ENTERTAINING MALTHUS: BREAD, CIRCUSES, AND ECONOMIC GROWTH

The human colonization of Madagascar is associated with the extinction of numerous lemur species. However, the degree to which humans have negatively influenced the historical population dynamics of extant lemur species is not well understood. This study employs genetic and demographic analyses to estimate demographic parameters relating to the historical population dynamics of a wild lemur population, Verreaux's sifaka (Propithecus verreauxi). The genetic analyses are used to determine whether this population experienced a historically recent (i.e., within the last 2000 years) population bottleneck, as well as to estimate the historical population growth rate and the timing of any changes in population size in the past. In addition, a retrospective demographic analysis is used to determine sources of variation and covariation in the sifaka life cycle and how variation in life‐cycle transitions contributes to variation in population growth rate. The genetic analyses indicate that the sifaka population did not experience a recent population bottleneck; however, the historical population growth rate was negative, indicating that the ancestral population size was much larger than the current size. The timing of the ancestral population decline has a point estimate of 2300 years ago, but with large credible intervals: 3611–1736 years ago. This point estimate corresponds with the first evidence for human arrival to Madagascar. Climatic variation has also likely influenced past (and current) population dynamics due to stochastic annual rainfall patterns and climatic desiccation, the latter of which began in southwestern Madagascar around 4000 years ago. Variation in the survival of 2‐year‐old animals as well as large adult females makes the largest contribution to variation in population growth rate. In the absence of more explicit models pertaining to historical population dynamics, it is difficult to attribute the negative population growth rate of this species solely to a single factor (e.g., hunting, habitat destruction).

ABSTRACTIncreasingly imperative objectives in ecology are to understand and forecast population dynamic and evolutionary responses to seasonal environmental variation and change. Such population and evolutionary dynamics result from immediate and lagged responses of all key life‐history traits, and resulting demographic rates that affect population growth rate, to seasonal environmental conditions and population density. However, existing population dynamic and eco‐evolutionary theory and models have not yet fully encompassed within‐individual and among‐individual variation, covariation, structure and heterogeneity, and ongoing evolution, in a critical life‐history trait that allows individuals to respond to seasonal environmental conditions: seasonal migration. Meanwhile, empirical studies aided by new animal‐tracking technologies are increasingly demonstrating substantial within‐population variation in the occurrence and form of migration versus year‐round residence, generating diverse forms of ‘partial migration’ spanning diverse species, habitats and spatial scales. Such partially migratory systems form a continuum between the extreme scenarios of full migration and full year‐round residence, and are commonplace in nature.Here, we first review basic scenarios of partial migration and associated models designed to identify conditions that facilitate the maintenance of migratory polymorphism. We highlight that such models have been fundamental to the development of partial migration theory, but are spatially and demographically simplistic compared to the rich bodies of population dynamic theory and models that consider spatially structured populations with dispersal but no migration, or consider populations experiencing strong seasonality and full obligate migration. Second, to provide an overarching conceptual framework for spatio‐temporal population dynamics, we define a ‘partially migratory meta‐population’ system as a spatially structured set of locations that can be occupied by different sets of resident and migrant individuals in different seasons, and where locations that can support reproduction can also be linked by dispersal. We outline key forms of within‐individual and among‐individual variation and structure in migration that could arise within such systems and interact with variation in individual survival, reproduction and dispersal to create complex population dynamics and evolutionary responses across locations, seasons, years and generations. Third, we review approaches by which population dynamic and eco‐evolutionary models could be developed to test hypotheses regarding the dynamics and persistence of partially migratory meta‐populations given diverse forms of seasonal environmental variation and change, and to forecast system‐specific dynamics. To demonstrate one such approach, we use an evolutionary individual‐based model to illustrate that multiple forms of partial migration can readily co‐exist in a simple spatially structured landscape. Finally, we summarise recent empirical studies that demonstrate key components of demographic structure in partial migration, and demonstrate diverse associations with reproduction and survival. We thereby identify key theoretical and empirical knowledge gaps that remain, and consider multiple complementary approaches by which these gaps can be filled in order to elucidate population dynamic and eco‐evolutionary responses to spatio‐temporal seasonal environmental variation and change.

