Saturday, May 16, 2009

Agave, Bats and Evolution

Just a quick thought this morning on the interconnections between all things.

I’m reading a book of essays called Farming and the Fate of Wild Nature: Essays in Conservation-based Agriculture, and just finished an interesting article by Gary Paul Nabhan on the agave industry. The sap from the agaze plant is used in the making of Tequila, and as such, it is farmed extensively in Mexico.

There are several different agave species, but just one, the blue agave, is responsible for almost all tequila production, and in fact much of it is made from one particular variety of the blue agave or even clones of one individual plant. This greatly limits the genetic variability in the agaves grown commercially, making them much more susceptible to catastrophic disease. They are also generally planted in dense monocultures, without the disease buffers that intercropping with other row crops would give, and without wild margins or barriers that would do the same.  Furthermore, the commercially-grown agave is rarely allowed to flower, thus preventing local bat species from pollinating them, both affecting the stability of bat populations and the ability of the blue agave plants to evolve natural disease resistance along with their pathogens.

This is all fairly straightforward, but what interested me was the way the article framed the relationships between economic cycles and social behavior with not only an agricultural enterprise but also the general ecology of a large part of Mexico and parts of the United States. There was a huge growth in demand for tequila in the 80’s and 90’s (which I personally remember and took some small part in; I am still fond of the occasional margarita) which fueled a boom in agave production. This led to incentives to grow more and more plants in dense, monocultural stands of the quick-maturing blue agave clone. A disease began to spread through the plantations, eventually affecting a large percentage of all agaves grown commercially.

During the boom cycle, growers are encouraged to maximize production as quickly as possible. During the bust cycle, from disease or loss of demand and anything else leading to economic difficulties for growers, there is not the financial ability or will to use more long-term sustainable practices like selecting quality, genetically diverse plants, using intercropping, or allowing some plants to evolve naturally through cross-pollination and natural selection.

It’s sort of like if you win you lose, and if you lose you lose, and every step contributes to the loss of ecological diversity (in wild populations and crops) and economic instability. I would argue that the boom cycles, when things are relatively flush, are the times to get thoughtful about what you’re doing and think of the long-term prospects of your industry and your community, rather than as a time to exploit the cycle for what is often a very brief window of significant growth. This takes education and a sense of personal responsibility to the land and to your community, as well as a long perception of time.

I just wanted to make a comment on the ecology between human economy and natural systems (really we are all enmeshed in one big natural system, in this case from office parties in Manhattan restaurants to bat populations and wild agave species in Mexico) and ended up on a bit of a rant, but that is how things will go sometimes. Anyway, I just thought it was interesting.


dldeprez said...

This is in keeping with the theme with which I teach all my science courses in high school biology, Earth systems, and environmental science. The abstract concept of biodiversity is not hard to teach even freshmen if you use examples like the agave industry to show how biodiversity contributes to stability of interactions in the face of perturbations and efficiency in the utilization of resources. What you are reading really is an argument for multi- as opposed to mono-...culture. Go CSA!

/|\^..^/|\ said...

great post! ... the bats-agave-tequila issue has become even more complicated with the recent boom in agave nectar sales ... i've written an article about it on my blog:’t-have-agaves-without-bats/

Anonymous said...

J'ai appris des choses interessantes grace a vous, et vous m'avez aide a resoudre un probleme, merci.

- Daniel