Map of the world

Theory at the service of conservation


About

Tanjona

I am a Malagasy ecologist and develop mathematical and statistical models to better understand patterns and processes of biodiversity loss.

I obtained a MSc in applied mathematics with Arthur Randrianarivony at the University of Antananarivo. I did a PhD with Ilkka Hanksi and Otso Ovaskainen at the University of Helsinki. I completed a first postdoc with Emma Goldberg at the University of Minnesota, and a second postdoc with Anthony Ives and Monica G. Turner at the University of Wisconsin-Madison (ACES), and is doing a third postdoc with Benjamin Roche at the University of Montpellier on COVID-19 modeling. I am currently a lecturer at the department of Life Science and department of Mathematics at the University of Fianarantsoa. I am also a Honorary Fellow at the University of Wisconsin-Madison.


Research

I work at the interface of theoretical ecology and conservation biology. I assess the role of environmental variability, spatial processes, and species interactions to understand stability and resilience of ecosystems. My work spans various continents: Asia, Europe, Northern America, and Madagascar, and involves topics such as phylogeography, paleoecology, and contemporary ecology. My research are generally motivated by conservation related questions in Madagascar.
habitat destruction in Madagascar

Habitat destructions and landscape heterogeneity

I use and combine the strength of spatial ecology and landscape ecology for applications in conservation biology to:

  • Quantify the loss of habitat quality, quantity, and fragmentation in Madagascar
  • Elaborate on how species-area relationship (SAR) and its derivatives can be used to estimate biodiversity loss

    • thermal performance curve

    Species' niche

    Niche is a central ecological concept that characterizes how a species responds to the environment and thus for its conservation. I am currently

  • using metabolic theory to understand thermal performance curve
  • characterzing the limits of various regeneration strategies to distrubance regime

    • extinction threshold as a function of niche breadth

    Stochastic processes

    Stochasticity can be more than a noise in shaping biodiversity patterns, I aim to:

  • Assess the relative role of deterministic and stochastic processes for community assembly, stability, and resilience
  • Diversify the type of stochastic processes used in models

    • phylogenetic pattern

    Miscellaneous

    I am broadly interested in method developments, from phylogenetic comparative methods to pragmatic statistical approach to optimize fungal spores counting. I have been analyzing large spatiotemporal data: crop yield in the USA, evolution of malaria in Madagascar, and influence of political instability on the economy of Madagascar. If it isn't obvious yet, I am always excited to venture into new projects.


    Publications and in prep.

    Published

    • Ramiadantsoa, T. and C. L. Solofondranohatra. Nontrivial responses of vegetation to compound disturbances : a case of Malagasy grassland. In press in Malagasy Nature.
    • Rasambainarivo, F., ..., T. Ramiadantsoa, ..., Rice, B. L. Monitoring for outbreak-associated excess mortality in an African city: Detection limits in Antananarivo, Madagascar. International Journal of Infectious Diseases, 103, 338-342.
    • Rice, B. L., ..., T. Ramiadantsoa, ..., Metcalf, C. J. E. Variation in SARS-CoV-2 outbreaks across sub-Saharan Africa. Nature Medicine, 27(3), 447-453.
    • McCary, M.A., J. Phillips, T. Ramiadantsoa, L.A. Nell, A.R. McCormick, J.C. Botsch. Transient top-down and bottom-up effects of resources pulsed to multiple trophic levels. Ecology, 102(1): e03197.
    • Kucharick, C.J., T. Ramiadantsoa, J. Zhang, A.R. Ives. Spatiotemporal trends in crop yields, yield variability, and yield gaps across the USA. Crop Science, 60(4), 2085-2101
    • Ramiadantsoa, T. , M.A. Stegner, J.W. Williams, and A.R. Ives. 2019. The potential role of intrinsic processes in generating abrupt and quasi-synchronous tree declines during the Holocene. Ecology, 100(2): e02579
    • Ramiadantsoa, T. , I. Hanski, and O. Ovaskainen. 2018. Responses of Generalist and Specialist Species to Fragmented Landscapes. Theoretical Population Biology. 124:31-40.
    • Ratajczak, Z., S.R. Carpenter, A.R. Ives, C.J. Kucharik, T. Ramiadantsoa, M. A. Stegner, J. W. Williams, J. Zhang, and M.G. Turner. 2018. Abrupt Change in Ecological Systems: Inference and Diagnosis. Trends in Ecology & Evolution, Volume 33, Issue 7.
    • Ihantamalala, F. A., F.M.J. Rakotoarimanana, T. Ramiadantsoa, J.M. Rakotondramanga, G. Pennober, F. Rakotomanana, S. Cauchemez, C.J.E. Metcalf, V. Herbreteau, and A. Wesolowski. 2018. Spatial and temporal dynamics of malaria in Madagascar. Malaria Journal 17, no. 1: 58.
    • Ramiadantsoa, T., J. Sirén, and I. Hanski. 2017. Phylogenetic comparative method for geographical radiation. Annales Zoologica Fennica Vol. 54. No. 1–4 (special issue in honor of Ilkka Hanski).
    • Ramiadantsoa, T., O. Ovaskainen, J. Rybicki, and I. Hanski. 2015. Large-scale habitat corridors for biodiversity conservation: A forest corridor in Madagascar. PloS ONE 10: e0132126.

