scholarly journals Integrating Economic dynamics into Ecological Networks: The case of fishery sustainability

2019 ◽  
Author(s):  
Paul Glaum ◽  
Valentin Cocco ◽  
Fernanda S. Valdovinos
Keyword(s):  
Network Theory ◽  
Management Strategies ◽  
Single Species ◽  
Fishing Effort ◽  
Ecological Networks ◽  
Ecological Network ◽  
Ecological Dynamics ◽  
Natural Systems ◽  
Insight Into

Summary/AbstractUnderstanding and sustainably managing anthropogenic impact on ecosystems requires studying the integrated economic -ecological dynamics driving coupled human-natural systems. Here, we expand ecological network theory to study fishery sustainability by incorporating economic drivers into food-web models to evaluate the dynamics of thousands of single-species fisheries across hundreds of generated food-webs and two management strategies. Analysis reveals harvesting high population biomass species can initially support fishery persistence, but threatens long term economic and ecological sustainability by indirectly inducing extinction cascades in non-harvested species. This dynamic is exacerbated in open access fisheries where profit driven growth in fishing effort increases perturbation strength. Results demonstrate the unique insight into both ecological dynamics and sustainability garnered from considering economically dynamic fishing effort in the network.One Sentence SummaryIntegrating economic drivers into ecological networks reveal non-linear drivers of sustainability in fisheries.

scholarly journals Integrating economic dynamics into ecological networks: The case of fishery sustainability

2020 ◽  
Vol 6 (45) ◽  
pp. eaaz4891
Author(s):  
Paul Glaum ◽  
Valentin Cocco ◽  
Fernanda S. Valdovinos
Keyword(s):  
Open Access ◽  
Large Scale ◽  
Anthropogenic Impacts ◽  
Management Strategies ◽  
Network Models ◽  
Single Species ◽  
Fishing Effort ◽  
Economic Dynamics ◽  
Trophic Network

Understanding anthropogenic impacts on ecosystems requires investigating feedback processes between ecological and economic dynamics. While network ecology has advanced our understanding of large-scale communities, it has not robustly coupled economic drivers of anthropogenic impact to ecological outcomes. Leveraging allometric trophic network models, we study such integrated economic-ecological dynamics in the case of fishery sustainability. We incorporate economic drivers of fishing effort into food-web network models, evaluating the dynamics of thousands of single-species fisheries across hundreds of simulated food webs under fixed-effort and open-access management strategies. Analyzing simulation results reveals that harvesting species with high population biomass can initially support fishery persistence but threatens long-term economic and ecological sustainability by indirectly inducing extinction cascades in non-harvested species. This dynamic is exacerbated in open-access fisheries where profit-driven growth in fishing effort increases perturbation strength. Our results demonstrate how network theory provides necessary ecological context when considering the sustainability of economically dynamic fishing effort.

Managing growth overfishing with multiannual compromise strategies

1997 ◽  
Vol 54 (10) ◽  
pp. 2255-2276 ◽  
Author(s):  
P Marchal
Keyword(s):  
Management Strategies ◽  
Fishing Effort ◽  
Reference Points ◽  
Long Term Outcomes ◽  
Northeast Atlantic ◽  
Factors Influencing ◽  
Optimal Balance ◽  
Short And Long Term ◽  
Mobile Target

Most of the Northeast Atlantic stocks are currently fished above the biological reference points (e.g., Fmax). In attempting to achieve such targets, advisers and managers have faced two main problems. First, it is impractical to (i) simultaneously maximize yields, stabilize fisheries, and safeguard stocks and (ii) optimize both short- and long-term outcomes for the industry. Second is the lack of predictability, several years ahead, in factors influencing decisions. This study addresses these twin issues by exploring the relative performances of various multiannual and compromise (or composite) management strategies. Multiannual fishing efforts are set in advance for a ``resolution'' period of several years, at the end of which they are updated. They are calculated to satisfy a prior weighted compromise amongst three criteria: (i) minimizing fishing effort variability, (ii) minimizing catch variability, and (iii) reaching a ``mobile target:'' the latter is defined with a second weighted compromise between the long-term target and the fishing effort at the beginning of the resolution period. A safe and optimal balance between all the short- and long-term fishery outcomes is found with a 5-year resolution period, during which the mobile target is split into 40-60% of the long-term target, and 60-40% of the fishing effort at the start of the resolution period, while criteria i, ii, and iii are weighted equally.

