Evaluating the efficacy of predator removal in a conflict-prone world

Authors: Robert J Lennox, Austin J Gallagher, Euan G Ritchie, and Steven J Cooke

Published in: Biological Conservation, volume 224 (August 2018)


Predators shape ecosystem structure and function through their direct and indirect effects on prey, which permeate through ecological communities. Predators are often perceived as competitors or threats to human values or well-being. This conflict has persisted for centuries, often resulting in predator removal (i.e. killing) via targeted culling, trapping, poisoning, and/or public hunts. Predator removal persists as a management strategy but requires scientific evaluation to assess the impacts of these actions, and to develop a way forward in a world where human-predator conflict may intensify due to predator reintroduction and rewilding, alongside an expanding human population.

We reviewed literature investigating predator removal and focused on identifying instances of successes and failures. We found that predator removal was generally intended to protect domestic animals from depredation, to preserve prey species, or to mitigate risks of direct human conflict, corresponding to being conducted in farmland, wild land, or urban areas. Because of the different motivations for predator removal, there was no consistent definition of what success entailed so we developed one with which to assess studies we reviewed. Research tended to be retrospective and correlative and there were few controlled experimental approaches that evaluated whether predator removal met our definition of success, making formal meta-analysis impossible. Predator removal appeared to only be effective for the short-term, failing in the absence of sustained predator suppression. This means predator removal was typically an ineffective and costly approach to conflicts between humans and predators.

Management must consider the role of the predator within the ecosystem and the potential consequences of removal on competitors and prey. Simulations or models can be generated to predict responses prior to removing predators. We also suggest that alternatives to predator removal be further developed and researched.

Ultimately, humans must coexist with predators and learning how best to do so may resolve many conflicts.

Lennox RJ, Gallagher AJ, Ritchie EG, Cooke SJ (2018) Evaluating the efficacy of predator removal in a conflict-prone world, Biological Conservation, PDF DOI

The Conversation: Killing sharks, wolves and other top predators won’t solve conflicts

Black tip sharks swim with tropical fish in a lagoon in French Polynesia.

By Robert Lennox (Carleton University), Austin Gallagher (University of Miami), Euan Ritchie (Deakin University) and Steven J Cooke (Carleton University).

This article was originally published on The Conversation. Read the original article.

In French Polynesia, fishing is an integral part of everyday life. The people living here fish on the flats and along the reef using nets, hooks and line, harpoons, spearguns and traditional artisanal traps.

They fish for food. They are also seeing the benefits of using their traditional knowledge to guide recreational fishing tourists — a business with potential to improve long term employment security.

Abundant sharks in the lagoon led to questions about their contribution to the fishery and whether it would help the fishery if they were targeted. This is a question that is often on the minds of humans when they encounter predators.

As an ecologist working with the fish populations in French Polynesia, I went looking for research about what happens to an ecosystem when a predator is removed. Are the responses predictable? Does it work? Can we make generalizations?

Our new study, published in Biological Conservation, surveyed the research on predator removal and identified several interesting — and perhaps unexpected — trends.

Humans and other predators

Predators are among the most charismatic animals on Earth — lions, eagles and sharks adorn many human symbols. On land, in the air and in water, predators fascinate and inspire, they are quintessential representations of nature’s majesty and might.

In spite of their ecological, economic and cultural significance, predators are among the most heavily persecuted animals, due to conflict with humans and their assets.

Predators attack and kill livestock, hunt economically important prey and can kill or injure people or be perceived as a threat to human safety. These conflicts may motivate humans to try to manage predators to lessen the damages.

One of the oldest and most rudimentary methods is to cull or remove them, even though predators are already rare and some are threatened with extinction.

The motivation to remove predators is easy to understand, but what if predator removal does not even achieve the desired outcomes?

In balance

Predators are essential to ecosystems because they regulate prey populations. Without predators, prey can become over-abundant. This can result in damage to local plants, as well as disease outbreaks that can spread to domesticated animals.

Top predators like wolves dominate small predators like coyotes, keeping those populations in check too. Without predators, ecosystems become unbalanced in many ways because plants, herbivores and small predators change in response to their loss.

In a perfect scenario, successful predator removal would strike a balance. It would reduce conflict and be sustainable, but not cause the predator population to disappear entirely. However, our review of 141 studies of predator removal revealed that success is rarely achieved.

