scholarly journals The Be Phenomenon: Connections to B-supergiants

2000 ◽  
Vol 175 ◽  
pp. 37-47
Author(s):  
Andreas Kaufer
Keyword(s):  
Physical Properties ◽  
Large Scale ◽  
Spectral Characteristics ◽  
Evolutionary Status ◽  
Circumstellar Envelopes ◽  
Rotational Modulation ◽  
Open Questions ◽  
Long Term Monitoring ◽  
Term Monitoring

AbstractIn this contribution the spectral characteristics, physical properties, and the evolutionary status of B-type supergiants is reviewed with respect to the Be phenomenon. Long-term monitoring campaigns in the UV and the optical have recently revealed the distinct variability patterns of the photospheric and the emission-line spectra of this class. The various proposed scenarios for the spatially structured circumstellar envelopes and their rotational modulation are presented. The possibility of generating and maintaining large-scale wind structures by photospheric processes which structure the underlying stellar surfaces is discussed. Some open questions in connection with these hypotheses will be identified.

Large-scale, long-term monitoring of Caribbean coral reefs: Simple, quick, inexpensive techniques

1994 ◽  
Vol 421 ◽  
pp. 1-19 ◽  
Author(s):  
Richard B. Aronson ◽  
P. J. Edmunds ◽  
W. F. Precht ◽  
D. W. Swanson ◽  
D. R. Levitan
Keyword(s):  
Coral Reefs ◽  
Large Scale ◽  
Caribbean Coral ◽  
Caribbean Coral Reefs ◽  
Long Term Monitoring ◽  
Term Monitoring

scholarly journals The Italian TREETALKER NETWORK (ITT-Net): continuous large scale monitoring of tree functional traits and vulnerabilities to climate change

2020 ◽  
Author(s):  
Simona Castaldi ◽  
Serena Antonucci ◽  
Shahla Asgharina ◽  
Giovanna Battipaglia ◽  
Luca Belelli Marchesini ◽  
...  
Keyword(s):  
Climate Change ◽  
Real Time ◽  
High Frequency ◽  
Large Scale ◽  
Operation Mode ◽  
Cloud Services ◽  
Long Term Monitoring ◽  
The Impact ◽  
Term Monitoring

<p>The  <strong>Italian TREETALKER NETWORK (ITT-Net) </strong>aims to respond to one of the grand societal challenges: the impact of climate changes on forests ecosystem services and forest dieback. The comprehension of the link between these phenomena requires to complement the most classical approaches with a new monitoring paradigm based on large scale, single tree, high frequency and long-term monitoring tree physiology, which, at present, is limited by the still elevated costs of multi-sensor devices, their energy demand and maintenance not always suitable for monitoring in remote areas. The ITT-Net network will be a unique and unprecedented worldwide example of real time, large scale, high frequency and long-term monitoring of tree physiological parameters. By spring 2020, as part of a national funded project (PRIN) the network will have set 37 sites from the north-east Alps to Sicily where a new low cost, multisensor technology “the TreeTalker®” equipped to measure tree radial growth, sap flow, transmitted light spectral components related to foliage dieback and physiology and plant stability (developed by Nature 4.0), will monitor over 600 individual trees. A radio LoRa protocol for data transmission and access to cloud services will allow to transmit in real time high frequency data on the WEB cloud with a unique IoT identifier to a common database where big data analysis will be performed to explore the causal dependency of climate events and environmental disturbances with tree functionality and resilience.</p><p>With this new network, we aim to create a new knowledge, introducing a massive data observation and analysis, about the frequency, intensity and dynamical patterns of climate anomalies perturbation on plant physiological response dynamics in order to: 1) characterize the space of “normal or safe tree operation mode” during average climatic conditions; 2) identify the non-linear tree responses beyond the safe operation mode, induced by extreme events, and the tipping points; 3) test the possibility to use a high frequency continuous monitoring system to identify early warning signals of tree stress which might allow to follow tree dynamics under climate change in real time at a resolution and accuracy that cannot always be provided through forest inventories or remote sensing technologies.</p><p>To have an overview of the ITT Network you can visit www.globaltreetalker.org</p><p> </p>

scholarly journals Evaluation of the Continuous Monitoring of Land Disturbance Algorithm for Large-Scale Mangrove Classification

