Sabine Dietz, PhD candidateWarmly dressed researcher kneeling on rugged hillside



  • BA Environmental and Resource Management, Trent University
  • Maîtrise en études de l’environnement, Université de Moncton  (Les relations formelles et informelles entre les organisations non gouvernementales en environnement (ONGEs) et les gouvernements fédéral et provincial au Nouveau-Brunswick)

My PhD research started in 2009, and is part-time (I also currently work for the NB Department of Environment managing climate change adaptation projects in the province).

“Populations at the Edge: A comparative examination of isolated marginal populations of plants in the face of environmental change”

I am interested in peripheral, isolated plant populations, their survival over time, and their viability in the face of environmental change. My particular interest is in small vascular plants, such as arctic-alpine species that occur here in New Brunswick.

Distribution patterns, which form the basis for the study of  ecology and biogeography, are generally thought to result from the interaction between species’ ranges of ecological tolerance to limiting environmental factors (essentially determined by their genotype and phenotypic plasticity), the spatial distribution of habitat features, and dispersal mechanisms. Given that forecasted climate changes will be faster than those the world has experienced in the past 10,000 years, there is concern that many species may be extirpated from parts of their current range. If the climate is expected to warm, then populations of northern species at the rear (southern) margin of their range will experience the greatest stress. Will they be able to adapt, in the long term, to changing conditions, or will they face elimination?

Peripheral populations are important components of rare plant diversity and can be considerable repositories of genetic resources and since genetic variability is essential in conservation, these populations should be protected. Whether these isolated populations at the periphery can survive in the face of environmental change depends on three factors: the availability of appropriate habitat, the ability of the species to migrate (expand or disperse), and the ability of a species to acclimate (phenotypic plasticity) to change.  

The purpose of my research is to evaluate the genetic variability and reproductive fitness traits as measures of population fitness of individuals from different populations of arctic-alpine species (Northern Bilberry, Northern White Anemone, White Mountain Avens) at the southern margin of their range in comparison to populations in the centre of their range. From this, we can make some inferences of their adaptive potential and risk of extinction in the face of environmental changes such as climatic warming. This will aid in conservation planning for these populations.