Richard S. Dodd

Professor
Ph.D.  
  

321 Mulford Hall
Berkeley, California 94720
dodd@berkeley.edu
office: 510-643-1635   lab: 510-643-1635   fax:  510-643-5438

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Research in my laboratory is aimed at understanding how demographic processes give rise to genetic diversity and genetic structure of populations of tree species. Time-scales for our research range from ancient to contemporary. The Pleistocene glaciations had an enormous impact on population demograhics and distribution and the post-glacial period has been characterized by different dispersal and colonization dynamics according to distribution of Pleistocene refugia. Understanding the size and distribution of these refugia and the subsequent colonization dynamics is a focus of our research. Contemporary processes of forest fragmentation on genetic structure of populations is still poorly understood. Elucidating more about the effects of reductions of population size and contiguity is vital for predicting how populations may survive under the changing environmental conditions anticipated by climate change models.

We are working on mangrove evolution and diversity in the Atlantic-east Pacific region. Mangroves are tropical coastal plants adapted to resist high salt concentrations and anaerobic soils, and are known to be of crucial importance to coastal fisheries. Mangrove ecosystems are under threat from land conversion to hotel complexes, salt evaporation ponds, shrimp ponds and from exploitation and pollution. Their protection is an urgent need. The very wide distribution of many mangrove species raises questions of dispersal capabilities. We are studying how population extinctions and colonizations have been affected by changes in sea levels over evolutionary time. We are also modeling how mangroves will respond to future climate change.

In California, we are working on genetic structure and diversity of coastal woodlands, with a focus on oaks(Section Lobatae [red oaks]) and tanoak. This work includes understanding the distribution of Pleistocene refugia and the effects of contemporary fragmentation on population diversity and future viability. Oaks are a classic example of why the biological species concept does not always work well as they hybridize readily. We have focused on hybridization in oaks and the potential role that this plays in dispersal and colonization. The recent epidemic of sudden oak death affecting several species in the California Coast Ranges may have serious consequences for native vegetation. We work with other research groups to assess genetic variation in host species that are susceptible to the disease and also to try to find genetic markers that are correlated with disease resistance. This work is funded by the US Forest Service.

European black pine is a widespread disjunct species. We have already worked on population differentiation from north Africa to the Balkans. Recent interest in the conservation of rare species within the European Union has raised questions as to the status of populations in the Cevennes of south central France. Some of these are mixed with plantings of exotic provenances of this species. We are working on assessing gene flow, using organellar markers, to define exclusion zones needed to protect the native gene pool. Also, in conservation genetics we will be working on the population genetics and systematics of cypress species native to western north America. Several of the species native to California and Mexico are rare or endangered. Fire is an important factor in the ecology of cypresses, and understanding the genotype recruitment process after fire is necessary for predicting population viability.

Colonization of many angiosperm trees is a combination of seed and vegetative reproduction. We are looking at the role of these two processes after disturbance in coastal California species such as tanoak and redwood.

I teach Trees: Taxonomy, Growth and Structure (ESPM 108A). This is a course that focuses on the diversity of tree species and the processes that have led to that diversity and its spatial distribution. Forest Conservation Genetics (ESPM 108B). This course looks at how demographic processes affect genetic diversity and structure and how this can be assessed using molecular methods. Major emphasis is on plant species

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Semaan, M.T., Dodd, R.S. (2008). Genetic variability and structure of the remnant natural populations of Cedrus libani (Pinaceae) of Lebanon. Trees, Genetics and Genomes. 4: 757-766.

Dodd, R.S., Hüberli, D., Mayer, W., Harnik, T.Y., A.-Rafii, Z. and Garbelotto, M. (2008). Evidence for the role of synchronicity between host phenology and pathogen activity in the distribution of Sudden Oak Death canker disease? New Phytologist. 179: 505-514.

Nettel, A., Dodd, R. S., A.- Rafii, Z. and Tovilla-Hernández, C. (2008). Genetic diversity enhanced by ancient introgression and secondary contact in East Pacific Black mangroves. Molecular Ecology. 17: 2680-2690.

