For time immemorial, many wildlife species have survived by undertaking heroic long-distance migrations. But many of these great migrations are collapsing right before our eyes.
Perhaps the biggest peril to migrations is so common that we often fail to notice them: fences. Australia has the longest fences on Earth. The 5,600-kilometre “Dingo Fence” separates southeastern Australia from the rest of the country, whereas the “Rabbit-Proof Fence” stretches for almost 3,300 kilometres across Western Australia.
Both of these enormous fences were intended to repel rabbits and other “vermin” such emus, kangaroos and dingoes that were considered threats to crops or livestock. Built over a century ago, their environmental impacts were poorly understood or disregarded at the time.
Since construction these fences have caused recurring ecosystem catastrophes, such as mass die-offs of emus and other species trying to find food and water in a land notorious for the unpredictability of its rainfall, vegetation growth and fruit production.
The same thing is happening across much of the planet. While a nemesis for larger wildlife, nobody knows how many fences exist today or where they’re located. A study that mapped all the fences in southern Alberta, Canada, found there were 16 times more fences than paved roads.
Scientists are waking up to the peril of fences, realising that from an environmental perspective they’re grossly understudied — “largely overlooked and essentially invisible,” according to a recent global review.
In Africa, home to some of the most spectacular wildlife migrations, scientists found that of 14 large-mammal species known to migrate en masse, five migrations were already extinct. Proliferating fences, along with habitat loss and wildlife poaching, has sent ecosystems such as the Greater Mara in Kenya crashing into ecological turmoil.
And a 2009 audit of Earth’s greatest terrestrial-mammal movements showed that of 24 large species that once migrated in their hundreds to thousands, six migrations have vanished entirely.
Many remaining migrations are mere shards of their former glory. For instance, Indochina once had mass migrations of elephants and other large mammals, big cats, monkeys and birds — often called the “Serengeti of Southeast Asia”.
The thundering herds of American bison – some numbering up to 4 million animals – which once dominated the plains of North America have all but vanished today.
There are two main ways to destroy mass migrations: killing the animals outright by hunting and over-harvesting, or stopping the animals from accessing food or water, typically by fencing them out or clearing and fragmenting their habitat.
As the human footprint rapidly expands, scary things for wildlife are happening all over. Research that one of us (Bill Laurance) led revealed that 33 African “development corridors” would, if completed, exceed 50,000 kilometres in length and crisscross the continent, chopping its ecosystems into scores of smaller pieces.
Beyond this, over 2,000 parks and protected areas in Africa would be degraded or cut apart by the massive developments.
Migrations are vulnerable even in the seas. Recent research shows that growing shipping traffic is an increasing danger to migratory great whales, basking sharks, and giant whale-sharks – all highly vulnerable to collisions with fast-moving ships, as well as disruption of their sensitive hearing and vocal communications by shipping noise and sonar, and pollutants from vessels.
But the inspiring news is that, if you remove barriers such as fences, animal migrations can spontaneously resume – like a phoenix rising from the ashes.
In 2004, a fence that had blocked a former zebra migration in Botswana was removed. By 2007 it was one of the longest animal-migration routes in the world.
And a few places on Earth are still free from fencing and fragmentation. The world-famous Seregeti ecosystem of Tanzania is an iconic example. In war-torn South Sudan, a spectacular mass migration of a million antelope — known as white-eared kob — is still intact because there are no fences.
And caribou still migrate in great herds across large expanses of northern Canada and Alaska.
Collapsing migrations are a global concern, but right now conservationists are most worried about Botswana.
This mega-diverse nation in southern Africa is considering profoundly changing its wildlife management by expanding fences and cutting off wildlife migrations not considered beneficial to the country’s current priorities.
This would be a shocking decision, because Botswana’s wildlife conservation is almost entirely dependent on its mass migrations.
For wildebeest, zebra, eland, impala, kob, hartebeest, springbok and many other large migrants, isolation is a killer – destroying their capacity to track the shifting patterns of greening vegetation and water availability they need to survive.
And it’s not just grazing and browsing animals that are affected: entire suites of large and small predators, scavengers, commensal and migratory bird species, grazing-adapted plants and other species are integrally tied to these great migrations.
Botswana is already sliced into 17 giant “islands” by fences, erected in colonial times to protect the livestock of European farmers from foot-and-mouth disease.
But foot-and-mouth disease is far more likely to be spread by cattle, not wildlife. Fence-free strategies for managing disease risk also have have great potential.
And nature tourism in Botswana is a large, vibrant, and growing part of the national economy. Ecotourists will continue to favour the nation so long as it maintains untrammelled areas and spectacular animal migrations.
