Newsletters and Literature

Newsletters and Abstracts of Recent Articles

2021

2020

2020 Articles and Reports

  • A research project from the Transportation Research Board on "Evaluating the Suitability of Roadside Corridors for Use by Monarch Butterflies" has been released as a pre-publication of the final report here; the research products are available from this Monarch Joint Venture webpage.

  • Xerces has recently released a blog post with the results of their west-wide breeding habitat monitoring. At all but one state that has been monitored for the past 3 years, monarch breeding numbers were lower than the previous two years (note that Arizona was not included here).

"Our quasi-extinction threshold collected from the literature ranged between 20,000 and 50,000 butterflies. Across this range, the probability of quasi-extinction for the western monarch population reached 99.99% (99.98–100.0) by 50 years in both the “current” or baseline model and all future scenarios tested." (NOTE: The western monarch population was estimated at 28,429 monarchs in 2018)

"In the western population, further protecting overwintering grounds and nectar resources could cause a large and positive population response by the species. However, those changes would need to be greater in scope than what our analysis viewed as plausible."

2019 Articles and Reports

  • Xerces has recently released a blog post with the results of their west-wide breeding habitat monitoring. At all but one state that has been monitored for the past 3 years, monarch breeding numbers were lower than the previous two years (note that Arizona was not included here).

"Our quasi-extinction threshold collected from the literature ranged between 20,000 and 50,000 butterflies. Across this range, the probability of quasi-extinction for the western monarch population reached 99.99% (99.98–100.0) by 50 years in both the “current” or baseline model and all future scenarios tested." (NOTE: The western monarch population was estimated at 28,429 monarchs in 2018)

"In the western population, further protecting overwintering grounds and nectar resources could cause a large and positive population response by the species. However, those changes would need to be greater in scope than what our analysis viewed as plausible."

2018 Articles and Reports

Crone_et_al-2019-Ecological_Applications (2).pdf
  • There is a new paper discussing the decline of the western monarch: "Why are monarch butterflies declining in the West? Understanding the importance of multiple correlated drivers". Click above to view or download.