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1. Effects of family planning on fertility behaviour across the demographic transition.

   https://doi.org/10.1038/s41598-021-86180-8  

   Kramer, KL (January 2021, Scientific reports)
2. On‐Shelf Nutrient Trapping Enhances the Fertility of the Southern Benguela Upwelling System

   https://doi.org/10.1029/2019JC015948  

   Flynn, R. F.; Granger, J.; Veitch, J. A.; Siedlecki, S.; Burger, J. M.; Pillay, K.; Fawcett, S. E. (June 2020, Journal of Geophysical Research: Oceans)
3. Unraveling the Effects of Melt–Mantle Interactions on the Gold Fertility of Magmas

   https://doi.org/10.3389/feart.2020.00029  

   Tassara, S. (February 2020, Frontiers in earth sciences)

   null (Ed.)

   The oxidation state of the Earth’s mantle and its partial melting products exert a key control on the behavior and distribution of sulfur and chalcophile and siderophile elements between the mantle and crust, underpinning models of ore deposit formation. Whether the oxidized nature of magmas is inherited from the asthenospheric mantle source or acquired during ascent and differentiation is vigorously debated, limiting our understanding of the mechanisms of extraction of sulfur and metals from the mantle. Here, we focused on the redox-sensitive behavior of sulfur in apatite crystallized from quenched alkaline basaltic melts preserved within a peridotite xenolith from the El Deseado Massif auriferous province in southern Patagonia. We took advantage of this unique setting to elucidate the redox evolution of melts during their ascent through the subcontinental lithospheric mantle (SCLM) and grasp the inner workings of the Earth’s mantle during gold metallogenesis. Our data reveal that an initially reduced silicate melt (1FMQ 􀀀2.2 to 􀀀1.2) was oxidized to 1FMQ between 0 and 1.2 during percolation and interaction with the surrounding peridotite wall-rock (1FMQ 0 to C0.8). This process triggered changes in sulfur speciation and solubility in the silicate melt, boosting the potential of the melt to scavenge ore metals such as gold. We suggest that large redox gradients resulting from the interaction between ascending melts and the surrounding mantle can potentially modify the oxidation state of primitive melts and enhance their metallogenic fertility. Among other factors including an enriched metal source and favorable geodynamic conditions, redox gradients in the mantle may exert a first-order control on the global-scale localization of crustal provinces endowed with gold deposits. 

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4. Hidden impacts of conservation management on fertility of the critically endangered kākāpō

   https://doi.org/10.7717/peerj.14675  

   Digby, Andrew; Eason, Daryl; Catalina, Alejandro; Lierz, Michael; Galla, Stephanie; Urban, Lara; Le Lec, Marissa F.; Guhlin, Joseph; Steeves, Tammy E.; Dearden, Peter K.; et al (January 2023, PeerJ)

   Background Animal conservation often requires intensive management actions to improve reproductive output, yet any adverse effects of these may not be immediately apparent, particularly in threatened species with small populations and long lifespans. Hand-rearing is an example of a conservation management strategy which, while boosting populations, can cause long-term demographic and behavioural problems. It is used in the recovery of the critically endangered kākāpō ( Strigops habroptilus ), a flightless parrot endemic to New Zealand, to improve the slow population growth that is due to infrequent breeding, low fertility and low hatching success. Methods We applied Bayesian mixed models to examine whether hand-rearing and other factors were associated with clutch fertility in kākāpō. We used projection predictive variable selection to compare the relative contributions to fertility from the parents’ rearing environment, their age and previous copulation experience, the parental kinship, and the number of mates and copulations for each clutch. We also explored how the incidence of repeated copulations and multiple mates varied with kākāpō density. Results The rearing status of the clutch father and the number of mates and copulations of the clutch mother were the dominant factors in predicting fertility. Clutches were less likely to be fertile if the father was hand-reared compared to wild-reared, but there was no similar effect for mothers. Clutches produced by females copulating with different males were more likely to be fertile than those from repeated copulations with one male, which in turn had a higher probability of fertility than those from a single copulation. The likelihood of multiple copulations and mates increased with female:male adult sex ratio, perhaps as a result of mate guarding by females. Parental kinship, copulation experience and age all had negligible associations with clutch fertility. Conclusions These results provide a rare assessment of factors affecting fertility in a wild threatened bird species, with implications for conservation management. The increased fertility due to multiple mates and copulations, combined with the evidence for mate guarding and previous results of kākāpō sperm morphology, suggests that an evolutionary mechanism exists to optimise fertility through sperm competition in kākāpō. The high frequency of clutches produced from single copulations in the contemporary population may therefore represent an unnatural state, perhaps due to too few females. This suggests that opportunity for sperm competition should be maximised by increasing population densities, optimising sex ratios, and using artificial insemination. The lower fertility of hand-reared males may result from behavioural defects due to lack of exposure to conspecifics at critical development stages, as seen in other taxa. This potential negative impact of hand-rearing must be balanced against the short-term benefits it provides. 

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5. Differential fertility makes society more conservative on family values

   https://doi.org/10.1073/pnas.1918006117  

   Vogl, Tom S.; Freese, Jeremy (April 2020, Proceedings of the National Academy of Sciences)

   Data from the General Social Survey indicate that higher-fertility individuals and their children are more conservative on “family values” issues, especially regarding abortion and same-sex marriage. This pattern implies that differential fertility has increased and will continue to increase public support for conservative policies on these issues. The association of family size with conservatism is specific to traditional-family issues and can be attributed in large part to the greater religiosity and lower educational attainment of individuals from larger families. Over the 2004 to 2018 period, opposition to same-sex marriage and abortion was 3 to 4 percentage points more prevalent than it would have been were traditional-family conservatism independent of family size in the current generation. For same-sex marriage, evolutionary forces have grown in relative importance as society as a whole has liberalized. As of 2018, differential fertility raised the number of US adults opposed to same-sex marriage by 17%, from 46.9 million to 54.8 million. 

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