The differences in the richness and prevalence of human pathogens among different geographical locations have ramifying consequences for societies and individuals. The relative contributions of different factors to these patterns, however, have not been fully resolved. We conduct a global analysis of the relative influence of climate, alternative host diversity and spending on disease prevention on modern patterns in the richness and prevalence of human pathogens. Pathogen richness (number of kinds) is largely explained by the number of birds and mammal species in a region. The most diverse countries with respect to birds and mammals are also the most diverse with respect to pathogens. Importantly, for human health, the prevalence of key human pathogens (number of cases) is strongly influenced by disease control efforts. As a consequence, even where disease richness is high, we might still control prevalence, particularly if we spend money in those regions where current spending is low, prevalence is high and populations are large.
CITATION: Maas, B. et al. 2020. Academic leaders must support inclusive scientific communities during COVID-19. Nature Ecology and Evolution, doi:10.1038/s41559-020-1233-3.
Predation is a fundamental ecological process that shapes communities and drives evolutionary dynamics. As the world rapidly urbanizes, it is critical to understand how human perturbations alter predation and meat consumption across taxa. We conducted a meta-analysis to quantify the effects of urban environments on three components of trophic ecology in predators: dietary species richness, dietary evenness and stable isotopic ratios (IRs) ( δ 13 C and δ 15 N IR). We evaluated whether the intensity of anthropogenic pressure, using the human footprint index (HFI), explained variation in effect sizes of dietary attributes using a meta-regression. We calculated Hedges’ g effect sizes from 44 studies including 11 986 samples across 40 predatory species in 39 cities globally. The direction and magnitude of effect sizes varied among predator taxa with reptilian diets exhibiting the most sensitivity to urbanization. Effect sizes revealed that predators in cities had comparable diet richness, evenness and nitrogen ratios, though carbon IRs were more enriched in cities. We found that neither the 1993 nor 2009 HFI editions explained effect size variation. Our study provides, to our knowledge, the first assessment of how urbanization has perturbed predator–prey interactions for multiple taxa at a global scale. We conclude that the functional role of predators is conserved in cities and urbanization does not inherently relax predation, despite diets broadening to include anthropogenic food sources such as sugar, wheat and corn.
Wildlife respond to human presence by adjusting their temporal niche, possibly modifying encounter rates among species and trophic dynamics that structure communities. We assessed wildlife diel activity responses to human presence and consequential changes in predator-prey overlap using 11,111 detections of 3 large carnivores and 11 ungulates across 21,430 camera trap-nights in West Africa. Over two-thirds of species exhibited diel responses to mainly diurnal human presence, with ungulate nocturnal activity increasing by 7.1%. Rather than traditional pairwise predator-prey diel comparisons, we considered spatiotemporally explicit predator access to several prey resources to evaluate community-level trophic responses to human presence. Although leopard prey access was not affected by humans, lion and spotted hyena access to three prey species significantly increased when prey increased their nocturnal activity to avoid humans. Human presence considerably influenced the composition of available prey, with implications for prey selection, demonstrating how humans perturb ecological processes via behavioral modifications.
Protected areas largely now exist as coupled natural-human ecosystems where human activities are increasingly forcing wildlife to adjust behaviors. For many ungulate species that rely on protected areas for their persistence, they must balance these anthropogenic pressures amid natural regulators. Here, we investigated the pressures exerted from humans and livestock, apex predators, and within guild competitors on ungulate co-occurrence patterns in a fragile protected area complex in West Africa. Specifically, we used multi-species occupancy modeling to quantify co-occurrence amongst four ungulates (Tragelaphus scriptus, Redunca redunca, Kobus kob, Phacochoerus africanus) and applied structural equation models to discern the relative contributions of pressures on co-occurrence patterns. We observed a strong spatial gradient across with higher co-occurrence in the wetter western portion of our ~13,000 km2 study area. Co-occurrence patterns among ungulate dyads ranged from 0.15-0.49 with the smallest body sized pair showing highest levels of sympatry, warthog and reedbuck. We found that anthropogenic pressures, namely cattle had the greatest effect in reducing sympatry among wild ungulate in comparison to African lions that also induced negative effects. Humans, hyenas, and competitors showed positive effects on ungulate co-occurrence. In a region of the world ongoing rapid socio-ecological change with increasing threats from climate and environmental instability, protected areas in West Africa represent a major safeguard for wildlife and human livelihoods alike. Our findings highlight the need for effective interventions that focus on large carnivore conservation, habitat restoration, and containment of livestock grazing to promote the coexistence of biodiversity and socio-economic goals within the region.
Species loss can result in the subsequent loss of affiliate species. Though largely ignored to date, these coextinctions can pose threats to human health by altering the composition, quantity and distribution of zoonotic parasites. We simulated host extinctions from more than 1300 host-parasite associations for 29 North American carnivores to investigate changes in parasite composition and species richness. We also explored the geography of zoonotic parasite richness under three carnivore composition scenarios and examined corresponding levels of human exposure. We found that changes in parasite assemblages differed among parasite groups. Because viruses tend to be generalists, the proportion of parasites that are viruses increased as more carnivores went extinct. Coextinction of carnivore parasites is unlikely to be common, given that few specialist parasites exploit hosts of conservation concern. However, local extirpations of widespread carnivore hosts can reduce overall zoonotic richness and shift distributions of parasite-rich areas. How biodiversity influences disease risks remains the subject of debate. Our results make clear that hosts vary in their contribution to human health risks. As a consequence, so too does the loss (or gain) of particular hosts. Anticipating changes in host composition in future environments may help inform parasite conservation and disease mitigation efforts.
Gentrification operates as a social driver of health that can increase tick‐borne disease (TBD) risk for communities of color through either population displacement or land‐use change. Research on the emergence of TBDs in urban environments has primarily focused on the ecological processes of urban landscapes that facilitate favorable habitats for host reservoirs and tick vectors. However, neglecting to view infectious disease risk from a socioecological framework will continue to result in policies and planning that disadvantage communities of color. Using Lyme disease as a case study, we integrated elements of environmental epidemiology, ecology, public health, and urban planning to propose pathways of gentrification as a socioecological process with public health implications. By drawing connections between urban ecology, urban planning, and environmental racism, we seek to bring awareness to disease ecologists, policy makers, and public health managers on the potential role of gentrification as a driver of tick‐borne pathogen exposure. Front Ecol Environ 2022;
