Parallel Evolutionary radiations in Protea and Pelargonium in the Greater Cape Floristic Region

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Contents

Overview

Protea punctata in the Swartberg. Photo by Jane Carlson
Current approaches to predicting changes in community structure and function are based largely on static assessments. They fail to consider relationships between species' attributes that affect their function in a given environment (functional traits), genetic variation underlying those functional traits, and the dynamics of the communities of which they are part. Each of these relationships reflects the unique evolutionary history of the lineage in question, and lineages that have flourished through dramatic historical climate change are likely to harbor significant information about functional trait evolution that will shed new light on adaptation and evolutionary potential. We focus on Protea and Pelargonium, two South African plant genera that have undergone dramatic diversification since the Miocene during long-term aridification and dramatic shifts in climate. Southern Africa has higher plant diversity than most tropical regions, yet much of this diversity stems from radiations in just 30 major lineages, including Protea and Pelargonium. These genera span two biodiversity hot spots, the fynbos and succulent karoo biomes in the Greater Cape Floristic Region (GFCR). Our overall goal is to develop an understanding of functional trait variation in both genetic and evolutionary contexts in Protea and Pelargonium. This will allow us to predict the characteristics of communities in which they occur and the resilience of those communities to climate change. To achieve these goals, we will answer three sets of hierarchically nested questions:

  1. How do functional traits vary within and between species? How are differences related to environmental variation (e.g., climate, soils, and fire)? What is the genetic basis of these differences?
  2. What are the phylogenetic histories of functional trait change? How are the rates of trait evolution related to changes in niche parameters?
  3. How are taxonomic and trait level diversity and abundance of focal taxa interrelated with community composition along environmental gradients? How are these patterns related to ecosystem resilience to fire?

To answer these questions, we will assess functional traits on nearly all species of Protea and Pelargonium found in the GFCR; for a subset of species we will examine detailed relationships between

Interactive overview

We have an interactive mind map that provides an overview of the project. We'll be updating and revising it as the project proceeds. functional traits, photosynthesis, water use efficiency and leaf life span. We will identify the genetic basis of trait variation both through geographically extensive sampling within widely distributed species and through intensive population sampling in two hybrid species complexes using state-of-the-art nextgeneration sequencing technology to map variation in several thousand individual genomes. Functional trait evolution and its association with environmental variation will be assessed using highly resolved evolutionary histories inferred from high-coverage transcriptome sequences we will generate for nearly all species in both genera. We will evaluate rates of diversification of traits and parameters of species' niches. Because trait evolution is best understood when viewed in the context of the community in which it evolved, we will also characterize the functional trait and taxonomic diversity of communities containing Protea and Pelargonium and use this information to infer community structure along environmental gradients. Ultimately, we will examine effects of taxonomic and trait diversity on ecosystem resilience in response to fire cycle interval, which strongly affects species and functional composition of communities in the region and which our ongoing research has found to by highly sensitive to projected climate changes.

  • Mind map notes from our January, 2013 project meeting in Davis, CA

People

University of Connecticut

Australian National University

University of California - Davis

Collaborators

  • Freek Bakker (University of Wageningen)
  • Jane Carlson (Nicholls State University; post-doctoral research associate at University of Connecticut: 2011-2012)
  • Tony Rebelo (South African National Biodiversity Institute)
  • Jasper Slingsby (South African Ecological Observatory Network)
  • Elizabeth Marais (University of Stellenbosch)

Alumni

  • Hugo Martinez-Cabrera (post-doctoral research associate at University of Connecticut: 2011)
  • Nina Noah (technician at University of Chicago: 2011)
  • Adam Wilson (graduate student at University of Connecticut: 2011)

Publications

  • Martínez-Cabrera, H. I., C. D. Schlichting, J. A. Silander, and C. S. Jones. 2012. Low levels of climate niche conservatism may explain clade diversity patterns in the South African genus Pelargonium (Geraniaceae) American Journal of Botany 99:954-960. doi:10.3732/ajb.1100600.
  • Carlson, J. E., and K. E. Holsinger. 2012. Developmental plasticity in Protea as an evolutionary response to environmental clines in the Cape Floristic Region. PLoS One 7(12):e52035. doi:10.1371/journal.pone.0052035
  • Carlson, J. E., and K. E. Holsinger. 2013. Direct and indirect selection on floral pigmentation by pollinators and seed predators in a color polymorphic South African shrub. Oecologia 171:905-919. doi:10.1007/s00442-012-2453-2
  • Jones, C. S., H. I. Martinez-Cabrera, A. B. Nicotra, K. Mocko, E. M. Marais, and C. D. Schlichting. 2013. Phylogenetic influences on leaf trait integration in Pelargonium (Geraniaceae): Convergence, divergence, and historical adaptation to a rapidly changing climate. American Journal of Botany 100:1229-1233. doi:10.3732/ajb.1200526
  • Martínez-Cabrera, H. I. and P. R. Peres-Neto. 2013. Shifts in climate foster exceptional opportunities for species radiation: the case of South African geraniums. PLoS ONE 8(12):e83087. doi: 10.1371/journal.pone.0083087
  • Wilson, A. M. and J. A. Silander, Jr. 2013. Estimating uncertainty in daily weather interpolations: a Bayesian framework for developing climate surfaces. International Journal of Climatology doi: 10.1002/joc.3859
  • Merow, C., M.J. Smith, and J. A. Silander, Jr. 2013. A practical guide to MaxEnt for modeling species’ distributions: what it does, and why inputs and settings matter. Ecography. 36:1058. 10.1111/j.1600-0587.2013.07872.x
  • Merow, C., J. Dahlgren, C.J.E. Metcalf, D. Childs, M.E.K. Evans, E. Jongejans, S. Record, M. Rees, R. Salguero-Gómez, and S. M. McMahon. 2013. Advancing population ecology with integral projection models: a practical guide. Methods in Ecology and Evolution 10.1111/2041-210X.12146
  • Merow, C., and J. A. Silander, Jr. 2013. A comparison of Maxlike and Maxent for modeling species distributions. Methods in Ecology and Evolution 10.1111/2041-210X.12152

Protocols

Data and software

As data and software become available from the project, we will provide links here.

Other resources

Information from NSF about the Dimensions of Biodiversity program

  • Synopsis for the program [1]
  • Program announcement [2]

News releases and other publicity

  • News release announcing the first awards [3]
  • A news release from LiveScience [4]
  • Dimensions of Biodiversity: Fiscal Year 2010 Projects (PDF)
  • Tracking traits from East to West: Do plant traits hold the key to understanding climate change in the Cape? [5]

Proposal to the National Science Foundation

  • Project Summary (PDF)
  • Full text of the proposal (PDF)

Photographs

Blogs and Twitter

Related projects


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