Lakeshore plant removal intensifies microbial phosphorus limitation and weakens multinutrient cycling-bacterial diversity relationship.

Rational management of lakeshore plants can achieve ecological protection and restoration purposes for lakes, whereas influences of lakeshore plant removal on microbial nutrient limitation and linkage between biodiversity and multinutrient cycling (MNC) remain largely unclear. Molecular and statistical analyses were adopted to reveal responses of microbial nutrient limitation and MNC to lakeshore plant removal as well as bacterial adaptability to environmental changes. Activities of sediment enzymes targeting carbon, nitrogen, and phosphorus cycles notably decreased after plant removal, and lakeshore plant removal rather than seasonal variation showed larger effects on enzyme activities, ecoenzymatic stoichiometric parameters (i.e., C:N, C:P, and N:P acquisition ratios), and vector analysis parameters (i.e., length and angle). Lakeshore plant removal aggravated sediment microbial phosphorus limitation, and lakeshore plant removal elevated abundances of phosphorus-cycling genes. There was a notable increase in MNC in the water-sediment system after plant removal, and non-nutritional physicochemical factors and phosphorus-cycling genes directly and indirectly affected MNC. There were declined linkages between MNC and taxonomic and phylogenetic α-diversities of water and sediment bacteria after plant removal, and non-nutritional physicochemical factors and phosphorus-cycling genes directly and indirectly influenced bacterial diversity. Environmental breadths of bacteria in water and sediment declined after plant removal. Phylogenetic signals of bacteria in water declined after plant removal, but opposite for sediment bacteria. Our results highlighted ecological consequences of lakeshore plant removal regarding microbial nutrient limitation and bacterial diversity maintenance, and findings could guide lake protection and restoration by weakening linkage between bacterial diversity and MNC in water-sediment systems.