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The Challenge of Monitoring Biodiversity

By Claire Asher, on 4 August 2015

a guest blog by Charlie Outhwaite, written for the 2015 Write About Research Competition.

Biological diversity, or biodiversity, is a complex term encompassing the variety of life found on Earth. It incorporates not only differences between species but within species themselves and of the environments and ecosystems where they are found. We as humans benefit a great deal from the biodiversity on Earth in a range of ways; from the clean air we breathe to food, materials and medicines that are produced as a result. These products or services are known as ecosystem services and these services depend on biodiversity. Monitoring the status of biodiversity is therefore an important area of research, but offers its own challenges. New methods offer the chance to utilise data that has been underused in the past due to its associated biases and we are now able to explore and monitor the responses of biodiversity over time for many more species than has previously been possible. This has opened the door not only to more knowledge on a greater range of species but also allows us to look into what aspects are influencing these changes, such as the impact of climate change.

In April 1992, an agreement was signed by a number of government parties to the Convention on Biological Diversity (CBD) agreeing to the global target “to achieve by 2010 a significant reduction of the current rate of biodiversity loss”. Unfortunately, this target was never achieved and so, in 2010 an updated plan was established at the tenth meeting of the Convention in Nagoya, Japan. This revised plan includes 20 main targets, known as the Aichi Biodiversity targets, under 5 strategic goals each encompassing one aspect to benefit biodiversity.

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In order to measure progress towards these targets, at both a national and a global scale, a number of indicators of change have been developed, these are often simple graphs showing increases or decreases in the variable being monitored. For the UK, these are published annually by DEFRA (the Department for Environment, Food and Rural Affairs) in the Biodiversity Indicators in your Pocket report (BIYP). Indicators are composite measures of change and are a simple and easy way to communicate change over time. The most recent BIYP report includes a suite of indicators aimed to report on UK progress towards the Aichi targets. These range from indicators of change in volunteer time spent in conservation organisations to assess progress towards strategic goal A (Address the underlying causes of biodiversity loss by mainstreaming biodiversity across government and society) to indicators of the status of UK priority species for Strategic Goal C (To improve the status of biodiversity by safeguarding ecosystems, species and genetic diversity).

However, the monitoring of aspects of the goals is not simple and biodiversity itself provides a great challenge. Take target 12 for example; “By 2020 the extinction of known threatened species has been prevented and their conservation status, particularly of those most in decline, has been improved and sustained”. In order to assess whether the decline and extinction of threatened species has been prevented we need to be able to measure how many there are in the first place, and how that changes over time. Ideally, we would like to go out and count exactly how many there are of each species, but of course this is not possible. It would be difficult enough going out and counting every species in your own garden, let alone across the whole country. So, we have to use the next best alternative. In some cases, standardised monitoring schemes such as the Breeding Bird Survey are set up and species numbers are monitored using standardised techniques across specific sites. This data can then be used to accurately estimate the abundance of those species observed. However, this kind of data is costly to collect and requires a lot of time and effort and so, is not available for the majority of species.

An alternative form of data is biological records. Biological records are a data type that is high in quantity but has a number problems associated with it. Often collected by volunteers through citizen science projects, this type of data can be highly variable in its level of accuracy and completeness. However, with interest and participation in citizen science increasing, the amount of biological records data available is rising. With so much data on hand, and often for those groups of species that are less well studied (such as insects) and for which monitoring scheme data is unavailable, it is important that these data are put to good use. However, because of the problems associated with this data type, it is underused and underappreciated. The main problem is that it is collected in an unstandardized way, which introduces bias into the data. Records will often be collected by an individual at a location of their choosing and they may not report every species they see.

A number of robust statistical methods have been developed that are able to account for these associated biases. Bayesian occupancy models are a complex statistical technique which has been shown by Isaac et al (2015) to most effectively account for the biases of this type of data and produce reliable indicators of change. It is now being used to monitor changes in the biodiversity of less well studied groups of species using biological records from various recording schemes. For these species groups, this kind of data is all that is available and so employing these new methods for analysing biological records is enabling greater research into areas where little is currently known.

However, with human induced drivers being the biggest threat to biodiversity loss, it is not enough to simply monitor changes in species trends. There is a growing need to understand what is causing these trends and how a species’ traits can increase its susceptibility towards these drivers. Through a more thorough understanding of the effects drivers such as climate change have on a group of species, and which species within that group will be most affected, it would be possible to design conservation interventions to target those species most at risk, preventing future declines. This process could act as a form of triage, in determining those species that will be most affected so that conservation and policy action can be targeted to those areas in the first instance. This is becoming increasingly urgent as a mid-term report on progress towards meeting the CBD 2020 targets by Tittensor et al indicates that progress is not positive.

References

  • Defra (2014) UK Biodiversity Indicators 2014: Measuring progress towards halting biodiversity loss. Retrieved from http://jncc.defra.gov.uk/page-4229
  • Isaac, N. J. B., van Strien, A. J., August, T. A., de Zeeuw, M. P., & Roy, D. B. (2014). Statistics for citizen science: extracting signals of change from noisy ecological data. Methods in Ecology and Evolution, doi:10.1111/2041-210X.12254
  • Tittensor, D. P., Walpole, M., Hill, S. L. L., Boyce, D. G., Britten, G. L., Burgess, N. D., … Parks, B. C. (2014). A mid-term analysis of progress toward international biodiversity targets, (October), 1–8.

CharlieOuthwaiteCharlie is a first year PhD Student based at the Centre for Ecology and Hydrology, Wallingford and working within the Biological Records Centre. Charlie’s PhD is linked with CBER UCL and the RSPB through a CASE partnership. Her research is looking into biodiversity status, drivers and indicators from biological records. Charlie’s interest in measuring and reporting changes in biodiversity has grown since working as an intern and research assistant within the Indicators and Assessments Unit at the Institute of Zoology. Within these roles she worked on the Living Planet Index and on developing a Canadian biodiversity indicator. Going from the reporting and development side of indicators she now hopes to reveal the role of drivers of change and how these interact with species traits to affect changes in biodiversity.

