CONSERVATION BIOLOGY AND RESTORATION

ECOLOGYChapter 55

Overview

Conservation biology integrates ecology (including behavioral ecology), physiology, molecular biology, genetics, and evolutionary biology to conserve biological diversity at all levels.

Restoration ecology applies ecological principles in an effort to return degraded ecosystems to conditions as similar as possible to their natural, pre degraded state.

Throughout the biosphere, human activities are altering trophic structures, energy flow, chemical cycling, and natural disturbance—ecosystem processes on which we and other species depend

By some estimates, we are in the process of doing more damage to the bio–sphere and pushing more species toward extinction than the large asteroid that may have triggered the mass extinctions at the close of the Cretaceous period 65.5 million years ago

Human activities threaten Earth′s biodiversity (Sect. 1)

Extinction is a natural phenomenon that has been occurring almost since life first evolved; it is the current rate of extinction that underlies the biodiversity crisis.

Humans are threatening Earth′s biodiversity.

Biodiversity short for biological diversity has three main components, or levels: genetic diversity, species diversity, and ecosystem diversity. All three are being decreased by human activity.

Genetic Diversity

Genetic diversity comprises not only the individual genetic variation within a population, but also the genetic variation between populations that is often associated with adaptations to local conditions

If one population becomes extinct, then a species may have lost some of the genetic diversity that makes microevolution possible. This erosion of genetic diversity is, of course, detrimental to the overall adaptive prospects of the species.

If we lose genetic resources that could potentially be used to improve certain crop qualities, such as disease resistance, through plant breeding.

Species Diversity endangered species as one that is “in

danger of extinction throughout all or a significant portion of its range

threatened species are those that are considered likely to become endangered in the foreseeable future.

To know for certain that a given species is extinct, we must know its exact distribution.

Ecosystem Diversity Because of the network of community

interactions among populations of different species within an ecosystem, the local extinction of one species

Each ecosystem has characteristic patterns of energy flow and chemical cycling that can affect the whole biosphere.

Some ecosystems have already been heavily impacted by humans, and others are being destroyed at an astonishing pace.

Biodiversity and Human Welfare Many species that are threatened could potentially provide

crops, fibers, and medicines for human use, making biodiversity a crucial natural resource.

The loss of these species would mean the loss of any possible medicinal benefits they might offer.

The loss of species also means the loss of genes. Each species has certain unique genes, and biodiversity represents the sum of all the genomes of all organisms on Earth.

Because many millions of species may become extinct before we even know about them, we stand to lose irretrievably the valuable genetic potential held in their unique libraries of genes.

Ecosystem services encompass all the processes through which natural ecosystems and the species they contain help sustain human life on Earth.

Four Major Threats to Biodiversity

Many different human activities threaten biodiversity on a local, regional, and global scale. : habitat destruction, introduced species, overexploitation, and disruption of “interaction networks” such as food webs.

Human alteration of habitat is the single greatest threat to biodiversity throughout the biosphere.

Habitat destruction may occur over immense regions.

Habitat fragmentation leads to species loss, since the smaller populations in habitat fragments have a higher probability of local extinction.

Introduced species, also called invasive, nonnative, or exotic species, are those that humans move, either intentionally or accidentally, from the species′ native locations to new geographic regions.

Introduced species that gain a foothold usually disrupt their adopted community, often by preying on native organisms or outcompeting them for resources.

Humans have deliberately introduced many species with good intentions but disastrous effects.

Overexploitation refers generally to the human harvesting of wild plants or animals at rates exceeding the ability of populations of those species to rebound.

Overexploitation refers generally to the human harvesting of wild plants or animals at rates exceeding the ability of populations of those species to rebound.

Species with restricted habitats, such as small islands, are also very vulnerable to overexploitation.

Ecosystem dynamics depend on the networks of interspecific interactions within biological communities.

Population conservation focuses on population size, genetic diversity,

and critical habitat (Sec. 2) Biologists focusing on conservation at the population and

species levels follow two main approaches—the small–population approach and the declining–population approach.

Small–Population Approach Conservation biologists who adopt this approach to deal

with conservation study the processes which cause very small populations to finally become totally extinct.

The key factor in this vortex is the loss of genetic variation which enables evolution.

Once the population reaches or dips below this minimum population size, it is highly unlikely that the species will be able to survive.

he chances of the survivability of the species can also be calculated by the effective population size. This formula determines the sex ratio of breeding individuals into the estimate of effective population size.

