Endangered Butterfly Threatened by Invasive Species

[Cirsium]

Sometimes the harm caused by invasive species is not readily apparent. The butterflies are there, the host plants are there, but ...

... Dominance of natural shortgrass prairies by tall stature grasses like A. elatius may be an insidious form of habitat degradation for grassland Lepidoptera worldwide, but it may go largely unnoticed because larval and adult resources can persist under the unnaturally tall grass canopy. ...

http://www.springerlink.com/content/283kq5211r852783/fulltext.pdf

[Gloria]

Wow, what an interesting read.
So the taller grasses were obscuring the lupine host plants from the butterflies.
Plus the areas closer to the ground where ambient temperatures are generally higher and there is protection from wind (that cools wings when butterflies are thermoregulating for egg laying and or flight) were too shaded by the taller grasses to allow the gathering of incident light by wing surfaces. Thus less egg laying and even less landing in the area because regaining flight would be hindered.

This showed that overall sward height was important to host apparency and basking habitat for this butterfly and maybe others.

The weather component was also intriguing. Early warm weather in spring by just a couple of weeks could allow the butterflies to lay eggs before the invasive grass could begin to flower and increase height. Cool late spring weather reduced populations of the butterfly greatly as the ovipositing events were delayed enough for the grasses to obscure the host plant and basking habitat.

I really enjoyed reading this information. Thanks for sharing your find with us,Cirsium!!!

[Hedgerowe]

Darn! Could not open the link; am looking forward to reading it from home this evening.

[NEWisc]

Really enjoyed the article. It was very interesting to see how all of the different factors related to each other, and how they each affected the butterflies.

It's a great example of how we can easily overlook the detrimental impact of invasive species. And how important it is to maintain natural communities as close as possible to their natural state.