In the last 200 years about 110 species of plants have gone extinct in Australia alone. 209 species are listed as critically endangered and could soon disappear. Unlike critically endangered animals, which are notorious to breed or behave in captivity as we want them to, we can take action right now and save most, if not all, of these endangered plants. How? It’s quite simple – just plant more of them!
Persoonia nutans is an example of an endangered species. This species was once widespread across Sydney, Australia, but is now restricted to a few populations. Image source: www.environment.nsw.gov.au
The idea may sound simple but it is actually based on quite a long history of scientific research and a more recent history of mathematical modelling. In ecology there is a debate called neutrality versus the niche and it is a debate about the abundance and diversity of species on our planet. In very basic terms, those on the niche side of the debate argue that species are found where they are found because they are adapted to a particular environment, and are better at capturing limited resources than their neighbours/competitors in that environment. Those on the neutrality side of the debate, on the other hand, argue that it is more to do with probability and chance. Abundant species are abundant because there are just more of them to begin with and they have a higher probability of filling vacant space than rare species.
Neutral theory can be used in conservation science to explain how some species go extinct. There are few individuals within rare and endangered species, this is why they are rare and endangered in the first place. Therefore there is a high probability they will go extinct because they have a low chance of filling any vacant space in the environment. How do you increase their chances of survival? Simply by increasing their numbers.
We have actually been doing this for a number of years and chances are you have actually participated in this conservation strategy. The most well-known case is the Wollemi Pine. In 1994 the Wollemi Pine was discovered in the Blue Mountains, west of Sydney. It is a prehistoric tree, with ties to fossils going back to the mid-Cretaceous (90 million years ago), but extremely rare with about 100 individuals restricted to a few small gullies. Knowing the vulnerability of the species, botanists almost immediately embarked on breeding more and more individuals. Now there are hundreds of Wollemi Pines all over Sydney, Australia and, indeed, the world. (http://www.wollemipine.com/index.php)
The Wollemi Pine growing in its natural habitat. Image source: www.rbgsyd.nsw.gov.au
Increasing individual numbers is the easy part. The harder part is where to put them. One of the leading causes of species extinction is habitat degradation and land clearing. These two processes are basically the removal of space for plants (and animals) to exist. Land clearing is the preferential removal of some plant species (e.g. rainforest) for other species (e.g. wheat, corn, sugar, pasture etc). Habitat degradation is the change of a set of physical and chemical parameters for a different set of parameters that the original species can no longer tolerate. Either way, apart from land reclamation, remediation, or turning farmers into diehard greenies, the space that was once available for the threatened or endangered plant is gone. New space needs to be found.
As with the example of the Wollemi Pine, a controlled breeding program can be undertaken and members of the public can plant endangered species in their backyards. But the government can also make much better use of a lot of empty space in our cities and urban areas.
Take the images below from Kings Park Botanic Gardens in Perth, Western Australia. There is a space specifically dedicated to endangered and threatened species inside of the botanic gardens. This is an excellent area of conservation but why cannot those plants be planted in other areas of the park? For example, a roundabout just around the corner from the conservation garden is crowded with native species but none of them are endangered. Just outside the park, road verges and medium strips have a mix of native and exotic species all of which have been planted for their visual aesthetics.
Yes these plants look fantastic but what other function do they provide? Why not devote this precious space to the threatened and endangered plants? What about all of those other roundabouts, road verges, and medium strips that are just exotic grasses and weeds? Even other areas, such as golf courses or along the edges of parks and sporting fields, could be dedicated to endangered plants.
The idea of increasing numbers of individuals in endangered species and planting them everywhere we can does not address all of the issues with species loss (think ecosystem functioning, plant-animal interactions, etc). But it will ensure we no longer lose any more species to extinction. If it was good enough for the Wollemi Pine, then it should be good enough for all species.
The conservation garden at Kings Park Botanic Gardens, Perth, Western Australia, is a great example of a conservation program. But why must the endangered and threatened plants only be planted within the Botanic Gardens?
An example of an endangered plant in the conservation garden, Kings Park Botanic Gardens.
Exotic rose bushes on the road medium strip just outside of Kings Park Botanic Gardens, Perth, Western Australia. Although visually appealing, such spaces could be dedicated to growing endangered plants.
A mixture of native and exotic species on a road verge just outside Kings Park Botanic Gardens. Another example of a space that could be dedicated to growing and conserving endangered plants.
A roundabout within Kings Park Botanic Gardens just around the corner from the conservation garden. This roundabout looks fantastic with a number of native species. But none of the species are threatened or endangered. Imagine if every roundabout carried endangered and threatened plants.