Spatial Patterns of Juniperus virginiana and Lonicera maackii on a Kentucky road cut

This study investigated the spatial patterns of several woody plant species on a road cut site in Northern Kentucky with particular focus on eastern red cedar (Juniperus virginiana) and Amur honeysuckle (Lonicera maackii). The site faced NW and consisted of nine 25-m 2 quadrats. The positions of all woody plants 50 cm and taller were measured. 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 points. Ripley's L showed that J. virginiana and Bradford pear (Pyrus calleryana) were distributed randomly while the remaining species were clustered, especially L. maackii. White ash (Fraxinus americana), J. virginiana, and L. maackii distributions were independent of other species, while red panicle dogwood (Cornus racemosa) and P. calleryana both showed a slight association with other woody plants. Mann-Whitney tests showed that L. maackii was found in areas of lower light than J. virginiana and that C. racemosa was found in deeper soils than J. virginiana. Smaller L. maackii individuals clustered with larger ones, but this pattern was not seen in J. virginiana. Nonparametric Mann-Whitney tests were used to analyze PAR and soil depth data (means, minimum, and maximum values). Ripley's K function was used to analyze the coordinate data to determine distribution, scale of distribution, and associations of each plant relative to other plants, with focus on Juniperus and Lonicera. Monte Carlo randomizations were run 1000 times for distribution determination and 5000 times for association determination. The library splancs was used in the program R for the analysis of these data (Rowlingson and Diggle 1993; R Development Core Team 2004). A more easily interpreted transformation of Ripley's K uses an estimator L and is defined as (Goreaud & Pelissier 2000) :