Research update: July 2015

July was truly summer time up on the roofs – hot, muggy, sunny, buggy. I have to remind myself that all of these distracting things are the ones I miss during the cold winter months. The fact that the green roofs are pretty darn beautiful makes up for it!

My prairie plants are beautiful when they're blooming up on the green roof!

My prairie plants are beautiful when they’re blooming up on the green roof!

A native bee from the genus "Anthidium" visits my blooming prairie plants on the green roof.

A native bee from the genus “Anthidium” visits my blooming prairie plants on the green roof.

The good news is that most of the plants have enjoyed the rainy July and are still looking quite well. Some species that weren’t looking too good last year at this time now have flowers. This means that they’re reproducing (or trying to anyway) and that there is a good chance that their offspring will be around on the green roofs next year. With my experimental green roof trays, I conducted the water retention and evaporation experiment again that I’ve described in past blog posts. Conditions need to be totally dry to do this experiment and with the extra rain in Chicago this month, it was tough to schedule this in. But, with help, I just barely made measurements before it started to rain again and was able to get the data I need. I think I’ve collected enough data from this experiment this summer to make some interesting conclusions, but I’ll have to see. Maybe I’ll do it again next summer to compare the effect of the plants when they’re a year older? We’ll have to see.

A bumble bee, prairie grass and a green roof ecologist: a pretty picture on the green roof in July

A bumble bee, prairie grass and a green roof ecologist: a pretty picture on the green roof in July

For my other experiment that measures the movement of pollen between green roof populations, I continued to cover flowers in florescent dye and look for movement of the dye by pollinators. Unfortunately, after trying this experiment on 8 different days, I didn’t see any evidence that the pollinators were moving the dye. Does this mean that they’re also not moving pollen between plants on the green roofs and the ground? I’m not sure. I’ll collect seeds from these plants and use DNA-fingerprinting techniques in the lab this fall to find out more information. For now, the plants are finished flowering and have all been moved from their ground-level or roof sites to be watched until their fruits ripen and I can extract their seeds and DNA. Aside from being attacked by a colony of biting ants (over 20 of them that somehow crawled into my shirt – talk about uncomfortable!), things seem to be moving along.


2 thoughts on “Research update: July 2015

  1. How do you ensure the dye isn’t impacting the pollination through color, smell, reflectivity, absorption, etc? Not that I have an answer….just curious how we know what would impact the pollinator 🙂


    • Good question Jeff! I’ve thought about this myself. I had to use different colors of dye to mark the different populations (so I could tell the “roof” plants from the “ground” plants) and I thought, “If a bee has a search image of a white flower, why would it go to this flower that I’ve now painted red?”
      I don’t really know the answer to this but I’m looking into it. So far most of the published research suggests that pollinators will still move the dye although perhaps not as much as they would pollen. So if you measure dye movement, it will probably be an underestimate of actual pollen movement. Also, we are still learning how pollinators “see” flowers. We know that they can see certain wavelengths that we can’t – they pick up on UV cues so that flowers look like they are glowing as if under a black light. Scent chemistry also plays a role and although the dye is supposed to be unscented (and it didn’t smell like anything to me), there could be some chemicals in there that pollinators pick up on.
      Thanks so much for the comment and for your interest!

      Liked by 1 person

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