Precipitation preferences alter the relative importance of herbaceous plant diversity for multifunctionality in the drylands of China

Abstract

BackgroundMultiple components of biodiversity are excellent predictors of precipitation-induced changes in ecosystem function. However, the importance of differing scales (alpha versus beta) is usually overlooked in biodiversity–ecosystem multifunctionality studies. Consequently, little is known about how precipitation regulates the relationship between multifunctionality and multiple components of alpha and beta diversity.AimsWe investigated geographic patterns of herbaceous plant diversity and ecosystem multifunctionality along a precipitation gradient spanning more than 2010 km in Northwest China.MethodsWe assessed the effects of herbaceous species, phylogenetic, and functional components at different scales on multifunctionality in drylands.ResultsThe alpha diversity of species and functional beta diversity were key components explaining the variation in multifunctionality. As the main environmental factor, MAP (mean annual precipitation) affected multifunctionality by changing the mediating variables (i.e., species alpha and functional beta diversity). More importantly, a certain precipitation threshold was detected for the relationship of multifunctionality to species alpha and functional beta diversity. MAPs of approximately 158 mm and 140 mm modulated this relationship (shifting it from uncorrelated to significantly correlated).ConclusionsOur findings provide insights into previously neglected mechanisms by which diversity in herbaceous layers at different scales affects ecosystem multifunctionality. It is highlighted that MAP regulates the relationship between diversity and multifunctionality in dryland ecosystems at different scales. Further, diversity may have substantial consequences for multifunctionality where MAP is higher. These empirical results provide a comprehensive understanding of the biodiversity–multifunctionality relationship in the context of precipitation, ultimately contributing to conservation and restoration programs for multifunctionality in drylands.

Ecosystem multifunctionality, maximum height, and biodiversity of shrub communities affected by precipitation fluctuations in Northwest China

“…This study proves that species beta diversity, which increases with longitude, positively correlates with ecosystem multifunctionality ( Figures 5 , 6 ). This result is similar to that of some studies showing that species beta diversity in arid regions may explain ecosystem multifunctionality better than species alpha diversity ( Grman et al., 2018 ; Guo et al., 2023 ). In natural ecosystems, biodiversity can enhance ecosystem multifunctionality through resource (niche) complementarity among species ( Soliveres et al., 2014 ).…”

“…In natural ecosystems, biodiversity can enhance ecosystem multifunctionality through resource (niche) complementarity among species ( Soliveres et al., 2014 ). Therefore, the establishment of stable communities requires the maintenance of multiple functions by constructing different combinations of species in heterogeneous environments (i.e., beta diversity) ( Grman et al., 2018 ; Guo et al., 2023 ). In other words, a community with a higher species pool should also have higher beta diversity, and thus, more reasonable cooperation between plants and resources ( Thompson et al., 2018 ).…”

“…Comparing with tree life form, shrubs tend to suffer from long-term constraints by environmental harshness, but we seem to pay insufficient attention to them. For example, in Northwest China, water scarcity is a constant threat to plant survival, and the higher the longitude, the faster and more intense the changes in water supply of shrub communities ( Zhang S. et al., 2022 ; Guo et al., 2023 ). There remains a lack of knowledge regarding how the ecosystem multifunctionality, maximum height, and biodiversity of shrub communities vary with this spatial gradient.…”

“…For example, species beta diversity (SD-beta) has been used to classify the floristic regions of Baja California ( Garcillan and Ezcurra, 2003 ). Some studies have suggested that functional diversity may be more effective than species diversity in predicting ecosystem functions ( Cadotte, 2017 ; Laughlin et al., 2020 ; Guo et al., 2023 ), perhaps because certain functional characteristics are related to how species participate in competition and use resources ( Valencia et al., 2015 ). Similarly, phylogenetic diversity (PD-beta) is an effective indicator of phylogenetic distance at the species and community levels.…”

“…Specific environmental drivers may cause long-term impacts on ecosystem functions and sustainability, and exhibit greater spatial heterogeneity with geographic gradients ( Loarie et al., 2009 ; Nishizawa et al., 2022 ). This study identified three environmental factors affecting the relationships between ecosystem multifunctionality, maximum height, and biodiversity of shrub communities: (i) Resource conditions (i.e., precipitation and temperature), which represent the overall resources obtained from a habitat to maintain plant growth and have been proven to be critical in stabilizing ecosystem functioning in arid regions ( Zhang X. et al., 2022 ; Guo et al., 2023 ). (ii) Climate stability during the growing season is critical for maintaining biodiversity and ecosystem functioning in drylands ( Souza et al., 2016 ; Lu et al., 2019 ).…”