Professor Bill Sutherland is leading a conservation revolution to reverse the dramatic loss of global biodiversity

In the wake of COVID-19, many have pointed to modern industrial farms with tightly-packed livestock as potential hothouses for further pandemics caused by "zoonotic" diseases: those transmitted from animals to humans. 

However, researchers now argue that free-range alternatives, which require far more land, would increase encroachment on natural habitats and create ever more potential for diseases carried by wild animals to come into contact with humans and jump the species barrier.         

In a paper in Royal Society Open Science, a team of scientists led by Cambridge University found a lack of sufficient evidence to conclude which way of farming is least risky, and say there is evidence that the move away from intensive farming might actually increase the risk of pandemics. They call for more research to be done before changing policies or incentivising a particular type of farming.

“High-yield or ‘intensive’ livestock farming is blamed for pandemics, but those calling for a move away from intensive farming often fail to consider the counterfactual – the pandemic risk of farming less intensively and particularly the consequences for land use,” said lead author Harriet Bartlett, a PhD candidate at Cambridge's Department of Zoology.

“Low-yield farms need far more land to produce the same amount of food compared with high-yield farms. A widespread switch to low-yield farming would result in the destruction and disturbance of vast areas of natural habitats. This increases the risk of viral spillover by disturbing wildlife that may well host the next pandemic virus and increasing contact between wildlife, people and livestock," Bartlett said.

The researchers point out that, globally, we now produce four times more meat than we did in the 1960s. Most of our meat, eggs and dairy now come from intensive farms, but such farms are thought be risky due to their crowded conditions which increase the chance of diseases ‘taking off’ and spreading rapidly.

However, intensive farms need less land than extensive, or ‘free range’, farms to produce the same amount of food – both to grow their feed and to rear their animals.

Growing demand for livestock products has caused dramatic habitat loss, say the researchers, which means we are now farming in places where livestock and people are coming into frequent contact with wildlife. They say that this contact with increasingly disturbed, stressed, and infected wildlife makes the spillover of zoonotic viruses into people or livestock more likely.

"If we were to switch from the current system to one based on extensive farming, we would need substantially more land to meet demand – resulting in the conversion of habitat roughly the size of Brazil and India between 2009 and 2050," said paper co-author Prof Andrew Balmford. "This could increase the contact between people, livestock and stressed wildlife – including wildlife that might well host the next pandemic virus."

"Intensive farms may have a greater risk of takeoff, but extensive farms may have greater risk of spillover," he said. 

The researchers say that, worryingly, we simply do not know which risk is more important for preventing future pandemics, and so it is currently impossible to determine which types of farms carry least risk overall.

Added Bartlett: "COVID-19 has demonstrated the huge potential impact of zoonotic diseases, and this study highlights that more research is urgently needed to identify how we minimise the risk of another pandemic."

Reference:

Bartlett H, Holmes MA, Petrovan SO, Williams DR, Wood JLN, Balmford A. 2022 Understanding the relative risks of zoonosis emergence under contrasting approaches to meeting livestock product demand. R. Soc. Open Sci. 9: 211573. https://doi.org/10.1098/rsos.211573

Scientists evaluate the evidence that intensive livestock farming is causing pandemics, and find that intensive farming could actually reduce the risk of future pandemics compared to 'free range' farming.

Those calling for a move away from intensive farming often fail to consider the counterfactualHarriet BartlettGetty images Portrait of young woman farmer holding fresh eggs in hands

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Global change and human actions are driving rapid changes to tidal wetlands - tidal marshes, mangroves and tidal flats - worldwide. However, ecosystem restoration and natural processes are playing a part in reducing total losses.

But efforts to estimate their current and future status at the global scale remain highly unclear due to uncertainty about how tidal wetlands respond to drivers of change.

In a new study, researchers have developed a machine-learning analysis of vast archives of historical satellite images to detect the extent, timing and type of change across the world’s tidal wetlands between 1999 and 2019.

They found that globally, 13,700 square kilometres of tidal wetlands were lost, offset by gains of 9,700 square kilometres, leading to a net loss of 4,000 square kilometres over the two-decade period.

The study is published today in the journal Science.

