Livestock excels at valorizing marginal land that is unsuitable for crop agriculture. Although concerns related to land use for feed and land use change are legitimate, radical afforestation and rewilding scenarios are simplistic. Depictions of animal husbandry as devastating for biodiversity use worst-case examples, that can also be found for plant agriculture. When agroecological principles are respected, well-managed grasslands boost biodiversity and soil health, while being a carbon sink, delivering nutrition, and contributing to livelihoods.
Expansion in agricultural land is a probable pathway to meet the food demands of a global growing population, although the extend will depend on yields and socio-economic responses [Pal et al. 2020]. This, however, would give rise to deforestation and thereby threaten biodiversity and worsen climate scenarios. Similarly, aquaculture expansion has been accused of having negative effects on ecosystems [Barange et al. 2018]. Both deforestation and harmful pressure on oceans and waterways are fundamental threats of which the halting needs to prioritised. According to FAO's COP28 roadmap, zero net- and zero gross-deforestation need to be achieved globally by 2030 and 2050, respectively, whereas all illegal, unreported, and unregulated fisheries activities will have to be phased out by 2030 [FAO 2023].
Land use by livestock is said to threaten biodiversity and to come with opportunity costs. Alternative land use strategies consist of (1) rewilding for biodiversity, (2) a switch to cropland to produce more food [see elsewhere], or (3) afforestation to sequester carbon [see elsewhere]. Vegan and vegetarian food systems, in contrast, would require less land surface [Meier & Christen 2013; Kurtz et al. 2020]. Although land use alternatives offer a reasonable case in some areas, these assumption come with several constraints and the practical reality is far more intricate.
Land is not to be seen as a highly convertible resource
Land should not be regarded as a homogeneous and perfectly flexible resource [FAO]. Worldwide, non-convertible
pastures and rangelands constitute a quarter (1.26 billion ha) of the agricultural surface. Only one third (0.68 billion ha) of the grassland that is now used for animal husbandry could be converted into crop land [Mottet et al. 2017]. High-productivity lands are already under crop production and, moreover, are usually characterized by low biodiversity levels [Huston 2005].
The availability of arable land is also very region-dependent [FAO]. World Bank data indicates that the share of arable land varies largely between countries like Germany, Denmark, France, and Spain (50-60%) and most of the Nordic countries (<10%). In Norway, for instance, only 3% is arable land while 45% is good pastureland. The country's grain production is moreover more suited for feed than for food due to climate conditions [Thorkildsen & Reksnes 2020]. In Wales, 81% of farmland is permanent grassland, and not suitable for producing other types of food [Hybu Cig Cymru 2020].
Livestock valorizes marginal lands
One of livestock's main strengths is precisely that it is able to make valuable use of marginal lands [FAO], i.e., with low opportunity costs for arable production [Van Zanten et al. 2016]. While elimination of livestock would reduce total land use by food with 76% (some 3 billion ha), the decrease in arable land would only be 19% [Poore & Nemecek 2018]. Taking out beef & mutton would decrease arable land with just 6% [Poore & Nemecek 2018, suppl.]. Moreover, this would come with various trade-offs. Livestock can turn out to be nutritionally and economically more efficient, while providing food and livelihoods, and allowing for high levels of biodiversity (provided that certain agro-ecological- principles are respected) [Manzano-Baena & Salguero-Herrera 2018].
If not used for animal agriculture, non-convertible grasslands (2/3 of the total) would have to be withdrawn from the food system, undermining food security. Areas most suitable for rewilding and afforestation are also generally situated in countries where livestock is essential to local food security and livelihoods [Strassburg et al. 2020; Kim et al. 2020]. In some regions, this issue will become even more pertinent in the future as lands will become increasingly marginal due to climate change, so that land valorization with livestock will be vital for food security [Jones & Thornton 2009].
Explanatory video 💬 Dairy Cares 2019; del Prado & Manzano 2023
Food quality and waste should be factored in
Ultra-processed foods should be a main target for waste reduction given that they are not nutritionally essential (and likely harmful for human health), while accounting for one third of food waste of adults in high-income countries [Anastasiou et al. 2022]. They also lead to one third of land use, although the latter is mostly ascribed to "processed meats" and much less to meat-free ultra-processed variants. However, mildly processed and ultra-processed meats are often lumped into one category of "processed meats" without robust justification. To further complicate the picture, it is not only the quantity of land used but also the impacts of that use on ecosystems, of which the effects are concentrated in a few key crops and crop-growing regions. Continued growth of the ultra-processed food market leads to increased palm and soy oil production in high-biodiversity areas that are already hit by deforestation [Lee et al. 2016]. In the Swedish diet, the category "sweets, snacks, and drinks" (in particular cocoa, vegetable oils, coffee, and nuts) lead to the largest biodiversity loss (45% of total impact) [Moberg et al. 2020].
