Detection of biotic responses to urbanization using fish assemblages from small streams of western Georgia,USA

We examined relationships between stream fish assemblages and land use alteration associated with urbanization in 15 lower Piedmont watersheds along an urbanization gradient north of Columbus, western Georgia. Based on land cover data from 2002 Landsat 7 TM imagery aerial photos, streams drained watersheds that were largely urban, developing (suburban), agricultural (pasture), managed pine forest, and unmanaged mixed-forest. We quantified fish seasonally from 3 run-pool segments in each stream, and used a variety of metrics as response variables in analyses of relationships between fish assemblage structure and land use and natural basin variation. In general, Georgia-Index of Biotic Integrity (GA-IBI) values, Bray-Curtis faunal similarity of streams to mean conditions within reference streams, proportions of fish as lithophilic spawners, and fish lacking eroded fins, lesions, tumors decreased with increasing urbanization. Multiple regression indicated that assemblages were explained by a combination of land use and natural basin variables (basin size, average discharge, nearest distance to a larger downstream tributary [colonization source]), with land use variables being important predictors of summer assemblages and natural basin variables being more important in winter and spring assemblages. Non-metric multidimensional scaling (NMDS) ordinations revealed strong separation between assemblages in urban watersheds and forested watersheds, whereas assemblages in agricultural and developing watersheds were intermediate between those in urban and forested watersheds. Our data suggest that fish are reliable indicators of anthropogenic disturbance at the landscape scale, at least seasonally, and may be used to forecast the magnitude of landscape-level changes in stream structure and function associated with the conversion of forests to urban/suburban land in the Southeast.     

American Young Adults’ Rural-to-Urban Migration and Timing of Exits from Poverty Spells

This study examined the timing of exit from poverty among rural young adults who migrated to urban areas in the United States, using the National Longitudinal Survey of Youth 1979, with a focus on gender and marital status. Poverty spells that involved relocation to urban areas lasted longer than those that did not. Poverty exit rates upon relocation to urban areas declined each year the young adults remained in poverty, but the impact remaining in urban areas had on reduced poverty exit rates diminished when family characteristics, human capital, and labor market factors were controlled.This research was supported by the United States Department of Agricultural through the Georgia Agricultural Experiment Station and also by the Jagdish N. Sheth Foundations Association for Consumer Research Public-Purpose Dissertation Award. An earlier version of this paper was prepared for a presentation at the Population Association of America Annual Meeting 2001, Washington DC. We thank Deborah Godwin and anonymous reviewers for helpful comments and Karen Braxley for editorial assistance and insightful comments.     

Transportation Hardship: Are You Better off with a Car?

Growing evidence demonstrates the importance of transportation in improving family economic well being. This article sheds light on the hardship that one important transportation asset, private vehicles, may exert on families. Data from the Iowa Transportation and Employment Survey provided a unique opportunity to understand how vehicle access enables households to meet their basic needs, but may exacerbate their problems through the creation of additional demands on resources. Approximately 26% of the sample reported having experienced transportation hardship. The strongest predictors of transportation hardship were the presence of children in the household, low income, driving less reliable vehicles, and the unavailability of transportation assistance from someone outside the household. How to help families meet their transportation needs in light of this evidence remains open to debate.     

Live-in Foreign Domestic Workers and their Impact on Hong Kong’s Middle Class Families

This paper discusses the impact of foreign domestic workers (FDWs) on parental roles and family dynamics of Hong Kong’s middle class families. The increase in married women’s labor force participation in Hong Kong has led to a greater demand for childcare, which has been filled by FDWs. Based on interviews with 15 dual-earner couples in middle class nuclear families employing FDWs, how FDWs affect the mother’s gender role and family dynamics is discussed. Boundary work is used by parents in their daily interaction with their children and their FDWs so as to reconcile the perceived indispensability of these workers on the one hand, and the challenges they pose to the definition of parenthood on the other. This research was funded by a Lingnan University Social Sciences Program Research Grant RES/SOC010/978. I am grateful to the guest editors and two anonymous reviewers for their valuable comments.     

