John Jeffrey Ewel is an emeritus professor and tropical succession researcher in the department of biology at the University of Florida. Most of his research was conducted through experimental trials to understand ecosystem processes in terrestrial and tropical environments. The results of the research provided the ability to further comprehend forest structure and management, as well as its nutrient dynamics. The primary research conducted dealt with the beginning stages of the regrowth and recovery following agriculture practices. Ewel also participated in studies regarding invasive species and restoration ecology. [1]
As an undergraduate, Ewel studied forestry at the State University of New York College of Environmental Science and Forestry. [2] He focused on the biology and management of natural resources and the environment, and after graduation in 1962, he attended a graduate summer program in Puerto Rico. He remained in Puerto Rice to work for the U.S. Forest Service Institute of Tropical Forestry [3] to examine the effects of irradiation on a tropical forest. In 1963, Joe Tosi hired Ewel to work in an ecological mapping of Venezuela. [1]
After three years, Ewel returned to the United States and completed his M.S degree with Hugh Popenoe at the University of Florida, focusing on litter decay in Guatemalan second-growth vegetation. His Ph.D was completed by working under Howard T. Odum to study the succession in three sites in Costa Rica and two sites in Puerto Rico.
In 1971, University of Florida hired Ewel. While he was working in UF, he was also active in the formation of Corcovado National Park in Costa Rica from 1974 to 1975. In 1990, Ewel became the President of ATB, serving on the Board of Directors and advising for multiple committees at the Organization for Tropical Studies. In 1994, he retired from the University of Florida and became director of the U.S. Forest Service's Institute of Pacific Islands Forestry, r. d responsible for research as well as outreach programs in American Samoa, Commonwealth of Northern Marines, Guam, Hawaii, Marshall Islands, Micronesia, and Palau. In 2005, he retired from U.S. Forest Service, and in 2015 became an Honorary Fellow at the Association of Tropical Biology and Conservation. As an Emeritus Professor at the University of Florida, he still publishes occasionally. [1] [4] [5] In 2017 Ewel was named a Fellow of the American Association for the Advancement of Science, "for distinguished contributions to the field of ecology, particularly to our understanding of tropical ecosystem functioning and management". [6]
Ewel's research was conducted on successional landscapes by examining the regrowth and recovery following agriculture practices in Guatemala, Sarawak, Puerto Rico, and Costa Rica. He examined the succession in its natural occurrence as well as in some cases were human-induced second growth by burning the forest to represent a farmer clearing a field for crop production. Other research he had conducted had examined the tropical succession using the gradients of temperature and moisture to gather more data for further analysis. [7]
Ewel and his fellow researchers, conducted two experiments in Costa Rica, at Centro Agronómico Tropical de Investigación y Enseñanza, [8] The variables of the experiments were to investigate the plant's productivity, their nutrient loss, and interactions with other species of plants, competitors, as well as their consumers. Examined the plant's resistance to pesticides as well as soil fertility after erosion of harvesting annual crops. [7]
In the 1970s, Ewel and his colleges chose certain aquatic habitats with either a nutrient-rich (heavily polluted) environment or a nutrient-poor environment. The researchers added little clusters of water hyacinth to each environment. The results showed that the heavily nutrient-rich aquatic environment had extremely abundant and heavily dense water hyacinths compared to the water hyacinths growing in the nutrient-poor aquatic environment, thus showing human activities alter the fundamental stability of that ecosystem. Since then, more research was conducted to understand changes due to land use by humans and develop new methods to manage the ecosystems in a more sustainable manner. [7]
Books: [9]
Book chapters: [9]
An ecosystem is a system that environments and their organisms form through their interaction. The biotic and abiotic components are linked together through nutrient cycles and energy flows.
Tropical rainforests are dense and warm rainforests with high rainfall typically found between 10° north and south of the Equator. They are a subset of the tropical forest biome that occurs roughly within the 28° latitudes. Tropical rainforests are a type of tropical moist broadleaf forest, that includes the more extensive seasonal tropical forests. True rainforests usually occur in tropical rainforest climates where no dry season occurs; all months have an average precipitation of at least 60 mm (2.4 in). Seasonal tropical forests with tropical monsoon or savanna climates are sometimes included in the broader definition.
Daniel Hunt Janzen is an American evolutionary ecologist and conservationist. He divides his time between his professorship in biology at the University of Pennsylvania, where he is the DiMaura Professor of Conservation Biology, and his research and field work in Costa Rica.
Ecosystem ecology is the integrated study of living (biotic) and non-living (abiotic) components of ecosystems and their interactions within an ecosystem framework. This science examines how ecosystems work and relates this to their components such as chemicals, bedrock, soil, plants, and animals.