    Submitted and in prep.

    Abbott, K. C.,..., T. Ramiadantsoa, ..., Twombly, S.The Ever-Increasing Need for Theory. Under revision for Biology Letters.

    T. Ramiadantsoa, ..., Rasambainarivo, F. Existing human mobility data sources poorly predicted the spatial spread of SARS-CoV-2 in Madagascar. Under review for Epidemics.

    Rasambainarivo, F., T. Ramiadantsoa,..., Metcalf C.J.E. Prioritizing COVID-19 vaccination efforts and dose allocation within Madagascar. Submitted to BMC Public Health

    Ramiadantsoa, T., Z. Ratajczak, M.G. Turner. A Goldilocks model for the response of fire-prone forests to changing fire regime: a case study of Yellowstone Nation Park. Under revision for Ecology.

    Culbertson, K., Mondragon-Botero, A., Treuer, T., T. Ramiadantsoa, Reid, L. The Eco-Evolutionary History of Madagascar presents Unique Challenges to Tropical Forest Restoration. In prep. for Biotropica

    DeAngelis, D., ... , T. Ramiadantsoa,..., Fortin M. J. Theory to integrate internal ecological processes and external driving forces: What we know versus what we think we know. In prep.

    Ramiadantsoa, T. and A.R. Ives. Consequences of the structure of environmental variability on population and community stability. In prep. for Ecology Letters.

    Ramiadantsoa, T. and E.E. Goldberg. Exploring the role of body size in shaping thermal performance of insects.

    Perrotti, A.G., M. Traschel, T. Ramiadantsoa, ..., J.W. Williams. Optimal counting methods for coprophilous fungal spore analysis.

    Rakotoarivelo, O., Ramiadantsoa, T., Economic impacts of political instability in Madagascar.


    Teaching and outreach

    I spent a bit of my time showing how mathematics can be applied to ecology and conservation, and giving a glimpse of the life of a research to high school students in Madagascar. I also co-founded (with Cara Brook) and teach workshops (E2M2)to improve quantitative skills in Madagascar. Benjamin Rice and I are supporting (financially and academically) master's students in the STEM field until completion of the thesis. I am also creating a new peer review scientific journal called "zava-boary" (nature in Malagasy) to provide masters students an opportunity to publish their work free of charge.

    My other activites include fostering cultural exchanges between Madagascar and other countries. I am a member of two societies: the Finnish-based (Suomi-Madagascar Seura) and the Malagasy-based (Madagascar-Finland). On top of cultural exchanges, we organize fund raising to help underprivileged students in Madagascar.


    Contact & CV

    My CV
    Email: ramiadantsoa-AT-wisc.edu
    Twitter: @TRamiadantsoa