PREDICTS Project: Global Analysis Reveals Massive Biodiversity Losses

By Claire Asher, on 21 May 2015

The changing climate is only one of a myriad of pressures faced by global biodiversity – we are also changing habitats and altering land-use on an unprecedented scale. The first global analysis published from the PREDICTS project reveals the striking global effect of land-use change on local biodiversity patterns, and highlights the importance of future climate-mitigation strategies in shaping the future of biodiversity and the vital ecosystem services it provides.

Human activities are causing widespread change to and degradation of habitats, which has been linked to serious biodiversity declines globally. Land-use change comes in many forms, from deforestation and agriculture to urban development and road-building, and previous work by the PREDICTS project has shown how different types of land-use influence different types of species differently. We are interested in biodiversity loss at a global scale, and many metrics aim to quantify this, but viewing global patterns can obscure local-scale changes that are likely to be more important for the resilience of ecosystem services. Ecosystem services include clean air and water, food, medicine and nutrient cycling, among others, and are vital both for biodiversity and for human survival and well-being. The PREDICTS project considers local-scale changes to biodiversity in response to land-use change, to produce a powerful model that can be used to project the impact of future land-use and climate change. In their latest paper, published in Nature last month, the PREDICTS team reveal their most comprehensive analysis to date, showing massive reductions in local biodiversity since 1500, and projecting further widespread losses under several future climate and land-use scenarios. There is still hope, however, and strategies to mitigate greenhouse gas emissions without major land-use change could offer the opportunity for global biodiversity to recover.

Understanding the Past and Present

The PREDICTS team have assembled a database of over 1,130,000 records of species abundance and nearly 330,000 records of species richness across more than 11,000 sites worldwide. The database includes results from 284 scientific publications, and represents over 25,000 species. Using this incredible resource, the team compared species richness and abundance between sites with different land-use types and produced a statistical model to quantify local biodiversity responses to land-use change. This enabled them to infer changes in species assemblages since the year 1500.They found that species richness and total abundance were both strongly influenced by land-use type and intensity, with reductions in biodiversity outside of primary vegetation and the worst losses seen in intensively used areas. Local biodiversity was also negatively impacted by human population density and accessibility (measured by the distance to the nearest main road). In the worst-affected habitats, changing land-use away from primary vegetation reduced species richness and abundance by an average of about 40%, and globally, land-use change was responsible for an average reduction in species richness and abundance of around 9%. The value of secondary vegetation (forest recovering from past damage) for biodiversity depended strongly on how mature the habitat was, with species diversity increasing over time, and mature secondary vegetation most closely resembling primary habitats. Restoration projects do, therefore, have the power to return biodiversity to damaged habitats, but (unsurprisingly!) it will take time.

Previous estimates have suggested that local losses of species richness and diversity greater than 20% are likely to substantially impair ecosystem services contributed to by biodiversity and reduce overall ecosystem function. Some scientists believe biodiversity loses at this scale may push populations towards ‘tipping points’ where ecosystem function declines lead to further species loss. Thus, in the worst-affected habitats considered by the PREDICTS team, which experienced on average a 31% loss of local species richness, ecosystem function is likely to be substantially impaired.

Changes in species richness and abundance may underestimate the real impact of land-use change because the measure fails to capture the composition of a community. The team therefore compared the species composition between sites and found that communities tended to be similar under similar land-use. Communities living in primary and secondary vegetation were most alike, while more disturbed habitats such as plantation forest, pasture and cropland tended to support a different cluster of more human-tolerant species. Human-dominated landscapes lost far more natural local diversity than more pristine sites where natural vegetation remains.

Reconstructing past biodiversity loss indicated that the greatest reductions in species richness occurred in (unsurprisingly) the 19th and 20th centuries, and that by 2005 local species richness worldwide had reduced by 13.6% due to land-use change and related anthropogenic pressures. How will this trend continue into the future?

Projecting the Future

The PREDICTS team then went on to combine their analysis of current species’ responses to land-use change with four climate scenarios produced by the Intergovernmental Panel on Climate Change, to project future changes in biodiversity under different socioeconomic scenarios of land-use change. Projecting as far as 2095, the PREDICTS model projects rapid biodiversity losses under a ‘business-as-usual’ land-use scenario, with species richness projected to drop a further 3.5%. These loses are not likely to be uniformly distributed, however, with the largest loses predicted to occur in economically poor but highly biodiverse regions, such as Southeast Asia and Sub-Saharan Africa. Buisness-as-usual results in rapid human population growth and agricultural expansion, and most closely matches recent trends, and yields the most severe losses in biodiversity of any scenario considered by the PREDICTS team. Continuing on as we have been does not bode well for biodiversity or the vital ecosystem services it provides us.

Projected net change in local richness from 1500 to 2095. Source: http://www.nature.com/nature/journal/v520/n7545/abs/nature14324.html.

Projected net change in local richness from 1500 to 2095. Source: http://www.nature.com/nature/journal/v520/n7545/abs/nature14324.html.

Perhaps surprisingly, the second-worst scenario for biodiversity is in fact the scenario with the least climate change (IMAGE2.6). This is because this scenario achieved reduced emmisions and climatic change by rapidly converting the world’s forests (primary vegetation) to crops and biofuel. In contrast, the IPCC scenario MiniCAM 4.5, which mitigates climate change through the use of carbon markets, crop improvements and diet shifts, however, is projected to increase average species richness. Not all our possible solutions to curb greenhouse gas emissions and reduce climate change will necessarily spell good news for biodiversity.

