How we tracked the eating habits of snakes in Africa with the help of a Facebook group



A boomslang eating a bullfrog.
Provided by author/ G Cusins

Bryan Maritz, University of the Western Cape and Robin Maritz, University of the Western Cape

Snakes are a diverse lineage of reptiles that are found on every continent except Antarctica. Despite differences in appearance, habitat preference, defence tactics and underlying biology, one thing is common to all 3,800 species of snakes — every last one is a predator.

Pasha 75: Facebook helped us to learn what snakes eat. Why this is important.
The Conversation Africa, CC BY-NC-ND7.04 MB (download)

As predators, snakes are likely to fulfil important roles in ecosystems. Knowing what snakes eat can help scientists better understand ecological connections among snakes and other species. This will lead to a better understanding of how ecosystems function and how ecological communities might be affected by changes in habitat or climate.

Some snake species have also evolved potent venoms which aid in subduing prey. Mounting evidence suggests venom composition is adaptive and linked to what snakes eat. Although snake venoms have evolved primarily for feeding, venomous snakes also bite defensively.

Incidents of snake bites on people prompted the World Health Organisation to declare snakebite a neglected tropical disease in 2017. Given the link between venom biochemistry and feeding, a detailed understanding of a species’ diet can inform research dedicated to mitigating the effects of snakebite.

Unfortunately, the details of many African snake diets remain a mystery. Historically, information on snake diets has come from dissecting preserved museum specimens or fortuitous observations of snake feeding that are published as brief notes in journals or newsletters.

More recently, methods for studying snake feeding habits have embraced technology. These include fixed videography studies of ambush predators like puff adders and timber rattlesnakes, as well as DNA analysis of faecal material from smooth snakes. But these approaches cannot be used for many snake species, and they require a significant amount of time, effort, and resources.

Snake diets can be difficult to study, so, in 2015 we realised that photographs and videos of snakes feeding were being shared regularly on Facebook. We set out to gather these observations using a dedicated Facebook group – Predation Records – Reptiles and Frogs (Sub-Saharan Africa) – and to record the shared observations systematically. Our findings showcase how the network of active users on Facebook can help us to collect ecological data quickly and cheaply.

Our study

After several years of community participation in our study, we turned more than 1,900 observations of reptiles or amphibians eating or being eaten into scientific data. Our database includes 83 families of predators and 129 families of prey.

For snakes, we gathered more than 1,100 feeding records. We soon saw that social media had helped gather these feeding records faster than ever before. The data collected from Facebook represent 27% of scientifically documented snake feeding records in southern Africa. More than 70% of all feeding records had not been recorded previously in the scientific literature.

A snake eating a bird.
A boomslang eating woodpecker chick.
Provided by author/ L Van Wyk

To find out how data from social media compared to data collected using other platforms, we used iNaturalist (a popular citizen science platform) and Google Images to find observations of feeding snakes. Facebook outperformed both platforms in terms of the overall number of observations collected.

Finally, we noticed that observations collected from the different platforms produced different prey profiles, suggesting that certain prey may be over – or underrepresented in studies depending on the source of the observation.

Nearly all methods used for studying snake diets have biases. This may be why there are striking difference between what social media and the existing scientific literature revealed.

Facebook also let us identify prey more precisely. Most of the prey was photographed while being eaten or after regurgitation. On the other hand, prey collected from the stomachs of museum specimens are often partially digested, making the identification process difficult.

Our findings highlight the remarkable power of citizen science to reveal undocumented details about the natural world. In the case of snake diets, specifically, it is the harnessing of thousands of social media users that facilitated the data collection.

This is mainly because snakes feed secretively and relatively infrequently in the wild. But social media and the widespread use of smartphones with cameras means that even difficult to observe events can now be recorded in large numbers and across different geographic areas.

The continued detection of new feeding interactions shows how there is much to be learned about these remarkable animals. As more observations are made, the full picture of a species’ diet will be revealed. By using a community of observers, more data and information can be gathered for little to no cost.

Going forward

While our study was restricted to southern Africa, expanding data collection efforts like this into the rest of Africa is necessary. Given that Africa experiences some of the world’s heaviest snakebite burden, details on the biology of its snakes will prove useful. If ever there was an opportunity to gather novel, important ecological information about snakes in Africa, this is it.

