Koji Kotani

Climatic impacts on crop yield and its variability in Nepal: do they vary across seasons and altitudes?

A rapid change in climate patterns potentially driven by global warming is considered to be greatest threats to agriculture. However, little is known about how the change in climate concretely affects agricultural production especially in Nepal with respect to seasons and regions of different altitudes. To examine this issue, we seek to empirically identify the impact of climatic variation on agricultural yield and its variability by utilizing the data of rice, wheat and climate variables in the central region of Nepal. The main focus is on whether the impacts vary across seasons, altitudes and the types of crops. For this purpose, we employ a stochastic production function approach by controlling a novel set of season-wise climatic and geographical variables. The result shows that an increase in the variance of both temperature and rainfall has adverse effects on crop productions in general. On the other hand, a change in the mean levels of the temperature and rainfall induces heterogeneous impacts, which can be considered beneficial, harmful or negligible, depending on the altitudes and the kinds of crops. These results imply that adaptation strategies must be tailor-made in Nepalese agriculture, considering growing seasons, altitudes and the types of crops.

Dynamic economic analysis on invasive species management: some policy implications of catchability.

The problem of controlling invasive species has emerged as a global issue. In response to invasive species threats, governments often propose eradication. This article challenges the eradication view by studying optimal strategies for controlling invasive species in a simple dynamic model. The analysis mainly focuses on deriving policy implications of catchability in a situation where a series of controlling actions incurs operational costs that derive from the fact that catchability depends on the current stock size of invasive species. We analytically demonstrate that the optimal policy changes drastically, depending on the sensitivity of catchability in response to a change in the stock size, as well as on the initial stock. If the sensitivity of catchability is sufficiently high, the constant escapement policy with some interior target level is optimal. In contrast, if the sensitivity of catchability is sufficiently low, there could exist a threshold of the initial stock which differentiates the optimal action between immediate eradication and giving-up without any control. In the intermediate range, immediate eradication, giving-up without any control, or more complex policies may be optimal. Numerical analysis is employed to present economic intuitions and insights in both analytically tractable and intractable cases.

Enhancing voluntary participation in community collaborative forest management: A case of Central Java, Indonesia *

This paper examines voluntary participation in community forest management, and characterizes how more participation may be induced. We implemented a survey of 571 respondents and conducted a case study in Central Java, Indonesia. The studys novelty lies in categorizing the degrees of participation into three levels and in identifying how socio-economic factors affect peoples participation at each level. The analysis finds that voluntary participation responds to key determinants, such as education and income, in a different direction, depending on each of the three levels. However, the publicly organized programs, such as information provision of benefit sharing, are effective, irrespective of the levels of participation. Overall, the results suggest a possibility of further success and corrective measures to enhance the participation in community forest management.

Optimal invasive species management under multiple uncertainties

The management programs for invasive species have been proposed and implemented in many regions of the world. However, practitioners and scientists have not reached a consensus on how to control them yet. One reason is the presence of various uncertainties associated with the management. To give some guidance on this issue, we characterize the optimal strategy by developing a dynamic model of invasive species management under uncertainties. In particular, focusing on (i) growth uncertainty and (ii) measurement uncertainty, we identify how these uncertainties affect optimal strategies and value functions. Our results suggest that a rise in growth uncertainty causes the optimal strategy to involve more restrained removals and the corresponding value function to shift up. Furthermore, we also find that a rise in measurement uncertainty affects optimal policies in a highly complex manner, but their corresponding value functions generally shift down as measurement uncertainty rises. Overall, a rise in growth uncertainty can be beneficial, while a rise in measurement uncertainty brings about an adverse effect, which implies the potential gain of precisely identifying the current stock size of invasive species.

Optimal risk management of human alveolar echinococcosis with vermifuge

In this study, we develop a bioeconomic model of human alveolar echinococcosis (HAE) and formulate the optimal strategies for managing the infection risks in humans by applying optimal control theory. The model has the following novel features: (i) the complex transmission cycle of HAE has been tractably incorporated into the framework of optimal control problems and (ii) the volume of vermifuge spreading to manage the risk is considered a control variable. With this model, we first obtain the stability conditions for the transmission dynamics under the condition of constant control. Second, we explicitly introduce a control variable of vermifuge spreading into the analysis by considering the associated control costs. In this optimal control problem, we have successfully derived a set of conditions for a bang-bang control and singular control, which are mainly characterized by the prevalence of infection in voles and foxes and the remaining time of control. The analytical results are demonstrated by numerical analysis and we discuss the effects of the parameter values on the optimal strategy and the transmission cycle. We find that when the prevalence of infection in foxes is low and the prevalence of infection in voles is sufficiently high, the optimal strategy is to expend no effort in vermifuge spreading.

