- Proposed
- Under Assessment
- Preliminary Assessed
- Assessed
- VUPublished
Sticta carolinensis T. McDonald
- Scientific name
- Sticta carolinensis
- Author
- T. McDonald
- Common names
- IUCN Specialist Group
Lichens- Kingdom
- Fungi
- Phylum
- Ascomycota
- Class
- Lecanoromycetes
- Order
- Peltigerales
- Family
- Lobariaceae
- Assessment status
- Published
- Assessment date
- 2020-08-01
- IUCN Red List Category
- VU
- IUCN Red List Criteria
- B2ab(i,ii,iii,v)
- Assessors
- Lendemer, J.
- Reviewers
- McMullin, T.
Assessment Notes
Justification
This species has an area of occupancy in the range of 432-532 km2, a severely fragmented population, and there are continuing declines in habitat quality observed and projected across its range. Tentatively, the higher estimate for the area of occupancy is used here, as this incorporates additional potential sites that have so far been unsampled. Thus, it is listed as Vulnerable under criterion B2ab(i,ii,iii,v). However, if further sites do not end up being found then the species could then warrant listing as Endangered.
Geographic range
Sticta carolinensis is endemic to south-eastern North America where it occurs from the southern Appalachian Mountains to the Coastal Plain (McDonald et al. 2003).Population and Trends
The population was likely naturally fragmented historically, occurring at sites in mature forest stands and spatially restricted habitat types. Where it occurs, the species is often locally abundant, occurring as 1-5 clustered functional individuals. The current population size is estimated at 690-1,380 individuals based on a conservative estimate of 5-10 functional individuals per site, and the known occurrence at 138 sites. We suspect that the population declined historically (during the last 3 generations; 90 years, based on a 30 year generation time) due to extensive of logging, habitat loss, and land use change throughout its range (Yarnell 1998, Martinuzzi et al. 2015). These activities have led the present extant population to become highly fragmented, as the species is restricted to mature forest stands in suitable habitat and these areas have become very limited in extent and are no longer contiguous (e.g. Ervin 2016). We suspect that the already fragmented and reduced population is currently decreasing due to numerous ongoing and projected trends in anthropogenic and climate change impacts that would directly affect this species (Keyser et al. 2014, Klepzig et al. 2014, Cartwright and Wolfe 2016).
Population Trend: decreasing
Habitat and Ecology
Sticta carolinensis primarily occurs on the bark of mature hardwood trees, although it also occasionally is found on shaded non-calcareous rock outcrops. It is restricted to high quality, mature forest stands and is typically associated with humid habitats such as riparian corridors and swamps.Threats
There are two primary pressures on this species, habitat fragmentation and loss (historical and ongoing) and impacts from air pollution and climate change (historical, ongoing and projected). The species occurs primarily in existing public land, some of which is large in overall area and some of which is protected from resource extraction and other impacts. However, the species naturally occurs in isolated locations where suitable habitat exists within large areas that are not suitable (i.e. mature forest stands with high humidity are spatially restricted within a matrix of younger forests, forests without appropriate tree hosts, drier habitats as well as more generally within a highly fragmented matrix anthropogenic land uses). These naturally dispersed locations were degraded and fragmented historically (last 90 years) due to extensive logging, building of roads, alteration of riparian corridors by dams, ditching/draining of swamps, air pollution, agriculture and urbanisation. All of these continue to be impacts to the species across its range, although threats vary depending on the individual site. Within the last 30-40 years, fragmentation has continued (Anderson et al. 2013, Klepzig et al. 2014) as the region has undergone rapid population growth. Available data indicate that the species is highly localised where it occurs. Furthermore, the region is currently experiencing climate change impacts (increased fire frequency and severity, droughts, sea level rise) and extensive alteration of forest communities due to invasive species, while increasing fires are also impacting habitat quality.