But you can kiss a lot of those tourism revenues goodbye if Botswana shatters its great migrations – killing off the spectacular living panoramas that are a magnet for the world’s nature lovers.
If we can avoid fencing and bulldozing critical parts of the Earth, we could hugely increase the chances that our most vibrant wildlife and ecosystems have a fighting chance to survive.
Bill Laurance, Distinguished Research Professor and Australian Laureate, James Cook University and Penny van Oosterzee, Adjunct Associate Professor James Cook University and University Fellow Charles Darwin University, James Cook University
The link below is to an article that takes a look at the threats to Botswana’s elephants from poaching.
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.
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.
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.
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.
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.
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.
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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Mention wildlife on Madagascar and the first thing listeners probably picture is the island’s famed lemurs. As many people know, these unique primates are found nowhere else, and are the most endangered group of mammals in the world. But few people realize that lemurs’ fate is directly bound up with that of Madagascar’s largest predator, the fossa (Cryptoprocta ferox), which is threatened by some of the same pressures.
Fossa are terrier-sized, cat-like relatives of mongoose with tails as long as their bodies. Like other top predators such as lions and wolves, they play a critical ecological role regulating the populations of their prey.
Like much of Madagascar’s wildlife, fossa are found nowhere else in the world. But scientists know little else about them, including how many fossa there are. They are rare, difficult to see in the wild, and lack unique coat patterns that would make it easy to distinguish individual animals.
I worked on a team of researchers from the United States and Madagascar that spent seven years surveying Madagascar’s largest protected area – a zone the size of Connecticut – with trail cameras to see if we could determine how many fossa were there. We found that this area holds a significant portion of the global fossa population, and is likely the last stronghold for this unique species. Our research provides key information that can help correctly assess fossas’ threatened status and lay the basis for appropriate conservation action.
Fossa weigh about 20 pounds and can prey on most of Madagascar’s other species. They are capable hunters on land and in the trees, using their tails for balance and killing by biting through their prey’s skulls. One study found that fossa were largely responsible for two lemur family groups disappearing from forests over a two-year period. Fossa, like other top predators, help keep prey populations at a level that their habitat can support, and rid the population of diseased and weak individuals.
Fossa also exhibit some very interesting behaviors. They are one of nine mammalian species whose sexually immature females go through a period of transient masculinization. During this phase, their clitorises enlarge and grow spines to look like an adult male fossa’s penis. Researchers think this helps sexually immature females avoid the aggressive attentions of males looking for females with which to mate.
In the deciduous forests of western Madagascar, scientists have discovered that male and female fossa will gather together at the same spot year after year to mate. Otherwise, however, fossa were thought to be solitary until 2010, when researchers observed three male fossa working together to kill a lemur. Since then, some male fossa have been seen to team up with another male or two to hunt prey and protect a larger territory than solitary males. And in 2015, our study captured photos suggesting that male fossa in the eastern rainforests will also associate.
Lack of funding and political instability has made it hard for Madagascar’s government and conservation organizations to study the fossa. Because of their elusive nature, it is particularly hard to figure out basic things, such as how many fossa there are in an area. And without good numbers, scientists can’t assess whether a species is threatened or develop plans for protecting it.
Automatic cameras, known as camera traps, are a standard tool for collecting information on elusive wildlife in remote areas. The only thing “trapped” is the animal’s digital image.
Our images showed what type of habitat fossa used, when they were active, and how they co-existed with other carnivores such as dogs. Variations among individual animals, such as scars, tail width and kinkiness, and the presence and number of ear nicks, made it possible to start picking out certain fossa from the population and “follow” them from one camera to another.
One of our top goals was assessing how many fossa were present in the reserve and how close together they were. Determining density is key for conserving species. Once we knew know how many fossa there were, on average, in a unit of area such as square kilometer, we could estimate how many there were in the entire region and compare between different protected areas.
Over a seven-year period we ran 15 surveys across seven study sites in the reserve. For months on end, we set up cameras, checked them, downloaded data and then moved cameras to survey as much area as possible. In all of this time, I never personally saw a fossa, but two local field assistants saw fossa in the trees once or twice.
Next came three years of analyzing photos, recording which animals had identifying marks and how far those marked fossa moved during their daily activities. Finally, nearly a decade after the very first survey in Masoala-Makira, we had a population estimate.
We calculated the fossa population in Masoala-Makira at 1,061, give or take around 500 animals. This worked out to about 20 fossa per 100 square kilometers. In other words, we had a small town of lemur-eating carnivores living in an area the size of Connecticut.
Why is this important? Because our colleague Brian Gerber did a similar study in southeastern Madagascar, with one important difference: He applied his estimate to the area of all of Madagascar’s protected forests. He estimated there to be 8,626 fossa in the entire world.
