Soon after its discovery in the 1980s, scientists believed that this small, dark brown butterfly had been collected to extinction, but it was rediscovered in 1992. Its habitat is open grassy wetlands maintained naturally by fire and beaver. The species is very dependent on disturbance and dynamic environments. Military activities on the artillery ranges also maintain the open wetland habitats in the absence of beaver. Disturbance can both create new habitats but also destroy existing habitats, so finding the ideal levels is necessary to help butterfly populations. Currently all known subpopulations are found on Ft. Bragg, an active military installation in central North Carolina.
The primary threats to the satyr when it was listed as endangered were overcollection and habitat loss. These threats remain relevant today, and without protection the likelihood of extinction would increase.
Since the emergency listing of the species in 1994 and simultaneous federal prosecution of illegal butterfly collectors, there has been no evidence of collection of the Saint Francis’ satyr other than minimal permitted collection for scientific purposes. However, poaching remains a significant threat to the satyr based on its extreme rarity and has required that all locations of all colony sites be kept strictly confidential.
It is likely that, historically, the Saint Francis’ satyr was more widespread in the sandhills region of North Carolina. Disappearance of beavers from the state, and loss of meadows created by their damming activities, was probably the biggest influence on the butterfly’s decline. The sole surviving metapopulation of this species now consists of numerous small colonies. This makes Saint Francis’ satyr more vulnerable to such threats as catastrophic climatic events, inbreeding depression, disease, and parasitism. Outside of the artillery ranges, there are only a few streams with butterflies, all of which require active restoration measures. Unlike populations inside artillery ranges, whose populations are extensive, not heavily fragmented, and regularly exposed to disturbance by fire and beaver, populations outside artillery ranges are heavily fragmented and lack the frequency and intensity of disturbance needed to maintain populations. Its small population size, limited dispersal ability and highly restricted distribution range make the butterfly highly vulnerable. Continued habitat restoration activities and captive-rearing efforts can be used to increase existing populations. Increased connectivity between butterfly populations will also be critical to ongoing conservation management goals.
Partnerships, research and projects
The ongoing investment of time and resources, and cooperation in management and access of Ft. Bragg, have been critical in accumulating knowledge of Saint Francis’ satyr biology and management. From 1994 to 2004, research into the life history of the butterfly was conducted by Steve Hall of the North Carolina Natural Heritage Program and Erich Hoffman of the Endangered Species Branch at Ft. Bragg (Hall 1993, Hall and Hoffman 1994, Hall et al. 2001, Hall 2003). Since 2002, Ft. Bragg managers have collaborated with Dr. Nick Haddad and his lab at North Carolina State University (note: Dr. Haddad and team have since moved to Michigan State University in 2017) to develop a partnership aimed at supporting a long-term monitoring and management plan.
These combined efforts have led to increased knowledge of population trends, species-habitat interactions, and species’ dependence on disturbance regimes (e.g. Hall et al. 2001, Hall and Haddad 2005, Kuefler et al. 2008, Haddad et al. 2009, Bartel et al. 2010, Cayton et al. 2015, Haddad 2015). The Ft. Bragg Endangered Species Branch has provided significant support in maintaining communication between military personnel and researchers and in obtaining access to restricted areas on base that are critical for researchers, in addition to lending aid for captive-rearing efforts. In coordination with the U.S. Fish and Wildlife Service, Ft. Bragg has developed a Saint Francis’ satyr research and monitoring program with specific goals and objectives in their Integrated Natural Resource Management Program to facilitate recovery efforts of the species. In 2011, partners began to restore habitat for the St. Francis’ satyr through a combination of hardwood removal and inundation via artificial dams to mimic natural beaver and fire disturbance. Restoration efforts have led to an increase in population sizes at restored sites.
Captive-rearing efforts have continued to be refined after initial studies with a surrogate species, the Georgia satyr. Since 2011, a captive-rearing program has been conducted in a greenhouse at Ft. Bragg. Expanded efforts have resulted in successful mating in captivity and researchers have maintained captive stock to release individuals at both historic and restoration sites on Ft. Bragg to promote population stability and growth.
The St. Francis’ satyr is bivoltine, with adults emerging in May through early June and again in July through early August. The onset of each of two flight periods can vary; the first flight period is highly predictable based on climate patterns classified into growing degree days, which accounts for heat input into ecosystems. The peak activity of the second flight period is approximately 62 days after the peak of the first flight period. The last brood overwinters in a larval stage and then resumes feeding and development before pupating in the spring. Caterpillars are very difficult to detect in the field and have only been observed twice since efforts began in 2002. A third flight period was detected four years in a row from 2015-2018 within a restoration area. Similar to other flight periods, these vary with weather patterns. The observed third periods occurred 53-63 days after the second flight period, usually occurring in early to late September and last 9-17 days (Cayton et al. 2019).
Males are more easily detected and more active than females, although they tend to have lower survivorship, and, in general, both sexes are highly sedentary. Individual butterflies are most active in the afternoon on sunny days but more likely to be observed on overcast or partly cloudy days (Kuefler et al. 2008). Adult lifespan is only a few days: 1.9 days during the first flight period and 3.9 days during the second flight period (Cayton et al. 2019).
The habitat occupied by this satyr consists primarily of wide, wet meadows dominated by a high diversity of sedges along small stream corridors. These meadows are often remnants of beaver activity and/or periodic wildfires. The vegetation can quickly succeed to a more closed canopy forest, and restoration actions are needed to maintain open high-quality habitats. Restoration activities include manual shrub and tree removal and manipulation of the stream network by the installation of temporary dams. Additionally, subpopulations of the satyr occur in artillery ranges on Ft. Bragg where the lack of roads, frequent fires, and beavers have allowed butterfly habitats to persist.
Butterflies consume a liquid diet. They mostly feed on nectar from flowers but also eat tree sap, dung, pollen, or rotting fruit. They are attracted to sodium found in salt and sweat. Butterfly caterpillars just eat leaves. Usually, each species relies on specific plants or plant families as hosts for their eggs and caterpillars. One known larval host plant for Saint Francis’ satyr is Carex mitchelliana, although it is likely that other sedges in the genus Carex may also act as host plants and provide nutrition during the larval stage.
St. Francis’ satyr adults are generally sedentary, but they will occasionally move between subpopulations, more likely if the sites are located within a single watershed (Kuefler et al. 2008). Dispersal of marked individuals between subpopulations has been infrequently observed and individuals have not been detected regularly moving along wetland or forest corridors to colonize new sites.
Adults generally do not feed on nectar. However, there are two confirmed observations of them feeding on flowers of sweet pepperbush (Clethra alnifolia) on two occasions late in the flight period (Hall et al. 2001, Haddad et al. 2004).
Saint Francis’ satyr is a small, dark brown butterfly. The wingspan for the species ranges from 34 to 44 millimeters. Saint Francis’ satyr has conspicuous “eye spots” on the lower surfaces of the wings. These eye spots have a dark maroon-brown center, and within the eye spots are lighter opalescent patches that reflect a silver cast. The border of these dark eye spots is straw-yellow in color, with an outermost border of dark brown. The eye spots are usually round to slightly oval and are well-developed on the fore wing as well as on the hind wing. The spots are accented by two bright orange bands along the posterior wing edges and two somewhat darker orange-brown bands across the central portion of each wing.
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