Livestock attacks weren’t always reduced when predators were removed, and the human-wildlife conflict remained. On top of that, new predators often moved into vacated territory and recolonized areas where others had been removed. For example, when caracal (a type of wild cat) and leopard were culled in South Africa, predator conflicts on farms increased.

A small number of studies have shown successful removal of predators without harming the predator population, and led to increases in the prey population. However, these examples of success were generally from the Arctic where wolves were removed to increase caribou or moose numbers. In that scenario, there are fewer links in the food web, possibly making responses more predictable.

Generally, however, the responses were unpredictable and removing predators often failed for one reason or another.

Coexistence, not conflict

Ecosystems are complex networks of species. They include plants, decomposers, naturally subordinate predators (such as feral cats, foxes and coyotes), pathogens, predators and their prey. Together, they all play vital roles in regulating each other.

When humans remove predators, the effects are consistently negative. The action can, for example, fracture wolf packs into smaller units, or increase the reproductive rates of coyotes to produce even more offspring. This can have knock on effects, including an increase in disease, plant damage if herbivore populations explode and even an increase in the number of collisions between large herbivores, such as moose, and vehicles.

Instead of killing predators, there are other measures we can take to reduce conflict and learn to live with wildlife. In parts of Alberta, biologists are encouraging landowners to use electric fencing around bee hives and chicken coops to fend off bears. These types of non-lethal solutions can be tested and may often be more effective than removing the predator.

Other studies have suggested that “rewilding” an ecosystem — that is, reintroducing species into the ecosystem — can reduce conflicts. When their prey are abundant, the predators have less interest in nearby livestock. One study showed that lynx conflict with farmers increased when their natural prey, roe deer, were scarcer.

Essential elements

Instead of removing predators to manage human-wildlife conflict, we should be looking towards non-lethal alternatives. Using deterrent devices (lights, sounds or flapping material) can keep predators away from homes, fields and livestock.

The services that predators and functioning ecosystems provide to humans are of enormous value, and we would be wise to work hard to conserve and maintain them for the benefit of all.

Predators aren’t only symbols, they are essential parts of healthy terrestrial and aquatic landscapes. And beyond what we value, we should feel an imperative to preserve the diversity of life we share Earth with, most of which precedes our own evolution.

Of course, there will be times when predator removal may be necessary to protect people and their interests. Interventions that champion the principles of coexistence between humans and predators may be more successful and justifiable approaches to managing wildlife.

Efforts to protect predators or proactively promote their return, rather than continue contributing to their decline and extinction, are among the greatest conservation challenges we face.
The Conversation

Crowdfunded campaigns are conserving the Earth’s environment

Crowdfunded campaigns to save the orange-bellied parrot are a rare ray of hope. Image credit: Fatih Sam

By Eduardo Gallo-Cajiao (University of Queensland), Carla Archibald (University of Queensland), Euan Ritchie (Deakin University), Rachel Friedman (University of Queensland), Richard Fuller (The University of Queensland), Rochelle Steven (University of Queensland), and Tiffany Morrison (James Cook University)

This article was originally published on The Conversation. Read the original article, including reader comments.

If not for the public’s generosity, the iconic Statue of Liberty might not have the solid and impressive footing she does today. In the late 1800s, government funds for the monument were exhausted. Yet through a fundraising campaign, the New York World newspaper garnered support from over 160,000 residents to cover the pedestal costs.

Just as large monuments need solid bases to ensure their long-term existence, so too does the environment. In the case of nature conservation, it requires money to support diverse research projects, on-ground activities, and outreach aimed at protecting and managing species and habitats.

While the health of the environment continues to decline globally, in most regions government funding falls short of what is required to stem the losses. Crowdfunding plays an important and under-appreciated role for biodiversity conservation.

Our new research presents a global analysis of how crowdfunding, still a relatively novel and minor financial mechanism in the conservation community, is contributing to conservation around the world.

Show me the money. What’s being funded and why?

Crowdfunding offers a powerful mechanism for mobilising resources for conservation across borders. We recorded 577 conservation-oriented projects (from 72 crowdfunding platforms), which have raised around US$4.8 million since 2009. The people leading these projects were based in 38 countries, but projects took place across 80 countries.

