Editing IPCC:AR6/WGII/Chapter-2 (section)

===== 2.4.4.4.3 Biodiversity and observed terrestrial ecosystem carbon =====

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High biodiversity and ecosystem carbon generally occur together, with rainforests in the Amazon, Congo and Indonesia containing the largest above-ground vegetation carbon stocks ( [[#Saatchi--2011|Saatchi et al., 2011]] ; [[#Baccini--2012|Baccini et al., 2012]] ; [[#Avitabile--2016|Avitabile et al., 2016]] ) and the highest vascular plant species richness ( [[#Kreft--2007|Kreft and Jetz, 2007]] ) in the world. Above-ground ecosystem carbon and animal species richness show high correlation but also high spatial variability ( [[#Strassburg--2010|Strassburg et al., 2010]] ). Above-ground carbon is correlated to genus richness globally ( [[#Cavanaugh--2014|Cavanaugh et al., 2014]] ), but to species richness only in local areas ( [[#Poorter--2015|Poorter et al., 2015]] ; [[#Sullivan--2017|Sullivan et al., 2017]] ). Species richness generally increases vegetation productivity in the humid tropics while tree abundance increases productivity in drier conditions ( [[#Madrigal-Gonzalez--2020|Madrigal-Gonzalez et al., 2020]] ). Across the Amazon, ~1% of tree species contain 50% of the above-ground carbon, due to abundance and maximum height ( [[#Fauset--2015|Fauset et al., 2015]] ). Above-ground carbon in tropical forests shows positive correlations to vertebrate species richness (P values not reported) ( [[#Deere--2018|Deere et al., 2018]] ; [[#Di%20Marco--2018|Di Marco et al., 2018]] ). In logged and burned tropical forest in Brazil, species richness of plants, birds and beetles increased with carbon density up to ~100 tonnes ha -1 ( [[#Ferreira--2018|Ferreira et al., 2018]] ).

National parks and other protected areas which, in June 2021, covered 15.7% of global terrestrial area (UNEP-WCMC et al., 2021) contain ~90 GtC in vegetation and ~150 GtC in soil (one-fifth and one-tenth, respectively, of global stocks) and remove carbon from the atmosphere at a rate of ~0.5 Gt yr -1 (one-sixth of global removals) ( [[#Melillo--2016|Melillo et al., 2016]] ). The most strictly protected areas contain carbon at higher densities, but illegal deforestation and fires in some protected areas emit 38 ± 17 Mt yr -1 globally ( [[#Collins--2017|Collins and Mitchard, 2017]] ). In the Amazon, protected areas store more than half of the above-ground vegetation carbon stocks of the region, but account for only one-tenth of net emissions ( [[#Walker--2020|Walker et al., 2020]] ). Conservation of high biodiversity areas, particularly in protected areas, protects ecosystem carbon, prevents emissions to the atmosphere and reduces the magnitude of climate change ( ''high confidence'' ).

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