Depauperate seed banks in urban tropical seagrass meadows

2020 ◽  
Vol 71 (8) ◽  
pp. 935
Author(s):  
Glendon Hong Ming Ong ◽  
Samantha Lai ◽  
Siti Maryam Yaakub ◽  
Peter Todd
Keyword(s):  
Seed Bank ◽  
Large Scale ◽  
Seed Viability ◽  
Seed Banks ◽  
Dormant Seed ◽  
Seagrass Meadows ◽  
Halophila Ovalis ◽  
The Status ◽  
Cymodocea Rotundata

Seagrasses need to be resilient if they are to persist in the long term. Being able to build up a dormant seed bank in sediments is a key strategy that some species employ to regenerate from large-scale degradation. Much of the research on seed banks has focussed on temperate species, and little is known regarding the status of seed banks in tropical meadows. In the present study, we examined the seed bank status of three common seagrass species at six sites in Singapore and attempted to identify potential drivers of seed abundance. Our results indicated depauperate seed banks with few species setting viable seed and low seed densities. Halophila ovalis seeds were found at four sites and Halodule uninervis seeds at two sites, but Cymodocea rotundata seeds were absent from all six sites. Whereas H. ovalis seed viability ranged from 20% to 68.8%, none of the H. uninervis seeds was viable. Halophila ovalis seed densities (33–334m–2) were much higher than those of H. uninervis (9–21m–2). Of the variables examined, only H. ovalis cover was positively correlated with the number of seeds. Our study has highlighted the vulnerability of seagrass meadows in Singapore’s urban waters to future disturbances.

Seagrass seed bank spatial structure and function following a large-scale decline

2021 ◽  
Vol 665 ◽  
pp. 75-87
Author(s):  
JC Jarvis ◽  
SA McKenna ◽  
MA Rahseed
Keyword(s):  
Spatial Structure ◽  
Water Depth ◽  
Seed Bank ◽  
Large Scale ◽  
Halophila Ovalis ◽  
World Heritage Area ◽  
Species Specific ◽  
And Function ◽  
Heritage Area

We examined the spatial structure (distribution, density) and function (viability) of the seagrass sediment seed bank, the storage of viable propagules (e.g. seeds, tubers, diaspores) in the sediment over time,in the northern Great Barrier Reef World Heritage Area in Cairns, Queensland, following a large-scale decline in seagrass area. A spatially explicit seagrass seed bank analysis was paired with a long-term annual assessment of seagrass distribution to assess seed bank spatial patterns and their relationship with the recovery and presence of seagrass, and water depth. Four years post-decline, the seed bank contained Zostera muelleri, Halodule uninervis, Halophila ovalis and Cymodocea serrulata seeds. Seed banks reflected adjacent meadow community composition; however, the density of seeds for all recorded species was significantly lower than analogous seagrass populations, indicating a reduction in the capacity for recovery from the seed bank. A spatial structure existed in both the total (viable + non-viable) and viable seed bank, and distance between seed clusters ranged from 50-550 m depending on species and seed type. Observed patterns in clustering may be explained by variation in water depth and the past distribution of seagrass in these meadows. These results demonstrate that the distribution of seagrass seeds within the seed bank, which directly influences the natural recovery of seagrass communities, is not uniform across species and may result in patchy recovery of the meadows. Therefore, the resilience provided by the seed bank in seagrass communities should not be viewed as a static level of insurance for the entire meadow, but rather as dynamic and species-specific, with variability over both space and time.

scholarly journals Estimation of Seed Bank and Seed Viability of the Gulf of Saint Lawrence Aster, Symphyotrichum laurentianum, (Fernald) Nesom

2004 ◽  
Vol 118 (1) ◽  
pp. 105 ◽  
Author(s):  
Joni F. Kemp ◽  
Christian R. Lacroix
Keyword(s):  
Seed Bank ◽  
Prince Edward Island ◽  
Seed Viability ◽  
Management Plan ◽  
Seed Banks ◽  
The Family ◽  
The Status ◽  
Viable Population ◽  
Tetrazolium Staining ◽  
Persistent Seed Bank

