Spatial Patterns Of Juniperus Virginiana And Lonicera Maackii On A Road Cut In Kentucky, Usa

We investigated the spatial patterns of several woody species that colonize disturbed sites, including the native Juniperus virginiana and the exotic Lonicera maackii. Our study site was on a road cut in northern Kentucky, USA, that faced NW and consisted of nine contiguous 25-m(2) quadrats. The positions of all woody plants : 50 cm in height were measured. Spatial patterns were quantified and compared with Ripley's K and the pair correlation function, which analyze the distribution of interplant distance at varying scales. For each woody plant, we also measured height, soil depth, and photosynthetically active radiation (PAR); the latter two measurements were taken at the four cardinal directions. Ripley's K showed that J. virginiana was distributed randomly, while L. maackii was clustered. Both J. virginiana and L. maackii were distributed independently of each other. Smaller L. maackii individuals clustered with larger ones, but this pattern was not seen in J. virginiana. Neither species appeared to associate with the other species. Mann-Whitney tests showed that L. maackii was found in areas of lower light than J. virginiana but there was only a weak indication of differences in soil depth means between these two species. These two species colonize disturbed sites in very different manners. L. maackii potentially facilitates establishment of its own species, whereas J. virginiana seedlings can only establish at some distances from parent trees. The different physiological requirements and growth forms of the two species appear to explain the lack of interaction between them. Though this project was limited to one study site, the methods can be used for multiple site analysis or on sites of varying size.