Causes of today's mass extinctions

Causes of today's mass extinctions.pdf Causes of today's mass extinctions.pdf
Size : 74.317 Kb
Type : pdf

Causes of today's mass extinctions
If we are to effectively plan conservation action that will protect and restore the diversity of life, we need to think about the causes of today’s mass extinctions.
Aldo Leopold was the greatest American conservationist of the twentieth century. His insights more than half a century ago are still relevant today. One of his tree-blazes reads:

One of the penalties of an ecological education is that one lives alone in a world of wounds….An ecologist must either harden his shell and make believe that the consequences of science are none of his business, or he must be the doctor who sees the marks of death in a community that believes itself well and does not want to be told otherwise.
In recent years, ecological and historical researchers have greatly improved our understanding of ecological damage. Even in the best-protected areas, such as National Parks and wilderness areas which are ungrazed by domestic livestock, pre-existing damage may continue to fester.
The end point of human-caused damage to ecosystems is today’s extinction crisis — death.
The Rewilding Institute, the Wildlands Network, and cooperating groups now categorize the damage to our planet in the following ways:
1.  Direct killing of species
2.  Loss and degradation of ecosystems
3. Fragmentation of wildlife habitat
4.  Loss and disruption of natural processes
5..Invasion by exotic species and diseases
6.  Poisoning of land, air, water, and wildlife
7.  Global climate change
Each wound has more than one cause, and many of the causes contribute to more than one wound. The overall impact of these wounds is greater than their sum, and they are highly synergistic.
Among the leading causes of these wounds are overhunting, overfishing, and trapping (including poaching); predator and “pest” extermination (shooting, poisoning, trapping); removing native animals and plants for collectors; agricultural clearing; livestock grazing; livestock fencing; logging and fuelwood collection; mining; energy exploitation; industrial recreation (ski areas, resorts, golf courses, etc.); off-road vehicle recreation; urban, suburban, and semi-rural subdivisions sprawl; agricultural and forestry biocides; intentional or accidental releases of non-native species; road building; fire suppression; dam building; irrigation diversions; groundwater depletion; channelization of streams and rivers; air, water, and land pollution; and human overpopulation (which, after all, is the fundamental cause).

1. Direct Killing of Species

During the preceding five hundred years or so, indigenous animals — especially fish, carnivores, large ungulates, keystone rodents, and birds — have become extinct, regionally extinct, or greatly reduced in number by commercial fishing and seabirding; whaling; subsistence hunting and game-hogging; market hunting; trapping; predator and “pest” control; and collecting.

2. Loss and Degradation of Ecosystems

For almost four hundred years ecosystems, throughout the world, have been degraded and even destroyed by agricultural clearing, logging, grazing by domestic livestock, burning, elimination of keystone species, mining, wetland draining, urbanization, suburbanization, exurban sprawl, subdivision of land into smallholdings, bottom trawling, dams, water diversions, groundwater pumping, channelization, industrialisation, and oil and gas development.

3. Fragmentation of Wildlife Habitats

Fish and other wildlife habitat have been fragmented by all of the factors causing ecosystem loss and degradation, and by road and highway building, off-road vehicle (ORV) use, pipelines, power lines, and peri-urban smallholdings.

4. Loss and Disruption of Natural Processes

Vital ecological and evolutionary processes — especially fire, hydrological cycles, and predation — have been disrupted and even eliminated by logging, grazing, fire control, animal trapping, dams and other flood control measures, and killing of highly interactive species — especially large carnivores.

5. Invasion by Exotic Species and Diseases

Aggressive and disruptive exotic species — plants, animals, and disease organisms and vectors — have:
1. invaded,
2. escaped from cultivation, or
3. been deliberately introduced, threatening ecosystems and the survival of many native species.
In many instances these invasive species have completely swamped the native indigenous species due to the fact that they have no local, natural enemies.

6. Poisoning of Land, Air, Water, and Wildlife

Farms, feedlots, mines, factories, smelters, power plants, agricultural and public-health biocides, automobiles, oil pipelines and tankers, and urban areas have spread heavy metals, toxic wastes, and chemicals in the air, land, and water, harming species and ecosystems.
Of growing concern is the growing proliferation of litter along roadsides, on open ground, in our rivers and in the oceans which is poisoning and killing wildlife when it is ingested.

