A diamond in the marsh: Saving the Lake Alaotra Gentle Lemur

This article was commissioned by mongabay.com, and the original can be found here: http://news.mongabay.com/2015/08/a-diamond-in-the-marsh-saving-the-lake-alaotra-gentle-lemur/

Climb into a canoe at dawn, paddle into the reed beds of Madagascar’s largest wetland, and with luck you could see a unique primate: the Alaotra Gentle Lemur (Hapalemur alaotrensis). Known locally as the bandro and described by Gerald Durrell as a “honey-coloured teddy bear”, these lemurs spend their entire lives within the cyperus and reed stems of the marsh around Lake Alaotra in Eastern Madagascar.

“What really fascinates me [is] that this lemur species is the only primate that lives constantly on water,” Patrick Waeber, of Madagascar Wildlife Conservation (MWC) told mongabay.com. Waeber, also a lecturer at ETH Zurich, knows the species better than most, first studying their social behavior in 2000. “It was during over 160 sampling hours that I initially came to know this compelling lemur species intimately.”

The bandro is the largest of the gentle lemurs, weighing a little over 2.5

The Alaotra Gentle Lemur is the only primate that lives exclusively within a wetland habitat. Photo credit Toby Nowlan.

The Alaotra Gentle Lemur is the only primate that lives exclusively within a wetland habitat. Photo credit Toby Nowlan.

pounds. Their dense fur grows grey on face, chest, and ears; a rich brown on head and back. A long tail helps with balance on the floating vegetation of the marsh. The animals live in small territorial family groups, and, as is typical of many lemurs, females are dominant.

People pressure driving decline

With their range extending to just 20,000 hectares (49,421 acres), their population declining, and habitat highly threatened, the species has been classified as Critically Endangered by the International Union for Conservation of Nature (IUCN). Their unique ecology and threatened status have also earned them a place on the EDGE (Evolutionarily Distinct and Globally Endangered) mammal list, a program run by the Zoological Society of London that “highlights and conserves one-of-a-kind species that are on the verge of extinction.”

“We currently estimate between 2,000 to 2,500 Bandro,” Lance Woolaver told mongabay.com. He is the head of Species Conservation and Research at the Durrell Wildlife Conservation Trust (Durrell) Madagascar. Durrell initiated some of the first studies of the bandro in the early 1990s.

“Research showed it was endangered and completely dependent on the remaining marsh,” Woolaver said. Back then, the population was estimated to be 11,000 – they have declined by almost 80 percent – and hunting for bushmeat was their greatest direct threat. In an attempt to curb hunting, Durrell reached out to the local people, holding environmental festivals to “engage local communities, discuss the importance of the marshes and demonstrate the uniqueness of the lemur to Alaotra.” This outreach was successful, with habitat loss and fragmentation – which isolates groups of bandro – now overtaking hunting as the biggest problem facing the species.

Jonah Ratsimbazafy, Secretary General of GERP (the Madagascar Primate Group) started working to conserve the bandro in 2003, and still remembers his first encounter of the bandro in the wild. “The first individual/group we saw… for me, was like discovering a diamond,” Ratsimbazafy told mongabay.com.

A young Alaotra Gentle Lemur. Photo credit: Arnaud De Grave.

A young Alaotra Gentle Lemur. Photo credit: Arnaud De Grave.

Ratsimbazafy also serves as the co-vice chair of the IUCN/SSC Primate Specialist Group for Madagascar, which has identified Alaotra as one of 33 priority sites for lemur conservation. He explained what drives habitat loss today: “People convert the marsh into rice field, but before doing that, they burn the marsh…. and certainly many bandro are caught in the fire.”

The marshes are burned not only to make way for rice fields, but also to improve access to fishing grounds, which are suffering from invasive plant species encroachment. “A major threat to the marsh and lake comes from an exponential increase in the number of people relying on the lake for fishing,” Woolaver said. Erosion in the lake’s headwaters is also a problem. “The lake’s long-term future depends on managing the surrounding hillsides which, due to deforestation, pour silt into the lake.”

The Alaotra wetland is at the heart of Madagascar’s “rice bowl” region, which produces a third of the national rice harvest. The lake is also a nationally important freshwater fishery. “The Alaotra was once the biggest inland fish supplier, but these stocks are now imperiled,” Waeber explained. In a country of extreme poverty these natural resources are vital in the deepest sense of the word. But exploiting them has a major impact on Alaotra’s biodiversity.

