Do you have an ecosystem that you have studied that you really love? What's your favorite?
That’s a tough question…. My favorite place to work is on terrestrial forests. Two of my favorite forests are the Blue Ridge forests of temperate Appalachia and the cloud forests of tropical Ecuador. The Appalachians are located along the Eastern United States from northeastern Alabama and Georgia, through eastern Tennessee and western North Carolina, into central Pennsylvania. They are some of the most diverse temperate deciduous forests in the world. The Andean Mountains of Ecuador are located around the equator in South America and are one of the most diverse forests of the world. Plant diveristy can be as high as 300 tree species in one hectare.
Do you think hunting may also have an impact on microbes that live on the animals such that they may find a new host, possibly being transferred to humans?
That’s an interesting question. Hunting does increase the contact between humans and game species, therefore increasing the probability that a microbe may infect humans. Lebreton and colleagues (2006) recently published a research paper in Animal Conservation discussing the importance of bringing awareness to local communities of the risk involved in hunting and butchering animals, especially primates. They discuss some examples of how hunting has been linked to transmitting diseases, such as ebola. Dr. Wolfe is studying how hunting affects the transmission of diseases between animals and humans. To learn more about this topic, you can visit his web page at http://www.wolfelab.com/. If you look under his selected publications, the first one listed in Nature is a review of how human diseases may have arisen from animal diseases.
How do ecosystems work?
An ecosystem is made up of both biotic (living) and abiotic (non-living) parts. Plants absorb energy from the sun to produce sugars and take up nutrients from soil. Plants are eaten by other organisms (herbivores), which are then eaten by still other organisms (carnivores, bugs in the soil, etc.). When an organism dies, decomposers release nutrients into the soil that were previously locked up in the organism . Thus energy and nutrients cycle through the system and get recycled. This is a simplistic description of an ecosystem, leaving out many interactions. Scientists tend to simplify ecosystems because they are easier to understand and study its components. By putting all of these different components together, scientists can understand how ecosystems work. Islands are simplified ecosystems that are easier to study because they are isolated from the mainland, simplifying many of the interactions. A great example of this is Isle Royale in MN where the predator-prey-plant interactions are well-studied. To learn more about Isle Royale, check out http://www.isleroyalewolf.org/. Another island that is intensely studies, is Barro Colorado Island (BCI), which is where I conduct some of my research. For more information about BCI, check out http://www.stri.org/english/research/facilities/terrestrial/barro_colorado/index.php.
What role does the animal life play in the spread of "noxious" organisms, such as green ash borer, gypsy moth and the like. Even if mankind did not transport material, such as wood, would the animal life transport larvae and others so that the spread of these things would have a natural ebb and flow, eliminating certain species for a time, then having only the strong or disease resistant survive?
I am not quite sure what the role of other animals are in spreading noxious organisms. I would expect it’s minimal because few things can travel as far and frequently as we can.
Have you ever been out in the field studying gathering data and something sneaks up on you like a storm or animal
Yes, there are many times that I have been working in the forest and it starts raining and thundering and lightening, especially in the rainy season. The rainy season in Panama lasts from May-December. When I'm in the forest and am near my vehicle or near the field station I try to get back before the thunderstorm starts or becomes more severe.
I have also run into snakes occasionally. In Costa Rica, I have walked by some fer-de-lances. Fer-de-lances are highly venemous snakes found in Central and South America. They are in the family of vipers. While I was working in Australia, I have seen pythons, such as carpet pythons, which can grow up to 5 meters long. In Australia, I was working as a field assistant observing bower birds. (The male birds build these little “bowers”, which are simplified “stages” with two walls and a platform to attract females. The male birds will dance and sing around these bowers for the females). I was walking my trail to observe different bowers, and a koala started walking towards me. I got out of it’s way and it started to walk towards me again. Finally, it passed me by. Here in Panama, I have had peccaries startle me occasionally. I remember once I was counting seeds in my seed traps, and a pack of four with a couple of young peccaries walked right by me. We startled each other and the peccaries ran one way and I the other. I’ve also had white-faced monkeys sneak up on me and throw branches at me and pee on me. Rather unpleasant.
what is the most funnest tropical forest you visited?
