Restoring subtidal marine macrophytes in the Anthropocene: trajectories and future-proofing

2019 ◽  
Vol 70 (7) ◽  
pp. 936 ◽  
Author(s):  
G. Wood ◽  
E. M. Marzinelli ◽  
M. A. Coleman ◽  
A. H. Campbell ◽  
N. S. Santini ◽  
...  

Anthropogenic activities have caused profound changes globally in biodiversity, species interactions and ecosystem functions and services. In terrestrial systems, restoration has emerged as a useful approach to mitigate these changes, and is increasingly recognised as a tool to fortify ecosystems against future disturbances. In marine systems, restoration is also gaining traction as a management tool, but it is still comparatively scant and underdeveloped relative to terrestrial environments. Key coastal habitats, such as seaweed forests and seagrass meadows are showing widespread patterns of decline around the world. As these important ecosystems increasingly become the target of emerging marine restoration campaigns, it is important not only to address current environmental degradation issues, but also to focus on the future. Given the rate at which marine and other environments are changing, and given predicted increases in the frequency and magnitude of multiple stressors, we argue for an urgent need for subtidal marine macrophyte restoration efforts that explicitly incorporate future-proofing in their goals. Here we highlight emerging scientific techniques that can help achieve this, and discuss changes to managerial, political and public frameworks that are needed to support scientific innovation and restoration applications at scale.

2020 ◽  
Vol 2 ◽  
Author(s):  
Olalekan A. Agboola ◽  
Colleen T. Downs ◽  
Gordon O'Brien

The rivers of KwaZulu-Natal, South Africa, are being impacted by various anthropogenic activities that threaten their sustainability. Our study demonstrated how Bayesian networks could be used to conduct an environmental risk assessment of macroinvertebrate biodiversity and their associated ecosystem to assess the overall effects of these anthropogenic stressors in the rivers. We examined the exposure pathways through various habitats in the study area using a conceptual model that linked the sources of stressors through cause-effect pathways. A Bayesian network was constructed to represent the observed complex interactions and overall risk from water quality, flow and habitat stressors. The model outputs and sensitivity analysis showed ecosystem threat and river health (represented by macroinvertebrate assessment index – MIRAI) could have high ecological risks on macroinvertebrate biodiversity and the ecosystem, respectively. The results of our study demonstrated that Bayesian networks can be used to calculate risk for multiple stressors and that they are a powerful tool for informing future strategies for achieving best management practices and policymaking. Apart from the current scenario, which was developed from field data, we also simulated three other scenarios to predict potential risks to our selected endpoints. We further simulated the low and high risks to the endpoints to demonstrate that the Bayesian network can be an effective adaptive management tool for decision making.


2021 ◽  
Vol 8 ◽  
Author(s):  
Alejandro Román ◽  
Antonio Tovar-Sánchez ◽  
Irene Olivé ◽  
Gabriel Navarro

Marine macrophytes constitute one of the most productive ecosystems on the planet, as well as one of the most threatened by anthropogenic activities and climate change. Their monitoring is therefore essential, which has experienced a fast methodological evolution in recent years, from traditional in situ sampling to the use of satellite remote sensing, and subsequently by sensors mounted on unmanned aerial vehicles (UAV). This study aims to advance the monitoring of these ecosystems through the use of a UAV equipped with a 10-band multispectral camera, using different algorithms [i.e., maximum likelihood classifier (MLC), minimum distance classifier (MDC), and spectral angle classifier (SAC)], and using the Bay of Cádiz Natural Park (southern Spain) as a case of study. The results obtained with MLC confirm the suitability of this technique for detecting and differentiating seagrass meadows in a range of 0–2 m depth and the efficiency of this tool for studying and monitoring marine macrophytes in coastal areas. We inferred the existence of a cover of 25452 m2 of Cymodocea nodosa, and macroalgae species such as Caulerpa prolifera, covering 22172 m2 of Santibañez (inner Bay of Cádiz).


2020 ◽  
Author(s):  
Ludovic Pascal ◽  
Gwénaëlle Chaillou ◽  
Pascal Bernatchez ◽  
Christian Nozais ◽  
Philippe Archambault

<p>Seagrass meadows are among the most productive ecosystems in the world: they store a large amount of carbon and host highly diverse macrobenthic communities. They also play a key role in biogeochemistry at the sediment-water interface. The light requirements of seagrasses limit their development to shallow coastal areas where they are facing various natural and anthropogenic disturbances, which has induced a global loss of these ecosystems over the last decades. Nutrient enrichment of coastal waters, resulting from anthropogenic activities is one of the leading causes of this decline. Subpolar seagrass meadows present a strong seasonal dynamic, with a long winter when seagrasses rely on carbon reserves that they build up during the short growing season (limited to two to three months during summer time). Hence, it has been hypothesized that the effects of nutrient enrichment on seagrass ecosystem functioning depend on seasonal dynamics. In this study, we performed a series of mesocosm experiments over a month period to investigate the effects of the timing, duration and intensity of disturbance on macrofauna bioturbation, oxygen and nutrients porewater concentration profiles and benthic fluxes using three levels (including control) of realistic nutrient enrichments at the beginning (June) and at the end (August) of the growing season. In May, effects of intermediate level of nutrient enrichment were only visible on total oxygen uptake by the sediment at day 30 of disturbance while it affected oxygen and nutrients benthic fluxes at day 15 in August. The highest level of nutrient enrichment affected oxygen and nutrients benthic fluxes in May and August. Overall, our results highlight the importance of considering the time (period and duration) in the assessment of the functional consequences of disturbances.</p>


