Explore the vast range of titles available.

Poor people derive most of their income from work; however, there is insufficient understanding of the role of employment and earnings as a linkage between growth and poverty reduction, especially in low income countries. With the objective of providing inputs into the policy discussion on how to enhance poverty reduction through increased employment and earnings for given growth levels, this study explores this linkage in the case of Madagascar using data from the national accounts and household surveys from the years 1999, 2001, and 2005, a period characterized among others by a short but severe crisis which started at the end of 2001 and the subsequent economic rebound. This report is part of a series of studies conducted in the context of the World Bank’s research framework aiming to improve the understanding of the linkages among growth, labor, and poverty reduction.

Multiple species show significant trait shifts in response to urbanization. Yet, the impact of anthropogenic warming linked to the urban heat island effect is remarkably understudied. In addition, the relative contributions of phenotypic plasticity and genetic change underlying trait shifts in response to urbanization are poorly known. A common garden study with the water flea Daphnia magna revealed that both genetic differentiation in response to urbanization and phenotypic plasticity in response to higher rearing temperature (24°C) induced significant parallel multivariate shifts in life‐history strategy along the slow–fast pace‐of‐life axis. Urban animals and animals reared at higher temperatures are characterized by fast maturation, early release of progeny, a smaller size at maturity, increased fecundity and higher performance (given by maximal population growth rate “r”) compared to genotypes isolated from rural ponds and animals reared at lower temperatures, respectively. Evolution in response to urbanization accounted for 30% of the total observed shift in life history and caused a significant change in mean trait values, while plasticity responses to experimental warming were unaltered between urban and rural populations. The total trait change achieved through both plasticity and evolution ranged from 8% to 56% depending on the trait. Our results provide clear evidence for evolution underlying an increase in pace of life of populations in response to urbanization. Given the pivotal role of Daphnia in aquatic ecosystems, this shift potentially feeds back to population structure, top‐down control of algae and food web dynamics in urban freshwater ecosystems. In addition, we argue that adaptation to urban heat islands might render these populations preadapted in a context of future climate change. plain language summary is available for this article. Plain Language Summary

Significance Forecasting reservoirs of zoonotic disease is a pressing public health priority. We apply machine learning to datasets describing the biological, ecological, and life history traits of rodents, which collectively carry a disproportionate number of zoonotic pathogens. We identify particular rodent species predicted to be novel zoonotic reservoirs and geographic regions from which new emerging pathogens are most likely to arise. We also describe trait profiles—complexes of biological features—that distinguish reservoirs from nonreservoirs. Generally, the most permissive rodent reservoirs display a fast-paced life history strategy, maximizing near-term fitness by having many altricial young that begin reproduction early and reproduce frequently. These findings may constitute an important lead in guiding the search for novel disease reservoirs in the wild. The increasing frequency of zoonotic disease events underscores a need to develop forecasting tools toward a more preemptive approach to outbreak investigation. We apply machine learning to data describing the traits and zoonotic pathogen diversity of the most speciose group of mammals, the rodents, which also comprise a disproportionate number of zoonotic disease reservoirs. Our models predict reservoir status in this group with over 90% accuracy, identifying species with high probabilities of harboring undiscovered zoonotic pathogens based on trait profiles that may serve as rules of thumb to distinguish reservoirs from nonreservoir species. Key predictors of zoonotic reservoirs include biogeographical properties, such as range size, as well as intrinsic host traits associated with lifetime reproductive output. Predicted hotspots of novel rodent reservoir diversity occur in the Middle East and Central Asia and the Midwestern United States.

The pace-of-life syndrome (POLS) hypothesis predicts that behavior and physiology covary with life history. Evidence for such covariation is contradictory, possibly because systematic sources of variation (e.g. sex) have been neglected. Sexes often experience different selection pressures leading to sex-specific allocation between reproduction and self-maintenance, facilitating divergence in life-history. Sex-specific differences in means and possibly variances may therefore play a key role in the POLS framework. We investigate whether sexes differ in means and variances along the fast-slow pace-of-life continuum for life history and physiological and behavioral traits. In addition, we test whether social and environmental characteristics such as breeding strategy, mating system, and study environment explain heterogeneity between the sexes. Using meta-analytic methods, we found that populations with a polygynous mating system or for studies conducted on wild populations, males had a faster pace-of-life for developmental life-history traits (e.g., growth rate), behavior, and physiology. In contrast, adult life-history traits (e.g., lifespan) were shifted towards faster pace-of-life in females, deviating from the other trait categories. Phenotypic variances were similar between the sexes across trait categories and were not affected by mating system or study environment. Breeding strategy did not influence sex differences in variances or means. We discuss our results in the light of sex-specific selection that might drive sex-specific differences in pace-of-life and ultimately POLS.

