Selecting species for restoration in foundational assemblages

Humans have long sought to restore species but little attention has been directed at how best to do so for rich assemblages of foundation species that support ecosystems, like rainforests and coral reefs that are increasingly threatened by environmental change. We developed a two-part triage process for selecting optimized sets of species for restoration. We demonstrated this process using phenotypic traits and ecological characteristics for reef building corals found along the east coast of Australia. Without clear linkages between phenotypic traits and ecosystem functions, the first part of the triage hedges against function loss by ensuring an even spread of life history traits. The second part hedges against future species losses by weighting species based on characteristics that are known to increase their ecological persistence to current environmental pressures--abundance, species range and thermal bleaching tolerance--as well as their amenability to restoration methods. We identified sets of ecologically persistent and restorable species most likely to protect against functional loss by examining marginal returns in occupancy of phenotypic trait space per restored species. We also compared sets of species with those from the southern-most accretional reef as well as a coral restoration program to demonstrate how trait space occupancy is likely to protect against local loss of ecosystem function. Synthesis and applications. A quantitative approach to selecting sets of foundational species for restoration can inform decisions about ecosystem protection to guide and optimize future restoration efforts. The approach addresses the need to insure against unpredictable losses of ecosystem functions by investing in a wide range of phenotypes. Furthermore, the flexibility of the approach enables the functional goals of restoration to vary depending on environmental context, stakeholder values, and the spatial and temporal scales at which meaningful impacts can be achieved.

Returns to Farming

This chapter describes problems associated with marginal returns analysis and the form taken by the Cobb-Douglas production function. It goes on to compare the returns to production of bush- and village-field millet, for 1980 and 1981, and discusses the wide divergence in returns between crops within and between years. This is followed by comparison of returns to different factors of production with the prices at which these are occasionally available, before reviewing the reasons for some farmers showing markedly different returns from the average.

Millet-Production Analysis

Analysis of millet-production shows the size and variability of returns to different farm inputs, for each of the millet varieties. Regression analysis is based on the Cobb-Douglas production function, to generate a set of marginal returns to factors between uses, from one year to the next and between farmers. Farmers make decisions based on past experience and in a context of uncertainty about the future. The principal inputs are described for analysis of village-field and bush-field millet varieties, their measurement and representation in regression equations. Results from the analysis are presented to show the relative significance of each factor, and the high levels for R2 associated with manure use, plough-team use, and the soil dummy variable. The labour variable was more problematic. Analysis of the residual error term permitted a review of each farming household, difficulties in accurately measuring particular variables, and significant differences in farmers’ knowledge, aptitude and judgement.

Fixed Investment and Economic Growth: ARDL and Causality Exploration for SADC Countries

In assessing the short run and the long-run effects of fixed investment and economic growth among Southern Africa countries, we evaluated the economic progress of the SADC (Southern African Development Committee) region. Our objective is to determine how variables (GDP, purchasing power parity, inflation, electricity, balance-of-payments, and unemployment) can be affected by the fixed investment. In determining how fixed investment affects economic activities and policies among the states, the ADRL estimation approach is applied. Using data from 13 countries in the SADC region from the period 1992-2018, we enumerate the variables’ marginal returns against the fixed investment component. The results of diagnostic and other tests show that all statistical procedures are robust. The result proves that the benefits of fixed investment are yielded over a long period rather than short periods. As a result, the cost in the short term cannot be compared to the benefits that will be enjoyed later by an economy as it becomes productive. Furthermore, the lack of consistent fixed investment among countries will eventually lead to insufficient cash flow, which will negatively affect the currency. These results would seem to suggest that the introduction of policies that promote investment will massively contribute to increased productivity and positive economic growth in the region.

Provisioning an Early City: Spatial Equilibrium in the Agricultural Economy at Angkor, Cambodia

A dominant view in economic anthropology is that farmers must overcome decreasing marginal returns in the process of intensification. However, it is difficult to reconcile this view with the emergence of urban systems, which require substantial increases in labor productivity to support a growing non-farming population. This quandary is starkly posed by the rise of Angkor (Cambodia, 9th–fourteenth centuries CE), one of the most extensive preindustrial cities yet documented through archaeology. Here, we leverage extensive documentation of the Greater Angkor Region to illustrate how the social and spatial organization of agricultural production contributed to its food system. First, we find evidence for supra-household-level organization that generated increasing returns to farming labor. Second, we find spatial patterns which indicate that land-use choices took transportation costs to the urban core into account. These patterns suggest agricultural production at Angkor was organized in ways that are more similar to other forms of urban production than to a smallholder system.

