Modelling human carrying capacity as a function of food availability

2021 ◽  
Vol 62 ◽  
pp. 318-333
Author(s):  
Diny Zulkarnaen ◽  
Marianito R. Rodrigo
Keyword(s):  
Food Availability ◽  
Carrying Capacity ◽  
Food Production ◽  
Human Population ◽  
Model Parameters ◽  
Estimation Technique ◽  
Dynamical Models ◽  
Explicit Formulas ◽  
Production Index ◽  
Human Carrying Capacity

We assume that human carrying capacity is determined by food availability. We propose three classes of human population dynamical models of logistic type, where the carrying capacity is a function of the food production index. We also employ an integration-based parameter estimation technique to derive explicit formulas for the model parameters. Using actual population and food production index data, numerical simulations of our models suggest that an increase in food availability implies an increase in carrying capacity, but the carrying capacity is “self-limiting” and does not increase indefinitely. doi:10.1017/S1446181120000206

MODELLING HUMAN CARRYING CAPACITY AS A FUNCTION OF FOOD AVAILABILITY

2020 ◽  
pp. 1-16
Author(s):  
DINY ZULKARNAEN ◽  
MARIANITO R. RODRIGO
Keyword(s):  
Food Availability ◽  
Carrying Capacity ◽  
Food Production ◽  
Human Population ◽  
Model Parameters ◽  
Estimation Technique ◽  
Dynamical Models ◽  
Explicit Formulas ◽  
Production Index ◽  
Human Carrying Capacity

Abstract We assume that human carrying capacity is determined by food availability. We propose three classes of human population dynamical models of logistic type, where the carrying capacity is a function of the food production index. We also employ an integration-based parameter estimation technique to derive explicit formulas for the model parameters. Using actual population and food production index data, numerical simulations of our models suggest that an increase in food availability implies an increase in carrying capacity, but the carrying capacity is “self-limiting” and does not increase indefinitely.

scholarly journals How Many People can the Earth Support?

1998 ◽  
Vol 4 (2) ◽  
pp. 170
Author(s):  
Sondi Bootle
Keyword(s):  
Population Growth ◽  
Carrying Capacity ◽  
Human Population ◽  
Modern Technology ◽  
Human Population Growth ◽  
The Past ◽  
The Earth ◽  
The Future ◽  
Heated Debate ◽  
Human Carrying Capacity

A much-heated debate has evolved over the past few decades regarding the future of human population growth and the number of humans that the planet Earth is able to sustain. Some claim that Earth has already reached its human carrying capacity, where others argue that the carrying capacity of the planet is limitless given modern technology. What is clear is that the carrying capacity of the Earth and the future of human population growth is a subject of much uncertainty.

scholarly journals A Theoretical Model for the Transmission Dynamics of the Buruli Ulcer with Saturated Treatment

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Ebenezer Bonyah ◽  
Isaac Dontwi ◽  
Farai Nyabadza
Keyword(s):  
Human Population ◽  
Reproduction Number ◽  
Buruli Ulcer ◽  
Coupled System ◽  
Model Parameters ◽  
The Public ◽  
Treatment Function ◽  
Medical Facilities ◽  
The Stability ◽  
Saturated Treatment

The management of the Buruli ulcer (BU) in Africa is often accompanied by limited resources, delays in treatment, and macilent capacity in medical facilities. These challenges limit the number of infected individuals that access medical facilities. While most of the mathematical models with treatment assume a treatment function proportional to the number of infected individuals, in settings with such limitations, this assumption may not be valid. To capture these challenges, a mathematical model of the Buruli ulcer with a saturated treatment function is developed and studied. The model is a coupled system of two submodels for the human population and the environment. We examine the stability of the submodels and carry out numerical simulations. The model analysis is carried out in terms of the reproduction number of the submodel of environmental dynamics. The dynamics of the human population submodel, are found to occur at the steady states of the submodel of environmental dynamics. Sensitivity analysis is carried out on the model parameters and it is observed that the BU epidemic is driven by the dynamics of the environment. The model suggests that more effort should be focused on environmental management. The paper is concluded by discussing the public implications of the results.

scholarly journals Estimation and optimal control of the multi-scale dynamics of the Covid-19

2021 ◽  
Author(s):  
David Jaurès Fotsa-Mbogne ◽  
Stéphane Yanick Tchoumi ◽  
Yannick Kouakep-Tchaptchie ◽  
Vivient Corneille Kamla ◽  
Jean-Claude Kamgang ◽  
...  
Keyword(s):  
Optimal Control ◽  
Human Population ◽  
Virus Transmission ◽  
Scale Model ◽  
Model Parameters ◽  
Optimal Control Strategy ◽  
Or Efficiency ◽  
Human Virus ◽  
Multi Scale ◽  
Human Density

AbstractThis work aims at a better understanding and the optimal control of the spread of the new severe acute respiratory corona virus 2 (SARS-CoV-2). We first propose a multi-scale model giving insights on the virus population dynamics, the transmission process and the infection mechanism. We consider 10 compartments in the human population in order to take into accounts the effects of different specific mitigation policies: susceptible, infected, infectious, quarantined, hospitalized, treated, recovered, non-infectious dead, infectious dead, buried. The population of viruses is also partitioned into 10 compartments corresponding respectively to each of the first nine human population compartments and the free viruses available in the environment. Indeed, we have human to human virus transmission, human to environment virus transmission, environment to human virus transmission and self infection by susceptible individuals. We show the global stability of the disease free equilibrium if a given threshold 𝒯0 is less or equal to 1 and we provide how to compute the basic reproduction number ℛ0. A convergence index 𝒯1 is also defined in order to estimate the speed at which the disease extincts and an upper bound to the time of extinction is given. The existence of the endemic equilibrium is conditional and its description is provided. We evaluate the sensitivity of ℛ0, 𝒯0 and 𝒯1 to control parameters such as the maximal human density allowed per unit of surface, the rate of disinfection both for people and environment, the mobility probability, the wearing mask probability or efficiency, and the human to human contact rate which results from the previous one. Except the maximal human density allowed per unit of surface, all those parameters have significant effects on the qualitative dynamics of the disease. The most significant is the probability of wearing mask followed by the probability of mobility and the disinfection rate. According to a functional cost taking into consideration economic impacts of SARS-CoV-2, we determine and discuss optimal fighting strategies. The study is applied to real available data from Cameroon and an estimation of model parameters is done. After several simulations, social distancing and the disinfection frequency appear as the main elements of the optimal control strategy.

