A Review of Seagrass Cover, Status and Trends in Africa

Estuaries and Coasts, Journal Year: 2024, Volume and Issue: 47(4), P. 917 - 934

Published: March 22, 2024

Abstract The recognition of the benefits that seagrasses contribute has enhanced research interest in these marine ecosystems. Seagrasses provide critical goods and services support livelihoods millions people. Despite this, they are declining around globe. To conserve ecosystems, it is necessary to understand their extent drivers leading loss. However, global seagrass cover estimates highly uncertain there large regional data gaps, especially African continent. This work reviewed all available on cover, evidence changes this change Africa, inform management conservation approaches across continent identify gaps knowledge. Using a systematic review expert consultation, 43 relevant articles were identified. Of 41 countries with coastline, 27% had no cover. For 44%, for some parts while 29% entire coastline. Quantitative information trends was only from three countries. study identified 32 suggested loss, impacts fishing mentioned most frequently. Direct anthropogenic accounted 66.7% mentions, climate biologically induced 22.7% 10.6%, respectively. demonstrates need better extent, at least 70% nations, major our understanding decline Africa.

Language: Английский

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Investigating transplantation as a mechanism for seagrass restoration in South Africa

Restoration Ecology, Journal Year: 2023, Volume and Issue: 31(7)

Published: May 22, 2023

The extent of seagrasses has declined globally, with restoration through transplantation seen as an important tool for reversing population loss, yet studies African seagrass species are scarce. This study investigated the use different planting patterns (straight‐line, compact, and star) core sizes (11, 18, 25 cm Ø) in transplanting ecotypes (intertidal subtidal) predominantly open Knysna temporarily closed Klein Brak estuaries South Africa. Cores endangered seagrass, Zostera capensis , were transplanted two experimental repeats per ecotype size along transects to investigate survival plants post‐transplant. No significant differences observed among sizes, patterns, or Estuary, but cores compact pattern had better rates Estuary. Holes left by smallest donor sites recovered faster sediment deposition compared larger holes. Our demonstrated that Africa is challenging due limited suitable habitats strong environmental variability estuarine ecosystems. It careful consideration, including genomic diversity structure, well ecological similarity between recipient populations must be made each site when assessing its potential. Effective “no‐take bait zones” upstream catchment management will protecting potential meadows.

Language: Английский

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Assisting recolonization of near‐shore seagrasses

Restoration Ecology, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 7, 2025

Natural recolonization of seagrasses may take decades after disturbances and is particularly challenging in near‐shore environments, where sediment mobility inhibits seagrass establishment. We assisted fifteen 4x10 m unvegetated experimental plots a Mexican Caribbean fringe the had died due to massive inundations holopelagic Sargassum species, containment barrier was placed avoid future inundations. The applied treatments were: artificial substrate (AS: 90 belowground, artificial, biodegradable, 15x15 cm‐sized substrates, cut from 0.91 x 0.45m Biodegradable EcoSystem Engineering sheet), transplant (TR: cores, 4.5 cm diameter, with Halodule wrightii ), control (C: no manipulation), each five replicates. After 6 months, 63% H. transplants survived, presenting mean rhizome extension 7.6 cm, natural surrounding patches started colonize plots. approximately 8 AS TR already showed higher light conditions lower fluctuations levels than controls. 14 reached (± SE) density (respectively, 4024 ± 620 3484 360 shoots/m 2 ) cover (60.3 3.85 53.7 2.84 %), compared (2043 381 , 35.3 5.7 % cover). Higher likely favored establishment Thalassia testudinum seedlings, an average 2.07 0.15) 1.87 0.18) seedlings plots, respectively, 0.48 0.23) Both techniques accelerated recolonization, but substrates required less effort avoided harvesting donor meadows.

Language: Английский

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Restoring Halodule uninervis: evaluating planting methods and biodiversity

Restoration Ecology, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 4, 2025

Seagrass provides a crucial habitat for numerous marine species and serves as vital food source endangered species, like dugongs. While extensive research on restoration has been conducted certain temperate slow‐growing climax seagrass limited attention given to tropical pioneer species. This study aimed assess compare two methods the Halodule uninervis evaluate their potential biodiversity recovery after planting. We field experiment at subtropical Inhaca Island, southern Mozambique, testing efficiency of planting (plugs single shoots) densities (~100 ~300 shoots/m 2 ). monitored shoot density in sites 16 months, benthic macrofauna 12 months. Results demonstrated that could grow all combinations both sites. Specifically, method high‐density treatment proved most effective, resulting approximately 1000 within year. Faunal densities, primarily dominated by polychaetes followed malacostraca, bivalves, gastropods, indicated rapid colonization planted areas, especially treatments. Our findings suggest restoring H. is feasible using tested methods. particularly significant because preferred dugong source, its decline due anthropogenic activities be reversed through efforts. Nonetheless, conserving existing should primary focus, approaches employed valuable tool managing coastal areas.

