Urban ecology
Urban ecology is the scientific study of the relation of living organisms with each other and their surroundings in an urban environment. An urban environment refers to environments dominated by high-density residential and commercial buildings, paved surfaces, and other urban-related factors that create a unique landscape. The goal of urban ecology is to achieve a balance between human culture and the natural environment.
Urban ecology is a recent field of study compared to ecology. Currently, most of the information in this field is based on the easier to study species of mammals and birds . To close the gap in knowledge, attention should be paid to all species in the urban space like insects and fish. This study should also expand to suburban spaces with its unique mix of development and surrounding nature. The methods and studies of urban ecology is a subset of ecology. The study of urban ecology carries increasing importance because more than 50% of the world's population today lives in urban areas. It is also estimated that within the next 40 years, two-thirds of the world's population will be living in expanding urban centers. The ecological processes in the urban environment are comparable to those outside the urban context. However, the types of urban habitats and the species that inhabit them are poorly documented which is why more research should be done in urban ecology.
History
Historically, ecology has focused on natural environments, but by the 1970s many ecologists began to turn their interest towards ecological interactions taking place in and caused by urban environments. In the nineteenth century, naturalists such as Malthus, De Candolle, Lyell, and Darwin found that competition for resources was crucial in controlling population growth and is a driver of extinction. This concept was the basis of evolutionary ecology. Jean-Marie Pelt's 1977 book The Re-Naturalized Human, Brian Davis' 1978 publication Urbanization and the diversity of insects, and Herbert Sukopp et al.'s 1979 article "The soil, flora and vegetation of Berlin's wastelands" are some of the first publications to recognize the importance of urban ecology as a separate and distinct form of ecology the same way one might see landscape ecology as different from population ecology. Forman and Godron's 1986 book Landscape Ecology first distinguished urban settings and landscapes from other landscapes by dividing all landscapes into five broad types. These types were divided by the intensity of human influence ranging from pristine natural environments to urban centers.Early ecologists defined ecology as the study of organisms and their environment. As time progressed urban ecology was recognized as a diverse and complex concept which differs in application between North America and Europe. The European concept of urban ecology examines the biota of urban areas, the North American concept has traditionally examined the social sciences of the urban landscape, as well as the ecosystem fluxes and processes, and the Latin American concept examines the effect of human activity on the biodiversity and fluxes of urban ecosystems. A renaissance in the development of urban ecology occurred in the 1990s that was initiated by the US National Science in funding two urban long-term ecological research centers and this promoted the study of urban ecology.
The field of urban ecology is rapidly expanding, with an increasing number of dedicated research centers emerging. Among the pioneers are the Urban Ecology Research Laboratory at the University of Washington, established in 2001, and the Urban Ecology Laboratory at the Costa Rican Distance University, founded in 2008. The UERL in Washington specializes in analyzing urban landscape patterns, ecosystem functions, modeling land cover changes, and developing scenarios for urban adaptation within the state. In contrast, Costa Rica's LEU holds distinction as the world's first research center exclusively devoted to studying tropical urban ecosystems. Research conducted there spans various facets of urban ecology, including biodiversity, the impacts of climate change on cities and their surrounding areas, and the intricate interactions between human activities and urban environments.
Methods
Since urban ecology is a subfield of ecology, many of the techniques are similar to that of ecology. Ecological study techniques have been developed over centuries, but many of the techniques use for urban ecology are more recently developed. Methods used for studying urban ecology involve chemical and biochemical techniques, temperature recording, heat mapping remote sensing, and long-term ecological research sites.Chemical and biochemical techniques
Chemical techniques may be used to determine pollutant concentrations and their effects. Tests can be as simple as dipping a manufactured test strip, as in the case of pH testing, or be more complex, as in the case of examining the spatial and temporal variation of heavy metal contamination due to industrial runoff. In that particular study, livers of birds from many regions of the North Sea were ground up and mercury was extracted. Additionally, mercury bound in feathers was extracted from both live birds and from museum specimens to test for mercury levels across many decades. Through these two different measurements, researchers were able to make a complex picture of the spread of mercury due to industrial runoff both spatially and temporally.Other chemical techniques include tests for nitrates, phosphates, sulfates, etc. which are commonly associated with urban pollutants such as fertilizer and industrial byproducts. These biochemical fluxes are studied in the atmosphere, aquatic ecosystems and soil nematodes. Broad reaching effects of these biochemical fluxes can be seen in various aspects of both the urban and surrounding rural ecosystems.