It isn’t all bad news, though. The right strategies can promote biodiversity globally, even producing increases in species richness by 2095 of up to 2%, and the PREDICTS team say widespread biodiversity loss is not inevitable. Concerted efforts and the right socioeconomic choices can make long-term global sustainability of biodiversity an achievable goal.

Original Article:

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This research was made possible by funding from the Natural Environment Research Councik (NERC) and the Biotechnology and Biological Sciences Research Council (BBSRC).

Changing Perspectives in Conservation

By Claire Asher, on 18 December 2014

Our views of the importance of nature and our place within have changed dramatically over the the last century, and the prevailing paradigm has profound influences on conservation from the science that is conducted to the policies that are enacted. In a recent perspectives piece for Science, GEE’s Professor Georgina Mace considered the impacts that these perspectives have on conservation practise.

Before the late 1960s, conservation thinking was largely focussed on the idea that nature is best left to its own devices. This ‘nature for itself‘ framework centred around the value of wilderness and unaltered natural reserves. This viewpoint stemmed from ecological theory and research, however by the 1970s it became apparent that human activities were having severe and worsening impacts on species, and that this framework simply wasn’t enough. This led to a shift in focus towards the threats posed to species by human activities and how to reduce these impacts, a ‘nature despite people‘ approach to conservation. This is the paradigm of protected areas and quotas, designed to reduce threats posed and ensure long-term sustainability.

Changing views of nature and conservation, Mace (2014)

Changing views of nature and conservation, Mace (2014)

By the 1990s, people had begun to appreciate the many and varied roles that healthy ecosystems play in human-wellbeing; ecosystem services are crucial to providing clean water, air, food, minerals and raw materials that sustain human activities. Shifting towards a more holistic, whole-ecosystem viewpoint which attempted to place economic valuations on the services nature provides, conservation thinking entered a ‘nature for people‘ perspective. Within this framework, conservationists began to consider new metrics, such as the minimum viable population size of species and ecosystems, and became concerned with ensuring sustainable harvesting and exploitation. In the last few years, this view has again shifted slightly, this time to a ‘people and nature‘ perspective that values long-term harmonious and sustainable relationships between humans and nature, and which includes more abstract benefits to humans.

Changing conservation paradigms can have a major impact on how we design conservation interventions and what metrics we monitor to assess their success. Standard metrics of conservation, such as the IUCN classification systems, can be easily applied to both a ‘nature for itself’ and a ‘nature despite people’ framework. In contrast, a more economic approach to conservation requires valuations of ecosystems and the services they provide, which is far more complex to measure and calculate. Even more difficult is measuring the non-economic benefits to human well-being that are provided for by nature. The recent focus on these abstract benefits may make the success of conservation interventions more difficult to assess under this framework.

The scientific tools, theory and techniques available to conservation scientists have not always kept up with changing conservation ideologies, and differing perspectives can lead to friction between scientists and policy-makers alike. In the long-term a viewpoint that recognises all of these viewpoints may be the most effective in directing and appraising conservation management. Certainly, greater stability in the way in which we view our place in nature would afford science the opportunity to catch-up and develop effective and empirical metrics that can be meaningfully applied to conservation.

Original Article:

() Science

Life Aquatic:
Diversity and Endemism in Freshwater Ecosystems

By Claire Asher, on 6 November 2014

Freshwater ecosystems are ecologically important, providing a home to hundreds of thousands of species and offering us vital ecosystem servies. However, many freshwater species are currently threatened by habitat loss, pollution, disease and invasive species. Recent research from GEE indicates that freshwater species are at greater risk of extinction than terrestrial species. Using data on over 7000 freshwater species across the world, GEE researchers also show a lack of correlation between patterns of species richness across different freshwater groups, suggesting that biodiversity metrics must be carefully selected to inform conservation priorities.

Freshwater ecosystems are of great conservation importance, estimated to provide habitat for over 125,000 species of plant and animal, as well as crucial ecosystem services such as flood protection, food, water filtration and carbon sequestration. However, many freshwater species are threatened and in decline. Freshwater ecosystems are highly connected, meaning that habitat fragmentation can have serious implications for species, while pressures such as pollution, invasive species and disease can be easily transmitted between different freshwater habitats. Recent work by GEE academics Dr Ben Collen, in collaboration with academics from the Institute of Zoology, investigated the global patterns of freshwater diversity and endemism using a new global-level dataset including over 7000 freshwater mammals, amphibians, reptiles, fishes, crabs and crayfish. Many freshwater species occupy quite small ranges and the authors were also interested in the extent to which species richness and the distribution threatened species correlated between taxonomic groups and geographical areas.


The study showed that almost a third of all freshwater species considered are threatened with extinction, with remarkably little large-scale geographical variation in threats. Freshwater diversity is highest in the Amazon basin, largely driven by extremely high diversity of amphibians in this region. Other important regions for freshwater biodiversity include the south-eastern USA, West Africa, the Ganges and Mekong basins, and areas of Malaysia and Indonesia. However, there was no consistent geographical pattern of species richness in freshwater ecosystems.

Freshwater species in certain habitats are more at risk than others – 34% of species living in rivers and streams are under threat, compared to just 20% of marsh and lake species. It appears that flowing freshwater habitats may be more severely affected by human activities than more stationary ones. Freshwater species are also consistently more threatened than their terrestrial counterparts. Reptiles, according to this study, are particularly at risk from extinction, with nearly half of all species threatened or near threatened. This makes reptiles the most threatened freshwater taxa considered in this analysis. The authors identified key process that were threatening freshwater species in this dataset – habitat degradation, water pollution and over-exploitation are the biggest risks. Habitat loss and degradation is the most common threat, affecting over 80% of threatened freshwater species.

