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.

Caught on camera: The fossa, Madagascar’s elusive top predator



File 20180918 158237 1o9612m.jpg?ixlib=rb 1.1
Fossa (Cryptoprocta ferox) at the Houston Zoo.
Josh Henderson, CC BY-SA

Asia Murphy, Pennsylvania State University

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.

An alert fossa looks out over the rainforest.

Madagascar’s top carnivore

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.

Two male fossa captured on camera in northeastern Madagascar.
Asia Murphy

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.

Tracking fossa with cameras

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.

Flat Tail, seen in 2008 as a young pup (left) and 2013 as a mature male (right). We were able to follow this fossa as he grew up thanks to his strange and unique tail tip.
Asia Murphy & Zach Farris

The value of a number

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.The Conversation

Asia Murphy, PhD candidate, Pennsylvania State University

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

The endangered species list: counting lemurs in Madagascar


File 20180723 189335 1t5uopy.jpg?ixlib=rb 1.1
The endangered Coquerel’s Sifaka lemur.
Shutterstock/Monika Hrdinova

Ian Colquhoun, Western University

Most people are familiar with the endangered species list. Officially known as the IUCN Red List of threatened species, it’s coordinated by the International Union for the Conservation of Nature (IUCN) and provides the most up-to-date indication of the health of the world’s plants, animals and fungi to guide critical conservation action.

Examples include reports on declining leopard populations and improving mountain gorilla numbers. The list also signals when a species hasn’t been sighted in decades, is feared extinct, or has been “rediscovered” – as was the case for the large-billed reed-warbler.

To date, more than 91 000 species have been assessed for The IUCN red list. But, how is the list constructed and who is involved?

It’s a surprisingly complex process, involving the combined efforts of literally thousands of researchers. These “specialist group” volunteers use their expertise and time to create and maintain a central database which monitors the conservation statuses of the planet’s species. For mammals alone, there are 37 specialist groups.

My own involvement in contributing to the list has been through the Madagascar section of the IUCN Primate Specialist Group. This group involves approximately 450 primatologists worldwide. We are organised into specialist sections according to the biological classification of primate groups, such as the great apes, or regional areas of primate occurrence like South America or Africa. The Madagascar section of the group includes about 90 researchers who specialise in the study of lemur species.

Cyclical evaluation

Every five years the various specialist groups undertake reevaluations of the conservation statuses of the species on which they focus. This is currently being carried out for all 113 known lemur species by our section.

The last conservation assessment, conducted back in 2012, led to the alarming conclusion that lemurs are the most endangered group of mammals on the planet – 94% of all lemur species were classified as either “endangered” or “critically endangered”. A lot can change in five years. Since then, new lemur species have been described and there’s been a wealth of new field study data gathered on known lemur species. All this feeds into the current lemur conservation status reassessments.

The basis of the cyclical process is information that the IUCN specialist groups gather from researchers and their field studies. The researchers can either be university based, NGO’s or privately funded ones. The field data are assessed according to an extensive set of evaluative quantitative criteria, including: population size; the risk of continuing decline in total population size; and the degree to which the species under consideration now exist in small and relatively isolated subpopulations, as these subpopulations are at a greater risk of going locally extinct.

Species were broadly categorised as “endangered”, “vulnerable”, “rare”, “indeterminate”, or “other”. But, since the mid-1990s, a quantitatively-based conservation status assessment process has instead been adopted. This developed out of internal review of the species conservation assessment process. The current assessment practice places a premium on using up-to-date quantitative field data to the greatest extent possible. Species are now classified as either: “data deficient”, least concern”, or as falling into one of the “threatened” categories, “vulnerable”, “endangered”, or “critically endangered”.

It’s not unusual that for a given species the desired quantitative data are simply not available or known. In such cases, the IUCN still encourages that:

the absence of high-quality data should not deter attempts at applying the criteria, as methods involving estimation, inference and projection are emphasised as being acceptable…

This is where the role of research experts really comes to the fore. Researchers who have conducted recent field studies can provide relatively up-to-date insight on situations regarding species, even though these data may not yet be published. For many species groups, including lemurs, it’s a relatively short list of researchers who fit that bill.

So, to some extent, it’s a case of either using on-the-ground knowledge of the species or site knowledge of those experienced researchers, or attempt to arrive at conservation assessments without their expert input. But it also depends on who is in the room when the assessments are made.

Important lists

This reliance on expert input, while recognised as being of key importance, has also recently come under criticism for not also employing evidence or proper process in making decisions.

But, because swift conservation action is seen as crucial to the overall process, the central role of expert researchers in determining the conservation statuses of species will continue in the future.

The IUCN Red List is not the only endangered species list out there. For example in the primate world, the International Primatological Society produces a biennial review report with the IUCN looking at the 25 most endangered primates.

The ConversationThe next one will be released after the Congress of the International Primatological Society in Nairobi. It will show how important these lists are to raise public consciousness of the threats that primates face, and the conservation efforts used to address them.

Ian Colquhoun, Associate Professor of Anthropology, Western University

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