scholarly journals The World of Edges in Submerged Vegetated Marine Canopies: From Patch to Canopy Scale

Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2430
Author(s):  
Jordi Colomer ◽  
Teresa Serra

This review describes the world of edges in submerged vegetated marine canopies (seagrasses, saltmarshes, and seaweeds) where an edge is a boundary with a frontal area separating the vegetation from the adjacent non-vegetated zones. Plants within the vegetation are made of flexible elements pronating in the direction of the flow and oscillating back and forth in response to wave forcing. Some of them also occupy the full height within the water body. The analysis focuses on both the canopy- and local-patch scales to acquire knowledge about the hydrodynamics and the biophysical interactions in the structural shallows and deep limits of the canopies as well as on the structural edges of vegetation patches and the edges in the gaps within the canopies. The spatial arrangements of both canopy and patch edges are not only well imposed through the modification of hydrodynamics, but so too through small-scale interactions from internal structural causes and modifications. The continuous fragmentation of coastal marine habitats has reduced their structural complexity, thus making habitat edges a prevalent seascape feature, including in the shallow (or upper) and deep (or lower) limits of the canopies, the patch edges, and the edges in the gaps within the canopies. Canopy patches represent a region of high flow resistance where flow deflects and accelerates above and/or next to the canopy, resulting in an increase in water velocity and turbulence, especially at the edges of the patch. At the edges, energy transfer is found in spectral wave velocities from the longer to shorter wave period components. Likewise, at the edges, the net deposition of sediments decreases over a distance to a certain length, relative to the bare bed, which is associated with a region of vertical updraft and elevated turbulent kinetic energy. The edge effects also relate to the influence that a patch edge can have on determining species composition and predation risk, which is additionally mediated by the effect the edges have on habitat complexity within the vegetated patch. Organism feedback within the edges does not simply follow the canopy and local features and, in fact, the intricate interaction between biogeophysical processes is key in explaining the complexity of coastal submerged canopy landscapes. For example, proximity to patch edges has a greater influence on epifaunal density and community structure than structural complexity or predation do. The extent to which edges reduce predation risk depends on the extent to which they support higher structural complexities compared to patch interiors. The canopies’ shallow limits and their position in the underwater beach profile are mostly limited by light availability, the intensity of the wave action, and the local nearshore hydrodynamics, but they also depend on the local structural conditions at the vegetated side. The deep limits of the canopies, however, mainly depend on the availability of light and research findings support migration both to the deeper and shallower layers. All structural edges face changes caused by increasing nutrient inputs, development of coastal zones and the increasing impact of climate change. A considerable challenge to managing, restoring, and conserving coastal marine ecosystems stems from understanding how the canopies are able to cope with these natural and anthropogenic disturbances.

2021 ◽  
Author(s):  
Yvan Gouzenes ◽  
Anny Cazenave ◽  
Fabien Léger ◽  
Florence Birol ◽  
Marcello Passaro ◽  
...  

<p>Climate-related sea level changes in the world coastal zones result from the superposition of the global mean rise due to ocean warming and land ice melt, regional changes mostly caused by non-uniform ocean thermal expansion and salinity changes, and small-scale coastal processes (e.g., shelf currents, wind & waves changes, fresh water input from rivers, etc.). So far, satellite altimetry has provided global gridded sea level time series up to 10-15 km to the coast only, preventing estimation of sea level changes very close to the coast. In the context of the ESA Climate Change Initiative coastal sea level project, we have developed a complete reprocessing of high-resolution (20 Hz) Jason-1, 2 and 3 altimetry data along the world coastal zones using the ALES (Adaptative Leading Edge Subwaveform) retracker combined with the XTRACK system dedicated to improve geophysical corrections at the coast. Here we present coastal sea level trends over the period 2002-2020 along the whole African continent. Different coastal sea level trend behaviors are observed over the study period. We compare the computed coastal trends in Africa with results we previously obtained in other regions (Mediterranean Sea, Northeastern Europe, north Indian Sea, southeast Asia and Australia).</p>


2021 ◽  
Vol 13 (8) ◽  
pp. 1513
Author(s):  
Dominik Seidel ◽  
Peter Annighöfer ◽  
Christian Ammer ◽  
Martin Ehbrecht ◽  
Katharina Willim ◽  
...  

