Land use dynamics and ecological transition: the case of South Florida
Post on 05-Aug-2016
Land use dynamics and ecological transition: the case ofSouth Florida
ROBERT T. WALKER* and WILLIAM D. SOLECKIDepartment of Geography, Florida State University, Tallahassee, FL 32306-2050, USA
CHRISTINE HARWELLRosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149, USA
This study examines the process of land use change in South Florida. Through this discussion, a conceptual modelof ecological transition is developed and presented. The model is built on the general principles of neoclassicaleconomic theories of land rent, behavioral models of resource use, and an historical geographic account of envi-ronmental change. Central to the paper is the specification of the theoretical link between demographics, market andservice demands, land use, and ecological change. This study focuses on the nature and drivers of environmentalchange that has occurred in South Florida since 1900. The region studied includes the southern Florida Evergladesand the surrounding area. The analysis determines that massive land use/land cover has taken place in the region,particularly since the end of World War II. These landscape changes are conceptualized by a model that linksregional demand for both agricultural and residential land through the agency of hierarchical forces. In this model,landscape evolution and natural areas encroachment are articulated as a dynamic process in which the regime ofinteraction between human systems and land use changes. Three main time periods for regional ecological transitionare defined: (1) frontier closure; (2) articulation of a system of cities with coupled agricultural hinterlands servingnational and international markets. Differing land use change dynamics are identified as specific to each time period.
Keywords: land use; ecological transition; hierarchical model
The impact of human population on environmental sustainability is complex and varies from system tosystem. Historical change involving technological and cognitive adaptations, as well as the hierarchicalarticulation of impacting forces, complicate specification of such impacts (Blaikie and Brookfield, 1987).The Human Dominated Systems Directorate (HDSD) of the U.S. Man and the Biosphere Program hasaddressed several of these issues in a case study of South Florida. In this region extensive ecologicalresources of international significance exist in close proximity to burgeoning urban populations (Long,1995). This paper presents a discussion of historical changes in factors affecting the relationship betweenhuman and ecological systems. The policy debate surrounding sustainability and maintenance of scarceecological resources can only be resolved by dealing with the human and ecological factors in such anintegrated fashion. The designation of national parks and wilderness land is becoming increasinglyproblematic in the current era of rapidly growing global population and political conflict (Solecki, 1994;
*Author to whom correspondence should be addressed.Sustainability and sustainable development are key concepts in discussions on environmental degradation; unfortunately, they arenot well defined. We choose not to engage in this discourse, however, and rely instead on a largely intuitive notion of sustainability.For human systems, sustainability implies the reproducibility of the social unit, through adequate economic performance. Alsoinforming our use of the term is an ecological dimension, similar to the human system usage; that is, ecological sustainabilityimplies reproducibility of the resident ecosystem. Thus, sustainability would seem to suggest harmonious longterm relationsbetween human systems and the environment, when taken as a term of sufficient generality to include natural and humandimensions.
Urban Ecosystems, 1997, 1, 3747
1083-5155 1997 Chapman & Hall
West and Brechin, 1991). Conservation of natural resources will inevitably require an adaptive equilib-rium between natural and human systems.
Land use and, in particular, land use dynamics are of key importance to conceptualizing the relation-ship between natural and human systems (Turner and Meyer, 1994). Technological changes (particularlyin agriculture), government interventions (e.g. infrastructure development), and the evolution of envi-ronmental cognition all affect land use of dynamics and can be addressed theoretically by referring toconcepts from the frontier development literature and bid-rent theory, which stems from Von Thunen(Nerlove and Sadka, 1991) and was initially elaborated for the urban case by Alonso (1964). Theobjective of this paper is to identify the main social forces that have affected ecological resources inSouth Florida and to provide a theoretical framework useful to the policy debate surrounding the issueof ecological sustainability in South Florida and elsewhere.
