This paper revisits the relationship between population growth and economic performance by extending the Solow framework to include land as a fixed factor in a two-sector economy and migration as an endogenous adjustment. Because only agriculture uses land, effective land intensity becomes endogenous to structural transformation, declining as economies diversify. The impact of population growth therefore depends on land scarcity but is mitigated by sectoral reallocation and migration. Using a panel of 152 countries over 1960–2023 and both fixed-effects and system- Generalized Method of Moments (GMM) estimators, we show that the effect of natural population growth on per-capita income growth is highly conditional. Population growth becomes growth-reducing in agriculture-dependent and land-scarce economies, but this effect is attenuated by lower agricultural shares and land-saving technological progress. Migration further alleviates demographic pressure by reallocating labor away from land-intensive production.

We combine mathematical modeling, population growth data, archaeological survey data, and GIS analysis to project that tens of thousands of archaeological sites will be destroyed by development in Illinois by the year 2100. Climate-driven migration from less hospitable areas of the United States is likely to contribute to the growth and expansion of existing municipalities, converting millions of hectares of natural and agricultural land into urban land. A scenario of 1% annual growth over the next 80 years will impact about 55,000 sites in the state, most of which are undocumented. The damage is likely to be even more severe in other areas of the world as the global trends of population increase and urbanization accelerate the expansion of large urban areas in archaeologically rich regions.

Prey abundance is a critical determinant of tiger Panthera tigris population recovery, necessitating robust long-term monitoring to assess prey population trends and inform management interventions. We estimate the density trend of principal tiger prey populations (chital Axis axis, chousingha Tetracerus quadricornis, nilgai Boselaphus tragocamelus, sambar Rusa unicolor and wild pig Sus scrofa), in Kawal Tiger Reserve, Telangana, India, for 2010–2022. Using 28 systematically placed 4 km line transects, we observed an increase in the chital population, whereas the populations of sambar, nilgai and chousingha remained stable. The wild pig population fluctuated over this period. Despite Kawal’s designation as a tiger reserve in 2012, which enhanced protection, there is no resident tiger population in the Reserve. In the last decade, 15 tigers (of which only two were females) dispersed to Kawal from a nearby population in Maharashtra. Using prey availability models, we predicted that prey in the Reserve’s 893 km2 core area could support > 30 tigers in 2022. However, to establish a tiger population with > 30 individuals may require the reintroduction or assisted dispersal of females and enhanced connectivity with neighbouring protected areas that have source populations. This study highlights the critical importance of long-term prey monitoring for informing evidence-based conservation strategies to restore Kawal as a viable habitat for tigers.

Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae) is one of the most serious pests of rice. The variations in phytoconstituents of rice cultivars (Miniket, Cottondora Sannalu, Gobindobhog, Swarna, and Tulaipanji) that led to differences in population growth of S. cerealella were studied. Fitness of the moth was approximated in terms of mean generation time (Tc), net reproductive rate (NRR or R0), intrinsic rate of population increase (rm), etc. Considering potential fecundity (Pf), growth rates, mortality coefficient (MC), and expected population size in the second generation (PF2), we classified the susceptibility of the rice cultivars to S. cerealella in the order as M > C > G > S > T. This was despite the higher concentrations of all the tested primary metabolites (PMs) in C and T. The least susceptibility of T and lower susceptibility of C than M can be attributed to their higher levels of secondary metabolites (SMs). M was highly susceptible due to its lowest SM content and sufficient levels of PMs. Now, G and S contained lower amounts of SMs, but they were moderately susceptible owing to the lower PM content. This emphasises the role of SMs, such as phenols, flavonoids, tannins, saponins, alkaloids, phytates, and oxalates, in determining the susceptibility of crop cultivars. Although none of the rice cultivars were entirely resistant, it can be stated that Miniket requires more protection measures against S. cerealella during storage than the others.

