|Scientific Name:||Platanthera integrilabia (Correll) Luer|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Assessor(s):||Treher, A., Sharma, J., Frances, A. & Poff, K.|
Despite occurring across a relatively wide geographic range, Platanthera integrilabia is listed as Near Threatened because it has an area of occupancy (AOO) of 300–380 km2 and continuing declines in the area of occupancy and number of subpopulations. Although there are between 50 and 60 extant subpopulations, there were 90 subpopulations historically. Population declines continue in some subpopulations, and many subpopulations have fewer than 100 plants. There is at least one kilometre of unsuitable habitat separating the extant subpopulations, resulting in some, but not severe, fragmentation.
|Range Description:||Platanthera integrilabia occurs in the United States on the Appalachian Plateaus of Kentucky, Tennessee and Alabama, the Coastal Plain of Alabama and Mississippi, the Blue Ridge Province of Georgia, North Carolina (historic) and Tennessee; the Ridge and Valley Province in Alabama and the Piedmont of Georgia and South Carolina (FNA 2002, USFWS 2012). The extent of occurrence (EOO) is over 100,000 km2.|
Native:United States (Alabama, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, Tennessee, Texas, Virginia)
|Range Map:||Click here to open the map viewer and explore range.|
There are between 50 and 60 extant subpopulations with at least one kilometre of unsuitable habitat separating them. An additional 29 subpopulations are historic or extirpated. Some of these subpopulations were extirpated because of development (road, residential and commercial construction), impacts from off-road vehicle use and projects that reduced site suitability by altering soil and site hydrology (USFWS 2013).
Almost half of the subpopulations are located in Tennessee. Most subpopulations have less than 100 plants but some have been documented to have 500-1,000 plants (USFWS 2013). The largest subpopulation is in the Cherokee National Forest in Tennessee (USFWS 2013).
Due to different sampling techniques and count methods (flowering versus vegetative stems from year to year) population trends are hard to detect. General observations of declines in plant numbers and numbers of flowering plants are reported from Kentucky, Georgia and Tennessee, including at some of the largest subpopulations (USFWS 2013).
|Current Population Trend:||Unknown|
|Habitat and Ecology:|
Platanthera integrilabia is generally found in wet, flat, boggy areas in acidic muck or sand, and in partially, but not fully shaded areas at the head of streams or seepage slopes. Common associates include Sphagnum spp., Osmunda cinnamonea, Woodwardia areolata and Thelyptris novaboracensis (USFWS 2012). The species is associated with sandstones of the Appalachian Plateaus of Kentucky, Tennessee and Alabama, the Coastal Plain of Alabama and Mississippi, the Blue Ridge Province of Georgia, North Carolina and Tennessee; the Ridge and Valley Physiographic Province in Alabama, and the Piedmont of Georgia and South Carolina (FNA 2002, USFWS 2012). It occurs at elevations between 100 and 700 m asl.
Platanthera integrilabia flowers from late July through early September but as early as June in the southern portion of its range (Alabama). Fruits usually mature in October (Gleason and Cronquist 1991, Luer 1975, Shea 1992). Each plant grows from a single rootstock or tuber. In the winter season, two tubers can be found on one plant; one large tuber and a smaller more recently formed tuber. By spring, the tuber from the previous season (larger) will die back, and the new smaller tuber will supply energy for the upcoming growing season. The formation of the "same" plant from a new tuber can cause the vegetative shoot to "move" up to 15 cm from the previous year’s locale (Shea 1992, Zettler and Fairley 1990). The percentage of individuals flowering within a subpopulation is generally very low. Like many orchids, P. integrilabia has pollinia (pollen sacs which adhere to pollinators) that transfer pollen from plant to plant. Only about 3% of the wind-dispersed seeds germinate, which means plants have to produce copious amounts of seeds to overcome the high seed/seedling mortality. Some studies site other factors leading to low reproductive capacity including herbivory, inbreeding depression, and lack of effective pollinators (Bailey 2001, Zettler and Fairley 1990).
Despite the nocturnally sweet-scented, white-coloured, and long nectiferous spurred flowers which suggest sphingid moth pollination, Zettler et al. (1996) did not document nocturnal pollinators. They observed successful pollination by Epargyreus clarus, Papilio glaucus and Papilio troilus. When fertilization is absent, a membrane covering the pollinia deteriorates and self-pollination becomes possible (Argue 2011). The primary chemical attractant, which is common, in orchid nectars with strong evening odors is linalool (Hill 1968).
