Tropical ecology

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Tropical ecology is the study of the relationships between the biotic and abiotic components of the tropics, or the area of the Earth that lies between the Tropic of Cancer and the Tropic of Capricorn (23.4378° N and 23.4378° S, respectively). The tropical climate experiences hot, humid weather and rainfall year-round. While many might associate the region solely with the rainforests, the tropics are home to a wide variety of ecosystems that boast a great wealth of biodiversity, from exotic animal species to seldom-found flora. Tropical ecology began with the work of early English naturalists and eventually saw the establishment of research stations throughout the tropics devoted to exploring and documenting these exotic landscapes. The burgeoning ecological study of the tropics has led to increased conservation education and programs devoted to the climate. This climatic zone offers numerous advantages to ecologists conducting a wide array of studies, from rich biodiversity to vast lands untainted by man.

Contents

Origins

The roots of tropical ecology can be traced to the voyages of European naturalists in the late 19th and early 20th centuries. Men who might be considered early ecologists such as Alexander Von Humboldt, Thomas Belt, Henry Walter Bates, and even Charles Darwin sailed to tropical locations and wrote extensively about the exotic flora and fauna they encountered. While many naturalists were simply drawn to the exotic nature of the tropics, some historians argue that the naturalists conducted their studies on tropical islands in order to increase the likelihood that their work might bring about social and political change. [1] In any case, these early explorations and the subsequent writings that came from them comprise much of the early work of tropical ecology and served to spark further interest in the tropics among other naturalists. Henry Walter Bates, for example, wrote extensively about a species of toucan he encountered while traveling along the Amazon River. Bates discovered that if one toucan called out, the other surrounding toucans would mimic his or her call, and the forest would quickly fill with the sounds of toucans; this was one of the first documented studies of animal mimicry. [2] Alexander Von Humboldt voyaged throughout South America, from Venezuela through the Andes Mountains. There, Humboldt and his associate, Aimé Bonpland, stumbled upon an interesting ecological concept. As the pair traveled from the base of the mountains to the peak, they noticed that the species of plants and animals would change according to which climatic zone they were in relative to their elevation. This simple discovery aided the theorization of the life zone concept, which would eventually give way to the popularization of the concept of ecosystems. [2] Another voyager, William Beebe, researched many species of birds in tropical locations and published a large gamut of academic works on his findings that greatly shaped the field of ornithology. According to his biographer Carol Grant Gould, "The effects William Beebe had on science... are enormous and lasting. He made an effective transition between the Victorian natural historian, content to collect and classify the natural world, and the modern experimental biologist." [3] The work of these early pioneers not only lead to an increased interest in the burgeoning field of tropical ecology, but also had far reaching implications for scientific study on the whole.

Conservation and management

Tropical blossom in the Ecuadorian rainforest B02 Ecuador 010 - Plants of the rainforest, February 1985.jpg
Tropical blossom in the Ecuadorian rainforest

Tropical regions are hotspots for biodiversity, so conservation efforts are important to focus on in these places. Many species can be observed and conserved in the tropics. [4] The tropics receive a lot of attention when it comes to conservation and management due to increased public awareness of the significance of tropical ecosystems and the delicacy with which they must be treated. Conservation efforts in the tropics can be difficult to start, as many communities have developed a culture around the ecology in many locations, and in many cases, people make their livelihood off some aspect of the ecology. [5] Conservation measures have multiple benefits to the ecosystem and the community. There are health, economic, and environmental benefits to conserving tropical ecosystems, and conserving these benefits requires communication between local people, governments, and stakeholders. Communication between these groups facilitates the most benefit from conserving tropical ecosystems. [6]

