Abstract Detail

Ecophysiology

Boyd, Jennifer [1], Raymond, Gregory [2], Call, Geoff [3], Pistrang, Mark [4].

Adaptive leaf-level physiology exhibited by the rare terrestrial orchid Platanthera integrilabia across contrasting habitats.

Platanthera integrilabia (white fringeless orchid) is a rare terrestrial orchid species generally associated with semi-open forested wetlands in the southeastern U.S. It has been suggested that P. integrilabia has restrictive abiotic resource requirements; however, these requirements have not been implicitly studied despite their potential application to species conservation. We investigated the influence of light and soil moisture availability on P. integrilabia at landscape and local scales and population and organismal levels across and within four occurrences with contrasting canopy openness. We also evaluated the potential for adaptation and plasticity of leaf-level physiological responses of this species to light and soil moisture to influence its habitat suitability and performance. At landscape scales, light and soil moisture availability were not associated with P. integrilabia density or individual size. Across sites, photosynthetic light-response and water-use efficiency indicated that P. integrilabia can adapt to maximize photosynthetic efficiency and energy gain in contrasting light and soil moisture environments. Minimal associations of these measures with abiotic variations at more local scales suggested that photosynthetic trait plasticity may be limited, but could be influential in some populations. Preservation of existing habitats associated with viable P. integrilabia occurrences is warranted. But the adaptive leaf-level physiology of this species suggests that its habitat suitability can vary across populations to also include more open and drier sites. For populations experiencing declines in habitats that have experienced recent disturbance, we suggest the possibility that well managed modifications to canopy cover may be beneficial.

1 - University of Tennessee at Chattanooga, Biology, Geology, and Environmental Science, Dept 2653, 615 McCallie Avenue, Chattanooga, TN, 37403, USA
2 - University of Tennessee at Chattanooga, Biology, Geology, and Environmental Science
3 - U.S. Fish and Wildlife Service, Tennessee Ecological Services Field Office, 446 Neal Street, Cookeville, TN, 38501, USA
4 - U.S. Forest Service, Cherokee National Forest, Cleveland, TN, 37312, USA

Keywords:
orchid
local adaptation
Ecophysiology
photosynthesis
Plantanthera
endemic/rare.

Presentation Type: Oral Paper
Session: 3, Ecophysiology
Location: 104/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 11:00 AM
Number: 3012
Abstract ID:249
Candidate for Awards:None