Effect of Aspect and Elevation on the Degree of Aggregation and the Functional Traits in Phlomis floccosa D. Don (Lamiacae) Populations

Abstract

Phlomis floccosa D. Don populations are distributed in different microhabitats within Al-Akhdar mountainous landscape, in Libya. Five populations were selected for the study. Spatial relationships among individuals were investigated using the spatial point pattern analysis. Functional traits were recorded at the vegetative, flowering and fruiting stages. Seeds were collected at the dispersal stage to estimate the regeneration potential. Greater degree of aggregation was found at higher elevations on both northern and southern sides of the mountain but with different demography and traits. On the northern side, greater degree of aggregation was accompanied by absence of large adults and greater percentage of seedlings, and it was positively associated with the reproductive output, while negatively associated with the size and regeneration indices. On the southern side, greater degree of aggregation was accompanied by greater contribution of large adults and greater percentage of seedlings, and it was positively associated with the size and regeneration indices, while negatively associated with the reproductive output. On the other hand, the population in the wadi (valley) microhabitat showed coarse-scale clumped pattern, higher values for most of the functional traits and higher contribution of seedlings but with lower facilitation offered by adults. The variations in the degree of aggregation and the functional traits trade-offs in P. floccosa populations ensured successful survival and regeneration in the heterogeneous microhabitats. Meanwhile, stressed conditions greatly affect the survival and regeneration of the species suggesting the need for conservation measures to overcome the adverse effects of climate change.