4.4 Conservation biology

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From the course by National Research Tomsk State University

Ecology: from cells to Gaia

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National Research Tomsk State University

Ecology: from cells to Gaia

56 ratings

This course presents the principles of evolution and ecology for citizens and students interested in studying biology and environmental sciences. It discusses major ideas and results. Recent advances have energised these fields with evidence that has implications beyond their boundaries: ideas, mechanisms, and processes that should form part of the toolkit of all biologists and educated citizens. Major topics covered by the course include fundamental principles of ecology, how organisms interact with each other and their environment, evolutionary processes, population dynamics, communities, energy flow and ecosystems, human influences on ecosystems, and the integration and scaling of ecological processes through systems ecology. This course will also review major ecological concepts, identify the techniques used by ecologists, provide an overview of local and global environmental issues, and examine individual, group and governmental activities important for protecting natural ecosystems. The course has been designed to provide information, to direct the student toward pertinent literature, to identify problems and issues, to utilise research methodology for the study of ecology and evolution, and to consider appropriate solutions and analytical techniques. Needed Learner Background: general biology and a good understanding of English. This course has the following expectations and results: 1) covers the theoretical and practical issues involved in ecology and evolution, 2) conducting surveys and inventories in ecology, 3) analyzing the information gathered, 4) and applying their analysis to ecological and conservation problems.

From the lesson

Module 4. Population Ecology and Evolution

In this final module, we will explore the possibility of a new ecology by exploring the concept of sustainability, evaluating the human impacts on ecosystems and providing some solutions for nature conservation. Finally, we will see how to organise a citizen science event, called Bio-blitz, which can improve the scientific knowledge of our planet and, at the same time, rise the ecological awareness of citizens.

4.4 Conservation biology6:06

Meet the Instructors

Roberto Cazzolla Gatti
Ph.D., Associate Professor in Ecology and Biodiversity
Biological Diversity and Ecology Laboratory, Bio-Clim-Land Centre of Excellence, Biological Institute

Hi learners! Welcome to the 19th lesson on my course,

Ecology: from cells to Gaia.

Today, we will talk about conservation biology.

Conservation is the science concerned with increasing

the probability that Earth's species and communities or,

more generally, its biodiversity will persist into the future.

Biodiversity is, at its most basic,

the number of species present,

but it can also be viewed at smaller scale.

For instance, as a genetic variation within population,

and at larger scale as a variety of community types present in a region.

About 1.8 million species have been so far named,

but the real number is probably between three and 30 million.

The current observed rate of extinction may be as much as

100,000 times the background rate indicated by the fossil record.

A species may be rare in the sense that

its geographic and/or habitat ranges are small or in the sense that local populations,

even where they are occur, are small.

Many species are naturally rare,

but just by virtue of their rarity,

species are not necessarily at risk of extinction.

However, other things being equal,

it will be easier to make a rare species extinct.

Some species are born rare,

others have rarity thrust upon them as a result of action of humans.

The principal causes of decline are overexploitation,

habitat degradation, and the introduction of exotic species.

Overexploitation occurs when people harvest

a population for food or trophies at a rate that is unsustainable.

Human beings adversely affect habitat in

three ways: a proportion of available habitat may simply be destroyed

or it may be degraded by pollution or it may be

disturbed by human activities to the detriment of some of its occupants.

Human-caused introduction of exotic species,

which may occur accidentally or intentionally,

have sometimes been responsible for

dramatic changes to native species and natural communities.

Release of a gene may confer no immediate advantage

but could turn out to be well-suited to change environmental condition in the future.

Small population to have loss rare alleles to genetic drift have less potential to adapt.

A more immediate potential problem is inbreeding depression.

When populations are small,

there is a tendency for individuals breeding with one another to

be related and this may lead to reduction in fertility,

survivorship, growth rate, and resistance to disease.

A given population may have been reduced to

a very small size by one or more of the processes described before,

and this may have led to an increase in frequency of mating among

relatives and the expression of deleterious recessive alleles in offspring,

leading to reduced survivorship and fecundity,

and causing the population to become, still, smaller.

This is the so-called extinction vortex.

Much of conservation biology is a crisis discipline

concerned with the small population in immediate danger of extinction.

A high level of uncertainty governs the dynamics of small population,

whereas large population can be described as being governed by the law of averages.

Three kinds of uncertainty or variation can be identified that are of

particular importance to the fate of

small population: demographic, environmental, and special.

Moreover, loss of habitats frequently result not

only in a reduction in the absolute size of a population,

but also the division of the original population into a number of fragments.

Population viability analysis, a simulating modeling tool,

can be used to estimate the minimum population size of

a particular species that should ensure its persistence with an acceptable probability.

For example, greater than 90% for a reasonable period,

for instance, 100 years.

Armed with such information,

managers can work out the best approach to guard against extinction; for instance,

supplementary feeding, predator control,

one or more reserve of appropriate size, etc.

Given limited funds to purchase protected areas,

it is important to devise priorities so they can

be evaluated systematically and chosen with care.

We know that biotas of different location vary in species richness,

the extent to which the biota is unique,

and the extent to which the biota is endangered.

One or more of these criteria could be used to prioritize potential area for protection.

The principles of island biogeography theory provide

some clues about the most appropriate shape and disposition of protected areas.

The selection of a natural cover reserves to optimize the protection of

biodiversity can be performed on the basis of complementarity,

selecting at each step the site that is most

complimentary to those already selected in terms of the biodiversity it contains,

or irreplaceability, defined in terms of the likelihood of

an area being required to achieve specified conservation targets.

Predicted change to patterns of temperature and rainfall

around the world have important implication for conservation biology.

Changes to environmental conditions will affect

the size and location of habitable areas of species,

whether or not they are currently at risk of extinction.

Moreover, natural reserves may turn out to be in the wrong places.

Models of global climate change can be used by ecologists to save more species and

communities when planning for the conservation of

individual species or designing reserve networks.

So at the end of this lecture,

I have some question for you as usual.

The first one is, how would you define the aims of conservation biology?

For you, are zoos and botanical gardens useful in nature conservation?

And the last, how can the loss or introduction of a single species have

conservation consequences throughout the world ecological community?

So thank you for your attention.

I'll see you at the last lesson.

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