.

  • Written by Jaco Le Roux, Associate Professor, Macquarie University
Plant extinctions have skyrocketed, driven in large part by land clearing and climate change. Graphic Node/Unsplash, CC BY-SA

Earth is seeing an unprecedented loss of species, which some ecologists are calling a sixth mass extinction. In May, a United Nations report warned that 1 million species are threatened by extinction. More recently, 571 plant species were declared extinct.

But extinctions have occurred for as long as life has existed on Earth. The important question is, has the rate of extinction increased? Our research, published today in Current Biology, found some plants have been going extinct up to 350 times faster than the historical average – with devastating consequences for unique species.


Read more: Earth's sixth mass extinction has begun, new study confirms


Measuring the rate of extinction

“How many species are going extinct” is not an easy question to answer. To start, accurate data on contemporary extinctions are lacking from most parts of the world. And species are not evenly distributed – for example, Madagascar is home to around 12,000 plant species, of which 80% are endemic (found nowhere else). England, meanwhile, is home to only 1,859 species, of which 75 (just 4%) are endemic.

Areas like Madagascar, which have exceptional rates of biodiversity at severe risk from human destruction, are called “hotspots”. Based purely on numbers, biodiversity hotspots are expected to lose more species to extinction than coldspots such as England.

But that doesn’t mean coldspots aren’t worth conserving – they tend to contain completely unique plants.

We are part of an international team that recently examined 291 modern plant extinctions between biodiversity hot- and coldspots. We looked at the underlying causes of extinction, when they happened, and how unique the species were. Armed with this information, we asked how extinctions differ between biodiversity hot- and coldspots.

Unsurprisingly, we found hotspots to lose more species, faster, than coldspots. Agriculture and urbanisation were important drivers of plant extinctions in both hot- and coldspots, confirming the general belief that habitat destruction is the primary cause of most extinctions. Overall, herbaceous perennials such as grasses are particularly vulnerable to extinction.

However, coldspots stand to lose more uniqueness than hotspots. For example, seven coldspot extinctions led to the disappearance of seven genera, and in one instance, even a whole plant family. So clearly, coldspots also represent important reservoirs of unique biodiversity that need conservation.

We also show that recent extinction rates, at their peak, were 350 times higher than historical background extinction rates. Scientists have previously speculated that modern plant extinctions will surpass background rates by several thousand times over the next 80 years.

So why are our estimates of plant extinction so low?

First, a lack of comprehensive data restricts inferences that can be made about modern extinctions. Second, plants are unique in – some of them live for an extraordinarily long time, and many can persist in low densities due to unique adaptations, such as being able to reproduce in the absence of partners.

Let’s consider a hypothetical situation where we only have five living individuals of Grandidier’s baobab (Adansonia grandidieri) left in the wild. These iconic trees of Madagascar are one of only nine living species of their genus and can live for hundreds of years. Therefore, a few individual trees may be able to “hang in there” (a situation commonly referred to as “extinction debt”) but will inevitably become extinct in the future.

Finally, declaring a plant extinct is challenging, simply because they’re often very difficult to spot, and we can’t be sure we’ve found the last living individuals. Indeed, a recent report found 431 plant species previously thought to be extinct have been rediscovered. So, real plant extinction rates and future extinctions are likely to far exceed current estimates.

There is no doubt that biodiversity loss, together with climate change, are some of the biggest challenges faced by humanity. Along with human-driven habitat destruction, the effects of climate change are expected to be particularly severe on plant biodiversity. Current estimates of plant extinctions are, without a doubt, gross underestimates.


Read more: Despite thoughts of death, atheists’ convictions grow stronger


However, the signs are crystal clear. If we were to condense the Earth’s 4.5-billion-year-old history into one calendar year, then life evolved somewhere in June, dinosaurs appeared somewhere around Christmas, and the Anthropocene starts within the last millisecond of New Year’s Eve. Modern plant extinction rates that exceed historical rates by hundreds of times over such a brief period will spell disaster for our planet’s future.

Jaco Le Roux receives funding from the South African National Research Foundation.

Florencia Yanelli receives funding from the Working for Water Programme (SA) and the Centre for Invasion Biology, Stellenbosch University (SA).

Heidi Hirsch receives funding from the Centre for Invasion Biology, Stellenbosch University.

