Outline of Quino Recovery Plan - The Xerces Society

Responses to carbon dioxide increases by larvae of the buckeye butterfly
(Junonia coenia, a co-occurring relative of the Quino checkerspot), feeding on
English plantain (Plantago lanceolata, a co-occurring close relative of P.
erecta), are particularly relevant. When the current atmospheric carbon dioxide
concentration was approximately doubled, recorded effects included a 36 percent
increase in larval mortality, increased development time, and decreased biomass
(Fajer 1989, 1991; Fajer et al. 1989). Growth of early instar (younger) larvae
was more reduced than that of later instars (Fajer 1989, Fajer et al. 1989).
Buckeye butterfly results are generally consistent with those of other studies
encompassing taxonomically diverse representatives of the order Lepidoptera,
suggesting similarly negative effects on Quino checkerspot populations. An
extended development time in early instar prediapause larvae would increase
probability of mortality factors prior to reproduction due to early hostplant
decline (see Climate Effects section above and Climate Change section directly
below).
8. Climate Change
Climate change is likely affecting the Quino checkerspot. A trend toward global
warming in the last century has been linked to elevated greenhouse gases (Karl
et al. 1996, IPCC 1996, Easterling et al. 1997). For Mexico and southern
California, the first warming appears to have started in the 1930's (Parmesan in
press). Despite increased El Niño event frequency and intensity (IPCC 1996),
southern California is one of the few regions apparently receiving less overall
precipitation (Karl et al. 1996). Even if more frequent El Niño events eventually
result in increased total precipitation, warmer temperatures and increased
evaporation rates could still cause habitats to be drier during the crucial late
spring months, and hostplants would decline more quickly than in the past (Field
et al. 1999).
Using historical records and recent field surveys, Parmesan (1996) compared the
distribution of Euphydryas editha in the early part of the twentieth century to
that in 1994-1996. She found the southernmost populations had the highest
apparent extinction rate (80 percent) while northernmost populations had the
lowest (less than 20 percent) Populations had apparently been extirpated in areas
where habitat patches were otherwise (at least currently) suitable. This skewed
extirpation pattern resulted in the apparent contraction of the southern boundary
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