7. Global Climate Change

Since the beginning of the industrial era, air pollution from cars, power plants, smelters; carbon dioxide releases from logging; and other human activities have increased the percentage of carbon dioxide, methane, and other greenhouse gases, leading to rises in the sea level, and changes in temperature and precipitation.
Of particular concern is the amount of greenhouse gases which can be attributed to the production, processing, transport and marketing of meat and animal products for human consumption. It has been determined that over 50% of all greenhouse gas emissions can be attributed to these sources.

Healing the Damage Goal-Setting

A hallmark of recent conservation efforts is ecological restoration. Unfortunately, much of what is called ecological restoration falls far short of the mark. Michael Soulè warns against “restoration” that seeks only to put back the process, but not the community. He writes that “it is technically possible to maintain ecological processes, including a high level of economically beneficial productivity, by replacing the hundreds of native plants, invertebrates and vertebrates with about 15 or 20 introduced, weedy species.” Continental Conservation cautions that “process and function are no substitute for species.” Without native species, the land is domesticated or feral, not wild. Unmanaged land without native species is not a wilderness, but a wasteland.
Much restoration has focused on small sites — a patch of natural grassland, a salt marsh, a suburban stream. These efforts are vital for protecting and recovering imperilled species with narrow habitat requirements, but we also need to do restoration on a landscape or continental level. Less than landscape-scale restoration produces “ecological museum pieces — single representatives of communities that, although present because of unusually large restoration and maintenance investments, do not exist in any ecologically meaningful way.” (Continental Conservation.) A medical analogy would be that of keeping a patient alive on life-support indefinitely and at great expense when there is no hope that she will ever be able to survive on her own.
To rewild the Earth, we must have a vision that is bold, scientifically credible, practically achievable, and hopeful. The practically achievable part requires specific goals and action steps — organized to heal the specific wounds.
Although ecological restoration is essential for an overall conservation strategy, it is painfully clear that, in the twenty-first century, natural areas and wildlife will continue to be imperilled by human activities. A frontier approach to exploiting Nature still rules in much of Africa, Canada, the United States, Mexico, and Central America. Restoration will come to naught if further wounding of the land is not stopped. Therefore, each of the seven healing-the-damage goals is twofold:
1. to prevent additional damage, and
2. to heal existing damage.

Goal 1: Permanent protection of extant indigenous species from extinction or endangerment, and recovery of all species native to the continent except those already extinct.

Goal 2: Permanent protection of all habitat types from further degradation and loss, and restoration of degraded habitats.

Goal 3: Protection of the land from further fragmentation, and restoration of functional connectivity for all species native to the region through wildlife migration corridors.

Goal 4: Restoration and the permanent protection of the functioning of ecological and evolutionary processes.

Goal 5: Prevention of the further spread of exotic species (including pathogens), and elimination or control of exotic species already present.

Goal 6: Prevention of the further introduction of ecologically harmful pollution into the region, and the removal or containment of existing pollutants.

Goal 7: Management of landscapes and wildlife to provide opportunities for adaptation and adjustment to climate change.

These are heady goals. With over seven billion people living on Earth, they can be gained in the near term only in part or even in small part for much of the world. They apply not only to natural area networks in regions still wild or suitable for major restoration, but also to areas which have already been degraded by human activities.
Moreover, these goals are comprehensive, and should be embraced in principle by the whole conservation movement and land managers. No one organization can tackle them all, but all who love Nature should adopt them as overarching goals for twenty-first-century conservation. They must be carried out on local, regional, and continental scales.
Most people have the false notion that the conservation and restoration of natural areas and ecosystems can only be tackled by governments, large corporations and large NGOs. If we are going to wait for governments, official conservation organisations and NGOs to tackle the problems, nothing will be done and we can then expect the situation to deteriorate even further.
It is amazing what a small group of people, or even individuals, can accomplish if they are prepared to sacrifice some of their time towards restoring and conserving a wildlife habitat near their homes or in their suburb.
Perhaps one of the biggest contributions that individuals, or families, can make towards the restoration of our planet is to adopt a vegan lifestyle. 

Veganism is a way of life which embraces the following principles:

Vegans do not consume or use any animal product.
Vegans are compassionate towards all living creatures and respect their right to life and to be free from harm.

In addition to embracing a vegan lifestyle, people must recognise that all species, both animate and inanimate, fill important niches in the “web of life” and that each is essential for the well-being of the whole ecosystem and the biosphere.

(Part of this article was adapted from Rewilding North America by Dave Foreman (chapters 5, 6, and 7). )