A world without borders – why biodiversity matters

Emperor Justinian by Meister von San Vitale in Ravenna. Image in public domain.

The news is still full of the fires in Indonesia and the resulting smog in Singapore and Malaysia – unfortunately air pollution doesn’t stop at national borders. Also unfortunately, Indonesia is not a party to the Association of South East Asian Nations (ASEAN) Agreement on Transboundary Haze Pollution, although it is being pressed at this week’s ASEAN meeting to sign on.

Another issue that doesn’t stop at borders is water: all around the world, water is drawn from rivers or aquifers for human or industrial use or agriculture, and pollutants pumped in, without regard for the trees that depend on it or even the people on the other side of the hill who need clean water.

And animals can travel, and with them disease: bubonic plague is carried within infected fleas, which travel on rodents such as rats and mice, which travel handily from port to port on ships. Plague has spread across the world in this way, blithely disregarding national boundaries and attempts by various governments to regulate what comes into their country. In the rather quaint words of the Wikipedia entry describing the Justinian plague:

In the spring of 542, the plague arrived in Constantinople, working its way from port city to port city and spreading through the Mediterranean, later migrating inland eastward into Asia Minor and west into Greece and Italy. Because the infectious disease spread inland by the transferring of merchandise through Justinian’s efforts in acquiring luxurious goods of the time and exporting supplies, his capital became the leading exporter of the bubonic plague.

So what does this have to do with biodiversity? Well, biodiversity, like clean air, clean water, and healthy soil, is one of the bases of a robust ecosystem.

Genetic diversity within a species helps make that species robust, by ensuring that individuals aren’t mating with close relatives and intensifying weaknesses. Geographic diversity within a species helps make that species robust by allowing the species to develop a reasonably-sized population and spread widely enough to be secure.

And species diversity within an ecosystem helps make the entire ecosystem robust, by limiting the spread of disease within any given species and protecting against the results of a sudden drop in the population of any one species. Monocultures are inherently vulnerable to pests and diseases, as Henry Ford discovered: this is the reason for the massive spraying of pesticides on all large-scale agriculture. And this is a losing game, since the life cycle of pests is much shorter than that of the pesticides, and so the pests are evolving faster than we can keep up with.

Geographic diversity of species will always cross borders, since species live in preferred habitats, whereas national or state borders are determined by history and politics. As a result, anything we do will impact not only within our own borders, but on our neighbours and ultimately around the world, just as our neighbours’ activities will impact on us.

So we would do well to do our utmost to maintain biodiversity, if for no other reason than because our food depends on it.

[Featured image: Limited visibility due to smog in Aceh, picture taken on the track road Medan – Banda Aceh, Pidie Jaya District. Licensed under the Creative Commons Attribution-Share Alike 4.0 International. Image added after original publication of this blog post]