Maria Loreto Castillo receives funding from the Centre for Invasion Biology, Stellenbosch University.

José María Iriondo Alegría and Marcel Rejmánek do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.

Authors: Jaco Le Roux, Associate Professor, Macquarie University

Read more http://theconversation.com/plants-are-going-extinct-up-to-350-times-faster-than-the-historical-norm-122255

Primary Questions to Ask Yourself Before Choosing an Office Space in Philadelphia

Choosing your first office space is thrilling. The excitement of finally setting up your own office is so satisfying. When you start scouting around to select your office space, there are so many fa...

Sarah Williams - avatar Sarah Williams

Freedom And Flexibility - How A Virtual Office Allows For Greater Adaptability

Being able to adapt to changing circumstances and economic conditions is essential in business. For entrepreneurs and startups who want to maximise their chances of success regardless of outside cir...

News Company - avatar News Company

Eat your heart out: native water rats have worked out how to safely eat cane toads

Water rats in Western Australia are safely hunting cane toads. Author providedAustralia’s water rats, or Rakali, are one of Australia’s beautiful but lesser-known native rodents. And these...

Marissa Parrott, Reproductive Biologist, Wildlife Conservation & Science, Zoos Victoria, and Honorary Research Associate, BioSciences, University of Melbourne - avatar Marissa Parrott, Reproductive Biologist, Wildlife Conservation & Science, Zoos Victoria, and Honorary Research Associate, BioSciences, University of Melbourne

Curious Kids: where do phobias come from?

Phobias are an intense fear of very specific things like objects, places, situations or animals. ShutterstockIf you have a question you’d like an expert to answer, send it to curiouskids@theconv...

Lara Farrell, Associate Professor and Clinical Psychologist, Griffith University - avatar Lara Farrell, Associate Professor and Clinical Psychologist, Griffith University

Best Family-Friendly Zoos In America

Zoos have always been part of family travel destinations. This is where your kids get to see the animals that they only often see on their books. Visiting one also provides a learning experience for...

News Company - avatar News Company

Activists are using the climate emergency as a new legal defence to justify law-breaking

The phrase “climate emergency” became part of the political lexicon this year. Governments at all levels made declarations of a climate emergency, as did various organisations such as the ...

Nicole Rogers, Senior lecturer, School of Law and Justice, Southern Cross University - avatar Nicole Rogers, Senior lecturer, School of Law and Justice, Southern Cross University

Don't tear it down: the idea behind Labor's National Rental Affordability Scheme is worth saving

The Grattan Institute has condemned the National Rental Affordability Scheme as a $1 billion windfall to developers. www.shutterstock.comLabor’s Rudd-era National Rental Affordability Scheme (NR...

Marcus Luigi Spiller, Associate Professor (Urban Planning) - honorary  , University of Melbourne - avatar Marcus Luigi Spiller, Associate Professor (Urban Planning) - honorary , University of Melbourne

City share-house rents eat up most of Newstart, leaving less than $100 a week to live on

Even when sharing a house, the average cost of rent means very little is left over from the Newstart allowance for food and living costs. shutterstock.comIn all Australia’s capital cities, avera...

Simone Casey, Research Associate, Future Social Service Institute, RMIT University - avatar Simone Casey, Research Associate, Future Social Service Institute, RMIT University

Users (and their bias) are key to fighting fake news on Facebook – AI isn't smart enough yet

On its own, human judgement can be subjective and skewed towards personal biases. The information we encounter online everyday can be misleading, incomplete or fabricated. Being exposed to “fa...

Gianluca Demartini, Associate professor, The University of Queensland - avatar Gianluca Demartini, Associate professor, The University of Queensland

Fairest and best? Status counts in the Brownlow Medal

Tonight is the AFL’s annual night of nights, the red-carpet spectacular known as the Brownlow Medal vote count. The Brownlow is awarded to the season’s “fairest and best” play...

Liam Lenten, Senior Lecturer, Department of Economics and Finance, La Trobe University - avatar Liam Lenten, Senior Lecturer, Department of Economics and Finance, La Trobe University

How Australians talk about tucker is a story that'll make you want to eat the bum out of an elephant

Wes Mountain/The Conversation, CC BY-NDNot to put a damper on things, but Australian food hasn’t always made us happy little Vegemites. One needn’t look further than the humble meat pie ...