Language: Английский

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Coastal community’s perceptions on the role of seagrass ecosystems for coastal protection and implications for management

Ocean & Coastal Management, Journal Year: 2023, Volume and Issue: 244, P. 106811 - 106811

Published: Sept. 1, 2023

Seagrass meadows provide important ecosystem services to coastal communities, which include ecosystem-based adaptations for protection; however, globally seagrasses are among the least conserved marine ecosystems. In order develop and accurate efficient decision-making processes conservation actions, an understanding of importance people's livelihoods wellbeing is key. Using social research methods, such as Nominal Group Technique, Key Informant Interviews household surveys, this study explored association between seagrass perceptions communities on socio-ecological values including in Maputo Inhambane Bays, Mozambique. Fishermen identified support fisheries production crucial provided by communities. Respondents (93%) perceived that erosion occurring region it has accelerated last 20 years due more frequent floods following cyclones. addition, development (34.9%) together with destructive fishing practices (31.3%) were stated main anthropogenic causes diminish. The (76.3%) proposed restoration first measure prevent erosion. respondents also regulatory being central their economic demonstrated (92%) a desire participate region. This found high level awareness local concerning function meadows. provides strong foundation effective management measures ensure sustainable solutions build resilience stronger against climate change.

Language: Английский

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Less Is More: Seagrass Restoration Success Using Less Vegetation per Area

Sustainability, Journal Year: 2023, Volume and Issue: 15(17), P. 12937 - 12937

Published: Aug. 28, 2023

Seagrass restoration in open coast environments presents unique challenges. Traditional sod transplant designs, though relatively successful these environments, are impractical for large-scale due to high biomass requirements. Here, we develop the checkers design, which aims optimise usage of by transplanting fewer sods a checkerboard pattern. We established six plots (9 m2 each) each species (Zostera marina and Zostera noltei), with 25 plot. The area, percent cover, density, leaf length were measured at 1, 6, 12 months. located on seaward end design vanished over winter, suggesting location-dependent survival influenced winter storms. Nevertheless, both exhibited increased percentages vegetated area after one year, variations between species. Z. noltei showed slower expansion but greater resilience while displayed higher density cover first 6 months experienced loss during winter. Despite differences, survived areas indicating viability promise method restoration. However, careful consideration location or storm-mitigating measures is essential implementation this method.

Language: Английский

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Wave, light, and dissolved oxygen exposures drive novel coastal eelgrass (Zostera pacifica) transplant performance

Frontiers in Marine Science, Journal Year: 2024, Volume and Issue: 11

Published: Feb. 9, 2024

The high ecological and economic value of seagrass has been long recognized, with these foundational habitats providing myriad ecosystem services. Yet through cumulative anthropogenic impacts, seagrasses are exhibiting extensive declines globally. A litany studies active restoration trials have demonstrated practical methodologies to restore effectively return critical habitat functions degraded coastal zone systems worldwide. Seagrass loss along the U.S. West Coast precipitated decades protection, conservation, efforts. Yet, mitigation transplanting efforts prioritized Zostera marina (narrow-leaved eelgrass) in shallow, protected environments, while a dearth information is available on species inhabiting offshore islands exposed mainland coasts. In this study, we conducted novel transplant pacifica , wide-leaved found depths 7 – 20 m coast California. Transplants were at three geographically distinct sites Santa Monica Bay, coupled continuous monitoring biophysical parameters insight into physical drivers donor sites. Utilizing situ data, environmental thresholds adapted from literature for Z. performed exposure analyses evaluate factors influencing performance. Exceedances threshold values parameters, specifically, wave near-bed flow speeds ( H rms > 0.59 U 0.1 s -1 ), photosynthetically radiation (< 3 5 mol -2 day ) dissolved oxygen mg O 2 L impacted survivorship. These results suggest persist biophysically dynamic conditions sensitive exceedances thresholds, underlining importance pre-transplant site-selection processes species. data represent first holistic study an coast, which provides view baseline envelopes within existing habitat, further, may serve as model investigating scalable open temperate regions.

Language: Английский

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Coastal communities' perceptions on coastal erosion and the protective role of seagrass meadows in Dar es Salaam, Tanzania

Marine Policy, Journal Year: 2024, Volume and Issue: 171, P. 106428 - 106428

Published: Oct. 16, 2024

Language: Английский

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