Temperature data and heat mapping
data can be used for various kinds of studies. An important aspect of temperature data is the ability to correlate temperature with various factors that may be affecting or occurring in the environment. Oftentimes, temperature data is collected long-term by the Office of Oceanic and Atmospheric Research, and made available to the scientific community through the National Oceanic and Atmospheric Administration. Data can be overlaid with maps of terrain, urban features, and other spatial areas to create heat maps. These heat maps can be used to view trends and distribution over time and space.Remote sensing
is the technique in which data is collected from distant locations through the use of satellite imaging, radar, and aerial photographs. In urban ecology, remote sensing is used to collect data about terrain, weather patterns, light, and vegetation. One application of remote sensing for urban ecology is to detect the productivity of an area by measuring the photosynthetic wavelengths of emitted light. Satellite images can also be used to detect differences in temperature and landscape diversity to detect the effects of urbanization.LTERs and long-term data sets
sites are research sites funded by the government that have collected reliable long-term data over an extended period of time in order to identify long-term climatic or ecological trends. These sites provide long-term temporal and spatial data such as average temperature, rainfall and other ecological processes. The main purpose of LTERs for urban ecologists is the collection of vast amounts of data over long periods of time. These long-term data sets can then be analyzed to find trends relating to the effects of the urban environment on various ecological processes, such as species diversity and abundance over time. Another example is the examination of temperature trends that are accompanied with the growth of urban centers. There are currently two active urban LTERs: Central Arizona-Phoenix, first launched in 1997 and housed at Arizona State University and Minneapolis-St. Paul Metropolitan Area. The Baltimore Ecosystem Study was originally funded in 1998 as an urban LTER but as is no longer funded by the National Science Foundation as of 2021.Urban effects on the environment
Humans are the driving force behind urban ecology and influence the environment in a variety of ways - urbanization being a key example. Urbanization is tied to social, economic and environmental processes. There are six core aspects: air pollution, ecosystems, land use, biogeochemical cycles, water pollution, solid waste management, and the climate. Urbanization was driven by migration into cities and the rapid environmental implications that came with it; increased carbon emissions, energy consumption, impaired ecology; all primarily negative. Despite the impacts, the perception of urbanization at present is shifting from challenges to solutions. Cities are home to an abundant amount of financially well-off, knowledgeable and innovative initiators who are increasing the involvement of science in urban policy processes and concepts. The intersection of the multiple processes/integrated systems approach which can easily emerge within a city, includes five characteristics that can emphasize this fundamental shift at a low cost. These solutions are integrated, comprehensive, multifunctional approaches that speak to the social, economic, and cultural contexts of cities. They take into account the chemical, biophysical, and ecological aspects that define urban systems, including lifestyle choices that are interlinked with the culture of a city. However, despite adapting the opportunities that a city can participate in, the results of the concepts that researchers have developed remains uncertain.Modification of land and waterways
Humans place high demand on land not only to build urban centers, but also to build surrounding suburban areas for housing. Land is also allocated for agriculture to sustain the growing population of the city. Expanding cities and suburban areas necessitate corresponding deforestation to meet the land-use and resource requirements of urbanization. Key examples of this are Deforestation in the United States and Europe.Along with manipulation of land to suit human needs, natural water resources such as rivers and streams are also modified in urban establishments. Modification can come in the form of dams, artificial canals, and even the reversal of rivers. Reversing the flow of the Chicago River is a major example of urban environmental modification. Urban areas in natural desert settings often bring in water from far areas to maintain the human population and will likely have effects on the local desert climate. Modification of aquatic systems in urban areas also results in decreased stream diversity and increased pollution.