Restoration Project

Yantai University - Xiaoheishan Island

Restoration Objective:

Given the essential function of macroalgal beds on rocky shores, much attention has been focused on effective methods to restore seaweed habitat on damaged rocky coastal ecosystems. The decline of S. thunbergii from extensive coastal areas highlights the urgent need to design effective strategies for restoration. This study aimed to develop restoration techniques for this species.

Site Selection Criteria:

Around the Xiaoheishan Island, five intertidal sites were selected where some patches of S. thunbergii were present in intertidal rock pools. The naturally growing thalli in the nearby rockpools were used as reference plants.

Cause Of Decline:

Rocky shore seaweed beds provide crucial habitats and spawning grounds for a wide variety of marine organisms and are an essential source of carbon for complex food webs in the rocky coastal ecosystems. However, these ecosystems have been severely affected by many anthropogenic activities, such as land reclamation, nutrient pollution, over exploitation and climate change. Consequently, many naturally occurring macroalgal beds have been seriously degraded in a number of coastal areas globally.

Key Reasons For Decline:

Multiple

Scientific Paper

Establishment of intertidal seaweed beds of Sargassum thunbergii through habitat creation and germling seeding

Y.Q. Yu, Q.S. Zhang, Y.Z. Tang, S. B., Z.C. Lu, S.H. Chu, X.X. Tang, , Ecological Engineering, Vol. 44.https://doi.org/10.1016/j.ecoleng.2012.03.016

Organisation:

Yantai University

Site Observations:

Observation Date

15th Jul 2010 – 15th Jul 2011

Action Summary:

Rectangular pools were constructed of high-strength cement, sand and water on a rocky intertidal platform. They were seeding with S. thunbergii germlings released from fertile thalli during low tide. These pools were covered with a double-layered shade net until the next tidal cycle to prevent germlings being dislodged.

Lessons Learned:

The construction of artificial rock pools coupled with seeding germlings in natural habitat may be an effective approach for the restoration of S. thunbergii, and potentially other seaweeds in rocky intertidal habitats.

Project Outcomes:

Most of the young germlings successfully attached to the artificial rock pool bottom. Two months after seeding, juvenile sporophytes attained a length of 15–20 mm. One year following seeding, S. thunbergii in the restored bed reached a density of 118.5 ± 13.2 thalli m−2, covered 32.7 ± 0.1% of the artificial substrate, and grew to an average length of 34.2 ± 1.6 cm with 7.3 ± 0.6 laterals per thallus. The proportion of fertile laterals of restored population was 73.6 ± 3.0%, indicating that these fertile thalli may serve as a source of new recruits to enhance the recovery of the algal population. Furthermore, restored S. thunbergii beds facilitated the presence of seven other species of macroalgae with species richness (R), diversity (H) and evenness (J) reaching 0.65 ± 0.04, 1.06 ± 0.09 and 0.67 ± 0.05, respectively.

Key Reasons For Decline:

Multiple

Area of Restoration (In Square Metres)

100

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Adult Kelp Density

118.5377358
/ m2
64.05660377
/ m2
Costings:
Cost Currency:USD