Two of the world’s rarest mammals

Alaotra’s ecological importance is not limited to the bandro. Numerous rare and endemic species inhabit the wetland, including Meller’s Duck (Endangered), and the endemic Madagascar Rainbowfish (Vulnerable). Others have already vanished, such as the Madagascar Pochard (Critically Endangered) and the Alaotra Grebe, which was declared extinct in 2010.

But even as these species struggle for survival, startling new discoveries are being made. In 2004 researchers realized that an aquatic, mongoose-like mammal observed swimming in the marshes was unknown to science. Formally described in the same year that the Alaotra Grebe’s extinction was confirmed, Durrell’s Vontsira (Salanoia durrelli) was the first new species of carnivorous mammal to be discovered in 24 years. And that’s not all. “There is also an undescribed species of mouse lemur probably unique to the marshes of Alaotra,” Woolaver said.

A live-trapped Durrell's Vontsira just after release. Photo credit BioCensus.

A live-trapped Durrell’s Vontsira just after release. Photo credit BioCensus.

So far, little is known about the cat-sized Durrell’s Vontsira. It has physical adaptations to its aquatic habitat such as enlarged paws, which distinguish it from its forest-dwelling relative, the Brown-tailed Mongoose (Salanoia concolor). Knowledge of its population – estimated at fewer than 465 individuals – and its behavior is gradually accumulating thanks to weekly marsh patrols established by Durrell to monitor the bandro, the Vontsira, and illegal activities. “Camera-trapping and live-trapping have also been trialed and work well with this species,” Woolaver added.

With such low population densities, seeing either the bandro or the Vontsira in the dense marsh grasses requires a great deal of luck. What are the chances, then, of witnessing an interaction between two of the rarest mammals in the world?

“I was lucky to encounter a Salanoia [Vontsira] with one of my bandro groups back in 2000,” Waeber recalls. “The group consisted of three adults and two juveniles. The Salanoia was targeting the little ones. The adults shushed them up a cyperus to be out of reach by the carnivore. At the same time, the three adults surrounded the attacker and charged it continuously. After some minutes, annoyed by the continuous attacks, the carnivore gave up and went off.”

The global significance of Alaotra’s biodiversity was recognized in 2003, when the entire 722,500 hectare (2,790 square mile) watershed was designated a Ramsar site – recognized under the Ramsar Convention, an international wetland preservation treaty. In 2007, with the help of Durrell and other NGOs, the region was afforded further protection by the creation of a community-managed New Protected Area.

“Despite these protective designations, burning for conversion to agricultural land-use (i.e., rice production) is steadily and rapidly reducing the amount of potential lemur habitat,” Waeber said. About 6 percent of marsh habitat is lost every year.

“Marshes can recover from burning,” Waeber continued, but “because the frequency and number of fires are increasing, the chances of proper recovery of the marshes is decreasing.”

Community based management

Finding a way to balance people’s needs with the conservation of biodiversity is the key conundrum facing organizations working in the region. “Alaotra is one of Durrell’s core conservation zones in Madagascar, and the challenges there really exemplify the issues faced by conservation projects in Madagascar,” Woolaver said. “A major conservation challenge is to ensure secure livelihoods for these local communities that want to sustainably manage the lake and marshlands.”

Durrell's Vontsira, formally described in 2010, was the first new carnivorous mammal to be discovered in 24 years. Photo credit Lance Woolaver.

Durrell’s Vontsira, formally described in 2010, was the first new carnivorous mammal to be discovered in 24 years. Photo credit Lance Woolaver.

Durrell’s early efforts to engage local communities provided the foundation for community-based management of the marshes. Durrell was instrumental in the establishment of 28 community associations which now manage 90 percent of the 23,000 hectares (56,834 acres) of marsh that remain.

A pioneering participatory ecological monitoring project was also developed, which provided communities with improved education, food security and access to clean water. “This program collected distribution data on biodiversity, and also improved relationships with local communities and encouraged them to protect the marsh,” Woolaver said.

More recently, Durrell has been providing capacity-building support for the establishment of the New Protected Area. “We want to make sure that the New Protected Area becomes a tool for sustainable management of the marsh and lake, by local communities themselves,” Woolaver explained. Durrell’s other priorities include making sure the boundaries of the protected area are clear, with “rebuilding of law enforcement and the trust between local communities and authorities” and “continuing to work with local communities to ensure good fishing management, and improved agriculture yields.”

Alaotra Gentle Lemur. Photo credit: Alice Smith.

Alaotra Gentle Lemur. Photo credit: Alice Smith.

“In order to do this we do need significant levels of engagement and long-term financial support from major development organizations and donors,” Woolaver said.