The rainforests are subjects of heightened attention due to the excessive deforestation and logging that occurs in those ecosystems. Deforestation contributes to CO2 emissions, which is a cause of climate change. Much of the deforestation in the tropics is the result of agricultural land use. [7] In the 1980s, the United Nations Food and Agriculture Organization conducted a study that concluded that 15.4 million hectares (100 acres) of tropical forest was lost per year. In addition, 5.6 million hectares were logged each year. This landmark study sparked widespread interest in the tropical ecosystem, and a great number of non-profits and outspoken ecologists engaged in an extended fight to "save the rainforest" that continues today. This battle has manifested itself in a number of ways, one of which is the outcropping of biodiversity institutes in tropical locations dedicated to stopping the excessive deforestation of the landscape, one of the most notable of which was established in Costa Rica. The work of the Costa Rican National Biodiversity Institute (INBio) has served as a model for other biodiversity institutes. First, it must be noted that rainforests harbor the most alkaloid-producing plants of any biome; alkaloids are compounds that are crucial to the production of Western drugs. Due to the abundance of these compounds, pharmaceutical companies all over the world look to the rainforests for new medicinal treatments. In the early 1990s, the heads of INBio signed a deal with the pharmaceutical behemoth Merck that called for cooperation between the two entities in discovering and exploring new natural treatments in the Costa Rican rainforests. Ecologists, government officials, and corporations alike praised this decision as decisive progress in an ongoing struggle to work cooperatively in utilizing tropical biodiversity while ensuring the stability of tropical ecosystems.

Significance of ecology in the tropics

Vicuna Atacama, Chile Vicuna Atacama, Chile.jpg
Vicuña Atacama, Chile

  It is advantageous for ecologists and naturalists to study plants, animals, and ecosystems in the tropical climate for a number of reasons. For one, the tropics are home to a wide array of ecosystems, from rainforests to deserts. In that sense, the tropics are a great place for ecologists to conduct diverse studies without traveling too far from a research center. With the large amount of biodiversity present in the tropics, it is a good access point for research. Most research in the tropics has been done on species richness, however more research needs to be done on other aspects of the tropics. [8] Secondly, the temperature in the tropics rarely hinders plant growth and activity; flora can be studied nearly year round, as cold weather never stunts plant activity. In addition to climatic reasons, the traditionally sparse population of the tropics has greatly aided research in the area, as the landscape is largely untainted by mankind and machinery. While this may not be the case so much as of late, the vast amounts of untapped land in the tropics still make for prime research territory. Finally, the tropics are valuable to ecologists because they are home to some of the oldest lands on Earth, including Chile's Atacama Desert and Australia's Peneplain. Thus, plant communities have been growing and evolving for millions of uninterrupted years, which makes for interesting study. That being said, while it may be advantageous to study ecology in the tropics, this is not to say that it is without difficulty. The ecosystems native to the tropics and the biodiversity they boast are dwindling. Half of the species located in biodiversity hotspots are in danger of extinction, and many of the plants with potential medicinal uses are dying off. In this sense, ecological study in the tropics is not as easily conducted as it once was; this is the reason why much of the modern ecological work in the field is aimed towards conservation and management as opposed to general research.

See also

Related Research Articles

Deforestation Conversion of forest to non-forest for human use

Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. The most concentrated deforestation occurs in tropical rainforests. About 31% of Earth's land surface is covered by forests at present. This represents a one-third loss from the existing forest cover before the expansion of agriculture, a half of that loss ocurring in the last century. Between 15 million to 18 million hectares of forest, an area the size of Belgium, are destroyed every year, on average 2,400 trees are cut down each minute. The Food and Agriculture Organization of the United Nations defines deforestation as the conversion of forest to other land uses. "Deforestation" and "forest area net change" are not the same: the latter is the sum of all forest losses (deforestation) and all forest gains in a given period. Net change, therefore, can be positive or negative, depending on whether gains exceed losses, or vice versa.

Biodiversity Variety and variability of life forms

Biodiversity is the biological variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic, species, and ecosystem level. Terrestrial biodiversity is usually greater near the equator, which is the result of the warm climate and high primary productivity. Biodiversity is not distributed evenly on Earth, and is richer in the tropics. These tropical forest ecosystems cover less than ten percent of earth's surface, and contain about ninety percent of the world's species. Marine biodiversity is usually higher along coasts in the Western Pacific, where sea surface temperature is highest, and in the mid-latitudinal band in all oceans. There are latitudinal gradients in species diversity. Biodiversity generally tends to cluster in hotspots, and has been increasing through time, but will be likely to slow in the future as a primary result of deforestation. It encompasses the evolutionary, ecological, and cultural processes that sustain life.

Habitat conservation

Habitat conservation is a management practice that seeks to conserve, protect and restore habitats and prevent species extinction, fragmentation or reduction in range. It is a priority of many groups that cannot be easily characterized in terms of any one ideology.

