Nav: Home

Introduced species overlooked in biodiversity reporting

April 27, 2018

Nature is intimately connected with human well-being of current and future generations - which is why an array of reports track the state of biodiversity and predict the impact of our way of life on its evolution. These reports are based on several indicators that only take indigenous - i.e. "original" - species into account for each region. Yet today modern environments are made up of indigenous and introduced species. The introductions are either deliberate - as is the case, for example, with agricultural crops - or accidental, as was the case with the Asian hornet or the box tree moth. Although these introduced species play important roles, they are ignored by specialists, a fact that partly distorts the international nature reports. The study by the University of Geneva (UNIGE), published in the journal PLOS Biology, recommends that the positive and negative contributions made by these species should be included so that the public has an accurate view over the surrounding nature and its evolution.

Biodiversity protection at present is intimately linked to protecting the indigenous species and environments that are specific to each region worldwide, the aim being to safeguard the "authenticity" of landscapes and their ecosystems. The indicators used by biologists are based exclusively on species of origin; in other words, they overlook the presence of introduced species. These indicators inform international reports on biodiversity, introducing a bias at the source, argues Martin Schlaepfer, a researcher at UNIGE's Institute of Environmental Sciences (ISE). In short, a section of nature is deliberately ignored. Why?

Fear of the invader

Biologists generally favour the protection of native species. By contrast, introduced species are viewed as undesirable by the conservation community because a subset can generate undesirable effects. "But around 88% of species introduced to Europe are not problematic," explains Schlaepfer. "And among those that do create a problem, we generally only look at their flaws, without factoring in the positive features they can also generate." For example, the giant goldenrod (Solidago gigantea) is a species of plant introduced from North America. It is considered invasive in Switzerland because it can dominate environments bordering agricultural land. However, in addition to boasting medicinal properties, the giant goldenrod also facilitates favourable biological interactions with pollinators. In a similar manner, American crayfish - which are invasive in European lakes - provide the catering industry with an important source of food.

Reports that are relevant for politicians and the public

By deliberately omitting introduced species, biodiversity reports do not accurately reflect nature as it really is. "If you focus on trees in the Canton of Geneva, there are 88 indigenous species. But there are 597 introduced tree species in the canton!" points out Schlaepfer. A large part of the natural world surrounding the people of Switzerland is knowingly excluded from the indexes. "If we want to remain relevant for political institutions, we now need to consider nature in its entirety," insists the UNIGE biologist. But what would the impact be on the results of the reports?

Planetary boundaries

In 2012, the High-Level Group on Global Sustainability produced a UN-validated report that identified 12 indicators for measuring planetary boundaries, i.e. the limits that humankind must not exceed in order to enable life to continue on Earth. One of these indicators is biodiversity. Biologists observe the average abundance of species originally present in a region; if the average abundance drops by more than 10%, experts consider that nature has been altered too extensively and that the health of future generations is in danger.

"But these reports do not include the potentially useful functions brought about by species that were not originally present, even though they are constantly interacting with the indigenous biodiversity," says Schlaepfer. "If they included these factors, then the percentage of the land area deemed to be in poor condition would decrease from 58% to 48%, reducing the severity of humankind's impact on nature."

Looking at all of nature's species in order to follow their evolution

In his study, Schlaepfer challenges the indicators used in international reports on biodiversity. "Understanding nature and its links to human well-being means assessing every species at its fair value, because they all interact with humans and form part of the reality of the evolution of biodiversity", points out Schlaepfer. Furthermore, introduced species may also be in the majority, mainly in urban areas. "Trees that are culturally important for the public are often introduced species, and they illustrate why we must include the positive aspects of these species that contribute to the well-being of humans, even if they contradict the values of some biologists."
-end-


Université de Genève

Related Biodiversity Articles:

Biodiversity is 3-D
The species-area relationship (SAC) is a long-time considered pattern in ecology and is discussed in most of academic Ecology books.
Thought Antarctica's biodiversity was doing well? Think again
Antarctica and the Southern Ocean are not in better environmental shape than the rest of the world.
Antarctica's biodiversity is under threat
A unique international study has debunked the popular view that Antarctica and the Southern Ocean are in much better ecological shape than the rest of the world.
Poor outlook for biodiversity in Antarctica
The popular view that Antarctica and the Southern Ocean are in a much better environmental shape than the rest of the world has been brought into question in a study publishing on March 28 in the open access journal PLOS Biology, by an international team lead by Steven L.
Temperature drives biodiversity
Why is the diversity of animals and plants so unevenly distributed on our planet?
Biodiversity needs citizen scientists
Could birdwatching or monitoring tree blossoms in your community make a difference in global environmental research?
Biodiversity loss in forests will be pricey
A new global assessment of forests -- perhaps the largest terrestrial repositories of biodiversity -- suggests that, on average, a 10 percent loss in biodiversity leads to a 2 to 3 percent loss in the productivity, including biomass, that forests can offer.
Biodiversity falls below 'safe levels' globally
Levels of global biodiversity loss may negatively impact on ecosystem function and the sustainability of human societies, according to UCL-led research.
Unravelling the costs of rubber agriculture on biodiversity
A striking decline in ant biodiversity found on land converted to a rubber plantation in China.
Nitrogen is a neglected threat to biodiversity
Nitrogen pollution is a recognized threat to sensitive species and ecosystems.

Related Biodiversity Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#530 Why Aren't We Dead Yet?
We only notice our immune systems when they aren't working properly, or when they're under attack. How does our immune system understand what bits of us are us, and what bits are invading germs and viruses? How different are human immune systems from the immune systems of other creatures? And is the immune system so often the target of sketchy medical advice? Those questions and more, this week in our conversation with author Idan Ben-Barak about his book "Why Aren't We Dead Yet?: The Survivor’s Guide to the Immune System".