The most fun tropical forests I ever visited are in Ecuador. You can see so many different types of habitat within a few days. For example, you can go to the beach one day and a few days later be at 4000 meters (13,000 ft) elevation. Between 3500 and 5000m, there is a type of habitat called the paramo. The paramo has high endemism (species that are restricted to that area). The paramo is made up of wet grasslands and peat bogs with low-growing plants with small, thick leaves adapted to the intense sunlight, cold, and windiness. Below the paramo are cloud forests, which are enveloped in a layer of clouds. With this high moisture, there is a high abundance of epiphytes (plants that grow on other plants but are not parasitic), such as orchids, ferns, bromeliads and mosses.
Another interesting forest I've visited is a dry forest in Costa Rica (Guanacaste National Forest). The rainy season is between May and November. In the dry season, the temperature can get up to 100 degrees Farhenheit. During this time, the majority of the plants tend to lose their leaves to conserve water.
Do reptiles and amphibians spread seeds like mammals, birds, and insects or are they too slimy?
Great question! The dispersal of seeds by reptiles is called saurochory, and there are several examples of this. In the Canary Islands, there is a lizard that disperses an endemic plant that produces berries. In Florida, the Florida box turtle disperses several species of plants and can increase germination of some species. Figs are dispersed by many different animals, including mammals, birds, reptiles, and fish! There is much less known about seed dispersal by amphibians, though one study found salamanders dispersing seeds of Bur-marigold.
Do certain animals affect the tropical forest more than others?
This simple answer is, we don’t know. Animals can affect forests in many different ways. Animals, such as insects and hummingbirds, pollinate plants. Insect and hummingbird pollination is higher in the tropics than temperate areas, where wind pollination is more prevalent. Pollination by animals helps plant species find each other more efficiently in the tropics, where many species are rare. Animals are also important seed dispersers, especially, again, in the tropics. Eighty percent of tropical plant species are dispersed by vertebrates, such as primates and birds. Many plant species are also dispersed by ants and dung beetles, and as I mentioned above, can be dispersed by reptiles, fish, and by an amphibian. There are also many animal herbivores, that eat leaves and seeds. These herbivores include mammals, such as deer, mice, agoutis, peccaries, squirrels, etc., and insects, such as aphids, caterpillars, and bruchid beetles. Bruchid beetles lay their eggs on seeds, when the eggs hatch, the larvae drills its way into the seed, and devours the seeds from the inside out. Mammals, especially large mammals, like tapirs and us!, can also kill very small plants by trampling on them. This can be very important in the spatial structure and diversity of plant communities.
Another important group of organisms that are very important for forest communities are microbes. Fungi, bacteria, and viruses are important in causing plant diseases but also can have positive affects on plants. For example, bacteria called rhizobia help the plant take up nitrogen. Mycorrhizae are a group of fungi that can help plants get nutrients.
My research will hopefully help us understand which of these organisms (vertebrates, fungi, or insects) are relatively more important for seed survival.
What I have described above are examples of how animals can directly affect plant communities. Animals can also have indirect effects on plant communities. An ecologist working here in Panama found that insectivorous birds can decrease herbivory by eating the insects off the plants. These types of interactions are called ‘tritrophic’ because there are three trophic levels (or feeding levels): bird that eats insect that eats plant. Another ecologist in Panama found that Central American spiny rats eat and consequently disperse spores (the reproductive unit) of mycorrhizae, thereby influencing how these mycorrhizae and their plant hosts interact.