GERP, the Madagascar Primate Group, also focuses on supporting people who rely on the wetland for their livelihood. “We work with the local communities in the form of collaboration, but not dependence,” Ratsimbazafy emphasized. “We know that their involvement to the success of the project is crucial, so we provide training in farming/handcraft techniques, good governance, patrol activities, and monitoring of bandro and the habitats, for instance.”

Weekly patrols monitor endangered species and illegal activity in Alaotra. Photo credit: Durrell.

Weekly patrols monitor endangered species and illegal activity in Alaotra. Photo credit: Durrell.

Eco-tourism and conservation training come to Alaotra

On the eastern shore of the lake, near the town of Andreba, lies Parc Bandro, a protected area of 80 hectares (198 acres) managed by MWC. “With the consent of the community, we have built Camp Bandro to allow visitors to stay overnight, [and] to be at the lake and in the marshes by sunrise. This is the prime time for lemur watching,” Waeber explained.

A night at the Camp, followed by a dawn canoe excursion in search of the Parc’s roughly 170 bandro, will set you back just under $7. “The underpinning idea is to show the Andreba community the link between conservation… and the increased numbers of tourists.”

Unfortunately, as Waeber acknowledges, the logistical difficulties of reaching the area mean that few tourists make the journey. “Tourism in Madagascar works fine for only less than a handful of national parks which generate the majority of revenue…. [A]t Camp Bandro, we have had in the past years on average between 50 to 80 tourists.”

MWC has also been looking to the future. Training the next generation of Malagasy conservationists is a priority. Working in collaboration with both Durrell and GERP, MWC will enable 10 Malagasy students to undertake Master’s research on the bandro’s ecology and conservation.

Celebrating World Environment Day in Alaotra. Photo credit: Durrell.

Celebrating World Environment Day in Alaotra. Photo credit: Durrell.

An environmental education program aimed at primary school children and teachers has also been developed, with 3,000 comic books entitled Arovy fa harena (Protect because it’s worth it) distributed to schools so far. “The children experiencing environmental education are clearly more aware of the lake biodiversity,” Waeber said.

A cooperative solution to preservation

Increasing engagement with local communities is crucial, but they alone will not determine the fate of the Alaotra. Much of the destruction of the marsh is driven by people outside the region.

“Lack of law enforcement has led to land-grabbing by powerful people, most of whom are not even from the local communities around Alaotra,” Woolaver explained.

“That is why we try to find ways to empower the local communities,” Ratsimbazafy said. Furthermore, he thinks the law should be applied equally to all.

“In a complex socio-ecological system such as the Alaotra, conservation needs to engage with a multitude of actors,” Waeber contends. “We also need to bring our conservation efforts to the attention of the actors of change; the policy and decision makers.”

Reeds in the Alaotra marshes, habitat for the Alaotra Gentle Lemur and Durrell's Vontsira. Photo credit: Lance Woolaver.

Reeds in the Alaotra marshes, habitat for the Alaotra Gentle Lemur and Durrell’s Vontsira. Photo credit: Lance Woolaver.

To this end, Waeber and Madagascan collaborators have launched the AlaReLa (Alaotra Resilience Landscape) project, to help resource users and decision-makers “find a balance between conservation and development, and thereby improve the adaptive capacity of Alaotra‘s social-ecological landscape.”

When it comes to the outlook for Alaotra’s people and biodiversity, there is optimism. But secure livelihoods, financial support, and political will are all needed for the region to thrive. “As long as the people depending on the marshland system are struggling to make a living, the ecosystem is at high risk to reach a point of no return,” Waeber warned. “Bridging cultural, ecological and agricultural values and needs will be key to conserving the bandro and other species such asSalanoia durrelli.”

“The two species can be saved from extinction, it isn’t too late by any means,” Woolaver concluded. “All of the knowledge, experience and techniques have been developed and are there to save the bandro and Vontsira, but a major concentrated and integrated effort requiring financial support will be required.” And if these flagship species can be saved, the rest of Alaotra’s biodiversity can be saved alongside them.

Alaotra Gentle Lemurs are threatened by the loss of their wetland habitat as it is burned to make way for rice fields. Photo credit Toby Nowlan.

Alaotra Gentle Lemurs are threatened by the loss of their wetland habitat as it is burned to make way for rice fields. Photo credit Toby Nowlan.

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The evolution of cooperation: communal nests are best for ruffed lemurs

I wrote this article for mongabay.com where it was first published; you can read it here.

Raising young lemurs in communal crèches benefits both mothers and offspring, a new study has found. Andrea Baden and colleagues, of Yale University, studied a group of black-and-white ruffed lemurs (Varecia variegata) in Ranomafana National Park, Madagascar. This is the first study to examine the consequences of different parenting strategies in the ruffed lemur. By observing how mothers split their time between different activities, they discovered that crèche use – where infant care was shared between mothers – corresponded with an increase in the amount of time a mother spent feeding. For young lemurs, being raised in communal nests actually gave them a higher chance of survival.

