Ecosystem engineers maintain a rare species of butterfly and increase plant diversity

Abstract

We evaluated whether ecosystem engineers can accomplish two conservation goals simultaneously: (1) indirectly maintain populations of an endangered animal through habitat modification and (2) increase riparian plant diversity. We tested for effects of a prominent ecosystem engineer, the beaver Castor canadensis, on populations of St. Francis' satyr butterfly Neonympha mitchellii francisci and plant species richness and composition. We performed our test by surveying riparian vegetation communities in all stages of beaver‐influenced wetland succession. We found that beavers created wetland habitats that supported plant species not found elsewhere in riparian zones and increased plant species diversity across the landscape by creating a novel combination of patch types. Our results confirmed what others have found about engineering effects on plant diversity, but these results further demonstrated a case where ecosystem engineers indirectly maintain populations of rare animals by modifying the composition and diversity of plant communities within wetlands. Our research demonstrates how an ecosystem engineer can influence habitat availability and composition of plant communities important for an endangered insect, and maintain overall plant species diversity by increasing habitat heterogeneity.

Dispersal via stream corridors structures populations of the endangered St. Francis’ satyr butterfly (Neonympha mitchellii francisci)

“…The larval food plant of N. m. francisci, likely a sedge in the genus Carex, is among the early successional vegetation that emerges after a beaver impoundment is abandoned (Hall 1993;Hall and Haddad 2005). As the sedges and grasses succeed to shrubby and woody vegetation, the habitat quickly becomes unfavorable for N. m. francisci (Bartel et al 2010). In some cases, fire can set back succession.…”

“…N. m. francisci are associated with dynamic, early stage wetlands located along streams. These wetlands are created by beaver impoundments that are subsequently abandoned (Bartel et al 2010). The larval food plant of N. m. francisci, likely a sedge in the genus Carex, is among the early successional vegetation that emerges after a beaver impoundment is abandoned (Hall 1993;Hall and Haddad 2005).…”

The influence of wild boar (Sus scrofa) on microhabitat quality for the endangered butterfly Pyrgus malvae in the Netherlands

“…These might offer an added value in habitat management. Documented examples are still rare, but have been found in the abandoned pond meadows created by beaver (Castor canadensis) benefiting the butterfly Neonympha mitchellii francisci (Bartel et al 2010), ant mounds from Lasius flavus favouring the butterfly Hesperia comma (Streitberger and Fartmann 2016), and mounds created by mole (Talpa europaea) that offer suitable microhabitat for the butterfly Pyrgus malvae (Streitberger and Fartmann 2013).…”

Native herbivore exerts contrasting effects on fire regime and vegetation structure

“…Thus, potential effects of vizcachas on community and ecosystem processes can extend over large spatial scales (see also Branch et al 1996;Villarreal et al 2008). Possible variations in resource availability, predation levels, and competition intensity between patches of unburned vegetation created by vizcachas and surrounding burned sites could influence patterns of species diversity, as has recently been shown for alterations caused by other ecosystem engineers (Wright et al 2002(Wright et al , 2006Bartel et al 2010). In addition, the increase in shrub age and biomass induced by vizcacha-fire interactions could impact the reproductive output and productivity of shrubs.…”