That there was relatively little congruence between different taxa in the distribution of species richness and threatened species in freshwater ecosystems suggests that conservation planning that considers only one or a few taxa may miss crucial areas of conservation priority. For example, conservation planning rarely considers patterns of invertebrate richness, but if these groups are affected differently and in different regions than reptiles and amphibians, say, then they may be overlooked in initiatives that aim to protect them. Further, different ways to measure the health of populations and ecosystems yield different patterns. The metrics we use to identify threatened species, upon which conservation decisions are based, must be carefully considered if we are to suceeed in protecting valuable ecosystems and the services the provide.

Original Article:

() Global Ecology and Biogeography

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This research was made possible by funding from the Rufford Foundation and the European Commission

PREDICTS Project: Land-Use Change Doesn’t Impact All Biodiversity Equally

By Claire Asher, on 13 October 2014

Humans are destroying, degrading and depleting our tropical forests at an alarming rate. Every minute, an area of Amazonian rainforest equivalent to 50 football pitches is cleared of its trees, vegetation and wildlife. Across the globe, tropical and sub-tropical forests are being cut down to make way for expanding towns and cities, for agricultural land and pasture and to obtain precious fossil fuels. Even where forests remain standing, hunting and poaching are stripping them of their fauna, degrading the forest in the process. Habitat loss and degradation are the greatest threats to the World’s biodiversity. New research from the PREDICTS project investigates the patterns of species’ responses to changing land-use in tropical and sub-tropical forests worldwide. In the most comprehensive analysis of the responses of individual species to anthropogenic pressures to date, the PREDICTS team reveal strong effects of human disturbance on the geographical distribution and abundance of species. Although some species thrive in human-altered habitats, species that rely on a specific habitat or diet, and that tend to have small geographical ranges, are particularly vulnerable to habitat disturbance. Understanding the intricacies of how different species respond to different types of human land-use is crucial if we are to implement conservation policies and initiatives that will enable us to live more harmoniously with wildlife.

Red Panda (Ailurus fulgens)

Habitat loss and degradation causes immediate species losses, but also alters the structure of ecological communities, potentially destabilising ecosystems and causing further knock-on extinctions down the line. As ecosystems start to fall apart, the valuable ecosystem services we rely on may also dry up. There is now ample evidence that altering habitats, particularly degrading primary rainforest, has disastrous consequences for many species, however not all species respond equally to land-use change. The functional traits of species, such as body size, generation time, mobility, diet and habitat specificity can have a profound impact on how well a species copes with human activities. The traits that make species particularly vulnerable to human encroachment (slow reproduction, large body size, small geographical range, highly specific dietary and habitat requirements) are not evenly distributed geographically. Species possessing these traits are more common in tropical and sub-tropical forests, areas that are under the greatest threat from human habitat destruction and loss of vegetation over the coming decades. The challenge in recent years, therefore, has been developing statistical models that allow us to investigate this relationship more precisely, and collecting sufficient data to test hypotheses.

There are three key ways we might chose to investigate how species respond to land-use change. Many studies have investigated species-area relationships, which model the occurrence or abundance of species in relation to the size of available habitat. These studies have revealed important insights into the damage caused by habitat fragmentation, however they rarely consider how different species respond differently. Another common approach uses species distribution models to predict the loss of species in relation to habitat and climate suitability. These models can be extremely powerful, but require large and detailed datasets that are not available for many species, particularly understudied creatures such as invertebrates. The PREDICTS team therefore opted for a third option to investigate human impacts on species. The PREDICTS project has collated data from over 500 studies investigating the response of individual species to land-use change, and their database now includes over 2 million records for 34,000 species. Using this extensive dataset, the authors were able to model the relationship between land-use type and both the occurrence and abundance of species. One of the huge benefits of this approach is that their dataset enabled them to investigate these relationships in a wide range of different taxa, including birds, mammals, reptiles, amphibians and the often neglected invertebrates.

Modelling Biodiversity

Sunbear (Helarctos malayanus)
image used with permission from
Claire Asher (Curiosity Photographic)

The resulting model included the responses of nearly 4000 different species across four measures of human disturbance; lang-use type, forest cover, vegetation loss and human population density. The vast dataset, the PREDICTS team were able to compare the responses of species in different groups (birds, mammals, reptiles and amphibians, invertebrates, between habitat specialists and generalists and between wide- and narrow-raging species. Their results revealed a complex interaction between these factors, which influenced the occurrence and the abundance of species in different ways.

In general human-dominated habitats, such as urban and cropland environments, tended to harbour fewer species than more natural, pristine habitats. Community abundance in disturbed habitats was between 8% and 62% of the abundance found in primary forest, and urban environments were consistently the worst for overall species richness. In these environments, human population density and a lack of forest cover were key factors reducing the number of species. Human population density could impact species directly through hunting, or more indirectly through expanding infrastructure. However, these factors impact different species in different ways, so the authors next investigated different taxa separately.

Birds appear to be particularly poor at living in urban environments, most likely because they respond poorly to increases in human population. Forest specialists and narrow-ranged birds fare especially badly in urban environments; only 10% of forest specialists found in primary forest are able to survive in urban environments. Although the effect was less extreme, mammals were also less likely to occur in secondary forest and forest plantations than primary forest, and forest specialists were particularly badly affected.

Urban Pests
Although many species were unable to exist in disturbed habitats, those species that persisted were often more abundant in human-modified habitats than pristine environments. This isn’t particularly surprising – some species happen to possess characteristics that make them well suited to urban and disturbed landscapes; these are often the species that we eventually start to consider a pest because they are so successful at living alongside us (think pigeons, rats, foxes). These species tend to be wide-ranging generalists, although sometimes habitat specialists do well in human-altered habitats if we happen to alter the habitat in just the right. Pigeons, for example, are adapted to nesting on cliffs, which our skyscrapers and buildings inadvertently mimic extremely well. The apparent success of some species in more open habitats such as cropland and urban environments might also be partly caused by increased visibility – it’s far easier to see a bird or reptile in an urban environment than dense primary forest! This doesn’t explain the entire pattern, however, and clearly some species are simply more successful in human-altered habitats. They are in the minority, though.

