While the causes of endangerment are relatively easy to understand, the ultimate or underlying factors are often far more complex and difficult to address. An introduction to these issues and how to resolve them is provided in this unique collection of case studies of animal species that have been pushed to the brink of extinction. Each case study provides the following information: Conservationists are increasingly recognizing that the ultimate causes of extinction are primarily socio-economic and political, yet biological approaches to recovery continue to dominate.
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This article has been cited by other articles in PMC. Abstract Infectious disease, especially virulent infectious disease, is commonly regarded as a cause of fluctuation or decline in biological populations.
However, it is not generally considered as a primary factor in causing the actual endangerment or extinction of species. We review here the known historical examples in which disease has, or has been assumed to have had, a major deleterious impact on animal species, including extinction, and highlight some recent cases in which disease is the chief suspect in causing the outright endangerment of particular species.
We conclude that the role of disease in historical extinctions at the population or species level may have been underestimated. Recent methodological breakthroughs may lead to a better understanding of the past and present roles of infectious disease in influencing population fitness and other parameters.
Background Although lethal epi- or panzootics are obvious risk factors that can lead to population fluctuation or decline in particular circumstances, infectious diseases are seldom considered as potential drivers of extirpation or extinction—that is, of the complete loss of all populations or subunits comprising a given biological species.
For example, in conservation biology, infectious disease is usually regarded as having only a marginal or contributory influence on extinction, except perhaps in unusual circumstances e. In their examination of instances of critically endangered species listed by the IUCN International Union for Conservation of Nature as allegedly threatened by infectious disease, Smith et al.
Although this record should improve with increasing awareness of the effects of infectious diseases on wildlife, as this paper illustrates progress has so far been slow. Both of the authors of this paper are primarily concerned with mammals, which is the group that will receive the bulk of attention here.
However, at the pragmatic, data-gathering level, the issues concerned with properly accounting for and evaluating the effects of infectious diseases on natural populations differ little from one phylogenetic grouping to another.
First, narrowing down extinction events or even catastrophic population declines to single causes is almost always problematic. In most real cases, extinction is multicausational, even if one cause can be identified as being predominantly responsible [ 5 ].
Habitat fragmentation and climate change are currently regarded as the leading prime movers behind most instances of extreme endangerment, to which other stressors such as pollution, invasive competitors, and so forth, might be of greater or lesser importance in particular circumstances.
Disease, however, is rarely mentioned as a possible contributing factor in such contexts but see [ 6 ]. Another difficulty is lack of knowledge about pathogen diversity and susceptibility in wildlife.
In the absence of sufficient means of detection and characterization, it is difficult to assess or to give quantitative expression to the degree to which pathogens might influence population decline or extinction.
Thus it has been estimated that only a small fraction of bacterial diversity has been identified at even the most basic systematic level. For example, bat viruses have only recently begun to be described systematically, even though many chiropterans are known vectors of numerous zoonotic diseases and corporately represent the second largest grouping by species richness of mammals after rodents [ 89 ].
A similar lack of knowledge affects our understanding of parasites and fungi that affect wildlife. The foregoing difficulties are compounded when one considers that, unless a species is studied extensively during and up to the actual extinction event affecting it, all extinction studies are retrospective.
Retrospective investigation of losses in which disease is possibly implicated is often severely hindered by limitations in the number and quality of samples available for study, as well as the inability to satisfy Koch's postulates—especially if both host and pathogen became extinct simultaneously [ 10 ].
Performing isolation, reisolation, and reinfection experiments to directly establish that a particular pathogen was indeed the causative agent behind a given infection is either very difficult or impossible to do retrospectively.
Isolation and recreation of the H1N1 influenza A virus [ 11 ], for example, were performed by sequencing from extractions derived from individuals thought to have died of the disease in WWI, not by directly isolating the infectious virus from tissues as would be required to formally comply with Koch's postulates.
Forensically, decay, degradation, and chemical changes in DNA post mortem produce severe methodological challenges to retrieving and accurately determining sequences [ 13 ].
For example, relatively abundant mitochondrial DNA is generally easier to retrieve from fossils or historical samples than lower copy per cell nuclear DNA.
Pathogen nucleic acids are generally even lower copy than host DNA sequences in a given extraction. These and other factors reviewed here may help to explain the paucity of conclusive studies of disease-mediated extinction, except in the very few instances in which sampling and methodological roadblocks could be overcome.
Nonetheless, in favorable circumstances it should be possible to genetically analyze ancient pathogens with sufficient accuracy to make the endeavor worthwhile, especially because next-generation sequencing methods are beginning to make such endeavors ever more feasible [ 14 — 18 ].
Why should the possible role of infectious disease in endangerment and extinction be regarded as a critical issue in modern conservation?
Whether or not disease was ever a major cause of extinction in the fossil record [ 19 ], in our times it plays an acknowledged but perhaps underestimated role.
Pathogen-driven population declines have been identified in a wide array of invertebrate and vertebrate taxa cf.Infectious Disease, Endangerment, and Extinction aﬀecting their endangerment, the num ber actually lost to t he.
distem per in black-foot ed . Endangered animals: a reference guide to conflicting issues User Review - Not Available - Book Verdict. Reading and Miller (Prairie Night: Black-Footed Ferrets and the Recovery of Endangered Species) are conservation biologists who present 49 case studies of endangered animals.1/5(2).
After the black-footed ferret population was decimated by disease, biologists determined that the remaining wild ferrets were not a viable breeding population. The last 12 ferrets were captured and combined with 6 ferrets already in captivity to bring the world total to 18 ferrets, all in captivity, in May 24, · Endangered Species Essay; Endangered Species Essay.
Essay on Endangered Species.
Because of man’s desire to expand and conquer their surroundings, there are animals and plants that are on the brink of extinction that will not be around for our kids and future generations to enjoy The Endangered Species Act Introduction: Long-term. The Gems Welcome to The Gems’ Essay! We combined groups 10 and 12 to form our group.
For, our essay, we researched how technology can help to save endangered species. 2 | P a g e Introduction According to a mathematical model developed for extinction, % of all species that researchers can determine the reason for their .
black footed ferret habitat description And Food chain. Where do black footed ferrets live? Consider each animal gets its own biome regardbouddhiste.com habitat range of black footed ferrets was once vastly as 40 million hectares but then quickly dropped to around , ha by thes.