Douglas M. Johnston

Creating multifunctional landscapes: how can the field of ecology inform the design of the landscape?

The opportunity exists to improve intensively managed landscapes (urban and agricultural areas dominated by human activities) through greater engagement of ecologists in the process of ecological landscape design. This approach encourages exploration of multifunctional solutions to meet the needs of growing populations in many areas around the world, while minimizing the negative impacts of human activities on the environment. This is achieved by incorporating theoretical and applied principles from the fields of landscape ecology, agroecology, and ecological design. Multifunctional landscapes can be designed to provide a range of environmental, social, and economic functions, while considering the interests of landowners and users. Here, we propose a process for designing multifunctional landscapes, guided by ecological principles in the following steps: (1) defining the project site and landscape context, (2) analyzing landscape structure and function, (3) master planning using an ecosystem approach, (4...

Designing Landscapes for Performance Based on Emerging Principles in Landscape Ecology

We have proposed a framework for transforming landscapes to improve performance by integrating ecological principles into landscape design. This effort would focus on the development of multifunctional landscapes, guided by the rapidly growing knowledge base of ecosystem services provided by landscape features. Although the conventional approach to landscape ecology is based on a model that assumes poor ecological quality in the human-dominated matrix, a review of recent literature reveals important opportunities to improve the quality of the landscape matrix by increasing spatial heterogeneity through the addition of seminatural landscape elements designed to provide multiple ecosystem services. Taken alone, these individual elements might not appear to have a large impact on the environment, but when considered together within the entire landscape, the contribution could be significant, particularly when these elements are intentionally designed to improve landscape performance. Previous attention has focused on the value of large patches of native vegetation for conservation efforts. These efforts have included preserving those areas that still remain, restoring those that once existed, and providing connectivity between them. But great opportunities exist to improve the quality of the matrix by designing multifunctional elements throughout the landscape. Through a synthesis of knowledge in landscape architecture and landscape ecology, we have demonstrated some important applications of the landscape performance framework in urban and agricultural settings. Based on a review of the literature, we have suggested several methods of evaluating and monitoring landscape performance to determine the relative success of a designed landscape.

Channelization and levee construction in Illinois: Review and implications for management

The environmental impact of loss of natural stream and riparian habitat is of concern throughout the United States and Europe. Environmental impacts related to such activities as channelization of and levee construction along streams and rivers are particularly apparent in the Midwestern United States. The objective of the research presented here was to delineate the extent, relative degree of impact, and implications for management of channelization and levee construction along watercourses located in the state of Illinois. According to records maintained through the Illinois Streams Information System data base (Illinois Department of Conservation), nearly 25% of surface water resources in the state have been modified directly by channelization and/or levee construction. Reviews of agency records, elaboration of case histories, interviews with agency personnel, and inspections of impacted sites indicated that these alterations have occurred without the benefit of effective mitigation. Although permit records may provide suggestions for mitigation to be incorporated in the design of a particular project, permits issued generally do not require even minimal instream habitat and bank stabilization efforts in conjunction with channel alteration. Information derived from policy and case study analyses suggests that institutional constraints, rather than lack of particular understanding about mitigation, provide major barriers to protecting the states surface water resources in terms of regulatory review, policy interpretation and implementation, and project evaluation. Recommendations for environmental management efforts regarding these and similar channel alterations are elaborated from these findings.

Analysis of naturalization alternatives for the recovery of moist-soil plants in the floodplain of the Illinois River