“We found 27 per cent of losses and gains were associated with direct human activities, such as conversion to agriculture and restoration of lost wetlands,” said Dr Nicholas Murray, Senior Lecturer and head of James Cook University’s Global Ecology Lab, who led the study.

All other changes were attributed to indirect drivers such as human impacts to river catchments, extensive development in the coastal zone, coastal subsidence, natural coastal processes and climate change.

About three-quarters of the net global tidal wetland decrease happened in Asia, with almost 70 per cent of that total concentrated in Indonesia, China and Myanmar.

“Asia is the global centre of tidal wetland loss from direct human activities. These activities had a lesser role in the losses of tidal wetlands in Europe, Africa, the Americas and Oceania, where coastal wetland dynamics were driven by indirect factors such as wetland migration, coastal modifications and catchment change,” said Murray.

The scientists found that almost three-quarters of tidal wetland loss globally has been offset by the establishment of new tidal wetlands in areas where they formerly did not occur – with notable expansion in the Ganges and Amazon deltas.

Most new areas of tidal wetlands were the result of indirect drivers, highlighting the prominent role that broad-scale coastal processes have in maintaining tidal wetland extent and facilitating natural regeneration.

“This result indicates that we need to allow for the movement and migration of coastal wetlands to account for rapid global change,” said Murray.

He added: “Global-scale monitoring is now essential if we are going to manage changes in coastal environments effectively.”

Over one billion people now live in low-elevation coastal areas globally.

Tidal wetlands are of immense importance to humanity, providing benefits such as carbon storage and sequestration, coastal protection, and fisheries enhancement.

“Protecting our coastal wetlands is critical to supporting coastal communities and the wider health of the planet. These areas are the last refuge for many plants and animals,” said Dr Thomas Worthington, Senior Research Associate in the University of Cambridge’s Department of Zoology and co-author of the study.

He added: “This data can help identify coastal areas most impacted - and therefore in need of protection, or areas where we can prioritise restoration.”

Reference:

Murray, N.J. et al: ‘High-resolution mapping of losses and gains of Earth’s tidal wetlands.’ Science, May 2022. DOI: 10.1126/science.abm9583

More information: www.globalintertidalchange.org

Adapted from a press release by James Cook University

An analysis of over a million satellite images has revealed that 4,000 square kilometres of tidal wetlands have been lost globally over twenty years.

This data can help identify coastal areas most impacted - and therefore in need of protectionThomas WorthingtonNicholas MurrayExtensive coastal development along the East Asia coastline has led to rapid declines of tidal flat ecosystems, which are the principal coastal ecosystems protecting coastal populations in China

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The specimens, collected in the late 1800s by the scientist William Caldwell, were found in the stores of Cambridge’s University Museum of Zoology.

The number of fires inside protected conservation areas across the island of Madagascar shot up dramatically when COVID-19 lockdowns led to the suspension of any on-site management for five months during 2020.

The findings suggest that governments should consider keeping some staff in protected areas at all times as an “essential service”, even during periods of health crisis and travel restriction, argue the scientists behind the study.

They say that more attention must be paid to the management of protected areas, not just expanding their coverage, at the long-delayed convention to set international biodiversity goals later this year. 

Madagascar is a renowned biodiversity “hotspot”, home to species such as its famous lemur populations that don’t exist anywhere else. The island is also a frontline in the fight between wildlife protection and habitat loss.   

The study, published today in Nature Sustainability, is the first to gauge the effects of the pandemic on protected conservation areas. 

An international team of scientists led by Cambridge and Helsinki universities used historical and contemporary fire and weather data to predict rates of burning in Madagascar’s protected areas for every month during 2012-2020.

They compared this data modelling to counts of actual blazes collected by satellites to detect periods when fires raged far beyond what might be expected from the climate and previous patterns of burning.

When the first lockdowns of 2020 halted the on-site management of protected areas, the numbers of fires – much of it in threatened forest habitat – soared by 209% in March, 223% in April, 78% in May, 248% in June and 76% in July.

However, burning quickly returned to normal levels as predicted by the modelling once management operations resumed – despite continued border closures and economic hardships as a result of the ongoing pandemic.

