Marc Mayes Defends Ph.D. Dissertation in Brown-MBL Graduate Program

Marc Mayes Defends Ph.D. Dissertation in Brown-MBL Graduate Program

By Marc Mayes and Alison Maksym

Marc Mayes, a student in the Brown-Marine Biological Laboratory (MBL) Graduate Program in Biological and Environmental Sciences, successfully defended his Ph.D. dissertation on July 27 at Brown University in Providence, R.I. Mayes’ dissertation was titled, “Forest nutrient cycling and remote sensing of land cover in Miombo Woodlands.”

Mayes is the nineteenth student to graduate with a Ph.D. from the joint Brown-MBL program since 2003. Mayes is a student in the Department of Earth, Environmental and Planetary Sciences (DEEPS) at Brown, and was advised by MBL Ecosystems Center Distinguished Scientist Jerry Melillo, MBL Senior Scientist Chris Neill, and Brown University Professor of Earth, Environmental and Planetary Sciences John Mustard.

Mayes’ dissertation concerned nutrient cycling constraints and satellite remote-sensing approaches for monitoring the regrowth of mature tropical dry forests within the sub-Saharan African Miombo Woodlands. The Miombo extends over 2.5 million square kilometers from Angola to Tanzania, where ecosystems are experiencing increasing pressures from land use, forest resource demands, and climate change. To accomplish his work, Mayes independently organized and led five field campaigns to rural western Tanzania between 2012 and 2015 to collect field data and work with local sustainable development organizations, such as the Millennium Villages Project-Mbola.

Mayes’ projects permitted new characterizations of the nitrogen cycle during forest regrowth. Mayes also developed field-validated, remote-sensing methods to estimate forest biomass trends at landscape scales, based on optical satellite data from sensors such as Landsat.

IMG_0425_mk_mtm_withcalvesWhile working on his dissertation, Mayes was engaged in a number of other applied science activities.  He led a volunteer water quality monitoring program at Brown through the University of Rhode Island Watershed Watch extension program. Mayes also facilitated a new academic -nonprofit collaboration between Brown University undergraduates and the Cambridge, Mass.-based nonprofit EcoLogic, which develops local-scale water infrastructure and forest conservation management plans. As part of this collaboration, Mayes mentored undergraduate students who completed remote sensing projects that analyzed forest cover changes in Ecologic project watersheds.

In February, Mayes was awarded a Presidential Management-STEM Fellowship, which recognizes young scientists with leadership potential, public service orientation, and research and management skills. Ultimately, Mayes aspires to a career in applied ecosystem science research, informing conservation land-use planning and climate change adaptation in Africa and in the United States.

Mayes has accepted a postdoctoral appointment at The Nature Conservancy, where he will work with Kelly Caylor and Lyndon Estes of UC-Santa Barbara and Princeton, respectively, to study the impacts of agriculture and forest use for landscape-scale water and nutrient budgets in sub-Saharan Africa.

Top photo: Mayes exchanges lessons about local land-use practices for instruction on GPS and LiCOR leaf-area measurements at a field site with family owners, Tabora, Tanzania, November 2014. Credit: Ismail Raishidi, Western Zone Agricultural Research Institute at Tumbi, Tabora.

Bottom photo: Mayes takes a break with Makenzie Pumla, a Sukuma herdsman, Tabora, Tanzania, April 2015.  Mayes’ thesis is dedicated in part to Mr. Pumla. Credit: Marc Mayes


Mayes, M.T., J.F. Mustard, and Melillo, J.M. (2015). Forest cover change in Miombo Woodlands: modeling land cover of African dry tropical forests with linear spectral mixture analysis. Remote Sensing of Environment 165: 203-215.

Mayes, M.T., Melillo, J.M., Neill, C.N., Mustard, J.F, Palm, C., and G. Nyadzi.  Nitrogen cycle patterns and slow recuperation during regrowth in a sub-Saharan African tropical dry forest (Miombo Woodland) landscape. Submitted.

Mayes, M.T., Mustard, J.F, Melillo, J.M., Neill, C.N. and G. Nyadzi.  Going Beyond the Green: Senseced Vegetation Material Predicts Basal Area and Biomass in Remote Sensing of Tree Cover Conditions in an African Tropical Dry Forest (Miombo Woodland) landscape.  Submitted.