Search for: All records

Tropical cyclones (e.g., hurricanes and tropical storms), are considered one of the world's most destructive climatological forces, causing substantial damage especially in urban areas. However, for some arid ecosystems, tropical cyclones represent natural disturbance events, providing important sources of fresh water that support ecosystem functioning. For subsistence populations living in these regions, it is unclear whether they experience these events negatively due to the associated damages or positively within a predictable disturbance regime. Here, we assess these phenomena with traditional ranchers from Baja California Sur, Mexico, following Hurricane Kay (September 2022). We find that despite significant damage caused by the hurricane, nearly the entire sample perceived this tropical cyclone event as a net positive on their lives. This traditional ranching population has a culture that is adapted to the seasonal tropical cyclone disturbance regime, and expects extreme rain events annually to support ecosystem functioning, and therefore their economic livelihoods. To these ranchers, the climate shock is not when the hurricanes come, but rather, when hurricanes do not come. We situate our results within a disturbance ecology framework, highlighting the role of increasing aridity and probability of drought in the North American Arid West. 

Abstract Climate-induced drought jeopardizes future access to sufficient energy sources for many people reliant on firewood, especially those underrepresented in forest management decision-making. To identify where interventions might be most effective in facilitating self-determination and sustained firewood harvest, we investigate the case of Diné firewood harvesters. Using data from surveys, interviews and participant observations, we articulate who uses firewood and why, what the costs of firewood are, and who imposes those costs. Reducing both the cost and need for firewood for the Diné and others would support energy sovereignty by facilitating sustained access to firewood. 

While it is commonly assumed that farmers have higher, and foragers lower, fertility compared to populations practicing other forms of subsistence, robust supportive evidence is lacking. We tested whether subsistence activities—incorporating market integration—are associated with fertility in 10,250 women from 27 small-scale societies and found considerable variation in fertility. This variation did not align with group-level subsistence typologies. Societies labeled as “farmers” did not have higher fertility than others, while “foragers” did not have lower fertility. However, at the individual level, we found strong evidence that fertility was positively associated with farming and moderate evidence of a negative relationship between foraging and fertility. Markers of market integration were strongly negatively correlated with fertility. Despite strong cross-cultural evidence, these relationships were not consistent in all populations, highlighting the importance of the socioecological context, which likely influences the diverse mechanisms driving the relationship between fertility and subsistence. 

To address claims of human exceptionalism, we determine where humans fit within the greater mammalian distribution of reproductive inequality. We show that humans exhibit lower reproductive skew (i.e., inequality in the number of surviving offspring) among males and smaller sex differences in reproductive skew than most other mammals, while nevertheless falling within the mammalian range. Additionally, female reproductive skew is higher in polygynous human populations than in polygynous nonhumans mammals on average. This patterning of skew can be attributed in part to the prevalence of monogamy in humans compared to the predominance of polygyny in nonhuman mammals, to the limited degree of polygyny in the human societies that practice it, and to the importance of unequally held rival resources to women’s fitness. The muted reproductive inequality observed in humans appears to be linked to several unusual characteristics of our species—including high levels of cooperation among males, high dependence on unequally held rival resources, complementarities between maternal and paternal investment, as well as social and legal institutions that enforce monogamous norms.