Assessing establishment success and suitability analysis of Zostera marina transplants using staple method in northern lagoons

Abstract

Aims Zostera marina populations in northern China are rapidly declining due to both natural and anthropogenic disturbances. Efforts to prevent further losses and restore disturbed Z. marina habitats through transplanting are desirable. In this study, a transplanting experiment was conducted using the staple method in Swan Lake, which is a typical lagoon in the Rongcheng region of Shandong Peninsula, China. The objectives of this research are to: 1) investigate the plant response in terms of survivorship, morphology, and growth; 2) assess the establishment suc- cess of transplants; and 3) analyze the suitability of applying staple method in northern China. Methods Ninety planting units (PUs, 3 shoots/PU) with 4-6 leaves and about 10 cm rhizome on each shoot were monthly transplanted using the staple method in the subtidal zone of Swan Lake (water depth 0.5 m) from April to September 2009. Ten replicated plots of 50 cm × 50 cm were set up and nine PUs were randomly planted in each plot. Survival rate was calculated as the percentage of PUs that survived. Shoot morphology and individual shoot biomass of transplants and reference plants in the donor bed were monthly monitored from May to December 2009. Important findings Survival rate of transplants planted during spring (April, May, and June) ranged from 76.5% to 90.4% with the minimum value in April; whereas the survival rate of transplants planted during summer (July, August, and September) was 100%. The time required for the establishment of transplants was on average 1.0 month when planted from June to September, 2.0 months when planted in May, and 4.0 months when planted in April. With exception of some monitoring months, the leaf length and sheath length of transplants were signifi- cantly lower than those of reference plants; whereas no significant differences were found in rhizome diameter and root length between transplants and reference plants. Habitat suitability analysis showed that transplanting site should be chosen in shallow subtidal zone (water depth <1 m) with high transparency and high-silted sandy mud