Howard Manns, Lecturer in Linguistics, Monash University - avatar Howard Manns, Lecturer in Linguistics, Monash University

In a chatty world, losing your speech can be alienating. But there's help

People who have trouble with their speech, say after a stroke, can find it challenging. But a speech pathologist can help. from www.shutterstock.comSam is a high school drama teacher — articulat...

Kirrie J Ballard, Professor, Speech Pathology, University of Sydney - avatar Kirrie J Ballard, Professor, Speech Pathology, University of Sydney

From crime fighters to crime writers - a new batch of female authors brings stories that are closer to home

In Dervla McTiernan’s book, The Scholar, published earlier this year, women are consistently used as the “fall guys” for men with high aspirations. Two young women are killed when th...

Lili Pâquet, Lecturer in Writing, University of New England - avatar Lili Pâquet, Lecturer in Writing, University of New England

10 ways to get the most out of silent reading in schools

Children need time and space to enjoy the books they choose to read in schools. Shutterstock/wavebreakmediaReading aloud can help young children learn about new words and how to sound them. There&rsqu...

Margaret Kristin Merga, Senior Lecturer in Education, Edith Cowan University - avatar Margaret Kristin Merga, Senior Lecturer in Education, Edith Cowan University

'Edible forests' can fight land clearing and world hunger at the same time

A Nepalese woman collects mushroom in a forest. Jagannath Adhikari, Author providedReducing emissions from deforestation and farming is an urgent global priority if we want to control climate change. ...

Jagannath Adhikari, Sessional Lecturer, UNSW - avatar Jagannath Adhikari, Sessional Lecturer, UNSW

Comic explainer: young disabled New Zealanders on the barriers to a better life

Our research project explored the everyday lives of disabled young people, aged from 12 to 25 years, with mobility, vision and hearing impairments. We measured and asked them about factors that enable...

Penelope Carroll, Researcher in Public Health, Massey University - avatar Penelope Carroll, Researcher in Public Health, Massey University

View from The Hill: To go to China you have to be invited: Morrison

Scott Morrison was frank, when quizzed at a news conference during his visit to Washington, on whether he would be seeking to travel to China in the next year. “Well, you have to be invited to ...

Michelle Grattan, Professorial Fellow, University of Canberra - avatar Michelle Grattan, Professorial Fellow, University of Canberra

VIDEO: Michelle Grattan on the family law inquiry - and the UN climate change summit

University of Canberra Deputy Vice-Chancellor Leigh Sullivan discusses Scott Morrison’s new family law inquiry with Michelle Grattan. They also speak of the developments in the Tamil family from...

Michelle Grattan, Professorial Fellow, University of Canberra - avatar Michelle Grattan, Professorial Fellow, University of Canberra

Climate explained: why don't we have electric aircraft?

CC BY-ND Climate Explained is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change. If yo...

Dries Verstraete, Senior Lecturer in Aerospace Design and Propulsion, University of Sydney - avatar Dries Verstraete, Senior Lecturer in Aerospace Design and Propulsion, University of Sydney

Sick and Tired of Your Dead End Job? Try Teaching!

Tired of the same old grind at the office? Want an opportunity to impact lives both in your community and around the world? Do you love to travel and have new experiences? Teaching English is the perfect job for you! All you need is a willingness to ...

News Company - avatar News Company

The Impact of an Aging Population in Australia

There’s an issue on the horizon that Australia needs to prepare for. The portion of elderly citizens that make up the country’s overall population is increasing, and we might not have the infrastructure in place to support this. Australians h...

News Company - avatar News Company

LifeStyle

Yvonne Allen: Eight ways to super impress someone on a first date

According to Yvonne Allen well known relationship mentor, psychologist and matchmaker, a first dat...

Picking The Right Crystal Yoni Egg: Tips And Instructions

When you are ready to pick your own crystal yoni egg, you need to decide what you will use it for...

Top 5 Tips for Paddleboarding In Whitewater

Paddleboarding can be relaxing as well as intense. If you occasionally want to do something differen...

3 Most Promising Career Occupations for Graduates in 2019

Studying in college is a great adventure which opens up lots of career opportunities. Yet, at times...