The Gulf of St. Lawrence Aster, Symphyotrichum laurentianum, is a member of the family Asteraceae and is listed as “threatened” by COSEWIC (Committee on the Status of Endangered Wildlife in Canada). This rare and vulnerable halophyte grows in only a few locations in New Brunswick, Prince Edward Island, and the Magdalen Islands, Quebec. As an annual, S. laurentianum relies exclusively on its seeds to survive to the next generation. The goal of this study was to estimate the quantity of viable S. laurentianum seeds in the persistent and transient seed banks at selected sites in Prince Edward Island. Overall, the number of seeds in the transient and persistent seed banks is low. The greatest concentration of seeds was found near the surface of the soil. In addition, only a small proportion of those seeds tested positive for viability based on Tetrazolium staining. Of the seeds in the persistent and transient seed banks combined, 53% were viable whereas only 2% of the seeds in the persistent seed bank were viable. Population surveys were also completed at the five known sites (both extinct and extant) in Prince Edward Island National Park. All sites showed signs of decline based on population estimates dating back to 1993. The Covehead Pond site showed the greatest decline: from 250-300 individuals in 1993 to only 10 individuals in 2002. The population at Dune Slack also showed a dramatic decrease from approximately 65 000 in 1999, to 2 200 individuals in 2002. Monitoring of this plant and the development of a management plan for the species are critical to its survival.

scholarly journals The status of Indonesia’s seagrass meadows

2018 ◽  
Author(s):  
OCTO
Keyword(s):  
Human Activities ◽  
Large Scale ◽  
Blue Carbon ◽  
Coastal Development ◽  
Seagrass Meadows ◽  
The Status ◽  
Monitoring Effort

Indonesia stores 2% of the world’s blue carbon in its seagrass meadows, which are under threat from human activities like coastal development. Without a long-term, large-scale monitoring effort, the continual decline and hopeful recovery of this vital ecosystem will be very difficult to track.

High seed viability recorded in an endangered endemic species, 'Isoplexis isabelliana' (Scrophulariaceae), after more than 30 years of storage in a conservation seed bank

2021 ◽  
Vol 42 ◽  
pp. e69341
Author(s):  
Miguel Ángel González Pérez ◽  
Nereida Cabrera-García ◽  
Isabel Cayon-Fernández
Keyword(s):  
Seed Bank ◽  
Germination Rate ◽  
Genetic Material ◽  
Natural Populations ◽  
Seed Viability ◽  
Seed Storage ◽  
Botanical Garden ◽  
Storage Conditions ◽  
Seed Banks ◽  
Ex Situ

Conservation seed banks are essential for ex-situ conservation of genetic biodiversity. These institutions are especially relevant for threatened species and play a vital role in their conservation by preserving genetic material. However, samples deposited in the seed banks must germinate when necessary to use them (i.e., recovery plans, etc.). This study uses four accessions of the endemic endangered species from Gran Canaria Island (Canary Islands), Isoplexis isabelliana (Webb & Berthel.) Masf. (Scrophulariaceae). Germination tests were carried out to measure seed viability through time and the possible impact of seed storage on their viability. These accessions have been kept in the seed bank for four months to thirty years under different storage conditions. Germination results differed for seeds after 45 days of exposition using 16 hours light and 8 hours darkness at 17 °C. Accessions kept in the seed bank, independently of storage, showed a high germination percentage (89%). Whereas the accessions with rough storage conditions showed a 0% germination rate. The results highlighted the good state of conservation of the material deposited in the Seed Bank of the Botanical Garden "Viera y Clavijo" and the reliability of the temperature and humidity conditions in which the seeds of I. isabelliana have been stored. We consider these results as momentous since several natural populations of I. isabelliana has been affected by the last forest fire on the island.