Globally, there are hundreds of groups on Facebook – some of which have close to 200,000 members – dedicated to sharing original photographs and observations of snakes. More generally, Facebook groups exist for most classes of animals and plants, and these communities have unprecedented observational power for researchers asking appropriate questions of the natural world.The Conversation

Bryan Maritz, Senior Lecturer, Biodiversity and Conservation Biology, University of the Western Cape and Robin Maritz, Research fellow, Biodiversity and Conservation Biology, University of the Western Cape

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Why we’re working to put Africa’s jellyfish on the map



New Chrysaora from the coast of South Africa.
Peter Southwood

Verena Ras, University of the Western Cape

Jellyfish can be found in almost every ocean in the world. These beautiful, graceful creatures are a sight to behold; their swift, pulsating motions gently propel them through the water. But the scene can quickly turn ominous as the animal transforms into a ferocious, formidable predator.

These creatures have no special organs for respiration or excretion. They have no head, no brain, no skeleton and no true circulatory system. This allows them to be highly adaptable and to survive in even the harshest conditions.

Most species typically have a multi-phase life cycle. Many jellyfish can exist as polyps on the sea floor, able to create identical clones of themselves. When conditions are just right, polyps are able to release numerous juvenile jellies into the water. Many polyps may even lie dormant when conditions are not favourable, emerging again when they improve. The free-swimming adult jellyfish often eat a variety of marine species from tiny shrimp to small pelagic fish. Many even eat other jellies. The adult jelly can also shrink when food is not available to conserve energy and resources, growing back to its normal size when food becomes available again. This unique life history gives them many advantages over other species.

Jellyfish are also well known for forming large swarms known as “blooms” – which can have far reaching negative effects. Jellyfish blooms have clogged the cooling intakes of power plants, resulting in total shutdowns; they can destroy fishing nets and spoil catches. Many species also deliver a painful sting that many beach-goers may know well.

But despite some of these negative impacts, jellyfish are incredibly useful. They are indicators of oceanic circulation patterns, play a rather large role in the mixing of oceanic nutrients and also help control pelagic fish populations (those that inhabit the water column, not near the bottom or the shore). It was recently discovered that jellyfish even provide microhabitats where other marine species may live and survive.

Jellyfish have also recently become the focus of a number of biotechnology and pharmaceutical studies as they appear to possess many properties that may be useful in a variety of applications, from household cleaning products to fertilisers. Other species are now commercially farmed for human consumption, with large fisheries already established in countries like India and China. Jellyfish are being turned into products like dehydrated chips, protein shakes and other food stuffs.

However, with few dedicated research efforts, jellyfish remain unexplored in many oceans and it is likely that many species have gone unrecorded or unnoticed. Some scientists even suggest that their numbers may be declining in some parts of the world. Global longterm data simply doesn’t exist for jellyfish, so scientists struggle to predict, track and mitigate their potential effects – good and bad.

But collecting the necessary data requires significant resources, manpower and expertise. That’s where a South African-led team of researchers based at the University of the Western Cape’s Department of Biodiversity and Conservation Biology comes in. Using samples collected by a global research vessel, we’ve been able to begin to establish a baseline of data for African jellyfish species. This, we hope, will allow us to establish more thorough trends across oceans, uncover new species (we’ve already identified one) and better understand the links between different species.

Examining the specimens

In 2016, we approached the Food and Agriculture Organisation’s EAF-NANSEN Programme to see whether jellyfish samples could be collected by its Dr Fridtjof Nansen research vessel. EAF-NANSEN agreed, and started collecting samples in waters across the African continent.

The first specimens arrived at UWC late in 2017 and we got to work. Jellyfish have few identifying features and a highly variable body type. So figuring out which species we had in the lab was no easy task. The team typically measures anywhere from 35 to 70 morphological features for any given species, which are then analysed statistically for patterns. DNA is also extracted from various individuals and populations to help identify species and to establish patterns of gene flow across populations.

So, what have we learned? First, it became clear early on that the African coastline encompasses a larger variety of species than previously thought. Our group has already found a new compass jelly off the southern coast of South Africa, along with a new species of rhizostome jellyfish that appears to be completely endemic to South Africa through some of our previous research.

University of the Western Cape masters student Roxy Zunckel swims with the jellyfish Rhizostoma luteum.
Supplied

Second, the team has begun to identify a number of other African morphotypes that appear to be distinct from their global counterparts. The species found here appear to show high levels of endemism, meaning they are changing in their physical appearance and even their DNA to adapt to our waters.

