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This chapter presents a version of human ecology called practical ecology. It argues that the application of the Human Ecosystem Model (HEM) as an organizing concept for resource management, environmental decision-making, and human ecological research is both real-world and worldly. Ecosystem theory is to be tempered by the complexity of practice. In formulating the HEM, the scientists’ inspiration comes from the work of Goethe, who was both a scientist and a poet. The challenge of combining art and science brings these scientists closer to Goethe’s ideal. They emphasize that the HEM is a menu of possibility organized by a logical structure that permits one to learn how the components and variables of the human ecosystem respond to particular forces of environmental change.

This chapter examines the Human Ecosystem Model (HEM), which began as a seedling in the late 1960s and has grown and developed into a middle-aged forest today. Human ecosystem is defined as a coherent system of biophysical and social factors capable of adaptation and sustainability over time. Coherence is relative and varying within human ecosystems. There can be “tight coherence” between available energy flows and economic activity, as when a scarcity of petroleum reduces industrial production and raises costs. There can also be “loose coherence,” such as the relationship between available water supplies and the performance of educational institutions. The chapter also elaborates on some of the other key words from the given definition of human ecosystem, such as capability, adaptation, and sustainability.

This chapter analyzes the genealogy of the Human Ecosystem Model (HEM), which includes portions of ecosystem biology and the roots of human ecology. The initial and repeated efforts at taxonomy (identification of component parts) were followed by efforts to understand processes (identification and measurement of flows) as well as issues of agency, efficacy, and evolutionary change. All are foundations for understanding the structure and dynamics of human ecosystems. Studies of the patterns and processes in ecosystems emphasize the diversity and complexity of the elements affecting these systems. This complexity has generally enabled biologists to exclude human behavior from their models and social scientists to remain largely at the level of metaphor when applying ecological concepts to human behavior.

This chapter demonstrates how the Human Ecosystem Model (HEM) offers a unity of understanding with shared concepts, a framework, and a model for resolving complex human ecosystem problems. With it, decision-makers from different organizations—public and private—may coordinate their work with that of local citizens. The emphasis is on the whole system, which combines issues such as trends in crime, housing, education, health, natural resources, and community stability into an integrated network. The chapter illustrates how the framework and model was applied in a major city in the United States: Baltimore, Maryland. The Baltimore story emphasizes that certain universal problems and solutions confront all human societies. The universality of problems and the search for integrated solutions required a framework like the HEM to identify, apply, and store learning.

This introductory chapter discusses how environmental scientists, managers, and other professionals need to intensify their search for cross-cultural models of resource systems that include the forces driving human desires. Socio-cultural variables as both cause and consequence of system change will need to be joined to the traditional biophysical concerns of the ecologist, forester, conservationist, range manager, park superintendent, and rural agriculturalist. Worldwide, disparate indicators of ecosystem stress abound. Some of these challenges include geochemical flux due to pollution, the accumulating inventory of toxic chemicals, a collapsing world fishery, biotic mixing, accelerating loss of coral reefs, desertification, and more. The chapter then introduces the Human Ecosystem Model (HEM) as a possible solution to these problems.

This chapter draws on lessons learned from prior application of the HEM and includes those lessons in a modest revision of the early work. It details each component and variable by providing a general definition and description, suggesting ways that the variable can be measured, and giving selected examples of how a variable may influence other variables of the human ecosystem. The passage of time and the application of the model in many situations have left most of those early components and variables intact, with only a few key additions and deletions. The chapter aims to provide the HEM user with an integrated set of social, economic, and ecological measures that can be collected over time.

This chapter discusses how the Human Ecosystem Model (HEM) consolidates and restructures some of the systematic thought and action on human–nature transactions. Specifically, it outlines a framework for decisions that are effective, efficient, and equitable in sustaining human and biophysical ecology. Not surprisingly, professionals and concerned citizens have generated many differing perspectives on the nature of the problems, the theories about cause and consequence, and the methods for resolving the perceived issues. The HEM seeks to fit this scientific and experiential information into a more manageable and cumulative organizational frame. This frame reduces much of the information “noise” to some key variables and relations that guide crucial questions about patterns and processes of the human ecosystem.

This chapter illustrates how the application of the Human Ecosystem Model (HEM) has recently been extended to include science-based assessments during major environmental crises. The model has been used as a scenario-building tool during both the Deepwater Horizon oil spill (2010) in the Gulf of Mexico and Hurricane Sandy along the East Coast of the United States (2012). These extraordinary events—one originating in failures within the social system (government, technology, and industry, for example) and one originating in a historical natural event—offer robust tests of how the HEM can be used to improve decision-making, resource management, and policy. The chapter shows why the HEM was used in the scenario-building sessions: it includes both biophysical and socioeconomic elements, is explicit regarding flows, and has an emerging record of application.