Seabirds are excellent ecosystem indicators and are amongst the most threatened taxa globally. Aldabra Atoll, Seychelles, supports significant breeding colonies of seabirds, especially red-footed boobies Sula sula. The population was surveyed by boat during 1968–1969 and in 2000, over which period the population grew from c. 6,500 to 10,000 breeding pairs. In 2022–2023, we monitored five subcolonies across Aldabra to determine breeding phenology and breeding success. In August 2022 and February 2023, we surveyed the atoll-wide population using the boat-based survey methodology followed in earlier studies. We also carried out unmanned aerial vehicle (UAV) surveys in February 2023 to compare the results with the boat-based counts and to quantify inland colonies undetectable by boat. Boat surveys revealed that Aldabra’s red-footed booby population had grown to 36,720 pairs by 2023, an increase that is intrinsically possible based on our population model but only if the much lower count in 2000 was an underestimate. The UAV and boat counts were closely aligned in our study, and aerial images captured a similar number of nests to boat surveys for shoreline colonies. However, UAV surveys revealed several undocumented inland colonies. An additional 5,574 inland breeding pairs of red-footed boobies were counted from images captured inland during aerial surveys in the 2023 wet season, bringing the atoll-wide population to at least 45,817 pairs. We recommend UAVs for surveys of large, conspicuous seabird species at low-lying mangrove colonies. Our study highlights the global importance of Aldabra as the most significant red-footed booby colony in the Indian Ocean and possibly the world.

Population growth was a pivotal issue in the United Nations during its first decades. The global population was growing steeply, and most of this growth took place in the formerly colonized states. Population trends were framed as an aspect of development and became object of extensive international activities, outside the UN and within. The paper explores the population discourse of those years with a focus on the UN and on the relationship with international law. It traces, firstly, the UN documents engaging directly with population growth and aiming to influence national population policies. Secondly, the paper suggests that the framing of population growth as problem of development stressed its causal role for poverty and food insecurity. The struggles for a New International Economic Order coincided with the international focus on population growth, partly with competing interpretations of reasons for global economic inequality. Thirdly, the paper suggests that the activities within the UN played a central role in shaping the discourse. While the activities of governments and private organizations were significant, it was through the authority of the UN that the development-population-nexus achieved such dominance.

Amur honeysuckle [Lonicera maackii (Rupr.) Herder] is an aggressive invader of forests throughout the eastern United States. While self-pollination has been identified as an important trait of invasive plant species, this trait is understudied, and L. maackii is anecdotally described as lacking this characteristic. To examine the ability of L. maackii to self-pollinate, we selected 171 individual shrubs distributed across nine sites. Each site was grouped into one of three invasion types: heavy, light, and sprouting (sites on which a basal cutting treatment previously occurred, but L. maackii was allowed to reestablish). We compared the number of berries, seeds per berry, and seed germination rates of self- and open-pollinated flowers by pairing branches covered with pollination bags before flower emergence with uncovered branches on the same individual shrub. Out of 171 individuals, 48 produced berries from self-pollination within pollination bags (28%), with 48% of bagged branches exhibiting some degree of necrosis or chlorosis, presumably due to increased temperature and humidity. Berries from self-pollination produced 1.5 ± 1.4 (mean ± 1 SD) seeds per berry, whereas berries resulting from open pollination produced 3.3 ± 1.5 seeds per berry. In a germination trial, 47.3% of self-pollinated seeds germinated compared with 41.7% of open-pollinated seeds. This study has shown that L. maackii can self-pollinate and set viable seed, providing the species with an important mechanism to increase population abundance during the early stages of invasion.

This study investigates the linkages between changes in agricultural land use and population growth in India. We have employed long-term time series and a panel dataset of 1869 samples (267 districts × 7 time points from 1961 to 2021) to determine this. We theorize that there is an inverted “U-shape” relationship between changes in population growth and agricultural land. Our findings suggest a positive impact of population growth on the change in cultivated land. However, this relationship was not static during 1961–2021. We found a two-stage split relationship with a breakpoint in 1981. Prior to the 1980s, there was a 12% expansion in cultivated land in response to a unit increase in population growth. During the post-1980s, with a unit decline in population growth, there was a 5% reduction in cultivated land. The findings were reaffirmed through several robustness checks: analyses using alternative outcome variables, alternative break points in a segmented regression model, and spatial modeling. From a policy perspective, this study advances the need for the reduction of population growth rate in high-fertility states and the adoption of superior and green technology for agricultural intensification and diversification to stop cropland expansion at the cost of environmental sustainability.