The work is continuing and we have already received three years’ worth of specimens and associated data which we hope to analyse alongside other African jelly experts.

Future plans

The aim of this work is to build up and establish high quality resources for African jellyfish species that may be used to contribute to global studies and reviews. Eventually, we hope to establish population patterns across the east and west African coastlines; at the moment these data simply don’t exist. This will require a coordinated global effort, but as we’ve shown through our collaboration with the NANSEN programme, this is possible and it’s yielding great results.The Conversation

Verena Ras, PhD candidate, University of the Western Cape

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Gabon’s large trees store huge amounts of carbon. What must be done to protect them



Ivanov Gleb/Shutterstock

John Poulsen, Duke University

Large trees are the living, breathing giants that tower over tropical forests, providing habitat and food for countless animals, insects and other plants. Could these giants also be the key to slowing climate change?

The Earth’s climate is changing rapidly due to the buildup of greenhouse gases, like carbon dioxide, in the atmosphere as a result of human activities. Trees absorb carbon from the air and store it in their trunks, branches, and roots. In general, the larger the tree, the more carbon it stores.

Globally, tropical forests remove a staggering 15% of carbon dioxide emissions that humans produce. Africa’s tropical forests – the second largest block of rainforest in the world – have a large role to play in slowing climate change.

But large trees are in trouble everywhere. I carried out research to examine the distribution, drivers and threats to large trees in Gabon. Gabon has 87% forest cover and is the second most forested country in the world.

By carrying out this project, I was able to identify areas with a wealth of large trees (and therefore key carbon stores and sinks), what needed to be done to better protect them and eventually recommend those areas as a priority for conservation.

National inventory

In 2012, the government of Gabon began a national inventory of its forests to measure the amount of carbon stored in its trees – one of the first nationwide efforts in the tropics.

An inventory of this scale isn’t easy, especially in a heavily forested country. Technicians from Gabon’s National Parks Agency travelled to every corner of the country, sometimes hiking more than two days crossing swamps and traversing rivers, to measure the diameter and height of trees in plots a bit larger in size than a soccer field.

Using Gabon’s new inventory of 104 plots, we calculated the amount of carbon in 67,466 trees, representing at least 578 different species. We did this by applying equations to the tree measurements.

The results indicated that the density of carbon stored in Gabon’s trees is among the highest in the world. On average, Gabon’s old growth forests harbour more carbon per area than old growth forests in Amazonia and Asia.

Most of this carbon is stored in the largest trees – those with diameters bigger than 70cm at 1.3 meters from the ground. Just the largest 5% of trees stored 50% of the forest carbon. In other words, 3,373 trees out of the 67,466 measured trees contained half of the carbon.

Drivers of forest carbon stocks

Next, we examined the drivers of carbon stocks. What determines whether an area of forest holds many large trees and lots of carbon? Do environmental conditions or human activities have the largest impact on forest carbon stocks?

Environmental factors – such as soil fertility and depth, temperature, precipitation, slope and elevation – often influence the amount of carbon in a forest. During photosynthesis, trees harness energy from the sun to convert water, carbon dioxide, and minerals into carbohydrates for growth. Therefore, forests with low levels of soil minerals or that receive little rainfall should store less carbon than areas with abundant minerals and water.

Human activities – like agriculture and logging – also influence carbon stocks. Cutting down trees for timber, to clear land for farming, or for construction reduces the amount of carbon stored in forests.

We examined the amount of carbon in each tree plot in relation to the environmental factors and human activities associated with the plot. Surprisingly, we found that human activities, not environmental factors, overwhelmingly affect carbon stocks.

The impact of human activities on forest carbon was largely unexpected because of Gabon’s high forest cover (the second highest of any country) and low population density (9 people per square kilometer), 87% of which is located in urban areas. If human impacts are this strong in Gabon, what must their effects be in other tropical nations?

Although we don’t know for sure, we believe past and present swidden (slash-and-burn) agriculture is the principle cause for low carbon stocks in some areas. Forests close to villages had lower levels of carbon, probably because forest clearing for farming converts old growth forest to secondary forest.

Interestingly, forests in logging concessions held similar amounts of carbon as old growth forests. It is too early to conclude that timber harvest doesn’t reduce carbon levels by cutting large trees, but this finding gives hope that logging concessions can be managed sustainably to conserve carbon stocks.