Do Reptiles Prefer Altered Habitats?
One interesting finding was that for herptiles (reptiles and amphibians), more species were found in habitats with a higher human population density. This rather unexpected relationship might reflect a general preference in herptiles for more open habitats. Consistent with this, the authors found fewer species in pristine forest than secondary forest. However, upon closer inspection the authors found that herptiles do not all respond in the same way. Reptiles showed a U-shaped relationship with human population density – the occurrence of species was highest when there were either lots of people or no people at all. By contrast, amphibians showed a straight relationship, with increases in human population density being mirrored by increases in the number of species present. This highlights the importance of investigating fine-scale differences between species in their responses to human activities.

Filbert Weevil (Curculio occidentis)

Consistent with previous studies, the traits of species were very important in determining whether a species was found in human-altered habitats. Narrow-ranging species were much less likely to occur in any habitat than wide-ranging ones, but this difference was particularly clear for croplands, plantation forests and urban habitats. The extent of human impact was also a key factor determining the occurrence of species in different habitats. Forest cover, human population density and NDVI (a measure of vegetation loss taken from remote sensing) all reduced the number of species present. Measures of disturbance and species characteristics do not act in isolation – the best models produced by the PREDICTS team included interactions between these variables. Invertebrate numbers were lowest in areas of high human population density and high rates of vegetation loss.

This study is the first step in more detailed, comprehensive analyses of the responses of species to human activities. The power of this study comes not only from it’s large dataset and broad spectrum of taxonomic groups, but also from it’s ability to directly couple land-use changes with species’ traits such as range-size and habitat specialism. The authors say that the next major step would be to incorporate interactions between species in these models – the community structure of an ecosystem can have profound effects on the species living in it, and changes in the abundance of any individual species does not happen in isolation from the rest of the community.

Check out the PREDICTS Project for more information!

Original Article:

() Proc. R. Soc. B

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This research was made possible by funding from the Natural Environment Research Council (NERC), and the Biotechnology and Biological Sciences Research Council (BBSRC).

Extinction and Species Declines:
Defaunation in the Anthropocene

By Claire Asher, on 18 August 2014

We are in the grips of a mass extinction. There have been mass extinctions throughout evolutionary history, what makes this one different is that we’re the ones causing it. A recent review paper from GEE’s Dr Ben Collen discusses the current loss of biodiversity and suggests that our main concerns are species and population declines, which alter ecosystem dynamics and threaten our food, water and health. Understanding the drivers of local declines is more complex than understanding species extinction, but may be more pertinent to our ongoing health and survival.

The history of life on Earth has been punctuated by five mass-extinction events; from the Ordovician-Silurian extinction that killed 85% of sea life 443 million years ago, to the famous Cretaceous-Tertiary extinction that wiped out the dinosaurs 65 million years ago, mass extinctions have been a part of life. However, we are now in the middle of the sixth mass extinction event, and we’re the ones who are causing it. The last 500 years has seen humans cause a wave of extinctions of such speed and magnitude that it rivals the big five extinction events of the past.

Defaunation in the Anthropocene

Like other mass extinctions, the Anthropocene extinction event is affecting all taxonomic groups, although some are being hit harder than others. Since 1500, over 300 terrestrial vertebrates, 90 fish and nearly 400 are known to have been driven to extinction (although the real figures are likely much higher!). A conservative estimate suggests that we may be losing anywhere between 10,000 and 60,000 species each year. Many of these species go extinct before we ever even get a chance to identify them. Extinction is not evenly distributed, though – amphibians appear to be worse affected than birds, for example. Perhaps more worrying, many remaining species are suffering severe population declines. Globally, terrestrial vertebrate populations show declines of 25%, and 67% of monitored invertebrate populations are declining by 45%! The loss of species from ecosystems, either through local population declines or species extinction, will undoubtedly disrupt ecosystem function and the key ecosystem services humans rely on for survival and well being.

Scientists have coined the term ‘defaunation’ to include the extinction of species and populations as well as local declines in abundance. Defaunation can be thought of as deforestation for animals. It is an important point to make that although species extinctions are conspicuous and striking, the real damage to ecosystem function happens a long time before the final extinction event. Declines in populations will alter community composition far more than the final loss of the few remaining individuals of a population, and further, population declines have the potential to be reversed, if we act quickly enough!

Predicting Patterns of Defaunation

If we are to halt or even slow the current mass extinction, we need to identify both the causes of defaunation and the traits that make certain species so vulnerable to human disruption. The main drivers of defaunation are overexploitation of species, habitat destruction and introduced invasive species. These threats have all increased in severity over the past decade and look set to continue. In addition to these long-term threats, climate change is rapidly becoming the biggest threat to biodiversity. Most threatened species are under pressure from multiple human threats, but our understanding of the complex interactions and feedback loops between different threats is still in it’s infancy. It’s clear though that these threats do not act in isolation; a species trying to track suitable habitat as it moves with climate change will find that task much harder if habitat loss and fragmentation is also occurring.

Researchers have highlighted a number of life history and biological traits that tend to make species more vulnerable to human impacts. For example, species that have a small geographic range, large body size and produce just a few offspring after a long-development process, are more likely to be threatened with extinction due to human activities. However, our understanding of the traits that influence species’ extinction risk doesn’t help conservation as much as you might expect, because the relationship between these traits and extinction risk is often idiosyncratic and highly context-dependent. These relationships may also be more variable and weaker for individual populations than for whole species, making population declines more difficult to predict than whole-species extinctions. Defaunation, ultimately, is a synergistic function of the traits a species possess and the nature of the threat(s) it is exposed to.

