02153nas a2200193 4500008004100000245011400041210006900155300001400224490000800238520152700246100001501773700001401788700001401802700002101816700001501837700001601852700002001868856007101888 2018 eng d00aLong- and short-term responses of Asclepias species differ in respect to fire, grazing, and nutrient addition0 aLong and shortterm responses of Asclepias species differ in resp a2008-20170 v1053 a

PREMISE OF THE STUDY: The tallgrass prairie ecosystem has experienced a dramatic reduction over the past 150 yr. This reduction has impacted the abundance of native grassland species, including milkweeds (Asclepias).


METHODS: We used two long-term (27 yr) data sets to examine how fire, grazing, and nutrient addition shape milkweed abundance in tallgrass prairie. We compared these results to those of a greenhouse experiment that varied nutrient levels in the absence of competition, herbivory, and mutualistic relationships.


KEY RESULTS: Asclepias species exhibited broad patterns in response to burning regimes that did not include grazing, but experienced more species-specific patterns in other combinations. Asclepias syriaca was the only species to increase in abundance in plots that included burning and nutrient addition. In the greenhouse we found that nitrogen significantly increased biomass, while no effect of phosphorus was detected.


CONCLUSIONS: These results indicate that A. syriaca will do best in settings with high nutrient loads, low competition, and no grazers. These characteristics define a small portion of the tallgrass prairie but exemplify modern agricultural settings, which have replaced prairies. However, other milkweeds examined did not share this pattern, which indicates that milkweed species will respond differently when exposed to agricultural settings, with some less able to cope with land conversion to pasture or row-crop agriculture.

1 aRicono, A.1 aDixon, R.1 aEaton, I.1 aBrightbill, C.M.1 aYaziji, Y.1 aPuzey, J.R.1 aDalgleish, H.J. uhttps://bsapubs.onlinelibrary.wiley.com/doi/full/10.1002/ajb2.1197