Importantly, forests in national parks stored roughly 25% more carbon than forests outside of parks. Thus, protecting mostly undisturbed forests can effectively conserve carbon and biodiversity.

Saving Gabon’s giants

The critical role of humans in diminishing carbon stocks is both a blessing and a curse. One one hand, the future of forests are in our hands, giving us the power to choose our fate. On the other hand, we cannot ignore the responsibility to act collectively to secure these resources while considering the interests of the countries that host them.

Gabon is taking laudable actions to conserve its forests, including a protected area network of 13 parks. In addition, Gabon is reforming its logging sector and developing a nationwide land use plan. These actions are a great start, yet continued action is necessary to curb the effects of swidden agriculture and ensure that growing industrial agriculture does not reverse Gabon’s achievements.

Intact forests can pay returns. Norway recently committed to paying Gabon $150 million for stewardship of its forests. Conservation of forests requires sacrifice by the Gabonese people. Yet, this payment demonstrates that Gabon’s large trees are a national asset that can contribute to its development as well as an international resource requiring collective action to conserve.The Conversation

John Poulsen, Associate Professor of Tropical Ecology, Duke University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Getting closer to a much better count of Africa’s lions



A young lion cub rests in the branches of a large euphorbia tree in Uganda’s Queen Elizabeth Conservation Area.
Alex Braczkowski, Author provided

Alexander Richard Braczkowski, Griffith University; Duan Biggs, Griffith University; James R. Allan, University of Amsterdam, and Martine Maron, The University of Queensland

African lions are one of the world’s favourite animals. But their numbers have been shrinking over the past century, especially over the past 30 years. Some scientists estimate that their numbers have halved since 1994.

Estimates of the total population of Africa’s king of beasts vary, but a recent CITES report suggested that only about 25,000 remain in the wild, across 102 populations in Africa. But the numbers in this report aren’t particularly reliable. Most used traditional survey approaches – like counts of lion footprints, audio lure surveys or expert opinion – and many were not peer-reviewed.

These traditional methods of counting lions produce highly uncertain estimates. A count of lions using their footprints may give you an estimate of, say, 50 lions in an area. But the uncertainty around this estimate could be between 15 and 100 individuals. This large uncertainty makes tracking how lion populations change from year to year nearly impossible. Our recent review shows that the majority of methods used to count African and Asiatic lions use these less robust methods.

Two young lions rest in the branches of a Euphorbia tree on the Kasenyi Plains of Queen Elizabeth National Park.
Alex Braczkowski

Making sure that lion numbers are accurate and reasonably precise is key for the species’ conservation. Estimates of lion numbers underpin their classification as ‘vulnerable’. They also form the backbone for controversial management practices like the setting of trophy hunting quotas.

The good news is that better ways of counting lions are being developed. So called spatially explicit capture-recapture methods are useful for conservation because they tell us not only how many animals live in an area, but how they move in a landscape, what their sex ratios are and even where their highest numbers are located. This method has been used to count tigers, leopards, jaguars and mountain lions for over a decade but it is only now becoming popular for lions.

A review of 169 peer-reviewed scientific articles (Web of Science and Google Scholar) showed many lion abundance and density estimates rely on traditional methods like audio lure or track surveys.

Spatially explicit capture-recapture methods use a mathematical model which incorporates the individual identity of animals (usually from photographs of natural body markings, spot patterns or even whisker spots) and their location in a landscape. By identifying and “marking” individuals over a period of time an estimate can be made of the total number of animals that live in an area.

Better methods from East Africa

This method was first used to count lions in a 2014 study in Kenya’s Maasai Mara. The lead authors capitalised on a historic way of identifying lions: their whiskers. Every lion in the wild has a unique whisker spot pattern, very much like a human fingerprint.

Recently, some of us applied this technique in a count of African lions in southwestern Uganda, in a region known as the Queen Elizabeth Conservation Area. These lions are interesting because they have a rare culture of tree-climbing. This means they have great local tourism value as each lion raises about USD$ 14 000 annually in park fees.

The status of lions in Uganda was not previously very well understood. After a wave of intense poaching during the unstable Idi Amin and Milton Obote regimes – 1971 to 1985 – during which time wildlife numbers plummeted.

But recent aerial surveys and radio-collaring studies suggested that lion prey numbers were recovering. A radio collaring study of lions from 2006 to 2010 also showed that lion home range sizes were small, and because range size is predicted by abundant prey, this suggested lions here were in good health.

