Is biodiversity good for us? In many ways, this is a stupid question because at some point, losing species that we use directly will obviously impact us negatively — think of food crops, pollination and carbon uptake.
But how much can we afford to lose before we notice anything bad is happening? Is the sort of biodiversity erosion we’re seeing today really such a big deal?
One area of research experiencing a surge in popularity is examining how variation in biodiversity (biowealth1) affects the severity of infectious diseases, and it is particularly controversial with respect to the evidence for a direct effect on human pathogens (e.g., see a recent paper here, a critique of it, and a reply).
Controversy surrounding the biodiversity-disease relationship among non-human species is less intense, but there are still arguments about the main mechanisms involved. The amplification hypothesis asserts that a community with more species has a greater pool of potential hosts for pathogens, so pathogens increase as biodiversity increases. On the contrary, the dilution hypothesis asserts that disease prevalence decreases with increasing host species diversity via several possible mechanisms, such as more host species reducing the chance that a given pathogen will ‘encounter’ a suitable host, and that in highly biodiverse communities, an infected individual is less likely to be surrounded by the same species, so the pathogen cannot easily be transmitted to a new host (the so-called transmission interference hypothesis).
So I’ve joined the ecological bandwagon and teamed up yet again with some very clever Chinese collaborators to test these hypotheses in — if I can be so bold to claim — a rather novel and exciting way.
Our new paper was just published online in Ecology: Warming and fertilization alter the dilution effect of host diversity on disease severity2. Read the rest of this entry »