The hydrologic regime of the Illinois River has been substantially altered by floodplain levees, navigation dams, and water diversion. Unnaturally frequent and untimely water level fluctuations, large and small, have decreased the productivity of many floodplain vegetation communities that provide important ecological services, including the moist-soil plant community. We simulated three scenarios, including two that were expected to benefit moist-soil plants: (1) existing conditions, with levees and navigation dams closed during the summer growing season; (2) levees opened to reconnect the river and its floodplain during the growing season; and (3) both the downstream navigation dam and the levees opened during the growing season. A 1-dimensional hydraulic model generated daily hydrographs of the river at three positions in the 135 km study reach: (1) near the downstream dam, (2) in the middle of the reach, and (3) near the upstream dam. These hydrographs then were used to run a model that predicts the growth of moist-soil plants at a range of floodplain elevations. As expected, the model predicted that plants would grow over a larger area with levees open during the growing season than under the existing conditions, but the outcomes showed a strong location dependency. Moist-soil plant production would increase in the upper and mid-reach locations, but there would be no change near the downstream dam despite opening the levees. Modelling revealed that the existing operation of the navigation dam permanently floods most of the floodplain zone where moist soil plants might grow for at least 15 km upstream of the dam. Trees currently grow all the way to the low water line and are likely to exclude moist soil plants from any restored portion of the floodplain. Sites for reconnecting the river with its floodplain should be carefully chosen to maximize the chances of recovering the important moist-soil plant community in this regulated river.

Application of fuzzy decision making: An evaluation

Abstract Many decisions require the application of subjective judgment. Two methods of modelling such decision behaviour by using fuzzy set theory are considered here. Yager (1 978) uses a method based on a maximin criterion, while Tsukamoto and Terano (1975) base their method on multivalued logic operations. In this paper sets of decision makers evaluation of decision problems are compared with each of the two fuzzy set evaluations. The ability of the fuzzy set methods to replicate decision behaviour is measured by the rank correlation between orderings of alternatives obtained from the decision makers and those obtained from the. methods. Analysis of the experiment indicated that for the sample used, the methods generated very few correlations that were significantly greater than zero. These results appear to contradict claims for the methods made in the literature.

Qualitative Spatial Representation for Situational Awareness and Spatial Decision Support

This paper summarizes elements of research on the effectiveness of using qualitative spatial representation (QSR) in 2D and 3D display modes to determine its usefulness for situational awareness and decision making. The study involved: 1) creating spatial query functions based on QSR that capture knowledge about objects in space; 2) building these query functions into a graphical user interface environment as simulated user accessible support functions; and 3) testing the utility of these support functions by evaluating the performance of human subjects in solving sets of spatial decision-making and information retrieval tasks.

Green Landscapes: Exogenous Economic Benefi ts of Environmental Improvement

A past study of the landscape architecture profession and resulting marketing strategy emphasized the value added by design services (Bookout 1994). It supported the notion that design was not necessarily a luxury, a loss-leader, or other marginal(ized) component of the built environment, but had real value. Nonetheless, the marketing still smacked of triviality – the notion that landscape architectural contributions were something akin to an “after-market” product of land development rather than a fundamental element of the building process. We argue here that the benefits of environmental improvement through mitigation and prevention form a more core component of land-use decision-making. The environment provides numerous goods and services to communities. Of course it provides life-sustaining elements for food, air, water. It provides raw materials for production of other goods and services. It also provides regulation of ecological processes, habitat, recreation, identity, pleasure, and many other tangible and less-tangible benefits. Variations in the quality of environmental goods and services quite logically lead to variations in their potential valuation. The production of particular qualities and quantities of environmental goods and services falls well within the scope of the design and planning professions. As such, they act as agents of landscape change in both direct (the construction of particular places, in particular ways) and less direct ways (through the generation of economic – among other – benefits). A proper accounting for the benefits of particular landscape goods and services can lead to different decisions about the provision of those goods and services, affecting the future state of the landscape. There are numerous challenges to examining the benefits associated with environmental change. A major challenge is that many of the potential benefits must be imputed from other measures, as they are not directly accounted for in the marketplace. The indirect accounting is due to several factors, but of particular interest here is the classic problem of public goods. The landscape, in addition to being a source of resources, is also used as a sink for waste products. When a pollutant is added to the environment, the benefits (the avoidance of treating or eliminating the pollutant) accrue to the entity that produced the pollutant. However, the costs, in terms of environmental degradation, are borne by entities not receiving the benefits (such as downstream or downwind residents).