Uganda’s lions in peril

From October 2017 to February 2018 we drove more than 8 000 km in 93 days searching for lions in the Queen Elizabeth Conservation Area. We obtained 165 lion detections. Using individual identifications from photos, we calculated that on average one could expect to find about 3 individual lions per 100 square kilometres, with a total of 71 lions in the entire area.

Scientists during a census of the lions in Uganda’s Queen Elizabeth Conservation Area.
Steve Winter

We used the spatially explicit capture-recapture method to assess how lion movements had changed from the home range study performed a decade earlier. Worryingly, our results showed that lions had increased their ranges significantly in just 10 years – above 400% for male lions and above 100% for females.

Also, there was only one female for every male in the wild. This is very different to other African lion populations which have a much higher proportion of females relative to males (about two females for every male).

Next steps

From the standpoint of lion conservation and recovery these results are concerning. But, on a positive note, this finding has provided a timely alert. And we recommend the use of this relatively novel survey methodology to assess other lion populations across Africa.

Four young lion cubs trigger a camera trap set on a waterbuck kill on Queen Elizabeth’s Kasenyi Plains.
Alex Braczkowski

More recently, in 2020, another rigorous study at Lake Nakuru National Park, Kenya, applied this approach and found that this method estimated lion population size to be about a sixth of what was previously thought. The Kenya Wildlife Service, in collaboration with local partners is now using spatially explicit capture-recapture in an ambitious nationwide survey of lions and other large carnivores at all potential strongholds across Kenya.

More broadly, these results further bolster the view that by relying on ad hoc, indirect methods to detect lion population trends, we may end up with misleading answers and fail to direct scarce conservation resources optimally.

We argue that all stakeholders involved in lion conservation across Africa and Asia should use rigorous survey methods to keep track of lion populations. These results should then form appropriate baselines for continent-wide reports on lion abundance, and help inform strategies aimed at their recovery.The Conversation

Alexander Richard Braczkowski, Research Associate, Griffith University; Duan Biggs, Senior Research Fellow Social-Ecological Systems & Resilience, Griffith University; James R. Allan, Postdoctoral research fellow, University of Amsterdam, and Martine Maron, ARC Future Fellow and Professor of Environmental Management, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Hundreds of elephants are mysteriously dying in Botswana – a conservationist explains what we know


Vicky Boult, University of Reading

Worrying news has recently come to light: hundreds of elephants have been found dead in Botswana, and as yet, there is no clear cause of death. But as an expert in elephants and their conservation, I believe we can at least rule out a few possible answers.

Here’s what we do know: the first deaths were reported in March, but significant numbers were only recorded from May onwards. To date, it’s thought that the death toll stands at nearly 400 elephants of both sexes and all ages. Most of the deaths have occurred near the village of Seronga on the northern fringes of the Okavango Delta, a vast swampy inland region that hosts huge wildlife populations. Many of the carcasses have been found near to water.

Of those discovered so far, some lay on their knees and faces (rather than on their side), suggesting sudden death, although there are also reports of elephants looking disoriented and even walking in circles. The tusks of the dead elephants are still in place and, as yet, no other species have died under similar circumstances.

Botswana’s elephant politics

Botswana has long been a stronghold for Africa’s remaining 400,000 elephants, boasting a third of the continent’s population. While elephant numbers have widely declined in recent decades, largely due to poaching, Botswana’s population has grown.

However, this growth has been outpaced by the ever-increasing human population. With more elephants and more people, competition for space has escalated and increasingly, elephants and people find themselves at odds. Some communities see elephants as pests, as they feed on and trample crops, cause damage to infrastructure and threaten the lives of people and livestock. In return, people retaliate by killing and injuring offending elephants.

With large rural communities struggling to coexist with elephants, the issue has become highly politicised. In 2019, in a controversial move, president Mokgweetsi Masisi lifted a ban on the hunting of elephants in Botswana, reasoning that hunting could both reduce their numbers and generate income for struggling rural communities. This, against a backdrop of rising poaching, suggests that times are changing for Botswana’s elephants.

The elephants lived on the fringes of the Okavango Delta, a unique ‘desert wetland’.
evenfh / shutterstock

Speculation

This has sparked speculation about the recent deaths. However, given what we know, we can address some of the rumours.

