Plant–plant interactions determine taxonomic, functional and phylogenetic diversity in severe ecosystems

Abstract

Aim Plant–plant interactions are an important factor in structuring plant biodiversity. However, most studies on the impacts of plant–plant interactions on biodiversity focus on species richness and to a lesser extent on other facets of diversity. When other facets of biodiversity are considered, studies often include a limited set of environmental conditions. We aimed to quantify the impacts of nurse plants on taxonomic, functional and phylogenetic facets of plant biodiversity and how these impacts change across environmental gradients. Location We report data on 28 alpine and 50 dryland sites, established in 11 countries. Time period 1998–2019. Major taxa studied Vascular plants. Methods We analysed plant–plant interactions using co‐occurrence analyses and obtained information on the functional traits and phylogenetic relationships of the beneficiary species. We calculated the change in taxonomic, functional and phylogenetic diversity caused by the presence of nurse plants and environmental conditions. Results Nurse plants enhanced taxonomic and phylogenetic diversity in alpine communities and enhanced functional and phylogenetic diversity in dryland communities. However, they had a positive effect on functional and taxonomic diversity only in moderate environments in alpine and dryland communities, respectively. The effects of nurse plants were larger in drylands for functional and phylogenetic diversity and in alpine communities for taxonomic diversity. Interestingly, nurse plants induced nonlinear changes in all facets of biodiversity across environmental gradients, whereas biodiversity tended to increase linearly toward more benign conditions in open interspaces. Main conclusions Facilitation is important in alpine environments to maximize taxonomic diversity and has a more consistent positive effect on the functional and phylogenetic diversity of drylands. In general, effects of facilitation on biodiversity peak in moderate environmental conditions, which suggests that nurse plants can protect biodiversity from impacts of climate change mostly in those places currently under low environmental stress and that will be likely to experience moderate stress levels in the future.

Plant–plant interactions determine natural restoration of plant biodiversity over time, in a degraded mined land

“…In contrast, the negative impacts of nurse plants on plant biodiversity were observed under severe environmental conditions (i.e., recent abandoned site). Therefore, we strongly confirm that positive impacts of nurse species are significantly associated with environmental or disturbance level considered (Bashirzadeh et al, 2022 ; Soliveres et al, 2015 ). In this regard, our results provide strong empirical support for positive impacts of nurse species to present a wide range of plant species under moderate disturbance conditions in concordance with stress‐gradient hypothesis (Michalet et al, 2006 ), and secondary succession as an important restorative process (Maestre & Cortina, 2004 ).…”

“…This result was consistent with the significant effects of Artemisia on plant biodiversity structure, especially on taxonomic diversity (Bahalkeh et al, 2021;Rahmanian et al, 2021)…”

“…However, biodiversity facets beneath nurse canopies may or not may exhibit consistent patterns depending on how functional traits conserve across phylogeny, as well as on levels of environmental harshness. For example, different responses of functional and phylogenetic diversity to nurse plant effects could be related to (1) functional traits that are not phylogenetically conserved (Valiente‐Banuet & Verdú, 2013 ; Vega‐Alvarez et al, 2019 ), and (2) functional traits that are labile because they cannot exhibit positive effects of nurse plants on beneficiary relatedness with an increase in environmental severity (Bashirzadeh et al, 2022 ). In this regard, some meta‐synthetic studies (Gomez‐Aparicio, 2009 ; He et al, 2013 ) show that growth form and some physiological traits such as leaf carbon and nitrogen content may clearly reflect plant strategies in response to major stress factors, including land use, land degradation, and changing soil nature in degraded ecosystems such as limestone mines (Wang et al, 2021 ).…”

Coordination of leaf functional traits under climatic warming in an arid ecosystem

“…The current results suggest that plants can cope well with the impacts of climatic warming in terms of LES theory but only when undergoing moderate climatic stress; the positive effect of the synergistic coordination between the traits is likely to attenuate, collapse, and even reverse under severe climatic harshness [ 40 ]. In addition, the current results from PCA illustrated that AM and MW had a similar pattern affecting the leaf functional traits (Fig.…”

“…Onoda et al (2004) indicated that PNUE has a negative relationship with SLA [ 39 ]. However, studies concerning the relationships between plant functional traits under diverse climatic warming scenarios are relatively scant, particularly in drylands (e.g., [ 2 , 8 , 40 ]).…”