Social value orientation and capitalism in societies

Cooperation and competition are core issues in various fields, since they are claimed to affect the evolution of human societies and ecological organizations. A long-standing debate has existed on how social behaviors and preferences are shaped with culture. Considering the economic environment as part of culture, this study examines whether the ongoing modernization of competitive societies, called “capitalism,” affects the evolution of people’s social preferences and behaviors. To test this argument, we implemented field experiments of social value orientation and surveys with 1002 respondents for three different areas of Bangladesh: (i) rural, (ii) transitional and (iii) capitalistic societies. The main result reveals that with the evolution from rural to capitalistic societies, people are likely to be less prosocial and more likely to be competitive. In a transitional society, there is a considerable proportion of “unidentified” people, neither proself nor prosocial, implying the potential existence of unstable states during a transformation period from rural to capitalistic societies. We also find that people become more proself with increasing age, education and number of children. These results suggest that important environmental, climate change or sustainability problems, which require cooperation rather than competition, will pose more danger as societies become capitalistic.

Invasive species management in two-patch environments: agricultural damage control in the raccoon (Procyon lotor) problem, Hokkaido, Japan

We develop discrete-time models for analyzing the long-run equilibrium outcomes on invasive species management in two-patch environments with migration. In particular, the focus is on a situation where removal operations for invasive species are implemented only in one patch (controlled patch). The new features of the model are that (1) asymmetry in density-dependent migration is considered, which may originate from impact of harvesting as well as heterogeneous habitat conditions, and (2) the effect of density-dependent catchability accounts for the fact that the required effort level to remove one individual may rise as the existing population decreases. The model is applied to agricultural damage control in the raccoon (Procyon lotor) problem that has occurred in Hokkaido, Japan. Numerical illustrations demonstrate that the long-run equilibrium outcomes largely depend on the degree of asymmetry in migration as well as the sensitivity of catchability in response to a change in the population size of the invasive species. Furthermore, we characterize the conditions under which the economically optimal effort levels are qualitatively affected by the above two factors, and conclude that aiming at local extermination of invasive species in the controlled patch is justified.

Intergenerational sustainability dilemma and the degree of capitalism in societies: a field experiment

Maintaining intergenerational sustainability is a minimum requirement for the existence of humankind, but it is now becoming one of the biggest challenges. Thus, it is necessary to understand what factors determine human preference and behavior for intergenerational sustainability. We hypothesize that ongoing modernization of competitive societies, which we call “capitalism,” affects individual social preferences and other factors of human nature, compromising intergenerational sustainability. To examine this hypothesis, we implement an intergenerational sustainability dilemma game with “imaginary future generation” (IFG) as a policy tool (to prime people for future generations) in two types of Bangladeshi fields: (1) urban (capitalistic) and (2) rural (less capitalistic) areas. The analysis reveals that the likelihood of choosing intergenerational sustainable options significantly increases with the number of prosocial people in one generation and a dummy variable of rural areas. Since a considerable portion of people in rural areas are prosocial, rural people are identified to choose intergenerational sustainable options much more frequently than urban people. Moreover, the IFG treatment is not effective for urban people, implying that some stronger devices shall be necessary in capitalistic societies. Overall, our findings demonstrate that as societies become more capitalistic, intergenerational sustainability shall be further compromised through the change in people’s social preferences and area-specific effects.

Optimal escapement levels on renewable resource management under process uncertainty: some implications of convex unit harvest cost

The terminology of renewable resource management spans not only prototype harvesting problems but also various new types such as invasive species problems. In all of these problems, process uncertainty of stock growth associated with environmental variability is one of the critical factors that significantly affects the management efficiency. While it may seem that a series of past research has fully examined optimal policy under process uncertainty, the case of convex unit harvest costs has not been fully characterized yet. Focusing on such a case, this article addresses how the degree of process uncertainty affects optimal escapement level. The result suggests that optimal escapement level does not monotonically vary with process uncertainty. In many plausible cases, it should be adapted in a U-shaped manner, which is in contrast with conventional wisdom.

Sustainability of common pool resources

Sustainability has become a key issue in managing natural resources together with growing concerns for capitalism, environmental and resource problems. We hypothesize that the ongoing modernization of competitive societies, which we refer to as “capitalism,” affects human nature for utilizing common pool resources, thus compromising sustainability. To test this hypothesis, we design and implement a set of dynamic common pool resource games and experiments in the following two types of Nepalese areas: (i) rural (non-capitalistic) and (ii) urban (capitalistic) areas. We find that a proportion of prosocial individuals in urban areas is lower than that in rural areas, and urban residents deplete resources more quickly than rural residents. The composition of proself and prosocial individuals in a group and the degree of capitalism are crucial in that an increase in prosocial members in a group and the rural dummy positively affect resource sustainability by 65% and 63%, respectively. Overall, this paper shows that when societies move toward more capitalistic environments, the sustainability of common pool resources tends to decrease with the changes in individual preferences, social norms, customs and views to others through human interactions. This result implies that individuals may be losing their coordination abilities for social dilemmas of resource sustainability in capitalistic societies.