugivory: ecology, evolution and conservation. CAB International Press. Oxon, UK.
  • Horvitz, C. C. and A. Koop. 2001. Removal of non-native vines and post-hurricane recruitment in  tropical hardwood forests of Florida. Biotropica 33: 268-281
  • Horvitz, C. C., J. B. Pascarella, S. McMann, A. Freedman, and R. H. Hofstetter. 1998. Functional roles of invasive non-indigenous plants in hurricane-affected subtropical hardwood forests. Ecological Applications: 8: 947-974.
  • Pascarella, J. B. and C. C. Horvitz. 1998. Hurricane disturbance and the population dynamics of a tropical understory shrub: megamatrix elasticity analysis: Ecology 79: 547-563.
  • Horvitz, C.C. and D.W. Schemske. 1995. Spatiotemporal variation in demographic transitions for  a tropical understory herb: projection  matrix analysis. Ecological Monographs.  65:155-192.
  • Horvitz, C.C. 1991. Light environments, stage structure and dispersal syndromes of Costa Rican Marantaceae. Ant-Plant Interactions, ed. C.R. Huxley and D.F. Cutler, pp.463-485. Oxford University Press. New York.
  • Schemske, D.W. and C.C. Horvitz. 1989. Temporal variation in selection on a floral character of a neotropical herb, Evolution  43:461-464.
  • Horvitz, C.C. and D.W. Schemske. 1986. Seed dispersal and environmental heterogeneity in a neotropical herb: A model of population and patch dynamics. In Symposium on frugivores and seed dispersal . (A. Estrada and T.H. Fleming, eds.) Dr. W. Junk Publishers, Dordrecht, Netherlands.  pp. 169-186.
 
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