Researchers describe this scale of burning inside protected areas as “unprecedented” in recent Malagasy history. The only comparable periods were during two spells of civil unrest in 2013 and 2018 in the run-up to elections, but even then the fieriest month was just a 134% increase in burning.

“The disruption caused by COVID-19 clearly demonstrates the dramatic impact that interruptions to the management of protected areas can have on habitats,” said senior author Prof Andrew Balmford from the University of Cambridge.

“Over the last twenty years, excess fires in Malagasy protected areas have been limited to occasional blocks of one or two months.

“When all staff were pulled out of protected areas in March 2020 the fires spiked dramatically and continued at a ferocious level for an unprecedented five months, falling away exactly as staff started to return,” he said.      

While the team says they cannot know for sure what caused all the fires during the early months of COVID-19, lead author Dr Johanna Eklund from the University of Helsinki said that local communities already struggling economically would have come under further pressure from lockdowns.

“Madagascar has very high rates of poverty, and has a history of conflict between the livelihoods of vulnerable people and saving unique biodiversity,” said Eklund, currently a visiting researcher at Cambridge.

“The pandemic increased economic insecurity for many, so it would not be surprising if this led some to encroach on protected lands while on-site management activities were on hold.”

Eklund suggests that a lack of on-site patrolling to prevent any fires from spreading combined with communities resorting to “swidden” – or slash-and-burn – agriculture may be behind much of the spike in lockdown fires. These techniques clear vegetation for crops and cattle-grazing but are illegal inside protected areas.

“Importantly, the study did not measure fires outside conservation sites, so we cannot measure how much protected areas actually mitigated burning compared to areas without protection,” Eklund said.

The team used imaging data from NASA satellite systems capable of detecting “thermal anomalies” and noted for near real-time fire management alerts.

Eklund, who has conducted research in Madagascar for close to a decade, realised she could still remotely assist those protecting the forests. “Satellites pick up fires really well and show where protected areas are under pressure.”

Co-author Domoina Rakotobe, former coordinator for the Malagasy organisation Forum Lafa, the network of terrestrial protected area managers, added: “The high levels of burning during the lockdowns clearly shows the value of on-the-ground management, with protected area teams working with communities to support local livelihoods and safeguard natural resources.”

Scientists suggest that some staffing of protected areas should be considered “essential services” in future crises. 

When all staff were pulled out of protected areas in March 2020 the fires spiked dramaticallyAndrew BalmfordWikimedia commonsSlash and burn practise leading to fires in the region west of Manantenina, Madagascar

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Yes

How do you deal with a harmful invasive species wreaking havoc on the UK’s water pipes? You take advantage of them being fussy eaters and send them a Trojan Horse.

The size of a thumbnail, they don't have a tadpole stage and live in a 'secret world' on the forest floor

A genetic study of Zambian cuckoo finches has solved one of nature’s biggest criminal cases, an egg forgery scandal two million years in the making. Its findings suggest that the victims of this fraud may now be gaining the upper hand.

A review of 1,987 published reports of conservation interventions has found that only 8.8% reported the total cost of the intervention, and many of these were not detailed or standardised. The authors say this makes it very difficult to determine the cost-effectiveness of different interventions, and to make decisions on how to spend limited funding for biodiversity conservation.

The review, by researchers in the University of Cambridge’s Department of Zoology, is published today in the journal BioScience. This is the first time that cost reporting across a broad range of wildlife conservation interventions has been reviewed.

“If we’re serious about addressing biodiversity loss, knowing the financial costs of interventions is as important as knowing their effectiveness. But the cost of projects is rarely reported for others to benefit from,” said Thomas White, a researcher in the University of Cambridge’s Department of Zoology and first author of the paper.

Dr Silviu Petrovan, in the University of Cambridge’s Department of Zoology and a co-author of the study, added: “Wildlife conservation across the world is severely limited by funding, and the lack of information on the cost-effectiveness of different interventions makes it very difficult to prioritise where this money is spent.”

The work is part of the University of Cambridge’s Conservation Evidence project, led by Professor Bill Sutherland, which has compiled a huge resource of scientific information on the effectiveness of different conservation interventions. It is designed to support anyone making decisions about how to maintain and restore biodiversity.

