A field experiment exploring disturbance‐and‐recovery, and restoration methodology of Zostera capensis to support its role as a coastal protector

Abstract

Seagrass degradation in the western Indian Ocean is of serious concerns with numerous severe climate events that has impacted Mozambique, as well as South Africa in recent time, highlighting the need for re‐establishing these critical habitats. The following paper present a field experiment from Mozambique concerning disturbance‐and‐recovery effects of Zostera capensis, a highly impacted seagrass species in the region. We undertook trials mimicking disturbance of meadows in terms of digging to collect clams, a common practice in Maputo Bay. Our results indicated that once such anthropogenic impacts are halted, Z. capensis meadows restore itself after 12 months of impact exclusion. In addition, we also conducted seagrass restoration experiment using a manual method, the so‐called plug method which, demonstrated to improve the survival rate with 75%, which has large implications for seagrass transplantation projects that are both time consuming and financially costly. The results from this study will further guide the appropriate management to build the best practice in seagrasses meadows restoration and awareness. It is clear from this study that a combination of both impact exclusions and active restoration is bound for best results of seagrass management actions.

Investigating transplantation as a mechanism for seagrass restoration in South Africa

“…Matheson et al (2022) indicated that 5 cm Ø cores for Z. muelleri were also effective, suggesting that optimal core size is likely to be species‐specific. For example, for Z. capensis in Mozambique, Amone‐Mabuto et al (2023) noted that 7.5 cm Ø cores had higher survival rate compared to 4.5 cm Ø. Syringodium isoetifolium also indicated better survival of 10 cm Ø compared to 7 cm Ø cores (Wegoro et al 2022). For this study, no significant differences were observed in transplanting for the different core sizes in either study site.…”

“…Considering that the species does not colonize quickly, there is a continued decline of Z. capensis in many estuaries (Adams 2016). Apart from Amone-Mabuto et al (2023), which focused on restoration of Z. capensis in Maputo Bay, Mozambique, restoration of this regionally endangered seagrass has received little scientific attention. Furthermore, intersite comparisons are lacking, yet such data are critical for estuaries that experience wide variations in their physicochemical parameters.…”

Intertidal Gleaning Exclusion as a Trigger for Seagrass Species and Fauna Recovery and Passive Seagrass Rehabilitation

“…H. uninervis is tolerant to sedimentation and burial [27,28]. Z. capensis, has a low elongation rate since this species is rather adapted to strong tidal currents and long exposing periods, at least in South Africa [19]; nonetheless, BP may experience rather long exposition periods, and tidal currents are moderate [20]. Z. capensis recovery can take one year, as documented [20].…”

“…Prior to the fieldwork, gleaner communities were sensitized about the purpose of the no-take plots placed through informal conversations (cf. [20]). The unofficial conversations were conducted during the preliminary phase of the study as adapted from elsewhere [21] and were limited to gleaners that demanded the site during the low tide periods.…”

Introduction – Nature‐Based Solutions for Coastal Protection

“…The paper offers examples of best practise but also identifies challenges, with examples taken from countries in developed as well as developing parts of the world. In the fourth chapter (Amone‐Mabuto et al 2023), field experiments of seagrass restorations from the Western Indian Ocean are presented. The researchers examine various planting techniques to develop guidance for conservation actions and appropriate management to build and improve guidance for seagrasses meadows restoration and awareness.…”