scholarly journals Urinary Tract Infection in Children: An Update

2012 ◽  
Vol 36 (2) ◽  
pp. 90-97 ◽  
Author(s):  
Kamrul Laila ◽  
Eliza Roy ◽  
Md Habibur Rahman ◽  
Ranjit Ranjan Roy
Keyword(s):  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Management Strategies ◽  
Single Species ◽  
Common Disease ◽  
Urinary Tract Abnormality ◽  
Number Of Children

Background: A large number of children with Urinary Tract Infection (UTI) are seen in the community by general practitioners , but there is frequently delay in treatment and not all are referred for further investigations. There is evidence that many cases are misdiagnosed. It is important to optimize diagnostic and management strategies. Result: UTI is an important cause of acute illness, it may be a marker of underlying urinary tract abnormality. Bacteria causes the large majority of UTI in children- Escherichia coli is the most common (90%) bacterial cause. Urine culture & sensitivity is the gold standard for the diagnosis and mandatory for confirmation of UTI. On culture, a colony count of more than 105/ml organisms of a single species is considered confirmatory of UTI. But there is a strong recommendation that , presence of both pyuria and at least 50,000 Colony Forming Unit (CFU) / ml of a single uropathogen in an appropriately collected specimen makes the diagnosis . There is a recommended imaging schedule in childhood UTI to detect anatomical abnormality. Management depends on type of infection. There is no role of prophylactic antibiotics to prevent febrile recurrent UTI without VUR. Conclusion: UTI is a very common disease and may be associated with renal abnormalities and long term squeale. There is debate about best investigation and management strategies. The greatest potential for prevention of renal damage lies in increased awareness, better diagnosis and management of young children with UTI in primary healthcare. DOI: http://dx.doi.org/10.3329/bjch.v36i2.13085 Bangladesh J Child Health 2012; Vol 36 (2): 90-97

scholarly journals Monitoring artisanal hilsa fishery for economic efficient fisheries policy

2015 ◽  
Vol 43 (1) ◽  
pp. 37-53 ◽  
Author(s):  
Masud Ara Mome ◽  
Ragnar Arnason
Keyword(s):  
Economic Benefit ◽  
Single Species ◽  
Fishing Effort ◽  
Economic Benefits ◽  
Present Value ◽  
Effort Level ◽  
Fisheries Policy ◽  
Tenualosa Ilisha ◽  
Dynamic Path

The hilsa shad (Tenualosa ilisha) fishery contributes to the largest single species fishery in Bangladesh. In this paper, a simple bio-economic year-class based model was developed from 1987 & 2007 fishing data to describe the fishery and examine its properties. With the help of this model, the optimum sustainable yield of the fishery was calculated and compared to the existing situation. The model was further used to locate socially and economically reasonable dynamic paths from the current situation to the optimal state. The results indicate that the fishing effort (measured in standardized boat units) required maintaining a maximum sustainable economic benefit is about one-third of the current fishing effort. At this sustainable fishing effort level, annual net economic benefits from the fishery amounted for closed to US$ 260 million compared to virtually nothing at present. The present value of the fishery along a moderate effort adjustment path to this long term equilibrium position was US$ 3,650 million at 6% rate of discount. The dynamic path that maximized the present value of the fishery involved quite dramatic effort reductions for the first two years. Such a path would probably increase the present value of the fishery by perhaps 8-10%.Bangladesh J. Zool. 43(1): 37-53, 2015

The Ethics of Ecosystem Management

2016 ◽  
Author(s):  
Marion Hourdequin
Keyword(s):  
Ecosystem Services ◽  
Ecosystem Management ◽  
Adaptive Learning ◽  
Management Strategies ◽  
Single Species ◽  
Ecological Systems ◽  
Ethical Challenges ◽  
Natural Systems ◽  
Core Concepts ◽  
Original Goal

Ecosystem management is an integrative, systems-based approach developed in response to the inadequacy of land management strategies centered on single species or resources such as timber. Contemporary ecosystem management acknowledges the dynamism of natural systems, need for ongoing adaptive learning, and importance of citizen engagement, especially in managing public lands. However, ecosystem management faces both conceptual and ethical challenges. Core concepts—such as ecosystem, stability, health, and resilience—remain difficult to define and operationalize. In addition, rapid directional changes in ecological systems have destabilized the use of historical baselines for management. One response to this challenge is to seek new moorings in an “ecosystem services” approach, focused on the role of ecological systems in supporting human interests and needs. Although ecosystem management began as a way to broaden beyond a focus on maximizing yields of particular resources, ecosystem services approaches may—ironically—reintroduce reductionistic tendencies that thwart this original goal.