This pattern has important implications for conservation, because there is often a mismatch between high-priority areas for global conservation and countries with the greatest financial and technical capacity. For instance, we discovered that a third of the projects were delivered in different countries to where their proponents were based. The USA, UK and Australia were the countries with the highest outflow of projects (“project exporters”). Indonesia, South Africa, Costa Rica and Mexico had the highest inflow (“project importers”).

Crowdfunding could be supporting conservation work of actors that do not have as much capacity for raising funds.

The people leading projects were primarily from non-governmental organisations (35%) or universities (30%), or were freelancers (26%). Importantly, among non-governmental organisations, we discovered organisations operating at sub-national levels proposed a majority of projects.

Additionally, crowdfunding for conservation is not all about research. While most of the projects we reviewed focused on research (40%), many tackled raising awareness of conservation-related issues (31%) or boots-on-the-ground activities (21%). This expands the sphere of anecdotal evidence and commentary about crowdfunding related to conservation, which has so far revolved around research. For the first time, we’ve systematically unpacked how these funds are being used for additional activities to support conservation.

Crowdfunding can also support innovative projects that traditional funding agencies deem too risky or unconventional. For example, one project supported buying and training two Maremma sheepdogs to protect penguins against predatory foxes in southeastern Australia. (That might sound familiar to those who’ve seen the movie Oddball.)

Such opportunities for innovation can have important consequences for conservation worldwide; crowdfunding could be considered an incubator for novel ideas before widespread dissemination.

More than half of the projects we recorded (around 58%) largely focused on species. These included a disproportionate number of threatened bird and mammal species.

Prominent projects to save orange-bellied parrots or Papua New Guinea’s endangered tree kangaroos are important success stories.

This is not to underplay crowdfunding’s importance for ecosystems – whether land-based (20%), marine (9%) or freshwater (4%). Crowfunding is supporting projects ranging from protection of wilderness areas in remote Tasmania to research informing the conservation of the Californian coast.

Crowdfunding benefits extend beyond dollars and cents

The amount of money for conservation via crowdfunding has so far been relatively modest compared to more traditional conservation finance mechanisms. However, the benefits of crowdfunding extend well beyond dollars and cents. Crowdfunding helps communicate environmental issues and empower researchers and communities.

The figure below shows the reach of a single tweet during the Big Roo Count campaign. It shows how conservation-related messages can spread widely and engage communities via social media.

Crowdfunding is an exciting new tool in the conservation toolbox. But, ultimately, traditional funding sources, like government agencies, still have a major role and duty to invest adequately in environmental protection and nature conservation. Considering the current extinction crisis, governments must avoid further outsourcing of such responsibilities.

The discussion over novel sources and recipients of conservation funding continues. At the same time, transparency and oversight remain critical for managing expectations and overall effectiveness of funding. Crowdfunding contributes one more building block to democratising conservation funding and increasing transparency.

The authors would like to acknowledge the contribution of Edward Game.
The Conversation

Crowdfunding biodiversity conservation

Authors: Eduardo Gallo-Cajiao, Carla Archibald, Rachel Friedman, Richard A Fuller, Edward T Game, Tiffany Morrison, and Euan G Ritchie

Published in: Conservation Biology


Raising funds is critical for conserving biodiversity and hence so too is scrutinizing emerging financial mechanisms that might help achieve this goal. In this context, anecdotal evidence indicates crowdfunding is being used to support a variety of activities needed for biodiversity conservation, yet its magnitude and allocation remain largely unknown.

We conducted a global analysis to help address this knowledge gap, based on empirical data from conservation‐focused projects extracted from crowdfunding platforms. For each project, we determined the funds raised, date, country of implementation, proponent characteristics, activity type, biodiversity realm, and target taxa.

We identified 72 relevant platforms and 577 conservation‐focused projects that have raised US$4,790,634 since 2009. Whilst proponents were based in 38 countries, projects were delivered across 80 countries, indicating a potential mechanism of resource mobilization. Proponents were from non‐governmental organizations (35%), universities (30%), or were freelancers (26%). Most projects were for research (40%), persuasion (31%), and on‐ground actions (21%). Projects have focused primarily on species (57.7%) and terrestrial ecosystems (20.3%), and less on marine (8.8%) and freshwater ecosystems (3.6%). Projects have focused on 208 species, including a disproportionate number of threatened bird and mammal species.