The intermediate disturbance hypothesis (IDH) suggests that local species diversity is maximized when ecological disturbance is neither too rare nor too frequent. At low levels of disturbance, more competitive organisms will push subordinate species to extinction and dominate the ecosystem. At high levels of disturbance, due to frequent forest fires or human impacts like deforestation, all species are at risk of going extinct. According to IDH theory, at intermediate levels of disturbance, diversity is thus maximized because species that thrive at both early and late successional stages can coexist. IDH is a nonequilibrium model used to describe the relationship between disturbance and species diversity. IDH is based on the following premises: First, ecological disturbances have major effects on species richness within the area of disturbance. Second, interspecific competition results in one species driving a competitor to extinction and becoming dominant in the ecosystem. Third, moderate ecological scale disturbances prevent interspecific competition.
Forest ecology is the scientific study of the interrelated patterns, processes, flora, fauna and ecosystems in forests. The management of forests is known as forestry, silviculture, and forest management. A forest ecosystem is a natural woodland unit consisting of all plants, animals, and micro-organisms in that area functioning together with all of the non-living physical (abiotic) factors of the environment.
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.
Freshwater swamp forests, or flooded forests, are forests which are inundated with freshwater, either permanently or seasonally. They normally occur along the lower reaches of rivers and around freshwater lakes. Freshwater swamp forests are found in a range of climate zones, from boreal through temperate and subtropical to tropical.
Charles A. S. Hall is an American systems ecologist and ESF Foundation Distinguished Professor at State University of New York in the College of Environmental Science & Forestry.
William Mitsch is an ecosystem ecologist and ecological engineer who was co-laureate of the 2004 Stockholm Water Prize in August 2004 as a result of a career in wetland ecology and restoration, ecological engineering, and ecological modelling.
Mangrove ecosystems represent natural capital capable of producing a wide range of goods and services for coastal environments and communities and society as a whole. Some of these outputs, such as timber, are freely exchanged in formal markets. Value is determined in these markets through exchange and quantified in terms of price. Mangroves are important for aquatic life and home for many species of fish.
A nutrient cycle is the movement and exchange of inorganic and organic matter back into the production of matter. Energy flow is a unidirectional and noncyclic pathway, whereas the movement of mineral nutrients is cyclic. Mineral cycles include the carbon cycle, sulfur cycle, nitrogen cycle, water cycle, phosphorus cycle, oxygen cycle, among others that continually recycle along with other mineral nutrients into productive ecological nutrition.
Ariel E. Lugo is a scientist, ecologist and former Director of the International Institute of Tropical Forestry (IITF) within the USDA United States Forest Service, based in Puerto Rico. He is a founding member of the Society for Ecological Restoration and Member-at-Large of the Board of the Ecological Society of America.
Carl F. Jordan is Professor Emeritus, Odum School of Ecology, University of Georgia.
Katherine Carter Ewel is a Professor Emeritus at the University of Florida's School of Forest Resources and Conservation. She is an ecosystem, forest, and wetlands ecologist who has worked in Florida for much of her career, focusing much of it on cypress swamps, pine plantations, and mangrove forests in the Pacific. Ewel served as the vice-president of the Society of Wetland Scientists in 2003, becoming president in 2004 and now since 2005, a past president. She has now retired and lives near Gainesville, Florida.
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.
Amy D. Rosemond is an American aquatic ecosystem ecologist, biogeochemist, and Distinguished Research Professor at the Odum School of Ecology at the University of Georgia. Rosemond studies how global change affects freshwater ecosystems, including effects of watershed urbanization, nutrient pollution, and changes in biodiversity on ecosystem function. She was elected an Ecological Society of America fellow in 2018, and served as president of the Society for Freshwater Science from 2019-2020.
Grizelle González is a soil ecologist working for the United States Forest Service in San Juan, Puerto Rico. She is known for her work on soil ecology, nutrient cycling, and ecosystem ecology at the Sabana Field Research Station in Puerto Rico.
The Tropical Wet Forests are a Level I ecoregion of North America designated by the Commission for Environmental Cooperation (CEC) in its North American Environmental Atlas. As the CEC consists only of Mexico, the United States, and Canada, the defined ecoregion does not extend outside these countries to Central America nor the Caribbean.
Cheryl Palm was an American agricultural scientist who was Professor of Agricultural and Biological Engineering at the University of Florida. Her research considers tropical land use and ecosystem function, including carbon and nutrient dynamics. She was the former Chair of the International Nitrogen Initiative and a Fellow of the American Association for the Advancement of Science and American Society of Agronomists.