Discussion of papers

In considering reforms in the nations system of welfare assistance to low-income families, a negative income tax plan that covers intact (husband-wife) families had been expected to increase marital stability relative to the existing system of Aid to Families with Dependent Children, which basically denies welfare assistance to families with a father present. Between 1977 and 1983, however, a series of research papers reported that the negative income tax plans in the Seattle-Denver Income Maintenance Experiment increased marital dissolutions. This finding and research challenged existing beliefs among economists and had a great influence in public policy debates about welfare reform and in research methodology in the social sciences. In our analysis we claim to refute the major conclusion from this research: We find no effect of practical significance of the negative income tax on the rate of marital breakups when comparing treatment and control families in the experiment. We use and extend the statistical techniques of event history analysis that were pioneeringly adopted in the original research. Simple economic ideas motivate our analysis and interpretations. Although we believe we have resolved the major puzzle created by the original finding of a destabilizing effect on marriage, there remain challenges to an economic explanation for other experimental outcomes, such as the surprising result that marital breakups are less likely to occur the larger are the expected payments that the wife would receive if she separated from her husband. This discussion paper differs from our previous paper DP 857-88 in two respects. (a) This paper focuses on the economic model underlying the relation of income maintenance laws and marital stability and estimates models with close attention to the economic components of the incentives in the laws. (b) This paper does not give a detailed examination of the previous research about marital outcomes in the Seattle-Denver experiment. See DP 857-88 for a discussion of why our results differ from those of the original researchers. Marital Breakups in the Seattle-Denver Income Maintenance Experiment: A Different Conclusion Quotations from Hearings, Subcommittee on Public Assistance of the Committee on Finance, 95th Congress, 2d Session, November 15-17, 1978. Dr. Jodie Allen, Department of Labor: ...there are reasons to think that the [behavioral effects of the] experiments, particularly the marital stability findings, are higher relative to what you would find even if extrapolated to more modest programs .... 1 think it is important to remember that what was observed are marginal influencesn (p. 26). Senator Daniel P. Moynihan: A 60 percent increase over the control group where there is a lot bf marital breakups] to begin with-is that marginal, maam? (P. 26). Moynihan: If it turned out that we have a program [for income maintenance] that reduced work effort by 3.2 hours per week among white males, I think the world would go on and it would not be any great disaster. But breaking up families is a large eventn (p. 289). THE PUZZLE AND T H E CHALLENGE Most of the attention in the economic journals that was given to the negative income tax (NIT) experiments that took place between 1968 and 1981 was devoted to the issue of labor supply response Among all the behavioral outcomes of the experiment, however, the findings about marital stability had the largest political impact; specifically. the findirtg that the NIT plans caused an increase in marital Citations to descriptions of the fou r experiments in negative income taxation and an extensive bibliography are found in .Moffitt and Kehrer (1981.). breakups relative to the existing program, Aid to Families with Dependent Children (AFDC) . This was the startling conclusion from the Seattle-Denver Income Maintenance Experiment (SIME-DIME), reported in a series of articles between 1977 and 1983 by three sociologists, Lyle Groeneveld, Michael Hannan, and Kancy T ~ m a . ~ SIME-DIME was the last and largest of four NIT field experiments, and its conclusions on marital stability have dominated all discussions of the experimental results on this subject. For reasons discussed below, this result was the opposite of what was expected by economists and of what was hoped for by advocates of the NIT. The political damage to legislative proposals for NIT-like reforms in the welfare system was immediate and long-la~ting.~ This experimental outcome has received little attention from economist^.^ In fact, no dissenting investigation of the research results has appeared in the social science literature from the time of the first published report (Hannan. Tuma, and Groeneveld. 1977). One obstacle to reanalyzing the experimental data from SIME-DIME is the complicated design of the experiment. Despite random assignments of low-income families to treatment and control groups, a number of features, discussed below, complicate the analysis. Also, the statistical techniques of hazard models and event Citations to over 20 articles and papers by these authors appear in the final report (Groeneveld, Hannan, and Tuma, 1983). 