scholarly journals Management of Gogo Rice Production in Realizing the Commercialization of Marginal Land Farming Households in Yogyakarta

2021 ◽  
Vol 16 (2) ◽  
pp. 373-378
Author(s):  
Wulandari Dwi Etika Rini ◽  
Endang Siti Rahayu ◽  
Mohamad Harisudin ◽  
Supriyadi Supriyadi
Keyword(s):  
Carrying Capacity ◽  
Food Production ◽  
Sampling Method ◽  
Agricultural Land ◽  
Upland Rice ◽  
Household Consumption ◽  
Rice Production ◽  
Marginal Land ◽  
Marketable Surplus ◽  
Farming Households

The land is an important factor for people whose lives depend on the agricultural sector. The need for land for various uses has resulted in decreasing agricultural land which could have implications for decreasing food production. Alternative options which are expected to increase the potential for food production are the utilization of marginal land. Farmers with marginal land need to manage their production to meet household needs. So it is important to examine the marketable surplus, the level of commercialization, and the carrying capacity of marginal land. The research area was taken by purposive sampling method in Gunungkidul Yogyakarta. The samples taken were upland rice farmer households with the simple random sampling method. The marketable surplus analysis uses a marketable surplus formula, then the percentage is used to determine the level of farm commercialization. The carrying capacity analysis is carried out using the carrying capacity formula. The results showed that farmer households manage rice production by allocating an average of 59.1% for marketed and 40.9% for household consumption. The allocation of marketable surplus is greater than for household consumption, this shows that gogo rice farming households are towards commercially. The marginal land carrying capacity of 0.641 indicates that the land cannot be developed in an expansive and exploratory manner. The implication is in increasing upland rice production on marginal land, namely by an intensification of farming.

scholarly journals Comparative terrestrial feed and land use of an aquaculture-dominant world

2018 ◽  
Vol 115 (20) ◽  
pp. 5295-5300 ◽  
Author(s):  
Halley E. Froehlich ◽  
Claire A. Runge ◽  
Rebecca R. Gentry ◽  
Steven D. Gaines ◽  
Benjamin S. Halpern
Keyword(s):  
Land Use ◽  
Food Production ◽  
Human Population ◽  
Protein Production ◽  
Anthropogenic Impacts ◽  
Meat Production ◽  
Feed Composition ◽  
Land Sparing ◽  
Country Level ◽  
Future Potential

Reducing food production pressures on the environment while feeding an ever-growing human population is one of the grand challenges facing humanity. The magnitude of environmental impacts from food production, largely around land use, has motivated evaluation of the environmental and health benefits of shifting diets, typically away from meat toward other sources, including seafood. However, total global catch of wild seafood has remained relatively unchanged for the last two decades, suggesting increased demand for seafood will mostly have to rely on aquaculture (i.e., aquatic farming). Increasingly, cultivated aquatic species depend on feed inputs from agricultural sources, raising concerns around further straining crops and land use for feed. However, the relative impact and potential of aquaculture remains unclear. Here we simulate how different forms of aquaculture contribute and compare with feed and land use of terrestrial meat production and how spatial patterns might change by midcentury if diets move toward more cultured seafood and less meat. Using country-level aquatic and terrestrial data, we show that aquaculture requires less feed crops and land, even if over one-third of protein production comes from aquaculture by 2050. However, feed and land-sparing benefits are spatially heterogeneous, driven by differing patterns of production, trade, and feed composition. Ultimately, our study highlights the future potential and uncertainties of considering aquaculture in the portfolio of sustainability solutions around one of the largest anthropogenic impacts on the planet.

Subsampling Reduces Sorting Effort for Waterfowl Foods in Salt-Marsh Core Samples

2014 ◽  
Vol 5 (2) ◽  
pp. 380-386 ◽  
Author(s):  
Mark C. Livolsi ◽  
Kevin M. Ringelman ◽  
Christopher K. Williams
Keyword(s):  
Salt Marsh ◽  
Food Availability ◽  
Carrying Capacity ◽  
Processing Time ◽  
Soil Core ◽  
Habitat Types ◽  
Core Samples ◽  
Large Numbers ◽  
Significant Difference ◽  
Time Savings

Abstract Waterfowl researchers often use soil core samples to estimate food availability in foraging habitats, and these estimates are needed for bioenergetic models of carrying capacity. However, core sampling is frequently a time- and resource-intensive process, and some researchers have suggested that subsampling may be a valuable way to reduce processing time. We evaluated whether 10% and 25% by mass subsampling are appropriate techniques for reducing core-sorting effort while maintaining precision for samples taken in six separate habitat types along the Delaware bayshore. We found no significant difference between biomass found in 100% sorted cores and estimated biomass obtained by 10% and 25% subsampling. We found that 10% subsampling offered the greatest time savings, reducing mean sorting times by 77% (from 13.7 hours to 3.3 hours) from 100% sorted cores. We recommend that researchers consider subsampling to reduce core-sorting effort and cost, particularly when processing large numbers of cores.

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