The evolution of present-day bourgeois political economy is a transmuted reflection of the development and intensification of the general crisis of capitalism. Three major stages are to be noted: a) the transition from so-called "classical" to Keynesian theory; b) the transition to neo-Keynesian theory of economic dynamics and economic growth; and c) the evolution of economic growth theory itself, its equipment with econometric concepts and new models of regulation and programming of the economy. Here, along with neo-Keynesian concepts and models, there has appeared a "neoclassical" theory of economic growth which has reestablished on a new foundation the notion of the self-regulation of the capitalist economy and of the possibility of stable equilibrium within it.

Tracking changes in seabird populations from remote Arctic regions using traditional monitoring techniques is financially and logistically challenging, leading to limited information on historical population trends. In this pilot study, we use a novel application of paleolimnological proxies to track environmental change using bird nests. Specifically, we examine long-term population dynamics of the Northern Common Eider (Somateria mollissima borealis), a philopatric sea duck. Eider nests from the Canadian sub-Arctic were sampled and radioisotopically dated, indicating that eiders have been nesting here since the 1800s. To assess the applicability of paleoecological proxies in nests to monitor environmental changes and long-term eider population dynamics, we examined changes in diatom species composition, shifts in the abundance of siliceous proxies (i.e., diatoms, chrysophyte cysts, phytoliths, protozoan plates), visible reflectance spectroscopy-inferred chlorophyll a (VRS-chla), stable nitrogen isotopes, and a selection of metal(loid)s. Warmer post-Little Ice Age conditions after the mid-19th century, together with higher eider occupation rates, promoted the proliferation of diatoms and other siliceous indicators. Declining eider populations during the industrial era, likely due to increased hunting pressures, was indicated by declines in δ15N values and relative abundances of diatom taxa typically associated with higher nutrients and/or moisture. Increasing concentrations of metals (i.e., Zn and Cd), δ15N values, and VRS-chla, which are positively associated with eider nesting activity, provided further support that eider numbers increased during the latter part of the 20th century. Our study shows that the accumulated vegetative and peat material from eider nests can provide a powerful tool to track historical bird population dynamics in ways that traditional, more recent, population monitoring methods cannot. Collectively, these methods can contribute insights to guide conservation decisions of this harvested species and other under-surveyed species.

Tracking changes in seabird populations from remote Arctic regions using traditional monitoring techniques is financially and logistically challenging, leading to limited information on historical population trends. In this pilot study, we use a novel application of paleolimnological proxies to track environmental change using bird nests. Specifically, we examine long-term population dynamics of the Northern Common Eider (Somateria mollissima borealis), a philopatric sea duck. Eider nests from the Canadian sub-Arctic were sampled and radioisotopically dated, indicating that eiders have been nesting here since the 1800s. To assess the applicability of paleoecological proxies in nests to monitor environmental changes and long-term eider population dynamics, we examined changes in diatom species composition, shifts in the abundance of siliceous proxies (i.e., diatoms, chrysophyte cysts, phytoliths, protozoan plates), visible reflectance spectroscopy-inferred chlorophyll a (VRS-chla), stable nitrogen isotopes, and a selection of metal(loid)s. Warmer post-Little Ice Age conditions after the mid-19th century, together with higher eider occupation rates, promoted the proliferation of diatoms and other siliceous indicators. Declining eider populations during the industrial era, likely due to increased hunting pressures, was indicated by declines in δ15N values and relative abundances of diatom taxa typically associated with higher nutrients and/or moisture. Increasing concentrations of metals (i.e., Zn and Cd), δ15N values, and VRS-chla, which are positively associated with eider nesting activity, provided further support that eider numbers increased during the latter part of the 20th century. Our study shows that the accumulated vegetative and peat material from eider nests can provide a powerful tool to track historical bird population dynamics in ways that traditional, more recent, population monitoring methods cannot. Collectively, these methods can contribute insights to guide conservation decisions of this harvested species and other under-surveyed species.