31n addition to the Congressional Hearings quoted a t the beginning of this paper, see Steiner (1981, pp. 100-112) and Lynn and Whitman (1981, pp. 247-249) for a discussion of the policy impact of the experimental findings on marital breakups. Recent citations of these experimental results as evidence for opposing welfare reforms that provide income support to husband-wife families are found in Lenkowsky (1986, p. 182) and Murray (1984, pp. 124-125, 157-166). 4 T ~ ~ exceptions are Bishop (1980) and Keeley (1987), but both accepted and reinforced the conclusions reached by Groeneveld, Hannan, and Tuma. history analysis that were used by Groeneveld, Hannan, and Tuma were unfamiliar to most economists when the research first appeared, but this is no longer true. A good reason for economists to be interested in the experimental research about marital stability is the prevailing belief that the economic incentives of AFDC have increased marital instability and the number of families headed by single mothers. AFDC provides cash payments and other benefits to a mother with dependent children if the father is absent but not, with infrequent exceptions, if the father is present. Economists have been prominent among advocates for welfare reforms, especially an NIT, which had been, until 1977, favorably viewed as a way of neutralizing the anti-marriage incentives of AFDC. Furthermore, although most research on marriage, including the experimental research: has been conducted by sociologists, the conclusion of Groeneveld, Hannan, and Tuma that an NIT increases marital breakups rested mainly on an economic theoretical framework. In this paper we reanalyze the data from SIME-DIME and claim to refute this conclusion. We find no effect of practical significance of the NIT plan on the rate of marital breakups. We use simple economic ideas to justify our analysis and interpretations, but some of our results seem inconsistent with straightforward economic hypotheses. Thus, although we believe we have resolved the major puzzle created by the original finding of the NITS destabilizing effect on marriages (relative to AFDC), there remain challenges to an economic explanation for other experimental outcomes. Kiefer (1988) gives an extensive bibliography of recent economic research that uses these statistical techniques. AFDC-UP. with UP standing for uunemployed parent, is an optional program offering AFDC to poor married couples whose principal earner is unemployed. Now adopted by about half the states, the program nevertheless has a very small number of couples participating. . COMPARING A F D C AND N I T IN THEIR EFFECTS ON MARITAL STABILITY General considerations. Equation (1) shows a simplified prototype of an AFDC income maintenance plan in effect during the 1970s when SIME-DIME was being conducted. Let AFDC(n) be the transfer payments received by a family of size n, composed of a mother and dependent children; let G(n) be the governments guaranteed level of transfer payments granted to the family if it has no other income; and let Y be the income the family receives (during the time period relevant for the AFDC payments) from its own earnings or from other private sources: such as child-support payments. In the 1970s an offset rate (or tax) of .67 per dollar of Y was in effect that reduced the transfer payments for the AFDC mother with other income. The plan may be expressed: for Y < Yb = G(n)/.67, with Yb as the breakeven level of income, where the AFDC payments decline to zero. In reality, the AFDC plan was (and is) more complicated, involving tests for eligibility depending on asset ownership, integration with other government welfare programs, the ages and school attendance of children, varying tax rates for certain types of nonlabor earnings, consideration of special circumstances to allow higher (or lower) payments, possible deductions of certain expenses of working from the earnings (Y) used to calculate AFDC payments, and other regulations. Nevertheless, the dominant consideration about AFDC in terms of its relation to marital status is that the program covered poor mothers with no husband present, whereas poor husband-wife families were and are not covered, with some unimportant exceptions. The economic argument for why AFDC is expected to destabilize marriages is simply that it lowers the cost of a marital breakup, particularly to poor husband-wife families with children. It lowers the cost to the mother, who is assumed to retain custody of the children and to have low alternative earnings, and it lowers the cost to the father, who may be unable or unwilling to make adequate child-support payments. AFDC is decidedly nonneutral regarding marital status. An NIT program, such as those in SIME-DIME, provides an income maintenance p