Population Growth Rate Research Articles

Deciphering Trends in Cancer Mortality: A Comprehensive Analysis of Brazilian Data From 1979 to 2021 With Emphasis on Breast and Prostate Cancers.

This study examined cancer mortality trends in Brazil from 1979 to 2021, emphasizing breast and prostate cancers. Utilizing data from the Brazilian Mortality Information System and the Brazilian Institute of Geography and Statistics, it analyzed cancer deaths nationally and regionally, highlighting gender-specific and regional disparities. The research finds that cancer death rates have been growing at an average of 12% per year, contrasting with the population growth rate of 2.2%. This trend is more pronounced in the southern and southeastern regions of Brazil. A comparison of cancer mortality rates between Brazil, the USA, and China reveals that while the Brazilian and Chinese rates exhibit slower growth, the US rate shows a continuous decline since the 1990s. The study adopts a novel approach by focusing on growth rates and employing polynomial interpolation, revealing a deceleration in cancer death growth over the last 15 years across all malignant neoplasms. The study also contextualizes these findings within Brazil's cancer control policies, tracing the evolution of preventive measures and treatment advancements. It highlights the significant role of the National Cancer Institute and the Unified Health System in implementing effective strategies. The decreasing trend in cancer mortality rates in Brazil, despite population growth, illustrates the effectiveness of comprehensive cancer control and prevention measures, underlining their importance in public health policy.

Study on Driving Factors and Spatiotemporal Differentiation of Eco-Environmental Quality in Jianghuai River Basin of China

For an in-depth analysis of the ecosystems of the Jianghuai Valley, this study utilized municipal data from 2017 to 2021. In addition, this study established an index scale evaluation system for the quality of the ecological environment in the Jianghuai Valley. This system encompasses five critical dimensions: drivers, pressures, states, impacts, and responses, in accordance with the DPSIR model. The entropy-weighted TOPSIS method combined with the gray correlation method was used to assess the ecological status of each region of the Jianghuai Valley at different time periods and the driving factors affecting the ecological quality of the Jianghuai Valley. Our study yields several key conclusions. First, it was observed that the ecological environment within the Jianghuai Valley showed a continuous upward bias in inter-annual variability. Second, there exists variation in ecological environment quality among the eleven urban areas within the Jianghuai Valley, highlighting regional disparities. Third, among the eleven urban areas in the Jianghuai Valley, Anqing has the best ecological quality, and Huainan has the worst ecological performance. Fourth, the ecological environment quality within the Jianghuai Valley demonstrates an aggregated pattern. From west to east, this pattern is delineated by distinct areas: one marked by excellent ecological environment quality, another exhibiting average ecological environment quality, followed by a zone characterized by good ecological environment quality, and finally, an area with poor ecological environment. Fifth, our analysis reveals that Q9 (indicating the percentage of excellent air days) and Q13 (denoting the annual average temperature) have a pronounced correlation with the Jianghuai Valley’s ecological quality. Conversely, Q3, which pertains to the rate of natural population growth, had the lowest relevance to the ecological quality of the Jianghuai Valley.

Reframing policy responses to population aging in Iran

Iran is aging rapidly and is expected to see negative population growth rates later this century. This change is generating significant concern for policymakers, whose response is to seek ‘demographic solutions’ to these issues: raise the fertility rate, decrease the divorce rate, and promote marriage among young people. Part of these policies has entailed curtailing access to free family planning services. This ‘call and response’ approach is unlikely to succeed in its stated aim, as it over-simplifies the real challenges of population aging as well as the multiple dimensions of population change. Such policies derive from simple representations of demographic change, most notably using the old-age dependency ratio. Using a microsimulation model, this paper suggests that increasing Iran’s currently low female labor force participation and translating educational gains into rising productivity is a more effective means of responding to the challenges of population aging, even under low fertility conditions. The advancement on previous such microsimulation exercises lies in the fact that this study explicitly considers the comparison between raising fertility and increasing female economic empowerment to offset population aging in a setting characterized by an overt pronatalist policy system. In tandem with reforming stressed institutional systems (such as the pension system), releasing the full potential of Iran’s existing (and future) human capital—especially of its women—is a far more effective policy direction than fertility-promoting policies.

