Ecological Determinants of Distribution Decline and Risk of Extinction in Moths

Abstract

For successful conservation of species it is important to identify traits that predispose species to the risk of extinction. By identifying such traits conservation efforts can be directed toward species that are most at risk of becoming threatened. We used data derived from the literature to determine ecological traits that affect distribution, distribution change, and the risk of extinction in Finnish noctuid moths (Lepidoptera, Noctuidae). The ecological traits we examined included body size, larval specificity, length of the flight period, and overwintering stage. In addition, in monophagous species we examined the effects of resource distribution. Larval specificity, length of the flight period, and the overwintering stage each had an independent effect on the risk of extinction when the effects of other traits were controlled by entering all traits into the same regression model. Not a single trait predicted the risk of extinction when analysis was conducted without controlling for the other traits. This discrepancy among the results suggests that a single trait may not be enough to allow prediction of the risk of extinction. Instead, it seems that for successful, predictive conservation science data on several ecological characteristics are needed. Determinantes Ecológicos de la Reducción en la Distribución y del Riesgo de Extinción en Mariposas NocturnasResumen: Para la conservación exitosa de especies es importante identificar características que las predispongan al riesgo de extinción. Al identificar esas características, los esfuerzos de conservación pueden dirigirse a las especies con mayor riesgo de ser amenazadas. Utilizamos datos derivados de la literatura para determinar las características ecológicas que afectan la distribución, al cambio en distribución y el riesgo de extinción en mariposas nocturnas (Lepidopetera, Noctuidae) finlandesas. Las características ecológicas que examinamos incluyeron el tamaño corporal, la especificidad larvaria, la longitud del período de vuelo y la etapa de hibernación. Adicionalmente, examinamos los efectos de la distribución de recursos en especies monófagas. La especificidad larvaria, la longitud del período de vuelo y la etapa de hibernación tuvieron un efecto independiente sobre el riesgo de extinción cuando los efectos de otras características eran controlados al incorporar todas las características al mismo modelo de regresión. Ninguna característica predijo el riesgo de extinción cuando el análisis se realizó sin controlar a las demás características. Esta discrepancia entre los resultados sugiere que una sola característica puede no ser suficiente para permitir la predicción del riesgo de extinción. En cambio, parece que se requieren datos de varias características ecológicas para una ciencia conservacionista predictiva exitosa.

Adult longevity and its relationship with conservation status in European butterflies

“…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).…”

“…Despite the fact that butterlies comprise one of the most studied invertebrate groups, such knowledge is nevertheless available for only a very limited number of butterly species (van Swaay 2002;Wenzel et al 2006;Müller et al 2010). 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).…”

“…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).…”

“…However, for efective conservation, it is necessary to properly identify species threatened with extinction, and Red Lists are compiled for this purpose. Assessments of species positions on such lists should ideally be based on thorough knowledge of their biology and ecology and how these afect the species vulnerability to threats (Margules and Pressey 2000; Mattila et al 2006). Despite the fact that butterlies comprise one of the most studied invertebrate groups, such knowledge is nevertheless available for only a very limited number of butterly species (van Swaay 2002;Wenzel et al 2006;Müller et al 2010).…”