Disrupting Ecosystems and Communities

The loss of biodiversity through defaunation is not just a concern because of the aesthetic appeal of an individual species, or of a world rich in diversity in general. It is also a major concern because defaunation will likely have a negative impact on the ecosystem goods and services upon which we rely upon for our wellbeing and survival. In fact, biodiversity loss is thought to be comparable to other threats such as pollution in terms of it’s impact on ecosystem function. Defaunation can be expected to have a negative impact on our food, water and health, as well as our psychological wellbeing.

Food

Insect pollination is required for the continued production of 75% of the World’s crops, and is responsible for 10% of the economic value of the entire World’s food supply. Declines in pollinators are now a major problem, particularly in Northern Europe and the USA, and have been linked to declines in insect-pollinated plants. Biodiversity, particularly of small vertebrates, is provides crucial pest control services, valued at around $4.5 billion a year in the USA alone. Declines in small vertebrate populations are linked to cascading changes in the whole ecosystem which allow increases in pest abundance and, consequently, a loss of plant biomass. If the plant in question is a crop or food source, the results can be catastrophic.

Nurtient Cycling and Decomposition

Invertebrates are also very important for their roles in decomposition and nutrient cycling. Defaunation can reduce these important services, and cause changes in the patterns of nutrient cycling that can have knock-on effects on a huge variety of ecosystems. Likewise, large vertebrates that roam large home ranges are important in connecting ecosystems and transferring energy between them, and yet these species are often the most severely impacted by human activities.

Water

Another key ecosystem service is the provision of clean, fresh water. Research has shown that declines in amphibian populations can result in increases in algae, reduced nitrogen uptake and changes to oxygen availability in the water. This too will likely have major knock-on effects for other species (including ourselves!).

Health and Medicine

Finally, we can expect defaunation to negatively affect our health. Species that are more robust to human disturbance are often also better at carrying and transmitting zoonotic diseases (diseases that are carried by animals and transferred to humans), and altering ecosystem dynamics can change behaviours that influence transmission rates. Defaunation is likely to also reduce the availability of pharmaceutical compounds and alter the dynamics of disease regulation. All of this may mean that defaunation leads to an increase disease and a reduction in the availability of therapeutic compounds.

The impact of defaunation is less about the absolute loss of biodiversity and more about the local shifts in species composition and functional groups, which alter ecosystem function and ultimately, our food, water and health. However, reductions in species exploitation and land-use change are two feasible actions that can be achieved rapidly and may buy us enough time to address other drivers of defaunation such as climate change. Globally, we need to reduce and more evenly distribute our consumption if we are to change current trends in defaunation, and open the possibility for refaunation.

Original Article:

() Science

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This research was made possible by funding from the Natural Environment Research Council (NERC), the National Council for Scientific and Technological Development (CNPQ), the Foundation for the Development of UNESP, the Sao Paolo Research Foundation, the Joint Nature Conservation Committee (JNCC), the National Science Foundation (NSF) and the National Autonomous University of Mexico/a>.

Predicting Extinction Risk:
The Importance of Life History and Demography

By Claire Asher, on 28 July 2014

The changing climate is no longer simply a concern for the future, it is a reality. Understanding how the biodiversity that we share our planet with will respond to climate change is a key step in developing long-term strategies to conserve it. Recent research by UCL CBER’s Dr Richard Pearson identifies the key characteristics that are likely to influence extinction risk due to climate change, and shows that existing conservation indicators such as the IUCN red list may contain the data necessary to make these predictions.

Human activities have been negatively impacting biodiversity for centuries, and conservationists have developed a number of different indicator lists which attempt to classify species’ extinction risk. However, these lists were created to measure human impacts such as as habitat loss, hunting and introduction of invasive species. These impacts will continue to be a major issue for biodiversity, but may be dwarfed in the future as climate change takes hold. Can the indices and data we already have be used to predict extinction risk from climate change? Or does climate change represent a new type of threat, needing new indices?

Studies have previously identified the ecological and biological traits that are characteristic of threatened or declining species. However, it is not clear how well these traits predict the future risk of climate-induced extinction. In February this year, GEE’s Dr Richard Pearson, in collaboration with colleagues at the American Museum of Natural History, Stony Brook University and the University of Adelaide, published a paper in Nature which attempted to address these questions. Most studies that have considered the impact of climate change on species’ extinctions have attempted to predict changes in the distribution of suitable habitats and measure extinction risk in terms of whether the species is likely to be able to find habitat to live in. However, such studies rarely consider how a species’ traits such as life history and spatial characteristics will influence their ability to persist through changes in climate. In this study, Pearson and colleagues coupled ecological niche models with demographic models, and developed a generic life history method to estimate extinction risk over the coming century.

Modelling Extinction
The authors then tested their models on ecological and spatial traits for 36 reptile and amphibian species in the USA. Using commonly available life history variables, they found that their models could accurately predict extinction risk between 2000 and 2010. They then utilised the same traits and models to predict future extinction risk under two climate models – a high emissions scenario and a policy scenario aimed at curbing emissions. Average extinction risk for the 36 species studied was 28% under the high emissions scenario, dropping to 23% under strict policy intervention. This seems like a very small difference for a significant intervention – it’s important to note that the same estimates indicated an average extinction risk of just 1% in the absence of any climate change at all.

One of the most important determinants of extinction risk in reptiles and amphibians was occupied area, which represents the range of climatic and habitat conditions the species can survive in. Species with a larger occupied area tended to be more robust to climate change, presumably because they are already adapted to a wider range of habitats and climates. Other key variables influencing extinction risk include population size and generation length. In many cases, traits interacted to determine species risk, for example extinction risk was strongly influenced by interactions between occupied area and generation length. Including many different traits can therefore greatly improve the accuracy of predictions. Recent trends tended to be less informative than spatial, demographic and life history traits, particularly under the high emissions scenario, suggesting that the impacts of climate change we have observed so far are likely to become less and less relevant as climate change accelerates.

