Title

Data from: Monarch butterfly and milkweed declines substantially predate the use of genetically modified crops

Document Type

Data

DOI

10.5061/dryad.sk37gd2

Publication Date

1-1-2019

Description

Monarch butterfly (Danaus plexippus) decline over the past 25 years has received considerable public and scientific attention, in large part because its decline, and that of its milkweed (Asclepias spp.) host plant, have been linked to genetically modified (GM) crops and associated herbicide use. Here, we use museum and herbaria specimens to extend our knowledge of the dynamics of both monarchs and milkweeds in the United States to more than a century, from 1900 to 2016. We show that both monarchs and milkweeds increased during the early 20th century and that recent declines are actually part of a much longer-term decline in both monarchs and milkweed beginning around 1950. Herbicide-resistant crops, therefore, are clearly not the only culprit and, likely, not even the primary culprit: Not only did monarch and milkweed declines begin decades before GM crops were introduced, but other variables, particularly a decline in the number of farms, predict common milkweed trends more strongly over the period studied here.,Raw_recordsThis archive contains: 1) Raw specimen records from the University of Wisconsin, the Consortium of Midwest Herbaria, and Symbiota. 2) Redacted specimen records from the University of Minnesota (see PART 0.0 in the R_scripts archive for more information). 3) The DOI for the raw specimen records from GBIF.R_scriptsThis archive contains the R scripts used for all data analyses.,

Publisher

DRYAD

Source Link

http://datadryad.org/stash/dataset/doi:10.5061/dryad.sk37gd2

Version

1

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