Spatially Explicit Evolution of Diversity (SPEED)

Background

The species environmental niche consists of the biotic and abiotic conditions necessary for long-term persistence.  As such, the niche concept occupies a central place in the development of ecological theories of competition, limiting ecological similarity, and species distribution.  To be present in the same community, species need to have niches that overlap in some way.  Species also need to have niche differences that reduce competition to a point that member species are not eventually excluded.  The niche is also important in determining how species respond to ongoing climate change.  Species with narrow environmental requirements (narrow niches) may occur in the few geographic locations that offer acceptable conditions.  When these species have limited capacity for dispersal, and/or have been isolated by urbanization, agriculture or other barriers to dispersal, climate change may force upon species the alternatives of rapid adaptation (via response to natural selection) or extinction. We focus on species in the grass-like family Restionaceae, largely endemic to South Africa.

The Goals

We seek to understand how the species niche has evolved and how the capacity for niche change might impact future patterns of species diversity in the face of ongoing climate change.  Gaining an understanding of these niche dynamics entails understanding how species niches differ currently and how these differences evolved.  We need to understand how rates of evolution in groups of related species change in time. To understand how changes in the composition of regional species pools translates into changes in biodiversity, we need to understand how ecological similarities among species, represented by species evolutionary relationships, influence the composition of ecological communities.

The Approach

We combine the approaches of evolutionary theory and molecular systematics, on the one hand, and ecology on the other. The approach is interdisciplinary in that activities in these areas produce results that are used to support subsequent activities in other disciplines.  Notably, DNA sequence data provide the raw material for developing hypotheses of evolutionary relationships.  Data on species occurrences and climate allow us to model the environmental niche of species.  From these models, we estimate characteristics of species niches.  We combine information on evolutionary relationships, ecological characteristics, and species composition in communities to determine how evolutionary relationships influence the assembly of communities.

Significance of the Project

This project is significant because it develops a framework for evaluating the degree to which rapid evolution may contribute to species responses to climate change.  With this framework it will be possible to evaluate the potential for evolutionary response to climate change in large groups, potentially hundreds, of related species.  By combining ecological data, understanding of evolutionary relationships and rates, and projections of future climates, we should be able to develop more informed projections of the impacts of ongoing climate change.  

Further information

• Peter B. Pearman
  

• Niklaus Zimmermann
  

• Nicolas Salamin lab