For this new review, the team checked 1,987 studies in peer-reviewed journals and other reports - representing actions to conserve a range of different species and habitats - to see whether financial costs had been reported. Only 13.3% of these reported any financial costs at all.

“Even when costs are reported, the lack of consistency between reports makes it difficult for others to work out whether a cost is relevant to their project or not,” said Professor Bill Sutherland in the University of Cambridge’s Department of Zoology, a co-author of the study.

He added: “It’s frustrating because the people who implemented conservation projects probably do know how much they cost, it’s just that the information isn’t making its way into the scientific literature so others can benefit from it.”

The review found that costs were reported more often for some specific types of intervention, such as those linked with agriculture – which the authors suggest could be due to the nature of farming as an income-driven activity. Planting hedgerows or wildflower strips on farmland to encourage wildlife, or applying herbicide to control invasive plants, for example, incur costs that farmers must factor into their operations and are easily measurable.

In addition, costs were reported more often for conservation projects in Africa than in other parts of the world. The authors suggest this could be because projects in African countries are more likely to be led by conservation organisations that must prioritise cost-effectiveness.

The authors recommend that researchers, publishers and practitioners report the costs of conservation interventions in standardised formats, so that they can be used to improve decision-making by everyone planning a conservation project. They are now developing a framework to make it easier to report these costs.

“There are some easy steps to be taken to fix this - it’s just about creating a culture of reporting costs as part of reporting a conservation project, and making sure those costs are in a format that allows others to understand how much it would cost them to implement a similar action in a different context,” said White.

The authors say that in healthcare settings there is also a need to efficiently allocate resources - but unlike in conservation, healthcare decision-makers have access to a developed body of work that collates and analyses information on effects and costs. The effectiveness of conservation interventions can be more difficult to evaluate because many factors may be involved - such as acceptability to local communities, or feasibility with the skills and equipment available - as well as cost.

At COP26 in Glasgow last year, world leaders recognised the connection between the global biodiversity crisis and the climate crisis – and the critical role that nature plays in both adapting to and mitigating climate change.

“We’re losing global biodiversity at an alarming rate - it’s a real risk to society, and we need to be serious about reversing that trend. To do it will require unprecedented conservation action at a scale we aren’t yet achieving and we don’t have the finances for. So we need to be really careful about selecting the most cost-effective interventions with the money we’ve got,” said White.

This research was conducted as part of a PhD, funded by the Balfour Studentship at the University of Cambridge’s Department of Zoology.

Reference

White, T.B. et al: ‘What is the price of conservation; a review of the status quo and recommendations for improving cost reporting.’ BioScience, March 2022. DOI: 10.10.93/biosci/biac007

A new study has found that costs of conservation projects are rarely reported, making it difficult for others to make decisions on the most cost-effective interventions at a time when funding for biodiversity conservation is severely limited.

If we’re serious about addressing biodiversity loss, knowing the financial costs of interventions is as important as knowing their effectivenessThomas WhiteFrog

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Yes

Diverse native forests store more above-ground carbon, provide more water to nearby streams, and better support biodiversity and prevent soil erosion than simple tree plantations, a major new study published today in Science has found – but plantations have an advantage in wood production.

The study looked at the relative benefits of restoring native forests versus establishing a range of simple tree plantations in terms of biodiversity conservation and four key functions of value to humans - or ‘ecosystem services’ - provided by a forest: carbon storage, soil erosion control, water provisioning, and wood production.

Forest restoration is gathering pace worldwide, in part as a way to tackle climate change: deforestation is a major source of carbon emissions, and forest restoration can be a ‘nature-based climate solution’ to counter global warming. In many cases, forest restoration is also conducted for the water provisioning and flood regulation functions of forests, and as a means to prevent soil erosion and produce wood products.

“Establishing a tree plantation is useful for producing wood – but not so good for restoring biodiversity. This is a huge missed opportunity for conservation,” said Dr Fangyuan Hua, a researcher previously based in the University of Cambridge’s Department of Zoology, and first author of the paper. Hua now works at Peking University’s Institute of Ecology in China.

She added: “When the goal of a forest restoration scheme includes wood production, then there’s a trade-off to be made between environmental and production outcomes.”