Career Planning in Spain: Do Fixed-term Contracts Delay Marriage and Parenthood?

The aim of this paper is to find an empirical connection between the striking increase in the use of fixed-term contracts in Spain and the observed delay in the age at marriage and maternity. Using the eight waves of individual information from the European Household Panel for Spain, we find that for men, the decision whether to get married is strongly negatively affected by holding unstable contracts or not working, relative to when an indefinite contract is held. However, for women, results suggest that holding fixed-term contracts is not a deterrent for the decision whether to get married. With respect to the decision of whether to enter into parenthood, results indicate that for all childless women, either with no partner, holding fixed-term contracts delays entry into motherhood relative to the holding of indefinite contracts. The discouragement effect is stronger for women with no partner, though.JEL classification: D1, J1     

“The Motherhood Wage Gap for Women in the United States: The Importance of College and Fertility Delay”

One of the stylized facts from the past 30 years has been the declining rate of first births before age 30 for all women and the increase rate of first births after age 30 among women with four-year college degrees (Steven P. Martin, Demography, 37(4), 523–533, 2000). What are some of the factors behind womens decision to postpone their childbearing? We hypothesize that the wage difference often observed between like-educated mothers and non-mothers (Jane Waldfogel, Journal of Labor Economics, 16, 505–545, 1998a; Journal of Economic Perspectives 12(1) 137–156, 1998b) may be affected by the postponement of childbearing until after careers are fully established. Hence, we focus on college-educated women because they are typically more career-oriented than their non-college educated counterparts and also the group most often observed postponing maternity. We use individual-level data on women from the 1979 National Longitudinal Survey of Youth (NLSY79) in order to control for individual-level unobserved heterogeneity as well as human capital characteristics, such as actual work experience, in our empirical analysis. We estimate wage equations, first producing base-line results to compare to the existing literature. Then, we expand the basic wage equation model to address fundamental econometric issues and the education/fertility issue at hand. Our empirical findings are two-fold. First, we find that college-educated mothers do not experience a motherhood wage penalty at all. In fact, they enjoy a wage boost when compared to college-educated childless women. Second, fertility delay enhances this wage boost even further. Our results provide an explanation for the observed postponement of maternity for educated women. We argue that the wage boost experienced by college-educated mothers may be the result of their search for family–friendly work environments, which, in turn, yields job matches with more female-friendly firms offering greater opportunities for advancement.JEL Codes: J13 and J3     

The Effect of a Family Policy Reform on Mother’s Pay: A Natural Experiment Approach

All parents in Norway with children aged one to three, who do not attend publicly subsidised day care, are entitled to a cash-for-care (CFC) subsidy. Studies have shown that the reform has reduced mothers labour supply. In this paper we analyse wage effects of the reform. We put forward a framework for evaluating reforms when reforms are uniformly and equally accessible nation-wide. First, running a simple Difference in differences (DD) analysis, results suggest that the CFC reform has reduced the mothers wages. However, after controlling for the age of the child effect, by running a triple difference approach, we no longer find any evidence of negative wage effects.This revised version was published online in May 2005 with corrections to the authors name and to the heading of table A2.     

“Economic Theory’s Stance On No-Fault Divorce”

This article explores key insights that economic theory can shed on the issue of no-fault divorce in the United States, addressing modifications in the incentive structure of individuals that resulted from the legislative reforms of the 1970s. After stressing the importance of correctly interpreting and classifying divorce laws, this work investigates the contributions of the theory of property rights, the contributions of game theory and intra-household bargaining, and the contributions of general equilibrium analysis in our understanding of how divorce laws work and what their impact is. By doing so, this exposé analyzes the theoretical consequences of no-fault divorce on the decision whether to get married or divorced, on the characteristics of spouses and divorcees, on divorce rates, and on marital-specific and non marital-specific investments.