The majority of variables that showed a significant impact on extinction risk are already included in major conservation assessments and indices, meaning that data and monitoring programs already in place may be better at predicting extinction risk under climate change than we might have expected. Climate change may not be fundamentally different from other human threats such as habitat loss and hunting, at least in terms of our ability to assess extinction risk. Conservation initiatives should focus on species who currently occupy a small and declining area and have a small population size. Regardless of the policy future, conservation actions will need to consider and account for climate change if they are to prove effective.

Original Article:

() Life History and Spatial Traits Predict Extinction Risk Due to Climate Change Nature

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This research was made possible by funding from the National Aeronautics and Space Administration (NASA) and the Australian Research Council

Synthetic Biology and Conservation

By Claire Asher, on 7 July 2014

Synthetic biology, a hybrid between Engineering and Biology, is an emerging field of research promising to change the way we think about manufacturing, medicine, food production, and even conservation and sustainability. Oryx front cover
A review paper released this month in Oryx, authored by Dr Kent Redford, Professor William Adams, Dr Rob Carlson, Bertina Ceccarelli and CBER’s Professor Georgina Mace, discusses the possibilities and consequences of synthetic biology for biodiversity conservation. Synthetic biology aims to engineer the natural world to generate novel parts and systems that can be used to tackle real world problems such as genetic disease, food security, invasive species and climate change. It’s implications are far reaching, and although research in synthetic biology began decades ago, conservation biologists have only recently begun to take notice and appreciate it’s relevance to the conservation of biological diversity. A conference organised by the Wildlife Conservation Society in 2013 discussed the relationship between synthetic biology and conservation, and included speakers from both fields.

Finding Common Ground
It might be surprising to find that, despite a similar background in biological research, the shared knowledge and language of conservationists and synthetic biologists is relatively limited. Further, many synthetic biologists come from an engineering background, with little training in ecology. This can make communication between scientists in these fields more difficult, and may have slowed the pace at which synthetic biology has interfaced with conservation science. The two disciplines also employ different methods and think about nature in different ways. Synthetic biology is largely conducted within large, highly controlled laboratory conditions, whilst ecologists work on complex, interrelated natural systems with a major social and political component. Conservationists, working in a high-stakes field and learning from past mistakes, tend to be quite risk-averse in their practice of conservation, whilst synthetic biologists, working in a new science with much to gain from experimentation, tend to be more in favour of taking large risks. They may also have different outlooks on the future of biodiversity – conservations tend to be more pessimistic about the future, mourning past biodiversity loss, whilst synthetic biologists have an upbeat attitude, envisaging the applications of exciting research. Despite these (extremely generalised) differences, the conference revealed interest and excitement on both sides about the possibility of collaborating, and a mutual appreciation that the major challenges of the Anthropocene are human influences on climate, biodiversity and ecosystems. Finding practical, long-lasting and safe solutions to the plethora of challenges currently facing humanity, is of mutual interest.

Mitigating Risks and Maximising Benefits
The possible applications of synthetic biology to conservation are many. Synthetic biology might enable us to develop more efficient methods of energy production, freeing up habitat to recover. It could mitigate the effects of greenhouse gas emissions by releasing carbon-consuming algae. It could revive extinct species such as mammoths and dodos in a process known as ‘de-extinction’. It could engineer coral that is tolerant to increases in ocean temperature and acidity, conditions which are predicted to worsen under climate change. It could help to control or eradicate invasive species. It could restore degraded land and water for agriculture, sparing the need to destroy more natural habitat. It could even create pesticide- and parasite-resistant bees that can continue to pollinate our crops generations into the future.

However, he potential risks of synthetic biology to conservation are as many as the potential benefits. The effects of synthetic biology on conservation could be direct, (e.g. engineering resistant species), or they could be indirect (e.g. changes in land use). These effects could be negative, for example, if they lead to land use change of primary habitat as has been associated with GMOs and biofuels. They could also be positive, for example if they reduce the impact of human activities, allowing habitat to recover to its natural state. Synthetic biology might lead to unexpected impacts on ecosystem dynamics and risks the unintended escape of novel organisms into open ecosystems. Releasing synthetically engineered organisms into wild environments could alter ecosystems, reduce natural genetic variability or lead to hybridisation events that might display native flora and fauna, and generate new invasive species. Synthetic biology might also distract attention and funds from more traditional conservation efforts, whilst attracting protest from human rights and environmental organisations. Both conservationists and synthetic biologists are conscious of these potential risks, and are committed to careful consideration on a case-by-case basis. Not all synthetic biology is the same; some could be of huge potential benefit to conservation and sustainability whilst carrying minimal risks, and it is these that we should pursue.

Original Article:

() Oryx

Technology for Nature?

By Claire Asher, on 16 June 2014

Many of our greatest technological advances have tended to mark disaster for nature. Cars guzzle fossil fuels and contribute to global warming; industrialised farming practices cause habitat loss and pollution; computers and mobile phones require harmful mining procedures to harvest rare metals. But increasingly, ecologists and conservation biologists are asking whether we can use technology to help nature. On 10th June 2014, UCL’s Center for Biodiversity and Environment Research (CBER) hosted academics from the National Museum of Natural History, Paris, the Zoological Society of London and the Natural History Museum, London for a workshop on “Technology for Nature”. The workshop formed part of a series of public debates and workshops organised in collaboration with the French Embassy, around the theme of the ‘State of Nature’.

Technology for Nature Workshop

The workshop discussed some of the latest technologies available to monitor biodiversity and how these might be harnessed in combination with citizen science to better understand the natural world around us. Citizen science, which engages members of the public in collecting and processing data about nature, is a powerful tool enabling scientists to collect much larger quantities of data on populations of key species. Citizen science projects not only provide biologists with vastly more data than they could ever hope to collect on their own, but it also serves to engage members of the public with the natural world, and raise awareness of key environmental issues.

