Sunday, July 13, 2014

Palm Oil Problems

Fruit from which palm oil is produced
Palm oil is an ingredient in countless household items ranging from cosmetics to food items to biofuels. It's become a huge conservation issue because the majority of palm oil plantations come from Indonesia and Malaysia, where forests have been cut down to put up these plantations, causing massive habit loss for animals such as orangutans, rhinos, sun bears, leopards, other species of monkeys, and many more animals. Deforestation has resulted in forests that are increasingly fragmented, making it harder for animals to find potential mates, to disperse, and making it difficult for those species requiring large home ranges to survive. Additionally, all of this cutting has resulted in increased greenhouse gases, contributing to global warming.

The demand for this popular vegetable oil is growing. Already 40-50% of the items found in homes in the US and one out of every ten items in supermarkets in the UK contain palm oil.

A recently published study (July 10) in the journal Current Biology report the need to prevent these large plantations from spreading to Africa. The article states that of the area deemed suitable for palm oil plantations, 42.3% of that area overlaps with the African great apes (chimpanzees, bonobos, and gorillas). Almost 40% of the distribution of great apes in Africa on unprotected land overlaps with areas considered suitable for palm oil plantations.  The authors determined that palm oil plantations will pose a significant threat to apes in Africa. In some countries, areas suitable for growing this crop overlap with ape habitat by as much as 80%.

Palm oil plantation
So what do the authors suggest to prevent palm oil companies from extending their reach even further into Africa? Public awareness of the environmental and social impacts (such as issues with water quality  and poor working conditions) this industry creates. Most people have never heard of palm oil, which can also be labeled as palmate, vegetable oil, Elaeis guineensis, etc. They have no idea of the destruction it causes to forests across the world. So what can we do to help? Be informed, tell your friends, and reduce your usage of palm oil as much as possible. It's very difficult to do, as palm oil truly is in so many products, but that doesn't mean we shouldn't try.

Food for thought: Apes have a very long life cycle. For example, orangutan offspring remain with their mothers until on average eight years old and won't give birth themselves until around age 15. When they do give birth, it's to a single offspring. How does this long life history work against them when it comes to conservation efforts? Think about population numbers.

Tuesday, July 8, 2014

General Bat Biology

One of the best parts of Piro Biological Station is that it is a true research station with multiple people from across the world coming to do their research in the Osa. A few weeks ago, bat researcher Melquisedec Gamba-Rios, a PhD student at the University of Tennessee-Knoxville, gave an introductory talk on the biology of bats. Melqui is at Piro for three months gathering data for his dissertation and I learned a lot from his talk.

Of the over 5200 species of mammals on this planet, bats make up 1200 of those species (21% of all mammals). They are the second largest group of mammals after rodents. Costa Rica alone is home to 117 species of bats.

Bats aren't blind, but they can't see very well at night. During the day, though, they see just fine. At night, they rely on echolocation, which you've probably heard of. Bats produce ultrasounds as they move and they need to keep moving so that they can send these sounds in different directions. They use their ears, of course, but bats also use their nose lip to "see" differences in textures.  They can move this nose lip to give direction to the sound they're sending out. They change the frequency of the sound they're sending out depending on their location. For example, bats will send out a flatter signal in an open area than in a forested one.

Bats roost in caves typically in the United States but they can also use holes in trees. Some bats in the tropics specialize in roosting in fallen trees over creeks or rivers. They have a social system with the alpha male roosting on top. Very uncommon are bats that roost on leaves in the tropics. There are bats that will make a tent-like structure out of large leaves by biting through the leaf to make a roost. Of the 112 bat species in Costa Rica, 17 modify leaves in some way.
Styloctenium wallacei roosting in tree

I was particularly interested in learning what Melqui had to say about the diet and feeding ecology of bats. Most bats are insectivores, consuming insects, but some species consume fruit, nectar, or even fish or small birds. One bat can consume 700-1000 mosquitos per hour. Fruit-eating bats are important seed dispersers, as bats will consume the juice of the fruit but spit out seeds, meaning these seeds remain intact and can grow away from their original tree. There are three species of bats that fish and two of those species live in Costa Rica (Noctilio leporinus and Noctilio albiventris) . They echolocate off of the water and can consume five to six tiny fish per night. These bats have adaptations to help them fish such as large feet and claws to snatch their prey out of the water. The echolocation these bats send when over the water is so loud that the bats will actually close their ears when they are directly over the sounds.

