Latitudinal variation in the diversity and composition of various organisms associated with an exotic plant: the role of climate and plant invasion

Abstract

Climate and plant invasion can shape biotic communities at large spatial scales. Yet, how diverse groups of organisms associated with an invasive plant change simultaneously with latitude and the roles of climate and plant invasion remains unclear.We conducted a field survey of plants (native vs exotic), soil fungi (pathogenic, saprotrophic, arbuscular mycorrhiza fungi (AMF) and ectomycorrhizal (EcM) fungi) and arthropods (herbivores, predators and detritivores) associated with the invasive plant Alternanthera philoxeroides at 49 sites spanning 14 latitudinal degrees in China.Results showed that diversity and composition of these functional groups changed differently with latitude, partially due to their specific responses to climate, invasion of A. philoxeroides and other biotic environments. Moreover, A. philoxeroides invasion and/or composition of other plants, rather than climate, predicted the diversity and richness of major functional groups and partly explained variance in composition of putative fungal pathogens.Our results suggest that climate and plant invasion could affect the diversity and composition of diverse groups of organisms simultaneously and their relative importance might vary among functional groups. Thus, it is necessary to explore latitudinal patterns and underlying drivers of diverse groups of organisms simultaneously to improve our ability to predict and mitigate threats posed by plant invasion and climate change.

Aboveground herbivory can promote exotic plant invasion through intra‐ and interspecific aboveground–belowground interactions

“…In 2019, we collected rhizosphere soils (10 cm deep and 5 cm diameter, from five individuals) of the native and invasive plants at each site as described by Gao et al . (2021). Soils were shipped immediately to our laboratory, where we sieved (2 mm) and pooled soils sampled from the same species and site to control for spatial heterogeneity.…”

“…Soils were shipped immediately to our laboratory, where we sieved (2 mm) and pooled soils sampled from the same species and site to control for spatial heterogeneity. One-half of each pooled soil sample was stored at À20°C for sequencing soil bacteria and fungi as in Lu et al (2018), while the other half was air-dried for total carbon (TC) and nitrogen (TN) measurements and pH determination (Gao et al, 2021). To link rhizosphere community composition to climatic variability across our latitudinal transect, we used the WorldClim database variables to construct two principal component axes (BioPC1 and BioPC2, explained 57.9% and 30.3% of variance, respectively) explaining the majority of climate New Phytologist variation.…”

Leaf litter presence in the non‐growing season prolongs plant legacy effects on soil fungal communities and succeeding plant growth

“…In a laboratory, we sieved (2 mm) and homogenized the soil. We sampled 30 mL soil and divided it into two parts, which we stored at −80°C for DNA extraction or air-dried for measurements of total contents of carbon and nitrogen (TN) and pH (details please see Gao et al, 2021). After that, every 4 L of the topsoil was placed in 5 L experimental pots.…”

Plant invasion reconstructs soil microbial assembly and functionality in coastal salt marshes

“…It has been well documented that plant invasions have caused changes in the diversity and productivity of above-ground plants and belowground ecological processes that are closely related to plant-soil relationships (Liao et al, 2008;Sodhi et al, 2019). However, the limited knowledge of responses of microbial diversity and communities to plant invasion hinders our understanding of the link between above-and below-ground biodiversity and the consequences for microbially driven processes (Gao et al, 2021). We proposed and tested the following hypotheses: (i) the change in soil nutrient availability caused by plant invasion drives a succession of microbial communities along the invasion gradient; and…”

“…It has been well documented that plant invasions have caused changes in the diversity and productivity of above‐ground plants and below‐ground ecological processes that are closely related to plant–soil relationships (Liao et al, 2008; Sodhi et al, 2019). However, the limited knowledge of responses of microbial diversity and communities to plant invasion hinders our understanding of the link between above‐ and below‐ground biodiversity and the consequences for microbially driven processes (Gao et al, 2021). We proposed and tested the following hypotheses: (i) the change in soil nutrient availability caused by plant invasion drives a succession of microbial communities along the invasion gradient; and (ii) considering the distinct microbial niches that are occupied by bacterial and fungal communities as a consequence of their different cell size, morphology, biology and metabolic preferences, both groups are structured by contrasting ecological processes and therefore exert a distinct role in driving emerging properties (e.g., functional gene composition) of microbial communities under plant invasion.…”