|Scientific Name:||Quercus acerifolia (E.J.Palmer) Stoynoff & Hess|
Quercus shumardii Buckley var. acerifolia E.J.Palmer
|Taxonomic Source(s):||Trehane, P. 2007-2015. The Oak Names Checklist. Available at: http://oaknames.org/search/goodnames.asp. (Accessed: 2 February 2016).|
|Taxonomic Notes:||Data accumulated by Stoynoff and Hess (1990) support the contention that the taxon is a species and not a variety of Q. shumardii.|
|Red List Category & Criteria:||Endangered B1ab(iii)+2ab(iii) ver 3.1|
|Assessor(s):||Wenzell, K., Kenny, L. & Beckman, E.|
Four occurrences of Maple-leaved Oak are currently known in the Ouachita Mountains of Arkansas (Logan, Montgomery, Polk and Sebastian Counties). The total population is believed to number fewer than 600 individuals, with just a few dozen to a few hundred individuals per locality. Its distribution is extremely restricted with an extent of occurrence (EOO) of 3,520 km2 and an area of occupancy (AOO) of between 7 km2 and 24 km2. Due to its highly restricted geographic range and small population size, combined with its small number of locations and the ongoing degradation of its habitat, Quercus acerifolia is considered Endangered.
|Previously published Red List assessments:|
|Range Description:||Endemic to the Interior Highlands (Ouachita Mountains region) of east-central Arkansas, USA, Maple-leaved Oak is restricted to four counties within the state. Occurrences are known from Magazine Mountain (Logan County), Sugarloaf Mountain (Sebastian County), Pryor Mountain (Montgomery County) and Porter Mountain (Polk County). This species has an extremely restricted range, with an extent of occurrence (EOO) of 3,520 km2 and an area of occupancy (AOO) of between 7 km2 and 24 km2, and only three locations (defined by the most serious plausible threats to those areas).|
Native:United States (Arkansas)
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||In 2003, a total population census found 527 Quercus acerifolia trees across four localities. The two largest occurrences contained 288 and 147 trees, while the smallest held only 53 and 39 individuals each. Though this report provided no information on the number of reproductive (mature) individuals, a recent collecting trip (October 2014) located only one reproductive individual (with a total of three acorns) at the one visited locality, suggesting low reproductive success (T. Boland pers. comm. 2015). Evidence of a cynipid wasp was observed and suspected as a possible cause of the low levels of reproductive success, due to abortion of developing acorns. Flowering was reported to have been strong in the spring of the previous year. |
If this cynipid wasp is found to be reducing acorn production drastically, and if these wasps are present at other localities, then the number of mature individuals (interpreted to be the number of trees that flower and produce viable offspring) may be much smaller than the estimated total population size of just over 500.
Additionally, the Sugarloaf Mountain occurrence, which constitutes the largest subpopulation, was reported to have 288 total (immature and mature) individuals in 2003. If the current number of mature individuals at Sugarloaf Mountain is below 250 and those individuals are also experiencing continuing decline, Q. acerifolia may qualify as Endangered under C2a(i) in addition to qualifying under criterion B.
|Current Population Trend:||Unknown|
|Habitat and Ecology:||Maple-leaved Oak grows as a small tree or large shrub, typically three to nine metres tall, and is distinctive due to its palmately lobed, maple-like leaves. This species favours early successional woodland habitats with open canopies. Quercus acerifolia is found on dry, rocky ledges, steep slopes, blufflines and open glades. It occurs most often on xeric sites with thin and rocky soils, but is known to occur in mesic, rich soils (though this habitat is considered altered and not ideal). Co-occurring species include Quercus stellata, Juniperus virginiana, Carya spp. and Fraxinus americana.|
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Use and Trade:||While Quercus acerifolia is not currently utilised or traded on a large scale, a 2003 report claimed that private landowners of one subpopulation had been approached by a commercial nursery with interest in acquiring seeds or plant material for cultivation and sale.|
Primary threats to Maple-leaved Oak are land use change and degradation, potential destruction of habitat and scientific specimen collection. The subpopulation at Sugarloaf Mountain in Sebastian County, which holds more than half of the total number of individuals, lies on privately owned land where no protective status or conservation agreement exists, as of 2003. Unrestricted access and recreational use of the site (resulting in camping, use of all-terrain vehicles and deposition of refuse and litter), as well as shale mining activity and electric tower construction, pose moderate threats. Furthermore, the private and unprotected nature of the land makes it vulnerable to development and destruction by future landowners.
Following Western settlement of the area, changes to the ecology of Magazine Mountain (where the second largest and best-documented occurrence is found) have disrupted the disturbance regime of the site. Suppression of fire has lead to a decline in the early successional open-canopy woodland in which Quercus acerifolia thrives.
Recent reports of a cynipid wasp possibly impacting acorn production at the Magazine Mountain location suggest another possible threat to this occurrence.
The Magazine Mountain occurrence, despite its proximity to recreation areas and campgrounds, is largely protected within the Magazine Mountain State Park, which strictly enforces rules regarding the plants. Occurrences at Pryor Mountain and Porter Mountain are located in remote areas with difficult terrain within the Quachita National Forest, and face little threat from human interference. The Porter Mountain site is further protected due to its inclusion in the Caney Creek Wilderness Area.
Quercus acerifolia is listed by NatureServe and the state of Arkansas as Critically Imperiled (G1S1), but it has not been federally listed as threatened or endangered by the U.S. Fish and Wildlife Service. Collection and propagation efforts are currently underway by several botanic gardens to support and maintain ex situ conservation of this species.
Additional research is need to examine the scope and severity of the cynipid wasp suspected to be impacting acorn production at at least one locality.
Efforts to arrange a protective agreement or conservation easement with the private landowners of Sugarloaf Mountain should be pursued, if not already in place.
|Citation:||Wenzell, K., Kenny, L. & Beckman, E. 2016. Quercus acerifolia. The IUCN Red List of Threatened Species 2016: e.T35039A2858212.Downloaded on 23 November 2017.|
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