Modeling Population Growth under Climate Stressors Using Age-structured Matrix Models.

Climate resilience, a focus of many recent studies, has been examined from ecological, physiological, and evolutionary perspectives. However, sampling biases towards adults, males, and certain species have made establishing the link between environmental change and population-level change problematic. Here we used data from four laboratory studies, in which we administered pre- and post-natal stressors, such as suboptimal incubation temperature, heat stress, and food restriction, to zebra finches and quantified hatching success, post-hatch survival, and reproductive success, to parameterize age-structured population dynamics models with the goal of estimating the effect of the stressors on relative population growth rates. Using the same model structure, we tested the hypothesis that early life stages influence population growth rate more than later life stages. Our models suggested that stressful events during embryonic development, such as suboptimal incubation temperatures and reduced gas exchange for the embryos, have a greater total impact on population growth than post-hatch stressors, such as heat stress and food restriction. However, among life history traits, differences in hatching success and sex ratio of offspring in response to stressors changed population growth rates more than differences in any other demographic rate estimates. These results suggest that when predicting population resilience against climate change, it is critical to account for effects of climate change on all life stages, including early stages of life, and to incorporate individuals' physiology and stress tolerance that likely influence future stress responses, reproduction, and survival.

Resilient Response to Combined Heat and Drought Stress Conditions of a Tomato Germplasm Collection, Including Natural and Ethyl Methanesulfonate-Induced Variants

Agricultural systems are currently facing significant issues, primarily due to population growth rates in the context of global climate change. Rising temperatures cause plant heat stress and impact crop yield, which in turn compromises global food production and safety. Climate change is also having a significant impact on water availability around the world, and droughts are becoming more frequent and severe in many regions. The combined effect of both heat and drought stresses increases plant damage, resulting in reduced plant development and productivity loss. Therefore, developing heat–drought-tolerant crop varieties is crucial for enhancing yield under these challenging conditions. Tomato (Solanum lycopersicum L.), a major vegetable crop highly appreciated for its nutritional qualities, is particularly sensitive to extreme temperatures, which have a significant negative impact on tomato fruit setting and cause male gametophyte abortion. In this work, a classical genetic approach was employed to identify tomato genotypes showing a resilient response to combined heat and drought stress conditions. A phenotype screening of a natural germplasm collection and an ethyl methanesulfonate (EMS) mutagenized population resulted in the identification of a significant number of tomato lines tolerant to combined heat and drought conditions, specifically 161 EMS lines and 24 natural accessions as tolerant. In addition, TILLING and Eco-TILLING analyses were used as proof-of-concept to isolate new genetic variants of genes previously reported as key regulators of abiotic stress responses in different species. The identification of these variants holds the potential to provide suitable plant material for breeding programs focused on enhancing tomato resilience to adverse climate conditions.

Tracking the scaling of urban open spaces in China from 1990 to 2020

Urban open spaces (UOS) are crucial for urban life, offering benefits across individual and societal levels. However, the understanding of the systematic dynamic of UOS scaling with city size and its potential non-linear performance remains a limited clarity area. This study bridges this gap by integrating urban scaling laws with remote sensing data from 1990 to 2020, creating a framework to analyze UOS trends in China. Our findings reveal that UOS growth is sub-linear scaling with city size, exhibiting economies of scale with scaling exponents between 0.55 and 0.65 and suggesting potential shortages. The distribution structure of UOS across cities is becoming increasingly balanced, as indicated by the rising Zipf’s slope from 0.66 to 0.88. Southeastern coastal cities outperform, highlighting spatial variations and path dependency in UOS development. Additionally, using metrics of Scale-adjusted metropolitan indicator (SAMI) and the ratio of open space consumption to population growth rates (OCRPGR), we observe a trend towards more coordinated development between UOS and population, with a declining proportion of uncoordinated cities. Our long-term, large sample coverage study of UOS in China may offer positive significance for urban ecological planning and management in similar rapidly urbanizing countries, contributing to critical insights for quantifying and monitoring urban sustainable development.

