Video is a brief summary of this post: Homegrown Diversity and Infectious Diseases

You might think that a garden full of native plants, thicker on the ground and under the trees, jumbled together in profusion, might be a better habitat for disease-carrying ticks, bugs, and mice than a closely cropped lawn of turfgrass in a neat suburb with lots of "Garden Center" landscaping. Intuitively, the neat and managed neighborhood looks like the sort of place where infectious diseases couldn’t thrive. The experience of the last few decades in southern New England would suggest otherwise!

Lyme Disease, a bacterial infection transmitted by the bite of the black-legged deer tick, has dramatically spread in the region over the last 50 years. The bacteria, the tick vector, and the natural hosts – deer, mice, and birds – were all present before humans arrived in North America. The explosion in human cases, first detected in the 1970s, was fueled by human environmental changes. Development, suburbanization, the introduction of invasive plants, and habitat fragmentation disrupted the native biome.

The inverse relationship between biodiversity and transmission of infectious diseases is an established ecology concept called “The Dilution Effect”. As biodiversity declines the most able species that take advantage of this are those that tend to reproduce rapidly, adapt quickly to denuded habitat, and also tend to be good hosts for infectious organisms.

What would limit this march of infectious diseases into new regions? Biodiversity! Imagine a mouse or a deer or a tick or a mosquito migrating into a new habitat. If a place is already full of a healthy mix of native wildlife (everything from bugs to birds to mammals) it’s harder for an outsider species to take over. There’s just too much competition from the locals. The best way to crowd our neighborhood with abundant neighbors is to create native environments favored by locally adapted species.