Ricardo Holdo

Graduate Program Faculty

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Prospective Graduate Students

I am recruiting motivated Master’s or Ph.D. students with an interest in applying rigorous quantitative tools to solving ecological problems, and a desire to become independent, critical thinkers. I hope that graduate students in my lab will be interested in combining a range of approaches (field, lab, remote sensing and/or modeling tools) to tackle their research questions. I am currently looking for students for the Fall 2018 semester to work in two potential areas: 1) an NSF-funded project examining spatial processes in savanna vegetation in Serengeti; 2) a study of tree-grass responses to climate change in South Africa.

Opportunities for Undergraduate Research

I am interested in bringing committed undergraduates who would like to be exposed to new research opportunities into my lab. If you are interested in ecology or environmental sciences and are looking for research opportunities, get in touch with me.

Research Interests

Current research:

  • Mechanisms of tree recruitment limitation in Serengeti National Park, Tanzania
  • Spatial processes and tree recruitment in savannas
  • Ecohydrological drivers of tree-grass dynamics
Selected Publications

Ketter, B.M. and Holdo, R.M. 2018. Strong competitive effects of African savanna C4 grasses on tree seedlings do not support rooting differentiation. Journal of Tropical Ecology, in press.

Holdo, R.M., Nippert, J.B. and Mack, M.C. 2017. Rooting depth varies differentially in trees and grasses as a function of mean annual rainfall in an African savanna. Oecologia 186:269–280. Link to paper.

Campbell, T.A. and Holdo, R.M. 2017. Competitive response of savanna tree seedlings to C4 grasses is negatively related to photosynthesis rate. Biotropica 49:774–777. Link to paper.

Rugemalila, D.M., Morrison, T.A., Anderson, T.M. and Holdo, R.M. 2017. Species-specific trade-offs drive variability in seed production, infestation and viability in Acacia tortilis and Acacia robusta in Serengeti National Park. Plant Ecology 218:909-922.

Twine, W.C. and Holdo, R.M. 2016. Fuelwood sustainability revisited: integrating size structure and resprouting into a spatially realistic fuelshed model. Journal of Applied Ecology 53:1766-1776. Link to paper.

Rugemalila, D.M., Anderson, T.M. and Holdo, R.M. 2016. Precipitation and elephants, not fire, shape tree community composition in Serengeti National Park, Tanzania. Biotropica 48:476-482. Link to paper.

Morrison, T.A., Anderson, T.M., and Holdo, R.M. 2016. Elephant damage, not fire or rainfall, explains mortality of overstorey trees in Serengeti. Journal of Ecology 104:409-418. Link to paper.

Holdo, R.M. and Nippert, J.M. 2015. Transpiration dynamics support resource partitioning in African savanna trees and grasses. Ecology 96:1466-1472. Highlighted in Nature Plants (DOI: 10.1038/nplants.2015.102). Link to paper.

Nippert, J.B. and Holdo, R.M. 2015. Challenging the maximum rooting depth paradigm in grasslands and savannas. Functional Ecology 29:739-745. Link to paper.

Holdo, R.M. and Brocato, E.R. 2015. Strength of tree-grass competition is strongly species-dependent. Plant Ecology 216:577-588. Link to paper.

Holdo, R.M. Socio-ecological dynamics and feedbacks in the Greater Serengeti. 2015. Book chapter in Serengeti IV: Sustaining biodiversity in a coupled human-natural system. Sinclair, A.R.E., Mduma, S.A.R., and Packer, C. (eds.). Chicago University Press.

Eby, S., Holdo, R.M., Metzger, K., and Dempewolf, J. 2015. Structural, functional and biodiversity consequences of fire in the Serengeti. Book chapter in Serengeti IV: Sustaining biodiversity in a coupled human-natural system. Sinclair, A.R.E., Mduma, S.A.R., and Packer, C. (eds.). Chicago University Press.

Hopcraft, G., Fryxell, J.M., and Holdo, R.M. 2015. Why are wildebeest the most abundant herbivore in the Serengeti ecosystem? Book chapter in Serengeti IV: Sustaining biodiversity in a coupled human-natural system. Sinclair, A.R.E., Mduma, S.A.R., and Packer, C. (eds.). Chicago University Press.

Anderson, T.M., Morrison, T., Rugemalila, D.M. and Holdo, R.M. 2014. The composition of savanna canopy trees and their recruitment pool are decoupled across a demographic bottleneck in the Serengeti ecosystem. Journal of Vegetation Science 26:385-394. Link to paper.

Holdo, R.M., Anderson, T.M. and Morrison, T. 2014. Precipitation, fire and shifting demographic bottlenecks in Serengeti tree populations. Landscape ecology 29:1613-1623. Link to paper.

Holdo, R.M. and Mack, M.C. 2014. Functional attributes of savanna soils: contrasting effects of tree canopies and herbivores on bulk density, nutrients and moisture dynamics. Journal of Ecology 102:1171-1182.

Arnold, S.G., Anderson, T.M., and Holdo, R.M. 2014. Edaphic, nutritive, and species assemblage differences between hotspots and matrix vegetation: two African case studies. Biotropica 46(4): 387–394.

Holdo, R. M. 2013. Revisiting the Two-Layer Hypothesis: Coexistence of Alternative Functional Rooting Strategies in Savannas. PLoS ONE 8: e69625.