The structural complexity of the understory layer of forests or shrub layer vegetation in open shrublands affects many ecosystem functions and services provided by these ecosystems. We investigated how the basal area of the overstory layer, annual and seasonal precipitation, annual mean temperature, as well as light availability affect the structural complexity of the understory layer along a gradient from closed forests to open shrubland with only scattered trees. Using terrestrial laser scanning data and the understory complexity index (UCI), we measured the structural complexity of sites across a wide range of precipitation and temperature, also covering a gradient in light availability and basal area. We found significant relationships between the UCI and tree basal area as well as canopy openness. Structural equation models (SEMs) confirmed significant direct effects of seasonal precipitation on the UCI without mediation through basal area or canopy openness. However, annual precipitation and temperature effects on the UCI are mediated through canopy openness and basal area, respectively. Understory complexity is, despite clear dependencies on the available light and overall stand density, significantly and directly driven by climatic parameters, particularly the amount of precipitation during the driest month.


2007 ◽  
Vol 2 (2) ◽  
pp. 229-238
Author(s):  
Scott M. Fitzpatrick ◽  
Jon M. Erlandson ◽  
Atholl Anderson ◽  
Patrick V. Kirch

In a recent ISJ paper, “Island Archaeology: In Search of a New Horizon”, Boomert and Bright (2007) argue that the field of “island archaeology” should be replaced by an “archaeology of maritime identity”. We disagree and counter that although islands share many physical, biological, and cultural similarities with continental coasts, coastal zones also grade uninterruptedly into riverine, lacustrine, and terrestrial landscapes, raising questions about the validity of their concept of the archaeology of maritime identity. In our view, island archaeology (the application of archaeology to island settings), regardless of past biogeographical underpinnings, has made major contributions to understanding the historical ecology, human impacts, and cultural developments of islands around the world. A focus on islands by archaeologists has encouraged scholars to study the history of island and maritime societies within a comparative framework that is useful for breaking out of the often provincial focus on a single island or archipelago.


2021 ◽  
Vol 73 (1) ◽  
Author(s):  
H. Clark Barrett

Psychological research in small-scale societies is crucial for what it stands to tell us about human psychological diversity. However, people in these communities, typically Indigenous communities in the global South, have been underrepresented and sometimes misrepresented in psychological research. Here I discuss the promises and pitfalls of psychological research in these communities, reviewing why they have been of interest to social scientists and how cross-cultural comparisons have been used to test psychological hypotheses. I consider factors that may be undertheorized in our research, such as political and economic marginalization, and how these might influence our data and conclusions. I argue that more just and accurate representation of people from small-scale communities around the world will provide us with a fuller picture of human psychological similarity and diversity, and it will help us to better understand how this diversity is shaped by historical and social processes. Expected final online publication date for the Annual Review of Psychology, Volume 73 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


2019 ◽  
Vol 4 (3) ◽  
pp. 194-207
Author(s):  
PIET GELEYNS

The Hoge Kempen rural industrial transition landscape: a layered landscape of Outstanding Universal Value? Up until the beginning of the 20th century, the eastern part of the Belgian province of Limburg was a sparsely populated and not very productive part of the country. The dominating heathland was maintained with sheep, which were an essential part of a small-scale extensive farming system. This all changed when coal was discovered in 1901. Seven large coalmines were established in a few decades, each one employing thousands of coal-miners. This also meant that entire new garden cities were built, to house the coal-miners and their families. The confrontation between the small-scale traditional land-use and the new large-scale industrial developments defines the landscape up to today. The scale and the force of the turnover are considered unprecedented for Western Europe, which is why it is being presented by Belgium for inclusion in the World Heritage List.


2017 ◽  
Vol 2 (2) ◽  
pp. 155-167
Author(s):  
Deb Cleland

Charting the course: The world of alternative livelihood research brings a heavy history of paternalistic colonial intervention and moralising. In particular, subsistence fishers in South East Asia are cyclical attractors of project funding to help them exit poverty and not ‘further degrade the marine ecosystem’ (Cinner et al. 2011), through leaving their boats behind and embarking on non-oceanic careers. What happens, then, when we turn an autoethnographic eye on the livelihood of the alternative livelihood researcher? What lexicons of lack and luck may we borrow from the fishers in order to ‘render articulate and more systematic those feelings of dissatisfaction’ (Young 2002) of an academic’s life’s work and our work-life? What might we learn from comparing small-scale fishers to small-scale scholars about how to successfully ‘navigate’ the casualised waters of the modern university? Does this unlikely course bring any ideas of ‘possibilities glimmering’ (Young 2002) for ‘exiting’ poverty in Academia?