Declining-Population Approach This approach focuses on threatened and

endangered populations which are showing a downward trend.

The scientists solely use the the current trend to assume that the population will continue to fall at the same rate.

The declining-population approach emphasizes the environmental factors that caused a population to decline in the first place. In addition, there are steps to analyze and intervene for this approach.

Landscape and regional conservation aim to sustain

entire biotas (Sec. 3) landscape ecology of which ecosystem

management is part, is to understand past, present, and future patterns of landscape use and to make biodiversity conservation part of land–use planning.

The biodiversity of a given landscape is in large part a function of the structure of the landscape.

Some organisms thrive in edge communities because they have access to the resources of both adjacent areas.

The proliferation of edge species can have positive or negative effects on a community′s biodiversity.

Where habitats have been severely fragmented, the presence of a movement corridor, a narrow strip or series of small clumps of quality habitat connecting otherwise isolated patches, can be a deciding factor in conserving biodiversity.

Movement corridors also can promote dispersal and reduce inbreeding in declining populations.

Corridors are especially important to species that migrate between different habitats seasonally.

ll the effects of corridors are not yet understood, and their impact is an area of active research in conservation biology and restoration ecology.

Conservation biologists are applying their understanding of community, ecosystem, and landscape dynamics in establishing protected areas to slow the loss of biodiversity.

A biodiversity hot spot is a relatively small area with an exceptional concentration of endemic species and a large number of endangered and threatened species

Biodiversity hot spots are obviously good choices for nature reserves, but identifying them is not always straightforward.

Nature reserves are biodiversity islands in a sea of habitat degraded to varying degrees by human activity

Because human disturbance and fragmentation are increasingly common landscape features, the dynamics of disturbance, population dynamics, edges, and corridors are important in the design and management of protected areas.

Land use by humans may outweigh all other considerations and ultimately dictate the size and shape of protected areas.

Several nations have adopted a zoned reserve approach to landscape management.

A zoned reserve is an extensive region of land that includes one or more areas undisturbed by humans surrounded by lands that have been changed by human activity and are used for economic gain.

The key challenge of the zoned reserve approach is to develop a social and economic climate in the surrounding lands that is compatible with the long–term viability of the protected core area.

Restoration ecology attempts to restore degraded ecosystems to

a more natural state (Sec. 4) As humnas spread across the globe they brought

their toxins and there selfish ways by taken what they want and then throwing it away when there done with it.

Many ecosystems are tarnished and then abandoned by such humans leaving the area scard. Still nature has it ways where it naturally rebuilds itself and stablizing the ecosystem.

The larger the area the more time it takes for the area to be restored. The two key stategies of restoration ecology are bioremediation and augmentation of ecosystem processes.

Bioremediation is using living oragnisms like plants, fungi, and prokaryotes to detoxify the polluted area.

Where some plants are able to clean soil. Soil that has been contaminated with excess amount of metals from a mining site. Prokaryotes are the most common as they metablolize toxins and waste.

Biological augmentation is the strategy that uses organisms to add essential materials to the polluted ecosystem.

Encouraging growth of plants that thrive on porr rich soil speed help speed up the proccess. Since there are many diffrent types of ecosystems and because they are in constant flux restoration ecologist must be able to adapt in order to assure proper resoration.

Sustainable development seeks to improve the human condition

while conserving biodiversity (Sec. 5)

We as humans have to be able to understand the comlexity of ecosystems before we can begin to imagine to make the right decision to conserve such compexity.

Many scientist and ecologist have embraced the concept of sustainable development the long term prosperity of human societies and the ecosystems that support them.

The goal of this initiative is to define and acquire the basic ecological information necessary for the intelligent and responsible development, management, and conservation of Earth′s resources.

The research agenda includes studies of global change between climate and ecological processes; biological diversity and its role in maintaining ecological processes; and the ways  the productivity of natural and artificial ecosystems can be sustained.

Humans must begin to look towards a long term gain rather than short term where much more consequences exist in only looking at the short term gains.

Most humans live away from wild life not knowing how such life is being affected by there short term gains. But our behavior reflects remnants of our ancestral attachment to nature and the diversity of life the concept of biophilia that we introduced early in this chapter.

We evolved in natural environments rich in biodiversity, and we still have an affinity for such settings

By learning about the processes and diversity of life, we also become more aware of ourselves and our place in the biosphere.