POSTDOCTORAL OPPORTUNITY: POPULATION DYNAMICS OF TROPICAL PLANTS

POSTDOCTORAL OPPORTUNITY: TROPICAL PLANT DEMOGRAPHY: The Bruna Lab at the University of Florida (www.BrunaLab.org) seeks a postdoctoral researcher to join a collaborative, NSF-funded project to evaluate the effects of drought and habitat fragmentation on the demography and population dynamics of tropical plants.

LOCATION: University of Florida, Gainesville, Florida. We will consider remote working arrangements for exceptional candidates that need to be based in a different location for part or all of their appointment. If you are interested in the position, please apply. The need to work remotely will not disqualify applicants from consideration.

SALARY: Starting salary approximately $48,000, with a competitive benefits package.

DURATION: The initial appointment will be for one year, with the possibility of renewal for a second year pending satisfactory performance.

START DATE: Flexible, but preferably by June 1, 2020.

RESPONSIBILITIES: The successful candidate will use long-term data on precipitation and plant demography collected in an experimentally fragmented landscape in Brazilian Amazon to: (1) quantify drought frequency and severity, (2) apply spline methods and other statistical techniques to disentangle the effects of drought and forest fragmentation on demographic vital rates, and (3) model how alternative drought scenarios predicted for Amazonia will influence the dynamics and viability of plant populations. The focal species for this study is Heliconia acuminata (Heliconiaceae), an understory herb for which we have long-term demographic surveys of >7000 individuals and daily precipitation at multiple locations across the study landscape, as well as data on canopy cover, soil properties, the abundance and movement of seed dispersers, etc. The successful candidate will also have the opportunity to develop and pursue novel projects in collaboration with the PIs that use these or other demographic datasets; the position includes funding for visits to collaborate with members of Dr. Maria Uriarte’s group at Columbia University and visit the field sites in Brazil (the Biological Dynamics of Forest Fragments Project).

Qualifications:

  • A PhD in ecology, statistics, or applied mathematics completed by the position start date.
  • Experience with the construction, parameterization, and analysis of structured population models (e.g., integral projection models, matrix models).
  • Strong statistical and quantitative skills
  • Programming experience (R, Python, or MATLAB).
  • A demonstrated track record of written and oral communication
  • The ability to work independently; a strong work ethic
  • A commitment to reproducible and open science.
  • Desired (but not required) skills include experience with generalized linear mixed models, stochastic population models, and the use of climate data in ecological analyses.
  • We are committed to creating an equitable and inclusive environment that promotes diversity in fields of ecology and conservation biology. We particularly welcome applicants who can contribute to this environment through their scholarship, experience, and contributions to the broader community.

To apply: Please apply by submitting the following items to http://apply.interfolio.com/75299: (1) a cover letter summarizing your research interests and relevant experience, (2) a Curriculum Vitae, and (3) contact information for three references.

Questions: Emilio M. Bruna (embruna@ufl.edu).

Last day to apply: The position will remain open until filled. Review of applications will begin on April 15, 2020.

 


Project Overview

Habitat fragmentation and drought are major threats to biodiversity, and it has been hypothesized that they could act synergistically to further reduce population viability in fragmented landscapes, particularly in the tropics. To date, however, this hypothesis remains untested for three primary reasons. First, most studies elucidating how tropical plants respond to fragmentation have studied either juvenile (i.e., seed, seedling) or larger, reproductive plants. Second, there is a growing literature on how tropical plants respond to severe droughts, but few studies have compared the responses of plants in continuous forest with those in fragments. Finally, the long-term data needed to test population-level hypotheses about climate change-fragmentation synergies are scant, especially for tropical systems. However, without multi-decadal sampling one cannot capture enough droughts to quantify their ecological impact, nor the variation in vital rates needed to parameterize demographic models of long-lived species in changing climates. Long-term data are also needed because while some demographic effects of fragmentation or drought on can be detected immediately, others may take years to manifest.

Since 1997 the PIs have been conducting annual demographic censuses of populations of the understory herb Heliconia acuminata in an experimentally fragmented landscape in the central Amazon (the Biological Dynamics of Forest Fragments Project, located outside Manaus, Brazil). They are proposing to use this dataset, coupled with the results of prior experiments and climatic data, to provide the first robust test of the hypothesis that plant population viability in fragmented landscapes decreases with increased drought frequency and intensity. They will do so by answering these three questions (1) Do drought events decrease post-seedling plant growth and survivorship, how is this influenced by plant size and demographic history, and are these effects exacerbated in fragments relative to continuous forest? (2) How do forest fragmentation and drought interact to influence plant reproduction, seedling establishment, and seedling survivorship? (3) Do the observed changes in vital rates interact to increase the probability of extinction in fragments relative to that in continuous forest?

