Survival and re-establishment of vegetative fragments of eelgrass (Zostera marina)

1996 ◽  
Vol 74 (10) ◽  
pp. 1584-1590 ◽  
Author(s):  
Patrick J. Ewanchuk ◽  
Susan L. Williams
Keyword(s):  
Population Growth ◽  
Water Column ◽  
Asexual Reproduction ◽  
Aquatic Plants ◽  
Zostera Marina ◽  
San Diego ◽  
Potential Contribution ◽  
Mission Bay ◽  
Survival And Growth ◽  
Eelgrass Beds

Vegetative fragmentation of clonal aquatic plants is considered a form of asexual reproduction. Although vegetative fragmentation of eelgrass (Zostera marina L.) is considered a mode of asexual reproduction and dispersal, no data exist to evaluate the potential contribution of fragments (rhizomes with meristems and green leaf shoots) to eelgrass populations. We estimated (i) the size of the fragment population relative to the size of adjacent eelgrass populations, and (ii) the potential for fragments to re-establish in eelgrass beds in Mission Bay, San Diego, Calif. We surveyed the abundance of fragments on adjacent beaches and determined the survival and growth of detached fragments and of fragments re-established in eelgrass beds after varying time spent in the water column. Although vegetative fragments occurred throughout the year, but mostly in winter, they represented a loss of <4% of the leaf shoots in adjacent eelgrass populations. Only 60% of the fragments survived in the water column after 6 weeks, and growth and survivorship of re-established fragments declined with time spent in the water column. Thus, fragmentation represents a small net loss to the eelgrass beds studied and is not a common recruitment mechanism. This result does not support the hypothesis that asexual reproduction in the form of vegetative fragments contributes to eelgrass population growth. Because successful re-establishment is improbable, vegetative fragments also are not likely to contribute substantially to eelgrass dispersal, at least in Mission Bay. Keywords: eelgrass, asexual reproduction, clone fragmentation, Zostera marina.

scholarly journals Variation of carbon contents in eelgrass ( Zostera marina ) sediments implied from depth profiles

2019 ◽  
Vol 15 (6) ◽  
pp. 20180831 ◽  
Author(s):  
Theodor Kindeberg ◽  
Emilia Röhr ◽  
Per-Olav Moksnes ◽  
Christoffer Boström ◽  
Marianne Holmer
Keyword(s):  
Organic Carbon ◽  
Zostera Marina ◽  
Large Scale ◽  
Environmental Changes ◽  
Sediment Cores ◽  
Depth Profiles ◽  
Seagrass Meadows ◽  
Spatio Temporal ◽  
Organic Carbon Storage ◽  
Eelgrass Beds

Seagrass meadows are able to store significant amounts of organic carbon in their underlying sediment, but global estimates are uncertain partly owing to spatio-temporal heterogeneity between and within areas and species. In order to provide robust estimates, there is a need to better understand the fate of, and mechanisms behind, organic carbon storage. In this observational study, we analyse a suite of biotic and abiotic parameters in sediment cores from 47 different eelgrass ( Zostera marina ) beds spanning the distributional range of the Northern Hemisphere. Depth profiles of particulate organic carbon (POC) revealed three patterns of vertical distribution where POC either increased, decreased or showed no pattern with sediment depth. These categories exhibited distinct profiles of δ 13 C and C:N ratios, where high POC profiles had a proportionally larger storage of eelgrass-derived material whereas low POC profiles were dominated by phytoplanktonic and macroalgal material. However, high POC did not always translate into high carbon density. Nevertheless, this large-scale dataset provides evidence that the variability in organic matter source in response to natural and anthropogenic environmental changes affects the potential role of eelgrass beds as POC sinks, particularly where eelgrass decline is observed.

scholarly journals Disruption of essential habitat by a coastal invader: new evidence of the effects of green crabs on eelgrass beds

2011 ◽  
Vol 68 (9) ◽  
pp. 1852-1856 ◽  
Author(s):  
Andrey Malyshev ◽  
Pedro A. Quijón
Keyword(s):  
Invasive Species ◽  
Zostera Marina ◽  
Laboratory Experiments ◽  
Carcinus Maenas ◽  
Green Crab ◽  
Atlantic Canada ◽  
Marine Science ◽  
Eelgrass Beds ◽  
New Evidence

Abstract Malyshev, A., and Quijón, P. A. 2011. Disruption of essential habitat by a coastal invader: new evidence of the effects of green crabs on eelgrass beds. – ICES Journal of Marine Science, 68: 1852–1856. Eelgrass (Zostera marina) beds have been declining in Atlantic Canada and elsewhere, partly as a result of sediment disruption and direct feeding/cutting of basal meristems by the green crab (Carcinus maenas). Green crabs are detrimental to eelgrass beds, and field and laboratory experiments have confirmed that the deleterious role of this invasive species is mediated by at least two mechanisms, depending on the size/age of the crabs: uprooting by adults and grazing by juveniles. Eelgrass uprooting and grazing by green crabs are likely to contribute to further declines or a lack of recovery of eelgrass beds.

scholarly journals AQUATIC PLANTS OF SAN DIEGO

Science ◽  
1885 ◽  
Vol ns-5 (121) ◽  
pp. 441-441
Author(s):  
C. R. Orcutt
Keyword(s):  
Aquatic Plants ◽  
San Diego

Interdisciplinary approaches for the management of existing and emerging human - wildlife conflicts

2010 ◽  
Vol 37 (8) ◽  
pp. 623 ◽  
Author(s):  
Piran C. L. White ◽  
Alastair I. Ward
Keyword(s):  
Decision Making ◽  
Population Growth ◽  
Human Population ◽  
Interdisciplinary Approach ◽  
Evidence Base ◽  
Data Availability ◽  
Potential Contribution ◽  
Human Population Growth ◽  
Intervention Measures ◽  
Interdisciplinary Approaches

Human–wildlife conflicts are increasing throughout the world, principally due to a combination of human population growth, increased pressure on land and natural resources and climate change. Many human–wildlife conflicts stem from differences in objectives between various stakeholder groups, especially where the wildlife in question is a resource that can be exploited for economic or cultural benefit, or where the conservation of wildlife is at odds with human population growth or development pressure. Conflicts can be exacerbated by an incomplete understanding of their causes and/or inappropriate intervention measures. Many traditional forms of intervention are also subject to increasing scrutiny and criticism from society. Here, we highlight the potential strategic benefits that can be made by an interdisciplinary approach to human–wildlife conflict situations, by integrating knowledge and understanding across the natural and social sciences. We also stress the potential tactical benefits from combining new approaches to management with more traditional ones. We emphasise the potential contribution of more recent developments in decision-making under conditions of limited data availability and uncertainty. Finally, we recommend that monitoring should play a more prominent role, both in assessing the role of stakeholder engagement in participatory decision-making and in contributing to the evidence base that will allow competing hypotheses about specific systems to be evaluated in an iterative manner.

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