Many species are currently adapting to cities at different latitudes. Adaptation to urbanization may require eco‐evolutionary changes in response to temperature and invasive species that may differ between latitudes. Here, we studied single and combined effects of increased temperatures and an invasive alien predator on the phenotypic response of replicated urban and rural populations of the damselfly Ischnura elegans and contrasted these between central and high latitudes. Adult females were collected in rural and urban ponds at central and high latitudes. Their larvae were exposed to temperature treatments (current [20°C], mild warming [24°C], and heat wave [28°C; for high latitude only]) crossed with the presence or absence of chemical cues released by the spiny‐cheek crayfish (Faxonius limosus), only present at the central latitude. We measured treatment effects on larval development time, mass, and growth rate. Urbanization type affected all life history traits, yet these responses were often dependent on latitude, temperature, and sex. Mild warming decreased mass in rural and increased growth rate in urban populations. The effects of urbanization type on mass were latitude‐dependent, with central‐latitude populations having a greater phenotypic difference. Urbanization type effects were sex‐specific with urban males being lighter and having a lower growth rate than rural males. At the current temperature and mild warming, the predator cue reduced the growth rate, and this independently of urbanization type and latitude of origin. This pattern was reversed during a heat wave in high‐latitude damselflies. Our results highlight the context‐dependency of evolutionary and plastic responses to urbanization, and caution for generalizing how populations respond to cities based on populations at a single latitude.

Summary A phenotypic syndrome refers to complex patterns of integration among functionally related traits in an organism that defines how the organism interacts with its environment and sustains itself. Human‐induced biological invasions have become important sources of environmental modifications. However, the extent to which invasive species affect the phenotypic syndromes of individuals in a native is currently unknown. Such knowledge has important implications for understanding ecological interactions and the management of biological invasions. Here, field monitoring in a natural stream were combined with standardized estimates of behavioral, physiological and morphological traits to address the hypothesis that coexistence with a non‐native invader induces a novel environmental pressure that disrupts the adaptive integration among phenotypic traits of the native species. We compared the strength of integration among key phenotypic traits (i.e. aerobic scope, standard metabolic rate, body growth, activity, and body shape) and ecological niche traits (i.e. spring and summer diet, home range size, daily movements) of an allopatric group of native brown trout (Salmo trutta) with a group of brown trout living in sympatry with non‐native brook trout (Salvelinus fontinalis). We found that the integration of phenotypic traits was substantially reduced in the sympatric brown trout and that allopatric and sympatric brown trout differed in key phenotypic and ecological niche traits. Brown trout living in sympatry with non‐native brook trout consumed more terrestrial prey, had smaller home ranges, and a stouter body shape. Sympatric brown trout also had lower specific growth rate, suggesting a lower fitness. The results are generally in line with our hypothesis suggesting that the reduction in fitness observed in sympatric brown trout is caused by the breakdown of their adaptive phenotypic syndrome. This may be caused by differences in the plasticity of the response of phenotypic traits to the novel selection pressure induced by the non‐native species. Our results may help explaining deleterious effects of non‐native species reported in the absence of direct competition with the native species. A lay summary is available for this article. Lay Summary

In short-lived animals, individuals born earlier in the breeding season frequently reproduce within the season of birth. Consequently, it has been proposed that those born early benefit from a more proactive behavioral type to compete for reproductive opportunities whereas later-borns adopt a more reactive personality to conserve energy to survive through the non-breeding season and reproduce in the following year. However, being proactive could also benefit later-borns in acquiring decreasing resources in the late breeding season. We investigated personality differences depending on the date of birth in relation to resource variation in a free-living population of the bush Karoo rat (Otomys unisulcatus). This species constructs stick lodges, a critical resource protecting the rats from the harsh semi-desert environments, but the availability of vacant lodges decreases with increasing population density during the breeding season. We predicted an increased occurrence of proactive phenotypes during the later breeding season, contrasting with the commonly assumed decrease in proactive phenotypes in late season due to lack of reproductive opportunity. We behaviorally phenotyped n = 99 individuals through repeated behavioral tests and found consistent individual differences along a proactive-reactive gradient. Most importantly, later-borns showed greater activity, boldness and exploration tendencies, indicating a more proactive personality. In addition, among early-born females, individuals which reproduced showed no differences in personality compared to those which did not reproduce. Our results indicate that seasonal differences in personality types in the bush Karoo rat may be driven by resource constraints in the late season rather than by differences in reproduction opportunities.Significance statementIn short-lived animals, the birth date during the breeding season can lead to differences in life history and corresponding behavioral traits. We studied the link between birth date and personality in the bush Karoo rat, a seasonally-breeding and short-lived rodent which relies on a limited resource, stick lodges, essential to survive in a harsh semi-desert environment. Individuals born later in the season were more active, bolder and more explorative; these traits likely help them to successfully compete for stick lodges during the late breeding season when population density and thus competition is high. Early-born females, which can potentially start reproducing within their season of birth, showed no personality differences regardless of their reproductive status, suggesting that resource availability rather than reproduction opportunity may underly the emergence of seasonal personality differences in this species.

