Landscape heterogeneity is not just good for birds and bees

By Dave Abson

It struck me that my previous post might possibly make me seem slightly clownish (I guess the balloon modelling did not help?). So here is a little bit of a scientific corrective:

It is now relatively well established that land-use diversity/habitat heterogeneity in agro-ecosystems plays a key role in the conservation of biodiversity, the maintenance of ecological functions and the provision of multiple ecosystem services. There is therefore a compelling argument that societies should encourage diverse agricultural landscapes. However, agricultural landscapes are generally not managed by societies. Farmers, have their own sets of priorities in the management of their land, primary amongst them is the need to maintain a viable and stable income. In a recent paper we explored the relations between agricultural land-use diversity and the level, volatility and resilience of farmed incomes over a period of 44 years in lowland agricultural landscapes in the UK.

Employing portfolio theory (from the finance literature) we found that there was a strong linear trade-off between the expected farmed income and the volatility of that income across landscapes. The stability and economic resilience of farmed incomes increased with increasing land-use diversity. From this we conclude that land-use diversity may have an important role in ensuring resilient agricultural incomes in the face of uncertain future market and environmental conditions, and that this economic resilience can be achieved while maintaining aggregate yield across landscapes. So what’s good for the goose (or assemblage of farmland bird species… see future post) may also be good for the gander (farmer).

The paper is open access and can be downloaded from here.

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2 thoughts on “Landscape heterogeneity is not just good for birds and bees

  1. All hunky dory – cf mixed cropping in areas of uncertain rainfall – and no great eye opener. What is not considered is the difficulty of marketing, needed to create the ‘income’, of a diversity of crops/enterprises. 2 cows, little milk, 20 cows a real income with economies of scale etc. so diversity may reduce risk but it almost certainly reduces income. Use of labour, avoidance of peaks, may also be an advantage of diversity … Lots to consider …

  2. Dear Jeremy,

    perhaps I should have made this more clearly, the analysis is based on actual land use patterns and livestock stocking densities, not some theoretical ideal diversifications (as I know has been done elsewhere with MPT). The fact that these land use/cropping patterns exist strongly suggest that they provide sufficent economies of scales to provide farmers with sufficent profits (this is what matters not income), otherwise they would not exist. I agree that increased diversity is also likely to have some negative affect on profits, but this is kind of my point, there is a trade-off between aggregate income and the stability of that income. In the UK it is often the wild annual swings in income that force smaller farms out of the sector.

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