2018 ◽  
Vol 61 (3) ◽  
pp. 305-320 ◽  
Author(s):  
Yi Mei Tan ◽  
Justine E. Saunders ◽  
Siti Maryam Yaakub

AbstractSeagrass habitats provide a range of goods and benefits to coastal communities by supporting ecosystem functioning, food provisioning, and cultural values. However, they are at risk worldwide from anthropogenic activities, climate change impacts and limited resources, which hamper efforts to protect them. Effective conservation planning requires prioritisation of sites based on multiple factors, including their relative value and vulnerability (VU). The current study examines the efficacy of combining two well-established approaches – ecosystem service assessments and habitat VU analyses – to test a method for determining conservation priority for selected seagrass meadows in Southeast Asia. Seven seagrass meadows around Southeast Asia were selected and scored by the authors based on (1) the cumulative contribution of 12 ecosystem services (ES) and the condition of the meadows, (2) VU from 16 anthropogenic threats, which were each ranked against five factors (spatial scale, frequency, functional impact, resistance and recovery time) and (3) the combination of the two approaches to create a single numerical index. Prioritisation of sites differed when meadows were scored solely for the ES they provide, compared to how vulnerable they are to anthropogenic threats. The new combined analysis brought the two metrics together to give conservation priority to sites where management intervention will yield maximum conservation benefits from conservation effort, and resulted in the prioritisation of three sites: Barrang Lompo (Indonesia), Cape Bolinao (Philippines) and Beting Tanjung Kupang (Malaysia). This method is easy to use and does not require great technical expertise. It is also auditable, allowing for clear and transparent understanding of decision-making process.


2010 ◽  
Vol 26 (4) ◽  
pp. 407-414 ◽  
Author(s):  
Harald Beck ◽  
Paporn Thebpanya ◽  
Melissa Filiaggi

Abstract:The concept of ecosystem engineering has catalysed novel approaches and models for non-trophic species interactions and ecosystem functions. Ecosystem engineers physically modify abiotic and biotic environments, thereby creating new habitats that can be colonized by a new suite of species. In the Peruvian Amazonas, we tested whether peccaries (Tayassuidae) function as ecosystem engineers by creating and maintaining wallows. Such wallows could be critical aquatic habitats and breeding sites for anuran species during dry seasons. We compared hydroperiods of 21 peccary wallows and 13 naturally formed ponds across three dry seasons and found that wallows had a consistently higher mean water surface area than ponds. We also examined the pH, dissolved oxygen and temperature, and found no significant differences in these parameters between water bodies. Wallows had a significantly higher density of tadpoles, metamorphs and adult anurans, as well as higher β-diversity and species richness than ponds. This study not only provides the first systematic evidence of the ecosystem engineering processes of peccaries, but also reveals the positive consequences of such for anuran species.


2016 ◽  
Author(s):  
Jan Niklas Macher

Biodiversity loss due to increasing anthropogenic activities is one of the biggest threats to humanity. Understanding the impacts of multiple-stressors on ecosystems and biodiversity is therefore an urgent task. Shore ecosystems are especially valuable, as they harbour a high biodiversity and provide important ecosystems services. Until now, experimental approaches addressing multiple-stressor impacts on these ecosystems have been rare and mostly run with a limited number of replicates and under non-natural conditions. Here, an experimental field mesocosm system that allows studying multiple-stressor impacts on rock pool biodiversity is proposed. The ExMarine mesocosm system is composed of 64 experimental rock pool mesocosms in a fully randomised block design, which allows studying multiple-stressor impacts under highly standardised conditions. Water is taken directly from the sea, allowing biota to immigrate and emigrate freely. Water flow into the mesocosms can be regulated and it is possible to simulate disturbance through waves during high tide. The system can help to understand the impacts of multiple stressors on biodiversity, to monitor ecosystem health and to plan measures preventing the further loss of biodiversity.


Author(s):  
Rohani Ambo-Rappe ◽  
Yayu A. La Nafie ◽  
Syafiuddin ◽  
Steven R. Limbong ◽  
Nenni Asriani ◽  
...  

