Today I'll be commenting on the 10th Permaculture principle which is to "Use & Value Diversity" (you can find my discussion of the other 9 principles here).

There are some obvious and not so obvious reasons to use and value diversity. Nature contains alot of diverse types of animals and plants but we have not done a good job of conserving that bio-diversity so it makes sense to use & value diversity because these species are never coming back and we are losing valuable ecological and cultural resources when a species is lost (either by crowding them out with development or because corporate interests are trying to control the seed trade so that traditional seeds are dropped in favor of corporate seeds).

Another reason we might use and value diversity is because our agricultural landscape often consists of large expanses of monoculture that may not work so well in a future with less energy or a changing climate. Diversity in our agricultural landscapes can help us be more resilient in the face of these major challenges. This would mean a return to more diversified farming operations that includes several crops, animals, and probably more agro-forestry type approaches where we mix animals, trees, and crops.

Diversity can help to make systems more stable and resilient. If one pest or disease comes into a monocultural operation it has a greater chance of wiping out a farm's crop than if we have at least two different types of crops we are growing. The more intermixing of these crops might also prevent the spread of pests and diseases in the same crop.

Diversification in investment portfolios can help to preserve wealth in the face of downturns in specific industries. The oil & gas industry has lower barrel prices that would have had a major impact on investors with all of their holdings in this sector. Better to have investments in several industries whose economic performance is not strongly correlated.

Diversity in the workplace can also have many benefits. Under the appropriate conditions, the wealth of perspectives and knowledge represented by a diverse workforce can help the company exhibit a sort of hybrid vigor that can lead to outperformance of companies with less diversity.

The stability that diversity produces in ecosystems is not a simple function of the number of different species in a given region. More important is the number and strength of connections between the elements in the ecosystem. You can have fewer species, but if those species have lots of functional interconnections, then this results in more ecosystem stability than many species with few functional interconnections between them (see the Integrate Rather Than Segregate principle also).

So the way to use diversity to increase stability and resilience is not just to add more species, but to make sure that each species offers and receives services from the other species in the mix. Instead of just putting in different plants for the sake of having a more diverse garden, you select your plants so that they are good companions to the other plants, in the right shade relationships, etc...

In agriculture we often prefer simpler monocultural systems because they are easier to manage (but less stable). Too much diversity can lead to unmanageable complexity so we must take some care to balance diversity against simplicity. Often a diverse planting will simplify on its own to fewer elements that work together better.

David Holmgren also talks about diversity in the context of experimenting to see what works. If you don't try it you'll never know. Using this strategy, however, we must also be prepared to cull when we find that one of our species is not working. Diversity and culling often go together to ensure tight ecosystems.

The concept of diversity has many meanings and subtleties when you research it more. Let this principle be a reminder to spend more time thinking about how much diversity is manageable, how that diversity is to be integrated into the whole, what types of benefits we might gain from adding or preserving diversity, and what diversity lessons can we learn from nature.