Climate-Land Use interactions are posited as driver of extinctions, but few studies have evaluated how they interact to influence population dynamics. This is particularly true in the tropics, in part because the long-term datasets needed to do so are rare. This project will overcome this data limitation to address a key question at the nexus of population dynamics, climate change, and conservation biology. Data will be permanently archived, and so available for use by the ecological community to advance diverse areas of research. Finally, it will advance our understanding of how a large but understudied group of plants responds to global change.

Some publications providing background information on the Heliconia acuminata system   

  1. Brooks, M., K. Kristensen, M. R. Darrigo, P. Rubim, M. Uriarte, E. M. Bruna, B. Bolker. 2019.  Statistical modeling of patterns in annual reproductive rates. Ecology 1007): e02706 [pdf].
  2. Uriarte, M. Anciães, M. T.B. da Silva, P. Rubim, E. Johnson, and E. M. Bruna. 2011. Disentangling the drivers of of reduced long-distance seed dispersal by birds in an experimentally fragmented landscape. Ecology 92(4): 924-937. [pdf].
  3. Gagnon, P. R., E. M. Bruna, P. Rubim, M. R. Darrigo, R. C. Littlel, M. Uriarte, and W. J. Kress. 2011. The growth of an understory herb is chronically reduced in Amazonian forest fragments. Biological Conservation 144: 830-835.
  4. Uriarte, M., E. M. Bruna, P. Rubim, M. Anciaes, and I. Jonckeeere. 2010. Effects of forest fragmentation on seedling recruitment of an understory herb: assessing seed vs. safe-site limitation. Ecology 91(5):1317-1328. [pdf]
  5. Bruna, E. M. and M. K. Oli. 2005. Demographic consequences of habitat fragmentation for an Amazonian understory plant: analysis of life-table response experiments. Ecology 86(7): 1816-1824. [pdf]
  6. Bruna, E. M. and M. B. Nogueira-Ribeiro. 2005. Regeneration and population structure of Heliconia acuminata in Amazonian secondary forests with contrasting land-use histories. Journal of Tropical Ecology 21:127-131. [pdf]
  7. Bruna, E. M., W. J. Kress, F. Marques, and O. F. da Silva. 2004. Heliconia acuminata reproductive success is independent of local floral density. Acta Amazonica 34(3): 467-471 (cover article). [pdf]
  8. Bruna, E. M. 2003. Are plant populations in fragmented habitats recruitment limited? Tests with an Amazonian herb. Ecology, 84(4): 932-947. [pdf].
  9. Bruna, E. M., O. Nardy, S. Y. Strauss, and S. P. Harrison. 2002. Experimental assessment of Heliconia acuminata growth in a fragmented Amazonian landscape. Journal of Ecology, 90(4): 639-649. [pdf].
  10. Bruna, E. M. 2002. Effects of forest fragmentation on Heliconia acuminata seedling recruitment in the central Amazon. Oecologia, 132:235-243. [pdf].
  11. Bruna, E. M. and W. J. Kress. 2002. Habitat fragmentation and the demographic structure of an Amazonian understory herb (Heliconia acuminata). Conservation Biology 16 (5): 1256-1266.
  12. Bruna, E. M. 1999. Seeds in rainforest fragments. Nature, 402:13. [pdf]

Publications relevant to the proposed modeling and analytical methods

  • Ellner, SP, DZ Childs & M Rees. 2016. Data-driven modelling of structured populations. A practical guide to the Integral Projection Model. Cham: Springer.
  • Rees, M & SP Ellner. 2009. Integral projection models for populations in temporally varying environments. Ecological Monographs, 79:575-594.
  • Metcalf, CJE, SP Ellner, DZ Childs, R Salguero-Gomez, C Merow, SM McMahon, E Jongejans & M Rees. 2015. Statistical modelling of annual variation for inference on stochastic population dynamics using Integral Projection Models. Methods in Ecology and Evolution, 6:1007-1017.
  • Teller, BJ, PB Adler, CB Edwards, G Hooker & SP Ellner. 2016. Linking demography with drivers: climate and competition. Methods in Ecology and Evolution, 7:171-183.
  • van de Pol, M, LD Bailey, N McLean, L Rijsdijk, CR Lawson & L Brouwer. 2016. Identifying the best climatic predictors in ecology and evolution. Methods in Ecology and Evolution, 7:1246-1257.
  • Williams, JL, H Jacquemyn, BM Ochocki, R Brys & TEX Miller. 2015. Life-history evolution under climate change and its influence on the population dynamics of a long-lived plant. Journal of Ecology, 103:798-808.
  • Dalgleish, HJ, DN Koons, MB Hooten, CA Moffet & PB Adler. 2011. Climate influences the demography of three dominant sagebrush steppe plants. Ecology, 92:75-85.