In the context of this study, I predicted that a more heterogeneous riparian ecosystem would have higher total woody species richness, which would be mostly due to

the presence of sclerophyllous plants in addition to (rather than replacing) strictly Trichostatin A molecular weight riparian plants. The findings in this study corroborate this prediction; as total richness increases, sclerophyllous species richness increases at a similar rate, while riparian species richness has a lower effect (Fig. 2). However, from the negative relationship between richness and presence of human activities it can be inferred that increased sclerophyllus richness does not seem to be a function of the structure of the riparian ecosystem. Human activities in the riparian ecosystem included development of roads, fences, walls, houses, and artificial water channels, which in turn create higher fragmentation and gaps within the riparian

vegetation. Furthermore, changes in water rights policies have altered the management prescriptions for riparian zones, allowing neighbouring land-owners to clear-cut riparian trees for easier access to water. These factors have also been identified by other authors as major causes of the decrease in strictly riparian richness in other riparian areas (Aguiar and Ferreira 2005; Hilty and Merenlender Vincristine concentration 2004; Malanson 1993; Miller 2002; Pollock et al. 1998; Salinas et al. 2000; Tabacchi et al. 2002). However, this

effect may be only temporary, matching Pollock et al. (1998) pattern of different seral stages. Younger seral stages will be dominated by riparian plants, and as sclerophyllous species may colonize gaps, mixed mosaics of riparian and sclerophyllous plant species appear as older seral stages, resulting ultimately in an increase in total species richness. This study results also revealed that riparian species richness (total and strictly riparian) was positively affected by the presence of a developed shrub layer and it was negatively affected by the presence of goats. The most commonly found shrub species in the study area were blackberry shrubs (79.5%), and rock-rose (36.1%). While the first is mostly found in riparian areas, the second is a sclerophyllous Thalidomide shrub. Blackberry shrubs are probably the most related to the observed positive influence on riparian richness, since they are the ones most detected. Blackberry shrubs tend to create a very dense canopy, which may prevent light from reaching the riparian species seeds; however, willows and poplar seeds are known to germinate in the dark (Karrenberg et al. 2002). Thus, blackberry bushes may facilitate the germination seeds from these species, which occurs in a short period (a few days), and also prevent seed mortality from desiccation by providing shade (Karrenberg et al. 2002).