Tropical rainforest Forest in areas with heavy rainfall in the tropics

Tropical rainforests are rainforests that occur in areas of tropical rainforest climate in which there is no dry season – all months have an average precipitation of at least 60 mm – and may also be referred to as lowland equatorial evergreen rainforest. True rainforests are typically found between 10 degrees north and south of the equator ; they are a sub-set of the tropical forest biome that occurs roughly within the 28-degree latitudes. Within the World Wildlife Fund's biome classification, tropical rainforests are a type of tropical moist broadleaf forest that also includes the more extensive seasonal tropical forests.

Applied ecology

Applied ecology is a sub-field within ecology that considers the application of the science of ecology to real-world questions. It is also described as a scientific field that focuses on the application of concepts, theories, models, or methods of fundamental ecology to environmental problems.

Restoration ecology Scientific study of renewing and restoring ecosystems

Restoration ecology is the scientific study supporting the practice of ecological restoration, which is the practice of renewing and restoring degraded, damaged, or destroyed ecosystems and habitats in the environment by active human interruption and action. Effective restoration requires an explicit goal or policy, preferably an unambiguous one that is articulated, accepted, and codified. Restoration goals reflect societal choices from among competing policy priorities, but extracting such goals is typically contentious and politically challenging.

Reconciliation ecology Study of maintaining biodiversity in human-dominated ecosystems

Reconciliation ecology is the branch of ecology which studies ways to encourage biodiversity in human-dominated ecosystems. Michael Rosenzweig first articulated the concept in his book Win-Win Ecology, based on the theory that there is not enough area for all of earth’s biodiversity to be saved within designated nature preserves. Therefore, humans should increase biodiversity in human-dominated landscapes. By managing for biodiversity in ways that do not decrease human utility of the system, it is a "win-win" situation for both human use and native biodiversity. The science is based in the ecological foundation of human land-use trends and species-area relationships. It has many benefits beyond protection of biodiversity, and there are numerous examples of it around the globe. Aspects of reconciliation ecology can already be found in management legislation, but there are challenges in both public acceptance and ecological success of reconciliation attempts.

Biological Dynamics of Forest Fragments Project

The Biological Dynamics of Forest Fragments Project is a large-scale ecological experiment looking at the effects of habitat fragmentation on tropical rainforest. The experiment which was established in 1979 is located near Manaus in the Brazilian Amazon rainforest. The project is jointly managed by the Amazon Biodiversity Center and the Brazilian Institute for Research in the Amazon (INPA).

Guanacaste Conservation Area

Guanacaste Conservation Area is an administrative area which is managed by the Sistema Nacional de Areas de Conservacion (SINAC) of Costa Rica for conservation in the northwestern part of Costa Rica. It contains three national parks, as well as wildlife refuges and other nature reserves. The area contains the Area de Conservación Guanacaste World Heritage Site, which comprises four areas.

Tropical rainforest conservation

Building blocks for tropical rainforest conservation include ecotourism and rehabilitation. Reforestation and restoration are common practices in certain areas to try to increase rainforest density. By communicating with the local people living in, and around, the rainforest, conservationists can learn more about what might allow them to best focus their efforts. Rainforests are globally important to sustainability and preservation of biodiversity. Although they may vary in location and inhabited species of plants and animals, they remain important worldwide for their abundance of natural resources and for the ecosystem services. It is important to take into consideration the differing species and the biodiversity that exists across different rainforest types in order to accurately implement methods of conservation.

Earthwatch Institute Scientific field research institute

Earthwatch Institute is an international environmental charity founded as Educational Expeditions International in 1971 near Boston (USA) by Robert A. Citron and Clarence Truesdale, then superintendent of Vermont public schools. It is one of the largest global underwriters of scientific field research in archaeology, paleontology, marine life, biodiversity, ecosystems and wildlife. For over forty years, Earthwatch has delivered a unique citizen science model to raise funds and recruit individuals, students, teachers and corporate fellows to participate in critical field research to understand nature's response to accelerating global change. Earthwatch's work supports hundreds of Ph.D. researchers across dozens of countries, conducting over 100,000 hours of research annually.