National Population Growth Rate, Its Components, and Subnational Contributions: A Research Note.

A population's current growth rate is determined jointly by changes in fertility, mortality, and migration. This overall growth rate is also the average of age-specific growth rates, which can be decomposed into the result of historical changes in fertility, mortality, and migration. However, doing so requires more than 100 years of historical data, meaning that such analyses are possible only in a select few populations. In this research note, we propose an adapted version of the variable-r model to measure contributions to the population growth rate for countries with shorter demographic series. In addition, we extend this model to explore the contribution of subnational changes to the national population growth rate. Our results demonstrate that the age-specific growth rates obtained from short historical series, say 25 years, closely match those of the longer series. These abbreviated age-specific growth rates closely resemble the growth rate at birth of their respective cohorts, which is the major determinant of population growth, except at older ages where mortality becomes the main explanatory element. Exploring subnational populations, we find considerable heterogeneity in the age profile of the components of growth and find that the most populous regions tend to have an outsized impact on national-level growth.

Convergence of aquatic products consumption: A disaggregated analysis in European countries

Several benefits of consuming fishery and aquaculture products have been documented by the extant literature. However, the literature has been largely silent on few dimensions of aquaculture products, including the convergence of aquatic products consumption. An importance of investigating the convergence of aquatic products is that it provides hindsight on which countries should be the focus of exporters of the products. Convergence analysis of aquatic products consumption provides information that is relevant to the need to boost local production of aquatic products, and to conserve foreign exchange earnings. The aim of this study is to investigate the convergence of total aquatic products consumption per capita in 27 European Union countries plus United Kingdom, during 1993–2019. We have further considered the convergence of the components of total aquatic products consumption, which include aquatic animals, cephalopods, crustaceans, demersal fish, freshwater fish, marine fish, molluscs, and pelagic fish. Additionally, we have examined conditional convergence by evaluating the determinants of convergence of total aquatic products consumption. Using recently introduced unit root tests that provide for both smooth and sharp breaks, the results provide support for stochastic convergence of total aquatic products consumption per capita. Using a new conditional convergence approach, the analysis demonstrates that population growth rate, real gross domestic product, and prices of aquatic products are factors that enable the convergence of total aquatic products. The results are not materially different across the components of total aquatic products consumption. The implications of the results are discussed in the paper.

Efficiency and greenness evaluation of urban land use change in the Yangtze River Economic Belt, China

AbstractImproving urban land use efficiency and greenness is essential for achieving sustainable urban development and improving the well‐being of urban settlements. Using satellite‐based land use data, socioeconomic data, and sustainable development goal (SDG) indicators, we quantified the changes in the urban land use efficiency and greenness under rapid urban expansion in provincial cities in the Yangtze River Economic Belt (YREB) from 1990 to 2020. Over this period, urban area increased significantly, by 254.57%, at a rate of 191.41 km2 per year in the YREB, as national macro‐policies shifted the center of urban expansion westward. Nevertheless, the urban land use efficiency and greenness have both increased. The ratio of land consumption rate to population growth rate increased from 0.55 in 1990–2000 to 0.83 in 2010–2020 in the YREB, accompanied by an increase in the investment output ratio of fixed assets. In addition, the population‐weighted greenspace exposure increased by 5.31%, due to an 8.16% increase in the urban greenspace coverage, which improved the urban living environment amidst substantial urban population growth. We emphasize the importance of fostering coordinated development between central and western cities in the YREB. The results provide an important reference for the rational allocation of land resources, improving land use efficiency, and building resilient cities within global urbanization hotspots under the SDG framework.