Crowdfunding for biodiversity conservation has now become a global phenomenon and presents signals for potential expansion, despite possible pitfalls. Opportunities arise from its spatial amplifying effect, steady increase over time, inclusion of Cinderella species, adoption by multiple actors, and funding of a range of activities beyond research.

Our study paves the way for further research on key questions, such as campaign success rates, effectiveness, and drivers of adoption. Even though the capital input of crowdfunding so far has been modest compared to other conservation finance mechanisms, its contribution goes beyond funding research and providing capital.

Embraced with due care, crowdfunding could potentially become an increasingly important financial mechanism for biodiversity conservation.

Gallo-Cajiao E, Archibald C, Friedman R, Steven R, Fuller RA, Game ET, Morrison TH, Ritchie EG (2018) Crowdfunding biodiversity conservation, Conservation Biology PDF DOI

Animal recognition and identification with deep convolutional neural networks for automated wildlife monitoring

Authors: Hung Nguyen, Sarah J Maclagan, Tu Dinh Nguyen, Thin Nguyen, Paul Flemons, Kylie Andrews, Euan G Ritchie, and Dinh Phung

Published in: 2017 IEEE International Conference on Data Science and Advanced Analytics


Efficient and reliable monitoring of wild animals in their natural habitats is essential to inform conservation and management decisions. Automatic covert cameras or “camera traps” are being an increasingly popular tool for wildlife monitoring due to their effectiveness and reliability in collecting data of wildlife unobtrusively, continuously and in large volume. However, processing such a large volume of images and videos captured from camera traps manually is extremely expensive, time-consuming and also monotonous. This presents a major obstacle to scientists and ecologists to monitor wildlife in an open environment.

Leveraging on recent advances in deep learning techniques in computer vision, we propose in this paper a framework to build automated animal recognition in the wild, aiming at an automated wildlife monitoring system. In particular, we use a single-labeled dataset from Wildlife Spotter project, done by citizen scientists, and the state-of-the-art deep convo- lutional neural network architectures, to train a computational system capable of filtering animal images and identifying species automatically.

Our experimental results achieved an accuracy at 96.6% for the task of detecting images containing animal, and 90.4% for identifying the three most common species among the set of images of wild animals taken in South-central Victoria, Australia, demonstrating the feasibility of building fully automated wildlife observation. This, in turn, can therefore speed up research findings, construct more efficient citizen science- based monitoring systems and subsequent management decisions, having the potential to make significant impacts to the world of ecology and trap camera images analysis.

Nguyen H, Maclagan SJ, Nguyen TD, Nguyen T, Flemons P, Andrews K, Ritchie EG, Phung D (2017) Animal recognition and identification with deep convolutional neural networks for automated wildlife monitoring, 2017 IEEE International Conference on Data Science and Advanced Analytics PDF DOI 

From drone swarms to tree batteries, new tech is revolutionising ecology and conservation

Eyes in the sky: drone footage is becoming a vital tool for monitoring ecosystems. Image credit: Deakin Marine Mapping Group

By Euan Ritchie and Blake Allen, Deakin University

This article was originally published on The Conversation. Read the original article, including reader comments.

Understanding Earth’s species and ecosystems is a monumentally challenging scientific pursuit. But with the planet in the grip of its sixth mass extinction event, it has never been a more pressing priority.

To unlock nature’s secrets, ecologists turn to a variety of scientific instruments and tools. Sometimes we even repurpose household items, with eyebrow-raising results – whether it’s using a tea strainer to house ants, or tackling botfly larvae with a well-aimed dab of nail polish.

But there are many more high-tech options becoming available for studying the natural world. In fact, ecology is on the cusp of a revolution, with new and emerging technologies opening up new possibilities for insights into nature and applications for conserving biodiversity.

Our study, published in the journal Ecosphere, tracks the progress of this technological development. Here we highlight a few examples of these exciting advances.

Tiny tracking sensors

Electronically recording the movement of animals was first made possible by VHF radio telemetry in the 1960s. Since then even more species, especially long-distance migratory animals such as caribou, shearwaters and sea turtles, have been tracked with the help of GPS and other satellite data.

But our understanding of what affects animals’ movement and other behaviours, such as hunting, is being advanced further still by the use of “bio-logging” – equipping the animals themselves with miniature sensors.