Island ecology is the study of island organisms and their interactions with each other and the environment. Islands account for nearly 1/6 of earth’s total land area, yet the ecology of island ecosystems is vastly different from that of mainland communities. Their isolation and high availability of empty niches lead to increased speciation. As a result, island ecosystems comprise 30% of the world’s biodiversity hotspots, 50% of marine tropical diversity, and some of the most unusual and rare species. Many species still remain unknown.

La Suerte Biological Field School

La Suerte Biological Field School, located in Northeastern Costa Rica, is one of two field schools operated by the Maderas rainforest conservancy. The site is situated in a tropical rainforest basin. It houses courses in primatology, ecology, botany, and other courses related to the flora and fauna of Northeastern Costa Rica. This lowland Neotropical region remains one of the most biologically diverse in the world. The field station encompasses 700 acres (2.8 km2) containing a wealth of habitats including primary and secondary forests, swamps, marshes and pasture. In addition, much of the property lies along the Rio La Suerte, a flowing river that empties into the Caribbean at Tortuguero National Park.

Forest restoration

Forest restoration is defined as “actions to re-instate ecological processes, which accelerate recovery of forest structure, ecological functioning and biodiversity levels towards those typical of climax forest” i.e. the end-stage of natural forest succession. Climax forests are relatively stable ecosystems that have developed the maximum biomass, structural complexity and species diversity that are possible within the limits imposed by climate and soil and without continued disturbance from humans. Climax forest is therefore the target ecosystem, which defines the ultimate aim of forest restoration. Since climate is a major factor that determines climax forest composition, global climate change may result in changing restoration aims.

David Lindenmayer

David Lindenmayer,, is an Australian scientist and academic. His research focuses on the adoption of nature conservation practices in agricultural production areas, developing ways to improve integration of native forest harvesting and biodiversity conservation, new approaches to enhance biodiversity conservation in plantations, and improved fire management practices in Australia. He specialises in large-scale, long-term research monitoring programs in south-eastern Australia, primarily in forests, reserves, national parks, plantations, and on farm land.

William F. Laurance American conservationist

William F. Laurance, also known as Bill Laurance, is Distinguished Research Professor at James Cook University, Australia and has been elected as a Fellow of the Australian Academy of Science. He has received an Australian Laureate Fellowship from the Australian Research Council. He held the Prince Bernhard Chair for International Nature Conservation at Utrecht University, Netherlands from 2010 to 2014.

Rodolfo Dirzo is a professor, conservationist, and tropical ecologist. He is a Bing Professor in environmental science at Stanford and a senior fellow at the Stanford Woods Institute for the Environment. His research interests mainly focus on plant-animal interactions, evolutionary ecology, and defaunation in the tropics of Latin America, Africa, and the Central Pacific. He was a member of the Committee on A Conceptual Framework for New K-12 Science Education Standards, co-authoring the framework in 2012, and continues to educate local communities and young people about science and environmental issues. 

Julie Sloan Denslow is an American botanist, ecologist and biologist. She grew up in South Florida, and always loved nature. She graduated from Coral Gables Senior High School in 1960. She has contributed to the field of ecology through her work with and research of tropical ecosystems. Earlier in her career, she spent significant time in the field in tropical locations such as Costa Rica and Panama, as well as in temperate locations in Louisiana. and later on in her career she worked more in the office and classroom, but still spent the occasional day in the field. She has focused on research involving the ecology of exotic invasive plant species, and on ecosystem reactions and recovery following disturbances. Denslow is also a strong supporter of gender equality in the natural sciences, pushing for equal representation of women involved in tropical research and leadership during a 2007 Gender Committee Meeting within the Association for Tropical Biology and Conservation (ATBC). Her most notable contribution to tropical research is her paper "Gap Partitioning among Tropical Rainforest Trees", published in 1980.

Winifred Hallwachs U.S. entomologist and tropical ecologist

Winifred Hallwachs is an American tropical ecologist who helped to establish and expand northwestern Costa Rica's Área de Conservación Guanacaste (ACG). The work of Hallwachs and her husband Daniel Janzen at ACG is considered an exemplar of inclusive conservation.

Shahid Naeem

Shahid Naeem is an ecologist and conservation biologist and is a Lenfest Distinguished professor and chair in the Department of Ecology, Evolution, and Environmental Biology at Columbia University. Naeem is the author of Biodiversity, Ecosystem Functioning, and Human Well-Being, and has published over 100 scientific articles.

References

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