Simulated green turtle grazing affects benthic infauna abundance and community composition but not diversity in a Thalassia testudinum seagrass meadow

Johnson, R. A.; Hanes, Kathleen M.; Bolten, Alan B.; Bjorndal, Karen A.

doi:10.1016/j.jembe.2019.151266

Cited by 10 publications

(5 citation statements)

References 35 publications

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“…However, it should be taken into account that the ecosystem services evaluated (and the loss or gain under different treatments) are based on studies that measures in ecosystems with low presence of megafauna (both sharks and sea turtles) and contradicting effects are found. Examples of contradicting effects include some studies that have documented loss of ecosystem services due to increased grazing by green turtles in seagrass ecosystems (James et al, 2020 ) while others have found no effect or improvement to ecosystem services in grazed systems, including nutrient cycling, macroalgal diversity, sediment stabilization and erosion, and carbon sequestration (Christianen et al, 2012 ; Johnson et al, 2017 , 2019 , 2020 ; Molina Hernández & van Tussenbroek, 2014 ).…”

Section: Discussionmentioning

confidence: 99%

Seagrass ecosystem multifunctionality under the rise of a flagship marine megaherbivore

Christianen

Smulders

Vonk

et al. 2022

Global Change Biology

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Large grazers (megaherbivores) have a profound impact on ecosystem functioning. However, how ecosystem multifunctionality is affected by changes in megaherbivore populations remains poorly understood. Understanding the total impact on ecosystem multifunctionality requires an integrative ecosystem approach, which is especially challenging to obtain in marine systems. We assessed the effects of experimentally simulated grazing intensity scenarios on ecosystem functions and multifunctionality in a tropical Caribbean seagrass ecosystem. As a model, we selected a key marine megaherbivore, the green turtle, whose ecological role is rapidly unfolding in numerous foraging areas where populations are recovering through conservation after centuries of decline, with an increase in recorded overgrazing episodes. To quantify the effects, we employed a novel integrated index of seagrass ecosystem multifunctionality based upon multiple, well-recognized measures of seagrass ecosystem functions that reflect ecosystem services. Experiments revealed that intermediate turtle

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Section: Discussionmentioning

confidence: 99%

Seagrass ecosystem multifunctionality under the rise of a flagship marine megaherbivore

Christianen

Smulders

Vonk

et al. 2022

Global Change Biology

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“…This difference is probably due to the relatively low NPP of Bahamian seagrass meadows. Grazing may also be an important factor, through herbivores such as green turtles and conch 43,49 . Although longterm protection offered to tiger sharks in The Bahamas has likely helped to keep seagrass habitats from overgrazing through the top-down control of grazers 14 , our findings revealed a simultaneous decline of seagrass-derived C org in sediments after the 1980s, indicating disturbance of seagrasses around The Exumas.…”

Section: Discussionmentioning

confidence: 99%

Substantial blue carbon sequestration in the world’s largest seagrass meadow

Fu,

Frappi,

Havlik

et al. 2023

Commun Earth Environ

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Seagrass meadows are important sinks for organic carbon and provide co-benefits. However, data on the organic carbon stock in seagrass sediments are scarce for many regions, particularly The Bahamas, which accounts for up to 40.7% of the documented global seagrass area, limiting formulation of blue carbon strategies. Here, we sampled 10 seagrass meadows across an extensive island chain in The Bahamas. We estimate that Bahamas seagrass meadows store 0.42–0.59 Pg organic carbon in the top-meter sediments with an accumulation rate of 2.1–2.9 Tg annually, representing a substantial global blue carbon hotspot. Autochthonous organic carbon in sediments decreased from ~1980 onwards, with concomitant increases in cyanobacterial and mangrove contributions, suggesting disturbance of seagrass ecosystems, likely caused by tourism and maritime traffic activities. This study provides seagrass blue carbon data from a vast, understudied region and contributes to improving climate action for The Bahamas and the Greater Caribbean region.

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“…Structurally complex seagrass areas support higher populations of fish (Jones et al 2021), and excessive turtle grazing, through a flow effect, undermines this habitat provisioning (Scott et al ). It is well known that highly grazed seagrass areas lose important fauna, including fisheries species (Johnson et al 2020, Inoue et al 2021. Therefore, the loss or collapse of seagrass structure poses significant well-being risks for fisherfolk who depend on seagrass and associated species as a source of food security or livelihoods through further flow effects (Arthur et al 2013).…”

Section: Unintended Consequences Of Charismatic Megafauna Conservationmentioning

confidence: 99%

Unintended consequences of sustainable development initiatives: risks and opportunities in seagrass social-ecological systems

Jones¹,

Cullen-Unsworth²,

Torre‐Castro³

et al. 2022

E&S

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Conserving biodiversity with a growing human population is a key sustainability challenge. Consequently, a vast number of development initiatives across the globe have been designed to combine social, economic, and environmental perspectives. For the most part, the development community is well acquainted with the negative experiences and unintended consequences that some projects have or may bring. However, in tropical coastal ecosystems, this aspect is not completely acknowledged, studied, or understood. Here, we use tropical seagrass meadows as a model social-ecological system to investigate how sustainable development initiatives result in unintended consequences with both positive and negative outcomes for environment and society. We analyze the initiatives and their effects in terms of a typology encompassing "flow", "addition", and "deletion" effects and investigate them across four types of sustainable development initiatives that occur within tropical coastal environments: (1) megafauna conservation, (2) alternative livelihood programs, (3) mosquito net malaria prophylaxis, and (4) marine protected areas. Using these four initiatives as examples, we show that sustainable development initiatives can produce unintended effects with major consequences. Further, we illustrate how not assessing such effects may ultimately undermine the initial goals of the sustainable development intervention. Our study suggests that acknowledging unintended effects and transitioning them so that they become sustainable is more effective than ignoring effects or viewing them as trade-offs. We strongly stress the need for an a priori process in which positive effects, negative effects, and potential uncertainties and surprises are considered when planning the development intervention, and we argue for greater social-ecological monitoring of initiatives. As such, this contribution links to contemporary approaches dealing with the sustainability of natural resources and social-ecological systems and bridges with the importance of development initiatives in the context of the United Nations Sustainable Development Goals.

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Simulated green turtle grazing affects benthic infauna abundance and community composition but not diversity in a Thalassia testudinum seagrass meadow

Cited by 10 publications

References 35 publications

Seagrass ecosystem multifunctionality under the rise of a flagship marine megaherbivore

Seagrass ecosystem multifunctionality under the rise of a flagship marine megaherbivore

Substantial blue carbon sequestration in the world’s largest seagrass meadow

Unintended consequences of sustainable development initiatives: risks and opportunities in seagrass social-ecological systems

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