2021 ◽  
Vol 13 (19) ◽  
pp. 3978
Author(s):  
Katie Awty-Carroll ◽  
Pete Bunting ◽  
Andy Hardy ◽  
Gemma Bell
Keyword(s):  
Continuous Monitoring ◽  
Large Scale ◽  
Data Availability ◽  
Mangrove Forests ◽  
Mangrove Species ◽  
Land Disturbance ◽  
Long Term Monitoring ◽  
The Impact ◽  
Term Monitoring

Mangrove forests are of high biological, economic, and ecological importance globally. Growing within the intertidal zone, they are particularly vulnerable to the effects of climate change in addition to being threatened on local scales by over-exploitation and aquaculture expansion. Long-term monitoring of global mangrove populations is therefore highly important to understanding the impact of these threats. However, data availability from satellites is often limited due to cloud cover. This problem can be mitigated using a season-trend modelling approach such as Continuous Monitoring of Land Disturbance (COLD). COLD operates by using every available observation on a pixel-wise basis, removing the need for whole cloud free images. The approach can be used to better classify land cover by taking into account the underlying seasonal variability, and can also be used to extrapolate between data points to obtain more accurate long term trends. To demonstrate the utility of COLD for global mangrove monitoring, we applied it to five study sites chosen to represent a range of mangrove species, forest types, and quantities of available data. The COLD classifier was trained on the Global Mangrove Watch 2010 dataset and applied to 30 years of Landsat data for each site. By increasing the period between model updates, COLD was successfully applied to all five sites (2253 scenes) in less than four days. The method achieved an overall accuracy of 92% with a User’s accuracy of 77% and a Dice score of 0.84 for the mangrove class. The lowest User’s accuracy was for North Kalimantan (49.9%) due to confusion with mangrove palms. However, the method performed extremely well for the Niger Delta from the 2000s onwards (93.6%) despite the absence of any Landsat 5 data. Observation of trends in mangrove extent over time suggests that the method was able to accurately capture changes in extent caused by the 2014/15 mangrove die-back event in the Gulf of Carpentaria and highlighted a net loss of mangroves in the Matang Forest Reserve over the last two decades, despite ongoing management. COLD is therefore a promising methodology for global, long-term monitoring of mangrove extent and trends.

Plastic plants: Long-term monitoring of macroplastic entrapment by water hyacinths in the Saigon river 

2021 ◽  
Author(s):  
Louise Schreyers ◽  
Tim van Emmerik ◽  
Thanh-Khiet L. Bui ◽  
Lauren Biermann ◽  
Dung Le Quang ◽  
...  
Keyword(s):  
Large Scale ◽  
River System ◽  
Spatiotemporal Variability ◽  
Monitoring Techniques ◽  
Monitoring Effort ◽  
Long Term Monitoring ◽  
Water Plants ◽  
Water Hyacinths ◽  
Term Monitoring

<p>Our recent field-based study undertaken at the Saigon river, Vietnam, shows that water hyacinths are responsible for entraining and transporting a majority of floating macroplastic litter. These invasive, free-floating water plants can form patches of several meters in length and width and tend to aggregate large amounts of plastic litter. Over the course of a six-week study, we demonstrated that 78% of the floating macroplastic observed were carried downstream accumulated within these floating plant patches.</p><p>The strong seasonality of water hyacinths, coupled with the temporal variability in macroplastic flux, calls for a longer monitoring effort. To this end, a one-year monitoring campaign is currently being undertaken at the Saigon river, which will apply satellite imagery, drone, camera imagery analysis and visual counting from bridges. Combined, these methods can help to characterize the contribution of hyacinths to macroplastic transport and accumulation at different temporal (from hours/days to weeks/months) and spatial (from sample sites to the river system) scales.</p><p>We evaluate the selected monitoring techniques, and present the preliminary results of this large-scale monitoring effort. We provide the first scientific overview of the contribution of water hyacinths in plastic transport relative to the total plastic transport, and its spatiotemporal variability. In addition, we assess the monitoring techniques used and provide suggestions for similar long-term monitoring strategies.</p>

