Functional identity enhances aboveground productivity of a coastal saline meadow mediated by Tamarix chinensis in Laizhou Bay, China

Abstract

Research in recent decades has confirmed that biodiversity influences ecosystem productivity; however, the potential mechanisms regulating this process remain subject to controversy, due to variation across ecosystems. Here, the effects of biodiversity on ecosystem productivity were evaluated using three variables of biodiversity (taxonomic diversity, functional identity, and functional diversity) and surrounding environmental conditions in a coastal saline meadow located on the south coast of Laizhou Bay, China. At this site, the shrub and field layers were primarily dominated by Tamarix chinensis and natural mesic grasses, respectively. our results showed that functional identity, which is quantified as the community weighted mean of trait values, had greater explanatory ability than taxonomic and functional diversity. thus, ecosystem productivity was determined disproportionately by the specific traits of dominant species. T. chinensis coverage was a biotic environmental factor that indirectly affected ecosystem productivity by increasing the community weighted mean of plant maximum height, which simultaneously declined with species richness. the present study advances our understanding of the mechanisms driving variation in the productivity of temperate coastal saline meadows, providing evidence supporting the "mass ratio" hypothesis. With the increasingly severe decline in biodiversity, it is crucial to evaluate the underlying consequences on ecosystem functioning caused by biodiversity loss 1. Hence, the relationship between biodiversity and ecosystem functioning has been a hot and controversial topic in ecology in recent decades 2-5 , especially when considering ecosystem productivity across different vegetation types 6-9. Initial studies on biodiversity-productivity relationships mainly focused how taxonomic attributes (i.e. species richness as a traditional proxy of biodiversity) affect productivity 10-13. One study that reviewed hundreds of articles showed that the effects of taxonomic diversity on productivity cannot be predicted, with the underlying mechanism being equally complex 14. However, there is increasing evidence that functional traits represent the functional dissimilarity among species that coexist in a given community 15,16 , and that they are closely associated with niche difference processes. Thus, functional traits might have a stronger predictive power than taxonomic diversity on the biodiversity-productivity relationship 6,8,15,17. Several recent studies have also elucidated a clear link between productivity and the physiological traits of dominant species 4,16 , highlighting the relevance of the trait-based approach to explain the variation in community productivity 18,19. Two conceptually different, but not mutually exclusive, mechanisms have emerged to explain how biodiversity affects ecosystem productivity: (1) selection and (2) complementarity effects. Selection effects influence biomass accumulation determined by the dominance of species 20 with the highest yield or its function...

Soil‐associated drivers of plant traits and functional composition in Atlantic Forest coastal tree communities

“…When placing the selected predictors and the response variables in a multivariate context, we notice that the total aboveground biomass (TAGB) is indirectly influenced by the soil variables via their effects on plant height and basal area. Similar findings have been reported in other coastal wetland plant communities (Yi et al 2020) and tropical forests (Finegan et al 2015), including Amazon lowland habitat types with contrasting edaphic environments (Baraloto et al 2011), where forest biomass seems to be mostly driven by well‐coordinated changes in tree height and basal area across gradients of soil water availability (Hernández‐Calderón et al 2014). Although wood density (WD) has been claimed as an important parameter for the accurate estimation of forest biomass (Mitchard et al 2014), WD has an insignificant effect on TAGB, although plant communities strongly differ in WD values.…”

Soil habitat condition shapes Tamarix chinensis community diversity in the coastal saline-alkali soils

“…Numerous studies have found that a variety of soil determinants change plant community diversity and have used the results to develop a series of predicting models ( Wubs and Bezemer, 2018 ; Yi et al., 2020 ). Our study integrated soil determinants into the SHI to quantify soil habitat conditions, which eliminated the determinants’ multicollinearity and improved the accuracy of the prediction model.…”

“…In the Yellow River Delta, China's largest delta, wetland halophyte plants, especially T. chinensis, have developed widespread community patches and have made significant contributions to ecological functions due to their high salinity and waterlogging tolerance. Previous studies have reported that soil water, salinity, and nutrients significantly affect the T. chinensis plant community in the Yellow River Delta, but they only examined the influence of plant community diversity using a single soil index (Wu et al, 2020;Yang et al, 2021;Zhang et al, 2023). Therefore, they were unable to fully reflect the impact of the soil environment on T. chinensis plant community diversity.…”

Functional diversity along disturbance and environmental gradients in Ethiopian moist Afromontane forest

“…Response traits describe a plant's response to environmental change, while effect traits describe the effect of a plant on ecosystem functioning (Li et al, 2019). Functional diversity refers to the value, range, and distribution of functional traits in a specific ecosystem or to the components of biodiversity that have an impact on how an ecosystem operates or performs and are determined disproportionately by the specific traits (Yi et al, 2020). These traits mediate species' responses to environmental changes (Jesse et al, 2016); moreover, these changes point to mechanism alterations in ecosystem functioning and services (Nicola et al, 2021).…”