Today we commemorate the death of the last known Thylacine (also called the Tasmanian Tiger or Tasmanian Wolf) in 1936. It is national threatened species day, held each year on 7th September.
The Thylacine once lived all across Australia and New Guinea and was Australia’s largest predator, but was wiped out from the mainland around 3500 years ago; soon after the dingo was introduced and human (Aboriginal) populations grew in size and started using more sophisticated technology, explain Mark Letnic and others in a recent paper. Thylacines survived in Tasmania where there were no dingoes until the early 1900s, when they were wiped out by hunting (a bounty was even offered by the Tasmanian Government and the Van Diemen’s Land company on their heads).
Without the integral role of top-order predator being filled by the Thylacine, dingoes now play an integral role in maintaining healthy balanced ecosystems in many parts of Australia, keeping the populations of herbivores and smaller predators (including cats and foxes) in check (more will follow about this topic a later post).
To commemorate Threatened Species Day, the Australian Network for Plan Conservation released a list and slideshow today of 21 of Australia’s most threatened plants (scroll to the bottom of this post for the slideshow).
According to the Network, the general public is typically aware that many of Australia’s animals, like the Tasmanian Devil and the Hairy-nosed Wombat, are threatened with extinction. But they are often not aware that hundreds of Australian plant species face extinction. More than 40 Australian Plant Species have become extinct since European settlement and over 1000 species are currently considered likely to become extinct within our lifetime unless something is done to reverse their decline.
In our lab meeting this morning we were all asked to come with a little spiel about our favourite threatened species. The species discussed varied from the Banksia Montana mealybug (a completely new species, in a completely new genus in the family Pseudococcidae) – a little critter that lives on the endangered Banksia Montana, known from only a few populations from two mountain peaks in the Stirling Ranges, Western Australia. It’s host plant’s range has shrunk, and continues to be threatened by synergistic effects of Phytophthora dieback and fire. On the top of bluff knoll in the Stirling Ranges only seven adult plants survive, and only one of them has the mealy bug, whose closest relative is a mealybug found in Hawaii. With it, this miniscule little animal may well drop off the plane of existence. Some translocations of the Banksia have been successfully performed, but we are a long way from knowing whether there is a way to ensure the survival of this species, and if so how it could be done with generally limited funds and other challenges.
Another lab member discussed the critically endangered pine featherflower, of which only a thousand remain in the wild, in privately owned agricultural land in the highly cleared Western Australian Wheatbelt. 100 of these elegant have been cultivated and now grow in Kings Park, and there are seeds of this species in storage (an ‘insurance policy’ against the extinction of plants in the wild). Both populations of this species are now fenced off from grazing stock, so its main threats are the taxon’s narrow distribution, insecurity of tenure, weeds and poor rainfall.
Other mentions included the endangered green and golden bullfrog (http://www.environment.nsw.gov.au/resources/threatenedspecies/08468tsdsgreengoldenbro.pdf), a celebrity species at the 2000 Sydney Olympics (we’ll see if the frog is still around the next time the Olympics come our way), the plant-louse Acizzia veski and the black-footed ferret (a fascinating ecosystem engineer that has just returned from the brink of extinction – there are only about 1000 of these left in the wild, all of which were bred in a captive breeding program. Unfortunately captive breeding programs are rarely so successful).
I presented Tetratheca aphylla subspecies aphylla. While there are other subspecies of this species in a very limited few other locations, this subspecies grows only on Helena-Aurora range; a stunning banded ironstone formation surrounded by woodland and sandplain in the Great Western Woodlands (my study area). It is one of 6 identified species that grow only on that range (a very small area really), and 12 priority species that occur on this biogeographical ‘island’. These species are threatened by mining, which has been approved to essentially remove a large part of the range for the production of a fraction of the iron ore that is exported from the Pilbara every day (i.e. an insignificant contribution to the state’s economy).
The list of all threatened species would be very, very long. In 2008 there were almost 20,000 threatened species on the International Union for the Conservation of Nature’s (IUCN) Red List, but this is a gross underestimate, as the Red List has only assessed 4% of all described species; many of these are deemed ‘data deficient’ (there isn’t enough information to judge whether or not they are threatened), and the vast majority of species are yet to be even described. And some species that may be ok under the current climate may not be able to survive climate changes, particularly when they act synergistically with other threatening processes.
For a species that is recognised as being in danger of extinction, unfortunately there is a lot of difficulty in having it listed as threatened (a broad category which encompasses vulnerable, endangered, and critically endangered classifications). The difficulties include the paucity of knowledge that is required to make such a determination, a great deal of bureaucratic red tape (such as that between the federal and state or regional-level lists that exist in many countries), insufficient funding to support the listing process and the actions which are required as a result of a species being listed, and politics. A couple of lab members commented that no new threatened species were listed in the USA in the ten years of the Bush administration ‘for political and economic reasons’, including the Greater Sage Grouse. The IUCN currently has more threatened species listed in the US than the US does itself, and waiting lists for listing are long. Nevertheless, threatened species listing can aid the plight of a species (although not necessarily guarantee its survival) by giving impetus for improved conservation measures, research, and legal protection.
While there are a suite of ecological, utilitarian, legislative and moral reasons for which the extinction of a species must be averted where possible (more on this in another post), in our commemoration of threatened species we must not forget the critical complement to threatened species conservation – looking after ecosystems and the multi-layered diversity that they contain before they become threatened, for it is much easier and cheaper to conserve things before they begin the downward spiral, and such action bears many complementary benefits and has a far greater likelihood of success.
The critically endangered greater sage-grouse inflating its neck-sacs for a courtship display; apparently if it’s endangered status was formally recognised, it would have the potential to significantly affect the oil and gas industry which is currently fragmenting and degrading its habitat. Photo from http://www.endangeredspecieslawandpolicy.com/
Sustaining Ecology 