Another really cool interaction I forgot to mention earlier is that between ants and several species of plants, such as Cecropia and Acacia plants. These plants offer rewards to ants in the form of food bodies which are a source of sugars for the ants, The ants in return protect the plant from insect herbivory.
if seed removing animals were hunted to extinction, what would be the global impact?
We don’t really know what the long-term consequences of hunting are. The impacts on plant communities depends on what kinds of plants and remaining animals are in a forest. The studies done to date show that hunting tends to decrease seed dispersal and seed predation of plant species with large seeds, but there are a few exceptions. Conversely, hunting can increase seed predation of small-seeded species. This is because smaller mammals, such as mice and rats, may increase in abundance as there is less competition and predation in the absence of the larger mammals. These changes in seed dispersal and seed predation are reflected in changes in the composition of plant communities, or the identity of species that make up the plant community. For example, the identity of saplings, or young plants, are different in a hunted forest than a protected forest. In a hunted forest in Panama, the sapling community is made up of species that are dispersed by wind or bats and species that have large seeds (because their predators are missing). In contrast, the protected forests have a greater proportion of species that are dispersed by mammals and fewer large-seeded species, as these are eaten by agoutis or peccaries. In Peru, the number of species of saplings dispersed by large and medium primates is higher in protected than hunted forests. Other studies have shown that the sapling diversity, or the number of different species, may increase or decrease, depending on the forest.
These changes in plant density, composition, and diversity, can further change interactions with other organisms, such as insects. Bruchid beetles, as I discussed earlier, are important seed predators that are indirectly affected by hunting. Large seeds that are missing their mammal seed predators are more likely to be attacked by bruchid beetles instead.
Very recently, a researcher in Panama found that hunting can even change how plants grow. In the absence of mammal herbivores, seedlings or recently germinated seeds, tend to have thinner leaves than seedlings that are accessible to mammals. Thicker leaves make the leaves harder to eat and therefore helps protect the seedlings from mammals. When there are no mammals, the seedlings can make the leaves thinner and use the resources not used for thicker leaves, for something else.
Scientists are taking what we know from these different forests to try and predict what the long-term consequences of hunting are. Researchers predict that hunting may cause extinction not only of large mammals but also of plant species that depend on those mammals for dispersal. So far, it’s been hard to make general predictions about how hunting can affect plant communities, but we do know that hunting does alter forests and will therefore change the way forests are assembled and grow. We also know that hunting can affect many different organisms ranging from insects to microbes, such as decomposers or plant diseases.
is there such a thing as underwater forests?
Yes there are, unfortunately, I don't know much on this topic. Underwater forests are made up of kelp, which are one of the most productive ecosystems on earth. These kelp disperse through reproductive single-celled units called zoospores. Zoospores are spores with flagellum, which is a long, thin tail-like projection that extends from the spore for locomotion. The dispersal of kelp zoospore depends on the size of the kelp forest. Zoospores near the edge of the kelp forest or in a small forest disperse really far because of stronger water flow, whereas zoospores inside large kelp forests stay near adults, because of less water flow. This work is done by Dr. M.H. Graham at Moss Landing Marine Laboratories.
People rely on kelp forests for their associated animal species, such as lobsters. The extract of kelp is even used for toothpaste! Kelp forests are under threat do to indirect effects by overfishing, direct harvesting of kelp and the animals that live in the kelp forests, and a slew of other things, such as climate change and water pollution. Because kelp forests are so complex, researchers are unsure of how to manage them for the important ecosystem services they provide.
When did you start taking an interest in this kind of stuff?
I became interested in ecology in college. The spring of my sophomore year I took a field botany course in which we spent two weeks in Costa Rica. This was my first small taste of tropical ecology and created an appetite for more, which would have to wait two years. In the meantime, my summer after my sophomore year, I applied to work with one of my professors to do a research project on whether praying mantids ate pollen and how pollen might affect their survival and growth. I continued to pursue this project over the course of my undergraduate career; this project originated my interest in plant-animal interactions. During college, I also became involved in another project that studied the movement and dispersal of salamanders. Salamanders are very cool! My senior year I took a field course in Ecuador, where I became completely fascinated with gradients of diversity. Why are there so many more species in one area than another?