South Florida developmentHDSD research has focused on South Florida, which consists of seven counties Broward, Collier, Dade,Hendry, Lee, Monroe, and Palm Beach that had a 1990 population of 4.6 million; about 87% of arearesidents live on the eastern coastal strip (Winsberg et al., 1994). The Gulf Coast to the west is lessdensely settled but has recently experienced accelerated growth rates. Agriculture is practiced along theeast coast urban fringe, below Lake Okeechobee, and on larger dispersed patches toward the west(Winsberg et al., 1994). Much interior land is under government jurisdiction (federal and state), desig-nated as water conservation and wildlife management areas. Ecological resources in the region includethe Everglades, as well as extensive areas of cypress and pine forest. Between 1975 and 1986, about 2000km2 of natural areas were converted to human use in the region, which represented 13% of the naturalland at the start of the period. This represents an annual rate of conversion of 1.1%, 60% greater than theglobal rate of tropical rainforest loss in the 1980s (FAO, 1992). An estimated 50% of the originalecosystem has been lost since 1900, representing a conversion of 6000 km2 of Everglades wetlands andpine forest and the complete loss of three of seven physiographic landscapes in the original system (Daviset al. 1994). Conversion of Everglades land to human use through extensive drainage and flood controlhas had tremendous impact on the natural hydrologic regime; this is a major factor in several currentenvironmental problems, including reduced bird populations, disappearance of wetlands, and declines inaquifer recharge (Browder et al., 1994).
Until the end of the 19th century much of the land cover in South Florida remained in a natural state(see Fig. 1). Indigenous populations altered the landscape through hunting, foraging, and use of fire, butmuch of the ecological integrity of the Everglades watershed remained intact until the early 1900s. In1900, only 5000 people inhabited the whole South Florida region, mostly in 16 small settlements,excluding Key West which at the time had a population of approximately 18 000. Very few individualsactually lived within the boundaries of the Everglades watershed. The largest settlement at the time wasMiami, with a 1896 population of about 300 (Chapman, 1991). All 16 settlements were coastal inorientation and were located no more than a mile from estuaries and beaches. A minimal amount of landwas in agricultural production, but little commercial agricultural production was present (Snyder andDavidson, 1994). Much of the produce probably fulfilled both the subsistence needs of the settlers andthe consumption demands of a population of elite tourists. Strong nonlocal demand had not developedfor the current staples of the region (vegetables, cattle, and sugar), and markets remained relativelylimited for agricultural produce, serving only the urban centers and their seasonal visitors. The comple-tion of a railway to Miami in 1896, making the coastal area much more accessible to tourists and potentialresidents, dramatically affected local land use by opening the region to extensive residential and com-mercial development.
By 1930, the population of Southeast Florida had grown to approximately 230 000, as immigration of
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retirees, tourists, and other settlers began to spread out along the coastal ridge. Regional growth rates inSoutheast Florida during this time were among the highest recorded by the U.S. Census, with decadalgrowth exceeding 100% from 1900 to 1930. This growth further encouraged the construction of the waterand flood control systems now present in the region. The opening of South Florida by railroad andhighway and the hydrologic alteration in the interest of drainage and flood protection closed the frontier,with the appropriation of unclaimed lands to public and private ownership. Subsequently, the ecologicalresource base faced substantial exposure to human activities.
Although population increased significantly, the vast majority remained tightly clustered within a fewmiles of the Atlantic coast. Only near Miami did settlement occur west of the coastal ridge in anymagnitude. The amount of land converted to urban use remained small, accounting for a minusculeproportion of the entire watershed. Most tourists and retirees sought the natural amenities of the coast.High-density development took place right at the waters edge or at nearshore locations such as the PalmBeaches, Miami, and Miami Beach. In contrast, agricultural production was already a substantial con-sumer of land. Along the Atlantic coast, three large agricultural districts had developed on lands just
Figure 1. South Florida land cover 1900. Source: Department of Geography, Florida State University.
Land use dynamics and ecological transition in South Florida 39
beyond the urban fringe. A fourth emerged south of Lake Okeechobee in the vast muckland soil area,where farmlands grew to over 55 000 ha by 1943 (30 353 ha of vegetables, 12 141 ha of sugar cane, 2024ha of pasture and miscellaneous minor crops) (Snyder and Davidson, 1994).