Mutual reinforcement between abiotic and biotic factors can drive small populations into a catastrophic downward spiral to extinction—a process known as the “extinction vortex.” However, empirical studies investigating extinction dynamics in relation to species' traits have been lacking. We assembled a database of 35 vertebrate populations monitored to extirpation over a period of at least ten years, represented by 32 different species, including 25 birds, five mammals, and two reptiles. We supplemented these population time series with species‐specific mean adult body size to investigate whether this key intrinsic trait affects the dynamics of populations declining toward extinction. We performed three analyses to quantify the effects of adult body size on three characteristics of population dynamics: time to extinction, population growth rate, and residual variability in population growth rate. Our results provide support for the existence of extinction vortex dynamics in extirpated populations. We show that populations typically decline nonlinearly to extinction, while both the rate of population decline and variability in population growth rate increase as extinction is approached. Our results also suggest that smaller‐bodied species are particularly prone to the extinction vortex, with larger increases in rates of population decline and population growth rate variability when compared to larger‐bodied species. Our results reaffirm and extend our understanding of extinction dynamics in real‐life extirpated populations. In particular, we suggest that smaller‐bodied species may be at greater risk of rapid collapse to extinction than larger‐bodied species, and thus, management of smaller‐bodied species should focus on maintaining higher population abundances as a priority. Our results reaffirm and extend our understanding of extinction dynamics in real‐life extirpated populations. In particular, we suggest that smaller‐bodied species may be at greater risk of rapid collapse to extinction than larger‐bodied species, and thus management of smaller‐bodied species should focus on maintaining higher population abundances as a priority.

Background Studying variation in life-history traits and correlated behaviours, such as boldness and foraging (i.e., pace-of-life syndrome), allows us to better understand how these traits evolve in a changing environment. In fish, it is particularly relevant studying the interplay of resource abundance and size-selection. These are two environmental stressors affecting fish in natural conditions, but also associated with human-induced environmental change. For instance, fishing, one of the most important threats for freshwater and marine populations, results in both higher mortality on large-sized fish and reduced population density. Results Medaka, Oryzias latipes, from lines selected for large or small size over ten generations, were exposed individually to high or low food availability from birth to adulthood. Maturation schedules, reproductive investment, growth, boldness and feeding were assessed to evaluate the effect of size-selection on the pace of life, and whether it differed between food contexts (high and low). Different food abundance and size-selection resulted in diverse life histories associated with different feeding and boldness behaviour, thus showing different pace-of-life-syndromes. High availability of food favoured faster growth, earlier maturation and increased shyness. Selection for small size led to slower growth in both males and females. But, the life-history trajectory to reach such growth was sex- and food-specific. Under low food conditions, females selected for small size showed earlier maturation, which led to slower adult growth and subsequent low willingness to feed, compared to females selected for large size. No line differences were found in females at high food conditions. In contrast, males exposed to selection for small size grew slower both as juvenile and adult, and were bolder under both feeding regimes. Therefore, the response to size-selection was more sensitive to food availability in females than in males. Conclusions We showed that size-selection (over ten generations) and resource abundance (over developmental time) led to changes in life history and behaviour. However, the effect of size-selection was sex- and context-specific, calling for precaution when drawing general conclusions on the population-level effects (or lack of them) of size-selective fishing. Conservation and management plans should consider this sex- and context-specificity.

Since the 1990s, new economic geography has received a lot of attention as mainstream economists such as Krugman and others began to focus on where economic activity occurs and why. Coincidentally, international trade, location theory, and urban economics all appear to be asking the same question: where is economic activity located and why? The challenge is to explain the economic concentration or agglomeration of a large number of activities in certain geographical space. This volume breaks down the various types of cities and evaluates the key factors used to look at cities, such as innovation, green growth, spatial concentration, and smart cities in order to understand how cities work. Why is it that certain cities attract talent? How do some cities become business hubs? Why is it that few cities become increasingly competitive while others remain stagnant?As development specialists are increasingly focusing on how to make cities competitive, this book can serve as a guide for providing key insights, backed by cases on how cities can possibly become more competitive and productive.