Mapping seagrass cost-effectively in the Coral Triangle: Sabah, Malaysia as a case study

2015 ◽  
Vol 21 (2) ◽  
pp. 113 ◽  
Author(s):  
Leela Rajamani ◽  
Helene Marsh
Keyword(s):  
Cost Effective ◽  
Human Populations ◽  
Coral Triangle ◽  
Thalassia Hemprichii ◽  
Seagrass Meadows ◽  
Green Turtles ◽  
Halophila Ovalis ◽  
Seagrass Mapping ◽  
Cymodocea Rotundata ◽  
Syringodium Isoetifolium

Knowledge of the distribution and relative abundance of seagrass communities in the Coral Triangle is limited, despite their global significance and the vital ecosystem services they perform for local human populations, threatened species such as dugongs and green turtles, as well as the role of being a globally significant carbon stock. To address this gap and investigate cost-effective methods in data-poor regions, we conducted seagrass mapping near two islands off the coast of Sabah in Malaysia: Banggi Island (7°15′N, 117°12′E) and Mantanani Island (6°43′N, 116°21′E). We used a staged approach that included: (1) interview surveys, (2) manta tow and spot surveys, and (3) comprehensive transect surveys. Approximately 415 ha and 112 ha of seagrass meadows were mapped off Banggi Island and Mantanani Island respectively. We found 10 species of seagrasses from two families: Halophila ovalis, Halodule uninervis (broad and thin leaf varieties), Thalassia hemprichii, Cymodocea rotundata, Halophila decipiens, Halophila spinulosa, Cymodocea serrulata, Syringodium isoetifolium, Enhalus acoroides and Halophila sp. nov. Our methodology proved cost-effective and the resultant information should be relevant to conservation planners.

scholarly journals Rangeland Recovery Potential: Soil Seed Content and Seed Viability

1990 ◽  
Vol 14 ◽  
pp. 63-65
Author(s):  
Jack Butler ◽  
Kara Paintner
Keyword(s):  
Seed Bank ◽  
Seed Viability ◽  
Seed Banks ◽  
Vegetation Changes ◽  
Viable Seed ◽  
Recovery Potential ◽  
Potential Source ◽  
Seed Content ◽  
Recreation Area ◽  
Composition Changes

In most plant communities, soil contains a seed bank (population of dormant seeds), (Harper 1977), which provides a partial record of past and present vegetation (Major and Pyott 1966, Johnson and Anderson 1986). Seed banks are continuously rejuvenated by a "seed rain", from vegetation located on- and off-site. If existing communities are disturbed or destroyed, the seed bank provides a potential source of propagules during succession (Egler 1954, Connell and Slatyer 1977). Consequently, seed banks may serve as an index in predicting what vegetation changes might occur if environmental conditions are favorable for germination (Harper 1977). The objectives of this study are to 1. evaluate the viable seed bank within grazed and relict pinyon-juniper and blackbrush/Indian ricegrass communities in Glen Canyon National Recreation Area (GCNRA), 2. assess the ability of these communities to recover following a disturbance, using their respective seed banks as indicators of recovery potential, and 3. address the suitability of using seed banks to monitor and predict community level composition changes in response to various intensities of grazing.

scholarly journals Evolution with a seed bank: the population genetic consequences of microbial dormancy

2017 ◽  
Author(s):  
WR Shoemaker ◽  
JT Lennon
Keyword(s):  
Seed Bank ◽  
Population Genetic ◽  
Evolutionary Dynamics ◽  
Phenotypic Diversity ◽  
Seed Banks ◽  
Hedging Strategy ◽  
Term Survival ◽  
Evolutionary Forces ◽  
Growth And Reproduction

ABSTRACTDormancy is a bet-hedging strategy that allows organisms to persist through conditions that are sub-optimal for growth and reproduction by entering a reversible state of reduced metabolic activity. Dormancy allows a population to maintain a reservoir of genetic and phenotypic diversity (i.e., a seed bank) that can contribute to the long-term survival of a population. This strategy can be potentially adaptive and has long been of interest to ecologists and evolutionary biologists. However, comparatively little is known about how dormancy influences the fundamental evolutionary forces of genetic drift, mutation, selection, recombination, and gene flow. Here, we investigate how seed banks affect the processes underpinning evolution by reviewing existing theory, implementing novel simulations, and determining how and when dormancy can influence evolution as a population genetic process. We extend our analysis to examine how seed banks can alter macroevolutionary processes, including rates of speciation and extinction. Through the lens of population genetic theory, we can understand the extent that seed banks influence microbial evolutionary dynamics.

scholarly journals Community Structure of Seagrass Meadows In Mantehage Island Waters, North Sulawesi

