Threat status in butterflies and its ecological correlates: how far can we generalize?

Abstract

It would be very useful for conservation biologists to be able to predict threat status from ecological characteristics of species, and past studies have shown promising results. Regarding one important threat indicator taxon, the butterflies, results from a study on Finnish species by Kotiaho et al. (Proc Natl Acad Sci USA 102:1963-1967, suggested that threatened butterflies on average have narrower niches, more restricted distributions of the larval host plants, poorer dispersal abilities and shorter flight periods. However, this study did not control for phylogenetic relatedness of species. To examine the effects of phylogenetic control, and to see how far it is possible to generalize from specific investigations, we compared the ecological characteristics of threatened and non-threatened butterfly species at two different geographical scales: Sweden and Europe. Our results illustrate the difficulties of generalizing between sites, geographical scales, scoring methods, and phylogenetic versus non-phylogenetic analyses. Controlling for phylogeny is shown to be essential. The most robust result is that threatened species have narrower habitat ranges at the local scale.

Adult longevity and its relationship with conservation status in European butterflies

“…In particular, an underrepresented group are the species from Mediterranean region as well as from northern Europe, the conservation status of which is potentially less related to adult longevity and more to the life history parameters beyond the scope of the present study, such as wintering stage and voltinism (Mattila et al 2006;Nylin and Bergström 2009). Another limitation of our database is the fact that it lacked very common species, mostly of Nymphalidae and Pieridae families, which are neglected in mark-recapture studies, apparently because of the lack of scientiic and conservation interest in them.…”

“…Therefore, for their successful conservation, it is important to identify traits that predispose butterly species to extinction risk (Mattila et al 2006). Life history traits and/or ecological characteristics could be used as indicators of potential vulnerability to threats as many of these characteristics are common among species of conservation concern (Statzner et al 2001;Mattila et al 2006;Nylin and Bergström 2009).…”

“…Such a situation leads Studies conducted to date have identiied a wide range of butterly characteristics that can potentially act as proxies for extinction risk. One of the most commonly addressed aspects in this respect is the division into generalists and specialists (Nylin and Bergström 2009;Ali and Agrawal 2012;Bartoňová et al 2014). The latter group includes a disproportionally high number of threatened species due to their stricter habitat and host plant requirements (Hodgson 1993;Purvis et al 2000;Fontaine et al 2007).…”

“…The latter group includes a disproportionally high number of threatened species due to their stricter habitat and host plant requirements (Hodgson 1993;Purvis et al 2000;Fontaine et al 2007). Another well-established pattern relates to life history and voltinism, where univoltine species and/or those overwintering in the egg or larval stage are more susceptible to climate change, which has recently become one of the most serious drivers of butterly declines (Hodgson 1993;Conrad et al 2004;Mattila et al 2006;Nylin and Bergström 2009). In addition, low mobility was typically reported for threatened butterlies (Kotiaho et al 2005;Mattila et al 2006;Nylin and Bergström 2009;Habel et al 2015).…”

“…Another well-established pattern relates to life history and voltinism, where univoltine species and/or those overwintering in the egg or larval stage are more susceptible to climate change, which has recently become one of the most serious drivers of butterly declines (Hodgson 1993;Conrad et al 2004;Mattila et al 2006;Nylin and Bergström 2009). In addition, low mobility was typically reported for threatened butterlies (Kotiaho et al 2005;Mattila et al 2006;Nylin and Bergström 2009;Habel et al 2015). This is not surprising, because less mobile species with low colonization success rates are more vulnerable to the efects of habitat fragmentation, which is nowadays a crucial threat for butterlies (Thomas 1995;Novacek and Cleland 2001;Baguette and Schtickzelle 2006;Franzen and;Johannesson 2007).…”