A guide to conservation land management and greenhouse gas emissionsstill release GHGs – albeit atlower levels – but without thebenefit of providing food forhuman consumption.If considering replacinggrazing with cutting, it issimilarly important to bear inmind that these different formsof management also have quitedifferent effects on the vegetationand its inhabitants. In particular,mowing, by removing all ofthe vegetation in an area in onego, is catastrophic for manyinvertebrates; tends to produce amore uniform vegetation structurethan medium levels of livestockgrazing; is typically unselective inthe plant species that it removes;Ponies release lower levels of methane per quantity of vegetationand does not create gaps in theremoved compared to cattle or sheep. Natural England/Petersward that are necessary forRoworth (CC BY-NC-ND 2.0)plants to regenerate. Patchy androtational cutting can, though, be used to createbut, as shown in Table 1, sheep actually causemore warming per livestock unit (i.e. per quantity structural mosaics and might be a realistic alternativeto livestock grazing at small sites, especially thoseof vegetation removed).where grazing is in any case difficult.A common suggestion is to replace cattle withThe GHG flux from managing vegetationponies. If you are considering this, it is important toby cutting will vary according to the fate of therecognise that cattle and ponies have quite differentcut material. Using arisings from conservationeffects on vegetation structure and composition,management to provide biomass (i.e. to burn toand consequently on the vegetation’s inhabitants. Inrelease energy) or for composting can be valuableaddition, there is evidence that ponies trample moreways of disposing of otherwise unwanted material,birds’ nests per quantity of vegetation removed thanas well as sometimes generating an income tocattle (Mandema et al. 2013). There do not appearhelp fund conservation work. The use of biomassto be significant differences in levels of methanemight, to a very limited extent, displace the burningemissions between different breeds of livestock, withof fossil fuels. Meanwhile, composting will notany differences in overall GHG emissions beingsignificantly affect the GHG flux from a habitat,due to their feed intake and the type of productioncompared to leaving the arisings to decompose insystem (Dewhurst & Miller 2019). While replacingsitu. By contrast, using timber for construction willcommercial cattle with ponies will reduce GHGbenefit the climate by locking up the carbon in it.emissions at a given site, the latter will neverthelessTable 1. The estimated greenhouse gas (GHG) emissions, expressed as GWP100, from different types oflivestock. Data for GHG emissions are from IPCC (2019). Data on livestock units per animal are from RuralPayments Agency (2021).Type of livestockLivestock units per animalGHG emissions (t CO2e per year)Per animalPer livestock unitMature beef cow1.01.4041.4A sheep and its lamb0.1*0.2432.4Pony0.80.4860.6* Mean of value for upland and lowland sheepConservation Land Management Summer 2022 | Vol. 20 No. 2 27
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