Platanthera integrilabia is a mycotrophic perennial herb that is an obligate wetland species. Research on the mycorrhizal fungal relationships of P. integrilabia suggests that the symbiont's, specifically Epulorhiza inquilina, presence may play a key role in the rate of seed germination (Currah et al. 1997, Yoder et al. 2000).
Vespids in search of nectar are known to visit and damage flowers by chewing through the sepals, petal, and spurs. Platanthera integrilabia is susceptible to fungal infections. Alternaria, Pestalotia, Nigrospora, and Cercispora have been isolated from the dead tissues of Platanthera integrilabia. These fungi genera contain known plant pathogens (Zettler and Fairley 1990).
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Use and Trade:||This species is not documented in the horticulture trade but it is wild collected, illegally, for the niche or speciality market or private collections.|
Threats to Platanthera integrilabia include habitat degradation (alteration, fragmentation, succession and forest management practices) and direct damage to individual plants. It also has a low reproductive capacity.
Habitat modification is the greatest threat to Platanthera integrilabia, especially actions like logging operations, development (commercial, residential), road projects, pond construction (related to agriculture), and beaver activities which can alter sites to become unnaturally wet by damming drainage. These activities disrupt and alter hydrological regimes, which have the most severe and long-term impacts on P. integrilabia subpopulations (Shea 1992). Although P. integrilabia may show an increase in reproduction and growth immediately after logging activities, which can continue for several years, the long-term effects have not been well studied (Shea 1992, Williams 2000). Additionally, shrubby secondary growth often follows logging, which may result in a decline due to shading and competition. The opening of the forest canopy may also provide habitat for aggressive non-native plant species. In 2000, Williams noted native species such as sedges, grasses and other herbaceous species can outcompete P. integrilabia in sites lacking an overstory. Other activities that disrupt surface water flow include ATVs, off-highway vehicles and horseback riding.
Damage to plants occurs through illegal harvest, herbivory by deer, feral hogs that uproot plants, disease and use of herbicides. In 1991, at least two nurseries in Tennessee were reported to have collected P. integrilabia plants for sale. It has been suggested the type locality in Kentucky was extirpated by plant collectors (Ettman and McAdoo 1979). Observations of herbivory by deer are common: deer favour the flowering stalks which decreases seed set. In addition, many orchids cannot replace loss of tissue until the next growing season. The loss of tissue from foraging animals could result in death for the plant (Sheviak 1990). In addition to lowering fruit set, herbivory can have a long-term negative impacts upon the site viability for the species (Zettler and Fairley 1990). Many sites occur in right-of-ways and these sites are subjected to herbicides to control vegetative growth. The manual or mechanical clearing of vegetation from the right-of-ways seems to benefit the species (Shea 1992).
Platanthera integrilabia is susceptible to fungal infections (Zettler and Fairley 1990).
Threats are compounded by low reproductive capacity and isolated subpopulations. It is unclear how much low seed set may be related to herbivory and lack of successful pollinators (Bailey 2001, Shea 1992, Williams 2000, Zettler and Fairley 1990).
Conservation actions currently in practice across the species range include monitoring subpopulations for status of threats, site condition and abundance of plants.
General recommendations include reviewing the most critical threats and consider the feasibility of their removal and how their removal will impact the quality of habitat for the species, as well as other species of interest. In Cherokee National Forest in Tennessee, fences were erected to exclude feral pigs from sites where they cause damage (USFWS 2013).
Consultation on future construction projects, logging activities and right-of-way maintenance could help to lessen their impacts on the species and its habitat. For example, it is recommended that mechanical methods to removed vegetation be used instead of herbicide. Other important considerations are actions to reduce siltation, soil compaction and reduce disruption to natural surface water flow.
Ongoing and past efforts should be consulted. The USFWS Species Assessment and Listing Priority Assignment Form (USFWS 2012) lists ongoing activities with agencies responsible for those actions.
The species occurs in several state natural areas and on National Forest land.Platanthera integrilabia is a candidate for protection under the U.S. Endangered Species Act. This species is listed on CITES Appendix II (CITES 2015).
|Citation:||Treher, A., Sharma, J., Frances, A. & Poff, K. 2015. Platanthera integrilabia. The IUCN Red List of Threatened Species 2015: e.T64176733A64176739.Downloaded on 15 August 2018.|
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