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International Journal of Zoology
Volume 2012 (2012), Article ID 149026, 9 pages
http://dx.doi.org/10.1155/2012/149026
Research Article

Identifying Large- and Small-Scale Habitat Characteristics of Monarch Butterfly Migratory Roost Sites with Citizen Science Observations

1Odum School of Ecology, The University of Georgia, Athens, GA 30602, USA
2D.B. Warnell School of Forestry and Natural Resources, The University of Georgia, Athens, GA 30602, USA
3Journey North, 1321 Bragg Hill Road, Norwich, VT 05055, USA

Received 29 January 2012; Revised 15 March 2012; Accepted 20 March 2012

Academic Editor: Anne Goodenough

Copyright © 2012 Andrew K. Davis et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Monarch butterflies (Danaus plexippus) in eastern North America must make frequent stops to rest and refuel during their annual migration. During these stopovers, monarchs form communal roosts, which are often observed by laypersons. Journey North is a citizen science program that compiles roost observations, and we examined these data in an attempt to identify habitat characteristics of roosts. From each observation we extracted information on the type of vegetation used, and we used GIS and a national landcover data set to determine land cover characteristics within a 10 km radius of the roost. Ninety-seven percent of roosts were reported on trees; most were in pines and conifers, maples, oaks, pecans and willows. Conifers and maples were used most often in northern flyway regions, while pecans and oaks were more-frequently used in southern regions. No one landcover type was directly associated with roost sites, although there was more open water near roost sites than around random sites. Roosts in southern Texas were associated primarily with grasslands, but this was not the case elsewhere. Considering the large variety of tree types used and the diversity of landcover types around roost sites, monarchs appear highly-adaptable in terms of roost site selection.