As a followup to last week’s post on parasites, I would like to briefly highlight the role that species diversity plays in disease resistance. In healthy ecosystems with diverse communities of species, it is more likely that individual species will have resistance to a disease or parasite. In fact, transmission and infection rates of frog trematodes in pond ecosystems in California that had greater species richness were a lot lower than those for ponds with less diversity. Genetic diversity is another form of diversity that serves to increase disease resistance by increasing the chance that an individual animal will inherit adaptive genes that result in resistance. In animal populations with low genetic diversity and inbreeding, like the Florida panthers, genetic defects often surface and the populations may be more susceptible to parasites and disease. This is just yet another reason to continue protecting biodiversity before populations become small enough to be subject to inbreeding.