Fragmentation of habitat patches is one of many consequences that occurs due to urbanization. This fragmentation can lead to isolated populations that are completely surrounded by urban structures. This isolation can happen on relatively quick timescales, as quickly as 30 years!
Due to the loss of habitat patches available for nesting, there can be plant-pollinator deficits in the city, which then lowers plant production. On the other hand, urban gardens with diverse flowers may cause an urban pollinator enrichment, which then increases plant reproduction.
Based on these two competing hypotheses, graduate student Ruth Rivkin and colleagues tested how these hypotheses hold up on an urban to rural gradient. Using the plant Brasica rapa, which is a fast growing plant found both within and outside the city, Ruth measured reproductive success and pollen dispersal. Plants were set up in 30 sites across the Greater Toronto Area in volunteers’ gardens that spanned an urban to rural gradient.
There was no difference in mean seed set across the gradient, however, there was variation in seed set with the season. Pollen dispersal was lowest in the city, reducing gradually from rural to urban, and also varied by season. These results are consistent with the plant-pollinator deficit hypothesis.
I am interested in urban ecology and evolution. Urbanization can have drastic impacts on local ecosystems, both negative and positive, and creates a new environment for organisms to experience. To understand the impacts that urbanization plays on organisms, I look through the lense of population genetics and molecular evolution.
- Urban Observation of the Week: Golden Jackal - July 28, 2021
- Urban Observation of the Week: Bellflowers in Munich - July 21, 2021
- Urban Observation of the Week: So Many Plants - July 14, 2021