Simultaneous, independent, and additive effects of shrub facilitation and understory competition on the survival of a native forb (Penstemon palmeri)

Size-related change in Nitraria sphaerocarpa patches shifts the shrub-annual interaction in an arid desert, northwestern China

“…This can probably lead to a strong underground niche overlap between N. sphaerocarpa and their understory plants, and partly explain the negative shifting in shrub-understory plant interactions with increase in patch size. As reported in previous studies, this root competition from mature plants can reduce the survival of their understory species (Good et al, 2014;Shiponeni et al, 2014), or lead to an overall neutral planteplant interaction (Poulos et al, 2014). On the other hand, the interaction shift may also result from direct impacts by shrub canopies.…”

“…Although positive interactions between shrubs and their neighbors are very common in stressed environments, shrubs can also have profoundly negative effects on many aspects of the understory plants, such as seedling performances (Poulos et al, 2014), plants diversity (Rayburn and Schupp, 2013), species coexistence (Maestre et al, 2009), and spatial patterns (Li et al, 2010). Over the past decade, numerous studies indicated that the balance between facilitation and interference may well depend on environmental context (Lortie and Callaway, 2006;Michalet, 2006;Maestre et al, 2009;He et al, 2013).…”

“…Recent studies further indicate that the shift in planteplant interactions not only depends on spatial or temporal variation in environmental stresses (García-Cervig on et al, 2013;Biswas and Wagner, 2014;Poulos et al, 2014), but may also be related to ontogeny or adaptive strategy of interacting species and the nature of stress gradients (Armas and Pugnaire, 2009;He and Bertness, 2014). The vegetation in most water-limited communities is organized as an array of dispersed natural patches, which are usually modulated by shrubs, due to their crucial role in trapping seeds, changing hydrological properties, and ameliorating micro-habitat environment (Giladi et al, 2013).…”

The role of nurse successional stages on species‐specific facilitation in drylands: Nurse traits and facilitation skills

“…Nurse effects, however, might vary from positive to negative depending on the target species that establishes under nurse crown, and this process is referred as a species-specific interaction outcome (Callaway, 1998;Callaway & Walker, 1997). Species-specific interaction outcomes have been found to occur in a wide range of ecosystems (Landero & Valiente-Banuet, 2010;Paterno, Siqueira, & Ganade, 2016;Poulos, Rayburn, & Schupp, 2014) and have been pointed out as a strong factor modulating seedling regeneration in plant communities (Paterno et al, 2016). However, predicting the outcome of nurse-target interactions can be difficult, especially in high diversity ecosystems where multiple pairs of nurse and target species are able to interact.…”

Long-term restoration success of re-sprouter understorey species is facilitated by protection from herbivory and a reduction in competition

“…Second, the already established plants may provide a positive 'nurse' plant effect (e.g., Close et al 2010) via either physical (e.g., spines) or chemical (e.g., toxins) protection from herbivory or by simply reducing the visibility of newly established plants to herbivores (Smit et al 2007). However, while this strategy might reduce herbivory, beneficial effects from nurse plant are not consistently observed in restoration studies since increased competition resulting from the close proximity of neighbours can outweigh facilitation effects (Gómez-Aparicio et al 2004;Caldeira et al 2014;Poulos et al 2014): facilitation is most likely to be observed with increasing abiotic stress.…”