After college, I worked on several research projects including the mating behavior of bowerbirds in Australia and the ecology of chilies. After these different experiences, I started to develop my more specific interest in how animals and microbes structure forest communities.
what is your favorite rainforest animal??
There are so many fascinating organisms that it’s hard for me to have a favorite, but I do enjoy very much the songs of the different species of thrushes, such as the wood thrush and the veery. These birds inhabit deciduous forests in the Eastern United States and are found near water. They are very drab looking: brown with a white belly spotted with brown patches, but the song is beautiful and flutelike, giving the forest a mystical quality. Here is a website I found with its song http://www.learnbirdsongs.com/birdsong.php?id=32
oops, misread the question!....rainforest animals definitly narrows this down! A family of birds called manakins (which also eat fruit and disperse seeds!) have a very interesting courtship display. The males are brightly colored and dance in a group to attract females. The males fly around making snapping and buzzing sounds with their wings; they compete with each other for females. The females come and check them out and pick the one they think is the best. This type of mating behavior, where males gather to compete for females, is called lekking behavior, and the group of males is called a lek. Here is a video showing the dance of the manakin in slow motion: http://www.youtube.com/watch?v=T2Bsu4z9Y3k
Is the rainforest really dying? How can we help to preserve it, as teenagers?
There has been some controversy concerning how much we are affecting rain forests. Several scientists think that through hunting, forest fragmentation, deforestation, climate change, pollution, invasive species and so forth, we are going to cause a chain of events leading to a mass extinction, in which many species go extinct in a very short time. One of the proponents of this is E.O. Wilson, who thinks we will cause about half of the world's species to go extinct in the next 100 years. You should check out some of his books such as, 'The Diversity of Life' or 'The Future of Life'.
In fact right now, many amphibians, such as almost all frogs at high altitude in tropical regions, are going extinct for unknown reasons. Scientists in Panama have seen many frog species going extinct within just a few weeks due to a fungus, called the chytrid, which has been found all over the world. To get an overview of the extent of the current worldwide decline of amphibians and its possible causes check out Amphibiaweb and this article Emerging Infectious Diseases and Amphibian Population Declines by the Centers for Disease Control and Prevention
Many large mammals are going extinct do to hunting and loss of habitat. There is a good summary of this in a paper called 'The empty forest' by KH Redford in BioScience (Vol 42, No 6, pp. 412-422). This would be a good introductory paper to read about the loss of mammal species.
Other scientists are saying maybe we won't go through a mass extinction because more people are moving to the cities and therefore forest will regenerate in the abandoned lands that people left behind. Potentially, plant and animal species could persist in this new forest growth. However, this is very controversial. One reason is because there are different types of forest.
Many forests that are being cut down are very old forests called primary or virgin forests. These forests have been around for hundreds of years and have plant and animal species that are specialized to these forests. In other words, they can only live in these forests. Primary forests tend to have very large trees that live a long time and are open in the understory.
The forests that regenerate, or grow, from abandoned farm lands, are called secondary forests and have different plant and animal species living in them. Secondary forests have lots of undergrowth and lianas, and the trees tend to be spaced closely together. These are very young forests and tend to have less biodiversity than primary forests. Some animals and plants can live in both forest types.
There are also places in the world called 'hotspots'. These areas have almost half of the total diversity of all vascular plants and more than a third of all vertebrates. Hotspots have many endemics, or species that are restricted to those areas and can't live any where else. These hotspots have already lost 90% of there forests.
So, having more people move to the cities may slow mass extinction, but it may not.