Population genetic variation and historical dynamics of the natural enemy insect Propylea japonica (Coleoptera: Coccinellidae) in China

Resequencing of white jute (Corchorus capsularis L.) provides insights into genome diversity, population historical dynamics, and improvement

Mitochondrial DNA sequence polymorphisms and patterns of genetic diversity represent the genealogy and relative impacts of historical, geographic, and demographic events on populations. In this study, historical patterns of population dynamics and differentiation in hawksbill (Eretmochelys imbricata) and green turtles (Chelonia mydas) in the Pacific were estimated from feeding populations in the Yaeyama Islands, Japan. Phylogenetic relationships of the haplotypes indicated that hawksbill and green turtles in the Pacific probably underwent very similar patterns and processes of population dynamics over the last million years, with population subdivision during the early Pleistocene and population expansion after the last glacial maximum. These significant contemporary historical events were suggested to have been caused by climatic and sea-level fluctuations. On the other hand, comparing our results to long-term population dynamics in the Atlantic, population subdivisions during the early Pleistocene were specific to Pacific hawksbill and green turtles. Therefore, regional differences in historical population dynamics are suggested. Despite limited sampling locations, these results are the first step in estimating the historical trends in Pacific sea turtles by using phylogenetics and population genetics.

Understanding the relative roles of climate and species interactions in regulating population dynamics, one of the oldest challenges in ecology, is now a prerequisite for predicting species responses to climate change. A lack of case studies limits our ability to generalize about the factors that have regulated populations in the past and will be important in the future. Here, we take a first step toward identifying the drivers of plant population dynamics by studying the influence of climate and species interactions on the recruitment and survival of ten forb species from a Kansas (USA) prairie. Combining a long-term demographic data set with a Bayesian hierarchical-modeling approach, we fit models in which annual survival and recruitment rates are driven by precipitation, temperature, and species composition. Although the effects of these covariates differed among species, three general patterns emerged. First, climate had a greater influence than species composition on historical population dynamics. Second, forecasted increases in mean temperatures are likely to impact the population growth of these species more than future changes in precipitation or composition. Third, the significant effects of both climate and species composition on recruitment suggest that range expansions will be particularly difficult to forecast. Based on these patterns, we recommend field experiments to evaluate the ability of plant species to recruit at expanding range margins under warmer temperatures.

Modelling the past and future of whales and whaling

evolutionary computing (EC), population size is one of the critical parameters that a researcher has to deal with. Hence, it was no surprise that the pioneers of EC, such as De Jong (1975) and Holland (1975), had already studied the population sizing from the very beginning of EC. What is perhaps surprising is that more than three decades later, we still largely depend on the experience or ad-hoc trial-and-error approach to set the population size. For example, in a recent monograph, Eiben and Smith (2003) indicated: In almost all EC applications, the population size is constant and does not change during the evolutionary search . Despite enormous research on this issue in recent years, we still lack a well accepted theory for population sizing. this paper, I propose to develop a population dynamics theory forEC with the inspiration from the population dynamics theory of biological populations in nature. Essentially, the EC population is considered as a dynamic system over time (generations ) and space (search space or fitness landscape ), similar to the spatial and temporal dynamics of biological populations in nature. With this conceptual mapping, I propose to 'transplant' the biological population dynamics theory to EC via three steps: (i ) experimentally test the feasibility--whether or not emulating natural population dynamics improves the EC performance; (ii ) comparatively study the underlying mechanisms--why there are improvements, primarily via statistical modeling analysis; (iii ) conduct theoretical analysis with theoretical models such as percolation theory and extended evolutionary game theory that are generally applicable to both EC and natural populations. This article is a summary of a series of studies we have performed to achieve the general goal [27][30]---[32]. the following, I start with an extremely brief introduction on the theory and models of natural population dynamics (Sections 1 & 2). Sections 4 to 6, I briefly discuss three categories of population dynamics models: deterministic modeling with Logistic chaos map as an example, stochastic modeling with spatial distribution patterns as an example, as well as survival analysis and extended evolutionary game theory (EEGT) modeling. Sample experiment results with Genetic algorithms (GA) are presented to demonstrate the applications of these models. The proposed EC population dynamics approach also makes survival selection largely unnecessary or much simplified since the individuals are naturally selected (controlled) by the mathematical models for EC population dynamics.