Firstly, it seems unlikely that poachers are to blame, since the tusks of the dead elephants have not been removed. It’s estimated that illegal black-market ivory trade is responsible for the deaths of 20,000 elephants annually.

The elephants could have been killed by frustrated local people, typically by shooting or spearing. In this case however, the sheer number of dead elephants and the lack of reports of gunshot or spearing wounds, does not support this hypothesis.

Poisoning could be used instead, either by poachers or in retaliation by locals. A few years ago hundreds of elephants in Zimbabwe died after drinking from watering holes laced with cyanide, and the proximity of many of the recent deaths to water has given the idea some foundation.

However, in the event of poisoning, we would expect to see other species dying as well, either because they drank from the same poisoned water source or because they fed on the poisoned carcass of the elephant, and this has not been reported.

A natural cause of death?

If the evidence currently available doesn’t support foul play, that leads us to consider natural causes.

Drought can cause significant deaths. In 2009, a drought killed around 400 elephants in Amboseli, Kenya, a quarter of the local population. But drought tends to kill the very young and old, while the deaths recently reported in Botswana show elephants of all ages are affected. Moreover, rainfall in recent months has been near normal, ruling out the influence of drought.

Mount Kilimanjaro looms over Amboseli National Park.
Graeme Shannon / shutterstock

Perhaps because wildlife disease has gained much attention in light of the COVID-19 pandemic, the remaining possibility that has been widely suggested is disease. While COVID-19 itself is unlikely, elephants, like humans, are affected by a range of diseases.

For instance, over 100 were suspected to have died from an anthrax outbreak in Botswana in 2019. Those elephants that seemed disoriented and to be walking in circles might suggest a disease causing a neurological condition.

Still, the information currently available is inconclusive. The Botswana government has released a statement explaining that investigations are ongoing and that laboratories had been identified to process samples taken from the carcasses of dead elephants.

To avoid further speculation and prevent the deaths of more elephants in their last remaining stronghold, it’s vital that investigations are expedited so that the cause of death can be determined and suitable action taken.The Conversation

Vicky Boult, Postdoctoral Researcher in Conservation Biology, University of Reading

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Camera traps completed one of the most thorough surveys of African rainforest yet



PNS Survey, Author provided

Mattia Bessone, Liverpool John Moores University and Barbara Fruth, Liverpool John Moores University

Tropical rainforests are the world’s richest land habitats for biodiversity, harbouring stunning numbers of plant and animal species. The Amazon and the Congo basins, together with Asian rainforests, represent only 6% of Earth’s land surface, and yet more than 50% of global biodiversity can be found under their shade.

But observing even the most conspicuous species, such as elephants and apes, is still an extraordinarily difficult task. That’s not even mentioning all the secretive species that are protected by thick vegetation or darkness.

Camera traps have led a technological revolution in wildlife research, making it possible to study species without humans needing to be present. They can be left in the depths of a forest for weeks, taking pictures of anything that moves at any time of day or night.

Installing camera traps in Salonga National Park.
Jonas Abana Eriksson/PNS Survey, Author provided

From their advent three decades ago, camera traps have allowed scientists to discover species such as the grey-faced sengi – a new species of giant elephant shrew living in Tanzania – and the Annamite striped rabbit in Vietnam. They revealed that lions still wander the Bateke plateau in Gabon, ending speculation that they were locally extinct. They also photographed the offspring of the elusive Javan rhino, which scientists had thought had stopped breeding. With fewer than 100 individuals left, this gave hope that the species could be saved from extinction.

The grey-faced sengi (Rhynchocyon udzungwensis) was discovered by camera traps in Tanzania.
F Rovero/Wikipedia, CC BY-SA

Spotting stripes

Camera traps are becoming essential for documenting forest species, assessing their distribution and studying their behaviour, as well as counting what’s actually there.

This latter measure, called animal abundance, is perhaps the most important information in wildlife conservation, as it allows researchers to assess the conservation status of a species. But until recently, camera traps could only be used to reliably estimate the abundance of animals with conspicuous markings, such as big cats with spots or stripes peculiar to single individuals.

Big cats, like this African leopard (Panthera pardus), are among the simplest species to document with camera traps.
Haplochromis/Wikipedia, CC BY-SA

Counting animals with camera traps remained impossible for the majority of species that lacked these conspicuous features, as the same individual could be counted twice by different cameras at different times. Methods that account for how animals move in and use their habitat were developed to help overcome the problem of detecting the same individual at different locations.

