Disturbance ecology and ecosystem function
How do ecosystems respond to changes in disturbance regimes, such as fire suppression in naturally burning savannas, or more frequent burning in forests that only burned periodically? What fundamental processes govern the responses of ecosystems to these changes, such as the role of soil properties and plant community composition? These are some of the questions that our lab seeks to understand. We ground our work in experimental research, taking advantage of the diverse sets of fire manipulation experiments across the globe combined with the advances in ecosystem models.
The Pellegrini lab is located in the Department of Plant Sciences at the University of Cambridge
New paper published in Ecology Letters where we demonstrate how periodic fire keeps ecosystems resistant to disease and thus helps prevent more severe fires. As the distributions of pathogens change, fire-suppressed forest ecosystems are the most vulnerable to disease spread, rapid mortality, and then subsequently more vulnerable to fire. https://onlinelibrary.wiley.com/doi/full/10.1111/ele.13719
New paper published in Nature Ecology and Evolution using global network of decadal fire manipulations to demonstrate strong effects on tree basal area, stem densities, and plant nutrient use and acquisition strategies. Free access: https://rdcu.be/cfPjH and text link: https://www.nature.com/articles/s41559-021-01401-7
New paper published in Ecological Monographs demonstrating how repeated burning can reduce soil carbon and nitrogen storage and turnover. Measuring extracellular enzymes revealed that fire does not affect all aspects of decomposition equally however, with disproportionate reduction in the acquisition of nitrogen and labile carbon sources. https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/ecm.1409
New paper published in Advances in Ecological Research presenting a conceptual framework and review of how fire affects soils in both the short and long term. We apply the pulse-press framework to understand why the effect of single fires may differ from repeated burning. https://www.sciencedirect.com/science/article/pii/S0065250420300106
Global scope: Our work spans many ecosystems across the globe to try to ascertain generalities in how ecosystems respond to fire, but also using natural variability as a platform to test hypotheses around mechanisms.
African savannas: perhaps nowhere else in the world are ecosystems changing more rapidly than in African savannas. Rapidly changing animal populations due to poaching and fire occurrences due to human population expansion are modifying the landscape tremendously. We study a series of fire manipulation experiments in Kruger National Park to understand how changing fire regimes will affect ecosystems.
South American savannas: wetter than their African counterparts, savannas in the Neotropics receive extraordinary amounts of rainfall, yet still maintain an open and grassy ecosystem, largely due to low soil fertility and frequent burning. Fire activity is rapidly changing in Brazil, potentially threatening biodiversity and changing biogeochemical cycling. Here we also study fire experiments in the Brazilian Cerrado and have established a nutrient fertilization experiment.
Forests in the western United States: Much of the burned area in the United States occurs in western forests dominated by coniferous vegetation, which presents a stark but useful contrast to the response of tropical savannas. Here we work on fire manipulation experiments located in Sequoia and Kings Canyon National Park and different experimental forests outside of Flagstaff Arizona.
Pellegrini, AFA, Hobbie, SE, Reich, PB, Jumpponen, A, Brookshire, ENJ, Caprio, AC, Coetsee, C, Jackson, RB. Repeated fire shifts carbon and nitrogen cycling by changing plant inputs and soil decomposition across ecosystems. Ecological Monographs, doi.org 10.1002/ecm.1409 https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/ecm.1409
Pellegrini, AFA, McLauchlan, K, Hobbie, SE, Mack, M, Marcotte, A, Nelson, D, Perakis, S, Reich, P, Whittinghill, K. (2020) Frequent burning causes large losses of carbon from deep soil layers in a temperate savanna. Journal of Ecology, doi.org/10.1111/1365-2745.13351 https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2745.13351
Pellegrini, AFA, Ahlström, A, Hobbie, S, Reich, P, Nieradzik, L, Staver, AC, Scharenbroch, B, Jumpponen, A, Anderegg, W, Randerson, J, Jackson, R. Fire frequency drives decadal changes in soil carbon and nitrogen and ecosystem productivity. Nature, 2018, 553: 194-198
Pellegrini, AFA, Anderegg, WRL, Paine, CE, Hoffmann, WA, Kartzinel, T, Rabin, SS, Sheil, D, Franco, AC, Pacala, SW. Convergence of bark investment according to fire and climate structures ecosystem vulnerability to future change. Ecology Letters, 2017, 20: 307-316
Pellegrini, AFA, Pringle, RMP, Govender, N, Hedin, LO. Woody plant biomass and carbon exchange depend on elephant-fire interactions across a productivity gradient in African savanna. Journal of Ecology, 105: 111-121
Contact me: Adam Pellegrini firstname.lastname@example.org