The Christmas Tree that Keeps on Giving: the Invasive Potential of Cultivated Varieties of American Holly
Start Date
13-11-2015 8:00 PM
End Date
13-11-2015 9:59 PM
Description
The genetic, ecological, and demographic effects of invasive plant species have already been widely documented and studied. The effect of escaped cultivars of native species introduced outside of their natural range, however, has been given little to no attention. This preliminary study sought to locate and identify wild and escaped populations of American Holly (Ilex opaca), record sex ratios, and collect sample specimens for future genetic analysis. Site locations were provided by the Pennsylvania Natural Heritage Program. A voucher was collected for each observed population and small tissue samples were collected from individuals within a given population. After the first field season, the study revealed a few noteworthy trends: (1) at locations where Holly was believed to have escaped, high levels of recruitment were observed in shaded understories, (2) a number of populations were observed in riparian zones with noticeably saturated soil, perhaps indicating a selection for a broadened soil tolerance, and (3) Holly thrived in disturbed forests and edge habitats where other common invasive species occurred. Determining whether an individual was sexually mature proved difficult when drupes were not present. However, a slight male bias in some populations was observed. Upcoming comparisons of populations using genetic tools will determine future directions of the study.
Type
Poster
Language
eng
The Christmas Tree that Keeps on Giving: the Invasive Potential of Cultivated Varieties of American Holly
Elaine Langone Center, Terrace Room
The genetic, ecological, and demographic effects of invasive plant species have already been widely documented and studied. The effect of escaped cultivars of native species introduced outside of their natural range, however, has been given little to no attention. This preliminary study sought to locate and identify wild and escaped populations of American Holly (Ilex opaca), record sex ratios, and collect sample specimens for future genetic analysis. Site locations were provided by the Pennsylvania Natural Heritage Program. A voucher was collected for each observed population and small tissue samples were collected from individuals within a given population. After the first field season, the study revealed a few noteworthy trends: (1) at locations where Holly was believed to have escaped, high levels of recruitment were observed in shaded understories, (2) a number of populations were observed in riparian zones with noticeably saturated soil, perhaps indicating a selection for a broadened soil tolerance, and (3) Holly thrived in disturbed forests and edge habitats where other common invasive species occurred. Determining whether an individual was sexually mature proved difficult when drupes were not present. However, a slight male bias in some populations was observed. Upcoming comparisons of populations using genetic tools will determine future directions of the study.