Dr Andrea Baden with a black-and-white ruffed lemur.

Black-and-white ruffed lemurs are large-bodied social primates that live in the eastern rainforests of Madagascar, and have an almost entirely fruit-based diet. Reproduction is synchronized, and in this study seven females gave birth during a two week period. Unlike many primate species, young are born undeveloped, even unable to cling to their mothers’ backs, so they must be cared for in nests until they are big enough to travel independently.

The study, published in Behavioral Ecology and Sociobiology, found that females built a number of nests during the gestation period, with some building as many as fifteen. Females gave birth to litters of 2-3 young, and for the first few weeks of life infants were cared for solely by their mothers. Communal nesting, typically involving two litters sharing a nest, began when the young lemurs were six weeks old. Six of the seven mothers nested communally at least once, although the amount of time their young spent in crèches varied. Two of the mothers only rarely or never shared nests. But females who shared nests were able to spend significantly more time feeding than those that did not participate in communal nesting, and time feeding and foraging increased with increasing crèche use. All infants survived until the start of the communal nesting period, but infant mortality was subsequently significantly higher for single nesters than communal ones.

Behavioral observations were combined with genetic data which made it possible to work out whether it was only related lemurs that were assisting each other. The study found that although relatedness and long-term social relationships were positively correlated with the extent of communal nest use, “not all cooperative dyads [two individuals] were related, and not all related dyads cooperated with each other.” The benefits of communal nesting were the same regardless of whether the lemurs were related to each other.

“Kinship may have helped the evolution of cooperative breeding in primates but the mutual benefits may outweigh the costs of helping, irrespective of any family relationships” says Baden, who believes that the current research sheds light on understanding just how communal breeding evolved. “Our results contribute to a growing body of evidence suggesting that kin selection alone cannot explain the extensive cooperation observed in many animal taxa.”

In six years of study, only one reproductive event was observed. Such rare and unpredictable reproduction makes research a challenge. The scientists point out that, despite a relatively small sample size, their study “nonetheless represents reproductive output over 48 lemur-years”. The timing of reproduction is not fully understood, but it is likely that the lemurs respond to environmental cues.

“In 2008, Cyclone Ivan hit. More than 2,000 [millimeters] of rain fell over the course of three days. It’s possible that this somehow signaled the likelihood of a highly productive fruiting year”, Baden told mongabay.com.

Black-and-white ruffed lemurs are classified as Critically Endangered by the IUCN, having suffered a decline of 80% over the last 27 years. Baden fears that their fruit-dependent diet and sporadic reproduction will make them even more at risk in the future. Ruffed lemurs are “among the first animals to disappear when habitats become disturbed or degraded, as large fruiting trees are typically targeted during selective logging” Baden explains. “My concern is that climate change and the erratic climatic variations that come with it might have severe and significant repercussions for ruffed lemur life histories.”

Female black-and-white ruffed lemur feeding.  Photo by Andrea Baden.

Female black-and-white ruffed lemur feeding. Photo by Andrea Baden.

One of the most surprising aspects of the results for Baden was the extent to which female behavior changed during the breeding period. “It really seems like infants are driving sociality in this species. In non-reproductive years, females were almost asocial.”

“It’s fascinating” Baden added, “by having a litter of three infants and then communally rearing those babies, females can essentially make up for two lost years of reproduction. These animals have really perfected their parenting system to adapt to these reproductive lags.”

Baden feels that lemurs are frequently overlooked in discussions of primate social evolution. “Ruffed lemurs are really interesting because they actually share several traits – things like fission-fusion social dynamics and cooperative infant care – with higher primate species that many would consider to be quite socially complex” Baden said. “I think we’re starting to learn that, while lemurs perhaps differ from higher primates in several of their ‘solutions’ to evolutionary problems, they have come up with some really interesting and unusual adaptations that can still inform our broader understanding of primate evolution.”

Data collection in the field. Photo by Andrea Baden.

Data collection in the field. Photo by Andrea Baden.

Infant black-and-white ruffed lemur. Photo by Andrea Baden.

Infant black-and-white ruffed lemur. Photo by Andrea Baden.

Reference: Baden A.L., Wright, P.C., Louis E.L., Bradley B.J. (2013). Communal nesting, kinship, and maternal success in a social primate, Behavioral Ecology and Sociobiology. DOI 10.1007/s00265-013-1601-y