Forest restoration schemes aimed at providing ecosystem services tend to involve tree plantations of just one or a small number of tree species, rather than the restoration of diverse native forests, based on an implicit assumption that tree plantations are just as effective in delivering these services. But the authors say there is no robust scientific evidence for this.

The current synthesis involved an international, cross-disciplinary team of researchers from seven countries, and it is based on an unprecedentedly large database consisting of almost 26,000 records from 264 studies conducted in 53 countries.

“This is the first time that the relative performance of different forest restoration approaches in delivering forests’ most salient services has been assessed simultaneously. We can now begin to understand the synergies and trade-offs across different restoration goals, and so help inform decision-making,” said Professor Andrew Balmford in the University of Cambridge’s Department of Zoology, senior author of the paper.

The study found that as with biodiversity, all three environment-oriented ecosystem services – aboveground carbon storage, soil erosion control, and water provisioning – are delivered better by native forests than by tree plantations. Soil erosion control in particular has the most to lose from plantation-style forest restoration, and the shortfall of plantations in water provisioning is more serious in drier climates – precisely where water is scarcer.

“When restoration goals are about environmental benefits, even if not specifically for the sake of biodiversity conservation, we should aim to restore native forests – and biodiversity will gain as a co-benefit,” said Hua.

However, for wood production, the limited evidence available showed that tree plantations can outperform native forests, highlighting a critical trade-off.

Tree plantations worldwide typically use fast-growing species like pines, firs, and Eucalyptus. These trees tend to grow tall and straight, and in actively managed plantations their growth is often enhanced by fertilisers and weeding to prevent other plants competing for nutrition and light.

In contrast, native forests contain a mix of different tree, shrub, and herbaceous species, and they tend not to be managed for growth. This provides a more suitable habitat with diverse food and other resources for a range of plants and animals to thrive, but also means that wood production may be less efficient.

“The trade-off between the environmental and production benefits a forest can provide has not been discussed much before. Restoration probably cannot meet all goals at once,” said Professor David Edwards at the University of Sheffield’s School of Biosciences and another senior author of the study.

In addition to a need to weigh competing goals, this finding also means that plantations might indirectly provide environmental benefits, by allowing other, higher-biodiversity forests to be ‘spared’ from being cut down for wood production.

“Plantations need to be integrated into a coherent land-use plan, so that their better performance at producing wood gets translated into improved conservation of environmentally valuable forests elsewhere,” Balmford added.

The study also found that for many old or abandoned plantations across the world that seem no longer used for wood production, their environmental performance falls short of native forests. Given that these plantations seem to be common, there are probably significant environmental benefits to be gained from restoring them to native forests.

The United Nations (UN) have declared 2021-2030 the ‘UN Decade on Ecosystem Restoration’. Along with many other climate-related initiatives, this promotes the scaling-up of restoration efforts on a global scale to breathe new life into our degraded ecosystems, including the restoration of forests on millions of hectares of deforested and degraded land across the world. Such restoration efforts have the potential to generate immense environmental and social benefits – but only if they are guided by a robust understanding of their consequences for environmental and other outcomes.

This research was funded by the Newton Fund of the Royal Society (UK) and the São Paulo Research Foundation (Brazil).

Reference

Hua, F. et al: ‘The biodiversity and ecosystem service contributions and trade-offs of forest restoration approaches.’ Science, March 2022. DOI: 10.1126/science.abl4649

Co-authors of this study are based at 11 institutions in seven countries: University of Cambridge, Peking University, King’s College London, Yunnan University, University of São Paulo, Universidad de La Frontera, the Netherlands Organisation for Applied Scientific Research, University of New South Wales, the Commonwealth Scientific and Industrial Research Organisation, University of Aberdeen, and University of Sheffield.

Forest restoration schemes should prioritise restoring native forests for greatest climate and environmental benefits, but these benefits incur a trade-off with wood production in comparison with tree plantations.

When restoration goals are about environmental benefits, even if not specifically for the sake of biodiversity conservation, we should aim to restore native forests – and biodiversity will gain as a co-benefitFangyuan Huatibor13, iStock/Getty ImagesPlanting a young tree

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YesLicense type: Attribution

New study uses data on lead levels in the livers of thousands of dead raptors to calculate the impact of lead poisoning on population size.