Analisis Tujuan Pembangunan Berkelanjutan (SDGs): Mengurangi Kesenjangan di Provinsi Jawa Timur

One of the goals of sustainable development is to reduce income inequality. This research aims to find out what variables influence the income gap. The research objects were 38 regencies/cities in East Java. The data used in the study is secondary data for 2019 - 2022 sourced from the Central Statistics Agency (BPS) of East Java Province, which was taken using documentation techniques. The analytical tool used is panel data regression. The research results show that the average length of schooling positively and significantly affects income inequality. The Population Growth Rate has a negative and significant effect on Income Inequality. Economic Growth has a positive and significant impact on Income Inequality.

Analisis Produktivitas Alat Berat dalam Pengelolaan Sampah di Kecamatan Sukarami Kota Palembang

In Indonesia, solid waste has become a problem for municipalities, which could result in hygienic and aesthetically unpleasant issues. The high rate of population growth will have an impact on waste generation since it will change the needs and lifestyles of city dwellers. The collection, transportation, and final disposal of urban solid waste (TPA) require suitable facilities and infrastructure, particularly hefty equipment. Heavy equipment, specifically waste trucks, and heavy digging equipment, plays a significant part in supporting waste management activities. In particular, the Palembang City region is covered in this study's discussion of the productivity of heavy machinery used in waste management, which might begin with the collecting system, transportation system, and heavy equipment employed at the landfill. The study was conducted in Palembang City's Sukarami District, and data was collected by surveying and observing the current condition of the heavy equipment that was already in place, namely in terms of cycle time variables and the volume of waste that was served. The findings of the study indicate that direct communal and direct individual patterns characterize the region's waste-collecting practices. Dump trucks, which are used to transport waste, had a productivity range of 609.98 to 1266.13 kilograms per hour, while bulldozers and excavators had a range of 759.42 to 1166.17 kilograms per hour. This heavy equipment repair recommendation is targeted at bulldozers and excavators since a field investigation reveals that there are now only 2 pieces of bulldozer heavy equipment and 1 unit of excavator heavy equipment available.

How to quantify developmental synchrony in malaria parasites

Malaria infections represent an iconic example of developmental synchrony, where periodic fevers can result when the population of parasites develops synchronously within host red blood cells. The level of synchrony appears to vary across individual hosts and across parasite species and strains, variation that—once quantified—can illuminate the ecological and evolutionary drivers of synchrony. Yet current approaches for quantifying synchrony in parasites are either biased by population dynamics or unsuitable when population growth rates vary through time, features ubiquitous to parasite populations in vitro and in vivo. Here we develop an approach to estimate synchrony that accounts for population dynamics, including changing population growth rates, and validate it with simulated time series data encompassing a range of synchrony levels in two different host-parasite systems: malaria infections of mice and human malaria parasites in vitro. This new method accurately quantifies developmental synchrony from per capita growth rates using obtainable abundance data even with realistic sampling noise, without the need to sort parasites into developmental stages. Our approach enables variability in developmental schedules to be disentangled from even extreme variation in population dynamics, providing a comparative metric of developmental synchrony.

Temporal and Spatial Influences on Fawn Summer Survival in Pronghorn Populations: Management Implications from Noninvasive Monitoring.