Only two protected areas were large enough to hold enough fossa that the population could stay stable, at the very least, despite individuals dying or being killed. We showed that Masoala-Makira is one of them. And as the largest protected area in Madagascar, it will be home to fossa long after they disappear elsewhere due to hunting and habitat loss.
The next priority is to survey Madagascar’s other protected area large enough to hold a self-sustaining population, the Zahamena-Mantadia-Vohidrazana complex, to better estimate the global fossa population. And local governments need to attempt to curb hunting within protected areas and control feral dogs and cats, which can kill native species and spread diseases.
Rare and charismatic species typically get the most conservation attention, especially through events like National Geographic’s Big Cat Week. In fact, however, there are four times more lions than fossa in the entire world. Maybe it’s time for Fossa Friday.
Africa’s wild lion population is estimated to be between 20 000 and 30 000. Researchers have good reason to believe that the real number is closer to 20 000. This puts lions in the “vulnerable” category of threatened species.
The categorisation masks important realities. The only growing populations are those in fenced reserves with small wild managed populations. This is not only a species crisis. It’s also an ecological and economic crisis. Lions are apex predators, which means that entire food chains and ecological systems depend on healthy populations. Lions are also a significant tourism drawcard, and tourism is a significant employer.
South Africa, uniquely, also allows the breeding of lions in captivity, most of which have no conservation value. It has an estimated 7000 to 8000 lions in captivity across roughly 300 facilities. These lions are predominantly bred for canned hunting and the Asian predator bone market.
A report prepared by by EMS, an activist charity, and the lobby group Ban Animal Trading, shows that lion bones are sold on the black market as tiger bones. The bones are dropped into rice wine vats and sold as tiger bone wine which is promoted in Asian markets as a treatment for rheumatism and impotence. The bones are also used to produce tiger bone cakes, an exotic small bar of melted bones mixed with additives like turtle shell.
The report argues that most lion bones come from captive-bred lions in South Africa.
Captive breeding is perfectly legal, if distasteful. But there are limits on the trade of lion bones. In 2016 the 17th CITES Conference of the Parties decided that no bone exports should be allowed from wild lions. But the conference also agreed that South Africa should establish a quota for skeleton exports from captive-bred lions. Captive breeding only occurs at scale in South Africa, so no other country is permitted to export lion bones.
A year later the Department of Environmental Affairs set an annual lion skeleton export quota at 800. It raised this to 1500 in July 2018. It did so without public consultation or the support of research. Even an interim report prepared for the department by the South African National Biodiversity Institute did not specify grounds on which to establish, or expand, a quota.
On top of this, there’s poor regulation of lion breeding facilities. The department doesn’t have a working database so doesn’t know how many facilities there are, or what the total number of captive-bred predators is.
In my new report, I discuss how breeding facilities are linked to the trade in lion bones.
The facilities arrange hunts that cost in the region of $22 000 for a male and female combination. Wildlife researcher, Karl Amman, describes how trophy taxidermists then sell the lion skeletons (without the skull) on to buyers. These are usually in Asian countries. A skeleton can fetch $1500.
The importer then sells the bones on for between $700 and $800 per kg. A 100kg lion yields about 18kgs of bone, worth roughly $15 000 at this point in the supply chain. The bones are then imported into Vietnam, boiled down in large pots to yield 100g bars of cake which are sold for roughly $1000.
Conservationists are concerned that South Africa’s quota provides an incentive to breed lions not only for the bullet, but also for the bone trade.
The 2017 quota was fully subscribed within weeks while a newly released report prepared for CITES suggests that 3469 skeletons were exported that year, nearly double the allocated number.
This rise in the trade of lion bones shouldn’t come as a surprise. In 2016 the US banned the import of captive-origin lion trophies from South Africa. Breeding facilities began looking for alternative markets. Selling lion carcasses was an obvious option given that a lioness skeleton fetches roughly R30 000, and a male skeleton about R50 000, when sold to a trader.
The predator breeding industry in South Africa argues that captive lion populations serve as a buffer against wild lion poaching because it can satisfy the demand for bones.
But those who oppose the trade in lion bones cite evidence that suggests the opposite is true. If anything, the quota could fuel the demand for lion products and provide a laundering channel for illegally sourced wild lion parts. This may imperil already vulnerable wild lion populations elsewhere in Africa. It also makes law enforcement extremely challenging: officials cannot be expected to distinguish between legal and illegally sourced bone stock.
The public outcry over an apparently arbitrary quota has been notable. The backlash against canned hunting and the bone trade has been similarly vocal.
The arguments against the trade have been put on the table at a two-day colloquium in South Africa’s parliament. The question being asked is: does the captive lion breeding industry harm, or promote, South Africa’s conservation image?
