Ecosystem engineering across ecosystems: do engineer species sharing common features have generalized or idiosyncratic effects on species diversity?

Aim To integrate the effects of ecosystem engineers (organisms that create, maintain or destroy habitat for other species) sharing the same archetype on species diversity, and assess whether different engineer species have generalized or idiosyncratic effects across environmentally similar ecosystems. Location High-Andean habitats of Chile and Argentina, from 23 degrees S to 41 degrees S. Methods We measured and compared the effects of eight alpine plants with cushion growth-form on species richness, species diversity (measured as the Shannon-Wiener index) and evenness of vascular plant assemblages across four high-Andean ecosystems of Chile and Argentina. Results The presence of cushion plants always increased the species richness, diversity (measured as the Shannon-Wiener index) and evenness of high-Andean plant assemblages. However, while the presence of different cushion species within the same ecosystem controlled species diversity in the same way, these effects varied between cushion species from different ecosystems. Main conclusions Results consistently supported the idea that increases in habitat complexity due to the presence of ecosystem engineers, in this case cushion plants, would lead to higher community diversity. Results also indicate that effects of the presence of different cushion species within the same ecosystem could be generalized, while the effects of cushion species from different ecosystems should be considered idiosyncratic.