Monitoring vital rates allows managers to estimate trends in growth rates of ungulate populations. However, connecting the influence of nutrition on ungulate demography is challenging. Noninvasive sampling offers a low-cost, low-effort alternative for measuring nutritional indices, allowing for an increased understanding of the mechanistic relationships between environmental factors, nutrition, and specific population vital rates. We examined the temporal influence of intrinsic and extrinsic factors on pronghorn (Antilocapra americana) fawn recruitment. We collected fresh fecal samples from adult female pronghorn in five subpopulations spanning three sampling periods associated with critical maternal life-history stages (late gestation, early lactation, breeding season) for 2 years to investigate both intra- and interannual influences. Intrinsic factors were fecal glucocorticoid metabolites (FGMs), nutritional indices (fecal nitrogen (FN) and 2,6-diaminopimelic acid (DAPA)), and dietary composition (protein intake of forbs, graminoids, legumes, other, shrubs), while the extrinsic factor was vegetative greenness (normalized difference vegetation index (NDVI)). We found variations in DAPA, protein intake of forbs, variation in forb protein intake, and protein intake of legumes during late gestation positively influenced fawn recruitment. Fecal nitrogen during early lactation showed the strongest positive influence on the recruitment of any measured parameter. Finally, breeding season NDVI and the variation in DAPA values positively influenced the subsequent year's fawn recruitment. Our longitudinal study enabled us to investigate which parameter was most important to specific periods of fawn development and recruitment. We combined the results across five subpopulations, but interpretation and subsequent management decisions should be made at the subpopulation level such that pronghorn subpopulations with low recruitment can be positively influenced by increasing nitrogen on the landscape available to adult females during the early lactation period. As the use of noninvasive monitoring methods continues to expand, we believe our methodologies and results can be broadly applied to other ungulate monitoring programs.

Sociodemographic and Contextual Determinants of Men’s Fertility Desires in Northern Nigeria: An Analysis of the 2018 Demographic and Health Survey

Nigeria has a high fertility rate, averaging 5.1 children per woman. The desire for large families, especially by men from the northern region, is a crucial driver of the country’s high total fertility rate. There is, however, a shortage of evidence on the sociodemographic determinants of men’s fertility desires despite being essential stakeholders in fertility decisions in the family. This study, therefore, estimates men’s desired family sizes and the sociodemographic and contextual factors influencing their desires in the northern region of Nigeria. Data from the men’s recoded 2018 Nigeria Demographic and Health Survey dataset were used with a sample of 7,822 men. The chi-square test and ordinal logistic regression analysis were used to test the association and estimate the relationship between the outcome and predictor variables. The findings revealed that 71% of men desired to have at least six children, which was high irrespective of sociodemographic characteristics. However, the desire for six or more children was lower (65%) among the youngest cohort than among the oldest (80%). Being a Muslim (AOR = 4.50, 95% CI [3.86, 5.24], p < .05), having two or more wives (AOR = 2.41, 95% CI [1.68, 3.45], p < .05), having 3–5 (AOR = 2.28, 95% CI [1.89, 2.76], p < .05) and six or more (AOR = 6.03, 95% CI [4.48, 8.13], p < .05) living children, and living in the northeast (AOR = 2.03, 95% CI [1.75, 2.37], p < .05) and northwest (AOR = 1.44, 95% CI [1.20, 1.72], p < .05) zones were the most significant predictors of high fertility desire by men. Policymakers should target these categories of men in fertility and family planning programs to promote lowering and slowing the rate of fertility and population growth.

Embodied Energy Coefficient Quantification and Implementation for an Energy-Conservative House in Thailand

Embodied Energy Coefficient Quantification and Implementation for an Energy-Conservative House in Thailand

Effects of urea topdressing time on yield, nitrogen utilization, and quality of mechanical direct-seeding hybrid indica rice under slow-mixed fertilizer base application.