Describing patterns of connectivity among populations of species with widespread distributions is particularly important in understanding the ecology and evolution of marine species. In this study, we examined patterns of population differentiation, migration, and historical population dynamics using microsatellite and mitochondrial loci to test whether populations of the epinephelid fish, Gag, Mycteroperca microlepis, an important fishery species, are genetically connected across the Gulf of Mexico and if so, whether that connectivity is attributable to either contemporary or historical processes. Populations of Gag on the Campeche Bank and the West Florida Shelf show significant, but low magnitude, differentiation. Time since divergence/expansion estimates associated with historical population dynamics indicate that any population or spatial expansions indicated by population genetics would have likely occurred in the late Pleistocene. Using coalescent-based approaches, we find that the best model for explaining observed spatial patterns of contemporary genetic variation is one of asymmetric gene flow, with movement from Campeche Bank to the West Florida Shelf. Both estimated migration rates and ecological data support the hypothesis that Gag populations throughout the Gulf of Mexico are connected via present day larval dispersal. Demonstrating this greatly expanded scale of connectivity for Gag highlights the influence of “ghost” populations (sensu Beerli) on genetic patterns and presents a critical consideration for both fisheries management and conservation of this and other species with similar genetic patterns.

Urbanization and its diverse forms and patterns have become central to global research as the world shifts its focus toward building sustainable, resilient, and livable cities. As urban areas grow in size and population, unplanned development frequently leads to inefficient land use, unsustainable spatial transformations, environmental degradation, and inadequate urban services. Addressing these challenges is critical to global sustainability, particularly when viewed through the lens of the urban critical zone—a dynamic space where human activities and natural systems interact, influencing resource flows and urban resilience.Delhi, the National Capital Territory of India, exemplifies these challenges and opportunities, making it an ideal case study for urbanization. As one of the world's fastest-growing metropolitan regions, it has undergone rapid demographic and spatial transformations, characterized by unique patterns of urban sprawl and rural-urban transitions. Understanding Delhi’s urban growth trajectory provides valuable insights into managing similar dynamics in other rapidly urbanizing regions.This study examines the urban growth patterns of Delhi over the period 1990 to 2024 using satellite imagery and GIS to analyze spatial and temporal dynamics. The study adopts a multi-method approach to capture the complexities of urban growth. The three-growth mode hypothesis (infill, edge-expansion, and leapfrogging) is applied to identify and quantify distinct spatial dynamics of urbanization. Urban Field Intensity (UFI) analysis highlights areas experiencing maximum growth, while the Normalized Difference Expansion Index (NDEI) is used to assess sprawling or shrinking tendencies of the city over time. Future urban growth for the years 2030 and 2050 is projected using spatial simulation techniques, integrating historical growth trends, population dynamics, and land-use data to predict potential urban transformations. Additionally, field visits to critical zones—including rapidly transforming rural areas, infill-dominated regions, and outlying development zones—were conducted to validate spatial analyses and explore human-environment interactions. These combined approaches provide a comprehensive framework to evaluate urban growth and its implications for sustainability.The results reveal that Delhi's urban growth is predominantly characterized by edge-expansion, with intermittent infill and leapfrogging patterns. Declining NDEI values across the study period indicate increased sprawl, posing sustainability challenges. UFI analysis highlights significant land transformation in rural areas, with specific zones experiencing up to a 60% increase in urban activity. The adjacent counter-magnet cities of Ghaziabad, Noida, Faridabad, and Gurugram significantly influence the region's urban dynamics. Field observations corroborate these findings, revealing acute infrastructure deficits in transition zones, particularly in water supply, transportation networks, and waste management. These insights underscore the urgency of targeted interventions to address sustainability challenges in Delhi’s sprawling urban regions.This study underscores the need for region-specific strategies that harness sprawling tendencies to achieve sustainable urban growth. By advocating for the "make room" paradigm, it emphasizes urban planning approaches that integrate the interactions between human activities and critical biophysical processes to enhance resilience in rapidly growing urban areas.Keywords: Urbanization, Urban sprawl, Sustainability, Urban critical zone, Spatial analysis

