How Does Species Diversity Affect Disease Transmission?
Species diversity impacts disease transmission primarily through two mechanisms: the dilution effect and the amplification effect.
1. Dilution Effect: This occurs when increased species diversity reduces the risk of disease transmission. In diverse ecosystems, the presence of multiple hosts can dilute the impact of a pathogen. For instance, in a forest with various animal species, a pathogen that affects only one or a few species will have limited opportunities to spread.
2. Amplification Effect: Conversely, in some cases, high species diversity can enhance disease transmission. This happens when additional species serve as reservoirs or carriers, thereby increasing the pathogen's chances of spreading. An example is the role of multiple bird species in the spread of West Nile Virus.
