Thursday, May 30, 2024

Extinction not inevitable

What is a Puteketeke (poo techie techie)? About 300,000 people worldwide now know because they voted to make it New Zealand’s bird of the century. Some Kiwi’s called foul (or should that be fowl) because of the influence of an American based talk show host who promoted himself as the Puteketeke campaign manager ruffling the feathers of many of New Zealand’s bird enthusiasts. The purpose of the contest was to highlight the plight of New Zealand’s birds, 82% of which are considered threatened with extinction. Should we consider a ‘plant of the century’ contest to highlight the plight of many of Australia’s threatened plants?

A not so highly publicised Australian report, published by the Invasive Species Council and authored by Carol Booth and Tim Lowe titled, Gone: Australian animals extinct since the 1960’s, profiles probable animal and some plant extinctions from the last 60 years or so. The report includes four likely plant extinctions but admits that plants are a difficult category. A 2004 study of plants designated extinct by the Australian Government or CSIRO found that of 228 species listed, 167 were either rediscovered or their status as a species questioned. As noted in the Extinctions report, plants often have persistent seedbanks which means that a species can be absent as a plant but survive in the soil for prolonged periods awaiting fire or some other germination cue.

A group of botanists led by Jennifer Silock reviewed a list of plants designated as extinct by the Australian Government. From that list they decided that Australia has two species that are almost certainly extinct, ten probables, twenty possibles, and seventeen still existing. They concluded that possibly three of seven plants listed as extinct had not been searched for thoroughly enough.

In 2016, in conjunction with the Threatened Species Recovery Hub, Rod Fensham from the University of Queensland was leader of a project to develop a national plan for Australia’s imperilled plants. From 2016 to 2020 a group of botanists including Dr Jennifer Silcock undertook field-based research filling critical knowledge gaps about poorly known and imperilled species. The report, published in 2021 states that plants comprise 70% of all species threatened in Australia. Twelve Australian plants have become extinct since colonisation, according to Jen Silcock, with another 1300 considered rare or threatened at a national level. At a state level the numbers could be ten times greater. Dr Silcock states that 90% of Australian plants are found nowhere else. Plants such as Acacia leptoneura, Banksia montana, Caladenia pumila and Pimelea venosa have fewer than five mature plants left in the wild. More than two thirds of imperilled species are long-lived trees and shrubs, eight are ground orchids, seven are perennial forbs and two are annual forbs. The good news is that with suitable management there will be no further extinctions and these plants could continue and thrive into the future.

Past land clearing has left many plants in pitifully small numbers in isolated pockets where they are susceptible to inbreeding, weed invasion, phytophthora, myrtle rust and fire. Many harmful invasive weeds are imported and spread by well-intentioned people. For example, The Farmers Handbook, 1916 edition sings the praises of Paspalum dilatatum for stock feed but it is now a widespread environmental weed and as the Handbook notes, it is very difficult to get rid of once established. It wouldn’t happen now, would it? Research by a team at Adelaide University led by Jacob Maher, using ‘web scraping’ methods, found thousands of online advertisements for illegal weed species. Maher estimates that invasive plants have cost Australia $200 billion since 1960. He calls for regulation and education to cultivate awareness among plant growers who may use these online marketplaces to advertise and or purchase these invasive species. Biosecurity agencies in Australia are now utilising the technology developed by the team to monitor and regulate the illegal trade of plants and animals.

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