Abstract. Ambo-Rappe R, La Nafie YA, Syafiuddin, Limbong SR, Asriani N, Handayani NT, Lisdayanti E. 2019. Short Communication: Restoration of seagrass Enhalus acoroides using a combination of generative and vegetative techniques. Biodiversitas 20: 3358-3363. Seagrass areas have been declining in extent worldwide, with associated loss in seagrass ecosystem functions and services. Seagrass restoration is important to mitigate, halt and reverse such declines and their consequences. Generative propagation has benefits in terms of genetic biodiversity, however, survival of seagrass seedlings has often been poor especially in high energy environments. Terrestrial restoration often uses shade trees to protect vulnerable seedlings. This study aimed to evaluate the feasibility of a similar approach in the marine environment, using adult plants to protect seedlings of the tropical seagrass Enhalus acoroides (L.f.) Royle. Enhalus seeds taken from a donor bed were germinated and grown into seedlings, then planted in a location with high hydrodynamic exposure at three different densities (high, medium, and low). Adult Enhalus transplants were co-planted to provide three levels of protection: fifty (high), ten (medium), and none (no protection). Results showed that high-density seedling co-planting with high protection from adult transplants had significantly (p< 0.05) higher six-month survival rate compared to the other treatments. Our results indicate that, even in high energy environments, co-planting seedlings with adult transplants may combine the advantages of generative and vegetative propagation methods, promoting greater short-term effectiveness in terms of seedlings survival and growth in the restored seagrass meadows.


2021 ◽  
Vol 664 ◽  
pp. 103-116
Author(s):  
L Martínez-García ◽  
B Hansson ◽  
J Hollander

Seagrass meadows are one of the most important habitats in coastal regions since they constitute a multifunctional ecosystem providing high productivity and biodiversity. They play a key role in carbon sequestration capacity, mitigation against coastal erosion and as nursery grounds for many marine fish and invertebrates. However, despite these ecosystem functions and services, seagrass meadows are a threatened ecosystem worldwide. In the Baltic Sea, seagrass meadows have declined rapidly, mainly because of eutrophication, anthropogenic activities and climate change. This decline has the potential to erode the genetic variation and genetic structure of the species. In this study, we assessed how genetic variation and genetic differentiation vary among Zostera marina meadows and with a number of environmental characteristics in the county of Scania in southern Sweden. A total of 205 individuals sampled at 12 locations were analysed with 10 polymorphic microsatellite loci. Results showed that in spite of anthropogenic impacts and climate change pressures, locations of Z. marina possessed high genetic variation and weak genetic differentiation, with 3 major genetic clusters. Long-distance dispersal and/or stepping-stone dispersal was found among locations, with higher migration rates within the west coast. Organic matter, salinity and maximum depth appeared to be factors most strongly associated with the genetic structure and morphological variation of Z. marina. These findings contribute significantly in the identification of potential donor sites and the viability of impacted areas to recover from natural recruitment, for the development of effective transplantation measures of Z. marina in the southern Baltic Sea and temperate regions elsewhere.


2021 ◽  
Vol 288 (1962) ◽  
Author(s):  
Amanda Xuereb ◽  
Quentin Rougemont ◽  
Peter Tiffin ◽  
Huijie Xue ◽  
Megan Phifer-Rixey

As climate change threatens species' persistence, predicting the potential for species to adapt to rapidly changing environments is imperative for the development of effective conservation strategies. Eco-evolutionary individual-based models (IBMs) can be useful tools for achieving this objective. We performed a literature review to identify studies that apply these tools in marine systems. Our survey suggested that this is an emerging area of research fuelled in part by developments in modelling frameworks that allow simulation of increasingly complex ecological, genetic and demographic processes. The studies we identified illustrate the promise of this approach and advance our understanding of the capacity for adaptation to outpace climate change. These studies also identify limitations of current models and opportunities for further development. We discuss three main topics that emerged across studies: (i) effects of genetic architecture and non-genetic responses on adaptive potential; (ii) capacity for gene flow to facilitate rapid adaptation; and (iii) impacts of multiple stressors on persistence. Finally, we demonstrate the approach using simple simulations and provide a framework for users to explore eco-evolutionary IBMs as tools for understanding adaptation in changing seas.


2012 ◽  
Vol 9 (2) ◽  
pp. 1529-1555 ◽  
Author(s):  
C. Barrón ◽  
E. T. Apostolaki ◽  
C. M. Duarte

Abstract. Estimates of dissolved organic carbon (DOC) release by marine macrophyte communities (seagrass meadows and macroalgal beds) were obtained experimentally using in situ benthic chambers. The effect of light availability on DOC release by macrophyte communities was examined in two communities both by comparing net DOC release under light and dark, and by examining the response of net DOC release to longer-term (days) experimental shading of the communities. All most 85% of the seagrass communities and almost all of macroalgal communities examined acted as net sources of DOC. There was a weak tendency for higher DOC fluxes under light than under dark conditions in seagrass meadow. There is no relationship between net DOC fluxes and gross primary production (GPP) and net community production (NCP), however, this relationship is positive between net DOC fluxes and community respiration. Net DOC fluxes were not affected by shading of a T. testudinum community in Florida for 5 days, however, shading of a mixed seagrass meadow in the Philippines led to a significant reduction on the net DOC release when shading was maintained for 6 days compared to only 2 days of shading. Based on published and unpublished results we also estimate the global net DOC production by marine macrophytes. The estimated global net DOC flux, and hence export, from marine macrophyte is about 0.197 ± 0.015 Pg C yr−1 or 0.212 ± 0.016 Pg C yr−1 depending if net DOC flux by seagrass meadows was estimated by taking into account the low or high global seagrass area, respectively.


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