Carson’s Call: An Inspiration for Ecologists Working in a Post-Truth World

Post provided by Will Pearse

Rachel Carson (1940) Fish & Wildlife Service employee photo.

Rachel Carson (1940) Fish & Wildlife Service employee photo.

I can’t think of a more inspirational and influential ecologist than Rachel Carson. Nearly fifty years ago she released a book called Silent Spring, which argued that pesticides such as DDT were cascading up through food chains causing the death or sterilisation of birds and other animals. The publication of her book provoked public debate, likely in part because it was serialised in The New Yorker, and led to a paradigm shift in US and (arguably) global pest control policy.

With the full support of the scientific community to verify her facts and arguments, she was able to defeat the chemical industry’s backlash and galvanise public opinion in her favour. The 2005 Stockholm Convention, in which DDT was banned from agricultural use, would likely have never happened if it were not for her work.

“In a post-truth world where trust in the scientific process is being eroded almost daily, Rachel Carson is a perfect example of how we can speak out and be heard while still being scientists.”

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Biomonitoring Pollution in Wetlands: A New Method for More Reliable Interpretation of Chemical Data

Post provided by Mark Gillingham and Fabrizio Borghesi

Wetlands tend to accumulate considerable anthropogenic pollution.

Wetlands tend to accumulate considerable anthropogenic pollution.

All living organisms are dependent on trace elements (TEs), including metals, that are acquired in very small quantities through their environment or diet. Most TEs are essential for growth, development and physiology of the organism, but excessive intake can be detrimental for animals and plants.  Some TEs – especially heavy metals such as mercury, cadmium, lead and others – are generally toxic though. This toxicity occurs because species’ natural mechanisms fail to excrete excess TEs quickly enough for their metabolism to cope. TEs are present in the environment at different concentrations, either through natural processes or anthropogenic processes (i.e. pollution).

Since the industrial revolution, pollution from human activities has dramatically increased the concentrations of TEs in the natural environment. TEs from pollution tend to persist for a long time on the top layer of soils and sediments, because they do not undergo microbial degradation. As a consequence they tend to enter the food web quicker than the same elements of natural origin.

Some natural environments are more vulnerable to toxic effects of TEs. For instance, wetlands are geochemical endpoints of large river systems that often flow near or through cities, roads, factories, industries, cultivated lands, and/or mines, so they tend to accumulate considerable anthropogenic pollution. Vulnerable habitats like wetlands need to be closely monitored in order to assess the environmental health of these ecosystems. For this kind of monitoring we need reliable methods to measure TEs exposure, intake and bioaccumulation. Continue reading

Lichens and the “health” of ecosystems: we are closer to a global ecological indicator

Below is a press release about the Methods paper ‘Tracking global change using lichen diversity: towards a global-scale ecological indicator‘ taken from the University of Lisbon.

Candelaria pacifica. © Paula Matos

Candelaria pacifica. © Paula Matos

For the first time, it is possible to integrate at the global scale the results obtained with the most widely used methods to evaluate the “health” of ecosystems using lichens. This is the result of a study now published in the journal Methods in Ecology and Evolution, and represents a fundamental step for this indicator to be considered at the global scale and included in the list of indicators of the United Nations.

Lichens have long been successfully used by scientists as ecological indicators – a kind of environment health thermometer. These complex organisms – the yellow or green taints we often see on the surface of tree trunks – are very sensitive to pollution and changes in temperature and humidity. Evaluating how many lichens, of what kind, and their abundance in a certain ecosystem allows scientists to understand the impact that problems like climate change or pollution have on those ecosystems.  Continue reading

Just snap it! Using Digital Cameras to Discover What Birds Eat

Post provided by Davide Gaglio and Richard Sherley

Digital photography has revolutionised the way we view ourselves, each other and our environment. The use of automated cameras (including camera traps) in particular has provided remarkable opportunities for biological research. Although mostly used for recreational purposes, the development of user-friendly, versatile auto-focus digital single lens reflex (DSLR) cameras allows researchers to collect large numbers of high quality images at relatively little cost.

These cameras can help to answer questions such as ‘What does that species feed its young?’ or ‘How big is this population?’, and can provide researchers with glimpses of rare events or previously unknown behaviours. We used these powerful research tools to develop a non-invasive method to assess the diets of birds that bring visible prey (e.g. prey carried in the bill or feet) back to their chicks. Continue reading

Lasers in the Jungle Somewhere: How Airborne LiDAR Reveals the Structure of Forests

Post provided by Phil Wilkes (PDRA, Department of Geography, University College London)

Like an X-ray, airborne LiDAR allows you to peer through the dense canopy, revealing the structure of the forest beneath. ©Robert Kerton, CSIRO

Like an X-ray, airborne LiDAR allows you to peer through the dense canopy, revealing the structure of the forest beneath. ©Robert Kerton, CSIRO

How many samples do you hope to collect on your next field assignment? 50, 100 or 1000? How about billions. It may seem overly optimistic, but that’s the reality when using Light Detection and Ranging, or LiDAR.

LiDAR works on the principle of firing hundreds of thousands of laser pulses a second that measure the distance to an intercepting surface. This harmless barrage of light creates a highly accurate 3D image of the target – whether it’s an elephant, a Cambodian temple or pedestrians walking down the street. LiDAR has made the news over recent years for its ability to unearth ancient temples through thick jungle, but for those of us with an ecological motive it is the otherwise impenetrable cloak of vegetation which is of more interest.