There are two important, though harder to understand papers, that are good to read if you are interested in learning more. One is called 'The Uncertain Future of Tropical Forest Species' by Wright and Muller-Landau in Biotropica (Vol. 38, pp.287-301) and a criticism of their work by W. F. Laurance called "Have we overstated the tropical biodiversity crisis?" in Trends in Ecology and Evolution (Vol 22, No. 2 pp.65-70)
So what can you do? I think one good thing is to become educated of what is going on by reading primary and secondary sources. Primary sources are actual papers on the research; these can be difficult to understand if you are not an expert in the field, but you can give it at try and see how it goes. However, you should probably start off with secondary sources, which summarize the results of many different papers in the form of a review or such. The previously mentioned books by E.O Wilson would be a good starting point. You can also read up on research and conservation issues in magazines, such as Science or other sources. You could even start a readling club and ask a teacher to become involved to help guide you through the more difficult readings. Or if there is a university nearby, you could even ask a graduate student who studies rain forests to come in and talk to you or occasionally meet with your reading group. You should also talk with your librarian to teach you or help you find good sources.
If you are interested in learning more about conservation and nature, there is a great camp, called Nature Camp, located in Vesuvius, VA where you can learn more about what you can do to help the environment and you can take classes to learn more about different fauna, such as birds and amphibians. I taught at this camp one summer, and found it fantastic.
There are also opportunites at some universities to become involved in research. You should contact the biology department of your local university for more information if you are interested in becoming directly involved in research.
Another thing you can do is volunteer in a local conservation program, such as the Sierra Club, if you have a local chapter, or a nature center. Depending on what is available, you can help maintain the nature center, like, for example, cleaning aquariums (I did this in NC, cleaning aquariums that housed snakes and turtles!) or helping out the education programs in conservation.
Another thing you can do is write your congressman and let him know that you are interested in conserving nature and you would like him to advocate legislation supporting the environment.
Little things you can do is recycle and, if your high school doesn't recycle, start a recycling club for your high school.
Communicate with people! Build their awareness and let them know more about the fate of tropical forests.
Potentially you could even form a club in your high school that focused on conservation issues in tropical forests. Your club could brainstorm different ways to build awareness in your community and raise money to help protect rain forests.
Here are some links I found that give more information on how you can become involved in a variety of different ways.
Rainforest Action Network
Kids Saving the Rainforest
Save the Rainforest, Inc.
Tropical Rainforest Coalition.
What has been your greatest challenge through all your research?
The process of scientific discovery is a multifaceted process which involves background readings and observations, a question that is interesting and would advance our knowledge, hypotheses that are testable, an experiment designed to answer the question of interest and discern amongst alternative hypotheses, and lastly, interpretation of the results. The details of designing an experiment and coming up with a working methodology requires creativity and knowledge of the system.
My greatest challenge in designing an experiment during my graduate career has been finding enough trees to work with. As I discussed in an earlier question, species diversity in tropical forests can be very high; Panamanian rain forests are no exception! For example, in a 50 hectare plot on Barro Colorado Island, there are approximately 300 tree species. Many of these tree species are rare, and therefore, hard to find.
For most of the experiments I have set up, I have needed to find many individuals of the same species that are spaced a certain distance apart. To do this, I search the forests for trees of the species I need. Finding trees takes a while as I am a neophyte to identifying trees, many species are rare, and clumps of individuals can be widely spaced. I have learned to identity some of the more common species and am continuously learning to identify more species. Because of the dense understory vegetation in secondary forests (for a definition see an earlier question), it is difficult to see more than a few meters away from where one is standing, making it harder to find trees. In addition to finding trees of a certain species, the individuals I find need to be at the beginning of their fruiting season. The flowers and fruits of many species of trees tend to be at the top of the crown, 30 meters up from where I am standing. Many tree crowns are covered in lianas, which are woody vines. These lianas make it difficult for me to distinguish between different types of trees and to see whether there are flowers and fruit up in the canopy.
Are there wolves in the tropical rain forest?
Is it difficult to stay in the area that you are studying? How do you prepare and what do you take with you? Thanks.
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