Resistance of plant–plant networks to biodiversity loss and secondary extinctions following simulated environmental changes

Abstract

Summary Plant interactions are fundamental processes for structuring plant communities and are an important mechanism governing the response of plant species and communities to environmental changes. Thus, understanding the role played by the interaction network in modulating the impact of environmental changes on plant community composition and diversity is crucial. Here, we aimed to develop a new analytical and conceptual framework to evaluate the responses of plant communities to environmental changes. This framework uses functional traits as sensitivity measures for simulated environmental changes and assesses the consequences of microhabitat loss. We show here its application to an alpine plant community where we recorded functional traits [specific leaf area (SLA) and leaf dry matter content (LDMC)] of all plants associated with three foundation species or the surrounding open areas. We then simulated primary species loss based on different scenarios of environmental change and explored community persistence to the loss of foundation species. Generally, plant community responses differed among environmental change scenarios. In a scenario of increasing drought alone (i.e. species with lower LDMC were lost first) or increasing drought with increasing temperature (i.e. species with lower LDMC and higher SLA were lost first), the plant community resisted because drought‐tolerant foundation species tolerated those deteriorating conditions. However, in scenarios with increasing nitrogen input (i.e. species having lower SLA were lost earlier), foundation species accelerated species loss due to their early primary extinctions and the corresponding secondary extinctions of species associated to their microhabitat. The resistance of a plant community depends on the driver of environmental change, meaning that the prediction of the fate of this system is depending on the knowledge of the main driver of environmental change. Our framework provides a mechanistic understanding of an ecosystem response to such environmental changes thanks to the integration of biology‐informed criteria of species sensitivities to environmental factors into a network of interacting species. A http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.12839/suppinfo is available for this article.

Plant interactions shape pollination networks via nonadditive effects

“…, Kikvidze et al. , Losapio and Schöb ). These two foundation species enable plant coexistence providing positive facilitative effects on other associated plant species through the improvement of their physiological status (Schöb et al.…”

“…S2). In this well-established model ecosystem, beneficial and harmful effects of plant facilitation have been studied for several years (Callaway et al 2002, Sch€ ob et al 2012, 2014, Cavieres et al 2014, Kikvidze et al 2015, Losapio and Sch€ ob 2017. These two foundation species enable plant coexistence providing positive facilitative effects on other associated plant species through the improvement of their physiological status (Sch€ ob et al 2012(Sch€ ob et al , 2013.…”

“…) and stability (Levine et al. , Losapio and Schöb , Mayfield and Stouffer ). A growing literature examines the effects of competition and facilitation among plants for the structure of insect communities (Ghazoul , Valiente‐Banuet and Verdú ).…”

“…Plants grow in communities where they interact with other plants (Tilman 1994, Callaway et al 2002, Levine et al 2017, Mayfield and Stouffer 2017 and with other organisms such as pollinators (Bascompte et al 2003, Bastolla et al 2009, Bronstein 2009). The consequences of plant interactions are fundamental for plant community diversity (Bruno et al 2003, Cavieres et al 2014, Kikvidze et al 2015 and stability (Levine et al 2017, Losapio and Sch€ ob 2017, Mayfield and Stouffer 2017. A growing literature examines the effects of competition and facilitation among plants for the structure of insect communities (Ghazoul 2006, Valiente-Banuet andVerd u 2013).…”

The assembly of a plant network in alpine vegetation

“…Plant traits such as leaf mass per area, height and diameter reflect species competitive ability (Gross et al., ) and are therefore related to the assembly of plant communities (Schöb, Butterfield, & Pugnaire, ). The sensitivity of plant traits to environmental conditions further allows prediction of the effects of environmental change on plant communities (Losapio & Schöb, ). Plant traits may therefore be a suitable tool for assessing the dependence of plant association networks on environmental conditions.…”