Population growth during the 1930s and 1940s was less dramatic than during the earlier period, butstrong enough to reach 720 000 by 1950. In the early 1950s the general regional pattern of land useremained largely the same as before, although urban areas were beginning to expand. Immigrants tookadvantage of the promise of flood control to develop urban settlements. Much of this residential growthoccurred in Dade and Broward counties, filling in the unoccupied and agricultural spaces in and aroundthe cities of Miami and Ft. Lauderdale.
Since the early 1950s, South Florida has been the site of tremendous land use modification andconversion. There were several driving forces behind this, including increased national demand forwinter vegetables and fruits and rapid population growth in response to tourism and changing residentialpreferences, particularly among retirees. In 1947, a series of massive floods increased the impetus for theexpansion of the water projects in the region. The federal government responded to the hurricane-related
Figure 2. South Florida land cover 1973. Source: Department of Geography, Florida State University.
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floods by building dikes around Lake Okeechobee and by changing its water management goals fromdrainage to flood control. Simultaneously, strong nonlocal markets for Floridas winter vegetables andfruits grew throughout the country as the regions transportation and product distribution system becamemore integrated into northern and midwestern markets. Residents in these areas increasingly wanted andcould afford fresh winter produce (Winsberg, 1991). Agricultural production was also stimulated byinternational events. The Cuban Revolution sparked a series of tariff increases on imported sugar thatfostered rapid growth in sugar cane production. When Castro came to power in 1959, about 19 020 haof sugar cane were harvested just south of Lake Okeechobee [a.k.a. Everglades Agricultural Area(EAA)]. By 1986 these lands had grown to 161 880 ha (Salley, 1986).
Additional land use pressures came from increased population in the region, which reached nearly 2.3million in the four southeastern counties by 1970. Huge streams of in-migrants came from the north-eastern and midwestern United States and from other countries, particularly from Latin America. Muchof the housing development undertaken to accommodate these individuals was in the form of land-intensive, low-rise, single-family dwellings. Demand for land originated primarily from retirees, otherin-migrants, and tourists. Tourism, focused largely on coastal and near-coastal locations, maintained ahigh central-strip rent profile which promoted decentralized residential choices by retirees and nonre-tirees alike. Residential developments with detached homes and landscaped lots near land-extensiverecreational amenities such as golf courses increased dramatically during this period. Sharp growth in theconsumer base (both local residents and tourists) increased demand for locally grown produce andthereby encouraged further agricultural development (M. Winsberg, personal communication, 1995).
The impact of increased agricultural activity and in-migration on land use was dramatic, and tremen-dous change took place from the early 1950s to the mid-1970s. Two of the most obvious changes werethe rapid increase of agricultural production in the EAA and the increase of urban-oriented land use. Analmost continuous strip of development emerged beside the Atlantic (see Fig. 2). Urban land uses becamewell established in the extreme southeastern part of the region, particularly around the cities of Miamiand Fort Lauderdale and along the entire coast north to West Palm Beach.
Rapid urbanization resulted in three additional land cover dynamics. From 1953 to 1975, most of theremaining upland pine forests and near-shore agricultural areas were converted to urban land. In 1975,just a few remnants of the coastal pine forest were evident, and increasingly agricultural production wasfound only in isolated pockets situated between the urban fringe and the publicly owned conservationlands to the west. Agricultural lands were largely reduced to a narrow transition between the urbanizedcoast and the interior Everglades area. However, as Atlantic coastal land was converted to urban use,certain inland parcels were taken under agricultural production. Such shifts were particularly evident inthe southeastern and northeastern sections of the region.
By the late 1980s, the current land use pattern was largely in place, although certain earlier processesintensified (see Fig. 3). The continuous strip of urbanized land along the Atlantic coast became moreclearly defined and pronounced. Much conversion to urban use from the 1970s to the late 1980s occurredon lands within or adjacent to the already settled areas. The coastal urban strip clearly dominated aroughly 100-mile stretch along the coast, and the agricultural zone separating coasta...