Airborne LiDAR in Forests

As it’s National Tree Week in the UK, the focus of this blog post will be on the application of LiDAR in forests. There are a number of techniques that use LiDAR in forests, across a range of scales, from handheld, backpack and tripod mounted terrestrial laser scanners to spaceborne instruments on the International Space Station. Continue reading

Can We Really Measure Habitat Condition From Space?

Post provided by Tom Harwood, Randall Donohue, Simon Ferrier, Tim McVicar, Graeme Newell, Matt White and Kristen Williams

Remotely sensing can see patterns of land cover, but how do we use this information to quantify human impact on biodiversity?

Remotely sensing can see patterns of land cover, but how do we use this information to quantify human impact on biodiversity? ©NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team

It’s very hard to make sensible choices without sensible information. When it comes to actions around changing land use and its ecological impact though, this is often what we are forced to do. If we want to reduce the impact of human activities on natural ecosystems, we need to know how much change has already occurred and how altered an ecosystem might be from its “natural” state.

Working out which parts of the landscape have been changed and mapping the absence of natural vegetation is an achievable (though onerous) task. However, moving beyond this binary view of the world is a huge challenge. Pretty much all habitat has been modified by human influences to some extent – by, for example, wood extraction, the introduction of invasive species or livestock grazing. This means that a lot of the apparently native habitat is no longer capable of supporting its full complement of native biodiversity. Continue reading

Testing the Effects of Underwater Noise on Aquatic Animals

Post provided by Karen de Jong

Most people assume that research equipment is expensive and complicated. But, it doesn’t need to be and the noise egg is a perfect example of this. It consists of a watertight container (as used by scuba divers) and the buzzer from a cellphone and does exactly what it says: it produces low frequency noise. This allows researchers to test the effect of noise on underwater life. It is a small, simple and cheap device that anyone can build.

Why Test Effects of Noise?

A painted goby in front of his nest ©K. de Jong

A painted goby in front of his nest ©K. de Jong

Underwater noise is rapidly increasing due to, for example, boat traffic and offshore wind farms. This can lead to stress for animals and difficulties in communication. Just as people have a hard time communicating in a noisy pub, animals may struggle to get their messages across when background noise is high. A nice description of how animals use sound and how noise may affect this can be found at

While there is some knowledge on the effect of noise on large aquatic animals, we still know very little about how fish and other small aquatic animals are affected. Such knowledge is vital for management of protected areas. It’s also important to know whether wind farms and boat traffic can affect reproduction in populations of underwater resources such as fish and mussels. The answers to these questions are likely to be species specific, so we’ll need data on a large number of species in different habitats. Continue reading

Exploring Microbial Diversity: From the Sequence to the Cell

Post provided by Ruben Props, Michelle Berry, Marian Schmidt, Frederiek-Maarten Kerckhof, Vincent Denef and Nico Boon

Searching Lake Michigan (USA) for uncharacterized microbial diversity. © Michelle Berry

Searching Lake Michigan (USA) for uncharacterized microbial diversity. © Michelle Berry

Exploring microbial diversity and relating it to ecosystem functions is one of the primary occupations of microbiologists and microbial ecologists worldwide. Unfortunately, recent studies have shown that the microbial census is far from complete and that it is heavily biased towards certain (host-associated) environments. With the Earth’s microbial diversity estimated at an impressive one trillion (1012) taxa, the search continues for new technologies and methodologies that may help us better describe, monitor and preserve the microbial diversity of our planet’s natural and engineered ecosystems.

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Creating Bigger, Better and More Joined-up Habitat Networks

Below is a press release about the Methods paper ‘How to manipulate landscapes to improve the potential for range expansion‘ taken from the University of Liverpool.



Scientists at the University of Liverpool have developed a new ‘route planner’ tool that could help conservationists aid the movement of species as they adapt to a changing climate.

The environmental ranges of many animal and plant species are starting to alter with climate change, as temperatures change and force species to migrate to more suitable climes.

To be able to do this successfully, they will need sufficient habitat in their existing range, their future range, and any intermediate areas to enable populations to survive and thrive. Many conservation initiatives to restore habitats and increase connectivity are trying to address this issue. However, existing modelling tools mainly treat the landscape as static, and it is difficult to use these to plan restoration. Continue reading

Planning Habitat for Very Long-Distance Connectivity under Climate Change

Post provided by JENNY HODGSON

Climate change and habitat fragmentation are interacting threats: it is likely that many species cannot reach newly suitable areas at the cool edge of their range because there is not enough habitat, in the right places, to support range expansion over multiple generations. Conservation efforts are already underway to restore large areas of habitat, and to improve the “connectivity” within networks of habitat. However, there are multiple ways of measuring connectivity and few of them address the scale of shifts that are likely to be needed under climate change. This could be a problem if it leads to inefficient conservation prioritisation.

The Conductance Metric

How conductance generally depends on the amount of habitat in the landscape. Squares show the conductance of landscapes with a random selection of cells chosen to be habitat. The red line is based only on the 100% point and the expectation that conductance is proportional to amount of habitat squared.

How conductance generally depends on the amount of habitat in the landscape. Squares show the conductance of landscapes with a random selection of cells chosen to be habitat. The red line is based only on the 100% point and the expectation that conductance is proportional to amount of habitat squared.

We first developed the conductance metric in 2012 and we found that it is correlated to the speed with which a species can spread through a landscape, from a specified source location to a specified target. A key difference between this and most other connectivity metrics is that it incorporates both reproduction within habitat patches and dispersal between habitat patches, over multiple generations (further explanation here). Sometimes there could be many very well-connected patches in a network, and yet no easy way for a species to cross the landscape from end to end. This could be a problem for the species’ survival, if staying within its current regions of occupancy is unsustainable, for example if it is being pushed northwards by climate change. Continue reading