A comparison of conventional and alternative agroecosystems using alfalfa (Medicago sativa) and winter wheat (Triticum aestivum)

2005 ◽  
Vol 20 (1) ◽  
pp. 38-47 ◽  
Author(s):  
Laura E. Skelton ◽  
Gary W. Barrett
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Medicago Sativa ◽  
Insect Pests ◽  
Agricultural Practices ◽  
Plant Nitrogen ◽  
Natural Systems ◽  
No Till ◽  
Insight Into

AbstractNatural systems agriculture is based on an understanding that natural systems are self-sustaining due to regulatory mechanisms and processes that help to ensure the long-term maintenance of the ecosystem. An agroecosystem modeled after nature should encompass greater stability and biodiversity at all levels of organization than an agroecosystem based on conventional agricultural practices. The main objective of this study was to determine whether agroecosystems modeled after nature exhibit advantages over conventional agroecosystems. Five treatments were examined: winter wheat (Triticum aestivum L.) monoculture, alfalfa (Medicago sativa L.) monoculture, strip-cropped alfalfa and wheat, and two alfalfa–wheat intercrops (one no-till and one conservation-till). Indicators of ecosystem function studied included primary productivity, soil fertility, plant nitrogen (N) concentration, and abundances of arthropod pests and predators. No fertilizers or pesticides were used prior to or during this investigation. Monoculture, strip-crop and conservation-till treatments produced significantly higher yields than no-till intercropped alfalfa and wheat. Although yields from the no-till intercrop were low, wheat protein values were comparable to other treatments. Soil N concentrations tended to be high in treatments containing alfalfa. Insect pests preferred alfalfa and were, therefore, often more abundant in treatments containing high percentages of alfalfa, as were predators such as spiders. Researching alternatives to monoculture agroecosystems, such as the intercrop systems in this study, may provide us insight into a true natural systems agriculture.

Turkish Muslims in a German city: Entrepreneurial and residential self-determination

2015 ◽  
Vol 12 (1) ◽  
pp. 1-12
Author(s):  
Sarah Hackett
Keyword(s):  
Residential Patterns ◽  
Academic Literature ◽  
Self Employment ◽  
German City ◽  
Post War ◽  
Oral History Interviews ◽  
The City ◽  
Insight Into ◽  
Term Objective

Drawing upon a collection of oral history interviews, this paper offers an insight into entrepreneurial and residential patterns and behaviour amongst Turkish Muslims in the German city of Bremen. The academic literature has traditionally argued that Turkish migrants in Germany have been pushed into self-employment, low-quality housing and segregated neighbourhoods as a result of discrimination, and poor employment and housing opportunities. Yet the interviews reveal the extent to which Bremen’s Turkish Muslims’ performances and experiences have overwhelmingly been the consequences of personal choices and ambitions. For many of the city’s Turkish Muslim entrepreneurs, self-employment had been a long-term objective, and they have succeeded in establishing and running their businesses in the manner they choose with regards to location and clientele, for example. Similarly, interviewees stressed the way in which they were able to shape their housing experiences by opting which districts of the city to live in and by purchasing property. On the whole, they perceive their entrepreneurial and residential practices as both consequences and mediums of success, integration and a loyalty to the city of Bremen. The findings are contextualised within the wider debate regarding the long-term legacy of Germany’s post-war guest-worker system and its position as a “country of immigration”.

