Evolution & ecology in urban environments

Approximately 50% of the human population lives in urban areas and this is projected to increase to almost 70% by 2050. As urban areas expand to accommodate the growing population, many organisms are being exposed to these novel environments. The green spaces in urban areas also represent the primary natural habitat many people will experience. Understanding the ecology and evolution of cities is key to creating lasting, thriving, green urban areas.

In addition to the projects outlined below, in 2018 I also contributed to a a review paper on the gaps in the field of urban evolutionary ecology.

Plant evolution in urban environments

Although there has been considerable work investigating the ecological consequences of urbanization, there are only a handful of studies that have determined whether urbanization influences evolutionary processes and patterns. There are even fewer studies that have been conducted on plants! I wrote a book chapter recently on life history evolution of plants in urban environments, summarizing both research thus far and opportunities for future work.

As a component of my dissertation, I wanted to determine if common ragweed has adapted in response to urban environments. Some research suggests that common ragweed flowers earlier and produces more pollen in urban compared to rural areas via phenotypic plasticity. I expanded on this research by comparing populations collected in urban and rural Minneapolis to determine whether they have adapted in response to the selection pressures present within cities.

One of my four urban field sites, with newly watered ragweed seedlings

I conducted an urban-rural reciprocal transplant experiment where I planted multiple urban and rural populations in four field sites in Minneapolis and the surrounding rural area and measured patterns of phenotypic divergence and selection. I found that urban populations flowered earlier than rural populations and evidence for inter-population differences in flowering time among urban populations. This work was published in the Proceedings of the Royal Society B as part of a special issue on ‘The evolution of city life”. Read it here!

City Backyard Science – Community driven conservation science

In 2019, I co-led a community driven conservation initiative in Minneapolis with John Benning. ‘City Backyard Science‘ is a community science project with three goals:

  1. Conservation: How do we increase urban greening and biodiversity?
  2. Community engagement: How can we connect communities with science and the natural world?
  3. Urban evolutionary ecology: How do urban bee communities differ from rural communities? Are native plants adapted to urban environments?

In the Spring, we set up raised beds on the boulevard in front of family homes, and used these “plots” as an experiment across multiple neighborhoods in Minneapolis. We planted each raised bed with a set of native plants.

One of the raised beds: Black-Eyed Susan and Prairie Phlox are flowering

All the households had children ages 5-12 because we were interested in exposing children to the joys of the natural world and getting them excited about doing science in their backyard. We trained families on simple plant and pollinator data collection and sent them small, guided activities. The purpose of these were twofold: to teach the scientific method and to provide nature based activities.

Example activity pack sent to families. See here for similar resources.

We will use these data to answer about about urban pollinator habitat preferences and plant adaptation to urban environments. At the end of the season, we also hosted a community event at the Bell Natural History Museum for the participating families. We hosted some additional plant related activities, and helped the families graph their data to see what patterns they could see!

Community collected data on flowering of Black-Eyed Susan,
Prairie Phlox and Partridge Pea

We started this project with funding from from the University of Minnesota Institute on the Environment. We are always looking for additional funding to expand the program in future years.