A mobility index for Canadian butterfly species based on naturalists' knowledge

Abstract

Mobility is a key component of species' biology. Research on mobility is inherently difficult, however, resulting in studies of narrow taxonomic, spatial, and temporal scope with results that are difficult to compare between studies. We had three goals for our research: (1) construct a data set of mobility estimates for the butterfly species of Canada based on naturalists' knowledge; (2) develop methods to evaluate aspects of accuracy and precision for knowledge-based ecological research such as ours; and (3) using our data set, test mobility-related hypotheses of species-level relationships. We distributed a questionnaire to amateur and professional lepidopterists in Canada and northern USA, asking them to estimate the mobility of Canadian butterfly species based on their field experience. Based on responses from 51 lepidopterists with approximately 800 years of combined field experience, we received mobility estimates for almost all (291 out of 307) of Canada's butterfly taxa. Mobility estimates were consistent among respondents and were not affected by respondent expertise. Mobility carries a strong phylogenetic signal and is positively related to wingspan (albeit weakly), range size, and host plant breadth, and negatively related to conservation risk. Reliance upon naturalists' experience was essential to the feasibility of our project, and provides a promising method for many types of ecological research. © 2011 Springer Science+Business Media B.V.