Population viability analysis

Understanding the risks of extinction faced by different populations can help to identify conservation priorities, while the formal consideration of how different interventions affect the probability of persistence can guide the choice of conservation actions. PVA has been a cornerstone of quantitative, species-focused conservation since the s. Although it is sometimes characterized rather narrowly as simply the modelling of population trajectories, PVA is actually a much richer endeavor.

Population viability analysis

Trends to Abstract Throughout history, the expansion of human population has been Population viability analysis by a steady growth in our use of high-quality exosomatic energy.

The operation of our present industrial civilization is wholly dependent on access to a very large amount of energy of various types.

If the availability of this energy were to decline significantly it could have serious repercussions for civilization and the human population it supports. This paper constructs production models for the various energy sources we use and projects their likely supply evolution out to the year The full energy picture that emerges is then translated into a population model based on an estimate of changing average per-capita energy consumption over the century.

Population viability analysis

Finally, the impact of ecological damage is added to the model to arrive at a final population estimate. This model, known as the "World Energy and Population" model, or WEAP, suggests that the world's population will decline significantly over the course of the century.

Introduction During the historically recent period of global industrialization, the level of human population has been closely related to the amount of Population viability analysis we have used.

Over the last forty years, the per capita energy consumption has averaged about 1. As industrialization has progressed, the amount of per capita energy used has also increased, rising from a global average of 1. As the global energy supply tripled over that time, the population has doubled.

Figure 1 shows the close relationship between global energy consumptionworld GDP and global population and implies that an overall increase in the energy supply has supported the increase in population.

Population viability analysis

Can we assume that there would be negative consequences for the human population if our energy supplies should start to diminish? In this paper I shall present my estimate of the world energy situation over the next century, and tie that to a projection of the human population from now to World Energy, GDP and Population, to Methodology The analysis in this paper is supported by a model of trends in energy production.

The model is based on historical data of actual energy production, connected to projections that are drawn from the thinking of various expert energy analysts as well as my own interpretation of future directions. Historical production in each category except for renewable energy has been taken from the BP Statistical Review of World Energy In order to permit comparison between categories I use a standard measure called the tonne of oil equivalent toe.

Using this measure, well-known conversion factors permit the energy obtained from different sources to be easily compared. While this approach doesn't take into account the varying efficiencies of different sources like oil and hydroelectricity, it does provide a well accepted standard for general comparison.

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We will first examine each of the energy categories separately, applying the development parameters that seem most appropriate to each. For each component I will define as clearly as possible the factors and parameters I have considered in building its scenario.

This will allow you to decide for yourself whether my assumptions seem plausible. We will then combine them into a single global energy projection. Once the energy picture has been established we will explore the effect the projected changes in energy supply may have on the world population.

Once that baseline has been developed, we will incorporate the probable effects of ongoing ecological damage to arrive at a final projection of human numbers over the next century. The timing of significant energy-related events and rates of increase or decrease of supply were chosen through careful study of the available literature.

In some cases different authors had diverging opinions on these matters. To resolve those situations I have relied on my own analysis and judgment.

Rockefeller Commission on Population and the American Future - Intro and Chapter 1

As a result the model has remained open to the influence of my personal biases. I make no apology for this; such scenarios always reflect the opinions of their authors, and it is best to be clear about that from the start. Nevertheless, I have made deliberate efforts throughout to be objective in my choices, to base my projections on observed trends in the present and recent past, and to refrain from wishful thinking at all times.

The WEAP model presents a global aggregation of the effects of energy and ecological factors on world population.

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Although there is some discussion of regional or national differences which would be expected to have a profound impact on the course of events in those placesthe model does not directly incorporate such influences.

While you may see this lack of granularity as a shortcoming, the paper is intended to give a higher level view. Its purpose is to establish a broad conceptual framework within which such regional disparities may be understood.

This paper will not present any prescriptive measures. The analysis is intended solely to clarify a "most likely" future scenario, based purely on the situation as it now exists and will probably unfold.

Population Viability Analysis, Beissinger, McCullough

You will not find any specific suggestions for what we ought to do, or any proposals based on the assumption that we can radically alter the behaviour of people or institutions over the short term.

While the probability of such changes will increase if the global situation shifts dramatically, such considerations would introduce a level of uncertainty into the analysis that would make it conceptually intractable. The same constraint holds true for new technologies.

You will not find any discussion of fusion or hydrogen power, for example. Energy Component Models Oil The analysis of our oil supply starts from the recognition that it is finite, non-renewable, and subject to effects which will result in a declining production rate in the near future.

This situation is popularly known as Peak Oil. The key concept of Peak Oil is that after we have extracted about half the total amount of oil in place the rate of extraction will reach a peak and then begin an irreversible decline.Methodology.

The analysis in this paper is supported by a model of trends in energy production. The model is based on historical data of actual energy production, connected to projections that are drawn from the thinking of various expert energy analysts as well as my own interpretation of future directions.

The Guttmacher Institute is a leading research and policy organization committed to advancing sexual and reproductive health and rights in the United States and globally.

31 West 27th Street 12th Floor New York, NY FAX heartoftexashop.com FINAL Project Report NYC Full Service Grocery Store Analysis. UNFPA, the United Nations Population Fund, works to deliver a world where every pregnancy is wanted, every childbirth is safe and every young person's potential is fulfilled.

Population viability analysis represents a “fine filter” approach to conservation planning compared to the coarse filter approach, which posits that the majority of species can be protected by conserving examples of natural vegetation communities (Noon et al.

). Population viability analysis represents a “fine filter” approach to conservation planning compared to the coarse filter approach, which posits that the majority of species can be protected by conserving examples of natural vegetation communities (Noon et al.

).

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