Summary For the overwhelming majority of species, we lack long‐term information on the dynamics of populations. As a consequence, we face considerable uncertainty about how to discriminate among competing hypotheses of population decline and design conservation plans. The marbled murrelet Brachyramphus marmoratus is a small seabird that nests in coastal old‐growth forest but feeds year‐round in near‐shore waters of the north‐eastern Pacific. Although a decline in nesting habitat is the primary reason why marbled murrelets are listed as threatened in Canada, nest predation and food availability may also influence population abundance. To examine the hypothesis that murrelet populations are influenced by variation in diet quality, we analysed stable‐carbon and ‐nitrogen isotopes in feathers of museum specimens collected in the Georgia Basin, British Columbia. Between 1889 and 1996, we found a decline in stable isotopic signatures that was approximately equal to a 62% drop in trophic feeding level. We also found that the estimated proportion of fish in murrelet diet was related closely to murrelet abundance over the past 40 years, as estimated from volunteer surveys. Using these isotopic data, we modelled population size as a function of variation in reproductive rate due to changes in diet quality and found that our model matched closely the 40‐year field estimates. We then applied our 107‐year isotopic record to the model to back‐cast estimates of population growth rate to 1889. Our results suggest that, up to the 1950s, murrelet populations in the Georgia Basin were capable of growing and were probably limited by factors other than diet quality. After this period, however, our results imply that murrelets were often, but not solely, limited by diet quality. Synthesis and applications. Protecting nesting habitat may not be sufficient to rebuild populations of this highly secretive and threatened seabird and recovery might also require the restoration of marine habitat quality, as well as a better understanding of how ocean climate affects prey abundance and reproductive rate. Combined with contemporary demographic data, stable isotope analysis of historic samples provides a unique opportunity to reconstruct population histories for species where we lack long‐term information.

The spatial population dynamics of the wolfspider Pardosa monticola, inhabiting patchily distributed grasslands in the Flemish coastal dunes of Belgium and Northern France were investigated with incidence function models using field survey data from 1998 and 2000. Vegetation height and patch size were related to habitat quality. Mark-recapture experiments revealed maximum cursorial dispersal distances of 280 m for moss dunes and 185 m for higher dune grassland. Higher shrub vegetation appeared to be dispersal barriers. These habitat-dependant cursorial distances and the theoretically estimated ballooning distance were included with patch distances into a connectivity index for both dispersal modes. Forward multiple regression indicated that patch occurrence was influenced by habitat quality and ballooning connectivity. Habitat quality and cursorial connectivity explained patterns in short-term colonisation. Extinction appeared to be stochastic and not related to habitat quality and connectivity. Genetic differentiation and variability was low. The discrepancy between the estimated low dispersal capacity and the indirect estimate of gene flow ( F(ST)) indicates that historical population dynamics and/or historical ballooning dispersal influence the genetic structure in this species.