2014 ◽  
Vol 1 (4) ◽  
pp. 177
Author(s):  
Simon I Patty ◽  
Husen Rifai
Keyword(s):  
Diversity Index ◽  
Seagrass Species ◽  
Thalassia Hemprichii ◽  
Seagrass Meadows ◽  
North Sulawesi ◽  
Halophila Ovalis ◽  
Cymodocea Rotundata ◽  
Syringodium Isoetifolium ◽  
Species Composition And Distribution ◽  
Thalassodendron Ciliatum

Research on the structure of seagrass communities in the waters of the island Mantehage was conducted in September 2010. The purpose of this study is to collect data and information on the structure of seagrass communities. Observations includes the identification seagrass species, measuring the number of individual/stand, cover percentage of each type/species on the transect. 6 types of seagrass found, i.e. Enhalus acoroides, Halophila ovalis, Thalassia hemprichii, Thalassodendron ciliatum, Cymodocea rotundata and Syringodium isoetifolium. Seagrass species composition and distribution varies at each location and is dominated by the presence of Thalassia hemprichii (48.14%) with coverage percentage ranges between 15.91% to 35.11%. Diversity index values ranged from 0.79 to 1.69 ; evenness index between 0.57 to 0.94 and the index of dominance between 0.20 to 0.56. In conclusion, the condition of seagrass meadows in Mantehage island is relatively good and can support marine life adequately.Keywords : Structure communities, seagrass, Mantehage Island

scholarly journals Rangeland Recovery Potential: Soil Seed Content and Seed Viability

1991 ◽  
Vol 15 ◽  
pp. 130-135
Author(s):  
Jack Butler ◽  
Kara Paintner
Keyword(s):  
Seed Bank ◽  
Seed Viability ◽  
Seed Banks ◽  
Community Level ◽  
Viable Seed ◽  
Recovery Potential ◽  
Seed Content ◽  
Composition Changes

The objectives of this project are to 1) evaluate the viable seed bank within grazed and relict pinyon­juniper and blackbrush/lndian ricegrass communities, 2) assess the ability of these communities to recover following a disturbance using their respective seed banks as indicators of recovery potential, and 3) address the suitability of using seed banks to monitor and predict community level composition changes in response to various intensities of grazing.

scholarly journals Effects of Waves and Sediment Disturbance on Seed Bank Persistence at Tidal Flats

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhenchang Zhu ◽  
Tjeerd J. Bouma ◽  
Qin Zhu ◽  
Yanpeng Cai ◽  
Zhifeng Yang
Keyword(s):  
Climate Change ◽  
Seed Bank ◽  
Large Scale ◽  
Environmental Changes ◽  
Tidal Flats ◽  
Coastal Vegetation ◽  
Climate Change Effects ◽  
Sediment Disturbance ◽  
Seed Bank Dynamics

Coastal wetlands such as salt marshes have been increasingly valued for their capacity to buffer global climate change effects, yet their long-term persistence is threatened by environmental changes. Whereas, previous studies largely focused on lateral erosion risk induced by stressors like sea level rise, it remains poorly understood of the response of lateral expansion to changing environments. Seedling establishment is a key process governing lateral marsh expansion as seen in many coastal regions such as Europe and East Asia. Here, we evaluate mechanistically the response of seed bank dynamics to changing physical disturbance at tidal flats, using the globally common coastal foundation plant, cordgrass as a model. We conducted a large-scale field study in an estuary in Northwest Europe, where seed bank dynamics of cordgrass in the tidal flats was determined and linked to in situ hydrodynamics and sediment dynamics. The results revealed that wave disturbance reduced the persistence of seeds on the surface, whereas amplified sediment disturbance lowered the persistence of both surface and buried seeds. Overall, this indicates that increasing storminess and associated sediment variability under climate change threatens seed bank persistence in tidal flats, and hence need urgently be incorporated into models for long-term bio-geomorphological development of vegetated coastal ecosystems. The knowledge gained here provides a basis for more accurate predictions on how climatically driven environmental changes may alter the fitness, resilience and persistence of coastal foundation plants, with significant implications for nature-based solutions with coastal vegetation to mitigate climate change effects.

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