Response to Davis: choosing relevant evidence to assess monarch population trends

  title={Response to Davis: choosing relevant evidence to assess monarch population trends},
  author={Lincoln Pierson Brower and Orley R. Taylor and Ernest H. Jr. Williams},
  journal={Insect Conservation and Diversity},
Abstract.  1. We recently reported in this journal that the abundance of the migratory population of monarch butterflies is declining ( Brower et al., 2011 ). Davis ( Davis, 2011 ) subsequently challenged our conclusion. 

Linking the continental migratory cycle of the monarch butterfly to understand its population decline

Threats to several of the world's great animal migrations necessitate a research agenda focused on identifying drivers of their population dynamics. The monarch butterfly is an iconic species whose

Conclusion of No Decline in Summer Monarch Population Not Supported

Three studies that concluded there had been no decline over the past two decades in summer breeding numbers for the eastern North American population are addressed and it is shown that the purported conclusion of no decline is not supported.

Potential threats to the conservation of eastern North American monarch butterflies (Danaus plexippus) and a tool for population recovery

A. A. E. W. was provided funding from a Natural Sciences and Engineering Research Council (NSERC) Alexander Graham Bell Canada Graduate Scholarship (CGS D) and an Ontario Graduate Scholarship. The

Restoring monarch butterfly habitat in the Midwestern US: ‘all hands on deck’

The eastern migratory population of monarch butterflies (Danaus plexippus plexippus) has declined by >80% within the last two decades. One possible cause of this decline is the loss of ≥1.3 billion

Advances in understanding the long-term population decline of monarch butterflies

  • A. Agrawal
  • Environmental Science
    Proceedings of the National Academy of Sciences
  • 2019
Two new studies published in PNAS add fresh analyses, considerably new data, and novel approaches to tackle the monarch mystery, as concerns about monarch conservation have been voiced at least since 1977.

A Review of Published and Unpublished Findings from 20 Long-term Monitoring Studies of Eastern Monarch Butterflies: the Population was Never in Danger, Despite Recent Winter Colony Declines

There are a large number of wildlife and insect species that are in trouble on this planet, and most believe that monarch butterflies in eastern North America are too, because of the well-publicized

Milkweed loss in agricultural fields because of herbicide use: effect on the monarch butterfly population

There has been a large decline in milkweed in agricultural fields in the Midwest over the last decade, coincident with the increased use of glyphosate herbicide in conjunction with increased planting of genetically modified (GM) glyphosate‐tolerant corn (maize) and soybeans (soya).

Local and cross‐seasonal associations of climate and land use with abundance of monarch butterflies Danaus plexippus

Quantifying how climate and land use factors drive population dynamics at regional scales is complex because it depends on the extent of spatial and temporal synchrony among local populations, and

Science‐Policy‐Practice Interfaces: Emergent knowledge and monarch butterfly conservation

We study how knowledge is produced at the intersection of science, environmental policy and public engagement. Based on analysis of monarch butterfly conservation, we critically evaluate models of

Narrating the Monarch Butterfly: Managing Knowledge Complexity and Uncertainty in Coproduction of a Collective Narrative and Public Discourse

In January 2014, the monarch butterfly reached North American political agendas due to reports of a long-term population decline. Requests were made for reliable descriptions of what was known about



Decline of monarch butterflies overwintering in Mexico: is the migratory phenomenon at risk?

Abstract.  1. During the 2009–2010 overwintering season and following a 15‐year downward trend, the total area in Mexico occupied by the eastern North American population of overwintering monarch

Are migratory monarchs really declining in eastern North America? Examining evidence from two fall census programs

Abstract.  1. The status of the eastern North American monarch butterfly population is a highly sensitive issue, given that winter and breeding habitats are being lost at an alarming rate each year,


Prior tagging studies at Atlantic coastal sites in New Jersey and Virginia suggested that fall migrant monarch butterflies (Danaus plexippus L., Nymphalidae: Danainae) of the eastern North American

Spring recolonization rate of monarch butterflies in eastern North America: New estimates from citizen-science data

It is concluded that the spring migration of monarch butterflies in eastern North America progresses faster than previously estimated, and the temporal patterns observed each year are remarkably constant.

Temporal and spatial overlap between monarch larvae and corn pollen

It is found that monarchs use milkweed in cornfields throughout their breeding season, and that per plant densities are as high or higher in agricultural habitats as in nonagricultural habitats, suggesting that agricultural practices such as weed control and foliar insecticide use could have large impacts on monarch populations.

Natal origins of migratory monarch butterflies at wintering colonies in Mexico: new isotopic evidence.

  • L. WassenaarA. Hobson
  • Environmental Science
    Proceedings of the National Academy of Sciences of the United States of America
  • 1998
Stable-hydrogen and carbon isotopic values of 597 wintering monarchs from 13 wintering roost sites were compared with isotopic patterns measured in individuals at natal sites across their breeding range over a single migration cycle, determining that all monarch wintering colonies were composed of individuals originating mainly from the Midwest, United States, thereby providing evidence for a panmictic model of wintering colony composition.

Catastrophic Winter Storm Mortality of Monarch Butterflies in Mexico during January 2002

estimated that more than 80% of the monarchs had been killed. Heavy mortality had also occurred in the Sierra Chincua and Sierra Campanario colonies (C. Gottfried and Rosario guides, pers. comm.). We

Adoption of genetically engineered crops in the U

  • Economic Research Service