Another method, called camera trap distance sampling achieves the same result using a different approach. It subdivides the time cameras are active into “snapshots”, taking pictures at, for example, every fifth second in an hour. At a determined moment, an individual can only be spotted at one location, not elsewhere. Double counts are avoided, and researchers get the number of animals within the area surveyed by the cameras at a given snapshot.

We tested this new method in one of the most remote areas of the planet – the southern part of Salonga National Park, a world heritage site in the Democratic Republic of the Congo. Here, rangers only had data on the park’s two flagship species – the forest elephant and the bonobo. Near to nothing was known about the other animals that were more difficult to track.

A flagship species of Salonga National Park, bonobo populations are understudied in 70% of their range.
Christian Ziegler/LKBP, Author provided

What we found

Five field teams walked a forest the size of Wales to deploy 160 camera traps in 743 places. This unprecedented effort produced more than 16,000 video clips, totalling 170 hours of animal footage and revealing 43 different animal species, including bonobos and elephants.

We also captured species rarely detected by human observers, such as the giant ground pangolin, threatened by extinction, the cusimanses, a genus of social mongooses, and the stunning Congo peafowl, a vulnerable species that’s endemic to the country.

Where so far conservation of elusive species such as the African golden cat, the endemic Allen’s swamp monkey and another elephant shrew, the four-toed sengi, had to be based on little to no data, we’re now able to estimate their abundance in the wild.

Nine of 43 species captured by camera traps in Salonga National Park, DRC.
PNS Survey, Author provided

For some species, the news from our findings were good. Our study revealed that the southern part of Salonga National Park alone harboured as many peafowls as were previously thought to be present in the whole country.

For other species, the results confirmed the need for greater protection. The 17,000 km² large and intact primary rain forest contains fewer than 1,000 giant pangolins. An alarming figure given the current illegal trade of pangolin scales.

As the technology and methods of camera trap surveys improve, they’re becoming capable of monitoring a diverse range of wildlife, from the tiny elephant shrew to the mighty forest elephant. This gives an insight into the complex and delicate equilibrium of the rainforest community and the threats to its survival.The Conversation

Mattia Bessone, PhD Researcher in Conservation Biology, Liverpool John Moores University and Barbara Fruth, Associate Professor, Liverpool John Moores University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Lemurs are the world’s most endangered mammals, but planting trees can help save them



Black-and-white ruffed lemurs are important indicators of rainforest health.
Franck Rabenahy, CC BY-ND

Andrea L. Baden, Hunter College

Madagascar, the world’s fourth-largest island, is a global biodiversity hotspot.
Andrea Baden

The island of Madagascar off the southeastern coast of Africa hosts at least 12,000 plant species and 700 vertebrate species, 80% to 90% of which are found nowhere else on Earth.

Isolated for the last 88 million years and covering an area approximately the size of the northeastern United States, Madagascar is one of the world’s hottest biodiversity hotspots. Its island-wide species diversity is striking, but its tropical forest biodiversity is truly exceptional.

Sadly, human activities are ravaging tropical forests worldwide. Habitat fragmentation, over-harvesting of wood and other forest products, over-hunting, invasive species, pollution and climate change are depleting many of these forests’ native species.

Among these threats, climate change receives special attention because of its global reach. But in my research, I have found that in Madagascar it is not the dominant reason for species decline, although of course it’s an important long-term factor.

As a primatologist and lemur specialist, I study how human pressures affect Madagascar’s highly diverse and endemic signature species. In two recent studies, colleagues and I have found that in particular, the ruffed lemur – an important seed disperser and indicator of rainforest health – is being disproportionately impacted by human activities. Importantly, habitat loss is driving ruffed lemurs’ distributions and genetic health. These findings will be key to helping save them.

Deforestation from slash-and-burn agriculture in the peripheral zones of Ranomafana National Park, Madagascar.
Nina Beeby/Ranomafana Ruffed Lemur Project, CC BY-ND

The forest is disappearing

Madagascar has lost nearly half (44%) of its forests within the last 60 years, largely due to slash-and-burn agriculture – known locally as “tavy” – and charcoal production. Habitat loss and fragmentation runs throughout Madagascar’s history, and the rates of change are staggering.

This destruction threatens Madagascar’s biodiversity and its human population. Nearly 50% of the country’s remaining forest is now located within 300 feet (100 meters) of an unforested area. Deforestation, illegal hunting and collection for the pet trade are pushing many species toward the brink of extinction.

