Elizaveta Litvak

Hello! I am a postdoctoral fellow at Urban Ecology Research Lab, University of Utah. I earned PhD and MS in Earth System Science at the University of California, Irvine and MS (equivalent) in Physics at Moscow State University (Russia).

Urban environments are places where more than 50% of the world population lives. However – ironically – urban environments are not well understood, and we are yet to find out all the factors and mechanisms that shape urban climates, ecology and hydrology.

People highly value live plants in the cities and perceive many benefits from them (such as consumption of carbon dioxide, oxygen production, shading from sunlight, aesthetic etc.). However, urban plants need care and keeping them in cities often implies substantial costs. In arid regions, where water issues are especially pressing, sustaining urban plants takes large (yet very roughly estimated) fractions of municipal water budgets. In order to improve water efficiency of urban landscapes, we need to understand how urban plants function and how much water they use. At this point, you probably wonder why on earth this is not known yet. Okay, let me outline the major challenges here using the urban forest in Los Angeles I currently focus on as an example.

  • First of all, there is a very large number of species planted and irrigated by people – anything that people enjoy and are able to sustain –  as a result, the diversity greatly exceeds natural ecosystems
  • The conditions and treatments experienced by plants are very unusual and sometimes extreme compared to natural habitats
  • Urban areas have "mosaic" structure, with plants appearing here and there (unlike forests or grasslands), making it hard to account for them all and also placing each one into different conditions.

Here is what I use to overcome these challenges:

  • Detailed datasets of measurements made on living urban trees (all non-destructive!),
  • Analyses of how environmental conditions and physiological mechanisms influence water use of trees
  • Fine-resolution satellite images that distinguish every tree in the landscape.

In addition to asking “how much water do plants use?” we, of course, want to understand why they use that much, so I actually ask many more questions… and the story becomes more interesting… What are seasonal and spatial patterns of water use and why? How large are the differences between and within species and what drives them? What is the role of water transport mechanisms inside the plants (and how does it work in the first place)? And, finally: how to predict water use of individual plants and landscapes and how to lower water use without giving up beautiful green spaces?

This research project contributes to better understanding of plant water relations in general and urban ecohydrology in particular. It also provides useful information for developing more water-wise urban landscapes.