Many types of miniature sensors have now been developed, including accelerometers, gyroscopes, magnetometers, micro cameras, and barometers. Together, these devices make it possible to track animals’ movements with unprecedented precision. We can also now measure the “physiological cost” of behaviours – that is, whether an animal is working particularly hard to reach a destination, or within a particular location, to capture and consume its prey.

Taken further, placing animal movement paths within spatially accurate 3D-rendered (computer-generated) environments will allow ecologists to examine how individuals respond to each other and their surroundings.

These devices could also help us determine whether animals are changing their behaviour in response to threats such as invasive species or habitat modification. In turn, this could tell us what conservation measures might work best.

Autonomous vehicles

Remotely piloted vehicles, including drones, are now a common feature of our skies, land, and water. Beyond their more typical recreational uses, ecologists are deploying autonomous vehicles to measure environments, observe species, and assess changes through time, all with a degree of detail that was never previously possible.

Coupling autonomous vehicles with sensors (such as thermal imaging) now makes it easier to observe rare, hidden or nocturnal species. It also potentially allows us to catch poachers red-handed, which could help to protect animals like rhinoceros, elephants and pangolins.

3D printing

Despite 3D printing having been pioneered in the 1980s, we are only now beginning to realise the potential uses for ecological research. For instance, it can be used to make cheap, lightweight tracking devices that can be fitted onto animals. Or it can be used to create complex and accurate models of plants, animals or other organisms, for use in behavioural studies.


Keeping electronic equipment running in the field can be a challenge. Conventional batteries have limited life spans, and can contain toxic chemicals. Solar power can help with some of these problems, but not in dimly lit areas, such as deep in the heart of rainforests.

“Bio-batteries” may help to overcome this challenge. They convert naturally occurring sources of chemical energy, such as starch, into electricity using enzymes. “Plugging-in” to trees may allow sensors and other field equipment to be powered cheaply for a long time in places without sun or access to mains electricity.

Combining technologies

All of the technologies described above sit on a continuum from previous (now largely mainstream) technological solutions, to new and innovative ones now being trialled.

Emerging technologies are exciting by themselves, but when combined with one another they can revolutionise ecological research. Here is a modified exerpt from our paper:

These advancements will not only generate more accurate research data, but should also minimise the disturbance to species and ecosystems in the process.

Not only will this minimise the stress to animals and the inadvertent spread of diseases, but it should also provide a more “natural” picture of how plants, animals and other organisms interact.

Realising the techno-ecological revolution will require better collaboration across disciplines and industries. Ecologists should ideally also be exposed to relevant technology-based training (such as engineering or IT) and industry placements early in their careers.

The ConversationSeveral initiatives, such as Wildlabs, the Conservation Technology Working Group and TechnEcology, are already addressing these needs. But we are only just at the start of what’s ultimately possible.
The Conversation

Futurecasting ecological research: the rise of technoecology

Authors: Blake M Allan, Dale G Nimmo, Daniel Ierodiaconou, Jeremy VanDerWal, Lian Pin Koh, and Euan G Ritchie

Published in: Ecosphere, volume 9, issue 5 (May 2018)


Increasingly complex research questions and global challenges (e.g., climate change and biodiversity loss) are driving rapid development, refinement, and uses of technology in ecology. This trend is spawning a distinct sub‐discipline, here termed “technoecology.”

We highlight recent ground‐breaking and transformative technological advances for studying species and environments: bio‐batteries, low‐power and long‐range telemetry, the Internet of things, swarm theory, 3D printing, mapping molecular movement, and low‐power computers. These technologies have the potential to revolutionize ecology by providing “next‐generation” ecological data, particularly when integrated with each other, and in doing so could be applied to address a diverse range of requirements (e.g., pest and wildlife management, informing environmental policy and decision making).

Critical to technoecology’s rate of advancement and uptake by ecologists and environmental managers will be fostering increased interdisciplinary collaboration. Ideally, such partnerships will span the conception, implementation, and enhancement phases of ideas, bridging the university, public, and private sectors.

Allan BM, Nimmo DG, Ierodiaconou D, VanDerWal J, Koh LP, Ritchie EG (2018) Futurecasting ecological research: the rise of technoecology, Ecosphere PDF DOI