In fact, the International Union for Conservation of Nature estimates that 95% of Madagascar’s lemurs are now threatened, making them the world’s most endangered mammals. Pressure on Madagascar’s biodiversity has significantly increased over the last decade.

A red ruffed lemur, one of two Varecia species endemic to Madagascar.
Varecia Garbutt, CC BY-ND

Deforestation threatens ruffed lemur survival

In a newly published study, climate scientist Toni Lyn Morelli, species distribution expert Adam Smith and I worked with 19 other researchers to study how deforestation and climate change will affect two critically endangered ruffed lemur species over the next century. Using combinations of different deforestation and climate change scenarios, we estimate that suitable rainforest habitat could be reduced by as much as 93%.

If left unchecked, deforestation alone could effectively eliminate ruffed lemurs’ entire eastern rainforest habitat and with it, the animals themselves. In sum, for these lemurs the effects of forest loss will outpace climate change.

But we also found that if current protected areas lose no more forest, climate change and deforestation outside of parks will reduce suitable habitat by only 62%. This means that maintaining and enhancing the integrity of protected areas will be essential for saving Madagascar’s rainforest habitats.

Warm colors indicate areas where lemurs can move about readily, which promotes genetic diversity; cool colors indicate areas where they are more constrained and less able to mate with members of other population groups.
Baden et al. (2019), Nature Scientific Reports, CC BY-ND

In a study published in November 2019, my colleagues and I showed that ruffed lemurs depend on habitat cover to survive. We investigated natural and human-caused impediments that prevent the lemurs from spreading across their range, and tracked the movement of their genes as they ranged between habitats and reproduced. This movement, known as gene flow, is important for maintaining genetic variability within populations, allowing lemurs to adapt to their ever-changing environments.

Based on this analysis, we parsed out which landscape variables – including rivers, elevation, roads, habitat quality and human population density – best explained gene flow in ruffed lemurs. We found that human activity was the best predictor of ruffed lemurs’ population structure and gene flow. Deforestation alongside human communities was the most significant barrier.

Taken together, these and other lines of evidence show that deforestation poses an imminent threat to conservation on Madagascar. Based on our projections, habitat loss is a more immediate threat to lemurs than climate change, at least in the immediate future.

In 1961 naturalist David Attenborough filmed ruffed lemurs for the BBC.

This matters not only for lemurs, but also for other plants and animals in the areas where lemurs are found. The same is true at the global level: More than one-third (about 36.5%) of Earth’s plant species are exceedingly rare and disproportionately affected by human use of land. Regions where the most rare species live are experiencing higher levels of human impact.

Crisis can drive conservation

Scientists have warned that the fate of Madagascar’s rich natural heritage hangs in the balance. Results from our work suggest that strengthening protected areas and reforestation efforts will help to mitigate this devastation while environmentalists work toward long-term solutions for curbing the runaway greenhouse gas emissions that drive climate change.

A young woman participates in reforestation efforts in Kianjavato, Madagascar.
Brittani Robertson/Madagascar Biodiversity Partnership, CC BY-ND

Already, nonprofits are working hard toward these goals. A partnership between Dr. Edward E. Louis Jr., founder of Madagascar Biodiversity Partnership and director of Conservation Genetics at Omaha’s Henry Doorly Zoo, and the Arbor Day Foundation’s Plant Madagascar project has replanted nearly 3 million trees throughout Kianjavato, one region identified by our study. Members of Centre ValBio’s reforestation team – a nonprofit based just outside of Ranomafana National Park that facilitates our ruffed lemur research – are following suit.

At an international conference in Nairobi earlier this year, Madagascar’s president, Andry Rajoelina, promised to reforest 40,000 hectares (99,000 acres) every year for the next five years – the equivalent of 75,000 football fields. This commitment, while encouraging, unfortunately lacks a coherent implementation plan.

Our projections highlight areas of habitat persistence, as well as areas where ruffed lemurs could experience near-complete habitat loss or genetic isolation in the not-so-distant future. Lemurs are an effective indicator of total non-primate community richness in Madagascar, which is another way of saying that protecting lemurs will protect biodiversity. Our results can help pinpoint where to start.

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Andrea L. Baden, Assistant Professor of Anthropology, Hunter College

This article is republished from The Conversation under a Creative Commons license. Read the original article.