The International Union for Conservation of Nature (IUCN) has 26,500 species on its ‘red list’ of species threatened with extinction. Some argue that these losses are part of a huge global biodiversity depletion that represents a crisis equalling or surpassing climate change. Others, while acknowledging that worldwide biodiversity is decreasing, are not so sure there is a crisis.
Scientists generally agree that globally we are losing species faster than they are being created. There has always been ‘natural’, low rate extinction and there have been five ‘mass extinctions’ during each of which over 75% of earth’s species were lost. Many believe this is the sixth great extinction under way. Even relatively common species are fast losing populations all over the planet. We are polluting and destroying the habitats of all plants and animals, introducing new predators and removing food sources. We do this directly by building, mining, manufacturing and farming, and indirectly through carbon dioxide production and climate change.
Most, not all, are agreed that a world of diverse species and landscapes enhances our lives immeasurably. Not only aesthetically: abundant and varied flora and fauna provide us with all sorts of services essential to human survival from macro scale water, nutrient and carbon dioxide cycles to the microbial activities that keep our bodies functioning and plentiful sources of food and medicine.
More debated is to what extent species richness is diminishing and whether the extent to which it is matters. For an increasing number of ecologists, the view of everything disappearing is too simple. Although the overall trend is down, species diversity is often stable or increasing locally, particularly in confined areas like islands. Alien species have moved in and adapted to new habitats, mostly living alongside native species that are also adapting to new neighbours and changing environments. New inhabitants acquire characteristics different from their ancestors and become new varieties, and eventually other species. New neighbours make new hybrids.
It is also argued that this upheaval in biodiversity could be good thing. That previous mass extinctions have resulted in eventual flourishing of new species. Many of today’s lush forests were farmland centuries ago: nature bounces back. The counter is that if the species pool is too diminished, flourishing again will take millennia: new species do not spring from thin air, they are newly adapted descendants of surviving species.
Meanwhile we do live on an impoverished planet. Even if species numbers are up locally. The number of species is not the only indicator of biodiversity. For one thing, new species now appearing in man-made habitats tend to be short-lived creatures with short generation spans, that can evolve quickly. We will miss the animals further along the evolutionary path, like mammals, that will take longer. More important, while the number of species in relatively intact ecological communities is stable or increasing, these communities are becoming more homogeneous—less diverse.
There is hope that with increased awareness of the importance of biodiversity and the value of natural systems, and new techniques from biotechnology together with the resilient adaptability of nature, some of the diversity we have lost can be restored within decades rather than millennia .
Target 12 of the UN Strategic Plan for Biodiversity set up in 2011 aims to prevent extinction and improve or sustain the conservation status of known threatened species by 2020. The action they take depends on the species and reasons for its threatened status, but protection measures include wildlife reserves, diversity protection laws, and reintroduction of species to habitats they have been pushed out of.
There have been some successes: recently the Fin Whale and Mountain Gorilla have improved in conservation status. But the target gets harder because the IUCN are finding more threatened species faster than UN efforts are taking them off the danger list—not necessarily because more species are threatened but because more species are being assessed for status. To date 96,951 species have been assessed, a fraction of the 1.7 million species that have been recorded. There are thought to be possibly up to 100 million species on the planet.
Now that the cost of sequencing genomes has dropped dramatically, a new area of ‘genomic conservation’ holds the prospect of preventing, even reversing some of the species losses. Revive and Restore brings conservation groups together with academic and commercial laboratories using biotechnology to develop solutions. It can also bring funding.
New conservation tools and practices include biobanks that store biological samples and genetic information that can be used for research and restoration of endangered species. Amongst other things, genetic information facilitates tracking species through DNA left in the environment and provides insights for captive breeding programs and translocation of animals. It can also enable advanced reproductive techniques including cloning, and genomic engineering to confer adaptive capabilities.
Public awareness is leading to less hunting, lower use of harmful chemicals and more wildlife friendly practices on farms, in gardens and at roadsides. ‘Rewilding’ and reforestation are becoming popular in many parts of the world. People are appreciating the value of verdant spaces, flowers, animals and forests for wellbeing.
Dynamism and change are the norm in nature. Ecosystems, the result of chance and accident as species and conditions meet and change, are not stable finite systems as we once thought. They are constantly changing and adaptable. So new landscapes will be different from old ones, but they do not all invariably have to be poorer. While the pressure on land for agriculture and urbanisation will increase everywhere, public attitude will be a key driver of policy protecting diversity.
- At November 2018
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