Land sparing is not necessarily better than sharing
Given some of the harmful outcomes of animal husbandry, such as deforestation [Herrero et al. 2009], some authors have suggested that carnivory drives vertebrate extinction [Coimbra et al. 2022], so that plant-based diets are needed to restore ecosystems and prevent biodiversity losses [Leclère et al. 2020]. Biodiversity concerns are certainly valid, but require a focus on specific targets. The often claimed 'mean vertebrate decline' of >50% since 1970 [WWF 2018], for instance, is excessively catastrophic and driven by an extreme decline in a small minority of populations (1%) only [Leung et al. 2020]. In Europe, mammal diversity can even be considered as similar to 8000 years ago and a further reintroduction of "regionally extirpated species and domestic descendants of 'extinct' species to provide replacement grazing, browsing, and predation" may lead to net gains [Hatfield et al. 2022]. Conservation strategies need to be addressed accordingly.
The biodiversity challenge is situated in a debate that contrasts land sparing (high-yield farming opening up land for rewilding) with sharing (wildlife-friendly farming) [Green et al. 2005]. Land sparing, through the segregation of agriculture and nature, is said to improve biodiversity levels in 'protected areas' [Phalan et al. 2011; Kamp et al. 2015; Dotta et al. 2016; Williams et al. 2017; Phalan 2018]. Others, defending the sharing approach, find this misleading and argue that such conclusions are not valid on the long term. In contrast, biodiversity conservation should be integrated into the landscapes used by humans to avoid mass extinction and ecosystem collapse
[Kremen & Merenlender 2018].
Outcomes depend on praxis
Once more, it is not so simple as ASFs versus plants. Whether
land use is net beneficial or harmful for
biodiversity, or a result of deforestation, is largely a matter of praxis and how managers respond to environmental variability [Peyraud & MacLeod 2020; Kleppel 2020]. Both plant and animal agriculture can be either regenerative, benign, or devastating [for the example of deforestation due to the cultivation of avocados, cf. del Castillo 2023].
It is true that deforestation for soy is linked to feed production and should be halted, but one needs to bear in mind that a substantial part of the generated value is also related to soybean oil production and bioethanol. Moreover, the practice is in essence a form of land speculation and economic expansion. Even in the absence of farming, other activities would continue driving the process (logging, mining, etc.) The problem is thus not livestock agriculture as such but an extractive industrial model that needs to be tackled at its root.
Grasslands provide more biodiversity than row crop agriculture
The conversion of natural ecosystems to agricultural land may be the world's largest threat to species extinction [Tilman et al. 2017]. This is, however, very much a generalization that overlooks huge differences between agricultural systems. Overall, the production of crops has twice as much negative impact on
the biodiversity of mammals, birds, and amphibians than livestock, while
rangelands tend to promote habitat diversity [FAO 2013]. In Europe, about half of the endemic plant species are dependent on the
grassland biotope, while half of the bird species depend on grassland
habitats for food and reproduction [Peyraud & MacLeod 2020]. As a result, the conversion of permanent grassland to arable land is the
main driver of biodiversity losses at the landscape level [Peyraud & MacLeod 2020]. Again, however, systems need to be compared on a case-by-case basis as both crop and animal agriculture can be either net positive or negative for biodiversity.
Cereals - used for both food and feed - often constitute a threat to
biodiversity worldwide. This is due to the fact that they require
conversion and simplification of large extents of land, paralleling
degradation of
habitats,
deforestation, and direct threats to species [FAO 2013].
Starchy roots, oil crops, and pulses also have considerable
biodiversity impacts, as they are increasingly grown in monocultures and
cause deforestation [FAO 2013]. It is important to point out that 36-45% of diet-related biodiversity loss in a range of high-income countries is associated with the consumption of ultra-processed foods, which are in many (if not most) cases based on inputs from such monocultures [Anastasiou et al. 2022]. Conversion of row crop agriculture land to properly grazed
pastures thus has the potential to result in healthier top soils, and
all the biodiversity and environmental benefits this may generate [Machmuller et al. 2015].
Usually, integration of livestock and crop systems positively affect soil health and, thus, crop production [Kumar et al. 2019]. In some regions, however, badly managed grazing can parallel land clearing for
pastures, lead to habitat fragmentation and degradation, and result in
biodiversity decline [FAO 2013; Kleppel 2020].
Explanatory video 💬 del Prado & Manzano 2023
Grazing management holds particular potential for biodiversity improvements
Semi-natural grasslands can harbor a lot of biodiversity, albeit dependent on a variety of factors (e.g., grazing management) [Dumont et al. 2009; Kleppel 2020]. Maintaining well-connected core
semi-natural habitat by properly moving livestock yields functional connectivity and acts as a dispersal vector for plants [Kimberley et al. 2020]. With supportive incentives to protect mobility and avoid fragmentation of rangelands, livestock production can be compatible with vegetative and wildlife diversity [Russell et al. 2018; Paul et al. 2021]. Both animal and plant biodiversity can thus be largely improved by proper grazing strategies.
