I've spent most of the last 8 months in a Mexican village on the shores of Mexico's largest lake - Lake Chapala.  My parents retired here here over a decade ago, and I've been helping take care of my mother who sadly had a terminal illness.  Living in a small village was a dramatic change for a big city kind of guy, but the experience was rich on many levels.  And as I'm always on the lookout for ideas on how to improve urban sustainability and biodiversity I managed to learn some urban design lessons while here that should be applied in large cities.

The sustainable design visible in Ajijic results, in fact, from being behind the times. Modern, efficient construction techniques are only beginning to filter into the structure of the town.  Roads are generally not paved with smothering asphalt or cement, but instead with stones hand placed on a natural foundation of dirt.  These stones are quarried locally, are put into place without any mortar, and provide a very durable and long-lasting surface that is permeable to rain.  The roots of trees and other vegetation can grow nicely under the streets.  When changes are required the stones are simply dug up and rearranged.  An added advantage to these natural streets is that they do not encourage high speed auto traffic.  The roads are a bit rough for cars, so drivers generally drive slowly.  Traditional construction techniques extend into housing.  Most everything in this village is built from bricks and clay tiles.   Cement is used for the underlying structures of the houses (and for mortar, as well), but generally speaking there are few non-biodegradable materials used.  When local houses are abandoned, they sort of dissolve back into nature. 

Another striking thing about Ajijic is the proliferation of green on all sides.  There are gardens and trees wherever you look, and the ubiquitous stone walls are generally covered with flowering vines.  Biodiversity, already very high in this part of Mexico, is astounding.  Although many non-native species of plants are grown around houses, birds of many colors, small animals and insects are in abundance.  The surrounding mountains, largely undeveloped and disturbed only by some traditional agriculture, are also sources of beauty and biodiversity. 

Most large cities don't have the nature-rich, mountainous backdrop of Ajijic (nor the near-ideal climate), but there is no reason they can't adopt the sustainable and biodiversity-enriching practices I see around me here. Many streets and alleyways in U.S. cities could be, at least in part, made from permeable, natural pavements.  I mention the U.S. because in Europe permeable streets are much more common.   Both European and American cities can strengthen efforts to increase the variety of trees and shrubs they plant, choosing those varieties that encourage and nurture wildlife.  Spaces that generally are not green, such as the walls of buildings, can be retrofitted to support vines and other plants and provide nesting sites for birds.  These may seem like radical ideas, but here in Ajijic they surround you on all sides.  I will miss this corner of Mexico.