The use of controlled-release nitrogen (N) fertilizers has been shown to improve yield and N-use efficiency (NUE) in mechanical transplanted rice. However, the fertilizer requirements for mechanical direct-seeding rice differ from those for mechanical transplanted rice. The effects of controlled-release fertilizers on yield, NUE, and quality in mechanical direct-seeding rice are still unknown. Hybrid indica rice varieties Yixiangyou 2115 and Fyou 498 were used as test materials, and slow-mixed N fertilizer (120kg hm-2) as a base (N1), N1+urea-N (30kg hm-2) once as a base (N2), N1+urea-N (30kg hm-2) topdressing at the tillering stage (N3), N1+urea-N (30kg hm-2) topdressing at the booting stage (N4) four N fertilizer management to study their impact on the yield, NUE and quality of mechanical direct-seeding rice. Compared with Yixiangyou 2115, Fyou 498 significantly increased photosynthetic potential, population growth rate, root vigor, and N transport rate by 3.34-23.88%. This increase further resulted in a significant improvement in the yield and NUE of urea-N topdressing by 1.73-5.95 kg kg-1. However, Fyou 498 showed a significant decrease in the head rice rate and taste value by 3.34-7.67%. All varieties were treated with N4 that significantly increase photosynthetic potential and population growth rate by 15.41-62.72%, reduce the decay rate of root vigor by 5.01-21.39%, promote the N transport amount in stem-sheaths (leaves) by 13.54-59.96%, and then significantly increase the yields by 4.45-20.98% and NUE of urea-N topdressing by 5.20-45.56 kg kg-1. Moreover, the rice processing and taste values were optimized using this model. Correlation analysis revealed to achieve synergistic enhancement of high-yield, high-quality, and high-NUE in rice, it is crucial to focus on increasing photosynthetic potential, population growth rate, and promoting leaf N transport. Specifically, increasing the contribution rate of N transport in stem-sheaths is the most important. These findings offer an effective N management strategy for 4R nutrient stewardship (right source, right method, right rate and right timing) of mechanical direct-seeding hybrid indica rice.

Effects of Urban Growth and Urbanization on the Social Environment: Case Study Old and Modern Cities of Yemen

Aim: This research was designed to study the effects of urban growth and urbanization on the social environment (Study of the state of growth and social changes in the old and modern cities of Yemen an example). Background: Yemenis have a rich history of urban centers, which have played a crucial role in trade, crafts, industries, and science. These cities have become distinct areas of cultural development, economic polarization, and cultural radiation. They are considered crucibles for social culturalintegration, nurseries for political growth, and areas for the development of national consciousness. The history of Yemen's cities and urban centers demonstrates the close link between trade, delivery routes, political governance centers, and city growth and development. Some Yemeni historical cities have played a vital role before Islam as political capitals, educators, and seaports. Cities have emerged as a result of the desire to coexist and achieve stability, reflecting spiritual, material, social, and political conditions. The growth of cities and architecture is a reflection of these changes. Methodology: The physical changes in the Republic of Yemen and the identification of the city of Aden were studied by reviewing the studies that monitored these changes and their social, economic and population effects. The study relied on secondary data in the first place. Conclusion: Yemen's population growth rate in 2004 was low at 3.01%, but it remains high due to economic and social developments and changes demographic factors such as fertility, mortality, and migration the growth rate was decreased at 2.20%. The 2004 General Population and Housing Census revealed that the resident population is spread across various governorates, with Ta'izz, Hodeidah, and Ibb having the highest proportions. The General Census of Population and Establishments revealed changes in the relative weight of the provincial population between the 1994 and 2004 censuses, with some governorates experiencing an increase in population relative to the population, while others experienced a decrease. The annual growth rate of the resident population was 3.0%, and the proportion of the young age group increased from 46.2% in 1994 to 51.5% in 2004. The gender ratio in Yemen is 104, with some governorates having a higher proportion of species due to urbanization (male than more than female), employment opportunities, or male labor migration. The Central Statistical Agency predicts that population growth will remain high over the next 20 years, with a natural increase rate of 3.01%. The proportion of married people in the population is higher for both sexes, possibly due to increased living costs and lack of adequate housing.

