Consequences of non-intervention for infectious disease in African great apes

Infectious disease has recently joined poaching and habitat loss as a major threat to African apes. Both "naturally" occurring pathogens, such as Ebola and Simian Immunodeficiency Virus (SIV), and respiratory pathogens transmitted from humans, have been confirmed as important sources of mortality in wild gorillas and chimpanzees. While awareness of the threat has increased, interventions such as vaccination and treatment remain controversial. Here we explore both the risk of disease to African apes, and the status of potential responses. Through synthesis of published data, we summarize prior disease impact on African apes. We then use a simple demographic model to illustrate the resilience of a well-known gorilla population to disease, modeled on prior documented outbreaks. We found that the predicted recovery time for this specific gorilla population from a single outbreak ranged from 5 years for a low mortality (4%) respiratory outbreak, to 131 years for an Ebola outbreak that killed 96% of the population. This shows that mortality rates comparable to those recently reported for disease outbreaks in wild populations are not sustainable. This is particularly troubling given the rising pathogen risk created by increasing habituation of wild apes for tourism, and the growth of human populations surrounding protected areas. We assess potential future disease spillover risk in terms of vaccination rates amongst humans that may come into contact with wild apes, and the availability of vaccines against potentially threatening diseases. We discuss and evaluate non-interventionist responses such as limiting tourist access to apes, community health programs, and safety, logistic, and cost issues that constrain the potential of vaccination.     

Soil microarthropods in non-intervention montane spruce forest regenerating after bark-beetle outbreak

We studied Oribatida and Collembola in an old-growth Norway spruce (Picea abies) forest that suffered a massive bark beetle (Ips typographus) outbreak in the 1990s and gradually decayed. It was left to regenerate naturally without human intervention. There was a high abundance of a few tolerant species and lower numbers of sensitive silvicolous ones. The most dominant species were Tectocepheus velatus, Platynothrus peltifer and Isotomiella minor. Although the details, which determine the identity of successful species, remain unknown, parthenogenesis, high reproduction rate and detrito- or detritofungivorous feeding were the common features of the most dominant species in our study. Trait assessment showed an overall predominance of parthenogenesis and high abundance of detritivorous oribatids. The soil functions connected with Oribatida and Collembola seem to be still affected by the bark-beetle outbreak and our results indicate that the disturbance caused important changes in the functioning of the whole soil ecosystem.