Of course, Melqui had to devote part of his talk to vampire bats, or bats that use their incisors (not their canines) to feed off of the blood of other animals. There are three species of vampire bats and they are all found in Costa Rica. An anticoagulant is in their saliva so that they can consume more of another animal's blood without it clotting. Vampire bats drink two teaspoons of blood per night and, if they don't eat for two or three nights, they die. To prevent death, bats can detect when another bat needs blood and can give it to them. However, this type of help only happens between family groups. Vampire bats will actually land close to their prey and then walk up to the animal so as not to startle it. Their nose is specifically shaped to detect hot areas of skin where blood is. And, while yes, bats can carry rabies, there are more problems in the United States with raccoons and rabies than with bats.

To learn more about bats, I recommend the following website: Bat Conservation International.

Food for thought: Why would vampire bats only help members of their own family? (Think about evolution and an individual's fitness, or ability to survive and produce viable offspring, thus contributing to the gene pool of future generations.)

Wednesday, July 2, 2014

The four species of primates found at Piro

Four species of primates can be seen at Piro Biological Station in Costa Rica. Squirrel monkeys (Saimiri oerstedii oerstedii), spider monkeys (Ateles geoffroyi), white-faced capuchins (Cebus capucinus), and howler monkeys (Alouatta palliata) are all monitored by the station with a focus on spider monkeys as indicators of overall forest health.  White-faced capuchins and mantled howler monkeys are both classified by the International Union for Conservation of Nature and Natural Resources as of least concern. Population trends for both of these species are unknown. Spider monkeys are classified as endangered, with population numbers decreasing and squirrel monkeys are currently classified as vulnerable with their numbers decreasing as well.
White-faced capuchin feeding

How do these four species exist in the same forest without conflict? Well, sometimes there is conflict, but these species differ in some ways. For example their diet and use of the forest is not identical, allowing each species to live together.

Howler monkeys predominantly consume leaves. They even regularly include mature leaves as a part of their diet, which is uncommon due to the high fiber content of mature leaves and relatively low abundance of readily accessible calories. Leaves aren't generally a desirable food item in tropical forests. Just think about fighting over lettuce: not a food item you'd fight over at the grocery store for. That said, you don't see howler monkeys fighting over leaves.

Spider monkeys specialize in the upper parts of the forest, including emergent trees and the upper canopy. They usually travel and forage high in the trees. Spider monkeys are frugivorous, preferring to consume ripe fruits if possible. Over 80% of their diet is composed of fruits. Spider monkeys consume fruit in the emergent level of the forest, where other primates may rarely visit, if ever. Ripe fruits are a desirable food item (I'm guessing you're likely to fight over a juicy peach than a piece of spinach), but spider monkeys are relatively large primates and, from what I saw, they typically dominate the other primate groups they encounter. Spider monkeys can also consume non-fruit items when needed/available, such as immature leaves, flowers, seeds, and even small insects.

Squirrel monkeys are also frugivorous but insects also compose a decent portion of their diet. These monkeys can use all levels of the forest but are mainly found in the lower canopy and understory, thus not overlapping with spider monkeys. They also seem to prefer secondary forest and river edge forests. When fruit is less abundant during the dry season, they increasingly depend on insects and other animal prey.
Squirrel monkey

Finally, capuchins occur in many types of forests (mangrove, dry deciduous, humid subtropical forests along with forests that have been degraded). Like squirrel monkeys, they can also be considered frugivores and insectivores. Their diverse diet includes fruits, seeds, flowers, frogs, and even small mammals. These intelligent monkeys, arguably the most intelligent monkey of Central and South America, are extractive foragers, meaning they can manipulate their environment to obtain foods that are embedded, sometimes using tools to obtain these food items. Examples of capuchin extractive foraging include pounding seed pods against the ground to open them, using sticks to probe for insects, and using specifically shaped rocks to crack open palm nuts.

How these four species of primates interact is not entirely understood. There is still much to be learned about interspecific competition, or competition between different species for the same resources, in Costa Rican primates.

To read more about these primates at Piro click here.