Dynamics of Per-Urban Land Alteration in and Around Siliguri City, India: A Geo-Spatial Study

Urban studies in more detailed form have emphasized zonal development and spatio-temporal transformation of cities. With the progress of time, the city expands outward, which gives birth to new urban areas. While areas within the administrative boundary of a city often goes through the process of planning, those, outside the administrative jurisdiction of the city often lack proper management and organization of land. This often results in haphazard urban growth and proliferation of semi-formal settlements within the peri-urban setting of developing nations. The present study was conducted for exploring the dynamics of peripheral urban land alterations in and around Siliguri city. For in-depth research, three buffer zones were delineated and supervised classification-based satellite images were incorporated to visualize the usage and coverage of land (LULC) based transformations of over the years. In addition, NDVI and LST were used to trace the changes in vegetation quality and surface temperature at the buffer zone level. The findings show a deterioration in vegetation health and an increase in surface temperature of the land in newly developed built-up and desolate regions. All three buffer zones showed a negative association the temperature of the land surface and the health of the vegetation. Furthermore, spatial extent of built-up land determined by remote sensing data was compared to population growth rates to calculate the Land Conversion Rate-Population Growth Rate (LCRPGR). The study emphasizes that peri-urbanization has accelerated the spread of built-up areas across the three zones, reflecting population constraints on land and yielding an overall LCRPGR value of 3.22. Importantly, the study demonstrated how the change-induced evidence of peri-urban dynamics has led to land transformation in the study area. Importantly, the study highlights how evidence of peri-urban dynamics reveals land changes in the studied area. It demonstrates how the rapid rise of people and development, along with limited available land space, drives the rapid alteration of peri-urban areas inside urban cityscape.

Crucial impact of component Allee effect in predator-prey system

Allee effect in models in interacting species of predator prey system has great significance in ecological context. Allee effect plays crucial role in population dynamics in ecology, where it is the challenging fact that per capita population growth rate is positively dependent on the population density of a species. In this paper, we inspect the famous Hastings and Powell (HP) (Hastings and Powell 1991 Ecology 72 896–903) model incorporating component Allee effect on top predator’s reproduction. We analyse the updated model with the help of both analytical and numerical phenomena. Considering cost of Allee effect, half-saturation constant of prey as the key parameters, the Hopf bifurcations are also analysed. The directions of Hopf bifurcations at the critical values of Allee parameter and half-saturation constant of prey are studied theoretically by using normal form theory introduced by Hassard et al (1981 Theory and Applications of Hopf Bifurcation vol 41 (CUP Archive)). The formulated model indicates that the system demonstrates chaotic, periodic and stable dynamics in the variation of key parameters. The chaos can be controlled for proper application of the large values of parameter used as the cost of Allee effect and also for small values of the parameter used as the half saturation constant of prey population. The results of this study are applicable in the field of marine and wild ecosystem dynamics.

Identifying impactful sea turtle conservation strategies: a mismatch between most influential and most readily manageable life-stages

Sea turtles worldwide face a range of threats including sea level rise and warming associated with climate change, predation by invasive species, plastic and light pollution, coastal development, and human interference. Conservation managers have a long history of aiding sea turtle populations, from protecting nests to head-starting hatchlings. Due to these challenges faced by turtles, there is a constant focus on assessing the likely success of proposed conservation interventions to help inform decision-making processes. We develop an age-based, spatially implicit population model for the north-west shelf stock of Australia’s endemic flatback turtle Natator depressus that estimates the long-term outcomes of a range of onshore and offshore conservation interventions. Analysis of the model shows that young adults contribute most to population growth (i.e. have highest expected future reproductive success); however, this is often the most difficult life stage to manipulate in the field. Observable outcomes of interventions are often delayed for many years, especially for on shore activities (e.g. protecting eggs and hatchlings), due to late age to maturity. The potential impact of warming-induced female bias on population dynamics was also investigated. Although such bias increases population growth rates in the short term, negative effects of the bias (e.g. reduced female mating success) and negative environmental effects (e.g. reduced survival rates, habitat loss) can lead to sustained declines. Population models can rapidly assess climate change and conservation impacts on turtle dynamics and can guide monitoring efforts for real-world application.