Gaughan, A.E., Holdo, R.M. and Anderson, T.M. 2013. Using short-term MODIS time-series to quantify tree cover in a highly heterogeneous African savanna. International Journal of Remote Sensing 34:6865-6882.

Holdo, R.M. 2013. Effects of fire history and N and P fertilization on seedling biomass, Specific Leaf Area, and root:shoot ratios in a South African savannah. South African Journal of Botany 86:5-8.

Holdo, R.M., Holt, R.D., and Fryxell, J.M. 2013. Herbivore-vegetation feedbacks can expand the range of savanna persistence: insights from a simple theoretical model. Oikos 122: 441–453.

Holdo, R.M. and Roach, R.R. 2013. Inferring animal population distributions from individual tracking data: theoretical insights and potential pitfalls. Journal of Animal Ecology 82: 175–181.

Holdo, R.M., Mack, M.C., and Arnold, S.G. 2012. Tree canopies explain fire effects on soil nitrogen, phosphorus, and carbon in a savanna ecosystem. Journal of Vegetation Science 23:352-360.

Holdo, R.M., Fryxell, J.M., Sinclair, A.R.E., Dobson, A.P., Holt, R.D. 2011. Predicted impact of barriers to migration on the Serengeti wildebeest population. PLoS ONE 6(1): e16370.

Holdo, R.M., Sinclair, A.R.E., Holt, R.D., Godley, B., and Thirgood, S. 2011. Migration impacts on communities and ecosystems: empirical evidence and theoretical insights. Chapter 9 in Animal Migration: A Synthesis. Milner-Gulland, E.J., Fryxell, J.M., and Sinclair, A.R.E. (eds.). Oxford University Press.

Borger, L., Matthiopoulos, J., Holdo, R.M., Couzin, I., and Morales, J. 2011. Migration quantified: constructing models and linking them with data. Chapter 8 in Animal migration: a synthesis. Milner-Gulland, E.J., Fryxell, J.M., and Sinclair, A.R.E. (eds.). Oxford University Press.

Holt, R.D., Holdo, R.M., and van Veen, F.J. 2010. Theoretical perspectives on trophic cascades: current trends and future directions. Pp. 301-318 in Trophic cascades: predators, prey, and the changing dynamics of nature. Terborgh, J., and Estes, J.A. (eds.). Island Press.

Holdo, R.M., Holt, R.D., Galvin, K., Polasky, S., Knapp, E., and Hilborn, R. 2010. Responses to alternative rainfall regimes and antipoaching enforcement in a migratory system. Ecological Applications 20:381-397.

Holdo, R.M., Sinclair, A.R.E., Metzger, K.L., Bolker, B.M., Dobson, A.P., Ritchie, M.E., and Holt, R.D. 2009. A disease-mediated trophic cascade in the Serengeti: implications for ecosystem C. PLOS Biology 7:e1000210. Summarized in Research Highlights (“Wildebeest chain reaction”), Nature 461:700.

Holdo, R.M., Holt, R.D., and Fryxell, J.M. 2009. Opposing rainfall and nutrients gradients best explain the wildebeest migration in the Serengeti. The American Naturalist 173:431-445.

Holdo, R.M., Holt, R.D., and Fryxell, J.M. 2009. Grazers, browsers, and fire influence the extent and spatial pattern of tree cover in the Serengeti. Ecological Applications 19:95-109.

Holdo, R.M. and Timberlake, J. 2008. Rooting depth and above-ground community composition in Kalahari sand woodlands in western Zimbabwe. Journal of Tropical Ecology 24:169-176.

Holdo, R.M. 2007. Elephants, fire, and frost can determine community structure and composition in Kalahari woodlands. Ecological Applications 17:558-568.

Holdo, R.M., Holt, R.D., Coughenour, M.B., and Ritchie, M.E. 2007. Plant productivity and soil nitrogen as a function of grazing, migration, and fire in an African savanna. Journal of Ecology 95:115-128.

Chamaille-Jammes, S., Fritz, H., and Holdo, R.M. 2007. Spatial relationship between elephant and sodium concentration of water disappears as density increases in Hwange National Park, Zimbabwe. Journal of Tropical Ecology 23:725-728.

Holdo, R.M. 2006. Elephant herbivory, frost damage, and topkill in Kalahari sand woodland savanna trees. Journal of Vegetation Science 17:509-518.

Holdo, R.M. 2006. Tree growth in an African woodland savanna impacted by disturbance. Journal of Vegetation Science 17:369-378.

Holdo, R.M. 2005. Stem mortality following fire in Kalahari sand vegetation: effects of frost, prior damage, and tree neighbourhoods. Plant Ecology 180:77-86.

Zavala, M.A. and Holdo, R.M. 2005. Delayed effects of fire on habitat use by large herbivores in Acacia drepanolobium savanna. African Journal of Ecology 43:155-157.

Holdo, R.M., and McDowell, L.R. 2004. Termite mounds as nutrient-rich food patches for elephants. Biotropica 36:231-239.

Holdo, R.M. 2003. Woody plant damage by African elephants in relation to leaf nutrients in western Zimbabwe. Journal of Tropical Ecology 19:189-196.

Holdo, R.M., Dudley, P.J., and McDowell, L.R. 2002. Geophagy in the African elephant in relation to availability of dietary sodium. Journal of Mammalogy 83:652-664.