Dodd, R.S. and Ong, J. E. (2008). Future of mangrove ecosystems to 2025. In: Aquatic Ecosystem: Trends and Global Perspectives. Polunin NVC, ed.172-187 Cambridge University Press.

Nettel, A., Dodd, R. S., Cid-Becerra, J.A., de la Rosa-Velez, J.(2008). Ten new microsatellite markers for the buttonwood mangrove (Conocarpus erectus L., Combretaceae). Molecular Ecology Resources 8: 851-853

Nettel, A., Dodd, R. S., Cid-Becerra, J.A., de la Rosa-Velez, J.(2008). Development of microsatellite markers for the white mangrove (Laguncularia racemosa C.F. Gaertn., Combretaceae). Conservation Genetics 9: 1037-1038

Dodd, R.S. 2007. Range expansion through pollen dispersal: hybrid studies in California red oaks. International Oaks Journal 18: 42-50.

Nettel, A., and Dodd, R.S. (2006). Drifting propagules and receding swamps; genetic footprints of long–distance dispersal and Quaternary extinction along tropical coasts. Evolution 61: 958-971

Morris V.R.F. and R.S. Dodd, R.S. (2006). Characterization of microsatellite markers for the tanoak tree Lithocarpus densiflorus Molecular Ecology Notes. 6: 706-708.

A.- Rafii, and Dodd, R.S. (2006). Chloroplast DNA supports a hypothesis of glacial refugia over post-glacial recolonization in disjunct populations of black pine (Pinus nigra) in western Europe. Molecular Ecology 16: 723-736

Nettel, A., Rafii, F. and R.S. Dodd, R.S. (2004) Characterization of microsatellite markers for the mangrove tree Avicennia germinans L (Avicenniaceae). Molecular Ecology Notes. 5: 103-105.

Dodd, R.S., Hüberli, D., Douhovnikoff, V., Harnik, T.Y., Afzal-Rafii, Z. and Garbelotto, M. (2004). Is variation in susceptibility to Phytophthora ramorum correlated with population genetic structure in coast live oak (Quercus agrifolia Née)? New Phytologist. 165: 203-214.

Douhovnikoff, V, McBride, J.R.M. and Dodd, R.S. (2004). Salix exigua clonal growth and population dynamics in relation to disturbance regime variation. Ecology. 86: 446-452.

Douhovnikoff, V., Cheng, A. and Dodd, R.S. (2004). Incidence, size and spatial structure of clones in second growth stands of coast redwood, Sequoia sempervirens (Cupressaceae). American Journal of Botany. 91: 1140-1146.

Dodd, R.S. and A.- Rafii, Z. 2003. Selection and dispersal in a multispecies oak hybrid zone. Evolution. 58: 261-269.

Dodd, R.S. and Poveda, M. 2003. Environmental gradients and population divergence contribute to variation in cuticular wax composition in Juniperus communis. Biochemical Systematics and Ecology. 31: 1257-1270.

Dodd, R.S. and Kashani, N. 2003. Molecular differentiation and diversity among the California red oaks section Lobatae. Theoretical and Applied Genetics. 107: 884-892.

Douhovnikoff, V. and Dodd, R.S. 2003. Intra-clonal variation and a similarity threshold for identification of clones: application to Salix exigua using AFLP molecular markers. Theoretical and Applied Genetics 106: 1307-1315.

Dodd, R.S., A.-Rafii, Z., Kashani, N, and Budrick J. 2002. Land barriers and open oceans: effects on gene diversity and population structure in Avicennia germinans L. (Avicenniaceae). Molecular Ecology 11:1327-1338.

Dodd, R.S., Afzal-Rafii, Z. 2002 Evolutionary genetics of mangroves: continental drift to recent climate change. Trees: Structure and Function 16:80-86.

Dodd, R.S. and A.-Rafii, Z. 2000. Habitat-related adaptive properties of plant cuticular lipids. Evolution 54: 1438-1444.

Dodd, R.S., A.-Rafii, Z. and Bousquet-Mélou, A. 2000. Evolutionary divergence in the pan Atlantic mangrove Avicennia germinans. New Phytologist 145:115-125.