Connecting Crop Nutrient Use Efficiency to Future Soil Productivity

2018 ◽  
Vol 102 (4) ◽  
pp. 8-10
Author(s):  
Fernando García ◽  
Andrés Grasso ◽  
María González Sanjuan ◽  
Adrián Correndo ◽  
Fernando Salvagiotti
Keyword(s):  
Nutrient Management ◽  
Nutrient Use Efficiency ◽  
Management Strategies ◽  
Crop Productivity ◽  
Soil Productivity ◽  
Nutrient Use ◽  
Grain Crop ◽  
Wide Scale ◽  
Use Efficiency

Trends over the past 25 years indicate that Argentina’s growth in its grain crop productivity has largely been supported by the depletion of the extensive fertility of its Pampean soils. Long-term research provides insight into sustainable nutrient management strategies ready for wide-scale adoption.

Petroclival meningiomas: long-term outcomes of multimodal treatments and management strategies based on 30 years of experience at a single institution

2020 ◽  
Vol 132 (6) ◽  
pp. 1675-1682 ◽  
Author(s):  
Jin Wook Kim ◽  
Hee-Won Jung ◽  
Yong Hwy Kim ◽  
Chul-Kee Park ◽  
Hyun-Tai Chung ◽  
...  
Keyword(s):  
Adjuvant Treatment ◽  
Management Strategies ◽  
Local Tumor Control ◽  
Tumor Control ◽  
Years Of Experience ◽  
Local Tumor ◽  
Long Term Outcomes ◽  
Single Institution ◽  
Petroclival Meningiomas

OBJECTIVEA thorough investigation of the long-term outcomes and chronological changes of multimodal treatments for petroclival meningiomas is required to establish optimal management strategies. The authors retrospectively reviewed the long-term clinical outcomes of patients with petroclival meningioma according to various treatments, including various surgical approaches, and they suggest treatment strategies based on 30 years of experience at a single institution.METHODSNinety-two patients with petroclival meningiomas were treated surgically at the authors’ institution from 1986 to 2015. Patient demographics, overall survival, local tumor control rates, and functional outcomes according to multimodal treatments, as well as chronological change in management strategies, were evaluated. The mean clinical and radiological follow-up periods were 121 months (range 1–368 months) and 105 months (range 1–348 months), respectively.RESULTSA posterior transpetrosal approach was most frequently selected and was followed in 44 patients (48%); a simple retrosigmoid approach, undertaken in 30 patients, was the second most common. The initial extent of resection and following adjuvant treatment modality were classified into 3 subgroups: gross-total resection (GTR) only in 13 patients; non-GTR treatment followed by adjuvant radiosurgery or radiation therapy (non-GTR+RS/RT) in 56 patients; and non-GTR without adjuvant treatment (non-GTR only) in 23 patients. The overall progression-free survival rate was 85.8% at 5 years and 81.2% at 10 years. Progression or recurrence rates according to each subgroup were 7.7%, 12.5%, and 30.4%, respectively.CONCLUSIONSThe authors’ preferred multimodal treatment strategy, that of planned incomplete resection and subsequent adjuvant radiosurgery, is a feasible option for the management of patients with large petroclival meningiomas, considering both local tumor control and postoperative quality of life.

Investigation of a New Approach to Predict Water Quality Extremes with a Case Study of Chemical Determinands in Stream Water

1991 ◽  
Vol 24 (6) ◽  
pp. 25-33
Author(s):  
A. J. Jakeman ◽  
P. G. Whitehead ◽  
A. Robson ◽  
J. A. Taylor ◽  
J. Bai
Keyword(s):  
Water Quality ◽  
Stream Water ◽  
Probability Distributions ◽  
Management Strategies ◽  
Hybrid Modelling ◽  
Trend Model ◽  
Environmental Extremes ◽  
Modelling Approach

The paper illustrates analysis of the assumptions of the statistical component of a hybrid modelling approach for predicting environmental extremes. This shows how to assess the applicability of the approach to water quality problems. The analysis involves data on stream acidity from the Birkenes catchment in Norway. The modelling approach is hybrid in that it uses: (1) a deterministic or process-based description to simulate (non-stationary) long term trend values of environmental variables, and (2) probability distributions which are superimposed on the trend values to characterise the frequency of shorter term concentrations. This permits assessment of management strategies and of sensitivity to climate variables by adjusting the values of major forcing variables in the trend model. Knowledge of the variability about the trend is provided by: (a) identification of an appropriate parametric form of the probability density function (pdf) of the environmental attribute (e.g. stream acidity variables) whose extremes are of interest, and (b) estimation of pdf parameters using the output of the trend model.

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