This holds especially true when livestock is managed to create shifting focal patches and evolutionary grazing patterns. This can be done by using multi-paddock approaches that mimic behaviour of wildlife, such as bison in the Great Plains of North America [Milchunas et al. 1988; Fuhlendorf & Engle 2001; Cassidy & Kleppel 2017; Girard-Cartier & Kleppel 2017; Teague & Barnes 2017; Hillenbrand et al. 2019].
At the same time, the technique promotes richness of the soil microbiome and thereby soil health [Teague et al. 2011; Kleppel 2019]. Results have not yet been sufficiently formalized in peer-reviewed literature, but some ranchers have reported impressive results (e.g., an increases of soil organic matter from 2 to 11% over two decades by Gabe Brown) [Kleppel 2020]. Success remains nonetheless contextual [Kleppel 2020].
For a science compendium on well-managed grazing, see: Soil4Climate 2023
Explanatory video 💬 Williams 2024
Forests are not necessarily more 'Natural' than grasslands
Rewilding proponents frequently hold romanticized ideas about a return to a Nature, which needs to start with massive afforestation. Yet, it is important to consider that almost half of the total global
land area in the Pleistocene consisted of grasslands [Zimov 2005]. Such grazing ecosystems co-evolved with ruminants over the last 40 million years, yielding carbon-rich soils in semi-arid to
semi-humid regions [Frank et al. 1998; Retallack 2014]. As stated by Strömberg et al. [2020], "the history of humans has been profoundly intertwined with grassy biomes". They add that livestock production now "centers in areas that were once (and sometimes still are) native grasslands".
Afforesting the marginal lands now used by livestock would largely ignore the open and non-forested character of many of these landscapes as a pre-human baseline [Pausas & Bond 2019; Scoones 2021], including Europe's temperate forest biome that was naturally maintained by large herbivores [Pearce et al. 2023]. Such landscapes are nonetheless often targeted for ‘restoration’ by 2030 by such organizations as the World Wildlife Fund (WWF) and the World Resources Institute (WRI) [Minnemeyer et al. 2014]. In Africa, for instance, this includes 1 million km2 of open grasslands, including rangelands [Bond et al. 2019]. In fact, 40% of the WRI map (some 1 billion hectares), includes grassy biomes [Veldman et al. 2015]. Their undifferentiated afforestation would be based on the erroneous assumption that such biomes are in a deforested and degraded state [Bond et al. 2019]. It would lead to landscapes not all that different from current grazed ones [Manzano & White 2019], and overlooks the complementary actions of fire and grazing in landscape-sculpting [Bond, 2019]. Moreover, afforesting grasslands with flammable plantation trees in vulnerable regions would introduce risk for high-intensity fires compared to lower intensity grass-fuelled fires [Stevens & Bond 2023], while devastating biodiversity and ecosystem services [Veldman et al. 2015].
According to PASTRES [2022], initiatives that have a narrow focus on tree planting as a way to "combat desertification, improve biodiversity, and address climate change through ‘carbon offset’ schemes" are "often deeply problematic, yet have targeted over one billion hectares of rangelands across the world", thereby overlooking fundamental ecological constraints. They add: "covering over half the world’s land surface, rangelands - as ‘open ecosystems’ – require a very different approach", in which pastoralism should play an important role [PASTRES 2022].
Explanatory video 💬 Bond 2020
Grazed lands sometimes provide better options than forests
Although forests are important carbon sinks, this is certainly also true for grasslands [see elsewhere]. In some cases, especially under the threat of forest fires, they may even be considered as more reliable [Dass et al. 2018]. Satellite analysis has revealed that forest offsets may not even be doing much for the climate [Coffield & Randerson 2022; Coffield et al. 2022]. Lucrative afforestation, based on carbon credit incentives, may even come at a biodiversity cost and with environmental or hydrological stress [Jackson et al. 2005; Carnus et al. 2006; Cao 2008; Parr et al. 2012; Honda & Durigan 2016; Abreu et al. 2017], while having a destructive effect on rural communities [e.g., for the replacement of sheep farming by monocultures in New Zealand, see McClure 2023].
Savannas would simply disappear without large herbivores. Cattle grazing helps to further reduce fire hazards by reducing fine fuels and by slowing the encroachment of shrubs and
trees onto grasslands [Lasanta et al. 2018; Ratcliff et al. 2020]. Without sufficient grazing, grass productivity decreases because grass litter shades and insulates the soil. As a result of lower soil fertility, shrubs and mosses take over from grass as they have lower nutrient
requirements [Zimov 2005].
Grasslands, livestock, and trees can be integrated
Rather than from massive top-down afforestation schemes that exclude
local farmers and communities, there is much more to be expected from
conservation actions through cooperation. This would enhance
agricultural practices, halt ongoing deforestation, and lead to more
localized and realistic actions. Also, it may not be so much a question of grass versus trees than a matter of integrating grasslands and trees in their most optimal configurations. Silvopastoralism provides interesting options.
