Lemur Conservation is about Vanilla, and that’s not bland
By Logan Hamilton
Chances are that the vanilla you find in your ice cream comes from Madagascar- nearly 80% of the world’s vanilla gets produced there. Madagascar is also home to the lemurs- a group of primates that live only on Madagascar. At least, they do for now- wild habitats across the globe are being lost to human activities, and Madagascar is no exception. In fact, nearly all species of lemur are at risk of extinction thanks to habitat loss, hunting for bushmeat, and the pet trade.
But there is a silver lining- maybe it’s better to call it a vanilla lining, since vanilla plantations in Madagascar provide hope for these adorable primates. A study by Hending and colleagues showed that some lemurs can be found in vanilla plantations, suggesting that these croplands may be used in future conservation management.
Types of Plantations
The vanilla plant is like a baby bird. Baby songbirds learn to sing by listening to an older bird, a tutor, which allows them to hear what a correct song sounds like. Vanilla also needs a tutor: it is an orchid that survives by living on sturdy “tutor” plants like trees. Without tutors, vanilla crops would be weak, so having sturdier limbs on a vanilla plantation is important for crop survival. However, there are a few different ways to “hire” such tutors.
Intensive plantations are the most disturbed vanilla locale, with tracts of forest cut down and replaced with the grower’s choice of vanilla tutors- which does not always include the local plants. An ecoplantation is a more traditional method that involves growing vanilla on tutors that were already there. These ecoplantations can be divided into two groups: nonforest plantations that are more than 100 meters (about the length of a football field) away from a forest fragment without vanilla, and forest plantations that are less than 100 meters from such fragments.
The researchers searched for lemurs by following transects- long straight lines through a study site- on each of these three types of plantations (intensive, forest, and nonforest). They also looked for lemurs in areas of natural habitat near plantations as a comparison against the vanilla locations. As they walked each transect, the researchers counted the number and species of the lemurs they saw.
Lemur Sighted!
What luck! They found lemurs using the plantations! And not just one, but five different species! Four were nocturnal- they were mostly active at night, like owls. The fifth species, the endangered Crowned Lemur, was also the most common lemur observed, and they saw as many as 11 lemurs on a single transect! Even better, the lemurs they saw were either eating or resting, which suggests that they were comfortable in the plantation tutors. The researchers found more lemur species in the natural habitat transects, but those in the plantations overlapped with those in natural habitat- except one. The nocturnal Greater Dwarf Lemur was only found on vanilla plantations.
Most plantation lemurs were found on forest ecoplantations, suggesting that more intact forests- even if vanilla is being grown in part of them- are more attractive to wild lemurs. But lemurs were also found on the more disturbed intensive plantations, suggesting they may be hardier than they’ve been given credit for.
Vanilla as a Habitat Corridor
Imagine a hallway with lots of doors, each leading to a different room. The rooms are all of different sizes, the distances between them vary, and they have different types of food available. Getting between the rooms is easy- you just walk down the hallway to your next destination. Now imagine that the hallway no longer exists. How do you get between the rooms? You could crawl out the window and climb your way over, but what if your destination is really far and you don’t have the strength to make it? You could climb up to the roof and travel there from above, but you’re more exposed to the elements and have a chance of falling and dying. This isn’t so easy or safe without the hallway, is it?
You’ve just pictured forest fragmentation. When habitats get destroyed, they are not always removed in one fell swoop. Instead, small pockets- fragments, or the rooms in our imagined scenario- get left by themselves. Animals like lemurs cannot move between these fragments very easily, and if they try to make the journey they could die on the way. This leaves the animals in each fragment effectively isolated from those in the other fragments.
In order for a species to survive, conservation managers want populations of that species to be connected. Forest fragmentation does the opposite. Conservation efforts then hope to counter fragmentation, but how do we connect these isolated fragments? Why not a hallway? It’s relatively safe, and it makes the journey easier. Such wild hallways are referred to as “habitat corridors”, and they have been shown to help connect fragmented populations.
In Madagascar, forests are increasingly fragmented as people cut them down to make room for agriculture. But now, Hending and colleagues have shown that lemurs will use vanilla plantations. This means that these plantations- especially forest plantations- could serve as corridors.
There is one factor, however, that at first glance could throw a kink in this plan. Do lemurs eat vanilla? According to Hending and colleagues, they do not; the lemurs observed in their study were found feeding from the plantation tutors rather than from the vanilla crop. In most cases, tutor plants are not part of a farmer’s crop, and so lemurs feeding on those tutors are not considered pests.
This solution seems like a win-win: vanilla plantations can provide local communities with sustainable income, and fragmented lemur habitats can be linked by plantations that can be established with minimal impacts on the local environment, especially if those plantations are of the forest ecoplantation type. In other words, vanilla plantations may be a key strategy for lemur conservation. How could that be bland?
Works Cited
Hending, Dan, et al. “The Use of Vanilla Plantations by Lemurs: Encouraging Findings for Both Lemur Conservation and Sustainable Agroforestry in the Sava Region, Northeast Madagascar.” International Journal of Primatology, vol. 39, no. 1, Feb. 2018, pp. 141–153., doi:10.1007/s10764–018–0022–1.