Effects of insecticides and cultivars on panicle-feeding insect pest infestations and grain yield of sorghum (Sorghum bicolor (L.) Moench) in northern Ghana

Background Panicle-feeding insects are a challenge in sorghum (Sorghum bicolor (L.) Moench) cultivation but most farmers do not protect the crop. Here, the effects of pest management in different sorghum cultivars on grain yields and the financial returns after protecting the crop from panicle-feeding insects was studied. Results There were significant insecticide treatments × cultivars/genotypes interaction effects for Stenodiplosis sorghicola, Clavigralla tomentosicollis, Nezara viridula, Dysdercus fasciantus and Riptortus dentipes. Generally, pest infestations were higher in the untreated control compared to K-Optimal- or NSO-treated sorghum. Infestations were also higher in compact-headed cultivars (Dorado and Kapaala) compared to those with open heads (CSSOR 08-V01 and CSSOR 10-V07). Damage was approximately 1.7-fold higher in the untreated controls than in NSO or K-Optimal. Grain yields were about 14% higher in NSO or K-Optimal treated sorghum than in controls. Gross margins were between 16- and 35-fold higher in protected sorghum compared to the untreated ones. Conclusion These findings suggest that an effective integrated pest management strategy for sorghum farmers must comprise cultivars that do not have compact heads, and the use of about two sprays of NSO or a synthetic pyrethroid when high numbers of panicle-feeding insects are observed during the growing season. Judicious use of insecticides and the “right” cultivar will improve the profitability of sorghum farmers with gross marginal returns that are at least 15-fold higher than that obtained by farmers who adopt only good agronomic practices without insecticide sprays.

The Wealth Effect of Corporate Water Actions: How Past Corporate Responsibility and Irresponsibility Influence Stock Market Reactions

Ensuring access to clean water is one of the most important development and health challenges of the twenty-first century. Given the manifold impacts of business activities on water resources, corporate water actions should be of central concern to business ethics researchers. Yet so far we know too little about whether business activities that impact on water resources are noticed or how corporate water actions are valued by a firm’s stakeholders, including by financial markets. In response, we conduct an event study to investigate the shareholder wealth effect of reports of corporate water actions. We explore stock market reactions to water actions by S&P 500 firms from 2005 to 2017, showing that the market reacts positively to reports of responsible water actions and negatively to irresponsible actions. We further explain that these abnormal returns to water actions are associated with a firm’s past performance on ethical issues, arguing that the reputational effects from prior corporate social responsibility and irresponsibility influence market reactions. Our analysis provides evidence that there are diminishing marginal returns to responsible water actions for firms with records of past responsibility and an offsetting effect for those with past irresponsibility. Similarly, we demonstrate an insurance effect that limits punishment for irresponsible water actions for firms with responsible performance records and diminishing negative marginal returns for those already seen to be irresponsible. This study is the first to show that shareholders recognize market value in corporate water actions and are prepared to award or punish firms in stock markets based on their impacts on water.

Optimal Interval Division

This paper provides a simple unified analysis of optimal interval division problems. My primitive is a cell function that assigns a value to each subinterval (cell). Submodular cell functions conveniently imply the property of decreasing marginal returns. Also, for coarse decision problems, optimal cutoffs commonly increase as prior belief shifts upward. Its implications on language and efficient menus are discussed.

Using metabolic energy to quantify the subjective value of physical effort

Economists have known for centuries that to understand an individual's decisions, we must consider not only the objective value of the goal at stake, but its subjective value as well. However, achieving that goal ultimately requires expenditure of effort. Surprisingly, despite the ubiquitous role of effort in decision-making and movement, we currently do not understand how effort is subjectively valued in daily movements. Part of the difficulty arises from the lack of an objective measure of effort. Here, we use a physiological approach to address this knowledge gap. We quantified objective effort costs by measuring metabolic cost via expired gas analysis as participants performed a reaching task against increasing resistance. We then used neuroeconomic methods to quantify each individual's subjective valuation of effort. Rather than the diminishing sensitivity observed in reward valuation, effort was valued objectively, on average. This is significantly less than the near-quadratic sensitivity to effort observed previously in force-based motor tasks. Moreover, there was significant inter-individual variability with many participants undervaluing or overvaluing effort. These findings demonstrate that in contrast with monetary decisions in which subjective value exhibits diminishing marginal returns, effort costs are valued more objectively in low-effort reaching movements common in daily life.

Social Investment, Employment and Policy and Institutional Complementarities: A Comparative Analysis across 26 OECD Countries

Raising employment has been at the heart of EU strategies for over twenty years. Social investment, by now a widely debated topic in the comparative welfare state literature, has been suggested as a way to pursue this. However, there are only a couple of systematic comparative analyses that focus on the employment outcomes associated with social investment. Analyses of the interdependence of these policies with regard to their outcomes are even more scarce. We empirically analyse the extent to which variation in employment rates within 26 OECD countries over the period 1990-2010 can be explained by effort on five social investment policies. We additionally explore the role of policy and institutional complementarities. Using time-series cross-section analyses we find robust evidence for a positive association between effort on ALMPs and employment rates. For other policies we obtain mixed results. ALMPs are the only policies for which we observe signs of policy interdependence, which point at diminishing marginal returns. Additionally, our analysis demonstrates that the interdependence of social investment policies varies across welfare state regimes. Together, this indicates that the employment outcomes of social investment policies are also contingent on the broader framework of welfare state policies and institutions.