Biodiversity plunges, and human action is to blame

Two new major studies examine the alarming loss of species on Planet Earth directly attributable to human action, action, and the results are, as you may expect, alarming.

And with the acceleration of global climate change, the outlook for the future looks increasingly grim.

Percentages of original species still surviving after the introduction off modern agriculture.

Percentages of original species still surviving after the advent of Homo sapiens.

The first study takes a broad look at the impacts of all human action on biodiversity.

From University College London:

Levels of global biodiversity loss may negatively impact on ecosystem function and the sustainability of human societies, according to UCL-led research.

“This is the first time we’ve quantified the effect of habitat loss on biodiversity globally in such detail and we’ve found that across most of the world biodiversity loss is no longer within the safe limit suggested by ecologists” explained lead researcher, Dr Tim Newbold from UCL and previously at UNEP-WCMC.

“We know biodiversity loss affects ecosystem function but how it does this is not entirely clear. What we do know is that in many parts of the world, we are approaching a situation where human intervention might be needed to sustain ecosystem function.”

The team found that grasslands, savannas and shrublands were most affected by biodiversity loss, followed closely by many of the world’s forests and woodlands. They say the ability of biodiversity in these areas to support key ecosystem functions such as growth of living organisms and nutrient cycling has become increasingly uncertain.

The study, published today in Science [$30 for one-day access to the article], led by researchers from UCL, the Natural History Museum and UNEP-WCMC, found that levels of biodiversity loss are so high that if left unchecked, they could undermine efforts towards long-term sustainable development.

For 58.1% of the world’s land surface, which is home to 71.4% of the global population, the level of biodiversity loss is substantial enough to question the ability of ecosystems to support human societies. The loss is due to changes in land use and puts levels of biodiversity beyond the ‘safe limit’ recently proposed by the planetary boundaries – an international framework that defines a safe operating space for humanity.

“It’s worrying that land use has already pushed biodiversity below the level proposed as a safe limit,” said Professor Andy Purvis of the Natural History Museum, London, who also worked on the study. “Decision-makers worry a lot about economic recessions, but an ecological recession could have even worse consequences – and the biodiversity damage we’ve had means we’re at risk of that happening. Until and unless we can bring biodiversity back up, we’re playing ecological roulette.”

The team used data from hundreds of scientists across the globe to analyse 2.38 million records for 39,123 species at 18,659 sites where are captured in the database of the PREDICTS project. The analyses were then applied to estimate how biodiversity in every square kilometre land has changed since before humans modified the habitat.

They found that biodiversity hotspots – those that have seen habitat loss in the past but have a lot of species only found in that area – are threatened, showing high levels of biodiversity decline. Other high biodiversity areas, such as Amazonia, which have seen no land use change have higher levels of biodiversity and more scope for proactive conservation.

“The greatest changes have happened in those places where most people live, which might affect physical and psychological wellbeing. To address this, we would have to preserve the remaining areas of natural vegetation and restore human-used lands,” added Dr Newbold.

The team hope the results will be used to inform conservation policy, nationally and internationally, and to facilitate this, have made the maps from this paper and all of the underlying data publicly available.

Animal species lost because of agricultural production

Species loss due to agricultural production.

Species loss due to agricultural production.

A second major study, this time conducted under the auspices of the European Commission: look at species loss specifically related to agricultural production.

The results are equally alarming.

From the European Commission:

In the past 500 years, over 300 vertebrate species have gone extinct, and many more are under threat of extinction — causing a lamentable decline in the variety of life on the planet. Biodiversity provides important benefits, from pollination to nutrient cycling, that are vital for human health and the economy. There is, therefore, an urgent need to address the causes of biodiversity loss.

Agriculture is a major driver of biodiversity decline. As the world’s economies are become more and more connected, international flows of crops and their products are increasing and it is important to understand the environmental effect of these changes.

There’s lots more, after the jump. . .

A recent study [open access] projected the species loss due to land-use change to date in over 800 different regions globally. To do so, the study used the ‘countryside species-area relationship’ [SAR] model. Unlike classic SAR models [which assume that areas converted for agriculture cannot host biodiversity], this model recognises that species can adapt and survive in the absence of natural habitat and, as a result, is better able to predict extinction. It is important to note that SARs provide an estimate of species ‘committed to extinction’ rather than those immediately going extinct; and the study’s results therefore represent future biodiversity losses due to habitat destruction to date. The researchers then calculated so called ‘characterisation factors’, providing species loss per square meter of cropland in each country.

This study extends that analysis by combining this measure of species loss with maps of crop yield to estimate the worldwide species extinction associated with amount of crop production. The researchers—partly funded by the European Research Council — projected species loss per tonne for 170 crops in 184 countries.

Using data on the movement of crop products between producing and consuming countries [from Food And Agriculture Organization Of The United Nations Statistics Division — FAO — databases], they also calculated the biodiversity impacts of international crop trade.

The highest impacts were observed for cropland in tropical regions, followed by temperate and then boreal regions. Impacts per tonne were multiplied by the volumes of crop production in each country to identify ‘hotspots’ of biodiversity loss.

Unsurprisingly, wheat, rice and maize — which occupy around 40% of global cropland — contributed a matching 40% to global biodiversity impacts. However, other crops, such as sugarcane, rubber, palm oil and coffee, were also responsible for high species loss, despite accounting for comparatively little global cropland. This shows that embodied land area is not the best measure of biodiversity impacts in trade flows.

There were also regional differences in impact. Populous and biodiversity-rich nations such as China, India and Brazil had the largest impacts due to domestic consumption, while exported impacts were highest in Indonesia, Thailand, India and Malaysia. Even countries with comparatively small populations such as France, Germany and Italy cause high biodiversity losses, due to their high per-capita consumption and import levels.

The highest overall impacts were due to exports from Indonesia and Mexico to the US and China, which were each estimated to cause the loss of 20 and 19 species respectively within the country of origin. The vast majority of estimated species loss [83%, or 4747 species], however, was due to agricultural land use for domestic consumption. The remainder was due to production for export [17% or 969 species]. In addition to regional extinctions, researchers also projected the number of global species extinctions due to global food consumption and trade by considering only the endemic species as an input to the SAR model.

The researchers finally ranked countries in terms of their net biodiversity impacts. Generally, industrialised countries were net importers of biodiversity impacts [i.e. they import more impacts than they export]. Imported impacts generally come from developing countries in tropical regions, which experience habitat degradation and biodiversity loss in order to produce crops for export. In Germany, for example, total German food consumption was estimated to result in the regional loss of 46 species — 43 of these were due to imported food items.

The researchers say that, although some countries are reliant on imports due to limited land and resources, others [such as France and Germany] could limit their impact on biodiversity by using more domestic resources for crop production.

Interventions in exporting countries can also help to lessen environmental impact. The researchers cite Brazil’s soy moratorium as an example, which has reduced deforestation by prompting traders, processers and retailers to stop buying beef or soy products from farms established on cleared forests.

The results could also be useful for product labelling and certification schemes. In particular, the researchers suggest that carbon footprint schemes should be extended to include biodiversity impacts.

These results could help decision makers across the globe. The researchers say it is still currently possible to take conservation measures, such as restoration of habitats, to safeguard biodiversity and reduce the projected numbers of extinctions presented in this study.


One response to “Biodiversity plunges, and human action is to blame

  1. It is children of the future that I feel sorry for. Perhaps they will never see some of th birds and animals we take for granted. Common birds like the house sparrow and moorland birds like the curlew.

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