Reciprocal interactions between a facilitator, natives, and exotics in tropical alpine plant communities

The dark side of facilitation: native shrubs facilitate exotic annuals more strongly than native annuals

“…2, Tables 1, 2). This coincides with a number of recent studies (Maestre et al 2004, Poulos et al 2014Sheley and James 2014;Wright et al 2014;Reisner et al 2015;Llambi et al 2018). The relative importance (sensu Brooker et al 2005) of these biotic interactions likely depends upon abiotic conditions and the ontological development of interacting species (Callaway et al 1996;Fagundes et al 2018;Gao et al 2018;Pierce et al 2018).…”

“…Facilitation is an important process in the assembly of plant communities in drylands and other extreme environments globally (Callaway 2007), but few studies have contrasted the effects of native foundation species on native vs. exotic beneficiary species (but see Reisner et al 2015;Ramírez et al 2015;Hupp et al 2017;Llambi et al 2018). Understanding how ecological processes affect native and exotic taxa has important implications for the conservation of ecosystems affected by biological invasions (Simberloff et al 2013, Pearson et al 2018.…”

Climate Vulnerability Assessment of the Espeletia Complex on Páramo Sky Islands in the Northern Andes

“…The fact that diverse areas in the Eastern Cordillera are vulnerable to climate change is not only counterintuitive, but it also means that the long-term rapid diversification rate, striking in the Espeletia complex, could be jeopardized. Diversity is regarded as a buffer of the effects of climate change by enriching interactions (Cáceres et al, 2014), such as facilitation (Bueno and Llambí, 2015;Wheeler et al, 2015;Llambí et al, 2018;Mora et al, 2018;Venn et al, 2019), adaptive inter-specific introgression (Schilthuizen et al, 2004;Seehausen, 2004) and hybrid speciation (Payseur and Rieseberg, 2016), of which there is abundant evidence in Espeletia (Rauscher, 2002;Cuatrecasas, 2013;Cortés et al, 2018a;Pouchon et al, 2018). Yet, these positive effects are offset by distribution losses in sensitive Páramo localities, besides rising mining, agriculture and population density.…”

Positive associations with native shrubs are intense and important for an exotic invader but not the native annual community across an aridity gradient

“…Most empirical studies of plant invasions have focused on negative interactions, that is competition and predation (reviewed by Jeschke et al, 2012;Maron & Vila, 2001;Mitchell et al, 2006;Roy, Lawson Handley, Schonrogge, Poland, & Purse, 2011), but positive interactions can also influence invasion trajectories (reviewed by Simberloff, 2006;Travaset & Richardson, 2014). In this context, native species in deserts can exacerbate plant invasions by strongly facilitating the abundance (Lucero et al, 2019;Schafer et al, 2012), performance (Holzapfel & Mahall, 1999) and population growth (Griffith, 2010) of invasive plant species, or by indirectly increasing the competitive effects of invasive species on native neighbours (Llambi, Hupp, Saez, & Callaway, 2018;Reisner, Doescher, & Pyke, 2015). There is some evidence that the intensity of positive interactions between native and invasive species can vary along environmental gradients (Badano, Villarroel, Bustamante, Marquet, & Cavieres, 2007;Saccone, Pages, Griel, & Michalet, 2010), but very few dryland studies have measured the intensity and importance of such interactions along an aridity gradient.…”