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Ultimately, it is parliament’s job to hold the government to account. The colloquium may go some way towards doing so. It may even end the brutality of captive predator breeding.
The global cheetah population is continuing to decline with only about 7000 individuals left in Africa. This is thought to be about half the population that existed 40 years ago. The decline has been caused by the loss and fragmentation of their natural habitats, a decline in their prey base, the illegal trade in wildlife as well as conflict with humans for space.
Cheetahs have disappeared from 91% of their historic range. This is hugely problematic as cheetahs are a wide-ranging species. To be viable a cheetah population needs a contiguous, suitable habitat which covers about 4,000–8,000 km2. But few protected areas in Africa are larger than 4,000 km2.
As a result, most of the cheetahs in the world – 77% – are believed to range outside protected areas. But this isn’t ideal for the animals as, from previous research we conducted using data from GPS satellite collars fitted on cheetahs in the Maasai Mara, we found that cheetahs avoid areas of high human disturbance and prefer protected, wildlife areas.
These results show the importance of wildlife areas for cheetahs, but my most recent research shows that these protected spaces have challenges of their own. We found that the number of cubs a cheetah is able to rear is lower in areas that receive lots of tourists compared with areas that are visited less. This suggests that cheetahs aren’t getting the protection they need, particularly from the impact of growing numbers of tourists.
Famous for its spectacular wildebeest migration, the Maasai Mara is a popular tourist destination. The wildlife areas of the Maasai Mara include the Maasai Mara National Reserve, which is managed by the Narok County Government, and numerous wildlife conservancies, each run by different management companies.
The conservancies are formed through a partnership between Maasai landowners and tourism companies, whereby landowners receive a fixed, monthly payment for leasing their land for wildlife based activities on the condition that they do not live on the land, cultivate or develop it. Combined, the wildlife areas, which are predominantly used for photographic tourism, cover an area of about 2,600 km2 – one-tenth the size of Wales or Belgium.
During the high season about 2,700 people visit the Maasai Mara National Reserve daily. But they are often not adequately managed.
The Mara Reserve – with the exception of a conservancy called the Mara Triangle – doesn’t limit the number of tourists that enter the park per day, and there are no restrictions on the number of tourist vehicles at a predator sighting. It’s therefore not uncommon to see more than 30 tourist vehicles at a sighting.
Ideally, the Mara Reserve should restrict the number of tourists, especially during the peak tourist seasons.
Tourists also affect the landscape of wildlife areas. For example, tourist accommodation is continuing to increase in the Mara Reserve and these facilities are usually built on river banks which are prime habitats for species such as elephants, leopards and breeding raptors.
One crucial element for a healthy cheetah population is cub recruitment, defined as offspring survival to independence.
Cheetahs have relatively big litters, ranging between one to six cubs. But cheetah cubs can succumb to various factors including abandonment, poor health, and fires so the number of cubs that reach independence can be very low, ranging from 5% to 28.9%.
I was interested in finding out if tourism is playing a role in this.
By analysing four years of data on female cheetahs with cubs it became apparent that high numbers of tourists are having a negative effect on the number of cubs that reach independence. More specifically, females in areas with a lot of tourists on average raised one cub (or none survive) per litter to independence compared to more than two cubs in low tourist areas.
There was no hard evidence of direct mortality caused by tourists. But my conclusion from my findings is that tourists are likely to have an indirect effect on cub survival. This could be because they lead to cheetahs changing their behaviour and increase their stress levels by getting too close, overcrowding with too many vehicles, staying at sightings for prolonged periods of time and by making excessive noise.
My study highlights the importance of implementing and enforcing strict wildlife viewing guidelines, especially in areas where tourist numbers are high. The Maasai Mara’s wildlife conservancies are largely getting this right. Tourist numbers are limited to the number of beds per conservancy and only five vehicles are allowed at a sighting at any given time.
Actions that could be taken include:
allowing no more than five vehicles at a cheetah sighting;
ensuring that no tourist vehicles are allowed near a cheetah lair (den);
ensuring that vehicles keep a minimum distance of 30m at a cheetah sighting;
ensuring that noise levels and general disturbance at sightings are kept to a minimum;
ensuring that vehicles do not separate mothers and cubs; and that
cheetahs on a kill are not enclosed by vehicles so that they can’t detect approaching danger.
If tourism is controlled and managed properly, it can play a very positive role in conservation. Money from tourism goes towards the creation and maintenance of protected areas – like the wildlife conservancies – and can help alleviate poverty. It also shows local communities the benefits that predators can bring and can positively influence attitudes.
However if human pressures, like tourism, remain unchecked it risks having a negative impact on wildlife and could mean the loss of some of the biggest attractions – like cheetahs.