Anthropogenic Fire and the Quino Butterfly
By Dr. Greg Brenner, consulting entomologist
Regarding a recent news article concerning Quino butterflies [here],
The Quino checkerspot butterfly (Euphydryas editha quino) is part of the Euphydryas editha species complex that has diverged phenotypically into geographical set of populations, each recognized as a separate subspecies among Lepidopterists. Subspecies are erected because, to the trained eye, there are consistent differences between populations. The differences are often difficult to distinguish, and at times appear to be imaginary. However, whether or not subspecies should be designated as endangered when the species complex occurs over a larger area and is surviving quite well is discussion for another post.
Conservation of the Quino checkerspot and its sister species will depend largely on the continued existence of their larval host plants. These butterflies inhabit openings within or in the vicinity of shrublands, grasslands, meadows, and lake margins. Their presence is closely tied to their larval host plant, dwarf plantain (Plantago erecta) that inhabits chaparral, coastal sage scrub and valley grassland plant communities. These plant communities are fire-adapted vegetation types and many of their component species require fire to regenerate new growth or allow seeds to germinate.
Fires in chaparral often result in a mosaic of various-aged habitats, with different plant species dominating the landscape over time as post-fire vegetation dynamics occur. Very recently burned areas of chaparral may be devoid of any surface vegetation, but these areas typically support resprouting shrubs, as well as species that principally reseed only after a fire, and particularly if adequate rainfall occurs.
In areas where fires do not occur over a long period of time, the structures of these communities typically become tall and dense, with relatively few species compared to the period immediately after a fire. This leads to a reduced number of ecological niches in unburned areas, and the less diverse habitat supports a less diverse range of wildlife species. Fires open up habitats, and thus support a greater diversity of wildlife in a given area.
Studies have shown that fire enhances native species richness (see Harrison, Inouye, and Safford (2003) Ecological Heterogeneity in the Effects of Grazing and Fire on Grassland Diversity. Conservation Biology 17 (3), 837845). This suggests that fire can be used to manage native species diversity.