2021 ◽  
pp. 1-31
Author(s):  
Filippo Osella

Abstract Drawing on ethnographic data collected in China, the United Arab Emirates (UAE), and India, this article explores the life-world and practices of small-scale Indian export agents based in Yiwu, China, the world centre for the export of small commodities. It shows that in a market overdetermined by fast-moving goods, short-term gains, and low margins, export agents have to steer their way between acting with extreme caution or taking risks with their clients and suppliers. These apparently contradictory dispositions or orientations are negotiated by the judicious exercise of mistrust and suspicion. The article suggests not only that mistrust is valued and cultivated as an indispensable practical resource for success in Yiwu's export trade, but that contingent relations of trust between market players emerge at the interstices of a generalized mutual mistrust, via the mobilization of practices of hospitality, commensality, and masculine conviviality. Indeed, feelings of amity and mutuality elicited by the performance of modalities of social intimacy become the affective terrain upon which divergent economic interests might be reconciled and taken forward. That is, mistrust might not lead to generalized distrust, instead a situational or contingent trust might actually emerge through the judicious exercise of mistrust.


Author(s):  
Olga Markova ◽  
Valentina Maslennikova

The largest countries of the world are inevitably involved in various global processes, both natural and socio-economic. These countries have common features and characteristic differences in the state of their territorial resources; the study of these characteristics is of interest for the global prospects of sustainable development. A large territory provides a variety of natural conditions and resources for the country; however, not in all countries it is possible to effectively use them in the economy throughout the all country. An analysis of their territorial resources was carried out for the six largest countries of the world according to the following parameters: area, efficiency, environmental load on the territory of the country, number, density, forecast of population growth or decline for 2050, main agricultural land (arable land, pastures, the provision of the population, degradation and pollution of the soils), forest resources (including security per capita, share in the area of countries), fresh water resources (including per capita provision and availability), greenhouse gas emissions, including per capita, the proportion of mammals endangered, proportion of areas of preserved ecosystems. The data obtained was displayed on the maps; a common legend is built for them in tabular form. A number of other parameters of the state of territorial resources and the environment were also studied. In the process of research, the most important cities of these countries were also studied and diagrams showing their similarities and differences in a number of indicators were constructed: area, population and population density, time of foundation, climatic and landscape parameters, the presence of UNESCO World Heritage Sites, high-rise construction parameters. The developed methodology is effective for assessing a variety of data on territorial resources that can be used to build models of sustainable development of the largest countries and regions of the Earth.


2020 ◽  
Vol 47 (3) ◽  
pp. 159-173
Author(s):  
Paola Migliorini ◽  
Paolo Bàrberi ◽  
Stéphane Bellon ◽  
Tommaso Gaifami ◽  
Vassilis D. Gkisakis ◽  
...  

Seven potential controversial topics in agroecology are presented and discussed from a European perspective comparing the position of Agroecology Europe (AEEU) obtained from an iterative, participatory approach with members and compared with published literature, including views from other parts of the world. The seven controversial topics as follows: i) use of agrochemicals; ii) small-scale and peasant farming versus larger farms; iii) technological innovations in agriculture and precision farming; iv) biotechnology and genetic engineering in agriculture; v) local and short food circuits; vi) social justice; vii) gender perspective. The analysis shows that there are diverse points of view related to geographical area and sociopolitical contexts. However, there are several convergences in the ambition to redesign farming and food systems, as a lever acting on several topics, and in considering agroecology with a holistic, participatory, multiactor approach for the needed transition.


2013 ◽  
Vol 15 (1) ◽  
pp. 189 ◽  
Author(s):  
M. VACCHI ◽  
M. MONTEFALCONE ◽  
V. PARRAVICINI ◽  
A. ROVERE ◽  
P. VASSALLO ◽  
...  

Spatial modelling is an emerging approach to the management of coastal marine habitats, as it helps understanding and predicting the results of global change. This paper reviews critically two recent examples developed in Liguria, an administrative region of NW Italy. The first example, aiming at predicting habitat status depending on pressures, provides managers with the opportunity of envisaging different scenarios for the consequences of coastal development choices. The second example defines the status of an important Mediterranean coastal marine habitat (Posidonia oceanica meadows) under natural conditions, allowing for quantifying human impacts on regressed meadows. Both modelling approaches are useful to define the targets of coastal management, and may help choosing the best management option. Well-planned and sustained monitoring is essential to model validation and improvement.


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