Perspectives on biotic responses to repeated wildfires from decades of long-term empirical studies

2022 ◽  
Vol preprint (2022) ◽  
Author(s):  
David Lindenmayer ◽  
Elle Bowd ◽  
Chris MacGregor ◽  
Lachlan McBurney
Keyword(s):  
Large Scale ◽  
Fire History ◽  
Fire Severity ◽  
Salvage Logging ◽  
Eastern Australia ◽  
Ecosystem Condition ◽  
Long Term Monitoring ◽  
Term Monitoring ◽  
Long Term Studies

ABSTRACT Fire can have marked impacts on biodiversity and on ecosystem condition. However, it is the sequence of multiple fires over a prolonged period of time which can have the most marked effects on biodiversity and on ecosystem condition. A good understanding of these effects comes from long-term studies. In this article we outline some of the key perspectives on the effects of fire on ecosystems and biodiversity from two large-scale, long-term monitoring studies in south-eastern Australia. These are studies in the montane ash forests of the Central Highlands of Victoria and at Booderee National Park in the Jervis Bay Territory. These studies have shown that the effects of fires are strongly influenced by: (1) The condition of an ecosystem before a fire (e.g. the age of a forest at the time it is burnt). (2) Conditions after the fire such as the extent of herbivory in regenerating vegetation and whether the ecosystem is subject to post-fire (salvage) logging. (3) Fire history (e.g. the number of past fires and the time since the previous fire). And, (4) Interactions between fire and other ecosystem drivers such as logging. We discuss some of the key implications for conservation and resource management that arise from these studies including the need to: (a) Reduce the number of stressors in some ecosystems to facilitate post-fire recovery. (b) Recognize that pre-fire human disturbances can elevate fire severity in some forest ecosystems, with corresponding negative effects on elements of the biota, and, (c) Acknowledge the inherent patchiness of wildfires and the value of unburnt areas and places burnt at low severity as critical refugia for some species; it is critical that these locations are managed accordingly (e.g. by limited additional disturbances within them). Finally, many of the insights discussed in this article have emerged only through long-term studies. More long-term monitoring and research is needed to truly understand and better manage fire in Australian ecosystems.

Climate change alone cannot explain altered tick distribution across Europe: a spotlight on endemic and invasive tick species.

2021 ◽  
pp. 125-131
Author(s):  
Frederic Stachurski ◽  
Nathalie Boulanger ◽  
Adrien Blisnick ◽  
Laurence Vial ◽  
Sarah Bonnet
Keyword(s):  
Climate Change ◽  
Tick Species ◽  
Large Scale ◽  
External Environment ◽  
Climatic Conditions ◽  
Climatic Impact ◽  
Long Term Monitoring ◽  
The Impact ◽  
Term Monitoring

Abstract The effect of climate on the evolution of tick populations remains difficult to disentangle from other possible causes and undoubtedly varies depending on the region concerned and local tick species. Large-scale, long-term monitoring is, therefore, necessary to accurately assess climatic impact on tick populations. Climate change can alter tick populations, either indirectly by affecting vertebrate host populations or directly by increasing or decreasing their numbers. These ectoparasites, and in particular hard ticks, spend almost their entire life cycle in the external environment, thus climatic conditions influence their activity, viability and distribution. This expert opinion aims to illustrate the impact of climate change, and its association with other variables, on the distribution and abundance of tick populations in Europe using Ixodes ricinus and Hyalomma marginatum as typical examples of endemic and invasive species, respectively.

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