Shifting baselines and the impacts of meat production

Typical chicken feet snack in China
Typical chicken feet and gizzards snack in China

Visiting China last year got me thinking about meat. Part of this was because as a vegetarian it was a fun daily challenge to find meat-free food often involving 2 -3 hours wandering around huge, smog-filled cities. Meat in China is ubiquitous and best summed up by the old joke that “Chinese people eat everything with legs except tables, everything with wings apart from planes.” I really admire the Chinese attitude of eating everything from duck’s tongue, to chicken’s feet, but looking at the graph below it is obvious that the amount of meat in Chinese diets is also increasing rapidly.

Changes in per capita meat consumption in China. data taken from FAo and can be found here.
Changes in per capita meat consumption in China from 1961-2014. Data is taken from the FAO statistics database and can be found here.

As with most countries meat consumption in China is made up of a mixture of imported and domestically produced meat. This means that the ecological consequences of diets in China and nearly all countries are felt at home as well as abroad. I have written previously on the impacts of meat consumption for biodiversity and why I think ecologists should eat less meat. Some comments on that post pointed out that not all meat has the same environmental cost. This is undoubtedly true. However, I’m not sure that these costs are quite as simple as I, and others, initially thought.

The comparison that is often made to highlight differed impacts is the difference meat production in tropical and temperate part of the world. Tropical cattle farming often involves clearance of forest or savannah for production of feed and grazing land. In contrast temperate cattle often graze on centuries old pastures with supplementary feed imported from other regions. Therefore the forest clearance associated with tropical cattle production must make it worse, right? Well, yes and no.

Firstly just because the loss of ecosystems in temperate regions happened centuries or millennia ago doesn’t mean that current farming has no impact. Grazing stops ecological succession and recovery of ecosystems that may otherwise be forest. However, the fact the conversion from natural to managed systems happened such a long time ago means that this impact is less obvious. Most Europeans live somewhere that has had widespread agriculture for generations and so this is perceived as being perfectly normal. Traditional agricultural landscapes, which elsewhere would be seen as degraded ecosystems, are even seen as being in need of protection in the EU. This raises potentially interesting questions such as “Are cultural services prone to shifting baseline syndrome? And if so, couldn’t massive loss of biodiversity occur without any long term effects on these cultural services?”

If we accept that both past and present destruction of ecosystems have a negative effects on biodiversity and some ecosystem services then this raises the question of where these impacts are likely to be greater. If we think that species with small populations or range sizes are the species of highest conservation priority then it is clear that impacts in the tropics are likely highest. These regions have more species and more of these species have small ranges. We could of course argue for different methods of prioritisation for biodiversity but for the moment I’ll just stick with this one.

When it comes to carbon emissions and sequestration the picture is less clear. Though tropical forests tend to have very high carbon stocks plenty of intact temperate forests have similar carbon density (see below). As such any regrowth of forests in temperate regions represents a potentially important contribution to climate change mitigation. How other ecosystem services are affected is unclear.

forest carbon
Global forest site data for above-ground biomass carbon in relation to latitude (north or south). Points are values for individual or average of plots, and bars show the range in values at a site. Taken from Keith et al 2009

I am obviously not proposing that cattle ranching in the tropics is a good thing. However, I think we need to stop kidding ourselves that meat production doesn’t have profound impacts on ecosystems – it clearly does, whether your beef comes from Britain or Brazil. The best way to reduce this impact is by eating less of the stuff.

Land sharing vs land sparing – meeting agricultural and biodiversity goals

Earlier this month I went to the 2012 European Congress of Conservation Biology where the best session by far was one on land sharing vs land sparing (see a summary of the session by Joern Fischer here). This session was inspired by the Science paper by Ben Phalan and resulting back-and-forth.

The main idea behind the paper was that with increasing global population we need to increase food production. We can either do this by increasing the area of agriculture or intensifying production in the agricultural land we currently use. To limit the impact of both these options on biodiversity we could use wildlife friendly farming, termed land sharing. Another option is to spare natural ecosystems from conversion in the case of intensification, termed land sparing.

Thus land sharing aims to integrate goals for food production and biodiversity protection on the same land, while land sparing aims to separate intensive farming from protected ecosystems at the larger scale (A caricature of this continuum is provided below) .

Conceptual diagram of the land sparing-land sharing continuum, taken from the Fischer et al paper found here

Phalan et al took these options and tested their potential effects on bird and tree populations in Ghana and Northern India by looking at landscapes which represented these differing strategies. Using this data they plotted yield against species density to define how populations may change with increased yield. These changes allowed them to classify species as ‘losers’ or ‘winners’ following agricultural conversion as well as defining the land use options most likely to be beneficial for maintenance of their populations.

Proportion of bird and tree species classified as ‘Winners’ which would benefit under land sparing (Pink), or land sharing (Light blue), and ‘Losers’ which would benefit from land sparing (Red) and land sharing (dark blue). Grey represents species with more complex yield-abundance relationships. Taken from Phalan et al

On the whole they found that land sparing was the best option for most species, particularly for those species with small global ranges.This is important since it is largely these species that are considered to be conservation priorities.

However, some people have interpreted this as meaning that the authors advocate land sparing in all situations. Even if they do, it is obvious that land sparing might not be the best strategy in all situations. Different landscapes have different histories of land use, which will have inevitably had an effect on biodiversity and consequently what we see as priorities for protection.

For example, much of Western Europe has been cultivated for centuries if not millennia and has little forest cover. As a result the biodiversity we value here consists largely of  generalist species which thrive in low intensity farmland and require some form of agricultural practice for persistence. Meadows are a great example of a cultural landscape that is highly valued in Europe but requires disturbance, such as grazing, to exist. In situations like these it is entirely possible that land sharing may help to boost the populations of priority species.

Land sparing – great for pristine forest, rubbish for cultural landscapes? (Photo credit goes to Jenny Downing on flickr)

In addition the taxonomic group which you aim to protect will determine the scale at which management should be undertaken. What constitutes land sparing for an invertebrate will not be the same as that for a bird. Phalan et al’s paper arguably chose taxonomic groups which would be likely to benefit from large scale land sparing, it will be interesting to see how research into other taxa differs in their findings.

Ecosystem services will also be affected by these different land use strategies. Land sharing may favour services which rely on fragments of semi-natural habitat in order to be distributed throughout the landscape, such as pollination. Meanwhile services which are supplied far away from ecosystems which generate them, such as carbon storage and water purification, will be favoured by land sparing.

Though food production is an obvious priority, lots of conservation essentially adds up to how best to use particular parcels of land to meet multiple goals. Land sparing vs land sharing could be applied to urban planning and energy production to name just two. Hopefully, if my PhD doesn’t get in the way, I will explore this issues further in the coming weeks.

The land sparing vs land sharing debate is obviously set to run and run. However, it seems likely that with more research we may be able to form some generalisations. In areas where there are many species which depend on forests, or any other ecosystem incompatible with agriculture, land sparing may be best while land sharing may work best in areas with a long history of extensive farming and little forest cover.

Much work is needed to determine the consequences of these options for ecosystem services and also the social implications. For example, could promoting land sparing further add to our lack of connection with nature? What exactly is the relationship between provision of particular ecosystem services and these different options? I don’t have the answer to these questions. However, given that agriculture is the biggest single threat to biodiversity, but is something none of us can live without, I hope we will at least have a few more answers in the near future.