Following the workshop, UCL also hosted an evening debate in collaboration with colleagues at the French Embassy, London. Professor Romain Julliard from the National Museum of Natural History, Paris, and Professor Kate Jones from UCL’s CBER discussed how new technologies can be used to understand and predict the impact of humans on the natural world, and whether these technologies can be used to inspire and engage the public with the environment around them.

Technology for Nature Debate

Professor Julliard is the Scientific Director of Vigie Nature, a project to monitor trends in various widespread species including butterflies, birds, bees and flowers, using citizen scientists in France. Professor Jones holds the chair of Ecology and Biodiversity at UCL and the Zoological Society of London, and has been involved in a number of projects utilising citizen scientists to monitor populations of bats both in the UK and across Europe. She started the iBats project, which uses volunteers to collect acoustic recordings of bat calls which a computer algorithm can then use to identify the species, and has used citizen science to process data from this project through Bat Detective.

The meeting last week brought together academics from a range of different institutions with a shared interest in monitoring biodiversity to better understand how humans are impacting upon it. We hope this will lead to new projects and collaborations to monitor biodiversity and gain vital data that is needed to assess and ultimately mitigate our impact on the animals and plants we share the planet with.

The Delicate Balance of Effect and Response

By Claire Asher, on 18 February 2014

We may not always be aware of it, but many wild plants, animals, fungi and even bacteria, provide crucial services to us which keep the ecosystems of Earth functioning. Environmental changes caused by human activities are now threatening many species, and those that cannot withstand these changes may be lost forever, potentially taking the services they provide away. New research from GEE and collaborators worldwide aims to improve our understanding of how the traits and evolutionary histories of species influence their ability to provide essential ecosystem services, and to persist in the face of ongoing environmental change.

The diverse array of species we share planet Earth with, and the complex ecosystems they form, are crucial to our continued survival and well being. Species and ecosystems provide a huge number of ‘ecosystem services’ – functions such as nutrient cycling, waste decomposition, pollination and food, to name just a few, which humans rely on. However, many species are now under threat from human activities like deforestation, hunting and pollution. Scientists are working to understand how species and ecosystems will respond to our continued activities in the future, and particularly how this may effect the vital ecosystem services upon which we rely. Recent research by GEE’s Prof. Georgina Mace, in collaboration with researchers from Cordoba National Univerity, Imperial College London, VU University, Yale University and CSIC, has attempted to develop a new framework for risk assessing the effect of human activities on ecosystem services.

The framework considers two key aspects of species: their effect on the generation of a specific ecosystem service (e.g. seed dispersal), and their response to specific environmental pressures (e.g. drought). Both the effect of a species and the response of a species are underpinned by its traits, and each is influenced not by a single trait but a combination of traits. The response of a species will determine it’s ability to survive and flourish through future environmental changes and to continue to provide it’s ecosystem effects. However, only a species’ response is the subject of natural selection, via changes to the underlying traits; the effect of a species is merely a biproduct of traits selected for their influence on survival. In this way, the aspects of a species’ biology upon which we rely are only indirectly influenced by natural selection, and will only be maintained if the traits that generate them are beneficial through the environmental changes we cause. The framework developed by GEE researchers and collaborators considers how the response of species to envinmental stressors interacts with the effect of that species on key ecosystem services, and whether species with a large effect are more or less vulnerable to environmental change.

A third key factor influencing the sensitivity of ecosystem system services is the evolutionary relationships between species providing them. Closely related species often share similar traits, which may or may not result in them having similar effects and responses. If this is the case, then ecosystems in which a particular service is provided by a group of closely related species may be more vulnerable to environmental change, since those species may well share similar responses, and be sensitive to similar environmental pressures. Although many species’ traits are known to be similar amongst related species, because effects and responses are each the result of a combination of traits, it is not known whether this relationship is also common for these variables.

The new framework developed by GEE’s Professor Georgina Mace and collaborators attempts to address this by incorporating evolutionary relationships (phylogeny) into their response-effect model, and applying this model to 5 case studies. The case studies cover 5 species assemblages including a total of 480 species in Europe, Central America and Africa, for which response and effects could be estimated based on past studies of species’ traits and vulnerabilities. The case studies tended to show a strong relationship between phylogeny and both species’ effects on ecosystem services and their responses to environmental stressors. This indeed suggests that ecosystem services that rely upon closely related groups of species may be most at risk from environmental change. Cases where effects and responses are negatively correlated, so that the most influential species in terms of a given ecosystem service are also the most vulnerable to environmental stress, are most vulnerable to loss of that ecosystem service through human activities. Whether this type of relationship is common in nature remains to be investigated by future studies, and this framework provides a powerful basis with which to do so.

Our relentless demands on the natural world are inevitably leading to new pressures and stresses on natural populations, and it is of great concern that these pressures may negatively impact on the vital ecosystem services that we rely upon, often without even realising it. Ecosystem services provide us with food and fresh water, decompose our waste, recycle nutrients and remove harmful toxins. Without them our continued survival and well being would be seriously compromised. Scientists are still working to understand how species’ traits influence their ability to provide ecosystem services and their resilience to ongoing environmmental change. A new framework developed in collaboration between universities in the UK, Spain, Argentina, the USA and the Netherlands is beginning to shed light on the interaction between species’ traits, their effect on ecosystem services and their response to environmental change, and how these factors are influenced by evolutionary relationships between species. This framework offers a powerful new view of how the traits of species within an ecosystem translate into the ecosystem services upon which we are so reliant, and future research building upon this framework promises to improve our understanding of ecosystem services and environmental change.

Original Article:

() Ecology and Evolution



This research was made possible by funding from the Natural Environment Research Council (NERC), the Leverhulme Trust, and the US National Science Foundation